Cutaneous manifestations of maternal engraftment in patients with severe combined immunodeficiency: a clinicopathologic study

Impact of maternal engrafted cytomegalovirus-specific CD8+ T cells in a patient with severe combined immunodeficiency

Objectives

In patients with severe combined immunodeficiency (SCID), the immune system often fails to eradicate maternal cells that enter the foetus via the placenta, resulting in transplacental maternal engraftment (TME) syndrome. However, the clinical significance of TME has not been comprehensively elucidated.

Methods

Here, we describe a patient with SCID with a novel frameshift IL2RG mutation associated with maternal engrafted CD8⁺ T cells that had been expanded by viral infection. To evaluate the origin of the expanded T cells, we HLA‐typed the myeloid and T cells of the patient and analysed the immunological characteristics of the expanded CD8⁺ T cells using T‐cell receptor (TCR) repertoire and flow cytometry analysis.

Results

In our patient, the maternal engrafted CD8⁺ T cells expanded and exerted in vitro antiviral function against human cytomegalovirus (CMV) infection before and after haematopoietic cell transplantation (HCT). After haploidentical HCT from the maternal donor, maternal engrafted CMV‐specific CD8⁺ T cells were maintained, successfully proliferated and activated against CMV. We found no evidence of acute graft‐versus‐host disease or infectious complications other than recurrent episodes of CMV viraemia, which were well controlled by ganciclovir and, possibly by, the maternal engrafted CMV‐specific CD8⁺ T cells.

Conclusion

Our findings elucidate a possible functional role of TME in controlling CMV infection in patient with SCID and suggest an optimal strategy for donor selection in patients with SCID with TME.

Inborn errors of immunity with atopic phenotypes: A practical guide for allergists

Inborn errors of immunity (IEI) are a heterogeneous group of disorders, mainly resulting from mutations in genes associated with immunoregulation and immune host defense. These disorders are characterized by different combinations of recurrent infections, autoimmunity, inflammatory manifestations, lymphoproliferation, and malignancy. Interestingly, it has been increasingly observed that common allergic symptoms also can represent the expression of an underlying immunodeficiency and/or immune dysregulation.

Very high IgE levels, peripheral or organ-specific hypereosinophilia, usually combined with a variety of atopic symptoms, may sometimes be the epiphenomenon of a monogenic disease. Therefore, allergists should be aware that severe and/or therapy-resistant atopic disorders might be the main clinical phenotype of some IEI. This could pave the way to target therapies, leading to better quality of life and improved survival in affected patients.

Pityriasis Lichenoides: A Large Histopathological Case Series With a Focus on Adnexotropism

INTRODUCTION

Pityriasis lichenoides (PL) is an infrequent skin disorder. The clinical manifestations are usually specific enough for a reliable diagnosis, although the histopathological assessment of a biopsy is sometimes needed to differentiate between PL and a range of other diseases. The objectives of this study were to review cases of PL managed in our hospital, confirm the classical histopathological features of PL, and identify signs that may be of value in the diagnosis of PL.

MATERIALS AND METHODS

All cases of PL assessed in our pathology department between January 2007 and December 2017 were retrieved, and all slides were reviewed. Cases were selected only if a diagnosis of PL was initially suggested by a dermatologist and then confirmed by the histopathological assessment.

RESULTS

Seventy-one cases met the study criteria. The following features were almost always present: vacuolar changes or necrotic keratinocytes (100%), both superficial and deep lymphocytic infiltrates (99%), and the infiltration of lymphocytes into the adnexal epithelium (97%). The inflammatory cells were always small- to medium-sized lymphocytes. There were no eosinophilic infiltrates. Superficial perivascular and/or intraepidermal red blood cells were observed in 83% of cases.

DISCUSSION

We highlighted the presence of a deep dermal lymphocytic infiltrate, with a "T-shaped" periadnexal arrangement along the full length of the follicular and sudoral epithelia. This might be a feature that enables the differentiation of PL from other diseases. Our findings also prompted a number of physiopathological hypotheses for PL.

CONCLUSIONS

Our present results confirmed the classical histological aspects of PL and provided some useful new diagnostic features.

An overview of how on-call consultant paediatricians can recognise and manage severe primary immunodeficiencies

Severe primary paediatric immunodeficiency syndromes are rare and potentially fatal unless suspected, diagnosed and treated early. We provide clinical guidance and support for on-call consultant paediatricians working in secondary level hospitals on how to recognise and manage children with these conditions. Our paper addresses four conditions that risk the most severe outcomes if they are not adequately cared for during on-call periods, such as weekends: severe combined immunodeficiency, haemophagocytic lymphohistiocytosis, severe congenital neutropaenia and chronic granulomatous disease. CONCLUSION: On-call paediatricians are provided with advice on handling the most severe primary immunodeficiencies.

Graft versus host disease and microchimerism in a JAK3 deficient patient

Background

The lymphohematopoietic cells originating from feto-maternal trafficking during pregnancy may cause microchimerism and lead to materno-fetal graft versus host disease (GVHD) in severe combined immunodeficiency (SCID) patients. However, definitive diagnosis between GVHD and Omenn’s syndrome is often difficult based on clinical and immunological phenotypes particularly in the patients with hypomorphic mutations.

Case presentation

A 3-year-old girl with a history of erythroderma and immunodeficiency was studied. The whole exome sequencing method was used to find the disease-causing variants, and T-A cloning and Quantitative Florescence Polymerase Chain Reaction (QF-PCR) methods were utilized to detect the presence of mosaicism or microchimerism. We identified a homozygous missense Janus Kinase 3 mutation (JAK3, c.2324G>A, p.R775H) as a new disease-causing variant in the patient, and the presence of microchimerism with maternal origin was proven as an underlying cause of her clinical presentation.

Conclusion

The findings highlighted the importance of appropriate diagnostic approach in GVHD cases with hypomorphic JAK3 mutations. When analyzing the results of the next generation sequencing, the possibility of microchimerism should be considered based on the context of the disease.

Skin disorders are prominent features in primary immunodeficiency diseases: A systematic overview of current data

Primary immunodeficiency diseases (PIDs) are characterized by an increased risk of infections, autoimmunity, autoinflammation, malignancy, and allergic disorders. Skin disorders are also common clinical features in PIDs and may be among the presenting manifestations. Recognition of specific PID-associated skin conditions in combination with other clinical features as described in the currently used warning signs could raise suspicion of an underlying PID. We aimed to provide a systematically obtained overview of skin disorders and their prevalence in PIDs. Secondary, the prevalence of Staphylococcus (S.) aureus-associated skin disorders and atopy was reviewed, as these are the most prominent skin features in PIDs. A systematic search was performed in EMBASE, MEDLINE, Web of Science, Cochrane, and Google Scholar (up to May 9, 2018). All original observational and experimental human studies that address the presence of skin disorders in PIDs were selected. We rated study quality using the Institute of Health Economics Quality Appraisal Checklist for Case Series Studies. Sixty-seven articles (5030 patients) were included. Study quality ranged from 18.2% to 88.5%. A broad spectrum of skin disorders was reported in 30 PIDs, mostly in single studies with a low number of included patients. An overview of associated PIDs per skin disorder was generated. Data on S. aureus-associated skin disorders and atopy in PIDs were limited. In conclusion, skin disorders are prominent features in PIDs. Through clustering of PIDs per skin disorder, we provide a support tool to use in clinical practice that should raise awareness of PIDs based on presenting skin manifestations.

Maternal T-cell engraftment impedes with diagnosis of a SCID-ADA patient

We describe the case of a child affected by severe combined immunodeficiency (SCID) with adenosine deaminase (ADA) deficiency showing a maternal T-cell engraftment, a finding that has never been reported before. The presence of engrafted maternal T cells was misleading. Although ADA enzymatic levels were suggestive of ADA-SCID, the child did not present the classical signs of ADA deficiency; therefore, the initial diagnosis was of a conventional SCID. However, ADA toxic metabolites and molecular characterization confirmed this diagnosis. Polyethylene glycol-modified bovine (PEG) ADA therapy progressively decreased the number of maternal engrafted T cells. The child was grafted with full bone marrow from a matched unrelated donor, after a reduced conditioning regimen, and the result was the complete immunological reconstitution.

•

Maternal engrafted T-cell in ADA-SCID

•

Engrafted T cells can be misleading for diagnosis

•

Diagnostic testing is critical

Maternal T and B cell engraftment in two cases of X-linked severe combined immunodeficiency with IgG1 gammopathy

X-linked severe combined immunodeficiency (X-SCID), caused by defects in the common gamma chain, is typically characterized by T and NK cell defects with the presence of B cells. T cell dysfunction and impaired class-switch recombination of B cells mean that patients typically have defects in class-switched immunoglobulins (IgG, IgA, and IgE) with detectable IgM. Here, we describe two patients with X-SCID with IgG1 gammopathy, in whom we identified maternal T and B cell engraftment. Exclusively, maternal B cells were found among the IgD^-CD27⁺ class-switched memory B cells, whereas the patients' B cells remained naïve. In vitro stimulation with CD40L+IL-21 revealed that peripheral blood cells from both patients produced only IgG1. Class-switched maternal B cells had restricted receptor repertoires with various constant regions and few somatic hypermutations. In conclusion, engrafted maternal B cells underwent class-switch recombination and produced immunoglobulin, causing hypergammaglobulinemia in patients with X-SCID.

Transplacental maternal engraftment and posttransplantation graft-versus-host disease in children with severe combined immunodeficiency

BACKGROUND

Graft-versus-host disease (GVHD) is a complication of allogeneic hematopoietic stem cell transplantation (HSCT). Transplacental maternal engraftment (TME), the presence of maternal T cells in peripheral blood before transplantation, is detectable in a significant proportion of patients with severe combined immunodeficiency (SCID). Although the presence of TME is associated with a decreased risk of rejecting a maternal graft, it is unknown whether TME plays a role in development of GVHD after HSCT.

OBJECTIVE

The purpose of this study was to determine whether the presence of pretransplantation TME is associated with posttransplantation GVHD in patients with SCID.

METHODS

This was an institutional retrospective review of 74 patients with SCID undergoing transplantation between 1988 and 2014. The incidence of acute graft-versus-host disease (aGVHD) was compared in patients with versus those without TME. Confounding variables, such as donor type and conditioning regimen, were included in a multivariate regression model.

RESULTS

TME was identified in 35 of 74 children. Post-HSCT aGVHD developed with an incidence of 57.1% versus 17.9% in those without TME (P < .001). In univariate analysis donor type (mother) and GVHD prophylaxis (T-cell depletion) were also significant predictors of aGVHD. In multivariate analysis TME and chemotherapy conditioning were independent risk factors for the development of aGVHD (relative risk, 2.75, P = .006 and relative risk, 1.42, P = .02, respectively).

CONCLUSION

TME independently predicts the development of posttransplantation aGVHD, even when controlling for donor type and conditioning used. The presence of TME should be considered when assessing the risk of aGVHD in patients with SCID and designing the approach for GVHD prophylaxis.

Severe combined immunodeficiency--an update

Severe combined immunodeficiencies (SCIDs) are a group of inherited disorders responsible for severe dysfunctions of the immune system. These diseases are life-threatening when the diagnosis is made too late; they are the most severe forms of primary immunodeficiency. SCID patients often die during the first two years of life if appropriate treatments to reconstitute their immune system are not undertaken. Conventionally, SCIDs are classified according either to the main pathway affected by the molecular defect or on the basis of the specific immunologic phenotype that reflects the stage where the blockage occurs during the differentiation process. However, during the last few years many new causative gene alterations have been associated with unusual clinical and immunological phenotypes. Many of these novel forms of SCID also show extra-hematopoietic alterations, leading to complex phenotypes characterized by a functional impairment of several organs, which may lead to a considerable delay in the diagnosis. Here we review the biological and clinical features of SCIDs paying particular attention to the most recently identified forms and to their unusual or extra-immunological clinical features.

Screening for and treatments of congenital immunodeficiency diseases

Although newborn screening (NBS) for inborn errors of metabolism has been successfully utilized in the US for decades, only recently has this screening program expanded to include disorders of immunity. Severe combined immunodeficiency (SCID) became the first disorder of immunity to be screened on a population wide basis in 2008. While NBS for SCID has been successful, the implementation of population-based screening programs is not without controversy, and there remain barriers to the nationwide implementation of this test. In addition, as the program has progressed we have learned of new challenges in the management of newborns that fail this screen.

Co-existence of clonal expanded autologous and transplacental-acquired maternal T cells in recombination activating gene-deficient severe combined immunodeficiency

It is commonly accepted that the presence of high amounts of maternal T cells excludes Omenn syndrome (OS) in severe combined immunodeficiency (SCID). We report a SCID patient with a novel mutation in the recombination activating gene (RAG)1 gene (4-BP DEL.1406 TTGC) who presented with immunodeficiency and OS. Several assays, including representatives of specific T cell receptors (TCR), Vβ families and TCR-γ rearrangements, were performed in order to understand more clearly the nature and origin of the patient's T cells. The patient had oligoclonal T cells which, based on the patient-mother human leucocyte antigen (HLA)-B50 mismatch, were either autologous or of maternal origin. These cell populations were different in their numbers of regulatory T cells (T(reg)) and the diversity of TCR repertoires. This is the first description of the co-existence of large amounts of clonal expanded autologous and transplacental-acquired maternal T cells in RAG1-deficient SCID.

Combined immunodeficiencies with nonfunctional T lymphocytes

Immunodeficiencies with nonfunctional T cells comprise a heterogeneous group of conditions characterized by altered function of T lymphocytes in spite of largely preserved T cell development. Some of these forms are due to hypomorphic mutations in genes causing severe combined immunodeficiency. More recently, advances in human genome sequencing have facilitated the identification of novel genetic defects that do not affect T cell development, but alter T cell function and homeostasis. Along with increased susceptibility to infections, these conditions are characterized by autoimmunity and higher risk of malignancies. The study of these diseases, and of corresponding animal models, has provided fundamental insights on the mechanisms that govern immune homeostasis.

Characterizing T cells in SCID patients presenting with reactive or residual T lymphocytes

INTRODUCTION

Patients with severe combined immunodeficiency (SCID) may present with residual circulating T cells. While all cells are functionally deficient, resulting in high susceptibility to infections, only some of these cells are causing autoimmune symptoms.

METHODS

Here we compared T-cell functions including the number of circulating CD3(+) T cells, in vitro responses to mitogens, T-cell receptor (TCR) repertoire, TCR excision circles (TREC) levels, and regulatory T cells (Tregs) enumeration in several immunodeficinecy subtypes, clinically presenting with nonreactive residual cells (MHC-II deficiency) or reactive cells. The latter includes patients with autoreactive clonal expanded T cell and patients with alloreactive transplacentally maternal T cells.

RESULTS

MHC-II deficient patients had slightly reduced T-cell function, normal TRECs, TCR repertoires, and normal Tregs enumeration. In contrast, patients with reactive T cells exhibited poor T-cell differentiation and activity. While the autoreactive cells displayed significantly reduced Tregs numbers, the alloreactive transplacentally acquired maternal lymphocytes had high functional Tregs.

CONCLUSION

SCID patients presenting with circulating T cells show different patterns of T-cell activity and regulatory T cells enumeration that dictates the immunodeficient and autoimmune manifestations. We suggest that a high-tolerance capacity of the alloreactive transplacentally acquired maternal lymphocytes represents a toleration advantage, yet still associated with severe immunodeficiency.

Skin manifestations in primary immunodeficient children

Skin manifestations are prevalent in primary immunodeficiency disorders (PID). In a large proportion of patients, they manifest as presenting signs and serve as important factors for the early diagnosis of PID. Only a few studies describing the spectrum of skin disorders in PID are available. The objective of the current study was to determine the prevalence and characteristics of skin manifestations in children with PID. Participants were 128 pediatric patients with PID (aged <16 years) registered prospectively over 6 years. Skin manifestations were observed in 61 patients (48%), and those manifestations were the presenting features in 50 (39% of total PID and 82% of those with skin lesions). Skin infections were the most prevalent manifestations, seen in 39 patients (30%), followed by eczemas in 24 (19%). Skin infections were significantly more prevalent in those with congenital defects in phagocyte number, function, or both, as well as in those with well-defined immunodeficiencies. Although widely present in all participants with PID, eczema was a consistent feature (100%) in patients with hyper IgE syndrome and Wiskott-Aldrich syndrome (WAS). Erythroderma of infancy with diffuse alopecia was seen exclusively in patients with severe combined immunodeficiency disorders, telangiectasia in patients with ataxia telangiectasia, and partial albinism with silvery gray hair in those with Chediak-Higashi syndrome. Autoimmune skin manifestations were observed in 6% of reported cases of PID. This study highlights the importance of awareness of skin manifestations of PID to assist in the early diagnosis and management of these disorders.

Genetics of SCID

Human SCID (Severe Combined Immunodeficiency) is a prenatal disorder of T lymphocyte development, that depends on the expression of numerous genes. The knowledge of the genetic basis of SCID is essential for diagnosis (e.g., clinical phenotype, lymphocyte profile) and treatment (e.g., use and type of pre-hematopoietic stem cell transplant conditioning).Over the last years novel genetic defects causing SCID have been discovered, and the molecular and immunological mechanisms of SCID have been better characterized. Distinct forms of SCID show both common and peculiar (e.g., absence or presence of nonimmunological features) aspects, and they are currently classified into six groups according to prevalent pathophysiological mechanisms: impaired cytokine-mediated signaling; pre-T cell receptor defects; increased lymphocyte apoptosis; defects in thymus embryogenesis; impaired calcium flux; other mechanisms.This review is the updated, extended and largely modified translation of the article "Cossu F: Le basi genetiche delle SCID", originally published in Italian language in the journal "Prospettive in Pediatria" 2009, 156:228-238.

Delayed presentation of severe combined immunodeficiency due to prolonged maternal T cell engraftment

Severe combined immunodeficiency (SCID) is a primary immunodeficiency disorder with heterogenous genetic etiologies. We describe a typical case in a 9-year-old boy that was masked by a clinically functional maternal T cell engraftment leading to late presentation with Pneumocystis jiroveci pneumonia and cytomegalovirus infection, probably following exhaustion of maternally engrafted cells. Based on immunological findings, he had a T- B+SCID phenotype.This report suggests that in rare cases, engrafted maternal T cell might persist for long time leading to partial constitution of immune function and delayed clinical presentation of SCID.

Partially corrected X-linked severe combined immunodeficiency: long-term problems and treatment options

Rapid progress has been made from the identification of the molecular defects causing X-linked severe combined immune deficiency (X-SCID) to the development of cutting-edge therapeutic approaches such as hematopoietic stem cell transplant and gene therapy for XSCID. Successful treatment of XSCID has created a new population of patients, many of whom are now adolescents and young adults and are facing a variety of chronic problems secondary to partial correction of their underlying disease. This review focuses on the clinical challenges facing these patients (and their caregivers) and provides an overview of some of the treatment options available, including gene therapy.

Severe combined immunodeficiency (SCID)-associated dyschromia with subsequent repigmentation: a report of two patients

Severe combined immunodeficiency (SCID) often presents with mucosal infections, cutaneous infections and eczematous rashes. We present two patients with history of SCID diagnosed at an early age who experienced diffuse dyschromia associated with their bone marrow and stem cell transplants. Dyschromias may be caused by numerous factors including medications, genetics, environmental contacts, or as a sequela of underlying chronic disease. These case reports describe progressive repigmentation to original skin color after the occurrence of dyschromia in two patients with SCID.

Maternal T-cell engraftment associated with severe hemophagocytosis of the bone marrow in untreated X-linked severe combined immunodeficiency

Maternal engraftment of T cells in severe combined immunodeficiency can lead to graft-versus-host disease of the skin and liver. We report the case of an infant with X-linked severe combined immunodeficiency, confirmed by DNA sequencing of the common gamma chain gene locus, in which this disorder's characteristic peripheral lymphocyte phenotype [T(-)B(+)NK(-)] was obscured by the postnatal onset of hemophagocytic syndrome that included severe B-cell lymphopenia, neutropenia, and anemia. Hemophagocytosis was most likely owing to maternal graft-versus-host disease, as perforin-expressing CD8 T cells, presumably of maternal origin, were prominent in the bone marrow and there was no concurrent severe infection.

Rituximab for the treatment of post-bone marrow transplantation refractory hemolytic anemia in a child with Omenn's syndrome

Omenn's syndrome is a rare severe combined immunodeficiency that kills affected subjects before the end of the first year of life unless patients are treated with bone marrow transplantation (BMT). Unfortunately, post-BMT patients may develop autoimmune diseases, such as autoimmune hemolytic anemia (AIHA), which sometimes fails to respond to standard therapies. Rituximab is a chimeric, human, immunoglobulin G1/k monoclonal antibody specific for the CD20 antigen expressed on the surface of B lymphocytes. Rituximab is currently only labeled for treatment of B-cell lymphoproliferative disorders, such as B-cell non-Hodgkin's lymphoma and follicular lymphoma; however, it is also employed in the treatment of a variety of disorders mediated by auto-antibodies, such as AIHA and transplant-related autoimmune disorders. Herein, we describe the case of a 23-month-old male child with Omenn's syndrome, who had undergone BMT and was successfully treated with rituximab (375 mg/m(2) intravenously, weekly for three times) for refractory post-BMT hemolytic anemia. Our findings evidence that rituximab should be considered for treatment of post-BMT AIHA refractory to traditional therapy also in children with primary immunodeficiencies; furthermore, rituximab might represent a means to obtain remissions without the toxic effects associated with corticosteroid and immunosuppressive agents.

Skin infiltration of CD56brightCD16-natural killer cells in a case of X-SCID with Omenn syndrome-like manifestations

We observed a patient with X-linked severe combined immunodeficiency (X-SCID) with Omenn syndrome-like manifestations. X-linked inheritance, absence of CD132 expression and impaired response to interleukin-2 (IL-2) indicated that the case is typical of X-SCID due to gamma(c) defect. However, this case was unusual in that circulating natural killer (NK) cells were increased and nearly half of these NK cells exhibited the CD56(bright) CD16(-) phenotype. A missense mutation was found within exon 5 of the IL2RG gene. The identical mutation was detected within NK, CD4(+) T and B cells. Engraftment of maternally derived NK cells or gene reversion was ruled out. The erythroderma-like skin lesion was characterized by infiltration of the dermis by CD56(bright) NK cells admixed with CD1a(+) dendritic cells (DC). Expression of mRNA for inflammatory cytokines was significantly enhanced within the skin. This may be the first human case to demonstrate that close cell-to-cell contact between DC and NK cells provides an effective alternative pathway for NK cell differentiation/activation in vivo.

The changing face of graft-versus-host disease

Despite advances in the procedure and posttransplantation immunosuppressive therapy, more than half of allogeneic hematopoietic stem cell transplant (HSCT) recipients develop graft-versus-host disease (GVHD), which remains a major cause of morbidity and mortality. Modern HSCT protocols have resulted in substantial alterations in the timing and relative incidences of acute and chronic GVHD, making traditional classification schemes obsolete. This article reviews major changes in HSCT during the past decade, evolving concepts of acute and chronic GVHD (including new diagnostic criteria) and the expanding spectrum of cutaneous GVHD. It focuses on observations that have led to a better delineation of the full constellation of skin findings in chronic cutaneous GVHD, including lichen sclerosus, morpheaform lesions, and eosinophilic fasciitis. Recent insights into pathogenesis of GVHD, lessons from GVHD arising in settings outside HSCT, and therapeutic advances also are highlighted.

Review of 54 patients with complete DiGeorge anomaly enrolled in protocols for thymus transplantation: outcome of 44 consecutive transplants

The purpose of this study was to characterize a large group of infants with complete DiGeorge anomaly and to evaluate the ability of thymus transplantation to reconstitute immune function in these infants. DiGeorge anomaly is characterized by varying defects of the heart, thymus, and parathyroid glands. Complete DiGeorge anomaly refers to the subgroup that is athymic (< 1%). The characteristics of 54 subjects at presentation and results from 44 consecutive thymus transplantations are reported. Remarkably, only 52% had 22q11 hemizygosity and only 57% had congenital heart disease requiring surgery. Thirty-one percent developed an atypical phenotype with rash and lymphadenopathy. To date, 33 of 44 subjects who received a transplant survive (75%) with post-transplantation follow-up as long as 13 years. All deaths occurred within 12 months of transplantation. All 25 subjects who were tested 1 year after transplantation had developed polyclonal T-cell repertoires and proliferative responses to mitogens. Adverse events developing after transplantation included hypothyroidism in 5 subjects and enteritis in 1 subject. In summary, diagnosis of complete DiGeorge anomaly is challenging because of the variability of presentation. Thymus transplantation was well tolerated and resulted in stable immunoreconstitution in these infants.

Immunodeficiencies with Autoimmune Consequences

Far from being mutually exclusive, immunodeficiency and autoimmunity may occur simultaneously. During the last years, analysis of Autoimmune Polyendocrinopathy--Candidiasis--Ectodermal Dystrophy (APECED) and Immunodysregulation--Polyendocrinopathy--Enteropathy--X-linked (IPEX), two rare monogenic forms of immunodeficiency associated with autoimmunity, has led to the identification of Auto Immune Regulator (AIRE) and Forkhead Box P3 (FOXP3), essential transcriptional regulators, involved in central tolerance and peripheral immune homeostasis, respectively. Characterization of the molecular and cellular mechanisms involved in APECED, and recognition that AIRE expression is sustained by effective thymopoiesis, has recently allowed to define that the autoimmunity of Omenn syndrome, a combined immunodeficiency due to defects of V(D)J recombination, also results from defective expression of AIRE. The implications of identification of the basis of autoimmunity in these rare forms of immunodeficiency have important implications for a better understanding of more common autoimmune disorders, and for development of novel therapeutic approaches.

Life-threatening cutaneous conditions in neonates

One of the major medical concerns in neonates is their vulnerability to life-threatening complications. Early diagnosis of potentially serious medical conditions is essential in prevention of such complication by prompt administration of appropriate treatments. Recognition of cutaneous manifestations of potentially fatal diseases may assist a clinician in management of newborns. To overview the full spectrum of this category of conditions, Medline search was performed for cases of cutaneous manifestations associated with mortality during the first month of live that were published in the English language literature since 1977. This is a concise review of the clinical aspects of most of the potentially life-threatening disorders in neonates divided by basic morphology of their cutaneous manifestations.

Complete DiGeorge syndrome: Development of rash, lymphadenopathy, and oligoclonal T cells in 5 cases

BACKGROUND

Five patients with DiGeorge syndrome presented with infections, skin rashes, and lymphadenopathy after the newborn period. T-cell counts and function varied greatly in each patient. Initial laboratory testing did not suggest athymia in these patients.

OBJECTIVE

The purpose of this study was to determine whether the patients had significant immunodeficiency.

METHODS

Research testing of peripheral blood included immunoscope evaluation of T-cell receptor beta variable gene segment repertoire diversity, quantification of T-cell receptor rearrangement excision circles, and detection of naive T cells (expressing CD45RA and CD62L).

RESULTS

The patients were classified as having DiGeorge syndrome on the basis of syndromic associations and heart, parathyroid, and immune abnormalities. Immunoscope evaluation revealed that the T-cell repertoires were strikingly oligoclonal in all patients. There were few recent thymic emigrants, as indicated by the very low numbers of naive T cells (<50/mm(3)) and the absence of T-cell receptor rearrangement excision circles. These studies showed that all 5 patients were athymic. Two patients died, one from infection. No thymus was found during the complete autopsy performed on one patient.

CONCLUSION

Patients with DiGeorge syndrome, skin rash, and lymphadenopathy should undergo analysis of naive T-cell numbers and of T-cell receptor beta variability segment repertoire to determine whether they are athymic, even if they have T cells with mitogen responsiveness. It is important for physicians to realize that patients with complete DiGeorge syndrome remain profoundly immunodeficient after development of these atypical features (rash, lymphadenopathy, and oligoclonal T cells). Prompt diagnosis is necessary for appropriate management.