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Neonatal Pathophysiology


Neonatal Pathophysiology

Writer and Curator: Larry H. Bernstein, MD, FCAP 

 

Introduction

This curation deals with a large and specialized branch of medicine that grew since the mid 20th century in concert with the developments in genetics and as a result of a growing population, with large urban populations, increasing problems of premature deliveries.  The problems of prematurity grew very preterm to very low birth weight babies with special problems.  While there were nurseries, the need for intensive care nurseries became evident in the 1960s, and the need for perinatal care of pregnant mothers also grew as a result of metabolic problems of the mother, intrauterine positioning of the fetus, and increasing numbers of teen age pregnancies as well as nutritional problems of the mother.  There was also a period when the manufacturers of nutritional products displaced the customary use of breast feeding, which was consequential.  This discussion is quite comprehensive, as it involves a consideration of the heart, the lungs, the brain, and the liver, to a large extent, and also the kidneys and skeletal development.

It is possible to outline, with a proportionate emphasis based on frequency and severity, this as follows:

  1. Genetic and metabolic diseases
  2. Nervous system
  3. Cardiovascular
  4. Pulmonary
  5. Skeletal – bone and muscle
  6. Hematological
  7. Liver
  8. Esophagus, stomach, and intestines
  9. Kidneys
  10. Immune system

Fetal Development

Gestation is the period of time between conception and birth when a baby grows and develops inside the mother’s womb. Because it’s impossible to know exactly when conception occurs, gestational age is measured from the first day of the mother’s last menstrual cycle to the current date. It is measured in weeks. A normal gestation lasts anywhere from 37 to 41 weeks.

Week 5 is the start of the “embryonic period.” This is when all the baby’s major systems and structures develop. The embryo’s cells multiply and start to take on specific functions. This is called differentiation. Blood cells, kidney cells, and nerve cells all develop. The embryo grows rapidly, and the baby’s external features begin to form.

Week 6-9:   Brain forms into five different areas. Some cranial nerves are visible. Eyes and ears begin to form. Tissue grows that will the baby’s spine and other bones. Baby’s heart continues to grow and now beats at a regular rhythm. Blood pumps through the main vessels. Your baby’s brain continues to grow. The lungs start to form. Limbs look like paddles. Essential organs begin to grow.

Weeks 11-18: Limbs extended. Baby makes sucking motion. Movement of limbs. Liver and pancreas produce secretions. Muscle and bones developing.

Week 19-21: Baby can hear. Mom feels baby – and quickening.

http://www.nlm.nih.gov/medlineplus/ency/article/002398.htm

fetal-development

fetal-development

https://polination.files.wordpress.com/2014/02/abortion-new-research-into-fetal-development.jpg

Inherited Metabolic Disorders

The original cause of most genetic metabolic disorders is a gene mutation that occurred many, many generations ago. The gene mutation is passed along through the generations, ensuring its preservation.

Each inherited metabolic disorder is quite rare in the general population. Considered all together, inherited metabolic disorders may affect about 1 in 1,000 to 2,500 newborns. In certain ethnic populations, such as Ashkenazi Jews (Jews of central and eastern European ancestry), the rate of inherited metabolic disorders is higher.

Hundreds of inherited metabolic disorders have been identified, and new ones continue to be discovered. Some of the more common and important genetic metabolic disorders include:

Lysosomal storage disorders : Lysosomes are spaces inside cells that break down waste products of metabolism. Various enzyme deficiencies inside lysosomes can result in buildup of toxic substances, causing metabolic disorders including:

  • Hurler syndrome (abnormal bone structure and developmental delay)
  • Niemann-Pick disease (babies develop liver enlargement, difficulty feeding, and nerve damage)
  • Tay-Sachs disease (progressive weakness in a months-old child, progressing to severe nerve damage; the child usually lives only until age 4 or 5)
  • Gauchers disease and others

Galactosemia: Impaired breakdown of the sugar galactose leads to jaundice, vomiting, and liver enlargement after breast or formula feeding by a newborn.

Maple syrup urine disease: Deficiency of an enzyme called BCKD causes buildup of amino acids in the body. Nerve damage results, and the urine smells like syrup.

Phenylketonuria (PKU): Deficiency of the enzyme PAH results in high levels of phenylalanine in the blood. Mental retardation results if the condition is not recognized.

Glycogen storage diseases: Problems with sugar storage lead to low blood sugar levels, muscle pain, and weakness.

Metal metabolism disorders: Levels of trace metals in the blood are controlled by special proteins. Inherited metabolic disorders can result in protein malfunction and toxic accumulation of metal in the body:

Wilson disease (toxic copper levels accumulate in the liver, brain, and other organs)

Hemochromatosis (the intestines absorb excessive iron, which builds up in the liver, pancreas, joints, and heart, causing damage)

Organic acidemias: methylmalonic acidemia and propionic acidemia.

Urea cycle disorders: ornithine transcarbamylase deficiency and citrullinemia

Hemoglobinopathies – thalassemias, sickle cell disease

Red cell enzyme disorders – glucose-6-phosphate dehydrogenase, pyruvate kinase

This list is by no means complete.

http://www.webmd.com/a-to-z-guides/inherited-metabolic-disorder-types-and-treatments

New variations in the galactose-1-phosphate uridyltransferase (GALT) gene

Clinical and molecular spectra in galactosemic patients from neonatal screening in northeastern Italy: Structural and functional characterization of new variations in the galactose-1-phosphate uridyltransferase (GALT) gene

E Viggiano, A Marabotti, AP Burlina, C Cazzorla, MR D’Apice, et al.
Gene 559 (2015) 112–118
http://dx.doi.org/10.1016/j.gene.2015.01.013
Galactosemia (OMIM 230400) is a rare autosomal recessive inherited disorder caused by deficiency of galactose-1-phosphate uridyltransferase (GALT; OMIM 606999) activity. The incidence of galactosemia is 1 in 30,000–60,000, with a prevalence of 1 in 47,000 in the white population. Neonates with galactosemia can present acute symptoms, such as severe hepatic and renal failure, cataract and sepsis after milk introduction. Dietary restriction of galactose determines the clinical improvement in these patients. However, despite early diagnosis by neonatal screening and dietary treatment, a high percentage of patients develop long-term complications such as cognitive disability, speech problems, neurological and/or movement disorders and, in females, ovarian dysfunction.

With the benefit of early diagnosis by neonatal screening and early therapy, the acute presentation of classical galactosemia can be prevented. The objectives of the current study were to report our experience with a group of galactosemic patients identified through the neonatal screening programs in northeastern Italy during the last 30 years.

No neonatal deaths due to galactosemia complications occurred after the introduction of the neonatal screening program. However, despite the early diagnosis and dietary treatment, the patients with classical galactosemia showed one or more long-term complications.

A total of 18 different variations in the GALT gene were found in the patient cohort: 12 missense, 2 frameshift, 1 nonsense, 1 deletion, 1 silent variation, and 1 intronic. Six (p.R33P, p.G83V, p.P244S, p.L267R, p.L267V, p.E271D) were new variations. The most common variation was p.Q188R (12 alleles, 31.5%), followed by p.K285N (6 alleles, 15.7%) and p.N314D (6 alleles, 15.7%). The other variations comprised 1 or 2 alleles. In the patients carrying a new mutation, the biochemical analysis of GALT activity in erythrocytes showed an activity of < 1%. In silico analysis (SIFT, PolyPhen-2 and the computational analysis on the static protein structure) showed potentially damaging effects of the six new variations on the GALT protein, thus expanding the genetic spectrum of GALT variations in Italy. The study emphasizes the difficulty in establishing a genotype–phenotype correlation in classical galactosemia and underlines the importance of molecular diagnostic testing prior to making any treatment.

Diagnosis and Management of Hereditary Hemochromatosis

Reena J. Salgia, Kimberly Brown
Clin Liver Dis 19 (2015) 187–198
http://dx.doi.org/10.1016/j.cld.2014.09.011

Hereditary hemochromatosis (HH) is a diagnosis most commonly made in patients with elevated iron indices (transferrin saturation and ferritin), and HFE genetic mutation testing showing C282Y homozygosity.

The HFE mutation is believed to result in clinical iron overload through altering hepcidin levels resulting in increased iron absorption.

The most common clinical complications of HH include cirrhosis, diabetes, nonischemic cardiomyopathy, and hepatocellular carcinoma.

Liver biopsy should be performed in patients with HH if the liver enzymes are elevated or serum ferritin is greater than 1000 mg/L. This is useful to determine the degree of iron overload and stage the fibrosis.

Treatment of HH with clinical iron overload involves a combination of phlebotomy and/or chelation therapy. Liver transplantation should be considered for patients with HH-related decompensated cirrhosis.

Health economic evaluation of plasma oxysterol screening in the diagnosis of Niemann–Pick Type C disease among intellectually disabled using discrete event simulation

CDM van Karnebeek, Tima Mohammadi, Nicole Tsaod, Graham Sinclair, et al.
Molecular Genetics and Metabolism 114 (2015) 226–232
http://dx.doi.org/10.1016/j.ymgme.2014.07.004

Background: Recently a less invasive method of screening and diagnosing Niemann–Pick C (NP-C) disease has emerged. This approach involves the use of a metabolic screening test (oxysterol assay) instead of the current practice of clinical assessment of patients suspected of NP-C (review of medical history, family history and clinical examination for the signs and symptoms). Our objective is to compare costs and outcomes of plasma oxysterol screening versus current practice in diagnosis of NP-C disease among intellectually disabled (ID) patients using decision-analytic methods.
Methods: A discrete event simulation model was conducted to follow ID patients through the diagnosis and treatment of NP-C, forecast the costs and effectiveness for a cohort of ID patients and compare the outcomes and costs in two different arms of the model: plasma oxysterol screening and routine diagnosis procedure (anno 2013) over 5 years of follow up. Data from published sources and clinical trials were used in simulation model. Unit costs and quality-adjusted life-years (QALYs) were discounted at a 3% annual rate in the base case analysis. Deterministic and probabilistic sensitivity analyses were conducted.
Results: The outcomes of the base case model showed that using plasma oxysterol screening for diagnosis of NP-C disease among ID patients is a dominant strategy. It would result in lower total cost and would slightly improve patients’ quality of life. The average amount of cost saving was $3642 CAD and the incremental QALYs per each individual ID patient in oxysterol screening arm versus current practice of diagnosis NP-C was 0.0022 QALYs. Results of sensitivity analysis demonstrated robustness of the outcomes over the wide range of changes in model inputs.
Conclusion: Whilst acknowledging the limitations of this study, we conclude that screening ID children and adolescents with oxysterol tests compared to current practice for the diagnosis of NP-C is a dominant strategy with clinical and economic benefits. The less costly, more sensitive and specific oxysterol test has potential to save costs to the healthcare system while improving patients’ quality of life and may be considered as a routine tool in the NP-C diagnosis armamentarium for ID. Further research is needed to elucidate its effectiveness in patients presenting characteristics other than ID in childhood and adolescence.

Neurological and Behavioral Disorders

Estrogen receptor signaling during vertebrate development

Maria Bondesson, Ruixin Hao, Chin-Yo Lin, Cecilia Williams, Jan-Åke Gustafsson
Biochimica et Biophysica Acta 1849 (2015) 142–151
http://dx.doi.org/10.1016/j.bbagrm.2014.06.005

Estrogen receptors are expressed and their cognate ligands produced in all vertebrates, indicative of important and conserved functions. Through evolution estrogen has been involved in controlling reproduction, affectingboth the development of reproductive organs and reproductive behavior. This review broadly describes the synthesis of estrogens and the expression patterns of aromatase and the estrogen receptors, in relation to estrogen functions in the developing fetus and child. We focus on the role of estrogens for the development of reproductive tissues, as well as non-reproductive effects on the developing brain. We collate data from human, rodent, bird and fish studies and highlight common and species-specific effects of estrogen signaling on fetal development. Morphological malformations originating from perturbed estrogen signaling in estrogen receptor and aromatase knockout mice are discussed, as well as the clinical manifestations of rare estrogen receptor alpha and aromatase gene mutations in humans. This article is part of a Special Issue entitled: Nuclear receptors in animal development.

 

Memory function and hippocampal volumes in preterm born very-low-birth-weight (VLBW) young adults

Synne Aanes, Knut Jørgen Bjuland, Jon Skranes, Gro C.C. Løhaugen
NeuroImage 105 (2015) 76–83
http://dx.doi.org/10.1016/j.neuroimage.2014.10.023

The hippocampi are regarded as core structures for learning and memory functions, which is important for daily functioning and educational achievements. Previous studies have linked reduction in hippocampal volume to working memory problems in very low birth weight (VLBW; ≤1500 g) children and reduced general cognitive ability in VLBW adolescents. However, the relationship between memory function and hippocampal volume has not been described in VLBW subjects reaching adulthood. The aim of the study was to investigate memory function and hippocampal volume in VLBW young adults, both in relation to perinatal risk factors and compared to term born controls, and to look for structure–function relationships. Using Wechsler Memory Scale-III and MRI, we included 42 non-disabled VLBW and 61 control individuals at age 19–20 years, and related our findings to perinatal risk factors in the VLBW-group. The VLBW young adults achieved lower scores on several subtests of the Wechsler Memory Scale-III, resulting in lower results in the immediate memory indices (visual and auditory), the working memory index, and in the visual delayed and general memory delayed indices, but not in the auditory delayed and auditory recognition delayed indices. The VLBW group had smaller absolute and relative hippocampal volumes than the controls. In the VLBW group inferior memory function, especially for the working memory index, was related to smaller hippocampal volume, and both correlated with lower birth weight and more days in the neonatal intensive care unit (NICU). Our results may indicate a structural–functional relationship in the VLBW group due to aberrant hippocampal development and functioning after preterm birth.

The relation of infant attachment to attachment and cognitive and behavioural outcomes in early childhood

Yan-hua Ding, Xiu Xua, Zheng-yan Wang, Hui-rong Li, Wei-ping Wang
Early Human Development 90 (2014) 459–464
http://dx.doi.org/10.1016/j.earlhumdev.2014.06.004

Background: In China, research on the relation of mother–infant attachment to children’s development is scarce.
Aims: This study sought to investigate the relation of mother–infant attachment to attachment, cognitive and behavioral development in young children.                                                                                                                            Study design: This study used a longitudinal study design.
Subjects: The subjects included healthy infants (n=160) aged 12 to 18 months.
Outcome measures: Ainsworth’s “Strange Situation Procedure” was used to evaluate mother–infant attachment types. The attachment Q-set (AQS) was used to evaluate the attachment between young children and their mothers. The Bayley scale of infant development-second edition (BSID-II) was used to evaluate cognitive developmental level in early childhood. Achenbach’s child behavior checklist (CBCL) for 2- to 3-year-oldswas used to investigate behavioral problems.
Results: In total, 118 young children (73.8%) completed the follow-up; 89.7% of infants with secure attachment and 85.0% of infants with insecure attachment still demonstrated this type of attachment in early childhood (κ = 0.738, p b 0.05). Infants with insecure attachment collectively exhibited a significantly lower mental development index (MDI) in early childhood than did infants with secure attachment, especially the resistant type. In addition, resistant infants were reported to have greater social withdrawal, sleep problems and aggressive behavior in early childhood.
Conclusion: There is a high consistency in attachment development from infancy to early childhood. Secure mother–infant attachment predicts a better cognitive and behavioral outcome; whereas insecure attachment, especially the resistant attachment, may lead to a lower cognitive level and greater behavioral problems in early childhood.

representations of the HPA axis

representations of the HPA axis

representations of limbic stress-integrative pathways from the prefrontal cortex, amygdala and hippocampus

representations of limbic stress-integrative pathways from the prefrontal cortex, amygdala and hippocampus

Fetal programming of schizophrenia: Select mechanisms

Monojit Debnatha, Ganesan Venkatasubramanian, Michael Berk
Neuroscience and Biobehavioral Reviews 49 (2015) 90–104
http://dx.doi.org/10.1016/j.neubiorev.2014.12.003

Mounting evidence indicates that schizophrenia is associated with adverse intrauterine experiences. An adverse or suboptimal fetal environment can cause irreversible changes in brain that can subsequently exert long-lasting effects through resetting a diverse array of biological systems including endocrine, immune and nervous. It is evident from animal and imaging studies that subtle variations in the intrauterine environment can cause recognizable differences in brain structure and cognitive functions in the offspring. A wide variety of environmental factors may play a role in precipitating the emergent developmental dysregulation and the consequent evolution of psychiatric traits in early adulthood by inducing inflammatory, oxidative and nitrosative stress (IO&NS) pathways, mitochondrial dysfunction, apoptosis, and epigenetic dysregulation. However, the precise mechanisms behind such relationships and the specificity of the risk factors for schizophrenia remain exploratory. Considering the paucity of knowledge on fetal programming of schizophrenia, it is timely to consolidate the recent advances in the field and put forward an integrated overview of the mechanisms associated with fetal origin of schizophrenia.

NMDA receptor dysfunction in autism spectrum disorders

Eun-Jae Lee, Su Yeon Choi and Eunjoon Kim
Current Opinion in Pharmacology 2015, 20:8–13
http://dx.doi.org/10.1016/j.coph.2014.10.007

Autism spectrum disorders (ASDs) represent neurodevelopmental disorders characterized by two core symptoms;

(1)  impaired social interaction and communication, and
(2)  restricted and repetitive behaviors, interests, and activities.

ASDs affect ~ 1% of the population, and are considered to be highly genetic in nature. A large number (~600) of ASD-related genetic variations have been identified (sfari.org), and target gene functions are apparently quite diverse. However, some fall onto common pathways, including synaptic function and chromosome remodeling, suggesting that core mechanisms may exist.

Abnormalities and imbalances in neuronal excitatory and inhibitory synapses have been implicated in diverse neuropsychiatric disorders including autism spectrum disorders (ASDs). Increasing evidence indicates that dysfunction of NMDA receptors (NMDARs) at excitatory synapses is associated with ASDs. In support of this, human ASD-associated genetic variations are found in genes encoding NMDAR subunits. Pharmacological enhancement or suppression of NMDAR function ameliorates ASD symptoms in humans. Animal models of ASD display bidirectional NMDAR dysfunction, and correcting this deficit rescues ASD-like behaviors. These findings suggest that deviation of NMDAR function in either direction contributes to the development of ASDs, and that correcting NMDAR dysfunction has therapeutic potential for ASDs.

Among known synaptic proteins implicated in ASD are metabotropic glutamate receptors (mGluRs). Functional enhancement and suppression of mGluR5 are associated with fragile X syndrome and tuberous sclerosis, respectively, which share autism as a common phenotype. More recently, ionotropic glutamate receptors, namely NMDA receptors (NMDARs) and AMPA receptors (AMPARs), have also been implicated in ASDs. In this review, we will focus on NMDA receptors and summarize evidence supporting the hypothesis that NMDAR dysfunction contributes to ASDs, and, by extension, that correcting NMDAR dysfunction has therapeutic potential for ASDs. ASD-related human NMDAR genetic variants.

Chemokines roles within the hippocampus

Chemokines roles within the hippocampus

IL-1 mediates stress-induced activation of the HPA axis

IL-1 mediates stress-induced activation of the HPA axis

A systemic model of the beneficial role of immune processes in behavioral and neural plasticity

A systemic model of the beneficial role of immune processes in behavioral and neural plasticity

Three Classes of Glutamate Receptors

Three Classes of Glutamate Receptors

Clinical studies on ASDs have identified genetic variants of NMDAR subunit genes. Specifically, de novo mutations have been identified in the GRIN2B gene, encoding the GluN2B subunit. In addition, SNP analyses have linked both GRIN2A (GluN2A subunit) and GRIN2B with ASDs. Because assembled NMDARs contain four subunits, each with distinct properties, ASD-related GRIN2A/ GRIN2B variants likely alter the functional properties of NMDARs and/or NMDAR-dependent plasticity.

Pharmacological modulation of NMDAR function can improve ASD symptoms. D-cycloserine (DCS), an NMDAR agonist, significantly ameliorates social withdrawal and repetitive behavior in individuals with ASD. These results suggest that reduced NMDAR function may contribute to the development of ASDs in humans.

We can divide animal studies into two groups. The first group consists of animals in which NMDAR modulators were shown to normalize both NMDAR dysfunction and ASD-like behaviors, establishing strong association between NMDARs and ASD phenotypes (Fig.). In the second group, NMDAR modulators were shown to rescue ASD-like behaviors, but NMDAR dysfunction and its correction have not been demonstrated.

ASD models with data showing rescue of both NMDAR dysfunction and ASD like behaviors Mice lacking neuroligin-1, an excitatory postsynaptic adhesion molecule, show reduced NMDAR function in the hippocampus and striatum, as evidenced by a decrease in NMDA/AMPA ratio and long-term potentiation (LTP). Neuroligin-1 is thought to enhance synaptic NMDAR function, by directly interacting with and promoting synaptic localization of NMDARs.

Fig not shown.

Bidirectional NMDAR dysfunction in animal models of ASD. Animal models of ASD with bidirectional NMDAR dysfunction can be positioned on either side of an NMDAR function curve. Model animals were divided into two groups.

Group 1: NMDAR modulators normalize both NMDAR dysfunction and ASD-like behaviors (green).

Group 2: NMDAR modulators rescue ASD-like behaviors, but NMDAR dysfunction and its rescue have not been demonstrated (orange). Note that Group 2 animals are tentatively placed on the left-hand side of the slope based on the observed DCS rescue of their ASD-like phenotypes, but the directions of their NMDAR dysfunctions remain to be experimentally determined.

ASD models with data showing rescue of ASD-like behaviors but no demonstrated NMDAR dysfunction

Tbr1 is a transcriptional regulator, one of whose targets is the gene encoding the GluN2B subunit of NMDARs. Mice haploinsufficient for Tbr1 (Tbr1+/-) show structural abnormalities in the amygdala and limited GluN2B induction upon behavioral stimulation. Both systemic injection and local amygdalar infusion of DCS rescue social deficits and impaired associative memory in Tbr1+/- mice. However, reduced NMDAR function and its DCS-dependent correction have not been demonstrated.

Spatial working memory and attention skills are predicted by maternal stress during pregnancy

André Plamondon, Emis Akbari, Leslie Atkinson, Meir Steiner
Early Human Development 91 (2015) 23–29
http://dx.doi.org/10.1016/j.earlhumdev.2014.11.004

Introduction: Experimental evidence in rodents shows that maternal stress during pregnancy (MSDP) negatively impacts spatial learning and memory in the offspring. We aim to investigate the association between MSDP (i.e., life events) and spatial working memory, as well as attention skills (attention shifting and attention focusing), in humans. The moderating roles of child sex, maternal anxiety during pregnancy and postnatal care are also investigated.  Methods: Participants were 236mother–child dyads that were followed from the second trimester of pregnancy until 4 years postpartum. Measurements included questionnaires and independent observations.
Results: MSDP was negatively associated with attention shifting at 18monthswhen concurrent maternal anxiety was low. MSDP was associated with poorer spatial working memory at 4 years of age, but only for boys who experienced poorer postnatal care.
Conclusion: Consistent with results observed in rodents, MSDP was found to be associated with spatial working memory and attention skills. These results point to postnatal care and maternal anxiety during pregnancy as potential targets for interventions that aim to buffer children from the detrimental effects of MSDP.

Acute and massive bleeding from placenta previa and infants’ brain damage

Ken Furuta, Shuichi Tokunaga, Seishi Furukawa, Hiroshi Sameshima
Early Human Development 90 (2014) 455–458
http://dx.doi.org/10.1016/j.earlhumdev.2014.06.002

Background: Among the causes of third trimester bleeding, the impact of placenta previa on cerebral palsy is not well known.
Aims: To clarify the effect ofmaternal bleeding fromplacenta previa on cerebral palsy, and in particular when and how it occurs.
Study design: A descriptive study.
Subjects: Sixty infants born to mothers with placenta previa in our regional population-based study of 160,000 deliveries from 1998 to 2012. Premature deliveries occurring atb26 weeks of gestation and placenta accrete were excluded.
Outcome measures: Prevalence of cystic periventricular leukomalacia (PVL) and cerebral palsy (CP).
Results: Five infants had PVL and 4 of these infants developed CP (1/40,000 deliveries). Acute and massive bleeding (>500 g) within 8 h) occurred at around 30–31 weeks of gestation, and was severe enough to deliver the fetus. None of the 5 infants with PVL underwent antenatal corticosteroid treatment, and 1 infant had mild neonatal hypocapnia with a PaCO2 < 25 mm Hg. However, none of the 5 PVL infants showed umbilical arterial academia with pH < 7.2, an abnormal fetal heart rate monitoring pattern, or neonatal hypotension.
Conclusions: Our descriptive study showed that acute and massive bleeding from placenta previa at around 30 weeks of gestation may be a risk factor for CP, and requires careful neonatal follow-up. The underlying process connecting massive placental bleeding and PVL requires further investigation.

Impact of bilirubin-induced neurologic dysfunction on neurodevelopmental outcomes

Courtney J. Wusthoff, Irene M. Loe
Seminars in Fetal & Neonatal Medicine 20 (2015) 52e57
http://dx.doi.org/10.1016/j.siny.2014.12.003

Extreme neonatal hyperbilirubinemia has long been known to cause the clinical syndrome of kernicterus, or chronic bilirubin encephalopathy (CBE). Kernicterus most usually is characterized by choreoathetoid cerebral palsy (CP), impaired upward gaze, and sensorineural hearing loss, whereas cognition is relatively spared. The chronic condition of kernicterus may be, but is not always, preceded in the acute stage by acute bilirubin encephalopathy (ABE). This acute neonatal condition is also due to hyperbilirubinemia, and is characterized by lethargy and abnormal behavior, evolving to frank neonatal encephalopathy, opisthotonus, and seizures. Less completely defined is the syndrome of bilirubin-induced neurologic dysfunction (BIND).

Bilirubin-induced neurologic dysfunction (BIND) is the constellation of neurologic sequelae following milder degrees of neonatal hyperbilirubinemia than are associated with kernicterus. Clinically, BIND may manifest after the neonatal period as developmental delay, cognitive impairment, disordered executive function, and behavioral and psychiatric disorders. However, there is controversy regarding the relative contribution of neonatal hyperbilirubinemia versus other risk factors to the development of later neurodevelopmental disorders in children with BIND. In this review, we focus on the empiric data from the past 25 years regarding neurodevelopmental outcomes and BIND, including specific effects on developmental delay, cognition, speech and language development, executive function, and the neurobehavioral disorders, such as attention deficit/hyperactivity disorder and autism.

As noted in a technical report by the American Academy of Pediatrics Subcommittee on Hyperbilirubinemia, “it is apparent that the use of a single total serum bilirubin level to predict long-term outcomes is inadequate and will lead to conflicting results”. As described above, this has certainly been the case in research to date. To clarify how hyperbilirubinemia influences neurodevelopmental outcome, more sophisticated consideration is needed both of how to assess bilirubin exposure leading to neurotoxicity, and of those comorbid conditions which may lower the threshold for brain injury.

For example, premature infants are known to be especially susceptible to bilirubin neurotoxicity, with kernicterus reported following TB levels far lower than the threshold expected in term neonates. Similarly, among extremely preterm neonates, BBC is proportional to gestational age, meaning that the most premature infants have the highest UB, even for similar TB levels. Thus, future studies must be adequately powered to examine preterm infants separately from term infants, and should consider not just peak TB, but also BBC, as independent variables in neonates with hyperbilirubinemia. Similarly, an analysis by the NICHD NRN found that, among ELBW infants, higher UB levels were associated with a higher risk of death or NDI. However, increased TB levels were only associated with death or NDI in unstable infants. Again, UB or BBC appeared to be more useful than TB.

Are the neuromotor disabilities of bilirubin-induced neurologic dysfunction disorders related to the cerebellum and its connections?

Jon F. Watchko, Michael J. Painter, Ashok Panigrahy
Seminars in Fetal & Neonatal Medicine 20 (2015) 47e51
http://dx.doi.org/10.1016/j.siny.2014.12.004

Investigators have hypothesized a range of subcortical neuropathology in the genesis of bilirubin induced neurologic dysfunction (BIND). The current review builds on this speculation with a specific focus on the cerebellum and its connections in the development of the subtle neuromotor disabilities of BIND. The focus on the cerebellum derives from the following observations:
(i) the cerebellum is vulnerable to bilirubin-induced injury; perhaps the most vulnerable region within the central nervous system;
(ii) infants with cerebellar injury exhibit a neuromotor phenotype similar to BIND; and                                                       (iii) the cerebellum has extensive bidirectional circuitry projections to motor and non-motor regions of the brain-stem and cerebral cortex that impact a variety of neurobehaviors.
Future study using advanced magnetic resonance neuroimaging techniques have the potential to shed new insights into bilirubin’s effect on neural network topology via both structural and functional brain connectivity measurements.

Bilirubin-induced neurologic damage is most often thought of in terms of severe adverse neuromotor (dystonia with or without athetosis) and auditory (hearing impairment or deafness) sequelae. Observed together, they comprise the classic neurodevelopmental phenotype of chronic bilirubin encephalopathy or kernicterus, and may also be seen individually as motor or auditory predominant subtypes. These injuries reflect both a predilection of bilirubin toxicity for neurons (relative to glial cells) and the regional topography of bilirubin-induced neuronal damage characterized by prominent involvement of the globus pallidus, subthalamic nucleus, VIII cranial nerve, and cochlear nucleus.

It is also asserted that bilirubin neurotoxicity may be associated with other less severe neurodevelopmental disabilities, a condition termed “subtle kernicterus” or “bilirubin-induced neurologic dysfunction” (BIND). BIND is defined by a constellation of “subtle neurodevelopmental disabilities without the classical findings of kernicterus that, after careful evaluation and exclusion of other possible etiologies, appear to be due to bilirubin neurotoxicity”. These purportedly include:

(i) mild-to-moderate disorders of movement (e.g., incoordination, clumsiness, gait abnormalities, disturbances in static and dynamic balance, impaired fine motor skills, and ataxia);                                                                                             (ii) disturbances in muscle tone; and
(iii) altered sensorimotor integration. Isolated disturbances of central auditory processing are also included in the spectrum of BIND.

  • Cerebellar vulnerability to bilirubin-induced injury
  • Cerebellar injury phenotypes and BIND
  • Cerebellar projections
Transverse section of cerebellum and brainstem

Transverse section of cerebellum and brainstem

Transverse section of cerebellum and brain-stem from a 34 gestational-week premature kernicteric infant formalin-fixed for two weeks. Yellow staining is evident in the cerebellar dentate nuclei (upper arrow) and vestibular nuclei at the pontomedullary junction (lower arrowhead). Photo is courtesy of Mahmdouha Ahdab-Barmada and reprinted with permission from Taylor-Francis Group (Ahdab Barmada M. The neuropathology of kernicterus: definitions and debate. In: Maisel MJ, Watchko JF editors. Neonatal jaundice. Amsterdam: Harwood Academic Publishers; 2000. p. 75e88

Whether cerebellar injury is primal or an integral part of disturbed neural circuitry in bilirubin-induced CNS damage is unclear. Movement disorders, however, are increasingly recognized to arise from abnormalities of neuronal circuitry rather than localized, circumscribed lesions. The cerebellum has extensive bidirectional circuitry projections to an array of brainstem nuclei and the cerebral cortex that modulate and refine motor activities. In this regard, the cerebellum is characteristically subdivided into three lobes based on neuroanatomic and phylogenetic criteria as well as by their primary afferent and efferent connections. They include:
(i) flocculonodular lobe (archicerebellum);
(ii) anterior lobe (paleocerebellum); and
(iii) posterior lobe (neocerebellum).

The archicerebellum, the oldest division phylogenically, receives extensive input from the vestibular system and is therefore also known as the vestibulocerebellum and is important for equilibrium control. The paleocerebellum, also a primitive region, receives extensive somatosensory input from the spinal cord, including the anterior and posterior spinocerebellar pathways that convey unconscious proprioception, and is therefore also known as the spinocerebellum. The neocerebellum is the most recently evolved region, receives most of the input from the cerebral cortex, and is thus termed the cerebrocerebellum. This area has greatly expanded in association with the extensive development of the cerebral cortex in mammals and especially primates. To cause serious longstanding dysfunction, cerebellar injury must typically involve the deep cerebellar nuclei and their projections.

Schematic of the bidirectional connectivity between the cerebellum and other

Schematic of the bidirectional connectivity between the cerebellum and other

Schematic of the bidirectional connectivity between the cerebellum and other brain regions including the cerebral cortex. Most cerebro-cerebellar afferent projections pass through the basal (anterior or ventral) pontine nuclei and intermediate cerebellar peduncle, whereas most cerebello-cerebral efferent projections pass through the dentate and ventrolateral thalamic nuclei. DCN, deep cerebellar nuclei; RN, red nucleus; ATN, anterior thalamic nucleus; PFC, prefrontal cortex; MC, motor cortex; PC, parietal cortex; TC, temporal cortex; STN, subthalamic nucleus; APN, anterior pontine nuclei. Reprinted under the terms of the Creative Commons Attribution License from D’Angelo E, Casali S. Seeking a unified framework for cerebellar function and dysfunction: from circuit to cognition. Front Neural Circuits 2013; 6:116.

Given the vulnerability of the cerebellum to bilirubin-induced injury, cerebellar involvement should also be evident in classic kernicterus, contributing to neuromotor deficits observed therein. It is of interest, therefore, that cerebellar damage may play a role in the genesis of bilirubin-induced dystonia, a prominent neuromotor feature of chronic bilirubin encephalopathy in preterm and term neonates alike. This complex movement disorder is characterized by involuntary sustained muscle contractions that result in abnormal position and posture. Moreover, dystonia that is brief in duration results in chorea, and, if brief and repetitive, leads to athetosis ‒ conditions also classically observed in kernicterus. Recent evidence suggests that dystonic movements may depend on disruption of both basal ganglia and cerebellar neuronal networks, rather than isolated dysfunction of only one motor system.

Dystonia is also a prominent feature in Gunn rat pups and neonatal Ugt1‒/‒-deficient mice both robust models of kernicterus. The former is used as an experimental model of dystonia. Although these models show basal ganglia injury, the sine qua non of bilirubin-induced murine neuropathology is cerebellar damage and resultant cerebellar hypoplasia.

Studies are needed to define more precisely the motor network abnormalities in kernicterus and BIND. Magnetic resonance imaging (MRI) has been widely used in evaluating infants at risk for bilirubin-induced brain injury using conventional structural T1-and T2-weighted imaging. Infants with chronic bilirubin encephalopathy often demonstrate abnormal bilateral, symmetric, high-signal intensity on T2-weighted MRI of the globus pallidus and subthalamic nucleus, consistent with the neuropathology of kernicterus. Early postnatal MRI of at-risk infants, although frequently showing increased T1-signal in these regions, may give false-positive findings due to the presence of myelin in these structures.

Diffusion tensor imaging and tractography could be used to delineate long-term changes involving specific white matter pathways, further elucidating the neural basis of long-term disability in infants and children with chronic bilirubin encephalopathy and BIND. It will be equally valuable to use blood oxygen level-dependent (BOLD) “resting state” functional MRI to study intrinsic connectivity in order to identify vulnerable brain networks in neonates with kernicterus and BIND. Structural networks of the CNS (connectome) and functional network topology can be characterized in infants with kernicterus and BIND to determine disease-related pattern(s) with respect to both long- and short-range connectivity. These findings have the potential to shed novel insights into the pathogenesis of these disorders and their impact on complex anatomical connections and resultant functional deficits.

Audiologic impairment associated with bilirubin-induced neurologic damage

Cristen Olds, John S. Oghalai
Seminars in Fetal & Neonatal Medicine 20 (2015) 42e46
http://dx.doi.org/10.1016/j.siny.2014.12.006

Hyperbilirubinemia affects up to 84% of term and late preterm infants in the first week of life. The elevation of total serum/plasma bilirubin (TB) levels is generally mild, transitory, and, for most children, inconsequential. However, a subset of infants experiences lifelong neurological sequelae. Although the prevalence of classic kernicterus has fallen steadily in the USA in recent years, the incidence of jaundice in term and premature infants has increased, and kernicterus remains a significant problem in the global arena. Bilirubin-induced neurologic dysfunction (BIND) is a spectrum of neurological injury due to acute or sustained exposure of the central nervous system(CNS) to bilirubin. The BIND spectrum includes kernicterus, acute bilirubin encephalopathy, and isolated neural pathway dysfunction.

Animal studies have shown that unconjugated bilirubin passively diffuses across cell membranes and the blood‒brain barrier (BBB), and bilirubin not removed by organic anion efflux pumps accumulates within the cytoplasm and becomes toxic. Exposure of neurons to bilirubin results in increased oxidative stress and decreased neuronal proliferation and presynaptic neuro-degeneration at central glutaminergic synapses. Furthermore, bilirubin administration results in smaller spiral ganglion cell bodies, with decreased cellular density and selective loss of large cranial nerve VIII myelinated fibers. When exposed to bilirubin, neuronal supporting cells have been found to secrete inflammatory markers, which contribute to increased BBB permeability and bilirubin loading.

The jaundiced Gunn rat is the classic animal model of bilirubin toxicity. It is homozygous for a premature stop codon within the gene for UDP-glucuronosyltransferase family 1 (UGT1). The resultant gene product has reduced bilirubin-conjugating activity, leading to a state of hyperbilirubinemia. Studies with this rat model have led to the concept that impaired calcium homeostasis is an important mechanism of neuronal toxicity, with reduced expression of calcium-binding proteins in affected cells being a sensitive index of bilirubin-induced neurotoxicity. Similarly, application of bilirubin to cultured auditory neurons from brainstem cochlear nuclei results in hyperexcitability and excitotoxicity.

The auditory pathway and normal auditory brainstem response (ABR).

The auditory pathway and normal auditory brainstem response (ABR).

The auditory pathway and normal auditory brain-stem response (ABR). The ipsilateral (green) and contralateral (blue) auditory pathways are shown, with structures that are known to be affected by hyperbilirubinemia highlighted in red. Roman numerals in parentheses indicate corresponding waves in the normal human ABR (inset). Illustration adapted from the “Ear Anatomy” series by Robert Jackler and Christine Gralapp, with permission.

Bilirubin-induced neurologic dysfunction (BIND)

Vinod K. Bhutani, Ronald Wong
Seminars in Fetal & Neonatal Medicine 20 (2015) 1
http://dx.doi.org/10.1016/j.siny.2014.12.010

Beyond the traditional recognized areas of fulminant injury to the globus pallidus as seen in infants with kernicterus, other vulnerable areas include the cerebellum, hippocampus, and subthalamic nuclear bodies as well as certain cranial nerves. The hippocampus is a brain region that is particularly affected by age related morphological changes. It is generally assumed that a loss in hippocampal volume results in functional deficits that contribute to age-related cognitive deficits. Lower grey matter volumes within the limbic-striato-thalamic circuitry are common to other etiological mechanisms of subtle neurologic injury. Lower grey matter volumes in the amygdala, caudate, frontal and medial gyrus are found in schizophrenia and in the putamen in autism. Thus, in terms of brain volumetrics, schizophrenia and autism spectrum disorders have a clear degree of overlap that may reflect shared etiological mechanisms. Overlap with injuries observed in infants with BIND raises the question about how these lesions are arrived at in the context of the impact of common etiologies.

Stress-induced perinatal and transgenerational epigenetic programming of brain development and mental health

Olena Babenko, Igor Kovalchuk, Gerlinde A.S. Metz
Neuroscience and Biobehavioral Reviews 48 (2015) 70–91
http://dx.doi.org/10.1016/j.neubiorev.2014.11.013

Research efforts during the past decades have provided intriguing evidence suggesting that stressful experiences during pregnancy exert long-term consequences on the future mental wellbeing of both the mother and her baby. Recent human epidemiological and animal studies indicate that stressful experiences in utero or during early life may increase the risk of neurological and psychiatric disorders, arguably via altered epigenetic regulation. Epigenetic mechanisms, such as miRNA expression, DNA methylation, and histone modifications are prone to changes in response to stressful experiences and hostile environmental factors. Altered epigenetic regulation may potentially influence fetal endocrine programming and brain development across several generations. Only recently, however, more attention has been paid to possible transgenerational effects of stress. In this review we discuss the evidence of transgenerational epigenetic inheritance of stress exposure in human studies and animal models. We highlight the complex interplay between prenatal stress exposure, associated changes in miRNA expression and DNA methylation in placenta and brain and possible links to greater risks of schizophrenia, attention deficit hyperactivity disorder, autism, anxiety- or depression-related disorders later in life. Based on existing evidence, we propose that prenatal stress, through the generation of epigenetic alterations, becomes one of the most powerful influences on mental health in later life. The consideration of ancestral and prenatal stress effects on lifetime health trajectories is critical for improving strategies that support healthy development and successful aging.

Sensitive time-windows for susceptibility in neurodevelopmental disorders

Rhiannon M. Meredith, Julia Dawitz and Ioannis Kramvis
Trends in Neurosciences, June 2012; 35(6): 335-344
http://dx.doi.org:/10.1016/j.tins.2012.03.005

Many neurodevelopmental disorders (NDDs) are characterized by age-dependent symptom onset and regression, particularly during early postnatal periods of life. The neurobiological mechanisms preceding and underlying these developmental cognitive and behavioral impairments are, however, not clearly understood. Recent evidence using animal models for monogenic NDDs demonstrates the existence of time-regulated windows of neuronal and synaptic impairments. We propose that these developmentally-dependent impairments can be unified into a key concept: namely, time-restricted windows for impaired synaptic phenotypes exist in NDDs, akin to critical periods during normal sensory development in the brain. Existence of sensitive time-windows has significant implications for our understanding of early brain development underlying NDDs and may indicate vulnerable periods when the brain is more susceptible to current therapeutic treatments.

Fig (not shown)

Misregulated mechanisms underlying spine morphology in NDDs. Several proteins implicated in monogenic NDDs (highlighted in red) are linked to the regulation of the synaptic cytoskeleton via F-actin through different Rho-mediated signaling pathways (highlighted in green). Mutations in OPHN1, TSC1/2, FMRP, p21-activated kinase (PAK) are directly linked to human NDDs of intellectual disability. For instance, point mutations in OPHN1 and a PAK isoform are linked to non-syndromic mental retardation, whereas mutations or altered expression of TSC1/2 and FMRP are linked to TSC and FXS, respectively. Cytoplasmic interacting protein (CYFIP) and LIM-domain kinase 1 (LIMK1) are known to interact with FMRP and PAK, respectively [105]. LIMK1 is one of many dysregulated proteins contributing to the NDD Williams syndrome. Mouse models are available for all highlighted (red) proteins and reveal specific synaptic and behavioral deficits. Local protein synthesis in synapses, dendrites and glia is also regulated by proteins such as TSC1/2 and the FMRP/CYFIP complex. Abbreviations: 4EBP, 4E binding protein; eIF4E, eukaryotic translation initiation factor 4E.

Fig (not shown)

Sensitive time-windows, synaptic phenotypes and NDD gene targets. Sensitive time-windows exist in neural circuits, during which gene targets implicated in NDDs are normally expressed. Misregulation of these genes can affect multiple synaptic phenotypes during a restricted developmental period. The effect upon synaptic phenotypes is dependent upon the temporal expression of these NDD genes and their targets. (a) Expression outside a critical period of development will have no effect upon synaptic phenotypes. (b,c) A temporal expression pattern that overlaps with the onset (b) or closure (c) of a known critical period can alter the synaptic phenotype during that developmental time-window.

Outstanding questions

(1) Can treatment at early presymptomatic stages in animal models for NDDs prevent or ease the later synaptic, neuronal, and behavioral impairments?

(2) Are all sensory critical periods equally misregulated in mouse models for a specific NDD? Are there different susceptibilities for auditory, visual and somatosensory neurocircuits that reflect the degree of impairments observed in patients?

(3) If one critical period is missed or delayed during formation of a layer-specific connection in a network, does the network overcome this misregulated connectivity or plasticity window?

(4) In monogenic NDDs, does the severity of misregulating one particular time-window for synaptic establishment during development correlate with the importance of that gene for that synaptic circuit?

(5) Why do critical periods close in brain development?

(6) What underlies the regression of some altered synaptic phenotypes in Fmr1-KO mice?

(7) Can the concept of susceptible time-windows be applied to other NDDs, including schizophrenia and Tourette’s syndrome?

Cardiovascular

Cardiac output monitoring in newborns

Willem-Pieter de Boode
Early Human Development 86 (2010) 143–148
http://dx.doi.org:/10.1016/j.earlhumdev.2010.01.032

There is an increased interest in methods of objective cardiac output measurement in critically ill patients. Several techniques are available for measurement of cardiac output in children, although this remains very complex in newborns. Cardiac output monitoring could provide essential information to guide hemodynamic management. An overview is given of various methods of cardiac output monitoring with advantages and major limitations of each technology together with a short explanation of the basic principles.

Fick principle

According to the Fick principle the volume of blood flow in a given period equals the amount of substance entering the blood stream in the same period divided by the difference in concentrations of the substrate upstream respectively downstream to the point of entry in the circulation. This substance can be oxygen (O2-Fick) or carbon dioxide (CO2-FICK), so cardiac output can be calculated by dividing measured pulmonary oxygen uptake by the arteriovenous oxygen concentration difference. The direct O2-Fick method is regarded as gold standard in cardiac output monitoring in a research setting, despite its limitations. When the Fick principle is applied for carbon dioxide (CO2 Fick), the pulmonary carbon dioxide exchange is divided by the venoarterial CO2 concentration difference to calculate cardiac output.

In the modified CO2 Fick method pulmonary CO2 exchange is measured at the endotracheal tube. Measurement of total CO2 concentration in blood is more complex and simultaneous sampling of arterial and central venous blood is required. However, frequent blood sampling will result in an unacceptable blood loss in the neonatal population.

Blood flow can be calculated if the change in concentration of a known quantity of injected indicator is measured in time distal to the point of injection, so an indicator dilution curve can be obtained. Cardiac output can then be calculated with the use of the Stewart–Hamilton equation. Several indicators are used, such as indocyanine green, Evans blue and brilliant red in dye dilution, cold solutions in thermodilution, lithium in lithium dilution, and isotonic saline in ultrasound dilution.

Cardiovascular adaptation to extra uterine life

Alice Lawford, Robert MR Tulloh
Paediatrics And Child Health 2014; 25(1): 1-6.

The adaptation to extra uterine life is of interest because of its complexity and the ability to cause significant health concerns. In this article we describe the normal changes that occur and the commoner abnormalities that are due to failure of normal development and the effect of congenital cardiac disease. Abnormal development may occur as a result of problems with the mother, or with the fetus before birth. After birth it is essential to determine whether there is an underlying abnormality of the fetal pulmonary or cardiac development and to determine the best course of management of pulmonary hypertension or congenital cardiac disease. Causes of underdevelopment, maldevelopment and maladaptation are described as are the causes of critical congenital heart disease. The methods of diagnosis and management are described to allow the neonatologist to successfully manage such newborns.

Fetal vascular structures that exist to direct blood flow

Fetal structure Function
Arterial duct Connects pulmonary artery to the aorta and shunts blood right to left; diverting flow away from fetal lungs
Foramen ovale Opening between the two atria thatdirects blood flow returning to right

atrium through the septal wall into the left atrium bypassing lungs

Ductus venosus Receives oxygenated blood fromumbilical vein and directs it to the

inferior vena cava and right atrium

Umbilical arteries Carrying deoxygenated blood fromthe fetus to the placenta
Umbilical vein Carrying oxygenated blood from theplacenta to the fetus

Maternal causes of congenital heart disease

Maternal disorders rubella, SLE, diabetes mellitus
Maternal drug use Warfarin, alcohol
Chromosomal abnormality Down, Edward, Patau, Turner, William, Noonan

 

Fetal and Neonatal Circulation  The fetal circulation is specifically adapted to efficiently exchange gases, nutrients, and wastes through placental circulation. Upon birth, the shunts (foramen ovale, ductus arteriosus, and ductus venosus) close and the placental circulation is disrupted, producing the series circulation of blood through the lungs, left atrium, left ventricle, systemic circulation, right heart, and back to the lungs.

Clinical monitoring of systemic hemodynamics in critically ill newborns

Willem-Pieter de Boode
Early Human Development 86 (2010) 137–141
http://dx.doi.org:/10.1016/j.earlhumdev.2010.01.031

Circulatory failure is a major cause of mortality and morbidity in critically ill newborn infants. Since objective measurement of systemic blood flow remains very challenging, neonatal hemodynamics is usually assessed by the interpretation of various clinical and biochemical parameters. An overview is given about the predictive value of the most used indicators of circulatory failure, which are blood pressure, heart rate, urine output, capillary refill time, serum lactate concentration, central–peripheral temperature difference, pH, standard base excess, central venous oxygen saturation and color.

Key guidelines

➢ The clinical assessment of cardiac output by the interpretation of indirect parameters of systemic blood flow is inaccurate, irrespective of the level of experience of the clinician

➢ Using blood pressure to diagnose low systemic blood flow will consequently mean that too many patients will potentially be undertreated or overtreated, both with substantial risk of adverse effects and iatrogenic damage.

➢ Combining different clinical hemodynamic parameters enhances the predictive value in the detection of circulatory failure, although accuracy is still limited.

➢ Variation in time (trend monitoring) might possibly be more informative than individual, static values of clinical and biochemical parameters to evaluate the adequacy of neonatal circulation.

Monitoring oxygen saturation and heart rate in the early neonatal period

J.A. Dawson, C.J. Morley
Seminars in Fetal & Neonatal Medicine 15 (2010) 203e207
http://dx.doi.org:/10.1016/j.siny.2010.03.004

Pulse oximetry is commonly used to assist clinicians in assessment and management of newly born infants in the delivery room (DR). In many DRs, pulse oximetry is now the standard of care for managing high risk infants, enabling immediate and dynamic assessment of oxygenation and heart rate. However, there is little evidence that using pulse oximetry in the DR improves short and long term outcomes. We review the current literature on using pulse oximetry to measure oxygen saturation and heart rate and how to apply current evidence to management in the DR.

Practice points

  • Understand how SpO2 changes in the first minutes after birth.
  • Apply a sensor to an infant’s right wrist as soon as possible after birth.
  • Attach sensor to infant then to oximeter cable.
  • Use two second averaging and maximum sensitivity.

Using pulse oximetry assists clinicians:

  1. Assess changes in HR in real time during transition.
  2. Assess oxygenation and titrate the administration of oxygen to maintain oxygenation within the appropriate range for SpO2 during the first minutes after birth.

Research directions

  • What are the appropriate centiles to target during the minutes after birth to prevent hypoxia and hyperoxia: 25th to 75th, or 10th to 90th, or just the 50th (median)?
  • Can the inspired oxygen be titrated against the SpO2 to keep the SpO2 in the ‘normal range’?
  • Does the use of centile charts in the DR for HR and oxygen saturation reduce the rate of hyperoxia when infants are treated with oxygen.
  • Does the use of pulse oximetry immediately after birth improve short term outcomes, e.g. efficacy of immediate respiratory support, intubation rates in the DR, percentage of inspired oxygen, rate of use of adrenalin or chest compressions, duration of hypoxia/hyperoxia and bradycardia.
  • Does the use of pulse oximetry in the DR improve short term respiratory and long term neurodevelopmental outcomes for preterm infants, e.g. rate of intubation, use of surfactant, and duration of ventilation, continuous positive airway pressure, or supplemental oxygen?
  • Can all modern pulse oximeters be used effectively in the DR or do some have a longer delay before giving an accurate signal and more movement artefact?
  • Would a longer averaging time result in more stable data?

Peripheral haemodynamics in newborns: Best practice guidelines

Michael Weindling, Fauzia Paize
Early Human Development 86 (2010) 159–165
http://dx.doi.org:/10.1016/j.earlhumdev.2010.01.033

Peripheral hemodynamics refers to blood flow, which determines oxygen and nutrient delivery to the tissues. Peripheral blood flow is affected by vascular resistance and blood pressure, which in turn varies with cardiac function. Arterial oxygen content depends on the blood hemoglobin concentration (Hb) and arterial pO2; tissue oxygen delivery depends on the position of the oxygen-dissociation curve, which is determined by temperature and the amount of adult or fetal hemoglobin. Methods available to study tissue perfusion include near-infrared spectroscopy, Doppler flowmetry, orthogonal polarization spectral imaging and the peripheral perfusion index. Cardiac function, blood gases, Hb, and peripheral temperature all affect blood flow and oxygen extraction. Blood pressure appears to be less important. Other factors likely to play a role are the administration of vasoactive medications and ventilation strategies, which affect blood gases and cardiac output by changing the intrathoracic pressure.

graphic

NIRS with partial venous occlusion to measure venous oxygen saturation

NIRS with partial venous occlusion to measure venous oxygen saturation

NIRS with partial venous occlusion to measure venous oxygen saturation. Taken from Yoxall and Weindling

Schematic representation of the biphasic relationship between oxygen delivery and oxygen consumption in tissue

Schematic representation of the biphasic relationship between oxygen delivery and oxygen consumption in tissue

graphic

Schematic representation of the biphasic relationship between oxygen delivery and oxygen consumption in tissue.  (a) oxygen delivery (DO2). (b) As DO2 decreases, VO2 is dependent on DO2. The slope of the line indicates the FOE, which in this case is about 0.50. (c) The slope of the line indicates the FOE in the normal situation where oxygenation is DO2 independent, usually < 0.35

The oxygen-dissociation curve

The oxygen-dissociation curve

graphic

The oxygen-dissociation curve

Considerable information about the response of the peripheral circulation has been obtained using NIRS with venous occlusion. Although these measurements were validated against blood co-oximetry in human adults and infants, they can only be made intermittently by a trained operator and are thus not appropriate for general clinical use. Further research is needed to find other better measures of peripheral perfusion and oxygenation which may be easily and continuously monitored, and which could be useful in a clinical setting.

Peripheral oxygenation and management in the perinatal period

Michael Weindling
Seminars in Fetal & Neonatal Medicine 15 (2010) 208e215
http://dx.doi.org:/10.1016/j.siny.2010.03.005

The mechanisms for the adequate provision of oxygen to the peripheral tissues are complex. They involve control of the microcirculation and peripheral blood flow, the position of the oxygen dissociation curve including the proportion of fetal and adult hemoglobin, blood gases and viscosity. Systemic blood pressure appears to have little effect, at least in the non-shocked state. The adequate delivery of oxygen (DO2) depends on consumption (VO2), which is variable. The balance between VO2 and DO2 is given by fractional oxygen extraction (FOE ¼ VO2/DO2). FOE varies from organ to organ and with levels of activity. Measurements of FOE for the whole body produce a range of about 0.15-0.33, i.e. the body consumes 15-33% of oxygen transported.

Fig (not shown)

Biphasic relationship between oxygen delivery (DO2) and oxygen consumption (VO2) in tissue. Dotted lines show fractional oxygen extraction (FOE). ‘A’ indicates the normal situation when VO2 is independent ofDO2 and FOE is about 0.30. AsDO2 decreases in the direction of the arrow, VO2 remains independent of DO2 until the critical point is reached at ‘B’; in this illustration, FOE is about 0.50. The slope of the dotted line indicates the FOE (¼ VO2/DO2), which increases progressively as DO2 decreases.

Relationship between haemoglobin F fraction (HbF) and peripheral fractional oxygen extraction

Relationship between haemoglobin F fraction (HbF) and peripheral fractional oxygen extraction

Graphic
(A)Relationship between haemoglobin F fraction (HbF) and peripheral fractional oxygen extraction in anaemic and control infants. (From Wardle et al.)  (B) HbF synthesis and concentration. (From Bard and Widness.) (C) Oxygen dissociation curve.

Peripheral fractional oxygen extraction in babies

Peripheral fractional oxygen extraction in babies

graphic

Peripheral fractional oxygen extraction in babies with asymptomatic or symptomatic anemia compared to controls. Bars represent the median for each group. (From Wardle et al.)

Practice points

  • Peripheral tissue DO2 is complex: cardiac function, blood gases, Hb concentration and the proportion of HbF, and peripheral temperature all play a part in determining blood flow and oxygen extraction in the sick, preterm infant. Blood pressure appears to be less important.
  • Other factors likely to play a role are the administration of vasoactive medications and ventilation strategies, which affect blood gases and cardiac output by changing intrathoracic pressure.
  • Central blood pressure is a poor surrogate measurement for the adequacy of DO2 to the periphery. Direct measurement, using NIRS, laser Doppler flowmetry or other means, may give more useful information.
  • Reasons for total hemoglobin concentration (Hb) being a relatively poor indicator of the adequacy of the provision of oxygen to the tissues:
  1. Hb is only indirectly related to red blood cell volume, which may be a better indicator of the body’s oxygen delivering capacity.
  2. Hb-dependent oxygen availability depends on the position of the oxygen-hemoglobin dissociation curve.
  3. An individual’s oxygen requirements vary with time and from organ to organ. This means that DO2 also needs to vary.
  4. It is possible to compensate for a low Hb by increasing cardiac output and ventilation, and so the ability to compensate for anemia depends on an individual’s cardio-respiratory reserve as well as Hb.
  5. The normal decrease of Hb during the first few weeks of life in both full-term and preterm babies usually occurs without symptoms or signs of anemia or clinical consequences.

The relationship between VO2 and DO2 is complex and various factors need to be taken into account, including the position of the oxygen dissociation curve, determined by the proportion of HbA and HbF, temperature and pH. Furthermore, diffusion of oxygen from capillaries to the cell depends on the oxygen tension gradient between erythrocytes and the mitochondria, which depends on microcirculatory conditions, e.g. capillary PO2, distance of the cell from the capillary (characterized by intercapillary distances) and the surface area of open capillaries. The latter can change rapidly, for example, in septic shock where arteriovenous shunting occurs associated with tissue hypoxia in spite of high DO2 and a low FOE.

Changes in local temperature deserve particular consideration. When the blood pressure is low, there may be peripheral vasoconstriction with decreased local perfusion and DO2. However, the fall in local tissue temperature would also be expected to be associated with a decreased metabolic rate and a consequent decrease in VO2. Thus a decreased DO2 may still be appropriate for tissue needs.

Pulmonary

Accurate Measurements of Oxygen Saturation in Neonates: Paired Arterial and Venous Blood Analyses

Shyang-Yun Pamela K. Shiao
Newborn and Infant Nurs Rev,  2005; 5(4): 170–178
http://dx.doi.org:/10.1053/j.nainr.2005.09.001

Oxygen saturation (So2) measurements (functional measurement, So2; and fractional measurement, oxyhemoglobin [Hbo2]) and monitoring are commonly investigated as a method of assessing oxygenation in neonates. Differences exist between the So2 and Hbo2 when blood tests are performed, and clinical monitors indicate So2 values. Oxyhemoglobin will decrease with the increased levels of carbon monoxide hemoglobin (Hbco) and methemo-globin (MetHb), and it is the most accurate measurements of oxygen (O2) association of hemoglobin (Hb). Pulse oximeter (for pulse oximetry saturation [Spo2] measurement) is commonly used in neonates. However, it will not detect the changes of Hb variations in the blood for accurate So2 measurements. Thus, the measurements from clinical oximeters should be used with caution. In neonates, fetal hemoglobin (HbF) accounts for most of the circulating Hb in their blood. Fetal hemoglobin has a high O2 affinity, thus releases less O2 to the body tissues, presenting a left-shifted Hbo2 dissociation curve.5,6 To date, however, limited data are available with HbF correction, for accurate arterial and venous (AV) So2 measurements (arterial oxygen saturation [Sao2] and venous oxygen saturation [Svo2]) in neonates, using paired AV blood samples.

In a study of critically ill adult patients, increased pulmonary CO production and elevation in arterial Hbco but not venous Hbco were documented by inflammatory stimuli inducing pulmonary heme oxygenase–1. In normal adults, venous Hbco level might be slightly higher than or equal to arterial Hbco because of production of CO by enzyme heme oxygenase–2, which is predominantly produced in the liver and spleen. However, hypoxia or pulmonary inflammation could induce heme oxygenase–1 to increase endogenous CO, thus elevating pulmonary arterial and systemic arterial Hbco levels in adults. Both endogenous and exogenous CO can suppress proliferation of pulmonary smooth muscles, a significant consideration for the prevention of chronic lung diseases in newborns. Despite these considerations, a later study in healthy adults indicated that the AV differences in Hbco were from technical artifacts and perhaps from inadequate control of different instruments. Thus, further studies are needed to provide more definitive answers for the AV differences of Hbco for adults and neonates with acute and chronic lung diseases.

Methemoglobin is an indicator of Hb oxidation and is essential for accurate measurement of Hbo2, So2, and oxygenation status. No evidence exists to show the AV MetHb difference, although this difference was elucidated with the potential changes of MetHb with different O2 levels.  Methemoglobin can be increased with nitric oxide (NO) therapy, used in respiratory distress syndrome (RDS) to reduce pulmonary hypertension and during heart surgery. Nitric oxide, in vitro, is an oxidant of Hb, with increased O2 during ischemia reperfusion. In hypoxemic conditions in vivo, nitrohemoglobin is a product generated by vessel responsiveness to nitrovasodilators. Nitro-hemoglobin can be spontaneously reversible in vivo, requiring no chemical agents or reductase. However, when O2 levels were increased experimentally in vitro following acidic conditions (pH 6.5) to simulate reperfusion conditions, MetHb levels were increased for the hemolysates (broken red cells). Nitrite-induced oxidation of Hb was associated with an increase in red blood cell membrane rigidity, thus contributing to Hb breakdown. A newer in vitro study of whole blood cells, however, concluded that MetHb formation is not dependent on increased O2 levels. Additional studies are needed to examine in vivo reperfusion of O2 and MetHb effects.

Purpose: The aim of this study was to examine the accuracy of arterial oxygen saturation (Sao2) and venous oxygen saturation (Svo2) with paired arterial and venous (AV) blood in relation to pulse oximetry saturation (Spo2) and oxyhemoglobin (Hbo2) with fetal hemoglobin determination, and their Hbo2 dissociation curves. Method: Twelve preterm neonates with gestational ages ranging from 27 to 34 weeks at birth, who had umbilical AV lines inserted, were investigated. Analyses were performed with 37 pairs of AV blood samples by using a blood volume safety protocol. Results: The mean differences between Sao2 and Svo2, and AV Hbo2 were both 6 percent (F6.9 and F6.7 percent, respectively), with higher Svo2 than those reported for adults. Biases were 2.1 – 0.49 for Sao2, 2.0 – 0.44 for Svo2, and 3.1 – 0.45 for Spo2, compared against Hbo2. With left-shifted Hbo2 dissociation curves in neonates, for the critical values of oxygen tension values between 50 and 75 millimeters of mercury, Hbo2 ranged from 92 to 93.4 percent; Sao2 ranged from 94.5 to 95.7 percent; and Spo2 ranged from 93.7 to 96.3 percent (compared to 85–94 percent in healthy adults). Conclusions: In neonates, both left-shifted Hbo2 dissociation curve and lower AV differences of oxygen saturation measurements indicated low flow of oxygen to the body tissues. These findings demonstrate the importance of accurate assessment of oxygenation statues in neonates.

In these neonates, the mean AV blood differences for both So2 and Hbo2 were about 6 percent, which was much lower than those reported for healthy adults (23 percent) for O2 supply and demand. In addition, with very high levels of HbF releasing less O2 to the body tissue, the results of blood analyses are worrisome for these critically ill neonates for low systemic oxygen states.  O’Connor and Hall determined AV So2 in neonates without HbF determination. Much of the AV So2 difference is dependent on Svo2 measurement. The ranges of Svo2 spanned for 35 percent, and the ranges of Sao2 spanned 6 percent in these neonates. The greater intervals for Svo2 measurements contribute to greater sensitivity for the measurements (than Sao2 measurements) in responding to nursing care and changes of O2 demand. Thus, Svo2 measurement is essential for better assessment of oxygenation status in neonates.

The findings of this study on AV differences of So2 were limited with very small number of paired AV blood samples. However, critically ill neonates need accurate assessment of oxygenation status because of HbF, which releases less O2 to the tissues. Decreased differences of AV So2 measurements added further possibilities of lower flow of O2 to the body tissues and demonstrated the greater need to accurately assess the proper oxygenation in the neonates. The findings of this study continued to clarify the accuracy of So2 measurements for neonates. Additional studies are needed to examine So2 levels in neonates to further validate these findings by using larger sample sizes.

Neonatal ventilation strategies and long-term respiratory outcomes

Sandeep Shetty, Anne Greenough
Early Human Development 90 (2014) 735–739
http://dx.doi.org/10.1016/j.earlhumdev.2014.08.020

Long-term respiratory morbidity is common, particularly in those born very prematurely and who have developed bronchopulmonary dysplasia (BPD), but it does occur in those without BPD and in infants born at term. A variety of neonatal strategies have been developed, all with short-term advantages, but meta-analyses of randomized controlled trials (RCTs) have demonstrated that only volume-targeted ventilation and prophylactic high-frequency oscillatory ventilation (HFOV) may reduce BPD. Few RCTs have incorporated long-term follow-up, but one has demonstrated that prophylactic HFOV improves respiratory and functional outcomes at school age, despite not reducing BPD. Results from other neonatal interventions have demonstrated that any impact on BPD may not translate into changes in long-term outcomes. All future neonatal  ventilation RCTs should have long-term outcomes rather than BPD as their primary outcome if they are to impact on clinical practice.

A Model Analysis of Arterial Oxygen Desaturation during Apnea in Preterm Infants

Scott A. Sands, BA Edwards, VJ Kelly, MR Davidson, MH Wilkinson, PJ Berger
PLoS Comput Biol 5(12): e1000588
http://dx.doi.org:/10.1371/journal.pcbi.1000588

Rapid arterial O2 desaturation during apnea in the preterm infant has obvious clinical implications but to date no adequate explanation for why it exists. Understanding the factors influencing the rate of arterial O2 desaturation during apnea (_SSaO2 ) is complicated by the non-linear O2 dissociation curve, falling pulmonary O2 uptake, and by the fact that O2 desaturation is biphasic, exhibiting a rapid phase (stage 1) followed by a slower phase when severe desaturation develops (stage 2). Using a mathematical model incorporating pulmonary uptake dynamics, we found that elevated metabolic O2 consumption accelerates _SSaO2 throughout the entire desaturation process. By contrast, the remaining factors have a restricted temporal influence: low pre-apneic alveolar PO2 causes an early onset of desaturation, but thereafter has little impact; reduced lung volume, hemoglobin content or cardiac output, accelerates _SSaO2 during stage 1, and finally, total blood O2 capacity (blood volume and hemoglobin content) alone determines _SSaO2 during stage 2. Preterm infants with elevated metabolic rate, respiratory depression, low lung volume, impaired cardiac reserve, anemia, or hypovolemia, are at risk for rapid and profound apneic hypoxemia. Our insights provide a basic physiological framework that may guide clinical interpretation and design of interventions for preventing sudden apneic hypoxemia.

A novel approach to study oxidative stress in neonatal respiratory distress syndrome

Reena Negi, D Pande, K Karki, A Kumar, RS Khanna, HD Khanna
BBA Clinical 3 (2015) 65–69
http://dx.doi.org/10.1016/j.bbacli.2014.12.001

Oxidative stress is an imbalance between the systemic manifestation of reactive oxygen species and a biological system’s ability to readily detoxify the reactive intermediates or to repair the resulting damage. It is a physiological event in the fetal-to-neonatal transition, which is actually a great stress to the fetus. These physiological changes and processes greatly increase the production of free radicals, which must be controlled by the antioxidant defense system, the maturation of which follows the course of the gestation. This could lead to several functional alterations with important repercussions for the infants. Adequately mature and healthy infants are able to tolerate this drastic change in the oxygen concentration. A problem occurs when the intrauterine development is incomplete or abnormal. Preterm or intrauterine growth retarded (IUGR) and low birth weight neonates are typically of this kind. An oxidant/antioxidant imbalance in infants is implicated in the pathogenesis of the major complications of prematurity including respiratory distress syndrome (RDS), necrotizing enterocolitis (NEC), chronic lung disease, retinopathy of prematurity and intraventricular hemorrhage (IVH).

Background: Respiratory distress syndrome of the neonate (neonatal RDS) is still an important problem in treatment of preterm infants. It is accompanied by inflammatory processes with free radical generation and oxidative stress. The aim of study was to determine the role of oxidative stress in the development of neonatal RDS. Methods: Markers of oxidative stress and antioxidant activity in umbilical cord blood were studied in infants with neonatal respiratory distress syndrome with reference to healthy newborns. Results: Status of markers of oxidative stress (malondialdehyde, protein carbonyl and 8-hydroxy-2-deoxy guanosine) showed a significant increase with depleted levels of total antioxidant capacity in neonatal RDS when compared to healthy newborns. Conclusion: The study provides convincing evidence of oxidative damage and diminished antioxidant defenses in newborns with RDS. Neonatal RDS is characterized by damage of lipid, protein and DNA, which indicates the augmentation of oxidative stress. General significance: The identification of the potential biomarker of oxidative stress consists of a promising strategy to study the pathophysiology of neonatal RDS.

Neonatal respiratory distress syndrome represents the major lung complications of newborn babies. Preterm neonates suffer from respiratory distress syndrome (RDS) due to immature lungs and require assisted ventilation with high concentrations of oxygen. The pathogenesis of this disorder is based on the rapid formation of the oxygen reactive species, which surpasses the detoxification capacity of antioxidative defense system. The high chemical reactivity of free radical leads to damage to a variety of cellular macro molecules including proteins, lipids and nucleic acid. This results in cell injury and may induce respiratory cell death.

Malondialdehyde (MDA) is one of the final products of polyunsaturated fatty acids peroxidation. The present study showed increased concentration of MDA in neonates with respiratory disorders than that of control in consonance with the reported study.

Anemia, Apnea of Prematurity, and Blood Transfusions

Kelley Zagol, Douglas E. Lake, Brooke Vergales, Marion E. Moorman, et al
J Pediatr 2012;161:417-21
http://dx.doi.org:/10.1016/j.jpeds.2012.02.044

The etiology of apnea of prematurity is multifactorial; however, decreased oxygen carrying capacity may play a role. The respiratory neuronal network in neonates is immature, particularly in those born preterm, as demonstrated by their paradoxical response to hypoxemia. Although adults increase the minute ventilation in response to hypoxemia, newborns have a brief increase in ventilation followed by periodic breathing, respiratory depression, and occasionally cessation of respiratory effort. This phenomenon may be exacerbated by anemia in preterm newborns, where a decreased oxygen carrying capacity may result in decreased oxygen delivery to the central nervous system, a decreased efferent output of the respiratory neuronal network, and an increase in apnea.

Objective Compare the frequency and severity of apneic events in very low birth weight (VLBW) infants before and after blood transfusions using continuous electronic waveform analysis. Study design We continuously collected waveform, heart rate, and oxygen saturation data from patients in all 45 neonatal intensive care unit beds at the University of Virginia for 120 weeks. Central apneas were detected using continuous computer processing of chest impedance, electrocardiographic, and oximetry signals. Apnea was defined as respiratory pauses of >10, >20, and >30 seconds when accompanied by bradycardia (<100 beats per minute) and hypoxemia (<80% oxyhemoglobin saturation as detected by pulse oximetry). Times of packed red blood cell transfusions were determined from bedside charts. Two cohorts were analyzed. In the transfusion cohort, waveforms were analyzed for 3 days before and after the transfusion for all VLBW infants who received a blood transfusion while also breathing spontaneously. Mean apnea rates for the previous 12 hours were quantified and differences for 12 hours before and after transfusion were compared. In the hematocrit cohort, 1453 hematocrit values from all VLBW infants admitted and breathing spontaneously during the time period were retrieved, and the association of hematocrit and apnea in the next 12 hours was tested using logistic regression. Results Sixty-seven infants had 110 blood transfusions during times when complete monitoring data were available. Transfusion was associated with fewer computer-detected apneic events (P < .01). Probability of future apnea occurring within 12 hours increased with decreasing hematocrit values (P < .001). Conclusions Blood transfusions are associated with decreased apnea in VLBW infants, and apneas are less frequent at higher hematocrits.

Bronchopulmonary dysplasia: The earliest and perhaps the longest lasting obstructive lung disease in humans

Silvia Carraro, M Filippone, L Da Dalt, V Ferraro, M Maretti, S Bressan, et al.
Early Human Development 89 (2013) S3–S5
http://dx.doi.org/10.1016/j.earlhumdev.2013.07.015

Bronchopulmonary dysplasia (BPD) is one of the most important sequelae of premature birth and the most common form of chronic lung disease of infancy, an umbrella term for a number of different diseases that evolve as a consequence of a neonatal respiratory disorder. BPD is defined as the need for supplemental oxygen for at least 28 days after birth, and its severity is graded according to the respiratory support required at 36 post-menstrual weeks.

BPD was initially described as a chronic respiratory disease occurring in premature infants exposed to mechanical ventilation and oxygen supplementation. This respiratory disease (later named “old BPD”) occurred in relatively large premature newborn and, from a pathological standpoint, it was characterized by intense airway inflammation, disruption of normal pulmonary structures and lung fibrosis.

Bronchopulmonary dysplasia (BPD) is one of the most important sequelae of premature birth and the most common form of chronic lung disease of infancy. From a clinical standpoint BPD subjects are characterized by recurrent respiratory symptoms, which are very frequent during the first years of life and, although becoming less severe as children grow up, they remain more common than in term-born controls throughout childhood, adolescence and into adulthood. From a functional point of view BPD subjects show a significant airflow limitation that persists during adolescence and adulthood and they may experience an earlier and steeper decline in lung function during adulthood. Interestingly, patients born prematurely but not developing BPD usually fare better, but they too have airflow limitations during childhood and later on, suggesting that also prematurity per se has life-long detrimental effects on pulmonary function. For the time being, little is known about the presence and nature of pathological mechanisms underlying the clinical and functional picture presented by BPD survivors. Nonetheless, recent data suggest the presence of persistent neutrophilic airway inflammation and oxidative stress and it has been suggested that BPD may be sustained in the long term by inflammatory pathogenic mechanisms similar to those underlying COPD. This hypothesis is intriguing but more pathological data are needed.  A better understanding of these pathogenetic mechanisms, in fact, may be able to orient the development of novel targeted therapies or prevention strategies to improve the overall respiratory health of BPD patients.

We have a limited understanding of the presence and nature of pathological mechanisms in the lung of BPD survivors. The possible role of asthma-like inflammation has been investigated because BPD subjects often present with recurrent wheezing and other symptoms resembling asthma during their childhood and adolescence. But BPD subjects have normal or lower than normal exhaled nitric oxide levels and exhaled air temperatures, whereas they are higher than normal in asthmatic patients.

Of all obstructive lung diseases in humans, BPD has the earliest onset and is possibly the longest lasting. Given its frequent association with other conditions related to preterm birth (e.g. growth retardation, pulmonary hypertension, neurodevelopmental delay, hearing defects, and retinopathy of prematurity), it often warrants a multidisciplinary management.

Effects of Sustained Lung Inflation, a lung recruitment maneuver in primary acute respiratory distress syndrome, in respiratory and cerebral outcomes in preterm infants

Chiara Grasso, Pietro Sciacca, Valentina Giacchi, Caterina Carpinato, et al.
Early Human Development 91 (2015) 71–75
http://dx.doi.org/10.1016/j.earlhumdev.2014.12.002

Background: Sustained Lung Inflation (SLI) is a maneuver of lung recruitment in preterm newborns at birth that can facilitate the achieving of larger inflation volumes, leading to the clearance of lung fluid and formation of functional residual capacity (FRC). Aim: To investigate if Sustained Lung Inflation (SLI) reduces the need of invasive procedures and iatrogenic risks. Study design: 78 newborns (gestational age ≤ 34 weeks, weighing ≤ 2000 g) who didn’t breathe adequately at birth and needed to receive SLI in addition to other resuscitation maneuvers (2010 guidelines). Subjects: 78 preterm infants born one after the other in our department of Neonatology of Catania University from 2010 to 2012. Outcome measures: The need of intubation and surfactant, the ventilation required, radiological signs, the incidence of intraventricular hemorrhage (IVH), periventricular leukomalacia, retinopathy in prematurity from III to IV plus grades, bronchopulmonary dysplasia, patent ductus arteriosus, pneumothorax and necrotizing enterocolitis. Results: In the SLI group infants needed less intubation in the delivery room (6% vs 21%; p b 0.01), less invasive mechanical ventilation (14% vs 55%; p ≤ 0.001) and shorter duration of ventilation (9.1 days vs 13.8 days; p ≤ 0.001). There wasn’t any difference for nasal continuous positive airway pressure (82% vs 77%; p = 0.43); but there was less surfactant administration (54% vs 85%; p ≤ 0.001) and more infants received INSURE (40% vs 29%; p=0.17). We didn’t found any differences in the outcomes, except for more mild intraventricular hemorrhage in the SLI group (23% vs 14%; p = 0.15; OR= 1.83). Conclusion: SLI is easier to perform even with a single operator, it reduces the necessity of more complicated maneuvers and surfactant without statistically evident adverse effects.

Long-term respiratory consequences of premature birth at less than 32 weeks of gestation

Anne Greenough
Early Human Development 89 (2013) S25–S27
http://dx.doi.org/10.1016/j.earlhumdev.2013.07.004

Chronic respiratory morbidity is a common adverse outcome of very premature birth, particularly in infants who had developed bronchopulmonary dysplasia (BPD). Prematurely born infants who had BPD may require supplementary oxygen at home for many months and affected infants have increased healthcare utilization until school age. Chest radiograph abnormalities are common; computed tomography of the chest gives predictive information in children with ongoing respiratory problems. Readmission to hospital is common, particularly for those who have BPD and suffer respiratory syncytial virus lower respiratory infections (RSV LRTIs). Recurrent respiratory symptoms requiring treatment are common and are associated with evidence of airways obstruction and gas trapping. Pulmonary function improves with increasing age, but children with BPD may have ongoing airflow limitation. Lung function abnormalities may be more severe in those who had RSV LRTIs, although this may partly be explained by worse premorbid lung function. Worryingly, lung function may deteriorate during the first year. Longitudinal studies are required to determine if there is catch up growth.

Long-term pulmonary outcomes of patients with bronchopulmonary dysplasia

Anita Bhandari and Sharon McGrath-Morrow
Seminars in Perinatology 37 (2013)132–137
http://dx.doi.org/10.1053/j.semperi.2013.01.010

Bronchopulmonary dysplasia (BPD) is the commonest cause of chronic lung disease in infancy. The incidence of BPD has remained unchanged despite many advances in neonatal care. BPD starts in the neonatal period but its effects can persist long term. Premature infants with BPD have a greater incidence of hospitalization, and continue to have a greater respiratory morbidity and need for respiratory medications, compared to those without BPD. Lung function abnormalities, especially small airway abnormalities, often persist. Even in the absence of clinical symptoms, BPD survivors have persistent radiological abnormalities and presence of emphysema has been reported on chest computed tomography scans. Concern regarding their exercise tolerance remains. Long-term effects of BPD are still unknown, but given reports of a more rapid decline in lung function and their susceptibility to develop chronic obstructive pulmonary disease phenotype with aging, it is imperative that lung function of survivors of BPD be closely monitored.

Neonatal ventilation strategies and long-term respiratory outcomes

Sandeep Shetty, Anne Greenough
Early Human Development 90 (2014) 735–739
http://dx.doi.org/10.1016/j.earlhumdev.2014.08.020

Long-term respiratory morbidity is common, particularly in those born very prematurely and who have developed bronchopulmonary dysplasia (BPD), but it does occur in those without BPD and in infants born at term. A variety of neonatal strategies have been developed, all with short-term advantages, but meta-analyses of randomized controlled trials (RCTs) have demonstrated that only volume-targeted ventilation and prophylactic high-frequency oscillatory ventilation (HFOV) may reduce BPD. Few RCTs have incorporated long-term follow-up, but one has demonstrated that prophylactic HFOV improves respiratory and functional outcomes at school age, despite not reducing BPD. Results from other neonatal interventions have demonstrated that any impact on BPD may not translate into changes in long-term outcomes. All future neonatal ventilation RCTs should have long-term outcomes rather than BPD as their primary outcome if they are to impact on clinical practice.

Prediction of neonatal respiratory distress syndrome in term pregnancies by assessment of fetal lung volume and pulmonary artery resistance index

Mohamed Laban, GM Mansour, MSE Elsafty, AS Hassanin, SS EzzElarab
International Journal of Gynecology and Obstetrics 128 (2015) 246–250
http://dx.doi.org/10.1016/j.ijgo.2014.09.018

Objective: To develop reference cutoff values for mean fetal lung volume (FLV) and pulmonary artery resistance index (PA-RI) for prediction of neonatal respiratory distress syndrome (RDS) in low-risk term pregnancies. Methods: As part of a cross-sectional study, women aged 20–35 years were enrolled and admitted to a tertiary hospital in Cairo, Egypt, for elective repeat cesarean at 37–40 weeks of pregnancy between January 1, 2012, and July 31, 2013. FLV was calculated by virtual organ computer-aided analysis, and PA-RI was measured by Doppler ultrasonography before delivery. Results: A total of 80 women were enrolled. Neonatal RDS developed in 11 (13.8%) of the 80 newborns. Compared with neonates with RDS, healthy neonates had significantly higher FLVs (P b 0.001) and lower PA-RIs (P b 0.001). Neonatal RDS is less likely with FLV of at least 32 cm3 or PA-RI less than or equal to 0.74. Combining these two measures improved the accuracy of prediction. Conclusion: The use of either FLV or PA-RI predicted neonatal RDS. The predictive value increased when these two measures were combined

Pulmonary surfactant - a front line of lung host defense, 2003 JCI0318650.f2

Pulmonary surfactant – a front line of lung host defense, 2003 JCI0318650.f2

Pulmonary hypertension in bronchopulmonary dysplasia

Sara K.Berkelhamer, Karen K.Mestan, and Robin H. Steinhorn
Seminars In  Perinatology 37 (2013)124–131
http://dx.doi.org/10.1053/j.semperi.2013.01.009

Pulmonary hypertension (PH) is a common complication of neonatal respiratory diseases, including bronchopulmonary dysplasia (BPD), and recent studies have increased aware- ness that PH worsens the clinical course, morbidity and mortality of BPD. Recent evidence indicates that up to 18% of all extremely low-birth-weight infants will develop some degree of PH during their hospitalization, and the incidence rises to 25–40% of the infants with established BPD. Risk factors are not yet well understood, but new evidence shows that fetal growth restriction is a significant predictor of PH. Echocardiography remains the primary method for evaluation of BPD-associated PH, and the development of standardized screening timelines and techniques for identification of infants with BPD-associated PH remains an important ongoing topic of investigation. The use of pulmonary vasodilator medications, such as nitric oxide, sildenafil, and others, in the BPD population is steadily growing, but additional studies are needed regarding their long-term safety and efficacy.
An update on pharmacologic approaches to bronchopulmonary dysplasia

Sailaja Ghanta, Kristen Tropea Leeman, and Helen Christou
Seminars In Perinatology 37 (2013)115–123
http://dx.doi.org/10.1053/j.semperi.2013.01.008

Bronchopulmonary dysplasia (BPD) is the most prevalent long-term morbidity in surviving extremely preterm infants and is linked to increased risk of reactive airways disease, pulmonary hypertension, post-neonatal mortality, and adverse neurodevelopmental outcomes. BPD affects approximately 20% of premature newborns, and up to 60% of premature infants born before completing 26 weeks of gestation. It is characterized by the need for assisted ventilation and/or supplemental oxygen at 36 weeks postmenstrual age. Approaches to prevention and treatment of BPD have evolved with improved understanding of its pathogenesis. This review will focus on recent advancements and detail current research in pharmacotherapy for BPD. The evidence for both current and potential future experimental therapies will be reviewed in detail. As our understanding of the complex and multifactorial pathophysiology of BPD changes, research into these current and future approaches must continue to evolve.

Methylxanthines
Diuretics and bronchodilators
Corticosteroids
Macrolide antibiotics
Recombinant human Clara cell 10-kilodalton protein(rhCC10)
Vitamin A
Surfactant
Leukotriene receptor antagonist
Pulmonary vasodilators

Skeletal and Muscle

Skeletal Stem Cells in Space and Time

Moustapha Kassem and Paolo Bianco
Cell  Jan 15, 2015; 160: 17-19
http://dx.doi.org/10.1016/j.cell.2014.12.034

The nature, biological characteristics, and contribution to organ physiology of skeletal stem cells are not completely determined. Chan et al. and Worthley et al. demonstrate that a stem cell for skeletal tissues, and a system of more restricted, downstream progenitors, can be identified in mice and demonstrate its role in skeletal tissue maintenance and regeneration.

The groundbreaking concept that bone, cartilage, marrow adipocytes, and hematopoiesis-supporting stroma could originate from a common progenitor and putative stem cell was surprising at the time when it was formulated (Owen and Friedenstein, 1988). The putative stem cell, nonhematopoietic in nature, would be found in the postnatal bone marrow stroma, generate tissues previously thought of as foreign to each other, and support the turnover of tissues and organs that self-renew at a much slower rate compared to other tissues associated with stem cells (blood, epithelia). This concept also connected bone and bone marrow as parts of a single-organ system, implying their functional interplay. For many years, the evidence underpinning the concept has been incomplete.

While multipotency of stromal progenitors has been demonstrated by in vivo transplantation experiments, self-renewal, the defining property of a stem cell, has not been easily demonstrated until recently in humans (Sacchetti et al., 2007) and mice (Mendez-Ferrer et al., 2010). Meanwhile, a confusing and plethoric terminology has been introduced into the literature, which diverted and confounded the search for a skeletal stem cell and its physiological significance (Bianco et al., 2013).

Two studies in this issue of Cell (Chan et al., 2015; Worthley et al., 2015), using a combination of rigorous single-cell analyses and lineage tracing technologies, mark significant steps toward rectifying the course of skeletal stem cell discovery by making several important points, within and beyond skeletal physiology.

First, a stem cell for skeletal tissues, and a system of more restricted, downstream progenitors can in fact be identified and linked to defined phenotype(s) in the mouse. The system is framed conceptually, and approached experimentally, similar to the hematopoietic system.

Second, based on its assayable functions and potential, the stem cell at the top of the hierarchy is defined as a skeletal stem cell (SSC). As noted earlier (Sacchetti et al., 2007) (Bianco et al., 2013), this term clarifies, well beyond semantics, that the range of tissues that the self-renewing stromal progenitor (originally referred to as an ‘‘osteogenic’’ or ‘‘stromal’’ stem cell) (Owen and Friedenstein, 1988) can actually generate in vivo, overlaps with the range of tissues that make up the skeleton.

Third, these cells are spatially restricted, local residents of the bone/bone marrow organ. The systemic circulation is not a sizable contributor to their recruitment to locally deployed functions.

Fourth, a native skeletogenic potential is inherent to the system of progenitor/ stem cells found in the skeleton, and internally regulated by bone morphogenetic protein (BMP) signaling. This is reflected in the expression of regulators and antagonists of BMP signaling within the system, highlighting potential feedback mechanisms modulating expansion or quiescence of specific cell compartments.

Fifth, in cells isolated from other tissues, an assayable skeletogenic potential is not inherent: it can only be induced de novo by BMP reprogramming. These two studies (Chan et al., 2015, Worthley et al., 2015) corroborate the classical concept of ‘‘determined’’ and ‘‘inducible’’ skeletal progenitors (Owen and Friedenstein, 1988): the former residing in the skeleton, the latter found in nonskeletal tissues; the former capable of generating skeletal tissues, in vivo and spontaneously, the latter requiring reprogramming signals in order to acquire a skeletogenic capacity; the former operating in physiological bone formation, the latter in unwanted, ectopic bone formation in diseases such as fibrodysplasia ossificans progressiva.

To optimize our ability to obtain specific skeletal tissues for medical application, the study by Chan et al. offers a glimpse of another facet of the biology of SSC lineages and progenitors. Chan et al. show that a homogeneous cell population inherently committed to chondrogenesis can alter its output to generate bone if cotransplanted with multipotent progenitors. Conversely, osteogenic cells can be shifted to a chondrogenic fate by blockade of vascular endothelial growth factor receptor, consistent with the avascular and hypoxic milieu of cartilage. This has two important implications:

  • commitment is flexible in the system;
  • the choir is as important as the soloist and can modulate the solo tune.

Reversibility and population behavior thus emerge as two features that may be characteristic, albeit not unique, of the stromal system, resonating with conceptually comparable evidence in the human system.

The two studies by Chan et al. and Worthely et al. emphasize the relevance not only of their new data, but also of a proper concept of a skeletal stem cell per se, for proper clinical use. Confusion arising from improper conceptualization of skeletal stem cells has markedly limited clinical development of skeletal stem cell biology.

Gremlin 1 Identifies a Skeletal Stem Cell with Bone, Cartilage, and Reticular Stromal Potential

Daniel L. Worthley, Michael Churchill, Jocelyn T. Compton, Yagnesh Tailor, et al.
Cell, Jan 15, 2015; 160: 269–284
http://dx.doi.org/10.1016/j.cell.2014.11.042

The stem cells that maintain and repair the postnatal skeleton remain undefined. One model suggests that perisinusoidal mesenchymal stem cells (MSCs) give rise to osteoblasts, chondrocytes, marrow stromal cells, and adipocytes, although the existence of these cells has not been proven through fate-mapping experiments. We demonstrate here that expression of the bone morphogenetic protein (BMP) antagonist gremlin 1 defines a population of osteochondroreticular (OCR) stem cells in the bone marrow. OCR stem cells self-renew and generate osteoblasts, chondrocytes, and reticular marrow stromal cells, but not adipocytes. OCR stem cells are concentrated within the metaphysis of long bones not in the perisinusoidal space and are needed for bone development, bone remodeling, and fracture repair. Grem1 expression also identifies intestinal reticular stem cells (iRSCs) that are cells of origin for the periepithelial intestinal mesenchymal sheath. Grem1 expression identifies distinct connective tissue stem cells in both the bone (OCR stem cells) and the intestine (iRSCs).

Identification and Specification of the Mouse Skeletal Stem Cell

Charles K.F. Chan, Eun Young Seo, James Y. Chen, David Lo, A McArdle, et al.
Cell, Jan 15, 2015; 160: 285–298
http://dx.doi.org/10.1016/j.cell.2014.12.002

How are skeletal tissues derived from skeletal stem cells? Here, we map bone, cartilage, and stromal development from a population of highly pure, postnatal skeletal stem cells (mouse skeletal stem cells, mSSCs) to their downstream progenitors of bone, cartilage, and stromal tissue. We then investigated the transcriptome of the stem/progenitor cells for unique gene-expression patterns that would indicate potential regulators of mSSC lineage commitment. We demonstrate that mSSC niche factors can be potent inducers of osteogenesis, and several specific combinations of recombinant mSSC niche factors can activate mSSC genetic programs in situ, even in nonskeletal tissues, resulting in de novo formation of cartilage or bone and bone marrow stroma. Inducing mSSC formation with soluble factors and subsequently regulating the mSSC niche to specify its differentiation toward bone, cartilage, or stromal cells could represent a paradigm shift in the therapeutic regeneration of skeletal tissues.

Bone mesenchymal development

Bone mesenchymal development

Bone mesenchymal development

The bone-remodeling cycle

The bone-remodeling cycle

Nuclear receptor modulation – Role of coregulators in selective estrogen receptor modulator (SERM) actions

Qin Feng, Bert W. O’Malley
Steroids 90 (2014) 39–43
http://dx.doi.org/10.1016/j.steroids.2014.06.008

Selective estrogen receptor modulators (SERMs) are a class of small-molecule chemical compounds that bind to estrogen receptor (ER) ligand binding domain (LBD) with high affinity and selectively modulate ER transcriptional activity in a cell- and tissue-dependent manner. The prototype of SERMs is tamoxifen, which has agonist activity in bone, but has antagonist activity in breast. Tamoxifen can reduce the risk of breast cancer and, at same time, prevent osteoporosis in postmenopausal women. Tamoxifen is widely prescribed for treatment and prevention of breast cancer. Mechanistically the activity of SERMs is determined by the selective recruitment of coactivators and corepressors in different cell types and tissues. Therefore, understanding the coregulator function is the key to understanding the tissue selective activity of SERMs.

Hematopoietic

Hematopoietic Stem Cell Arrival Triggers Dynamic Remodeling of the Perivascular Niche

Owen J. Tamplin, Ellen M. Durand, Logan A. Carr, Sarah J. Childs, et al.
Cell, Jan 15, 2015; 160: 241–252
http://dx.doi.org/10.1016/j.cell.2014.12.032

Hematopoietic stem and progenitor cells (HSPCs) can reconstitute and sustain the entire blood system. We generated a highly specific transgenic reporter of HSPCs in zebrafish. This allowed us to perform high resolution live imaging on endogenous HSPCs not currently possible in mammalian bone marrow. Using this system, we have uncovered distinct interactions between single HSPCs and their niche. When an HSPC arrives in the perivascular niche, a group of endothelial cells remodel to form a surrounding pocket. This structure appears conserved in mouse fetal liver. Correlative light and electron microscopy revealed that endothelial cells surround a single HSPC attached to a single mesenchymal stromal cell. Live imaging showed that mesenchymal stromal cells anchor HSPCs and orient their divisions. A chemical genetic screen found that the compound lycorine promotes HSPC-niche interactions during development and ultimately expands the stem cell pool into adulthood. Our studies provide evidence for dynamic niche interactions upon stem cell colonization.

Neonatal anemia

Sanjay Aher, Kedar Malwatkar, Sandeep Kadam
Seminars in Fetal & Neonatal Medicine (2008) 13, 239e247
http://dx.doi.org:/10.1016/j.siny.2008.02.009

Neonatal anemia and the need for red blood cell (RBC) transfusions are very common in neonatal intensive care units. Neonatal anemia can be due to blood loss, decreased RBC production, or increased destruction of erythrocytes. Physiologic anemia of the newborn and anemia of prematurity are the two most common causes of anemia in neonates. Phlebotomy losses result in much of the anemia seen in extremely low birthweight infants (ELBW). Accepting a lower threshold level for transfusion in ELBW infants can prevent these infants being exposed to multiple donors.

Management of anemia in the newborn

Naomi L.C. Luban
Early Human Development (2008) 84, 493–498
http://dx.doi.org:/10.1016/j.earlhumdev.2008.06.007

Red blood cell (RBC) transfusions are administered to neonates and premature infants using poorly defined indications that may result in unintentional adverse consequences. Blood products are often manipulated to limit potential adverse events, and meet the unique needs of neonates with specific diagnoses. Selection of RBCs for small volume (5–20 mL/kg) transfusions and for massive transfusion, defined as extracorporeal bypass and exchange transfusions, are of particular concern to neonatologists. Mechanisms and therapeutic treatments to avoid transfusion are another area of significant investigation. RBCs collected in anticoagulant additive solutions and administered in small aliquots to neonates over the shelf life of the product can decrease donor exposure and has supplanted the use of fresh RBCs where each transfusion resulted in a donor exposure. The safety of this practice has been documented and procedures established to aid transfusion services in ensuring that these products are available. Less well established are the indications for transfusion in this population; hemoglobin or hematocrit alone are insufficient indications unless clinical criteria (e.g. oxygen desaturation, apnea and bradycardia, poor weight gain) also augment the justification to transfuse. Comorbidities increase oxygen consumption demands in these infants and include bronchopulmonary dysplasia, rapid growth and cardiac dysfunction. Noninvasive methods or assays have been developed to measure tissue oxygenation; however, a true measure of peripheral oxygen offloading is needed to improve transfusion practice and determine the value of recombinant products that stimulate erythropoiesis. The development of such noninvasive methods is especially important since randomized, controlled clinical trials to support specific practices are often lacking, due at least in part, to the difficulty of performing such studies in tiny infants.
The Effect of Blood Transfusion on the Hemoglobin Oxygen Dissociation Curve of Very Early Preterm Infants During the First Week of Life

Virginie De HaUeux, Anita Truttmann, Carmen Gagnon, and Harry Bard
Seminars in Perinatology, 2002; 26(6): 411-415
http://dx.doi.org:/10.1053/sper.2002.37313

This study was conducted during the first week of life to determine the changes in Ps0 (PO2 required to achieve a saturation of 50% at pH 7.4 and 37~ and the proportions of fetal hemoglobin (I-IbF) and adult hemoglobin (HbA) prior to and after transfusion in very early preterm infants. Eleven infants with a gestational age <–27 weeks have been included in study. The hemoglobin dissociation curve and the Ps0 was determined by Hemox-analyser. Liquid chromatography was also performed to determine the proportions of HbF and HbA. The mean gestational age of the 11 infants was 25.1 weeks (-+1 weeks) and their mean birth weight was 736 g (-+125 g). They received 26.9 mL/kg of packed red cells. The mean Ps0 prior and after transfusion was 18.5 +- 0.8 and 21.0 + 1 mm Hg (P = .0003) while the mean percentage of HbF was 92.9 -+ 1.1 and 42.6 -+ 5.7%, respectively. The data of this study show a decrease of hemoglobin oxygen affinity as a result of blood transfusion in very early preterm infants prone to O 2 toxicity. The shift in HbO 2 curve after transfusion should be taken into consideration when oxygen therapy is being regulated for these infants.

Effect of neonatal hemoglobin concentration on long-term outcome of infants affected by fetomaternal hemorrhage

Mizuho Kadooka, H Katob, A Kato, S Ibara, H Minakami, Yuko Maruyama
Early Human Development 90 (2014) 431–434
http://dx.doi.org/10.1016/j.earlhumdev.2014.05.010

Background: Fetomaternal hemorrhage (FMH) can cause severe morbidity. However, perinatal risk factors for long-term poor outcome due to FMH have not been extensively studied.                                                                                 Aims: To determine which FMH infants are likely to have neurological sequelae.
Study design: A single-center retrospective observational study. Perinatal factors, including demographic characteristics, Kleihauer–Betke test, blood gas analysis, and neonatal blood hemoglobin concentration ([Hb]), were analyzed in association with long-term outcomes.
Subjects: All 18 neonates referred to a Neonatal Intensive Care Unit of Kagoshima City Hospital and diagnosed with FMH during a 15-year study period. All had a neonatal [Hb] b7.5 g/dL and 15 of 17 neonates tested had Kleihauer–Betke test result N4.0%.
Outcome measures: Poor long-term outcome was defined as any of the following determined at 12 month old or more: cerebral palsy, mental retardation, attention deficit/hyperactivity disorder, and epilepsy.
Results: Nine of the 18 neonates exhibited poor outcomes. Among demographic characteristics and blood variables compared between two groups with poor and favorable outcomes, significant differences were observed in [Hb] (3.6 ± 1.4 vs. 5.4 ± 1.1 g/dL, P = 0.01), pH (7.09 ± 0.11 vs. 7.25 ± 0.13, P = 0.02) and base deficits (17.5 ± 5.4 vs. 10.4 ± 6.0 mmol/L, P = 0.02) in neonatal blood, and a number of infants with [Hb] ≤ 4.5 g/dL (78%[7/9] vs. 22%[2/9], P= 0.03), respectively. The base deficit in neonatal arterial blood increased significantly with decreasing neonatal [Hb].
Conclusions: Severe anemia causing severe base deficit is associated with neurological sequelae in FMH infants

Clinical and hematological presentation among Indian patients with common hemoglobin variants

Khushnooma Italia, Dipti Upadhye, Pooja Dabke, Harshada Kangane, et al.
Clinica Chimica Acta 431 (2014) 46–51
http://dx.doi.org/10.1016/j.cca.2014.01.028

Background: Co-inheritance of structural hemoglobin variants like HbS, HbD Punjab and HbE can lead to a variable clinical presentation and only few cases have been described so far in the Indian population.
Methods: We present the varied clinical and hematological presentation of 22 cases (HbSD Punjab disease-15, HbSE disease-4, HbD Punjab E disease-3) referred to us for diagnosis.
Results: Two of the 15 HbSDPunjab disease patients had moderate crisis, one presented with mild hemolytic anemia; however, the other 12 patients had a severe clinical presentation with frequent blood transfusion requirements, vaso occlusive crisis, avascular necrosis of the femur and febrile illness. The 4 HbSE disease patients had a mild to moderate presentation. Two of the 3 HbD Punjab E patients were asymptomatic with one patient’s sibling having a mild presentation. The hemoglobin levels of the HbSD Punjab disease patients ranged from 2.3 to 8.5 g/dl and MCV from 76.3 to 111.6 fl. The hemoglobin levels of the HbD Punjab E and HbSE patients ranged from 10.8 to 11.9 and 9.8 to 10.0 g/dl whereas MCV ranged from 67.1 to 78.2 and 74.5 to 76.0 fl respectively.
Conclusions: HbSD Punjab disease patients should be identified during newborn screening programs and managed in a way similar to sickle cell disease. Couple at risk of having HbSD Punjab disease children may be given the option of prenatal diagnosis in subsequent pregnancies.

Sickle cell anemia is the most common hemoglobinopathy seen across the world. It is caused by a point mutation in the 6th codon of the beta (β) globin gene leading to the substitution of the amino acid glutamic acid to valine. The sickle gene is frequently seen in Africa, some Mediterranean countries, India, Middle East—Saudi Arabia and North America. In India the prevalence of hemoglobin S (HbS) carriers varies from 2 to 40% among different population groups and HbS is mainly seen among the scheduled tribe, scheduled caste and other backward class populations in the western, central and parts of eastern and southern India. Sickle cell anemia has a variable clinical presentation in India with the most severe clinical presentation seen in central India whereas patients in the western region show a mild to moderate clinical presentation.

Hemoglobin D Punjab (HbD Punjab) (also known as HbD Los-Angeles, HbD Portugal, HbD North Carolina, D Oak Ridge and D Chicago) is another hemoglobin variant due to a point mutation in codon 121 of the β globin gene resulting in the substitution of the amino acid glutamic acid to glycine. It is a widely distributed hemoglobin with a relatively low prevalence of 0.86% in the Indo-Pak subcontinent, 1–3% in north-western India, 1–3% in the Black population in the Caribbean and North America and has also been reported among the English. It accounts for 55.6% of all the Hb variants seen in the Xenjiang province of China.

Hemoglobin E (HbE) is the most common abnormal hemoglobin in Southeast Asia. In India, the frequency ranges from 4% to 51% in the north eastern region and 3% to 4% in West Bengal in the east. The HbE mutation (β26 GAG→AAG) creates an alternative splice site and the βE chain is insufficiently synthesized, hence the phenotype of this disorder is that of a mild form of β thalassemia.

Though these 3 structural variants are prevalent in different regions of India, their interaction is increasingly seen in all states of the country due to migration of people to different regions for a better livelihood. There are very few reports on interaction of these commonly seen Hb variants and the phenotypic–genotypic presentation of these cases is important for genetic counseling and management.

HbF of patients with HbSD Punjab disease with variable clinical severity. The HbF values of 4 patients are not included as they were post blood transfusion

The genotypes of the patients were confirmed by restriction enzyme digestion and ARMS (Fig). Patients 1 to 15 were characterized as compound heterozygous for HbS and HbD Punjab whereas patients 16 to 19 were characterized as compound heterozygous for HbS and HbE. Patient nos. 20 to 22 were characterized as compound heterozygous for HbE and HbD Punjab.

Molecular characterization of HbS and HbDPunjab by restriction enzyme digestion and of HbE by ARMS.

Molecular characterization of HbS and HbDPunjab by restriction enzyme digestion and of HbE by ARMS.

Molecular characterization of HbS and HbDPunjab by restriction enzyme digestion and of HbE by ARMS.

The 3 common β globin gene variants of hemoglobin, HbS, HbE and HbD Punjab are commonly seen in India, with HbS having a high prevalence in the central belt and some parts of western, eastern and southern India, HbE in the eastern and north eastern region whereas HbD is mostly seen in the north western part of India. These hemoglobin variants have been reported in different population groups. However, with migration and intermixing of the different populations from different geographic regions, occasional cases of HbSD Punjab and HbSE are being reported. There are several HbD variants like HbD Punjab, HbD Iran, HbD Ibadan. However, of these only HbD Punjab interacts with HbS to form a clinically significant condition as the glutamine residue facilitates polymerization of HbS. HbD Iran and HbD Ibadan are non-interacting and produce benign conditions like the sickle cell trait. The first case of HbSD Punjab disease was a brother and sister considered to have atypical sickle cell disease in 1934. This family was further reinvestigated and reported as the first case of HbD Los Angeles which has the same mutation as the HbD Punjab. Serjeant et al. reported HbD Punjab in an English parent in 6 out of 11 HbSD-Punjab disease cases. This has been suggested to be due to the stationing of nearly 50,000 British troops on the Indian continent for a period of 200 y and the introduction into Britain of their Anglo-Indian children.

HbSD Punjab disease shows a similar pattern to HbS homozygous on alkaline hemoglobin electrophoresis but can be differentiated on acid agar gel electrophoresis and on HPLC. In HbSD Punjab disease cases, the peripheral blood films show anisocytosis, poikilocytosis, target cells and irreversibly sickled cells. Values of HbF and HbA2 are similar to those in sickle homozygous cases. HbSD Punjab disease is characterized by a moderately severe hemolytic anemia.

Twenty-one cases of HbSDPunjab were reported by Serjeant of which 16 were reported by different workers among patients originating from Caucasian, Spanish, Australian, Irish, English, Portuguese, Black, American, Venezuelan, Caribbean, Mexican, Turkish and Jamaican backgrounds. Yavarian et al. 2009 reported a multi centric origin of HbD Punjab which in combination with HbS results in sickle cell disease. Patel et al. 2010 have also reported 12 cases of HbSD Punjab from the Orissa state of eastern India. Majority of these cases were symptomatic, presenting with chronic hemolytic anemia and frequent painful crises.

HbF levels >20% were seen in 4 out of our 11 clinically severe patients of HbSD-Punjab disease with the mean HbF levels of 16.8% in 8 clinically severe patients, while 3 clinically severe patients were post transfused. However, the 3 patients with a mild to moderate clinical presentation showed a mean HbF level of 8.6%. This is in contrast to the relatively milder clinical presentation associated with high HbF seen in patients with sickle cell anemia. This was also reported by Adekile et al. 2010 in 5 cases of HbS-DLos Angeles where high HbF did not ameliorate the severe clinical presentation seen in these patients.

These 15 cases of HbSDPunjab disease give us an overall idea of the severe clinical presentation of the disease in different regions of India. However the HbDPunjabE cases were milder or asymptomatic and the HbSE cases were moderately symptomatic. Since most of the cases of HbSDPunjab disease were clinically severe, it is important to pick up these cases during newborn screening and enroll them into a comprehensive care program with the other sickle cell disease patients with introduction of therapeutic interventions such as penicillin prophylaxis if required and pneumococcal immunization. In fact, 2 of our cases (No. 6 and 7) were identified during newborn screening for sickle cell disorders. The parents can be given information on home care and educated to detect symptoms that may lead to serious medical emergencies. The parents of these patients as well as the couples who are at risk of having a child with HbSDPunjab disease could also be counseled about the option of prenatal diagnosis in subsequent pregnancies. It is thus important to document the clinical and hematological presentation of compound heterozygotes with these common β globin chain variants.

Common Hematologic Problems in the Newborn Nursery

Jon F. Watchko
Pediatr Clin N Am – (2015) xxx-xxx
http://dx.doi.org/10.1016/j.pcl.2014.11.011

Common RBC disorders include hemolytic disease of the newborn, anemia, and polycythemia. Another clinically relevant hematologic issue in neonates to be covered herein is thrombocytopenia. Disorders of white blood cells will not be reviewed.

KEY POINTS

(1)               Early clinical jaundice or rapidly developing hyperbilirubinemia are often signs of hemolysis, the differential diagnosis of which commonly includes immune-mediated disorders, red-cell enzyme deficiencies, and red-cell membrane defects.

(2)             Knowledge of the maternal blood type and antibody screen is critical in identifying non-ABO alloantibodies in the maternal serum that may pose a risk for severe hemolytic disease in the newborn.

(3)             Moderate to severe thrombocytopenia in an otherwise well-appearing newborn strongly suggests immune-mediated (alloimmune or autoimmune) thrombocytopenia.

Hemolytic conditions in the neonate

1. Immune-mediated (positive direct Coombs test)  a. Rhesus blood group: Anti-D, -c, -C, -e, -E, CW, and several others

  b. Non-Rhesus blood groups: Kell, Duffy, Kidd, Xg, Lewis, MNS, and others

  c. ABO blood group: Anti-A, -B

2. Red blood cell (RBC) enzyme defects

  a. Glucose-6-phosphate dehydrogenase (G6PD) deficiency

  b. Pyruvate kinase deficiency

  c. Others

3. RBC membrane defects

  a. Hereditary spherocytosis

  b. Elliptocytosis

  c. Stomatocytosis

  d. Pyknocytosis

  e. Others

4. Hemoglobinopathies

  a. alpha-thalassemia

  b. gamma-thalassemia

Standard maternal antibody screeningAlloantibody                                 Blood Group

D, C, c, E, e, f, CW, V                     Rhesus

K, k, Kpa, Jsa                                  Kell

Fya, Fyb                                          Duffy

Jka, Jkb                                           Kidd

Xga                                                  Xg

Lea, Leb                                          Lewis

S, s, M, N                                        MNS

P1                                                    P

Lub                                                  Lutheran

Non-ABO alloantibodies reported to cause moderate to severe hemolytic disease of the newbornWithin Rh system: Anti-D, -c, -C, -Cw, -Cx, -e, -E, -Ew, -ce, -Ces, -Rh29, -Rh32, -Rh42, -f, -G, -Goa, -Bea, -Evans, -Rh17, -Hro, -Hr, -Tar, -Sec, -JAL, -STEM

Outside Rh system:  Anti-LW, -K, -k, -Kpa, -Kpb, -Jka, -Jsa, -Jsb, -Ku, -K11, -K22, -Fya, -M, -N, -S, -s, -U, -PP1 pk, -Dib, -Far, -MUT, -En3, -Hut, -Hil, -Vel, -MAM, -JONES, -HJK, -REIT

 

Red Blood Cell Enzymopathies

G6PD9 and pyruvate kinase (PK) deficiency are the 2 most common red-cell enzyme disorders associated with marked neonatal hyperbilirubinemia. Of these, G6PD deficiency is the more frequently encountered and it remains an important cause of kernicterus worldwide, including the United States, Canada, and the United Kingdom, the prevalence in Western countries a reflection in part of immigration patterns and intermarriage. The risk of kernicterus in G6PD deficiency also relates to the potential for unexpected rapidly developing extreme hyperbilirubinemia in this disorder associated with acute severe hemolysis.

Red Blood Cell Membrane Defects

Establishing a diagnosis of RBC membrane defects is classically based on the development of Coombs-negative hyperbilirubinemia, a positive family history, and abnormal RBC smear, albeit it is often difficult because newborns normally exhibit a marked variation in red-cell membrane size and shape. Spherocytes, however, are not often seen on RBC smears of hematologically normal newborns and this morphologic abnormality, when prominent, may yield a diagnosis of hereditary spherocytosis (HS) in the immediate neonatal period. Given that approximately 75% of families affected with hereditary spherocytosis manifest an autosomal dominant phenotype, a positive family history can often be elicited and provide further support for this diagnosis. More recently, Christensen and Henry highlighted the use of an elevated mean corpuscular hemoglobin concentration (MCHC) (>36.0 g/dL) and/or elevated ratio of MCHC to mean corpuscular volume, the latter they term the “neonatal HS index” (>0.36, likely >0.40) as screening tools for HS. An index of greater than 0.36 had 97% sensitivity, greater than 99% specificity, and greater than 99% negative predictive value for identifying HS in neonates. Christensen and colleagues also provided a concise update of morphologic RBC features that may be helpful in diagnosing this and other underlying hemolytic conditions in newborns.

The diagnosis of HS can be confirmed using the incubated osmotic fragility test when coupled with fetal red-cell controls or eosin-5-maleimide flow cytometry. One must rule out symptomatic ABO hemolytic disease by performing a direct Coombs test, as infants so affected also may manifest prominent micro-spherocytosis. Moreover, HS and symptomatic ABO hemolytic disease can occur in the same infant and result in severe hyperbilirubinemia and anemia.  Of other red-cell membrane defects, only hereditary elliptocytosis,  stomato-cytosis, and infantile pyknocytosis have been reported to exhibit significant hemolysis in the newborn period. Hereditary elliptocytosis and stomatocytosis are both rare. Infantile pyknocytosis, a transient red-cell membrane abnormality manifesting itself during the first few months of life, is more common.

Risk factors for bilirubin neurotoxicityIsoimmune hemolytic disease

G6PD deficiency

Asphyxia

Sepsis

Acidosis

Albumin less than 3.0 g/dL
Data from Maisels MJ, Bhutani VK, Bogen D, et al. Hyperbilirubinemia in the newborn infant > or 535 weeks’ gestation: an update with clarifications. Pediatrics 2009; 124:1193–8.

Polycythemia

Polycythemia (venous hematocrit 65%) in seen in infants across a range of conditions associated with active erythropoiesis or passive transfusion.76,77 They include, among others, placental insufficiency, the infant of a diabetic mother, recipient in twin-twin transfusion syndrome, and several aneuploidies, including trisomy. The clinical concern related to polycythemia is the risk for microcirculatory complications of hyperviscosity. However, determining which polycythemic infants are hyperviscous and when to intervene is a challenge.

 

 

Liver

Metabolic disorders presenting as liver disease

Germaine Pierre, Efstathia Chronopoulou
Paediatrics and Child Health 2013; 23(12): 509-514
The liver is a highly metabolically active organ and many inherited metabolic disorders have hepatic manifestations. The clinical presentation in these patients cannot usually be distinguished from liver disease due to acquired causes like infection, drugs or hematological disorders. Manifestations include acute and chronic liver failure, cholestasis and hepatomegaly. Metabolic causes of acute liver failure in childhood can be as high as 35%. Certain disorders like citrin deficiency and Niemann-Pick C disease may present in infancy with self-limiting cholestasis before presenting in later childhood or adulthood with irreversible disease. This article reviews important details from the history and clinical examination when evaluating the pediatric patient with suspected metabolic disease, the specialist and genetic tests when investigating, and also discusses specific disorders, their clinical course and treatment. The role of liver transplantation is also briefly discussed. Increased awareness of this group of disorders is important as in many cases, early diagnosis leads to early intervention with improved outcome. Diagnosis also allows genetic counselling and future family planning.

Adult liver disorders caused by inborn errors of metabolism: Review and update

Sirisak Chanprasert, Fernando Scaglia
Molecular Genetics and Metabolism 114 (2015) 1–10
http://dx.doi.org/10.1016/j.ymgme.2014.10.011

Inborn errors of metabolism (IEMs) are a group of genetic diseases that have protean clinical manifestations and can involve several organ systems. The age of onset is highly variable but IEMs afflict mostly the pediatric population. However, in the past decades, the advancement in management and new therapeutic approaches have led to the improvement in IEM patient care. As a result, many patients with IEMs are surviving into adulthood and developing their own set of complications. In addition, some IEMs will present in adulthood. It is important for internists to have the knowledge and be familiar with these conditions because it is predicted that more and more adult patients with IEMs will need continuity of care in the near future. The review will focus on Wilson disease, alpha-1 antitrypsin deficiency, citrin deficiency, and HFE-associated hemochromatosis which are typically found in the adult population. Clinical manifestations and pathophysiology, particularly those that relate to hepatic disease as well as diagnosis and management will be discussed in detail.

Inborn errors of metabolism (IEMs) are a group of genetic diseases characterized by abnormal processing of biochemical reactions, resulting in accumulation of toxic substances that could interfere with normal organ functions, and failure to synthesize essential compounds. IEMs are individually rare, but collectively numerous. The clinical presentations cover a broad spectrum and can involve almost any organ system. The age of onset is highly variable but IEMs afflict mostly the pediatric population.

Wilson disease is an autosomal recessive genetic disorder of copper metabolism. It is characterized by an abnormal accumulation of inorganic copper in various tissues, most notably in the liver and the brain, especially in the basal ganglia. The disease was first described in 1912 by Kinnier Wilson, and affects between 1 in 30,000 and 1 in 100,000 individuals. Clinical features are variable and depend on the extent  and the severity of copper deposition. Typically, patients tend to develop hepatic disease at a younger age than the neuropsychiatric manifestations. Individuals withWilson disease eventually succumb to complications of end stage liver disease or become debilitated from neurological problems, if they are left untreated.

The clinical presentations of Wilson disease are varied affecting many organ systems. However, the overwhelming majority of cases display hepatic and neurologic symptoms. In general, patients with hepatic disease present between the first and second decades of life although patients as young as 3 years old or over 50 years old have also been reported. The most common modes of presentations are acute self-limited hepatitis and chronic active hepatitis that are indistinguishable from other hepatic disorders although liver aminotransferases are generally much lower than in autoimmune or viral hepatitis. Acute fulminant hepatic failure is less common but is observed in approximately 3% of all cases of acute liver failure. Symptoms of acute liver failure include jaundice, coagulopathy, and hepatic encephalopathy. Cirrhosis can develop over time and may be clinically silent. Hepatocellular carcinoma (HCC) is rarely associated with Wilson disease, but may occur in the setting of cirrhosis and chronic inflammation.

Copper is an essential element, and is required for the proper functioning of various proteins and enzymes. The total body content of copper in a healthy adult individual is approximately 70–100 mg, while the daily requirements are estimated to be between 1 and 5 mg. Absorption occurs in the small intestine. Copper is taken up to the hepatocytes via the copper transporter hTR1. Once inside the cell, copper is bound to various proteins including metallothionein and glutathione, however, it is the metal chaperone, ATOX1 that helps direct copper to the ATP7B protein for intracellular transport and excretion. At the steady state, copper will be bound to ATP7B and is then incorporated to ceruloplasmin and secreted into the systemic circulation. When the cellular copper concentration arises, ATP7B protein will be redistributed from the trans-Golgi network to the prelysosomal vesicles facilitating copper excretion into the bile. The molecular defects in ATP7B lead to a reduction of copper excretion. Excess copper is accumulated in the liver causing tissue injury. The rate of accumulation of copper varies among individuals, and it may depend on other factors such as alcohol consumption, or viral hepatitis infections. If the liver damage is not severe, patients will accumulate copper in various tissues including the brain, the kidney, the eyes, and the musculoskeletal system leading to clinical disease. A failure of copper to incorporate into ceruloplasmin leads to secretion of the unsteady protein that has a shorter half-life, resulting in the reduced concentrations of ceruloplasmin seen in most patients with Wilson disease.

Wilson disease used to be a progressive fatal condition during the first half of the 20th century because there was no effective treatment available at that time. Penicillamine was the first pharmacologic agent introduced in 1956 for treating this condition. Penicillamine is a sulfhydryl-bearing amino acid cysteine doubly substituted with methyl groups. This drug acts as a chelating agent that promotes the urinary excretion of copper. It is rapidly absorbed in the gastrointestinal track, and over 80% of circulating penicillamine is excreted via the kidneys. Although it is very effective, approximately 10%–50% of Wilson disease patients with neuropsychiatric presentations may experience worsening of their symptoms, and often times the worsening symptoms may not be reversible.

Alpha1-antitrypsin deficiency

Alpha1-antitrypsin deficiency (AATD) is one of the most common genetic liver diseases in children and adults, affecting 1 in 2000 to 1 in 3000 live births worldwide. It is transmitted in an autosomal co-dominant fashion with variable expressivity. Alpha1 antitrypsin (A1AT) is a member of the serine protease inhibitor (SERPIN) family. Its function is to counteract the proteolytic effect of neutrophil elastase and other neutrophil proteases. Mutations in the SERPINA1, the gene encoding A1AT, result in changes in the protein structure with the PiZZ phenotype being the most common cause of liver and lung disease-associated AATDs. Although, it classically causes early onset chronic obstructive pulmonary disease (COPD) in adults, liver disease characterized by chronic inflammation, hepatic fibrosis, and cirrhosis is not uncommon in the adult population. Decreased plasma concentration of A1AT predisposes lung tissue to be more susceptible to injury from protease enzymes. However, the underlying mechanism of liver injury is different, and is believed to be caused by accumulation of polymerized mutant A1AT in the hepatocyte endoplasmic reticulum (ER). Currently, there is no specific treatment for liver disease-associated AATD, but A1AT augmentation therapy is available for patients affected with pulmonary involvement.

A1AT is a single-chain, 52-kDa polypeptide of approximately 394 amino acids [56]. It is synthesized in the liver, circulates in the plasma, and functions as an inhibitor of neutrophil elastase and other proteases such as cathepsin G, and proteinase 3. A1AT has a globular shape composed of two central β sheets surrounded by a small β sheet and nine α helices. The pathophysiology underlying liver disease is thought to be a toxic gain-of-function mutation associated with the PiZZ phenotypes. This hypothesis has been supported by the fact that null alleles which produce no detectable plasma A1AT, are not associated with liver disease. In addition, the transgenic mouse model of AATD PiZZ developed periodic acid-Schiff-positive diastase-resistant intrahepatic globule early in life similar to AATD patients. The PiZZ phenotype results in the blockade of the final processing of A1AT in the liver, as only 15% of the A1AT reaches the circulation whereas 85% of non-secreted protein is accumulated in the hepatocytes.

Citrin deficiency

Citrin deficiency is a relatively newly-defined autosomal recessive disease. It encompasses two different sub-groups of patients, neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and adult onset citrullinemia type 2 (CTLN 2).

AGC2 exports aspartate out of the mitochondrial matrix in exchange for glutamate and a proton. Thus, this protein has an important role in ureagenesis and gluconeogenesis. In CTLN2, a defect in this protein is believed to limit the supply of aspartate for the formation of argininosuccinate in the cytosol resulting in impairment of ureagenesis. Interestingly, the mouse model of citrin deficiency (Ctrn−/−) fails to develop symptoms of CTLN2 suggesting that the mitochondrial aspartate is not the only source of ureagenesis. However, it should be noted that the rodent liver expresses higher glycerol-phosphate shuttle activity than the human counterpart. With the intact glycerol-phosphate dehydrogenase, it can compensate for the deficiency of AGC2, as demonstrated by the AGC2 and glycerol-phosphate dehydrogenase double knock-out mice that exhibit similar features to those observed in human CTLN2.

HFE-associated hemochromatosis

HFE-associated hemochromatosis is an inborn error of iron metabolism characterized by excessive iron storage resulting in tissue and organ damage. It is the most common autosomal recessive disorder in the Caucasian population, affecting 0.3%–0.5% of individuals of Northern European descent. The term “hemochromatosis” was coined in 1889 by the German pathologist Friedrich Daniel Von Recklinghausen, who described it as bronze stain of organs caused by a blood borne pigment.

The classic clinical triad of cirrhosis, diabetes, and bronze skin pigmentation is rarely observed nowadays given the early recognition, diagnosis, and treatment of this condition. The most common presenting symptoms are nonspecific including weakness, lethargy, and arthralgia.

The liver is a major site of iron storage in healthy individuals and as such it is the organ that is universally affected in HFE-associated hemochromatosis. Elevation of liver aminotransferases indicative of hepatocyte injury is the most common mode of presentation and it can be indistinguishable from other causes of hepatitis. Approximately 15%–40% of patients with HFE-associated hemochromatosis have other liver conditions, including chronic viral hepatitis B or C infection, nonalcoholic fatty liver disease, and alcoholic liver disease.

 

The liver in haemochromatosis

Rune J. Ulvik
Journal of Trace Elements in Medicine and Biology xxx (2014) xxx–xxx
http://dx.doi.org/10.1016/j.jtemb.2014.08.005

The review deals with genetic, regulatory and clinical aspects of iron homeostasis and hereditary hemochromatosis. Hemochromatosis was first described in the second half of the 19th century as a clinical entity characterized by excessive iron overload in the liver. Later, increased absorption of iron from the diet was identified as the pathophysiological hallmark. In the 1970s genetic evidence emerged supporting the apparent inheritable feature of the disease. And finally in 1996 a new “hemochromato-sis gene” called HFE was described which was mutated in about 85% of the patients. From the year2000 onward remarkable progress was made in revealing the complex molecular regulation of iron trafficking in the human body and its disturbance in hemochromatosis. The discovery of hepcidin and ferroportin and their interaction in regulating the release of iron from enterocytes and macrophages to plasma were important milestones. The discovery of new, rare variants of non-HFE-hemochromatosis was explained by mutations in the multicomponent signal transduction pathway controlling hepcidin transcription. Inhibited transcription induced by the altered function of mutated gene products, results in low plasma levels of hepcidin which facilitate entry of iron from enterocytes into plasma. In time this leads to progressive accumulation of iron and subsequently development of disease in the liver and other parenchymatous organs. Being the major site of excess iron storage and hepcidin synthesis the liver is a cornerstone in maintaining normal systemic iron homeostasis. Its central pathophysiological role in HFE-hemochromatosis with downgraded hepcidin synthesis, was recently shown by the finding that liver transplantation normalized the hepcidin levels in plasma and there was no sign of iron accumulation in the new liver.

Gastrointestinal

Decoding the enigma of necrotizing enterocolitis in premature infants

Roberto Murgas TorrazzaNan Li, Josef Neu
Pathophysiology 21 (2014) 21–27
http://dx.doi.org/10.1016/j.pathophys.2013.11.011

Necrotizing enterocolitis (NEC) is an enigmatic disease that affects primarily premature infants. It often occurs suddenly and when it occurs, treatment attempts at treatment often fail and results in death. If the infant survives, there is a significant risk of long term sequelae including neurodevelopmental delays. The pathophysiology of NEC is poorly understood and thus prevention has been difficult. In this review, we will provide an overview of why progress may be slow in our understanding of this disease, provide a brief review diagnosis, treatment and some of the current concepts about the pathophysiology of this disease.

Necrotizing enterocolitis (NEC) has been reported since special care units began to house preterm infants .With the advent of modern neonatal intensive care approximately 40 years ago, the occurrence and recognition of the disease markedly increased. It is currently the most common and deadly gastro-intestinal illness seen in preterm infants. Despite major efforts to better understand, treat and prevent this devastating disease, little if any progress has been made during these 4 decades. Underlying this lack of progress is the fact that what is termed “NEC” is likely more than one disease, or mimicked by other diseases, each with a different etiopathogenesis.

Human gut microbiome

Human gut microbiome

Term or near term infants with “NEC” when compared to matched controls usually have occurrence of their disease in the first week after birth, have a significantly higher frequency of prolonged rupture of membranes, chorio-amnionitis, Apgar score <7 at 1 and 5 min, respiratory problems, congenital heart disease, hypoglycemia, and exchange transfusions. When a “NEC” like illness presents in term or near term infants, it should be noted that these are likely to be distinct in pathogenesis than the most common form of NEC and should be differentiated as such.

The infants who suffer primary ischemic necrosis are term or near term infants (although this can occur in preterms) who have concomitant congenital heart disease, often related to poor left ventricular output or obstruction. Other factors that have been associated with primary ischemia are maternal cocaine use, hyperviscosity caused by polycythemia or a severe antecedent hypoxic–ischemic event. Whether the dis-ease entity that results from this should be termed NEC can be debated on historical grounds, but the etiology is clearly different from the NEC seen in most preterm infants.

The pathogenesis of NEC is uncertain, and the etiology seems to be multifactorial. The “classic” form of NEC is highly associated with prematurity; intestinal barrier immaturity, immature immune response, and an immature regulation of intestinal blood flow (Fig.). Although genetics appears to play a role, the environment, especially a dysbiotic intestinal microbiota acting in concert with host immaturities predisposes the preterm infant to disruption of the intestinal epithelia, increased permeability of tight junctions, and release of inflammatory mediators that leads to intestinal mucosa injury and therefore development of necrotizing enterocolitis.

NEC is a multifactorial disease

NEC is a multifactorial disease

What causes NEC? NEC is a multifactorial disease with an interaction of several etiophathologies

It is clear from this review that there are several entities that have been described as NEC. What is also clear is that despite having some overlap in the final parts of the pathophysiologic cascade that lead to necrosis, the disease that is most commonly seen in the preterm infant is likely to have an origin that differs markedly from that seen in term infants with congenital heart disease or severe hypoxic–ischemic injury. Thus, epidemiologic studies will need to differentiate these entities, if the aim is to dissect common features that are most highly associated with development of the disease. At this juncture, we areleft with more of a population based preventative approach, where the use of human milk, evidence based feeding guide-lines, considerations for microbial therapy once these are proved safe and effective and approved as such by regulatory authorities, and perhaps even measures that prevent prematurity will have a major impact on this devastating disease.

Influenced by the microbiota, intestinal epithelial cells (IECs) elaborate cytokines

Influenced by the microbiota, intestinal epithelial cells (IECs) elaborate cytokines

Influenced by the microbiota, intestinal epithelial cells (IECs) elaborate cytokines, including thymic stromal lymphoprotein (TSLP), transforming growthfactor (TGF), and interleukin-10 (IL-10), that can influence pro-inflammatory cytokine production by dendritic cells (DC) and macrophages present in the laminapropria (GALT) and Peyer’s patches. Signals from commensal organisms may influence tissue-specific functions, resulting in T-cell expansion and regulation of the numbers of Th-1,
Th-2, and Th-3 cells. Also modulated by the microbiota, other IEC derived factors, including APRIL (a proliferation-inducing ligand),B-cell activating factor (BAFF), secretory leukocyte peptidase inhibitor (SLPI), prostaglandin E2(PGE2), and other metabolites, directly regulate functions ofboth antigen presenting cells and lymphocytes in the intestinal ecosystem. NK: natural killer cell; LN: lymph node; DC: dendritic cells.Modified from R. Sharma, C. Young, M. Mshvildadze, J. Neu, Intestinal microbiota does it play a role in diseases of the neonate? NeoReviews 10 (4) (2009)e166, with permission

Cross-talk between monocyte.macrophage cells and T.NK lymphocytes

Cross-talk between monocyte.macrophage cells and T.NK lymphocytes

Current Issues in the Management of Necrotizing Enterocolitis

Marion C. W. Henry and R. Lawrence Moss
Seminars in Perinatology, 2004; 28(3): 221-233
http://dx.doi.org:/10.1053/j.semperi.2004.03.010

Necrotizing enterocolitis is almost exclusively a disease of prematurity, with 90% of all cases occurring in premature infants and 90% of those infants weighing less than 2000 g. Prematurity is the only risk factor for necrotizing enterocolitis consistently identified in case control studies and the disease is rare in countries where prematurity is uncommon such as Japan and Sweden. When necrotizing enterocolitis does occur in full-term infants, it appears to by a somewhat different disease, typically associated with some predisposing condition.

NEC occurs in one to three in 1,000 live births and most commonly affects babies born between 30-32 weeks. It is most often diagnosed during the second week of life and occurs more often in previously fed infants. The mortality from NEC has been cited as 10% to 50% of all NEC cases. Surgical mortality has decreased over the last several decades from 70% to between 20 and 50%. The incremental cost per case of acute hospital care is estimated at $74 to 186 thousand compared to age matched controls, not including additional costs of long term care for the infants’ with lifelong morbidity. Survivors may develop short bowel syndrome, recurrent bouts of catheter-related sepsis, malabsorption, malnutrition, and TPN induced liver failure.

Although extensive research concerning the pathophysiology of necrotizing enterocolitis has occurred, a complete understanding has not been fully elucidated. The classic histologic finding is coagulation necrosis; present in over 90% of specimens. This finding suggests the importance of ischemia in the pathogenesis of NEC. Inflammation and bacterial overgrowth also are present. These findings support the assumptions by Kosloske that NEC occurs by the interaction of 3 events:

  • intestinal ischemia,
  • colonization by pathogenic bacteria and
  • excess protein substrate in the intestinal lumen.

Additionally, the immunologic immaturity of the neonatal gut has been implicated in the development of NEC. Reparative tissue changes including epithelial regeneration, formation of granulation tissue and fibrosis, and mixed areas of acute and chronic inflammatory changes suggest that the pathogenesis of NEC may involve a chronic process of injury and repair.

Premature newborns born prior to the 32nd week of gestational age may have compromised intestinal peristalsis and decreased motility. These motility problems may lead to poor clearance of bacteria, and subsequent bacterial overgrowth. Premature infants also have an immature intestinal tract in terms of immunologic immunity.

There are fewer functional B lymphocytes present and the ability to produce sufficient secretory IgA is reduced. Pepsin, gastric acid and mucus are also not produced as well in prematurity. All of these factors may contribute to the limited proliferation of intestinal flora and the decreased binding of these flora to mucosal cells (Fig).

Role of nitric oxide in the pathogenesis of NEC

Role of nitric oxide in the pathogenesis of NEC

Role of nitric oxide in the pathogenesis of NEC.

Characteristics of the immature gut leading to increased risk of necrotizing enterocolitis

Characteristics of the immature gut leading to increased risk of necrotizing enterocolitis

Characteristics of the immature gut leading to increased risk of necrotizing enterocolitis.

As understanding of the pathophysiology of necrotizing enterocolitis continues to evolve, a unifying concept is emerging. Initially, there is likely a subclinical insult leading to NEC. This may arise from a brief episode of hypoxia or infection. With colonization of the intestines, bacteria bind to the injured mucosa eliciting an inflammatory response which leads to further inflammation.

Intestinal Microbiota Development in Preterm Neonates and Effect of Perinatal Antibiotics

Silvia Arboleya, Borja Sanchez,, Christian Milani, Sabrina Duranti, et al.
Pediatr 2014;-:—).  http://dx.doi.org/10.1016/j.jpeds.2014.09.041

Objectives Assess the establishment of the intestinal microbiota in very low birth-weight preterm infants and to evaluate the impact of perinatal factors, such as delivery mode and perinatal antibiotics.
Study design We used 16S ribosomal RNA gene sequence-based microbiota analysis and quantitative polymerase chain reaction to evaluate the establishment of the intestinal microbiota. We also evaluated factors affecting the microbiota, during the first 3 months of life in preterm infants (n = 27) compared with full-term babies (n = 13).
Results Immaturity affects the microbiota as indicated by a reduced percentage of the family Bacteroidaceae during the first months of life and by a higher initial percentage of Lactobacillaceae in preterm infants compared with full term infants. Perinatal antibiotics, including intrapartum antimicrobial prophylaxis, affects the gut microbiota, as indicated by increased Enterobacteriaceae family organisms in the infants.

Human gut microbiome

Human gut microbiome

Conclusions Prematurity and perinatal antibiotic administration strongly affect the initial establishment of microbiota with potential consequences for later health.

Ischemia and necrotizing enterocolitis: where, when, and how

Philip T. Nowicki
Seminars in Pediatric Surgery (2005) 14, 152-158
http://dx.doi.org:/10.1053/j.sempedsurg.2005.05.003

While it is accepted that ischemia contributes to the pathogenesis of necrotizing enterocolitis (NEC), three important questions regarding this role subsist. First, where within the intestinal circulation does the vascular pathophysiology occur? It is most likely that this event begins within the intramural microcirculation, particularly the small arteries that pierce the gut wall and the submucosal arteriolar plexus insofar as these represent the principal sites of resistance regulation in the gut. Mucosal damage might also disrupt the integrity or function of downstream villous arterioles leading to damage thereto; thereafter, noxious stimuli might ascend into the submucosal vessels via downstream venules and lymphatics. Second, when during the course of pathogenesis does ischemia occur? Ischemia is unlikely to the sole initiating factor of NEC; instead, it is more likely that ischemia is triggered by other events, such as inflammation at the mucosal surface. In this context, it is likely that ischemia plays a secondary, albeit critical role in disease extension. Third, how does the ischemia occur? Regulation of vascular resistance within newborn intestine is principally determined by a balance between the endothelial production of the vasoconstrictor peptide endothelin-1 (ET-1) and endothelial production of the vasodilator free radical nitric oxide (NO). Under normal conditions, the balance heavily favors NO-induced vasodilation, leading to a low resting resistance and high rate of flow. However, factors that disrupt endothelial cell function, eg, ischemia-reperfusion, sustained low-flow perfusion, or proinflammatory mediators, alter the ET-1:NO balance in favor of constriction. The unique ET-1–NO interaction thereafter might facilitate rapid extension of this constriction, generating a viscous cascade wherein ischemia rapidly extends into larger portions of the intestine.

Schematic representation of the intestinal microcirculation

Schematic representation of the intestinal microcirculation

Schematic representation of the intestinal microcirculation. Small mesenteric arteries pierce the muscularis layers and terminate in the submucosa where they give rise to 1A (1st order) arterioles. 2A (2nd order) arterioles arise from the 1A. Although not shown here, these 2A arterioles connect merge with several 1A arterioles, thus generating an arteriolar plexus, or manifold that serves to pressurize the terminal downstream microvasculature. 3A (3rd order) arterioles arise from the 2A and proceed to the mucosa, giving off a 4A branch just before descent into the mucosa. This 4A vessel travels to the muscularis layers. Each 3A vessel becomes the single arteriole perfusing each villus.

Collectively, these studies indicate that disruption of endothelial cell function has the potential to disrupt the normal balance between NO and ET-1 within the newborn intestinal circulation, and that such an event can generate significant ischemia. In this context, it is important to note that NO and ET-1 each regulate the expression and activity of the other. An increased [NO] within the microvascular environment reduces ET-1 expression and compromises ligand binding to the ETA receptor (thus decreasing its contractile efficacy), while ET-1 compromises eNOS expression. Thus, factors that upset the balance between NO and ET-1 will have an immediate and direct effect on vascular tone, but also exert an additional indirect effect by extenuating the disruption of balance between these two factors.

It is not difficult to construct a hypothesis that links the perturbations of I/R and sustained low-flow perfusion with an initial inflammatory insult. Initiation of an inflammatory process at the mucosal–luminal interface could have a direct impact on villus and mucosal 3A arterioles, damaging arteriolar integrity and disrupting villus hemodynamics. Ascent of proinflammatory mediators to the submucosal 1A–2A arteriolar plexus could occur via draining venules and lymphatics, generating damage to vascular effector systems therein; these mediators might include cytokines and platelet activating factor, as these elements have been recovered from human infants with NEC. This event, coupled with a generalized loss of 3A flow throughout a large portion of the mucosal surface, could compromise flow rate within the submucosal arteriolar plexus.

Necrotizing enterocolitis: An update

Loren Berman, R. Lawrence Moss
Seminars in Fetal & Neonatal Medicine 16 (2011) 145e150
http://dx.doi.org:/10.1016/j.siny.2011.02.002

Necrotizing enterocolitis (NEC) is a leading cause of death among patients in the neonatal intensive care unit, carrying a mortality rate of 15e30%. Its pathogenesis is multifactorial and involves an over reactive response of the immune system to an insult. This leads to increased intestinal permeability, bacterial translocation, and sepsis. There are many inflammatory mediators involved in this process, but thus far none has been shown to be a suitable target for preventive or therapeutic measures. NEC usually occurs in the second week of life after the initiation of enteral feeds, and the diagnosis is made based on physical examination findings, laboratory studies, and abdominal radiographs. Neonates with NEC are followed with serial abdominal examinations and radiographs, and may require surgery or primary peritoneal drainage for perforation or necrosis. Many survivors are plagued with long term complications including short bowel syndrome, abnormal growth, and neurodevelopmental delay. Several evidence-based strategies exist that may decrease the incidence of NEC including promotion of human breast milk feeding, careful feeding advancement, and prophylactic probiotic administration in at-risk patients. Prevention is likely to have the greatest impact on decreasing mortality and morbidity related to NEC, as little progress has been made with regard to improving outcomes for neonates once the disease process is underway.

Immune Deficiencies

Primary immunodeficiencies: A rapidly evolving story

Nima Parvaneh, Jean-Laurent Casanova,  LD Notarangelo, ME Conley
J Allergy Clin Immunol 2013;131:314-23.
http://dx.doi.org/10.1016/j.jaci.2012.11.051

The characterization of primary immunodeficiencies (PIDs) in human subjects is crucial for a better understanding of the biology of the immune response. New achievements in this field have been possible in light of collaborative studies; attention paid to new phenotypes, infectious and otherwise; improved immunologic techniques; and use of exome sequencing technology. The International Union of Immunological Societies Expert Committee on PIDs recently reported on the updated classification of PIDs. However, new PIDs are being discovered at an ever-increasing rate. A series of 19 novel primary defects of immunity that have been discovered after release of the International Union of Immunological Societies report are discussed here. These new findings highlight the molecular pathways that are associated with clinical phenotypes and suggest potential therapies for affected patients.

Combined Immunodeficiencies

  • T-cell receptor a gene mutation: T-cell receptor ab1 T-cell depletion

T cells comprise 2 distinct lineages that express either ab or gd T-cell receptor (TCR) complexes that perform different tasks in immune responses. During T-cell maturation, the precise order and efficacy of TCR gene rearrangements determine the fate of the cells. Productive β-chain gene rearrangement produces a pre-TCR on the cell surface in association with pre-Tα invariant peptide (β-selection). Pre-TCR signals promote α-chain recombination and transition to a double-positive stage (CD41CD81). This is the prerequisite for central tolerance achieved through positive and negative selection of thymocytes.

  • Ras homolog gene family member H deficiency: Loss of naive T cells and persistent human papilloma virus infections
  • MST1 deficiency: Loss of naive T cells

New insight into the role of MST1 as a critical regulator of T-cell homing and function was provided by the characterization of 8 patients from 4 unrelated families who had homozygous nonsense mutations in STK4, the gene encoding MST1. MST1 was originally identified as an ubiquitously expressed kinase with structural homology to yeast Ste. MST1 is the mammalian homolog of the Drosophila Hippo protein, controlling cell growth, apoptosis, and tumorigenesis. It has both proapoptotic and antiapoptotic functions.

  • Lymphocyte-specific protein tyrosine kinase deficiency: T-cell deficiency with CD41 lymphopenia

Defects in pre-TCR– and TCR-mediated signaling lead to aberrant T-cell development and function (Fig). One of the earliest biochemical events occurring after engagement of the (pre)-TCR is the activation of lymphocyte-specific protein tyrosine kinase (LCK), a member of the SRC family of protein tyrosine kinases. This kinase then phosphorylates immunoreceptor tyrosine-based activation motifs of intracellular domains of CD3 subunits. Phosphorylated immunoreceptor tyrosine-based activation motifs recruit z-chain associated protein kinase of 70 kDa, which, after being phosphorylated by LCK, is responsible for activation of critical downstream events. Major consequences include activation of the membrane-associated enzyme phospholipase Cg1, activation of the mitogen-activated protein kinase, nuclear translocation of nuclear factor kB (NFkB), and Ca21/Mg21 mobilization. Through these pathways, LCK controls T-cell development and activation. In mice lacking LCK, T-cell development in the thymus is profoundly blocked at an early double-negative stage.

TCR signaling

TCR signaling

TCR signaling. Multiple signal transduction pathways are stimulated through the TCR. These pathways collectively activate transcription factors that organize T-cell survival, proliferation, differentiation, homeostasis, and migration. Mutant molecules in patients with TCR-related defects are indicated in red.

  • Uncoordinated 119 deficiency: Idiopathic CD41 lymphopenia

Idiopathic CD41 lymphopenia (ICL) is a very heterogeneous clinical entity that is defined, by default, by persistent CD41 T-cell lymphopenia (<300 cells/mL or <20% of total T cells) in the absence of HIV infection or any other known cause of immunodeficiency.

Well-Defined Syndromes with Immunodeficiency

  • Wiskott-Aldrich syndrome protein–interacting protein deficiency: Wiskott-Aldrich syndrome-like phenotype

In hematopoietic cells Wiskott-Aldrich syndrome protein (WASP) is stabilized through forming a complex with WASP interacting protein (WIP).

  • Phospholipase Cg2 gain-of-function mutations: Cold urticaria, immunodeficiency, and autoimmunity/autoinflammatory

This is a unique phenotype, sharing features of antibody deficiency, autoinflammatory diseases, and immune dysregulatory disorders, making its classification difficult. Two recent studies validated the pleiotropy of genetic alterations in the same gene.

Predominantly Antibody Defects

  • Defect in the p85a subunit of phosphoinositide 3-kinase: Agammaglobulinemia and absent B cells
  • CD21 deficiency: Hypogammaglobulinemia
  • LPS-responsive beige-like anchor deficiency:
  • Hypogammaglobulinemia with autoimmunity and

early colitis

Defects Of Immune Dysregulation

  • Pallidin deficiency: Hermansky-Pudlak syndrome type 9
  • CD27 deficiency: Immune dysregulation and
  • persistent EBV infection

Congenital Defects Of Phagocyte Number, Function, Or Both

  • Interferon-stimulated gene 15 deficiency: Mendelian susceptibility to mycobacterial diseases

Defects In Innate Immunity

  • NKX2-5 deficiency: Isolated congenital asplenia
  • Toll/IL-1 receptor domain–containing adaptor inducing IFN-b and TANK-binding kinase 1 deficiencies: Herpes simplex encephalitis
  • Minichromosome maintenance complex component 4 deficiency: NK cell deficiency associated with growth retardation and adrenal insufficiency

Autoinflammatory Disorders

  • A disintegrin and metalloproteinase 17 deficiency: Inflammatory skin and bowel disease

 

Cross-talk between monocyte.macrophage cells and T.NK lymphocytes

Cross-talk between monocyte.macrophage cells and T.NK lymphocytes

Cross-talk between monocyte/macrophage cells and T/NK lymphocytes. Genes in the IL-12/IFN-g pathway are particularly important for protection against mycobacterial disease. IRF8 is an IFN-g–inducible transcription factor required for the induction of various target genes, including IL-12. The NF-kB essential modulator (NEMO) mutations in the LZ domain impair CD40-NEMO–dependent pathways. Some gp91phox mutations specifically abolish the respiratory burst in monocyte-derived macrophages. ISG15 is secreted by neutrophils and potentiates IFN-g production by NK/T cells. Genetic defects that preclude monocyte development (eg, GATA2) can also predispose to mycobacterial infections (not shown). Mutant molecules in patients with unusual susceptibility to infection are indicated in red.

The field of PIDs is advancing at full speed in 2 directions. New genetic causes of known PIDs are being discovered (eg, CD21 and TRIF). Moreover, new phenotypes qualify as PIDs with the identification of a first genetic cause (eg, generalized pustular psoriasis). Recent findings contribute fundamental knowledge about immune system biology and its perturbation in disease. They are also of considerable clinical benefit for the patients and their families. A priority is to further translate these new discoveries into improved diagnostic methods and more effective therapeutic strategies, promoting the well-being of patients with PIDs.

Primary immunodeficiencies

Luigi D. Notarangelo
J Allergy Clin Immunol 2010; 125(2): S182-194
http://dx.doi.org:/10.1016/j.jaci.2009.07.053

In the last years, advances in molecular genetics and immunology have resulted in the identification of a growing number of genes causing primary immunodeficiencies (PIDs) in human subjects and a better understanding of the pathophysiology of these disorders. Characterization of the molecular mechanisms of PIDs has also facilitated the development of novel diagnostic assays based on analysis of the expression of the protein encoded by the PID-specific gene. Pilot newborn screening programs for the identification of infants with severe combined immunodeficiency have been initiated. Finally, significant advances have been made in the treatment of PIDs based on the use of subcutaneous immunoglobulins, hematopoietic cell transplantation from unrelated donors and cord blood, and gene therapy. In this review we will discuss the pathogenesis, diagnosis, and treatment of PIDs, with special attention to recent advances in the field.

 

 

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Graft-versus-Host Disease

Writer and Curator: Larry H. Bernstein, MD, FCAP 

 

Introduction

This piece is a follow up to the article on allogeneic transfusion reactions, which extends into transplantation and transplantation outcomes for hematological diseases, both malignant and nonmalignant. The safety of transfusions in Western countries has improved substantially, and the causes for transfusion mishaps has been reduced to unexpected infectious sources, uncommon immune incompatibilities, and errors in processing the blood products.  The greatest risk is incurred in platelet transfusions because of the short shelf-life of the product, and the time needed for testing prior to release.  This portion of the review is concerned with Graft-versus-Host Disease, which is unique to transfusion and transplanting of blood. In other transplantation, there is graft failure because of host versus graft incompatibility or complications.  The reverse order applies to blood.  In this case, on the contrary, the transfused or grafted donor tissue becomes a pursuer after the recipients hematopoietic cells.

Peter Brian Medawar: Father of Transplantation

Thomas E. Starzl, M.D., PH.D., F.A.C.S.
J Am Coll Surg. 1995 Mar; 180(3): 332–336

Most of the surgical specialities can be tracked to the creative vision of a surgeon. Transplantation is an exception. Here, the father of the field is succinctly defined in the dictionary as: “Peter Brian Medawar: a Brazilian born British Zoologist who at the age of 45 shared a 1960 Nobel Prize for his work on acquired immunologic tolerance”. Medawar was mysteriously overwhelming to many colleagues and observers, even when he was young. He was the son of a Lebanese father and an English mother—tall, athletic, abnormally handsome, hypnotically articulate in public, and politely cordial in his personal relations. In September 1969, at the age of 54, he had the first of a series of strokes. These crippled him physically but not in spirit. Although I saw Medawar often professionally and privately over a 22 year period, before and after he was disabled, this sporadic exposure was not enough to understand him. My sense is that no one did, except perhaps Jean, his wife for nearly 50 years.

Medawar’s dazzling personality before and great courage after his strokes was inspirational, but his fame was based on the unique achievement in 1953 captured by the terse dictionary mention of “acquired immunologic tolerance.” The roots leading to this accomplishment had fed on the blood of war. More than 12 years earlier, the recently wed zoologist Medawar—24 years of age and fresh from graduate studies at Oxford University—was assigned to
the service of the British surgeon, Dr. Thomas Gibson, to determine if skin allografts could be used to treat casualties from the Battle of Britain. First,
in human studies with Gibson, and then with simple and logical rabbit experiments, Medawar showed that rejection of the skin was an immunologic phenomenon. This later was shown  to be analogous to the cell-mediated delayed hypersensitivity that confers immunity to diseases such as tuberculosis. The principal evidence in the early studies was that repetitive grafts from the same donor were rejected more rapidly with each successive attempt —the sensitization and donor specificity confirming an earlier clinical observations by Emil Holman of Stanford in skin-grafted burn victims. Once it was established that rejection was an immune reaction, strategies began to evolve to weaken the recipient immune system. By 1953, total body irradiation and adrenal cortical steroids had been shown to delay skin rejection. However, this immunosuppressive effect was either minor if the animals survived, or lethal to the recipient if the grafts were spared.

Bombshell

In the resulting atmosphere of nihilism about clinical applications, a three and one-half page article by Billingham, Brent, and Medawar in the October 3, 1953 issue of Nature describing acquired tolerance, came as a blinding beacon of hope. The three men had learned that donor splenocytes could be engrafted by their intravenous infusion into immunologically immature mice in utero or perinatally. When these inoculated recipients matured, they could accept skin and other tissues from the donor (but from no other) mouse strain. The immune system of the recipients had been populated by the immunocytes of the donor, meaning that they were now chimeras. The race was on to convert this principle to humans. However, the dark side of their accomplishment soon was revealed by the two younger members of Medawar’s team, Billingham and Brent and by the Dane, Simonsen. The engrafted donor cells could turn the tables and reject the defenseless recipient unless the tissue match was a good one. This was the dreaded graft versus host disease (GVHD) in which transplanted donor cells attacked the recipient skin, gastrointestinal tract, lungs, liver, and the bone marrow itself. Medawar’s dream of 1953 was suddenly a nightmare. Or was it?

On the contrary, the work took a straight line to clinical application, after the demonstration by Prehn and Main that similar tolerance could be induced in adult mice rendered immunologically defenseless by total body irradiation before splenocyte (or later bone marrow) infusion. The recipient conditioning, known as cytoablation, also could be accomplished with myelotoxic drugs. However, as Billingham, Brent, and Medawar had predicted, donor specific tolerance could be induced in humans without GVHD only if there was a good tissue (HLA) match. In 1968, 15 years after the epic Billingham, Brent and Medawar publication, Robert Good and Fritz Bach reported the first two successful human bone marrow transplants. Both recipients of well matched bone marrow from blood relatives are still alive. This was a triumph in which the principal clinicians were internists, as summarized 25 years later in the acceptance speech by the 1990 Nobel Laureate Donnall Thomas.

The growth of bone marrow and whole organ transplantation

The growth of bone marrow and whole organ transplantation

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2681237/bin/nihms-87975-f0001.gif

The growth of bone marrow (right) and whole organ transplantation (left) from the seed planted by Peter Medawar during World War II. GVHD, Graft versus host disease.

Immunological Tolerance: Medawar Nobel Acceptance Lecture

“Immunological tolerance” may be described as a state of indifference or non-reactivity towards a substance that would normally be expected to excite an immunological response. The term first came to be used in the context of tissue transplantation immunity, i.e. of the form of immunity that usually prohibits the grafting of tissues between individuals of different genetic make-up; and it was used to refer only to a non-reactivity caused by exposing animals to antigenic stimuli before they were old enough to undertake an immunological response. For example, if living cells from a mouse of strain CBA are injected into an adult mouse of strain A, the CBA cells will be destroyed by an immunological process, and the A-line mouse that received them will destroy any later graft of the same origin with the speed to be expected of an animal immunologically forearmed. But if the CBA cells are injected into a foetal or newborn A-line mouse, they are accepted; more than that, the A-line mouse, when it grows up, will accept any later graft from a CBA donor as if it were its own. I shall begin by using the term “immunological tolerance” in the rather restricted sense that is illustrated by this experiment, and shall discuss its more general usage later on.

The experiment I have just described can be thought of as an artificial reproduction of an astonishing natural curiosity, the phenomenon of red-cell chimerism in certain dizygotic twins. The blood systems of twin cattle before birth are not sharply distinct from each other, as they are in most other twins; instead, the blood systems make anastomoses with each other, with the effect that the twins can indulge in a prolonged exchange of blood before birth. In 1945, R.D. Owen2 made the remarkable discovery that most twin cattle are born with, and may retain throughout life, a stable mixture – not necessarily a fifty-fifty mixture – of each other’s red cells; it followed, then, that the twin cattle must have exchanged red-cell precursors and not merely red cells in their mutual transfusion before birth. This is the first example of the phenomenon we came to call immunological tolerance; the red cells could not have “adapted” themselves to their strange environment, because they were in fact identified as native or foreign by those very antigenie properties which, had an adaptation occurred, must necessarily have been transformed. A few years later R.E. Billingham and I3, with the help of three members of the scientific staff of the Agricultural Research Council, showed that most dizygotic cattle twins would accept skin grafts from each other, and that this mutual tolerance was specific, for skin transplanted from third parties was cast off in the expected fashion.

Some properties of the tolerant state

The main points that emerged from our analysis of the tolerant state were these. In the first place, tolerance must be due to an alteration of the host, not to an antigenic adaptation of the grafted cells, for grafts newly transplanted in adult life have no opportunity to adapt themselves, and the descendants of the cells injected into foetal or newborn animals can be shown by N.A. Mitcbison’s methods to retain their antigenic power10. Once established, the state of tolerance is systemic; if one part of the body will tolerate a foreign graft, so will another; we found no evidence that a tolerated graft builds up a privileged position for itself within its own lymphatic territory. The stimulus that is responsible for instating tolerance is an antigenic stimulus – one which, had it been applied to older animals, would have caused them to become sensitive or immune. A plural stimulus can induce plural tolerance; the donor will usually contain several important antigens that are lacking in the recipient, and long-lasting tolerance must imply tolerance of them all. The state of tolerance is specific in the sense that it will discriminate between one individual and another, for an animal made tolerant of grafts from one individual will not accept grafts from a second individual unrelated to the first; but it will not discriminate between one tissue and another from the same donor.

Tolerance and auto-immunity: 50 years after Burnet.

Martini A1, Burgio GR
Eur J Pediatr. 1999 Oct;158(10):769-75.

Fifty years ago Sir F. Macfarlane Burnet published his first fundamental contribution to the theory of immune tolerance he perfected 10 years later. Since then an impressive amount of new information on the function of the immune system has been gathered. As any original meaningful theory, Burnet’s hypothesis on the development of immune tolerance has undergone extensive modifications to take into account all these new findings. An improved understanding of the mechanisms of tolerance has led to new possibilities for the treatment of auto-immune diseases.

Clonal Selection
http://en.wikipedia.org/wiki/Clonal_selection

Clonal selection theory is a scientific theory in immunology that explains the functions of cells (lymphocytes) of the immune system in response to specific antigens invading the body. The concept was introduced by an Australian doctor Frank Macfarlane Burnet in 1957 in an attempt to explain the formation of a diversity of antibodies during initiation of the immune response. The theory has become a widely accepted model for how the immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens.

The theory states that in a pre-existing group of lymphocytes (specifically B cells), a specific antigen only activates (i.e. selection) its counter-specific cell so that particular cell is induced to multiply (producing its clones) for antibody production. In short the theory is an explanation of the mechanism for the generation of diversity of antibody specificity. The first experimental evidence came in 1958, when Gustav Nossal and Joshua Lederberg showed that one B cell always produces only one antibody. The idea turned out to be the foundation of molecular immunology, especially in adaptive immunity.

The fundamental contribution of Robert A. Good to the discovery of the crucial role of thymus in mammalian immunity

Domenico Ribatti
Immunology. 2006 Nov; 119(3): 291–295.
http://dx.doi.org:/10.1111/j.1365-2567.2006.02484.x

Robert Alan Good was a pioneer in the field of immunodeficiency diseases. He and his colleagues defined the cellular basis and functional consequences of many of the inherited immunodeficiency diseases. His was one of the groups that discovered the pivotal role of the thymus in the immune system development and defined the separate development of the thymus-dependent and bursa-dependent lymphoid cell lineages and their responsibilities in cell-mediated and humoral immunity.  Keywords: bursa of Fabricius, history of medicine, immunology, thymus

Robert Alan Good (May 21, 1922 – June 13, 2003) was an American physician who performed the first successful human bone marrow transplant

Robert A. Good began his intellectual and experimental queries related to the thymus in 1952 at the University of Minnesota, initially with pediatric patients. However, his interest in the plasma cell, antibodies and the immune response began in 1944, while still in Medical School at the University of Minnesota in Minneapolis, with his first publication appearing in 1945.

Idiopathic Acquired Agammaglobulinemia Associated with Thymoma (1953)

  • a markedly deficient ability to produce antibodies and significant deficits of all or most of the cell-mediated immunities
  • in no instance did removal of the thymic tumour restore immunological function or correct the protein deficit

Good syndrome: thymoma with immunodeficiency

  • increased susceptibility to bacterial infections by encapsulated organisms and opportunistic viral and fungal infections
  • immunodeficiencies, leukopenia, lymphopenia and eosinophylopenia
  • severely hypogammaglobulinemic rather than agammaglobulinemic

Good and others found that the patients lacked all of the subsequently described immunoglobulins. These patients were found not to have plasma cells or germinal centers in their hematopoietic and lymphoid tissues. They possessed circulating lymphocytes in normal numbers.

Speculation on the reason for immunological failure following neonatal thymectomy has centered on the thymus as a source of cells or humoral factors essential to normal lymphoid development and immunological maturation.

The bursa of Fabricius and the thymus are ‘central lymphoid organs’ in the chicken, essential to the ontogenetic development of adaptive immunity in that species. Studies by Papermaster and co-workers in Good’s laboratory34,35 indicated that bursectomy in the newly hatched chicks did not completely abolish immunological potential in the adult animal but rather produced a striking quantitative reduction insufficient to eliminate the homograft reaction. The failure of thymectomy in newly hatched chicks to alter the immunological potential of the maturing animal probably only reflected the participation of the bursa of Fabricius in the development of full immunological capacity.

Bursectomized and irradiated birds were completely devoid of germinal centers, plasma cells and the capacity to make antibodies yet they had perfectly normal development of thymocytes and lymphocytes elsewhere in the body that mediated cellular immune reactions. On the other hand, thymectomized and irradiated animals were deficient in lymphocytes that mediated cellular immunity as assessed by skin graft rejection, delayed-type hypersensitivity and graft versus host assays, but they still produced germinal centers, plasma cells and circulating immunoglobulins.

 

Graft vs Host Disease

Graft-versus-host disease (GVHD) is a complication that can occur after a stem cell or bone marrow transplant. With GVHD, the newly transplanted donor cells attack the transplant recipient’s body.

Graft-versus-host disease (GVHD) is a common complication following an allogeneic tissue transplant. It is commonly associated with stem cell or bone marrow transplant but the term also applies to other forms of tissue graft. Immune cells (white blood cells) in the tissue (the graft) recognize the recipient (the host) as “foreign“. The transplanted immune cells then attack the host’s body cells. GVHD can also occur after a blood transfusion if the blood products used have not been irradiated or treated with an approved pathogen reduction system.

http://en.wikipedia.org/wiki/Graft-versus-host_disease

Causes

GVHD may occur after a bone marrow or stem cell transplant in which someone receives bone marrow tissue or cells from a donor. This type of transplant is called allogeneic. The new, transplanted cells regard the recipient’s body as foreign. When this happens, the newly transplanted cells attack the recipient’s body.

GVHD does not occur when someone receives his or her own cells during a transplant. This type of transplant is called autologous.

Before a transplant, tissue and cells from possible donors are checked to see how closely they match the person having the transplant. GVHD is less likely to occur, or symptoms will be milder, when the match is close. The chance of GVHD is:

  • Around 30 – 40% when the donor and recipient are related
  • Around 60 – 80% when the donor and recipient are not related

There are two types of GVHD: acute and chronic. Symptoms in both acute and chronic GVHD range from mild to severe.

  • Acute GVHD usually happens within the first 6 months after a transplant.
  • Chronic GVHD usually starts more than 3 months after a transplant, and can last a lifetime.

Bone marrow transplant

A bone marrow transplant is a procedure to replace damaged or destroyed bone marrow with healthy bone marrow stem cells.  Stem cells are immature cells in the bone marrow that give rise to all of your blood cells.

There are three kinds of bone marrow transplants:

  • Autologous bone marrow transplant: The term auto means self. Stem cells are removed from you before you receive high-dose chemotherapy or radiation treatment. The stem cells are stored in a freezer (cryopreservation). After high-dose chemotherapy or radiation treatments, your stems cells are put back in your body to make (regenerate) normal blood cells. This is called a rescue transplant.
  • Allogeneic bone marrow transplant: The term allo means other. Stem cells are removed from another person, called a donor. Most times, the donor’s genes must at least partly match your genes. Special blood tests are done to see if a donor is a good match for you. A brother or sister is most likely to be a good match. Sometimes parents, children, and other relatives are good matches. Donors who are not related to you may be found through national bone marrow registries.
  • Umbilical cord blood transplant: This is a type of allogeneic transplant. Stem cells are removed from a newborn baby’s umbilical cord right after birth. The stem cells are frozen and stored until they are needed for a transplant. Umbilical cord blood cells are very immature so there is less of a need for matching. But blood counts take much longer to recover.

Before the transplant, chemotherapy, radiation, or both may be given. This may be done in two ways:

  • Ablative (myeloablative) treatment: High-dose chemotherapy, radiation, or both are given to kill any cancer cells. This also kills all healthy bone marrow that remains, and allows new stem cells to grow in the bone marrow.
  • Reduced intensity treatment, also called a mini transplant: Patients receive lower doses of chemotherapy and radiation before a transplant. This allows older patients, and those with other health problems to have a transplant.

Histocompatibility antigen:

  • A histocompatibility antigen blood test looks at proteins called human leukocyte antigens (HLAs). These are found on the surface of almost all cells in the human body. HLAs are found in large amounts on the surface of white blood cells. They help the immune system tell the difference between body tissue and substances that are not from your own body.

http://www.nlm.nih.gov/medlineplus/ency/article/001309.htm

Induction of transplantation tolerance in haploidenical transplantation under reduced intensity conditioning: The role of ex-vivo generated donor CD8+ T cells with central memory phenotype

Eran Ophir, Y Eidelstein, E Bachar-Lustig, D Hagin, N Or-Geva, A Lask, , Y Reisner
Best Practice & Research Clinical Haematology 24 (2011) 393–401
http://dx.doi.org:/10.1016/j.beha.2011.05.007

Haploidentical hematopoietic stem cell transplantation (HSCT) offers the advantage of readily available family member donors for nearly all patients. A ‘megadose’ of purified CD34þ hematopoietic stem cells is used to overcome the host’s residual immunity surviving the myeloablative conditioning, while avoiding severe GVHD. However, the number of CD34+ cells that can be harvested is insufficient for overcoming the large numbers of host T cells remaining after reduced intensity conditioning (RIC). Therefore, combining a ‘megadose’ of CD34+ HSCT with other tolerizing cells could potentially support and promote successful engraftment of haploidentical purified stem cell transplantation under a safer RIC. One approach to address this challenge
could be afforded by using Donor CD8 T cells directed against 3rd-party stimulators, bearing an ex-vivo induced central memory phenotype (Tcm). These Tcm cells, depleted of GVH reactivity, were shown to be highly
efficient in overcoming host T cells mediated rejection and in promoting
fully mismatched bone-marrow (BM) engraftment, in HSCT murine models.
This is likely due to the marked lymph node homing of the Tcm, their strong proliferative capacity and prolonged persistence in BM transplant recipients. Thus, combining anti 3rd-party Tcm cell therapy with a ‘megadose’ of purified CD34+ stem cells, could offer a safer RIC protocol for attaining hematopoietic chimerism in patients with hematological diseases and as a platform for organ transplantation or cell therapy in cancer patients.

Induction of tolerance in organ recipients by hematopoietic stem cell transplantation

Eran Ophir, Yair Reisner
International Immunopharmacology 9 (2009) 694–700
http://dx.doi.org:/10.1016/j.intimp.2008.12.009

The use of hematopoietic stem cell transplantation (HSCT) for the establishment of mixed chimerism represents a viable and attractive approach for generating tolerance in transplantation biology, as it generally leads to durable immune tolerance, enabling the subsequent engraftment of organ transplants without the need for a deleterious continuous immunosuppressive therapy. However, in order to apply HSCT to patients in a manner that enables long term survival, transplant-related mortality must be minimized by eliminating the risk for graft-versus-host-disease (GVHD) and by reducing the toxicity of the conditioning protocol. T-cell depleted bone marrow transplants (TDBMT) have been shown to adequately eliminate GVHD. However, even in leukemia patients undergoing supralethal conditioning, mismatched TDBMT are vigorously rejected. This barrier can be overcome through the modulatory activity of CD34 cells, which are endowed with veto activity, by the use of megadose stem cell transplants. In mice, megadoses of Sca+linhematopoietic stem cells can induce mixed chimerism following sub-lethal conditioning. Nevertheless, the number of human CD34 cells that can be harvested is not likely to be sufficient to overcome rejection under reduced intensity conditioning (RIC), which might be acceptable in recipients of organ transplantation. To address this challenge, we investigated a novel source of veto cells, namely anti 3rd-party cytotoxic T cells (CTLs) which are depleted of GVH reactivity, combined with megadoses of purified stem cells and a RIC protocol. This approach might provide a safer modality for the induction of durable chimerism.

Intrinsic unresponsiveness of Mertk/B cells to chronic graft-versus-host disease is associated with unmodulated CD1d expression

Wen-Hai Shao, Y Zhen, FD Finkelman, RA Eisenberg, PL Cohen
Journal of Autoimmunity 39 (2012) 412e419
http://dx.doi.org/10.1016/j.jaut.2012.07.001

Activation and migration of marginal zone B (MZB) cells into follicular (FO) regions of the spleen has been proposed as one of the mechanisms that regulate the development of autoreactive B cells. The mer receptor tyrosine kinase (Mertk) mediates apoptotic cell clearance and regulates activation and cytokine secretion. In the well-studied class II chronic GVH model of bm12 cells into B6 hosts, we observed that Mertk deficient B6 mice did not generate autoantibodies in response to this allogeneic stimulus. We posited that Mertk is important in MHC-II-mediated B cell signaling. In the present study, we show that B cells from Mertk-/- mice but not WT B6 mice exhibited decreased calcium mobilization and tyrosine phosphorylation when stimulated by MHC-II cross-linking. The finding that Mertk was important for class II signaling in B cells was further supported by the preponderance of a-allotype autoantibodies in cGVH in RAG-KO mice reconstituted with a mixture of bone marrow from Mertk-/-mice (b-allotype) and C20 mice (a-allotype). MZB cells from Mertk-/-  mice were unable to down regulate surface CD1d expression and subsequent inclusion in the MZ, associated with significantly lower germinal center responses compared to MZB cells from WT. Moreover, Mertk-/- mice treated with an anti-CD1d down regulating antibody responded significantly to bm12 cells, while no response was observed in Mertk-/- mice treated with control antibodies. Taken together, these findings extend the role of Mertk to include CD1d down regulation on MZB cells, a potential mechanism limiting B cell activation in cGVH.

Galectin-9 ameliorates acute GVH disease through the induction of T-cell apoptosis

Kazuki Sakai, Eri Kawata, Eishi Ashihara, Yoko Nakagawa, et al.
Eur. J. Immunol. 2011. 41: 67–75 http://dx.doi.org:/10.1002/eji.200939931

Galectins comprise a family of animal lectins that differ in their affinity for β-galactosides. Galectin-9 (Gal-9) is a tandem-repeat-type galectin that was recently shown to function as a ligand for T-cell immunoglobin domain and mucin domain-3 (Tim-3) expressed on terminally differentiated CD41 Th1 cells. Gal-9 modulates immune reactions, including the induction of apoptosis in Th1 cells. In this study, we investigated the effects of Gal-9 in murine models of acute GVH disease (aGVHD). First, we demonstrated that recombinant human Gal-9 inhibit MLR in a dose-dependent manner, involving both Ca21 influx and apoptosis in T cells. Next, we revealed that recombinant human Gal-9 significantly inhibit the progression of aGVHD in murine BM transplantation models. In conclusion, Gal-9 ameliorates aGVHD, possibly by inducing T-cell apoptosis, suggesting that gal-9 may be an attractive candidate for the treatment of aGVHD.

 

GVHD Prevention: An Ounce Is Better Than a Pound

Pavan Reddy, Gerard Socie, Corey Cutler, Daniel Weisdorf
Biol Blood Marrow Transplant 18:S17-S26, 2012  http://dx.doi.org:/10.1016/j.bbmt.2011.10.034

The pathophysiology of acute graft-versus-host disease (aGVHD) is known to involve donor T cells responding to host histoincompatible allo-antigens presented by the host antigen presenting cells (APCs) and the subsequent induction of pro-inflammatory cytokines and cellular effectors that cause target organ damage. In a more general sense, GVHD can be considered as an immune response against foreign antigens that has gone awry. Similar to all immune responses, GVHD, can be understood as a process that consists of (A) triggers, (B) sensors, (C) mediators, and (D) effectors of GVHD.

Like all immune responses, certain triggers are critical for induction of acute graft-versus-host disease (aGVHD). These include: (1) Disparities between histocompatibility antigens: antigen disparity can be at the level of major histocompatibility complex (MHC), that is, MHC mismatched or at the level of minor histocompatibility antigens (miHA), that is, MHC matched but miHA mismatched. The severity of aGVHD is directly related to the degree of M HC mismatch. In bone marrow transplants (BMT) that are MHC matched but miHA disparate, donor T cells still recognize MHC-peptide derived from the products of recipient polymorphic genes, the miHAs.

Damage induced by conditioning regimens and underlying diseases: under most circumstances, the initiation of an adaptive immune response is triggered by the innate immune response. The innate immune system is triggered by certain exogenous and endogenous molecules. This is likely the case in the induction of aGVHD. Pattern recognition receptors such as Toll-like receptors (TLR), nucleotide-binding oligomerization domain containing 2 (NOD2) play an essential role in innate immunity and in initiating the cellular signaling pathways that activate cytokine secretion, such as NF-kB. Some of their ligands, such as lipopolysaccharide, CpG, and MDP2, which is recognized by TLR-4, TLR-9, and NOD2, respectively, are released by the preparative regimens and contribute to the induction and enhancement of allo-T cell responses. In this way, the conditioning regimens amplify the secretion of proinflammatory cytokines like interleukin (IL)-1, tumor necrosis factor (TNF)-α,  IL-6, and other interferon family members in a process described as a ‘‘cytokine storm.’’

The triggers that initiate an immune response have to be sensed and presented. APCs might be considered the sensors for aGVHD. The APCs sense the DAMPs, present the MHC disparate or miHA disparate protein, and provide the critical secondary (costimulatory) and tertiary (cytokine) signals for activation of the alloreactive T cells, the mediators of aGVHD. APCs sense allo-disparity through MHC and peptide complexes. Dendritic cells (DCs) are the most potent APCs and the primary sensors of allo-disparity.

APCs provide the critical costimulation signals for turning on the aGVHD process. The interaction between the MHC/allopeptide complex on APCs and the T cell receptor of donor T cells along with the signal via T cell costimulatory molecules and their ligands on APCs is required to achieve T cell activation, proliferation, differentiation, and survival and the in vivo blockade of positive costimulatory molecules (such as CD28, ICOS, CD40, CD30, etc.), or inhibitory signals (such as PD-1 and CTLA-4) mitigate or exacerbate aGVHD, respectively.

Evidence suggests that alloreactive donor T cells consist of several subsets with different stimuli responsiveness, activation thresholds, and effector functions.

The allo-antigen composition of the host determines which donor T cells subsets differentiate and proliferate. As mentioned previously, in the majority of HLA-matched HCT, aGVHD may be induced by either or both CD41 and CD81 subsets responses to miHAs. The repertoire and immunodominance of the GVHD-associated peptides presented by MHC class I and class II molecules has not been defined. Donor naive CD62L1 T cells are the primary alloreactive T cells that drive the GVHD reaction while the donor effector memory CD62L2 T cells do not. Interestingly, donor regulatory T cells (Tregs) expressing CD62L are also critical to the regulation of GVHD. We now know that it is possible to modulate the alloreactivity of na€ıve T cells by inducing anergy with costimulation blockade, deletion via cytokine modulation, or mixed chimerism. Donor effector memory T cells that are nonalloreactive do not induce GVHD, yet are able to transfer functional memory. In contrast, memory T cells that are alloreactive can cause severe GVHD.

The effector phase that leads to GVHD target organ damage is a complex cascade that involves cytolytic cellular effectors such as CD8 cytotoxic T lymphocytes (CTLs), CD4 T cells, natural killer cells, and inflammatory molecules such as IL-1β, TNF-α, IFN-ϒ, IL-6, and reactive oxygen species. The cellular effectors require cell-cell contact to kill the cells of the target tissues via activation of perforin granzyme, Fas-FasL (CD95-CD95L), or TNFR TRAIL pathways. Other CTLs killing mechanisms such as TWEAK, and LTβ/LIGHT pathways have also been implicated in GVHD. It is important to note that
CTL pathways are essential for GVL effects as well.

All of the above aspects of the biology of aGVHD have been summarized in the mold of a normal immune response. Although this allows for accessing the biology of GVHD, it is important to note that GVHD is a complicated systemic process with as yet still many unknowns and is not a simplified, linear, or cyclical process.

Kinetics of CD4+ and CD8+ T-cell subsets in graft-versus-host reaction (GVHR) in ginbuna crucian carp Carassius auratus langsdorfii

Yasuhiro Shibasakia, H Todaa, Isao kobayashib, T Moritomoa, T Nakanishia
Developmental and Comparative Immunology 34 (2010) 1075–1081
http://dx.doi.org:/10.1016/j.dci.2010.05.009

We have previously demonstrated the presence of graft-versus-host reaction (GVHR) in fish employing a model system of clonal triploid ginbuna and tetraploid ginbuna-goldfish hybrids. To elucidate the role of CD8+ T cells in the induction of GVHR, we investigate the kinetics of CD4+ and CD8+ T-cell subsets in GVHR along with the pathological changes associated with GVH disease (GVHD) in ginbuna. GVHR was not induced with a leukocyte fraction lacking CD8+ T cells separated by magnetic cell sorting. Ploidy and immunofluorescence analysis revealed that CD4+ and CD8+  T cells from sensitized donors greatly

increased in the host trunk kidney, constituting more than 80% of total cells 1–2 weeks after donor cell injection, while those from non-sensitized donors constituted less than 50% of cells present. The increase of CD4+ T cells was greater and more rapid than that of CD8+ T cells. The number of donor CD4+ and CD8+ T cells was highest in trunk kidney followed by spleen. Increases in donor CD4+ and CD8+ T cells were also found in liver and PBL, although the percentages were not as high. Pathologic changes similar to those in human and murine acute GVHD were observed in the lymphoid organs as well as target organs such as skin, liver and intestine, including the destruction of cells and tissues and massive leukocyte infiltration. The pathologic changes became more severe with the increase of CD8+ T cells. These results suggest that donor-derived CD8+ T cells play essential roles for the induction of acute GVHR/D in teleosts as in mammals.

Fludarabine and Exposure-Targeted Busulfan Compares Favorably with Busulfan/Cyclophosphamide-Based Regimens in Pediatric Hematopoietic
Cell Transplantation: Maintaining Efficacy with Less Toxicity

I.H. Bartelink, E.M.L. van Reij, C.E. Gerhardt, E.M. van Maarseveen, et al
Biol Blood Marrow Transplant 20 (2014) 345e353
http://dx.doi.org/10.1016/j.bbmt.2013.11.027

Busulfan (Bu) is used as a myeloablative agent in conditioning regimens before allogeneic hematopoietic cell transplantation (allo-HCT). In line with strategies explored in adults, patient outcomes may be optimized by replacing cyclophosphamide (Cy) with or without melphalan (Mel) with fludarabine (Flu). We compared outcomes in 2 consecutive cohorts of HCT recipients with a nonmalignant HCT indication, a myeloid malignancy, or a lymphoid malignancy with a contraindication for total body irradiation (TBI). Between 2009 and 2012, 64 children received Flu + Bu at a target dose of 80-95 mg-h/L, and between 2005 and 2008, 50 children received Bu targeted to 74-80 mg-h/L þ Cy. In the latter group, Mel was added for patients with myeloid malignancy (n = 12). Possible confounding effects of calendar time were studied in 69 patients receiving a myeloablative dose of TBI between 2005 and 2012. Estimated 2-year survival and event-free survival were 82% and 78%, respectively, in the FluBu arm and 78% and 72%, respectively, in the BuCy (Mel) arm (P,  not significant). Compared with the BuCy (Mel) arm, less toxicity was noted in the FluBu arm, with lower rates of acute (noninfectious) lung injury (16% versus 36%; P < .007), veno-occlusive disease (3% versus 28%; P < .003), chronic graft-versus-host disease (9% versus 26%; P < .047), adenovirus infection (3% versus 32%; P < .001), and human herpesvirus 6 infection reactivation (21% versus 44%; P < .005). Furthermore, the median duration of neutropenia was shorter in the FluBu arm (11 days versus 22 days; P < .001), and the patients in this arm required fewer transfusions. Our data indicate that Flu (160 mg/m2) with targeted myeloablative Bu (90 mg-h/L) is less toxic than and equally effective
as BuCy (Mel) in patients with similar indications for allo-HCT.

Fibrotic and Sclerotic Manifestations of Chronic Graft-versus-Host Disease

Carrie L. Kitko, Eric S. White, Kristin Baird
Biol Blood Marrow Transplant 18:S46-S52, 2012
http://dx.doi.org:/10.1016/j.bbmt.2011.10.021

Chronic graft-versus-host disease (cGVHD) is a common cause of morbidity
and mortality following allogeneic stem cell transplantation (HCT), with approximately 50% to 60% of long-term HCT survivors developing one or more manifestations of the disorder. Although acute GVHD is typically limited to skin, liver, and gastrointestinal involvement, virtually every organ is at risk for the development of cGVHD. Although the pathophysiology of cGVHD remains poorly understood, some of the most severe organ manifestations are linked by end-organ fibrosis. In particular, fibrotic cutaneous and bronchiolar changes, resulting in scleroderma-like changes and bronchiolitis obliterans syndrome (BOS), respectively, are two of the most devastating outcomes for these patients. Both sclerotic GVHD (ScGVHD) and BOS have been reported in 5% to 15% of patients with cGVHD.

Many of the manifestations of cGVHD share clinical characteristics seen in nontransplant conditions, including systemic sclerosis or pulmonary fibrosis. Thus, understanding the pathophysiology underlying these related conditions may help identify potential mechanisms and ultimately new therapeutic options for patients with cGVHD.

Tyrosine kinase inhibitors (TKIs) have been shown to inhibit two different profibrotic pathways (transforming growth factor β [TGF-β] and platelet-derived growth factor [PDGF]) in various mouse models of fibrotic disease and offer a possible novel treatment approach for cGVHD patients suffering from severe sclerosis. Likewise, overexpression of TNF-α has been shown to induce fibrogenesis in experimental hepatocellular disease and has been linked with human scleroderma-associated interstitial pulmonary fibrosis and profibrotic responses in human osteoarthritic hip joint fibroblasts. The use of TNF antagonists has been examined in some clinical situations associated with fibrosis, suggesting they may also be of some benefit to patients with cGVHD; however, this must first be prospectively tested.

Table. Proposed Modifications to NIH BOS Clinical Definition

  • Absence of infection (no change)
  • Another cGVHD manifestation in another organ (no change)
  • FEV1 <75% predicted (no change) or >10% decline from pre-HCT value (modification)
  • Signs of Obstruction
  • FEV1/SVC ratio <0.7 (modification), or
  • RV >120% predicted (no change), or
  • RV/TLC >120% (modification), and
  • HRCT with evidence of air trapping (no change)

SVC indicates slow vital capacity; RV, residual volume; TLC, total lung capacity; HRCT, high-resolution computed tomography

Figure (not shown)
Effect of etanercept on survival in post-HCT patients with subacute lung injury. (A) Overall 5-year survival by pulmonary function testing defect. Patients with an obstructive defect (solid line) had a 5-year survival of 67% compared with 44% in those with a restrictive lung defect (dashed line) (P 5 .19). (B) Overall 5-year survival by response to therapy. Patients who responded to etanercept therapy (solid line) had a 5-year survival of 90% compared with 55% in patients who failed to respond (dashed line) (P 5.07). (Figures reprinted with permission, Biol Blood and Marrow Trans).

Extensive, sclerotic skin changes with superficial or deep subcutaneous or fascial involvement are seen in approximately 4% to 13% of patients with cGVHD and can be a life-threatening manifestation. ScGVHD of the skin includes several cutaneous presentations characterized by inflammation and progressive fibrosis of the dermis and subcutaneous tissues. These changes can resemble morphea, systemic sclerosis, or eosinophilic fasciitis and may or may not occur in the setting of concurrent overlying epidermal GVHD. When severe, ScGVHD can result in contractures, severe wasting, and chest wall restriction.

Development of clinical trials for patients with cGVHD is difficult because of the complexity and heterogeneity of disease, variable approaches to treatment, and the lack of standardized assessments of disease. In particular, the study of ScGVHD lacks universally accepted measures of disease burden and response. Investigators have used several measures to assess ScGVHD involvement including body surface area, magnetic resonance imaging, ultrasound, and range-of-motion measurements. Additionally, investigators have tried to apply the Rodnan score, the standardmeasure for skin involvement in scleroderma. Thus far, none of these measures has proven
to be completely reliable in the setting of ScGVHD, and it is likely that multiple measures will need to be integrated into the assessment of ScGVHD.

Imatinib mesylate (Gleevec in the US; Glivec in Europe, Australia, and Latin America, marketed by Novartis) is a TKI that has biological activity against both PDGF and TGF-β signaling pathways. Both cytokines have been implicated in the pathogenesis of several fibrosing diseases, including hepatic, renal, and lung, as well as in scleroderma, a disease that closely resembles ScGVHD. In addition, stimulatory antibodies specific for the PDGF receptor (PDGFR) were identified in a series of 39 patients with extensive cGVHD with higher levels detected in those patients with skin involvement. Similar stimulatory antibodies targeting PDGFR have been reported in patients with scleroderma, suggesting an important therapeutic target for these fibrosing conditions. Imatinib mesylate has particularly potent activity against PDGF and is FDA approved in the United States for the treatment of several disorders associated with aberrant PDGFR signaling. The side effect profile of the drug is well established in non-HCT patients, which is helpful in the setting of a therapy for allogenic HCT patients, many of whom have multiorgan system symptoms and possible dysfunction and who will require ongoing immunosuppressive therapy.

Through the efforts of the Chronic GVHD Consortium, led by Stephanie Lee at the Fred Hutchinson Cancer Research Center, there is a multicenter, ongoing prospective evaluation of the NIH diagnostic and assessment tools. This effort has already resulted in several publications that have further refined essential criteria for cGVHD evaluation, including organ-specific manifestations such as BOS and ScGVHD. Currently, the Consortium is conducting a multicenter prospective clinical trial of fluticasone propionate, azithromycin, and montelukast for the treatment of BOS (ClinicalTrials.gov NCT01307462); a separate trial of imatinib versus rituximab for treatment of ScGVHD is also enrolling subjects (ClinicalTrials.gov NCT01309997).

Although cGVHD remains a significant problem for many long-term survivors of HCT, critical advances in cGVHD research and treatment can be achieved by cooperative group efforts such as those put forth by the Chronic GVHD Consortium and the Clinical Trials Network.

Hematopoietic stem cell transplantation (HSCT): An approach to autoimmunity

Carmen Alaez, Mariana Loyola, Andrea Murguıa, Hilario Flores, et al.
Autoimmunity Reviews 5 (2006) 167– 179
http://dx.doi.org:/10.1016/j.autrev.2005.06.003

HSCT provides the opportunity to replace a damaged tissue. It is the most important treatment for high risk hematologic malignant and nonmalignant disorders. An important challenge in the identification of matched donors/patients is the HLA diversity. The Mexican Bone Marrow Registry (DONORMO) has nowadays N5000 donors. The prevalent alleles are Amerindian, Mediterranean (Semitic and Spanish genes) and African. In theory, it is possible to find 11% of 6/6 A–B–DR low resolution matches for 70% of patients with Mexican ancestry. We contributed with 39 unrelated, cord blood and autologous HSCT for patients with malignant, genetic and autoimmune disorders. Overall disease survival was 50% (2–7 years) depending on the initial diagnosis, conditioning, disease evolution or other factors. Clinical studies using autologous and unrelated HSC are performed on patients with refractory autoimmune diseases producing mixed results: mainly, T1D, RA, MS, SLE. Improvement has been observed in skin damage and quality of life in SLE and systemic sclerosis. Disease stabilization in 2/3 of MS patients. However, in RA and T1D, initial benefits have been followed by eventual relapse. With growing clinical experience and protocol improvement, treatment-related mortality is decreasing. Proof efficacy will be achieved by comparing HSCT with standard therapy in autoimmunity.

Monoclonal Antibody-Mediated Targeting of CD123, IL-3 Receptor α Chain, Eliminates Human Acute Myeloid Leukemic Stem Cells

Liqing Jin, Erwin M. Lee, Hayley S. Ramshaw, Samantha J. Busfield, et al.
Cell: Stem Cell 5, 31–42, July 2, 2009
http://dx.doi.org:/10.1016/j.stem.2009.04.018

Leukemia stem cells (LSCs) initiate and sustain the acute myeloid leukemia (AML) clonal hierarchy and possess biological properties rendering them resistant to conventional chemotherapy. The poor survival of AML patients raises expectations that LSC-targeted therapies might achieve durable remissions. We report that an anti-interleukin-3 (IL-3) receptor α chain (CD123)-neutralizing antibody (7G3) targeted AML-LSCs, impairing homing
to bone marrow (BM) and activating innate immunity of nonobese diabetic/ severe-combined immunodeficient (NOD/SCID) mice. 7G3 treatment profoundly reduced AML-LSC engraftment and improved mouse survival.
Mice with preestablished disease showed reduced AML burden in the BM
and periphery and impaired secondary transplantation upon treatment, establishing that AMLLSCs were directly targeted. 7G3 inhibited IL-3-mediated intracellular signaling of isolated AML CD34+ CD38[1] cells in vitro and reduced their survival. These results provide clear validation for therapeutic monoclonal antibody (mAb) targeting of AML-LSCs and for translation of in vivo preclinical research findings toward a clinical application.

Many Days at Home during Neutropenia after Allogeneic Hematopoietic Stem Cell Transplantation Correlates with Low Incidence of Acute Graft-versus-Host Disease

Olle Ringdén, Mats Remberger, Katarina Holmberg, Charlotta Edeskog, et al.
Biol Blood Marrow Transplant 19 (2013) 314e320
http://dx.doi.org/10.1016/j.bbmt.2012.10.011

Patients are isolated in the hospital during the neutropenic phase after allogeneic hematopoietic stem cell transplantation. We challenged this by allowing patients to be treated at home. A nurse from the unit visited and checked the patient. One hundred forty-six patients treated at home were compared with matched hospital control subjects. Oral intake was intensified from September 2006 and improved (P < .002). We compared 4 groups: home care and control subjects before and after September 2006. The cumulative incidence of acute graft-versus-host disease (GVHD) of grades II to IV was 15% in the “old” home care group, which was significantly lower than that of 32% to 44% in the other groups (P <.03). Transplantation-related mortality, chronic GVHD, and relapse were similar in the groups. The “new” home care patients spent fewer days at home (P < .002). In multivariate analysis, GVHD of grades 0 to I was associated with home care (hazard ratio [HR], 2.46; P <.02) and with days spent at home (HR, .92; P < .005) but not with oral nutrition (HR, .98; P = .13). Five year survival was 61% in the home care group as compared with 49% in the control subjects (P < .07). Home care is safe. Home care and many days spent at home were correlated with a low risk of acute GVHD.

Impact on Outcomes of Human Leukocyte Antigen Matching by Allele-Level Typing in Adults with Acute Myeloid Leukemia Undergoing Umbilical Cord Blood Transplantation

Jaime Sanz, Francisco J. Jaramillo, Dolores Planelles, Pau Montesinos, et al.
Biol Blood Marrow Transplant 20 (2014) 106e110
http://dx.doi.org/10.1016/j.bbmt.2013.10.016

This retrospective study analyzed the impact of directional donor-recipient human leukocyte antigen (HLA) disparity using allele-level typing at HLA-A, -B, -C, and -DRB1 in 79 adults with acute myeloid leukemia (AML) who received single-unit umbilical cord blood (UCB) transplant at a single institution. With extended high resolution HLA typing, the donor-recipient compatibility ranged from 2/8 to 8/8. HLA disparity showed no negative impact on nonrelapse mortality (NRM), graft-versus-host (GVH) disease or engraftment. Considering disparities in the GVH direction, the 5-year cumulative incidence of relapse was 44% and 22% for patients receiving an UCB unit matched > 6/8 and < 6/8, respectively (P <.04). In multivariable analysis, a higher HLA disparity in the GVH direction using extended high-resolution typing (Risk ratio [RR] 2.8; 95% confidence interval [CI], 1.5 to 5.1; P ¼.0009) and first complete remission at time of transplantation (RR 2.1; 95% CI, 1.2 to 3.8; P < .01) were the only variables significantly associated with an improved disease-free survival. In conclusion, we found that in adults with AML undergoing single-unit UCBT, an increased number of HLA disparities at allele-level typing improved disease-free survival by decreasing the relapse rate without a negative effect on NRM.

HLA mismatch direction in cord blood transplantation: impact on outcome and implications for cord blood unit selection
Cladd E. Stevens, C Carrier, C Carpenter, D Sung, and A Scaradavou

Blood. 2011; 118(14):3969-3978
http://dx.doi.org:/10.1182/blood-2010-11-317271

Donor-recipient human leukocyte antigen mismatch level affects the outcome of unrelated cord blood (CB) transplantation. To identify possible “permissive” mismatches, we examined the relationship between  direction of human leukocyte antigen mismatch (“vector”) and transplantation outcomes in 1202 recipients of single CB units from the New York Blood Center National Cord Blood Program treated in United States Centers from 1993-2006. Altogether, 98 donor/patient pairs had only unidirectional mismatches: 58 in the graft-versus-host (GVH) direction only (GVH-O) and 40 in the host-versus-graft or rejection direction only (R-O). Engraftment was faster in patients with GVH-O mismatches compared with those with 1 bidirectional mismatch (hazard ratio [HR] = 1.6, P < .003). In addition, patients with hematologic malignancies given GVH-O grafts had lower transplantation-related mortality (HR = 0.5, P < .062), overall mortality (HR = 0.5, P < .019), and treatment failure (HR = 0.5, P < .016), resulting in outcomes similar to those of matched CB grafts. In contrast, R-O mismatches had slower engraftment, higher graft failure, and higher relapse rates (HR = 2.4, P < .010). Based on our findings, CB search algorithms should be modified to identify unidirectional mismatches. We recommend that transplant centers give priority to GVH-O-mismatched units over other mismatches and avoid selecting R-O mismatches, if possible.

Mutation of the NPM1 gene contributes to the development of donor cell–derived acute myeloid leukemia after unrelated cord blood transplantation
for acute lymphoblastic leukemia

G Rodríguez-Macías, C Martínez-Laperche, J Gayoso, V Noriega, .., Ismael Buño
Human Pathology (2013) 44, 1696–1699
http://dx.doi.org/10.1016/j.humpath.2013.01.001

Donor cell leukemia (DCL) is a rare but severe complication after allogeneic stem cell transplantation. Its true incidence is unknown because of a lack of correct recognition and reporting, although improvements in molecular analysis of donor-host chimerism are contributing to a better diagnosis of this complication. The mechanisms of leukemogenesis are unclear, and multiple factors can contribute to the development of DCL. In recent years, cord blood has emerged as an alternative source of hematopoietic progenitor cells, and at least 12 cases of DCL have been reported after unrelated cord blood transplantation. We report a new case of DCL after unrelated cord blood transplantation in a 44-year-old woman diagnosed as having acute lymphoblastic leukemia with t(1;19) that developed acute myeloid leukemia with normal karyotype and nucleophosmin (NPM1) mutation in donor cells. To our knowledge, this is the first report of NPM1 mutation contributing to DCL development.

Graft-versus-leukemia in the bone marrow
Blood, 23 JAN 2014; 123(4)
http://imagebank.hematology.org.

63-year-old female with relapsed acute myeloid leukemia (AML) after allogeneic stem cell transplantation reached CR2 after re-induction therapy followed by consolidation with donor lymphocyte infusions: 3 x 107/kg and 3 x 108/kg after 1 and 2.5 months, respectively. No signs of graft-versus-host disease were observed at this time. At 5 months follow-up, her blood count deteriorated: hemoglobin: 6.9 mmol/L, thrombocytes: 58 x 109/L and leukocytes: 1.37 x 109/L. Bone marrow aspirate was not evaluable. Bone marrow trephine biopsy showed relapse AML with hypercellularity in the H&E staining (340 objective lens, panel A) and 20% CD341 blast cells without any signs of maturation (panel B). Also, a high number of CD3 positive T cells (panel C) was noted, intermingling with the CD34 positive blasts, both staining positively with CD43 (panel D). Only supportive care was given. However, normalization of the blood count was observed in the following months and she developed graft-versus-host disease of the lung, which was treated with ciclosporin and prednisone. A bone marrow aspirate performed 3 months after relapse showed a third remission with 0.8% myeloid blasts. In retrospect, one could therefore consider the picture of the bone marrow trephine biopsy at the second relapse as graft-versus-leukemia in the bone marrow.

GVL- panel A

GVL- panel A

GVL - panel B

GVL – panel B

GVL - panel C

GVL – panel C

GVL - panel D

Long-Term Outcomes of Alemtuzumab-Based Reduced-Intensity Conditioned Hematopoietic Stem Cell Transplantation for Myelodysplastic Syndrome and Acute Myelogenous Leukemia Secondary to Myelodysplastic Syndrome

Victoria T. Potter, Pramila Krishnamurthy, Linda D. Barber, ZiYi Lim, et al.
Biol Blood Marrow Transplant 20 (2014) 111e117
http://dx.doi.org/10.1016/j.bbmt.2013.10.021

Allogeneic hematopoietic stem cell transplantation (HSCT) with reduced-intensity conditioning (RIC) offers a potential cure for patients with myelodysplastic syndrome (MDS) who are ineligible for standard-intensity regimens. Previously published data from our institution suggest excellent outcomes at 1 yr using a uniform fludarabine, busulfan, and alemtuzumab-based regimen. Here we report long-term follow-up of 192 patients with MDS and acute myelogenous leukemia (AML) secondary to MDS (MDS-AML) transplanted with this protocol, using sibling (n = 45) or matched unrelated (n = 147) donors. The median age of the cohort was 57 yr (range, 21 to 72 yr), and median follow-up was 4.5 yr (range, 0.1 to 10.6 yr). The 5-yr overall survival (OS), event-free survival, and nonrelapse mortality were 44%, 33%, and 26% respectively. The incidence of de novo chronic graft-versus-host disease (GVHD) was low at 19%, illustrating the efficacy of alemtuzumab for GVHD prophylaxis. Conversely, the 5-yr relapse rate was 51%. For younger patients (age <50 yr), the 5-yr OS and relapse rates were 58% and 39%, respectively. On multivariate analysis, advanced age predicted significantly worse outcomes, with patients age >60 yr having a 5-yr OS of 15% and relapse rate of 66%. Patients receiving preemptive donor lymphocyte infusions had an impressive 5-yr OS of 67%, suggesting that this protocol may lend itself to the incorporation of immunotherapeutic strategies. Overall, these data demonstrate good 5-yr OS for patients with MDS and MDS-AML undergoing alemtuzumab-based RIC-HSCT. The low rate of chronic GVHD is encouraging, and comparative studies with other RIC protocols are warranted.

Natural killer cell activity influences outcome after T cell depleted stem cell transplantation from matched unrelated and haploidentical donors

Peter Lang, Matthias Pfeiffer,  Heiko-Manuel Teltschik, Patrick Schlegel, et al.
Best Practice & Research Clinical Haematology 24 (2011) 403–411
http://dx.doi.org:/10.1016/j.beha.2011.04.009

Lytic activity and recovery of natural killer (NK) cells was monitored in pediatric patients with leukemias (ALL, AML, CML, JMML) and myelodysplastic syndromes after transplantation of T cell depleted stem cells from matched unrelated (n = 18) and mismatched related (haploidentical, n = 29) donors. CD34+ selection with magnetic microbeads resulted in 8 x 103/kg residual T cells. No post-transplant immune suppression was given. NK cells recovered rapidly after transplantation (300 CD56+/mL at day 30, median), whereas T cell recovery was delayed (median: 12 CD3+/mL at day 90). NK activity was measured as specific lysis of K 562 targets several times (mean: 3 assays per patient). Four temporal patterns of lytic activity could be differentiated: consistently low, consistently high, decreasing and increasing activity. Patients with consistently high or increasing activity had significantly lower relapse probability than patients with consistently low or decreasing levels (0.18 vs 0.73 at 2 years, p < 0.05). The subgroup of patients with ALL showed similar results (0.75 vs 0.14 at 2 years, p < 0.05). Speed of T cell recovery had no influence. These data suggest that both achieving and maintaining a high level of NK activity may contribute to prevent relapse. Since NK activity could be markedly increased by in vitro stimulation with Interleukin 2 (IL-2), in vivo administration should be considered.

Graft-versus-host disease: Pathogenesis and clinical manifestations of graft-versus-host disease

Sharon R. Hymes, Amin M. Alousi,  and Edward W. Cowen
J Am Acad Dermatol  2012; 66: 515.e1-18.

  • Graft-versus-host disease is the primary cause of morbidity and nonerelapse related mortality in patients who undergo allogeneic hematopoietic cell transplantation.
  • Acute graft-versus-host disease manifests as a skin exanthem, liver dysfunction, and gastrointestinal involvement.
  • Chronic graft-versus-host disease of the skin is remarkably variable in its clinical presentation.
  • Chronic graft-versus-host disease is a multisystem disorder that may affect nearly any organ; the most common sites are the skin, oral mucosa, and eyes.

Key points

  • Allogeneic transplantation is in widespread use for hematologic malignancies, but is also increasingly used for marrow failure syndromes, immunodeficiencies, and other life-threatening conditions
  • Graft-versus-host disease is the primary cause of morbidity and nonerelapse related mortality after allogeneic hematopoietic cell transplantation
  • Minimizing graft-versus-host disease without losing the graft-versus-tumor effect is an area of active research
  • The skin is the most common organ affected in patients with graft-versus-host disease

Outcomes of Thalassemia Patients Undergoing Hematopoietic Stem Cell Transplantation by Using a Standard Myeloablative versus a Novel Reduced-Toxicity Conditioning Regimen According to a New Risk Stratification

Usanarat Anurathapan, S Pakakasama, P Mekjaruskul, N Sirachainan, et al.
Biol Blood Marrow Transplant 20 (2014) 2056e2075
http://dx.doi.org/10.1016/j.bbmt.2014.07.016

Improving outcomes among class 3 thalassemia patients receiving allogeneic hematopoietic stem cell transplantations (HSCT) remains a challenge. Before HSCT, patients who were > 7 years old and had a liver size > 5 cm constitute what the Center for International Blood and Marrow Transplant Research defined as a very high risk subset of a conventional high-risk class 3 group (here referred to as class 3 HR). We performed HSCT in 98 patients with related and unrelated donor stem cells. Seventy-six of the patients with age < 10 years received the more conventional myeloablative conditioning (MAC) regimen (cyclophos-phamide, busulfan,  + fludarabine); the remaining 22 patients with age > 10 years and hepatomegaly (class 3 HR), and in several instances additional comorbidity problems, underwent HSCT with a novel reduced-toxicity conditioning (RTC) regimen (fludarabine and busulfan). We then compared the outcomes between these 2 groups (MAC versus RTC). Event-free survival (86% versus 90%) and overall survival (95% versus 90%) were not significantly different between the respective groups; however, there was a higher incidence of serious treatment-related complications in the MAC group, and although we experienced 6 graft failures in the MAC group (8%), there were none in the RTC group. Based on these results, we suggest that (1) class 3HRthalassemia patients can safely receive HSCT with our novel RTC regimen and achieve the same excellent outcome as low/standard-risk thalassemia patients who received the standard MAC regimen, and further, (2) that this novel RTC approach should be tested in the low/standard-risk patient population.

Pharmacological Immunosuppression Reduces But Does Not Eliminate the Need for Total-Body Irradiation in Nonmyeloablative Conditioning Regimens for Hematopoietic Cell Transplantation

Marco Mielcarek, Beverly Torok-Storb, Rainer Storb
Biol Blood Marrow Transplant 17: 1255-1260 (2011)
http://dx.doi.org:/10.1016/j.bbmt.2011.01.003

In the dog leukocyte antigen (DLA)-identical hematopoietic cell transplantation (HCT) model, stable marrow engraftment can be achieved with total-body irradiation (TBI) of 200 cGy when used in combination with postgrafting immunosuppression. The TBI dose can be reduced to 100 cGy without compromising engraftment rates if granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (G-PBMC) are infused with the marrow. T cell-depleting the G-PBMC product abrogates this effect. These results were interpreted to suggest that the additional T cells provided with G-PBMC facilitated engraftment by overcoming host resistance.We therefore hypothesized that the TBI dose may be further reduced to 50 cGy by augmenting immunosupression either by (1) tolerizing or killing recipient T cells, or (2) enhancing the graft-versus-host (GVH) activity of donor T cells. To test the first hypothesis, recipient T cells were activated before HCT by repetitive donor-specific PBMC infusions followed by administration of methotrexate (MTX) (n 5 5), CTLA4-Ig (n = 4), denileukin diftitox (Ontak; n = 4), CTLA4-Ig 1 MTX (n = 8), or 5c8 antibody (anti-CD154) 1 MTX (n = 3). To test the second hypothesis, recipient dendritic cells were expanded in vivo by infusion of Flt3 ligand given either pre-HCT (n = 4) or pre- and post-HCT (n = 5) to augment GVH reactions. Although all dogs showed initial allogeneic engraftment, sustained engraftment was seen in only 6 of 42 dogs (14% of all dogs treated in 9 experimental groups). Hence, unless more innovative pharmacotherapy can be developed that more forcefully shifts the immunologic balance in favor of the donor, noncytotoxic immunosuppressive drug therapy as the sole component of HCT preparative regimens may not suffice to ensure sustained engraftment.

Pretransplant Immunosuppression followed by Reduced-Toxicity Conditioning and Stem Cell Transplantation in High-Risk Thalassemia: A Safe Approach to Disease Control

Usanarat Anurathapan, S Pakakasama, P Rujkijyanont, N Sirachainan, et al.
Biol Blood Marrow Transplant 19 (2013) 1254e1270
http://dx.doi.org/10.1016/j.bbmt.2013.04.023

Patients with class 3 thalassemia with high-risk features for adverse events after high-dose chemotherapy with hematopoietic stem cell transplantation (HSCT) are difficult to treat, tending to either suffer serious toxicity or fail to establish stable graft function. We performed HSCT in 18 such patients age 7 years and hepatomegaly using a novel approach with pretransplant immunosuppression followed by a myeloablative reduced-toxicity conditioning regimen (fludarabine and i.v. busulfan [Flu-IV Bu]) and then HSCT. The median patient age was 14 years (range, 10 to 18 years). Before the Flu-IV Bu þ antithymocyte globulin conditioning regimen, all patients received 1 to 2 cycles of pretransplant immunosuppression with fludarabine and dexamethasone. Thirteen patients received a related donor graft, and 5 received an unrelated donor graft. An initial prompt engraftment of donor cells with full donor chimerism was observed in all 18 patients, but 2 patients developed secondary mixed chimerism that necessitated withdrawal of immunosuppression to achieve full donor chimerism. Two patients (11%) had acute grade III-IV graft-versus-host disease, and 5 patients had limited chronic graft-versus-host disease. The only treatment-related mortality was from infection, and with a median follow-up of 42 months (range, 4 to 75), the 5-year overall survival and thalassemia-free survival were 89%. We conclude that this novel sequential immunoablative pretransplant-ation conditioning program is safe and effective for patients with high-risk class 3 thalassemia exhibiting additional comorbidities.

Profiling antibodies to class II HLA in transplant patient sera

Curtis McMurtrey, D Lowe, R Buchli, S Daga, D Royer, A Humphrey, et al.
Human Immunology 75 (2014) 261–270
http://dx.doi.org/10.1016/j.humimm.2013.11.015

Immunizing events including pregnancy, transfusions, and transplantation promote strong alloantibody responses to HLA. Such alloantibodies to HLA preclude organ transplantation, foster hyperacute rejection, and contribute to chronic transplant failure. Diagnostic antibody-screening assays detect alloreactive antibodies, yet key attributes including antibody concentration and isotype remain largely unexplored. The goal here was to provide a detailed profile of allogeneic antibodies to class II HLA. Methodologically, alloantibodies were purified from sensitized patient sera using an HLA-DR11 immunoaffinity column and subsequently categorized. Antibodies to DR11 were found to fix complement, exist at a median serum concentration of 2.3 lg/mL, consist of all isotypes, and isotypes IgG2, IgM, and IgE were elevated. Because multimeric isotypes can confound diagnostic determinations of antibody concentration, IgM and IgA isotypes were removed and DR11-IgG tested alone. Despite removal of multimeric isotypes, patient-to patient antibody concentra-tions did not correlate with MFI values. In conclusion, allogeneic antibody responses to DR11 are comprised of all antibody isotypes at differing proportions, these combined isotypes fix complement at nominal serum concentrations, and enhancements other than the removal of IgM and IgA multimeric isotypes may be required if MFI is to be used as a means of determining anti-HLA serum antibody concentrations in diagnostic clinical assays.

Reduced-intensity conditioning and HLA-matched hemopoietic stem-cell transplantation in patients with chronic granulomatous disease: a prospective multicenter study

Tayfun Güngör, P Teira, M Slatter, G Stussi, P Stepensky, D Moshous, et al.
Lancet 2014; 383: 436–48
http://dx.doi.org/10.1016/S0140-6736(13)62069-3

Background In chronic granulomatous disease allogeneic hemopoietic stem-cell transplantation (HSCT) in adolescents and young adults and patients with high-risk disease is complicated by graft-failure, graft-versus-host disease (GVHD), and transplant-related mortality. We examined the effect of a reduced-intensity conditioning regimen designed to enhance myeloid engraftment and reduce organ toxicity in these patients.       Methods This prospective study was done at 16 centers in ten countries worldwide. Patients aged 0–40 years with chronic granulomatous disease were assessed and enrolled at the discretion of individual centers. Reduced-intensity conditioning consisted of high-dose fludarabine (30 mg/m² [infants <9 kg 1∙2 mg/kg]; one dose per day on days –8 to –3), serotherapy (anti-thymocyte globulin [10 mg/kg, one dose per day on days –4 to –1; or thymoglobulin 2·5 mg/kg, one dose per day on days –5 to –3]; or low-dose alemtuzumab [<1 mg/kg on days –8 to –6]), and low-dose (50–72% of myeloablative dose) or targeted busulfan administration (recommended cumulative area under the curve: 45–65 mg/L × h). Busulfan was administered mainly intravenously and exceptionally orally from days –5 to –3. Intravenous busulfan was dosed according to weight-based recommendations and was administered in most centers (ten) twice daily over 4 h. Unmanipulated bone marrow or peripheral blood stem cells from HLA-matched related donors or HLA-9/10 or HLA-10/10 matched unrelated-donors were infused. The primary endpoints were overall survival and event-free survival (EFS), probabilities of overall survival and EFS at 2 years, incidence of acute and chronic GVHD, achievement of at least 90% myeloid donor chimerism, and incidence of graft failure after at least 6 months of follow-up. Findings 56 patients (median age 12∙7 years; IQR 6·8–17·3) with chronic granulomatous disease were enrolled from June 15, 2003, to Dec 15, 2012. 42 patients (75%) had high-risk features (ie, intractable infections and autoinflammation), 25 (45%) were adolescents and young adults (age 14–39 years). 21 HLA-matched related-donor and 35 HLA-matched unrelated-donor transplants were done. Median time to engraftment was 19 days (IQR 16–22) for neutrophils and 21 days (IQR 16–25) for platelets. At median follow-up of 21 months (IQR 13–35) overall survival was 93% (52 of 56) and EFS was 89% (50 of 56). The 2-year probability of overall survival was 96% (95% CI 86∙46–99∙09) and of EFS was 91% (79∙78–96∙17). Graft-failure occurred in 5% (three of 56) of patients. The cumulative incidence of acute GVHD of grade III–IV was 4% (two of 56) and of chronic graft-versus-host disease was 7% (four of 56). Stable (≥90%) myeloid donor chimerism was documented in 52 (93%) surviving patients. Interpretation This reduced-intensity conditioning regimen is safe and efficacious in high-risk patients with chronic granulomatous disease.

Refinement of the Definition of Permissible HLA-DPB1 Mismatches with Predicted Indirectly ReCognizable HLA-DPB1 Epitopes

Kirsten A. Thus, MTA Ruizendaal, TA de Hoop, Eric Borst, et al.
Biol Blood Marrow Transplant 20 (2014) 1705e1710
http://dx.doi.org/10.1016/j.bbmt.2014.06.026

Hematopoietic stem cell transplantation with HLA-DPB1emismatched donors leads to an increased risk of acute graft-versus-host disease (GVHD). Studies have indicated a prognostic value for classifying HLA-DPB1 mismatches based on T cell epitope (TCE) groups. The aim of this study was to determine the contribution of indirect recognition of HLA-DPe derived epitopes, as determined with the Predicted Indirectly ReCognizable HLA Epitopes (PIRCHE) method. We therefore conducted a retrospective single-center analysis on 80 patients transplanted with a 10/10 matched unrelated donor that was HLA-DPB1 mismatched. HLADPB1 mismatches that were classified as GVH nonpermissive by the TCE algorithm correlated to higher numbers of HLA class I as well as HLA class II presented PIRCHE (PIRCHE-I and -II) compared with permissive or host-versus-graft nonpermissive mismatches. Patients with acute GVHD grades II to IV presented significantly higher numbers of PIRCHE-I compared with patients without acute GVHD (P < .05). Patients were divided into 2 groups based on the presence or absence of PIRCHE. Patients with PIRCHE-I or -II have an increased hazard of acute GVHD when compared with patients without PIRCHE-I or -II (hazard ratio [HR], 3.19; 95% confidence interval [CI], 1.10 to 9.19; P <.05; and HR, 4.07; 95% CI, .97 to 17.19; P < .06, respectively). Patients classified as having an HLA-DPB1 permissive mismatch by the TCE model had an increased risk of acute GVHD when comparing presence of PIRCHE-I with absence of PIRCHE-I (HR, 2.96; 95% CI, .84 to 10.39; P < .09). We therefore conclude that the data presented in this study describe an attractive and feasible possibility to better select permissible HLA-DPB1 mismatches by including both a direct and an indirect recognition model.

Treosulfan-Thiotepa-FludarabineeBased Conditioning Regimen for
Allogeneic Transplantation in Patients with Thalassemia Major: A
Single-Center Experience from North India

Dharma Choudhary, SK Sharma, N Gupta,…, Satyendra Katewa
Biol Blood Marrow Transplant 19 (2013) 492e503
http://dx.doi.org/10.1016/j.bbmt.2012.11.007

Hematopoietic stem cell transplantation (HSCT) is the definite treatment
for patients with thalassemia major. A busulfan (Bu) and cyclophosphamide
(Cy)ebased regimen has been the standard myeloablative chemotherapy,
but it is associated with higher treatment-related toxicity, particularly in
patients classified as high risk by the Pesaro criteria. Treosulfan-based
conditioning regimens have been found to be equally effective and less
toxic. Consequently, we analyzed the safety and efficacy of treosulfan/
thiotepa/fludarabine (treo/thio/flu)-based conditioning regimens for
allogeneic HSCT in patients with thalassemia major between February
2010 and September 2012. We compared those results retrospectively
with results in patients who underwent previous HSCT with a Bu/Cy/
antithymocyte globulin (ATG)ebased conditioning regimen. A treo/thio/
flu-based conditioning regimen was used in 28 consecutive patients with
thalassemia major. The median patient age was 9.7 years (range, 2-18
years), and the mean CD34+ stem cell dose was 6.18 x 106/kg. Neutrophil
and platelet engraftment occurred at a median of 15 days (range, 12-23
days) and 21 days (range, 14-34 days), respectively. Three patients
developed veno-occlusive disease, 4 patients developed acute graft
versus-host disease (GVHD), and 2 patients had chronic GVHD. Treatment-
related mortality (TRM) was 21.4%. Two patients experienced secondary
graft rejection. We compared these results with results in patients who
underwent previous HSCT using a Bu/Cy/ATG-based conditioning regimen.
Twelve patients were treated with this protocol, at a median age of 7.2
years (range, 2-11 years). One patient had moderate veno-occlusive disease,
2 patients developed acute GVHD, 2 patients had chronic GVHD, and 2
patients experienced graft rejection. There was no TRM in this group. We
found no significant differences between the 2 groups (treo/thio/flu vs Bu/
Cy/ATG) in terms of the incidence of acute GVHD, chronic GVHD, TRM,
and graft failure, although a trend toward higher TRM was seen with the
treo/thio/flu regimen.

Graft-versus-Host Disease
James L.M. Ferrara, John E. Levine, Pavan Reddy, and Ernst Holler
Lancet. 2009 May 2; 373(9674): 1550–1561
http:dx.doi.org:/10.1016/S0140-6736(09)60237-3

The number of allogeneic hematopoietic cell transplantations (HCT)
continues to increase with more than 25,000 allogeneic transplantations
performed annually. The graft-versus leukemia/ tumor (GVL) effect during
allogeneic HCT effectively eradicates many hematological malignancies.
The development of novel strategies that use donor leukocyte infusions,
non-myeloablative conditioning and umbilical cord blood (UCB)
transplantation have helped expand the indications for allogeneic HCT
over the last several years, especially among older patients. Improvements
in infectious prophylaxis, immunosuppressive medications, supportive care
and DNA-based tissue typing have also contributed to improved outcomes
after allogeneic HCT. Yet the major complication of allogeneic HCT, graft-
versus-host disease (GVHD), remains lethal and limits the use of this
important therapy. Given current trends, the number of transplants from
unrelated donors is expected to double within the next five years,
significantly increasing the population of patients with GVHD. In this
seminar we review advances made in identifying the genetic risk
factors and pathophysiology of this major HCT complication, as well
as its prevention, diagnosis and treatment.

Non-HLA Genetics—Despite HLA identity between a patient and donor,
approximately 40% of patients receiving HLA-identical grafts develop
acute GVHD due to genetic differences that lie outside the HLA loci,
or “minor” histocompatibility antigens (HA). Some minor HAs, such as HY
and HA-3, are expressed on all tissues and are targets for both GVHD
and GVL. Other minor HAs, such as HA-1 and HA-2, are expressed most
abundantly on hematopoietic cells (including leukemic cells) and may
therefore induce a greater GVL effect with less GVHD. Polymorphisms
in both donors and recipients for cytokines that are involved in the
classical `cytokine storm’ of GVHD have been implicated as risk factors
for GVHD. Tumor Necrosis Factor (TNF)-α, Interleukin 10 (IL-10),
Interferon-γ (IFNγ) variants have correlated with GVHD in some, but
not all, studies. Genetic polymorphisms of proteins involved in innate
immunity, such as nucleotide oligomerization domain 2 and Keratin 18
receptors, have also been associated with GVHD.

Future strategies to identify the best possible transplant donor will
probably incorporate both HLA and non-HLA genetic factors. Skin is most
commonly affected and is usually the first organ involved, often coinciding
with engraftment of donor cells. The characteristic maculopapular rash is
pruritic and can spread throughout the body, sparing the scalp. In severe
cases the skin may blister and ulcerate. Apoptosis at the base of epidermal
rete pegs is a characteristic pathologic finding. Other features include
dyskeratosis, exocytosis of lymphocytes, satellite lymphocytes adjacent
to dyskeratotic epidermal keratinocytes, and a perivascular lymphocytic
infiltration in the dermis.

Gastrointestinal tract involvement of acute GVHD usually presents as
diarrhea but may also include vomiting, anorexia, and/or abdominal pain
when severe. The diarrhea of GVHD is secretory and often voluminous
(greater than two liters per day). Bleeding, which carries a poor prognosis,
occurs as a result of mucosal ulceration but patchy involvement of the
mucosa often leads to a normal appearance on endoscopy.

The incidence of the severity of acute GVHD is determined by the extent
of involvement of  three principal target organs. The overall grades are
classified as I (mild), II (moderate), III (severe) and IV (very severe). Severe
GVHD carries a poor prognosis, with 25% long term survival for grade III and
5% for grade IV. The incidence of acute GVHD is directly related to the
degree of mismatch between HLA proteins and ranges from 35-45% in
recipients of full matched sibling donor grafts to 60-80% in recipients of
one-antigen HLA mismatched unrelated donor grafts. The same degree
of mismatch causes less GVHD using UCB grafts and incidence of acute
GVHD is lower following the transplant of partially matched UCB units
and ranges from 35-65%.

Two important principles are important to consider regarding the
pathophysiology of acute GVHD. First, acute GVHD reflects exaggerated
but normal inflammatory mechanisms mediated by donor lymphocytes infused
into the recipient where they function appropriately, given the foreign
environment they encounter. Second, the recipient tissues that stimulate
donor lymphocytes have usually been damaged by underlying disease,
prior infections, and the transplant conditioning regimen. As
a result, these tissues produce molecules (sometimes referred to as
“danger” signals) that promote the activation and proliferation of donor
immune cells.  Based largely on experimental models, the development
of acute GVHD can be conceptualized in three sequential steps or phases:
(1) activation of the APCs; (2) donor T cell activation, proliferation,
differentiation and migration; and (3) target tissue destruction.

Alemtuzumab is a monoclonal antibody that binds CD52, a protein
expressed on a broad spectrum of leukocytes including lymphocytes,
monocytes, and dendritic cells. Its use in GVHD prophylaxis in a
Phase II trial decreased the incidence of acute and chronic GVHD
following reduced intensity transplant.98 In two prospective studies,
patients who received alemtuzumab rather than methotrexate showed
significantly lower rates of acute and chronic GVHD, but experienced
more infectious complications and higher rates of relapse, so that there
was no overall survival benefit. Alemtuzumab may also contribute to
graft failure when used with minimal intensity conditioning regimens.

An alternative strategy to TCD attempted to induce anergy in donor
T cells by ex vivo antibody blockade of co-stimulatory pathways prior
to transplantation. A small study using this approach in haploidentical
HCT recipients was quite encouraging, but has not yet been replicated.
Thus the focus of most prevention strategies remains  pharmacological
manipulation of T cells after transplant.

Administration of anti-T cell antibodies in vivo as GVHD prophylaxis
has also been extensively tested. The best studied drugs are anti-
thymocyte globulin (ATG) or antilymphocyte globulin (ALG) preparations.
These sera, which have high titers of polyclonal antibodies, are made
by immunizing animals (horses or rabbits) to thymocytes or lymphocytes,
respectively. A complicating factor in determining the role of these
polyclonal sera in transplantation is the observation that even different
brands of the same class of sera exert different biologic effects. However,
the side effects of ATG/ALG infusions are common across different
preparations and include fever, chills, headache, thrombocytopenia
(from cross-reactivity to platelets), and, infrequently, anaphylaxis. In
retrospective studies, rabbit ATG reduced the incidence of GVHD in
related donor HSCT recipients without appearing to improve survival.
In recipients of unrelated donor HSCT, addition of ALG to standard
GVHD prophylaxis effectively prevented severe GVHD, but did not
result in improved survival because of increased infections. In a long
term follow-up study, however, pretransplant ATG provided significant
protection against extensive chronic GVHD and chronic lung dysfunction.

As allogeneic transplantation becomes an increasingly attractive therapeutic
option, the need for novel approaches to GVHD has accelerated. The
number of patients receiving transplants from unrelated donors is
expected to double in the next five years, significantly increasing
the population of patients with GVHD. The advent of RIC regimens
has reduced transplant-related mortality and lengthened the period
during which acute GVHD may develop (many new cases present up
to day 200) and the need for close monitoring of patients in this period
has increased. Patients have often returned to the care of their primary
hematologists by this time, increasing the need for these physicians to
collaborate with transplant specialists in the management of GVHD and
its complications.

Identification of biomarkers for GVHD with diagnostic (and possibly
prognostic) significance may eventually make the treatment of GVHD
preemptive rather than prophylactic. The use of cellular component therapy,
such as regulatory T cells that have been expanded ex vivo. will also
enter clinical trials in the near future, but the extensive infrastructure
required for such cellular approaches will likely limit their use initially.

Immunomodulatory Effects of Palifermin (Recombinant Human
Keratinocyte Growth Factor) in 
an SLE-Like Model of Chronic
Graft-Versus-Host Disease

C. A. Ellison, Y. V. Lissitsyn, I. Gheorghiu & J. G. Gartner
Scandinavian Journal of Immunology 2011; 75, 69–76
http://dx.doi.org:/10.1111/j.1365-3083.2011.02628.x

Keratinocyte growth factor (KGF) promotes epithelial cell proliferation
and survival. Recombinant human KGF, also known as palifermin, protects
epithelial cells from injury induced by chemicals, irradiation and acute murine
graft versus-host disease (GVHD). Findings from our studies and others
have shown that palifermin also has immunomodulatory properties. In a
model of acute GVHD, we showed that it shifts the immune response
from one in which Th1 cytokines dominate to mixed Th1 and Th2 cytokine
profile. Using the DBA⁄ 2 fi (C57BL ⁄ 6 · DBA⁄ 2)F1-hybrid model of chronic,
systemic lupus erythematosus-like GVHD, we showed that palifermin
treatment is associated with higher levels of Th2 cytokines, the production
of anti-nuclear antibodies, cryoglobulinemia and the development of more
severe pathological changes in the kidney. The aim of our current study
was to gain a better understanding of the immunobiology of KGF by
further characterizing the palifermin-mediated effects in this model of
chronic GVHD. Because the pathological changes we observed resemble
those seen in thymic stromal lymphopoietin (TSLP) transgenic mice, we
had originally hypothesized that palifermin might augment TSLP levels.
Surprisingly, we did not observe an increase in thymic

TSLP mRNA expression in palifermin-treated recipients. We did, however,
observe some differences in the percentages of CD4+CD25+Foxp3+
regulatory T cells in the spleen at some time points in palifermin-treated
recipients. Most importantly, we found that TGFβ levels were higher in
palifermin-treated recipients early in the GVH reaction, raising the
possibility that KGF might indirectly induce the development of fibrosis
and glomerulonephritis through a pathway involving TGFβ.

Keratinocyte growth factor (KGF) is an epithelial cell growth factor that is
produced by both mesenchymal cells and intraepithelial cdT cells. It is
also known as fibroblast growth factor 7. Its receptor, (KGFR⁄FGF7R), an
alternatively spliced form of FGFR2 ⁄ bek, is found on epithelial cells in
the intestine, mammary glands, ovaries and urinary tract, and on
hepatocytes, keratinocytes and alveolar type II cells. Previously, it
was shown that recombinant human KGF, also known as palifermin,
can protect the lung, bladder or intestine from chemical- or irradiation-
induced injury. This has been attributed to the ability of KGF to reduce
oxidative damage and enhance DNA repair.

Our own studies have provided a better understanding of the immuno-
biological properties of KGF in pathologically distinct models of systemic
disease driven by intense immunological and inflammatory responses.
The acute GVHD that develops in the C57BL ⁄ 6 fi (C57BL ⁄ 6 · DBA⁄ 2)F1-
hybrid model is characterized by the activation of alloreactive donor T cells,
the production of Th1 cytokines and tissue injury in the skin, gastrointestinal
tract, liver, thymus and lung, where epithelia are present. Injury to the
intestinal mucosa permits the translocation of endotoxin into the system,
which, if untreated, leads to the development of endotoxemic shock. We
showed that palifermin treatment protects recipients from epithelial
cell injury, endotoxemia and morbidity in GVH mice. Palifermin also
shifts the immune response away from one that is predominated by Th1
cytokines towards a profile of mixed Th1 and Th2 cytokines, with a
preponderance of Th2 cytokines. The DBA⁄ 2 fi (C57BL ⁄ 6 · DBA⁄ 2)F1-
hybrid model of chronic GVHD is characterized by pathological changes
resembling those seen in systemic lupus erythematosus (SLE). Using this
model, we showed that palifermin treatment augments the production of Th2
cytokines such as IL-4, IL-5 and IL-13 and obviates IFN-c production. Both
untreated and palifermin-treated recipients developed pathological changes
in the kidney, but these changes were more severe in palifermin-treated
recipients. Some of the changes that developed in the palifermin-treated
recipients resemble those seen in thymic stromal lymphopoietin (TSLP)
transgenic mice. These similarities include the presence of ANA in the
sera, the development of cryoglobulinemia and the development of
glomerulonephritis featuring the deposition of immune complexes
consisting of IgG, IgA, IgM and C3 in the mesangium and the glomerular
capillaries. This led us to hypothesize that treating the recipient mice with
palifermin might induce TSLP expression in this model.

In this study, we were interested in determining whether palifermin
treatment was indeed associated with increased TSLP expression.
We were also interested in knowing whether palifermin treatment
changes the percentage of CD4+CD25+FoxP3+ cells in the spleen,
because palifermin treatment has been associated with increased
percentages of CD4+CD25+FoxP3+ cells in other studies including
our own. Lastly, we wished to study the effect of palifermin treatment
on TGFb levels, because this cytokine is known to play a pivotal role
in the development of glomerulonephritis.

We studied the histopathological changes to confirm that the pathological
changes seen in the kidney in this study were the same as those reported
by us previously.We examined kidney sections from both untreated and
palifermin-treated recipients. In these experiments, we were able to
reproduce findings from an earlier study that showed that palifermin-
treated recipients mice in this model of chronic GVHD develop a severe,
extracapillary proliferative glomerular nephritis characterized by epithelial
crescents and hyaline thrombi. These changes were associated with higher
levels of protein in the urine and the development of ascites, presumably
related to the development of nephrotic syndrome, as a consequence
of glomerular injury.

Pathological changes in the kidney

Pathological changes in the kidney. (A) shows a section from a BDF1-hybrid control
mouse that did not receive a graft. (B) shows increased epithelial cellularity within a
glomerulus from an untreated recipient with chronic graft-versus-host disease, on
day 50. No crescents were observed in sections from this group of recipients.
(C and D) show examples of pathological changes observed in kidneys from
palifermin-treated recipients on day 50. Arrows indicate examples of crescentic
glomerulonephritis and the development of protein casts within tubular lumena.
(E and F) show examples of the hyaline thrombi (arrows) seen in the glomeruli
in kidney sections from palifermin-treated recipients on day 50. All sections
were stained with haematoxylin and eosin except for that shown in (F), which
was stained with Masson Trichrome. The concentration of protein measured in
the urine is shown in the lower left corner of each photomicrograph. Original
magnification: ·200 (B–E) and ·400 (A and F).

TGFβ is a highly pleiotropic cytokine with three isoforms, TGFβ1, TGFβ2 and
TGFβ3 . Nearly, all cells have receptors for at least one of these isoforms,
but cells of the immune system primarily express TGFβ1. This cytokine
was implicated in the development of experimental glomerulonephritis in
experiments in which rats were treated with antiserum directed against
TGFβ1. The ability of palifermin to induce TGFβ release and reverse
limited airflow was demonstrated in a mouse model of emphysema. The
authors further showed that palifermin induced the release of TGFβ1
from primary cultures of mouse alveolar type 2 cells. Our results show
that palifermin treatment is associated with a rise in splenic TGFβ levels
during the first month of the GVH reaction. It is possible that by inducing
TGFβ production shortly after transplantation, palifermin treatment is able
to promote the development of the severe, crescentic glomerulonephritis
that we observed at later time points. As such, our findings raise the
possibility that endogenous KGF might play a role in the development
of glomerulonephritis and ⁄ or other autoimmune phenomena associated
with chronic GVHD and ⁄ or SLE.

T cells, murine chronic graft-versus-host disease and autoimmunity

Robert A. Eisenberg, Charles S. Via
Journal of Autoimmunity 39 (2012) 240e247
http://dx.doi.org:/10.1016/j.jaut.2012.05.017

The chronic graft-versus-host disease (cGVHD) in mice is characterized by
the production of autoantibodies and immunopathology characteristic of
systemic lupus erythematosus (lupus). The basic pathogenesis involves
the cognate recognition of foreign MHC class II of host B cells by alloreactive
CD4 T cells from the donor. CD4 T cells of the host are also necessary for
the full maturation of host B cells before the transfer of donor T cells.
CD8 T cells play critical roles as well. Donor CD8 T cells that are highly
cytotoxic can ablate or prevent the lupus syndrome, in part by killing
recipient B cells. Host CD8 T cells can reciprocally downregulate donor
CD8 T cells, and thus prevent them from suppressing the autoimmune
process. Thus, when the donor inoculum contains both CD4 T cells and
CD8 T cells, the resultant syndrome depends on the balance of activities
of these various cell populations. For example, in one cGVHD model
(DBA/2 (C57BL/6xDBA/2)F1, the disease is more severe in females, as
it is in several of the spontaneous mouse models of lupus, as well as in
human disease. The mechanism of this female skewing of disease
appears to depend on the relative inability of CD8 cells of the female host
to downregulate the donor CD4 T cells that drive the autoantibody response.
In general, then, the abnormal CD4 T cell help and the modulating roles
of CD8 T cells seen in cGVHD parallel the participation of T cells in
genetic lupus in mice and human lupus, although these spontaneous
syndromes are presumably not driven by overt alloreactivity.

Systemic lupus erythematosus (SLE) is characterized by a spectrum of auto-
antibodies that targets multiple normal cellular components, particularly
nucleic acids or proteins that are physiologically bound to nucleic acids.
Although SLE is highly diverse in its manifestations, a common theme
is the loss of B cell tolerance to these cellular autoantigens. More than
for any other human condition, several spontaneously arising mouse
models for SLE have been described, beginning with the New Zealand
strains in 1959. These models are largely genetic. In some cases, an
individual gene such as fas or Yaa plays a major role in driving the loss
of tolerance. However, in general the genetic contribution is complex and
involves multiple loci, which are not yet fully defined.

Despite extensive investigations, the failures in immunoregulation that
underlie the genetic SLE models remain poorly understood. It is not known
for sure which B cell tolerance checkpoints are breached in a given model,
and why. The autoantibody response to DNA, Sm, and other autoantigens
resembles the normal response to exogenous antigens: it involves clonal
expansion, somatic mutation, and a pattern of isotype use characteristic of
a T-cell dependent immunization. Thus the cellular dynamics of the response
may be basically normal. Yet the B-cell repertoire is abnormally autoreactive.

In this review we wish to focus more on the role of the T cell in SLE. As
stated above, the loss of B cell tolerance in SLE does appear in general
to require the participation of T cells. Multiple T cells abnormalities have
been described in human and in murine SLE, although in most cases it is
not clear if these are primary or secondary manifestations. Nevertheless,
it is striking how difficult it has been to demonstrate definitively the specificity
of the T cells that provide help for autoantibody production.

The key cellular mechanism in the cGVHD that results in the loss of B cell
tolerance and the production of the autoantibodies typical of SLE is the
cognate interaction of CD4 T cells with an MHC class II determinant on
the B cell surface. A variety of protocols have achieved this interaction.
In general, either the donor/recipient strains are paired in such away
that they only differ at the MHC class II loci, or the CD4 cells are isolated
free of CD8 cells that would recognize MHC class I. If the allorecognition
involves both CD4 T cell interaction with MHC II and CD8 interaction with
MHC I, an acute GVHD occurs, which is immunosuppressive, rather than
immunostimulatory. The DBA/2 (C57BL/6 DBA/2)F1 (B6D2F1) and the
BALB/c (BALB/c A/J)F1 models are exceptions to this rule. The former
has been investigated extensively for a deficiency in CD8 cytotoxic
lymphocytes.

The MHC class II recognition may be at either the I-A or the I-E locus.
However, the autoantibody specificities seen and the degree of immuno-
pathology differ depending on the locus targeted. In one set of experiments,
F1 mice were bred between either B6 or coisogenic bm12 mice and
B10.A(2R) or B10.A(4R) MHC recombinant congenics. The MHC class II
of B6 is I-Ab, while that of bm12 is I-Abm12. These two alleles differ by
only three amino acids, which is sufficient for a full strength MLR (mixed
lymphocyte reaction) between the two strains. Otherwise B6 and bm12
are identical. B10.A(2R) and B10.A(4R) differ only by the expression of
I-E in the former strain, but not in the latter strain. Thus, donor/recipient
combinations could be employed that provided for allogeneic differs only
at I-A, only at I-E, or at both loci.

Results from Busser et al. delineate requirements for this MHC class II
recognition. Utilizing several transgenic mouse strains that express a
more or less constricted CD4 autoreactive repertoire, they showed that
a diverse repertoire was essential to the production of SLE autoantibodies
by MHC II recognition. On the other hand, the non-specific, early polyclonal
B cell activation phase of cGVHD occurred even with a limited CD4 repertoire.

Figure not shown. Chronic GVHD in bm12 C57BL/6 mice. The MHC of the
bm12 donor differs from the MHC of the C57BL/6 recipient just in three
amino acids in the I-A class II molecule. Thus donor CD4 T cells recognize
MHC IIþ B cells as foreign. Donor CD8 T cells see only self MHC I. All T
cells do not express MHC II. Polyclonal activation and specific lupus
autoantibody responses ensue..

Lupus can result from unchecked CD4 T cell cognate help to a polyclonal
population of B cells. CD8 T cells can downregulate this CD4 driven B-cell
hyperactivity through CD8 CTL effectors and can maintain remission,
possibly through memory CD8 T cells. Whether CD8 CTL actually prevent
lupus in normals and fail in lupus prone individuals is not known; however,
data from the P F1 model suggest that therapeutic induction of CD8 CTL
and possibly long term memory cells may be beneficial in preventing or
limiting disease expression. The potential major role played by either
IFNa and IL-21 in both lupus expression and CD8 CTL function remains
to be further defined, but already these cytokines are being targeted in
human or murine lupus.

It is not surprising that the T cells have been shown to have diverse roles in
the autoimmune cGVHD in mice. Donor CD4 T cells drive the host B cell
activation, while host CD4 T cells are required to mature these B cells prior
to their encounter with donor T cells. Donor CD4 T cells also help activate
donor CD8 T cells, which in turn can downregulate or even ablate the
autoimmune response. Donor CD4 T cells license host DC cells, which in
turn can interact with donor CD8 T cells. Host CD8 T cells can suppress
the activity of donor CD8 T cells, and thereby favor the development of
the lupus syndrome. Although the precise mechanisms of T cell participation
in spontaneous lupus are still being defined, it seems reasonable to probe
these syndromes in humans and in mice for T cell mechanism that have
been shown to participate in cGVHD, CD4-B cell interactions almost
certainly are central to the pathogenesis of spontaneous lupus, and they
have been a target of investigation for several decades. If we understood
the peptide specificity of the alloreactive CD4 T cells that drive the formation
of the characteristic lupus autoantibodies, we would have a much clearer
idea where to look for such epitopes in spontaneous disease. Much less
is known about the other T cell activities defined in cGVHD, particularly
those that involve CD8 T cells. This area should invite further detailed
investigation. For example, the striking role of CD8 T cells in the stronger
female disease in the DBA BDF1 model clearly demands that similar
mechanisms be sought for in spontaneous disease.

Understanding Chronic GVHD from Different Angles

Bruce Blazar, Eric S. White, Daniel Couriel
Biol Blood Marrow Transplant 18:S184-S188, 2012
http://dx.doi.org:/10.1016/j.bbmt.2011.10.025

Whereas acute graft-versus-host disease (aGVHD) rates have decreased
with more intensive GVHD preventive agents and use of single and double
umbilical cord blood units as a source of donor cells in adult recipients,
significant chronic GVHD (cGVHD) rates unexpectedly have remained high.
Moreover, granulocyte colony stimulating factor mobilized peripheral blood
stem cell grafts have been associated with an increased overall risk of
cGVHD. As such, cGVHD has emerged as a primary cause of morbidity
and mortality following allogeneic hematopoietic stem cell transplantation.
Progress in developing cGVHD interventional strategies has been hampered
by variable onset and clinical and pathological manifestations of cGVHD, now
better defined by the National Institutes of Health (NIH) consensus conference,
and a dearth of preclinical models that closely mimic the conditions in which
cGVHD is generated and manifested. Although the exact causes of cGVHD
remain unknown, higher antibody levels have been associated with auto-
immunity and implicated in cGVHD. Newly diagnosed patients with
extensive cGVHD had elevated soluble B cell activating factor levels and
anti-double-strand DNA antibodies were found, which was associated with
higher circulating levels of pregerminal center (GC) B cells and post-GC
plasmablasts. B cells from cGVHD patients were hyperresponsive to Toll-like
receptor-9 signaling and have up-regulated CD86 levels.

By using a Cy and low doses of donor T cells, aGVHD was avoided and
cGVHD with BO favored. Histologic changes were similar to the findings in
human cGVHD with peribronchiolar and perivascular cuffing and infiltration
of the airway epithelium. The liver had inflammation and lymphocytic
infiltration, along with collagen deposition. The parotid and submandibular
salivary glands displayed lymphocytic infiltrates in both the bone marrow
and cGVHD groups, likely because of transplantation conditioning.

Treatment of steroid refractory cGVHD patients with rituximab, a B cell–
depleting anti-CD20 monoclonal antibody, has shown a beneficial role in
resolution of the autoimmune disorders such as systemic lupus erythmatosus
and rheumatoid arthritis, andcGVHD, with overall response rates of 29%
to 36% for oral, hepatic, gastrointestinal, and lung cGVHD, and 60% for
cutaneous cGVHD in aggregate data from multiple trials. Thus, we recently
undertook studies to identify the presence of CD41 T helper cells and B2201
B cells in the airways of mice that had BO, tissue-specific antibodies from sera,
and alloantibody deposition in the lung and liver of cGVHD recipients. cGVHD
development was associated with IgG2c deposition in the lung and liver,
abrogated if the donor bone marrow was deficient in mature B cells or
incapable of producing antihost reactive IgG. Robust GC formation was
seen in mice with cGVHD. Alleviation of symptoms in mice that received
B cell–deficient bone marrow confirms the requirement of B cells for lung
dysfunction and inflammation and fibrosis in the lung and liver.

Given a role for IgG antibodies, allo- or auto-Ab binding to the cGVHD organs
could enable tissue destruction or the pathology could be defined by the
specific function of these secreted antibodies. Pathogenic antibody production
therefore is likely to be an important inducer of cGVHD, and targeting this
specific function of the B cells is an attractive strategy for cGVHD. Because
GC B cells display lower susceptibility to rituximab-mediated clearance, probably
because they reside in a nonoptimal environment for antibody-based depletion,
our observation that GC B cells are critical to the development of cGVHD
suggests that agents that are more effective at disrupting the GC might be
more clinically useful. Treatment with LTbR-Ig, a fusion protein that blocks
interactions between LTbR and its ligands, had a direct effect on the
symptoms of cGVHD, at least in part by blocking GC formation and suggest
that LTbR-Ig could be a potential clinical interventional strategy for prevention
and therapy of cGVHD.

Fibrosis is the end result of a number of inflammatory and other injurious events,
resulting in replacement of normal tissue with a dense extracellular matrix (ECM)
scar composed primarily of collagens. While some degree of tissue fibrosis is
considered protective (e.g. in the setting of cutaneous wound healing),
exaggerated or unrelenting ECM deposition with replacement of the normal
tissue architecture is considered pathologic. Fibroproliferative disorders as
a class involving multiple organs (e.g. cGVHD following hematopoietic stem
cell transplant [affecting up to 30% of recipients surviving more than 100 days,
scleroderma [estimated to affect 70,000 in the US], idiopathic pulmonary fibrosis
[estimated to affect 200,000 in the US], hepatic cirrhosis [estimated to affect
up to 400,000 in the US], and renal fibrosis due to diabetic nephropathy and
other causes [estimated to affect over 400,000 in the US]) are a major cause
of morbidity and mortality. Combined, these disorders alone are conservatively
estimated to affect approximately 1 in 300 persons in the United States. When
coupled with a host of other disorders in which tissue fibrosis contributes to
morbidity (e.g. fibroproliferative acute respiratory distress syndrome,
hypersensitivity pneumonitis, solid organ transplant rejection), that estimate
is likely to be much greater.

Wound healing occurs by a highly orchestrated, complex process that has
been well defined. In general, wound repair occurs in 4 stages which overlap
considerably: clotting/coagulation, inflammation, fibroproliferation, and tissue
remodeling. The initial injury leads to a local disruption of epithelial and
endothelial barriers resulting in the elaboration of inflammatory mediators and
extravasation of cells and plasma proteins that serve to achieve hemostasis
and provide a provisional fibrin-rich matrix for the influx of inflammatory and
other reparative cells. Simultaneously, platelet degranulation provides a local
“boost” of vasodilators, growth factors, and ECM proteins that aid in the wound
healing response. Inflammatory cell influx occurs next, with polymorphonuclear
leukocytes (PMNs) arriving first. Following PMN degranulation, mononuclear
cells (macrophages and lymphocytes) arrive next and, along with PMN derived
products, sterilize and remove foreign materials from the wound. This process
also results in the elaboration of cytokines and chemokines designed to
augment the inflammatory response, to promote angiogenesis (allowing for
enhanced nutrient and oxygen delivery to the wound bed), and to recruit
fibroblasts to the wound bed. Fibroblast recruitment and transdifferentiation to
myofibroblasts (or recruitment of already-differentiated myofibroblasts or
fibroblast precursors; this point is still controversial) marks the fibroproliferative
stage, with the result being the elaboration of ECM proteins (collagens,
fibronectins) to repair the tissue defect.

Vorinostat plus tacrolimus and mycophenolate to prevent graft-versus-host
disease after related-donor reduced-intensity conditioning allogeneic
hemopoietic 
stem-cell transplantation: a phase 1/2 trial

Sung Won Choi, T Braun, L Chang, JLM Ferrara, A Pawarode, et al.
Lancet Oncol 2014; 15: 87–95
http://dx.doi.org/10.1016/S1470-2045(13)70512-6

Background Acute graft-versus-host disease (GVHD) remains a barrier to more
widespread application of allogeneic hemopoietic stem-cell transplantation.
Vorinostat is an inhibitor of histone deacetylases and was shown to attenuate
GVHD in preclinical models. We aimed to study the safety and activity of
vorinostat, in combination with standard immunoprophylaxis, for prevention of
GVHD in patients undergoing related-donor reduced-intensity conditioning
hemopoietic stem-cell transplantation. Methods Between March 31, 2009,
and Feb 8, 2013, we did a prospective, single-arm, phase 1/2 study at two
centers in the USA. We recruited adults (aged ≥18 years) with high-risk
hematological malignant diseases who were candidates for reduced-intensity
conditioning hemopoietic stem-cell transplantation and had an available 8/8
or 7/8 HLA matched related donor. All patients received a conditioning regimen
of fl udarabine (40 mg/m² daily for 4 days) and busulfan (3·2 mg/kg daily for
2 days) and GVHD immunoprophylaxis of mycophenolate mofetil (1 g three
times a day, days 0–28) and tacrolimus (0·03 mg/kg a day, titrated to a goal
level of 8–12 ng/mL, starting day –3 until day 180). Vorinostat (either 100 mg
or 200 mg, twice a day) was initiated 10 days before haemopoietic stem-cell
transplantation until day 100. The primary endpoint was the cumulative
incidence of grade 2–4 acute GVHD by day 100. This trial is registered with
ClinicalTrials.gov, number NCT00810602.
Findings 50 patients were assessable for both toxic effects and response;
eight additional patients were included in the analysis of toxic effects. All
patients engrafted neutrophils and platelets at expected times after
hemopoietic stem-cell transplantation. The cumulative incidence of grade
2–4 acute GVHD by day 100 was 22% (95% CI 13–36). The most common
non-hematological adverse events included electrolyte disturbances (n=15),
hyperglycemia (11), infections (six), mucositis (four), and increased activity
of liver enzymes (three). Non-symptomatic thrombocytopenia after
engraftment was the most common hematological grade 3–4 adverse
event (nine) but was transient and all cases resolved swiftly.
Interpretation Administration of vorinostat in combination with standard
GVHD prophylaxis after related-donor reduced-intensity conditioning
hemopoietic stem-cell transplantation is safe and is associated with a
lower than expected incidence of severe acute GVHD. Future studies
are needed to assess the effect of vorinostat for prevention of GVHD in
broader settings of hemopoietic stem-cell transplantation.

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