Autoimmune lymphoproliferative syndrome

A rare immunological disease, caspase 8 deficiency: case report and literature review

BACKGROUND

Caspase-8 is a molecule in the FAS pathway that initiates apoptosis. One of the rarest autoimmune lymphoproliferative syndromes is caspase-8 deficiency. Immunodeficiency, splenomegaly, and lymphadenopathy are the common symptoms of this condition.

CASE PRESENTATION

A two-year-old boy entered this study with a fever of unknown origin (FUO) and dysentery. Moreover, he suffered from failure to thrive and was allergic to the cow's milk protein. His fever and dysentery did not respond to antibiotic therapy. The colonoscopy revealed diffuse ulcerations regions in the sigmoid along with skipped areas, mimicking Crohn's disease aphthous lesions. He represented very early-onset inflammatory bowel disease (IBD) and was diagnosed with the caspase-8 deficiency.

CONCLUSION

There can be diarrhea or dysentery as the first or main symptoms of inborn errors of immunity (IEIs). The cause of diarrhea and dysentery in this case was early-onset IBD. One of the symptoms of IEIs such as caspase-8 deficiency is early-onset of IBD. Patients with early-onset had normal T cell count and low or normal immunoglobulin levels with insufficient immune response.

Neonatal Autoimmune Lymphoproliferative Syndrome: A Case Report and A Brief Review

The authors are reporting a case of autoimmune lymphoproliferative syndrome in a newborn who presented with massive hepatosplenomegaly, thrombocytopenia, and anemia at birth. Antenatal ultrasound revealed a fetus with hepatosplenomegaly. The infant was treated with steroids and sirolimus and is doing well at 4 years of age. This is the first case report of autoimmune lymphoproliferative syndrome presenting as hepatosplenomegaly during fetal life.

Dual Role of Fas/FasL-Mediated Signal in Peripheral Immune Tolerance

Fas-mediated apoptosis contributes to physiological and pathological cellular processes, such as differentiation and survival. In particular, the roles of Fas in immune cells are complex and critical for the maintenance of immune tolerance. The precise pathways and unique functions associated with Fas/FasL-mediated signaling in the immune system are known. The dual character of Fas/FasL-mediated immune regulation that induces beneficial or harmful effects is associated with the onset or development of immune disorders. Studies on mutations in genes encoding Fas and FasL gene of humans and mice contributed to our understanding of the pathogenesis of autoimmune diseases. Here, we review the opposing functions of Fas/FasL-mediated signaling, bilateral effects of Fas/FasL on in immune cells, and complex pathogenesis of autoimmunity mediated by Fas/FasL.

Spontaneous Coronary Artery Dissection: Report of 3 Cases and Literature Review Hormonal, Autoimmune, Morphological Factors

The number of cases with spontaneous coronary artery dissection (SCAD) is considered to be being underestimated because of a large amount of SCAD leading to sudden death without previous diagnosis. Besides, not only in clinics but also in autopsy practice, correct diagnosis of SCAD is important to prevent forensic malpractice.The article is intended to discuss the pathological findings through the forensic point of view for improving the malpractice expertise in scope of clinicians' timely antemortem diagnosis according to risk factors and in scope of forensic pathologists' the cause of death determination ability according to macroscopical and microscopical findings of the autopsy.In 3 cases reported, the main characteristics were the female sex, pregnancy history and a sudden death without any trauma. However, although there are many women giving birth or using oral contraceptives, only some of them are facing with SCAD. This suggests the possibility of some hereditary factors, whereas hereditary characteristics may be understood in many different ways like hormone-releasing regulating mechanisms as well as immunity, morphology, or any other mechanism. For instance, autoimmunity has been also a hereditary underlying factor for vessel injury considered in presented cases.

The Ying and Yang of STAT3 in Human Disease

The transcription factor signal transducer and activator of transcription 3 (STAT3) is a critical regulator of multiple, diverse cellular processes. Heterozgyous, germline, loss-of-function mutations in STAT3 lead to the primary immune deficiency Hyper-IgE syndrome. Heterozygous, somatic, gain-of-function mutations in STAT3 have been reported in malignancy. Recently, germline, heterozygous mutations in STAT3 that confer a gain-of-function have been discovered and result in early-onset, multi-organ autoimmunity. This review summarizes what is known about the role of STAT3 in human disease.

An Improved Acute Gouty Arthritis Rat Model and Therapeutic Effect of Rhizoma Dioscoreae Nipponicae on Acute Gouty Arthritis Based on the Protein-Chip Methods

Rhizoma Dioscoreae Nipponicae (RDN) is an herbal medicine. In the theories of Traditional Chinese Medicine (TCM), the function of RDN is to expel wind and remove dampness. Inflammatory mechanisms play an important role in the pathological process and prognosis of acute gouty arthritis (AGA). The aim of this study was to determine the specially expressed proteins through testing the proteins of the synovium in rats with AGA. The animal model of AGA was set up by Monosodium urate crystal (MSU) combined with hypoxanthine (HX), which was ameliorated in our previous experiment. Blood samples for measurement of serum uric acid were collected prior to sacrifice. Outcomes were assessed (two days after injection) by histological stain and protein quantitation. Three chips of RayBioⓇHuman Label-based Antibody Array I were applied to detect 90 proteins in the synovium tissue of AGA rats. 14 differently expressed proteins were found in the synovium of AGA rats, and nine of them were first found in this model. There were seven up-regulated and seven down-regulated proteins, both TRAIL and Neuropilin-2 could be identified as key contributors to the pathomechanism of AGA.

Autoimmune Lymphoproliferative Syndrome

The autoimmune lymphoproliferative syndrome (ALPS) is a rare disease. ALPS is an inherited condition that affects both sexes. ALPS is not cancer, it is not infectious, and its incidence has not yet been estimated. ALPS generally does not lead to death and most individuals with ALPS are able to live normal lives. ALPS is a disorder associated with abnormal lymphocyte apoptosis, lymphoproliferation, and autoimmunity. Serologic testing is critical in the evaluation of these individuals. Lymphoproliferation in ALPS patients is generally benign, but they are at increased risk for the development of Hodgkin's and non-Hodgkin's lymphoma. It is characterized by massive lymphoadenopathy, splenomegaly, autoimmunity including episodes of immune hemolityc anemia, thrombocytopenia, and neutropenia. ALPS patients have lymphocytosis and a number of lymphocyte abnormalities, including the marked expansion of T lymphocytes that express alpha/beta T-cell receptors, but neither CD4 nor CD8 surface markers (TCR alpha/beta+; CD4-; CD8- cells).

Laboratory evaluation of primary immunodeficiencies

Primary immunodeficiencies are congenital disorders caused by defects in different elements of the immune system. Affected patients usually present clinically with recurrent infections, severe infections, or both, as well as autoimmune phenomena that are associated with many of these disorders. Early diagnosis is essential for referral to specialized care centers and the prompt initiation of appropriate therapy. In this article the authors describe a general approach for the investigation of the most common primary immunodeficiencies, outlining the typical clinical symptoms and most appropriate laboratory investigations.

Restimulation-induced apoptosis of T cells is impaired in patients with X-linked lymphoproliferative disease caused by SAP deficiency

X-linked lymphoproliferative disease (XLP) is a rare congenital immunodeficiency that leads to an extreme, usually fatal increase in the number of lymphocytes upon infection with EBV. It is most commonly defined molecularly by loss of expression of SLAM-associated protein (SAP). Despite this, there is little understanding of how SAP deficiency causes lymphocytosis following EBV infection. Here we show that T cells from individuals with XLP are specifically resistant to apoptosis mediated by TCR restimulation, a process that normally constrains T cell expansion during immune responses. Expression of SAP and the SLAM family receptor NK, T, and B cell antigen (NTB-A) were required for TCR-induced upregulation of key pro-apoptotic molecules and subsequent apoptosis. Further, SAP/NTB-A signaling augmented the strength of the proximal TCR signal to achieve the threshold required for restimulation-induced cell death (RICD). Strikingly, TCR ligation in activated T cells triggered increased recruitment of SAP to NTB-A, dissociation of the phosphatase SHP-1, and colocalization of NTB-A with CD3 aggregates. In contrast, NTB-A and SHP-1 contributed to RICD resistance in XLP T cells. Our results reveal what we believe to be novel roles for NTB-A and SAP in regulating T cell homeostasis through apoptosis and provide mechanistic insight into the pathogenesis of lymphoproliferative disease in XLP.

The RASopathies: developmental syndromes of Ras/MAPK pathway dysregulation

The Ras/mitogen activated protein kinase (MAPK) pathway is essential in the regulation of the cell cycle, differentiation, growth and cell senescence, all of which are critical to normal development. It is therefore not surprising that its dysregulation has profound effects on development. A class of developmental syndromes, the 'RASopathies', is caused by germline mutations in genes that encode protein components of the Ras/MAPK pathway. The vast majority of these mutations result in increased signal transduction down the Ras/MAPK pathway, but usually to a lesser extent than somatic mutations associated with oncogenesis. Each syndrome exhibits unique phenotypic features, however, since they all cause dysregulation of the Ras/MAPK pathway, there are numerous overlapping phenotypic features between the syndromes, including characteristic facial features, cardiac defects, cutaneous abnormalities, neurocognitive delay and a predisposition to malignancies. Here we review the clinical and underlying molecular basis for each of these syndromes.

Critical role for BIM in T cell receptor restimulation-induced death

BACKGROUND

Upon repeated or chronic antigen stimulation, activated T cells undergo a T cell receptor (TCR)-triggered propriocidal cell death important for governing the intensity of immune responses. This is thought to be chiefly mediated by an extrinsic signal through the Fas-FasL pathway. However, we observed that TCR restimulation still potently induced apoptosis when this interaction was blocked, or genetically impaired in T cells derived from autoimmune lymphoproliferative syndrome (ALPS) patients, prompting us to examine Fas-independent, intrinsic signals.

RESULTS

Upon TCR restimulation, we specifically noted a marked increase in the expression of BIM, a pro-apoptotic Bcl-2 family protein known to mediate lymphocyte apoptosis induced by cytokine withdrawal. In fact, T cells from an ALPS type IV patient in which BIM expression is suppressed were more resistant to restimulation-induced death. Strikingly, knockdown of BIM expression rescued normal T cells from TCR-induced death to as great an extent as Fas disruption.

CONCLUSION

Our data implicates BIM as a critical mediator of apoptosis induced by restimulation as well as growth cytokine withdrawal. These findings suggest an important role for BIM in eliminating activated T cells even when IL-2 is abundant, working in conjunction with Fas to eliminate chronically stimulated T cells and maintain immune homeostasis.

REVIEWERS

This article was reviewed by Dr. Wendy Davidson (nominated by Dr. David Scott), Dr. Mark Williams (nominated by Dr. Neil Greenspan), and Dr. Laurence C. Eisenlohr.

Understanding systemic lupus erythematosus physiopathology in the light of primary immunodeficiencies

INTRODUCTION

Associations between systemic lupus erythematosus (SLE) and primary immunodeficiencies (PIDs) were analyzed to gain insight into the physiopathology of SLE. Some PIDs have been consistently associated with SLE or lupus-like manifestations: (a) homozygous deficiencies of the early components of the classical complement pathway in the following decreasing order: in C1q, 93% of affected patients developed SLE; in C4, 75%; in C1r/s, 57%; and in C2, up to 25%; (b) female carriers of X-linked chronic granulomatous disease allele; and (c) IgA deficiency, present in around 5% of juvenile SLE.

DISCUSSION

In the first two groups, disturbances of cellular waste-disposal have been proposed as the main mechanisms of pathogenesis. On the other hand and very interestingly, there are PIDs systematically associated with several autoimmune manifestations in which SLE has not been described, such as autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX), and autoimmune lymphoproliferative syndrome (ALPS), suggesting that mechanisms considered as critical players for induction and maintenance of tolerance to autoantigens, such as (1) AIRE-mediated thymic negative selection of lymphocytes, (2) Foxp3+ regulatory T cell-mediated peripheral tolerance, and (3) deletion of auto-reactive lymphocytes by Fas-mediated apoptosis, could not be relevant in SLE physiopathology. The non-description of SLE and neither the most characteristic SLE clinical features among patients with agammaglobulinemia are also interesting observations, which reinforce the essential role of B lymphocytes and antibodies for SLE pathogenesis.

CONCLUSION

Therefore, monogenic PIDs represent unique and not fully explored human models for unraveling components of the conundrum represented by the physiopathology of SLE, a prototypical polygenic disease.

Analysis of single nucleotide polymorphisms in the FAS and CTLA-4 genes of peripheral T-cell lymphomas

Angioimmunoblastic T-cell lymphoma (AILT) represents a subset of T-cell lymphomas but resembles an autoimmune disease in many of its clinical aspects. Despite the phenotype of effector T-cells and high expression of FAS and CTLA-4 receptor molecules, tumor cells fail to undergo apoptosis. We investigated single nucleotide polymorphisms (SNPs) of the FAS and CTLA-4 genes in 94 peripheral T-cell lymphomas. Although allelic frequencies of some FAS SNPs were enriched in AILT cases, none of these occurred at a different frequency compared to healthy individuals. Therefore, SNPs in these genes are not associated with the apoptotic defect and autoimmune phenomena in AILT.

The autoimmune lymphoproliferative syndrome: an experiment of nature involving lymphocyte apoptosis

Autoimmune lymphproliferative syndrome (ALPS) is a human disorder that has been characterized in the past two decades at both a functional and a genetic level. The underlying basis for this disorder is a defect in lymphocyte apoptosis that alters immune homeostasis resulting in an expansion of a normally rare circulating lymphocyte, the alpha beta double negative T cell. The abnormality in Fas mediated apoptosis underlying ALPS serves as a risk factor for autoimmunity involving blood cells and the development of lymphoma. There remain patients with a diagnosis of ALPS but without a defined genetic defect and current investigations are focusing on fully characterizing this patient subgroup.

Childhood immune thrombocytopenic purpura: diagnosis and management

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by a low circulating platelet count caused by destruction of antibody-sensitized platelets in the reticuloendothelial system. ITP can be classified as childhood versus adult, acute versus chronic, and primary versus secondary. Persistence of thrombocytopenia defines the chronic form of the disorder. Secondary causes of ITP include collagen vascular disorders, immune deficiencies, and some chronic infections. This review focuses on the diagnosis and management of children who have acute and chronic ITP. Emphasis is placed on areas of controversy and new therapies.

Tolerance and autoimmunity: lessons at the bedside of primary immunodeficiencies

The recent progress in the genetic characterization of many primary immunodeficiencies (PIDs) allows for a better understanding of immune molecular and cellular mechanisms. The present chapter discusses associations between PIDs and autoimmune diseases (AIDs) in this new light. PIDs are classified according to the frequency of association with AIDs, defining four groups of conditions: systematic (more than 80% of all patients), strong (10-80%), mild (less than 10%), and absent (no available descriptions). Several general conclusions could be drawn: (1) pathological autoimmune (AI) manifestations are very frequently associated with PIDs, indicating that, contrary to conventional notions, antimicrobial protection and natural tolerance to body tissues share many basic mechanisms; (2) in some gene defects, association is so strong that one could speak of "monogenic" AIDs; (3) basic types of PIDs are selectively associated with AID of a particular set of target tissues; (4) while for some gene defects, current theory satisfactorily explains pathogenesis of the corresponding AID, other situations suggest extensive gaps in the present understanding of natural tolerance; and (5) not exceptionally, observations on the AI phenotype for the same gene defect in mouse and man are not concordant, perhaps owing to the limited genetic diversity of mouse models, often limited to a single mouse strain. Overall, clinical observations on PID support the new paradigm of "dominant" tolerance to self-components, in which AID owes to deficits in immune responses (i.e., in regulatory mechanisms), rather than from excessive reactivity.

NRAS mutation causes a human autoimmune lymphoproliferative syndrome

The p21 RAS subfamily of small GTPases, including KRAS, HRAS, and NRAS, regulates cell proliferation, cytoskeletal organization, and other signaling networks, and is the most frequent target of activating mutations in cancer. Activating germline mutations of KRAS and HRAS cause severe developmental abnormalities leading to Noonan, cardio-facial-cutaneous, and Costello syndrome, but activating germline mutations of NRAS have not been reported. Autoimmune lymphoproliferative syndrome (ALPS) is the most common genetic disease of lymphocyte apoptosis and causes autoimmunity as well as excessive lymphocyte accumulation, particularly of CD4(-), CD8(-) alphabeta T cells. Mutations in ALPS typically affect CD95 (Fas/APO-1)-mediated apoptosis, one of the extrinsic death pathways involving TNF receptor superfamily proteins, but certain ALPS individuals have no such mutations. We show here that the salient features of ALPS as well as a predisposition to hematological malignancies can be caused by a heterozygous germline Gly13Asp activating mutation of the NRAS oncogene that does not impair CD95-mediated apoptosis. The increase in active, GTP-bound NRAS augments RAF/MEK/ERK signaling, which markedly decreases the proapoptotic protein BIM and attenuates intrinsic, nonreceptor-mediated mitochondrial apoptosis. Thus, germline activating mutations in NRAS differ from other p21 Ras oncoproteins by causing selective immune abnormalities without general developmental defects. Our observations on the effects of NRAS activation indicate that RAS-inactivating drugs, such as farnesyltransferase inhibitors should be examined in human autoimmune and lymphocyte homeostasis disorders.

EBV can protect latently infected B cell lymphomas from death receptor-induced apoptosis

The relationship between EBV infection and sensitivity to death receptor (DR)-induced apoptosis is poorly understood. Using EBV- and EBV+ BJAB cells, we provide the first evidence that EBV can protect latently infected B cell lymphomas from apoptosis triggered through Fas or TRAIL receptors. Caspase 8 activation was impaired and cellular FLIP recruitment was enriched in death-inducing signaling complexes formed in EBV-infected BJAB cells relative to parent BJAB cells. Furthermore, latent membrane protein 1 expression alone could reduce caspase activation and confer partial resistance to DR apoptosis in BJAB cells. This protective effect was dependent on C-terminal activating region 2-driven NF-kappaB activation, which in turn up-regulated cellular FLIP expression in latent membrane protein 1+ BJAB cells. Thus, the ability of latent EBV to block DR apoptosis may help to ensure the survival of host cells during B cell differentiation, and contribute to the development of B cell lymphomas, especially in immunocompromised individuals.

Patient-centred screening for primary immunodeficiency: a multi-stage diagnostic protocol designed for non-immunologists

Efficient early identification of primary immunodeficiency disease (PID) is important for prognosis, but is not an easy task for non-immunologists. The Clinical Working Party of the European Society for Immunodeficiencies (ESID) has composed a multi-stage diagnostic protocol that is based on expert opinion, in order to increase the awareness of PID among doctors working in different fields. The protocol starts from the clinical presentation of the patient; immunological skills are not needed for its use. The multi-stage design allows cost-effective screening for PID within the large pool of potential cases in all hospitals in the early phases, while more expensive tests are reserved for definitive classification in collaboration with an immunologist at a later stage. Although many PIDs present in childhood, others may present at any age. The protocols presented here are therefore aimed at both adult physicians and paediatricians. While designed for use throughout Europe, there will be national differences which may make modification of this generic algorithm necessary.