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Query: UMLS:C0038002 (splenomegaly)
 9,873 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Programmed cell death (or apoptosis) is a physiological process essential to the normal development and homeostatic maintenance of the immune system. The Fas/Apo-1 receptor plays a crucial role in the regulation of apoptosis, as demonstrated by lymphoproliferation in MRL-lpr/lpr mice and by the recently described autoimmune lymphoproliferative syndrome (ALPS) in humans, both of which are due to mutations in the Fas gene. We describe a novel family with ALPS in which three affected siblings carry two distinct missense mutations on both the Fas gene alleles and show lack of Fas-induced apoptosis. The children share common clinical features including splenomegaly and lymphadenopathy, but only one developed severe autoimmune manifestations. In all three siblings, we demonstrated the presence of anergic CD3+CD4-CD8- (double negative, [DN]) T cells; moreover, a chronic lymphocyte activation was found, as demonstrated by the presence of high levels of HLA-DR expression on peripheral CD3+ cells and by the presence of high levels of serum activation markers such as soluble interleukin-2 receptor (slL-2R) and soluble CD30 (sCD30).
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PMID:Missense mutations in the Fas gene resulting in autoimmune lymphoproliferative syndrome: a molecular and immunological analysis. 902 21

Programmed cell death (apoptosis) of activated lymphocytes is critical to immune homeostasis. The cell surface protein Fas (CD95) and its ligand play a pivotal role in regulating lymphocyte apoptosis, and defective expression of either Fas or Fas ligand results in marked over accumulation of mature lymphocytes and autoimmune disease in mice. The results of recent studies suggest that defective lymphocyte apoptosis caused by mutations of the Fas gene can result in a severe autoimmune lymphoproliferative syndrome (ALPS) in humans. To define the clinical, genetic, and immunologic spectrum of ALPS, 9 patients and their families were extensively evaluated with routine clinical studies, lymphocyte phenotyping, genotyping, and in vitro assays for lymphocyte apoptosis. Individual patients were followed up for 3 months to 6 years. ALPS was identified in 9 unrelated children as manifested by moderate to massive splenomegaly and lymphadenopathy, hypergammaglobulinemia, autoimmunity, B-cell lymphocytosis, and the expansion of an unusual population of CD4- CD8- T cells that express the alpha/beta T-cell receptor (TCR). All patients showed defective lymphocyte apoptosis in vitro. Heterozygous mutations of the Fas gene were detected in 8 patients. One ALPS patient lacked a Fas gene mutation. Healthy relatives with Fas mutations were identified in 7 of 8 ALPS kindreds. These relatives also showed in vitro abnormalities of Fas-mediated lymphocyte apoptosis, but clinical features of ALPS were not present in the vast majority of these individuals. ALPS is a unique clinical syndrome in which in vitro abnormalities of lymphocyte apoptosis are associated with abnormal lymphoproliferation and autoimmunity. These findings provide evidence that apoptosis of activated lymphocytes is an important mechanism for maintaining immunologic homeostasis and self-tolerance in humans. Fas gene mutations account for impaired lymphocyte apoptosis in only a subset of patients with ALPS.
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PMID:Clincal, immunologic, and genetic features of an autoimmune lymphoproliferative syndrome associated with abnormal lymphocyte apoptosis. 902 57

Fas (CD95) is a transmembrane molecule that induces programmed cell death (PCD) of lymphocytes. We examined its function in children with chronic thrombocytopenia, serum autoantibodies, and lymphadenopathy and/or splenomegaly. We found that T-cell lines from six of seven patients with this autoimmune/lymphoproliferative disease (ALD) were relatively resistant to PCD induced by monoclonal antibodies to Fas. By contrast, Fas function was normal in control patients with typical chronic idiopathic thrombocytopenic purpura (ITP) without lymphadenopathy. The defect was not due to decreased Fas expression, nor to over-production of soluble forms of Fas. Moreover, it specifically involved the Fas system because PCD was induced in the normal way by methylprednisolone. Complementary DNA sequencing of the Fas gene did not identify any causal mutation in patients with ALD. This distinguished them from patients with the human autoimmune lymphoproliferative syndrome (ALPS), who carry mutations of the Fas gene. Moreover, patients with ALD did not show the peripheral expansion of CD4/CD8 double-negative T cells that characterizes the ALPS phenotype. Fas signaling involves activation of a sphingomyelinase-catalyzing production of ceramide. We found that ceramide-induced PCD was defective in patients with ALD and not in patients with typical chronic ITP. These data suggest that the ALD patient defect involves the Fas signaling pathway downstream from the sphingomyelinase and that Fas gene mutations and double-negative T-cell expansion are not the only signs of a defective Fas system.
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PMID:Deficiency of the Fas apoptosis pathway without Fas gene mutations in pediatric patients with autoimmunity/lymphoproliferation. 910 7

The autoimmune lymphoproliferative syndrome (ALPS) affords novel insights into the mechanisms that regulate lymphocyte homeostasis and underlie the development of autoimmunity. This syndrome arises early in childhood in persons who inherit mutations in genes that mediate apoptosis, or programmed cell death. The timely deletion of lymphocytes is a way to prevent their accumulation and the persistence of cells that can react against the body's own antigens. In ALPS, defective lymphocyte apoptosis permits chronic, nonmalignant adenopathy and splenomegaly; the survival of normally uncommon "double-negative" CD3+ CD4- CD8- T cells; and the development of autoimmune disease. Most cases of ALPS involve heterozygous mutations in the lymphocyte surface protein Fas that impair a major apoptotic pathway. Detailed immunologic investigations of the cellular and cytokine profiles in ALPS show a prominent skewing toward a T-helper 2 phenotype; this provides a rational explanation for the humoral autoimmunity typical of patients with ALPS. Prospective evaluations of 26 patients and their families show an ever-expanding spectrum of ALPS and its major complications: hypersplenism, autoimmune hemolytic anemia, thrombocytopenia, and neutropenia. Defective apoptosis may also contribute to a heightened risk for lymphoma.
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PMID:An inherited disorder of lymphocyte apoptosis: the autoimmune lymphoproliferative syndrome. 1018 30

Apoptosis via CD95 and its ligand is an important mechanism that prevents uncontrolled proliferation of activated lymphocytes and regulates lymphocyte homeostasis. The apoptosis receptor CD95 is a transmembrane protein with an intracellular domain well conserved between CD95 and tumor necrosis factor receptor I, another apoptosis-inducing protein. Because of its functional importance, this domain was designated the death domain. We describe the molecular analysis of the CD95 death domain in a family with autoimmune lymphoproliferative syndrome (Canale-Smith syndrome), T-cell lymphoma, and Hodgkin's disease. A functional defect in apoptosis was detected in cells from the index patient, a 5-year-old girl suffering from Canale-Smith syndrome and a T-cell lymphoma, as well as in her father, who had a history of splenomegaly and mild hemolysis, and her paternal uncle who had been cured of Hodgkin's disease (HD). Expansion of double-negative T cells (CD4-CD8-) was only seen in the index patient. All family members with a functional defect in apoptosis were heterozygous for a point mutation in the death domain of CD95 (A1009G, E256G). We conclude that, within the same family, a defect in apoptosis due to a mutation in the CD95 death domain can be associated with diverse clinical phenotypes, including mild, reversible symptoms and different malignancies.
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PMID:Defective apoptosis due to a point mutation in the death domain of CD95 associated with autoimmune lymphoproliferative syndrome, T-cell lymphoma, and Hodgkin's disease. 1034 Apr 3

Autoimmune lymphoproliferative disease (ALD) is a rare familial disorder. Clinical and laboratory features of this disease include a generalized lymphadenopathy, splenomegaly, increased levels of circulating CD3+ with low levels of CD4+, CD8+ T-cells, and autoimmune phenomena, characteristics that the autoimmune lymphoproliferative syndrome (ALPS) have in common. Treatment usually consists of different supportive therapies. We report on the case of a young man affected by ALD who became resistant to steroids and was unresponsive to cyclosporine. Nevertheless, he was successfully treated with interferon (IFN)-alpha, resulting in a long-lasting, clinically complete remission.
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PMID:Interferon-alpha activity in a case of severe autoimmune lymphoproliferative disease. 1123 77

FAS germline mutations have been associated with the development of autoimmune lymphoproliferative syndrome (ALPS). Occurrence of Hodgkin lymphoma (HL) has been reported in 2 families with ALPS. In both families an uncle of the index patient developed HL. A 15-year-old boy with autoimmune thrombopenia, lymphadenopathy, and splenomegaly for 6 years was studied. In an axillary lymph node biopsy nodular lymphocyte predominant (NLP) HL was diagnosed; in the areas between the nodules a proliferation of double-negative blastic T cells were present, suggestive of ALPS. Analysis for the presence of a FAS gene mutation using the denaturing gradient gel electrophoresis technique indicated a mutation in exon 9. Direct sequence analysis revealed a mutation causing a substitution of arginine with glutamine at codon 234. Because ALPS and NLP HL are both highly infrequent conditions, the occurrence in at least 3 families suggests a causative relationship between germline FAS gene mutations and NLP HL.
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PMID:Germline FAS gene mutation in a case of ALPS and NLP Hodgkin lymphoma. 1183 May 7

A boy of Caucasian origin with a new subtype of autoimmune lymphoproliferative syndrome (ALPS) is described. The clinical picture was dominated by chronic noninfectious lymphadenopathy, splenomegaly, and recurrent bacterial infections. At the age of 6 the patient died of pneumococcal meningitis. Laboratory investigation disclosed impaired apoptosis in both B- and T-lymphocyte subsets and expanded populations of CD3+CD4-CD8- T lymphocytes. Furthermore, marked dysregulation of humoral immune responses with transient expansion of monoclonal B cells, corresponding monoclonal gammopathy, and the presence of autoantibodies was found. Functional and molecular analysis revealed that Fas protein expression was normal, a mutation in the Fas gene was not found. Moreover, transcription of the downstream effector caspase-10 was unremarkable. This patient is unique compared to previously described patients as severe humoral immunodeficiency and monoclonal gammopathy are usually not described in patients with ALPS. This case points out the important role of apoptosis in regulating the degree of humoral immune responses at a clonal level in humans and gives further evidence for the phenotypic diversity of ALPS.
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PMID:Autoimmune lymphoproliferative syndrome associated with severe humoral immunodeficiency and monoclonal gammopathy. 1210 64

The discovery of an unusual T-cell subset characterized by the expression of the alpha/beta T-cell receptor without expression of either CD4 or CD8 [alpha/beta-double-negative T cells (alpha/beta-DNTCs)] provided critical insights in the evaluation of a "new" lymphoproliferative disorder known as autoimmune lymphoproliferative syndrome (ALPS). ALPS is a disorder of defective Fas-mediated lymphocyte apoptosis, manifested by accumulation of alpha/beta-DNTCs and other lymphocyte subsets, leading to lymphadenopathy and splenomegaly, autoimmunity, and an increased risk of lymphoma. The expanded population of alpha/beta-DNTCs from ALPS patients has a remarkable uniform phenotype that is for the most part similar to alpha/beta-DNTCs from mice with defective Fas (lpr) or Fas ligand (gld). This is in contrast to the minor alpha/beta-DNTC compartment in healthy individuals that contains multiple, immunophenotypically distinct subpopulations. Current data indicate that alpha/beta-DNTCs from ALPS patients are derived from cytotoxic CD8(+) T cells, chronically activated in vivo but anergic in vitro. Their anergic state may be related to persistent modifications of O-linked carbohydrates on cell surface molecules, such as CD43 and CD45, as well as to the increased presence of interleukin-10. Although largely consistent with a model of (linear) CD8(+) cytotoxic T-cell differentiation, the expression patterns of certain surface molecules, such as CD27 and CD28, are not consistent with this model. This may be the result of the perturbed homeostasis of lymphocytes in ALPS, thereby revealing pathways of differentiation and immunophenotypes, including phenotypes pertaining to cell surface glycosylation that are hidden from view in healthy individuals.
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PMID:A composite picture of TcR alpha/beta(+) CD4(-)CD8(-) T Cells (alpha/beta-DNTCs) in humans with autoimmune lymphoproliferative syndrome. 1213 44

Apoptosis is a form of programmed cell death that is controlled by aspartate-specific cysteine proteases called caspases. In the immune system, apoptosis counters the proliferation of lymphocytes to achieve a homeostatic balance, which allows potent responses to pathogens but avoids autoimmunity. The CD95 (Fas, Apo-1) receptor triggers lymphocyte apoptosis by recruiting Fas-associated death domain (FADD), caspase-8 and caspase-10 proteins into a death-inducing signalling complex. Heterozygous mutations in CD95, CD95 ligand or caspase-10 underlie most cases of autoimmune lymphoproliferative syndrome (ALPS), a human disorder that is characterized by defective lymphocyte apoptosis, lymphadenopathy, splenomegaly and autoimmunity. Mutations in caspase-8 have not been described in ALPS, and homozygous caspase-8 deficiency causes embryonic lethality in mice. Here we describe a human kindred with an inherited genetic deficiency of caspase-8. Homozygous individuals manifest defective lymphocyte apoptosis and homeostasis but, unlike individuals affected with ALPS, also have defects in their activation of T lymphocytes, B lymphocytes and natural killer cells, which leads to immunodeficiency. Thus, caspase-8 deficiency in humans is compatible with normal development and shows that caspase-8 has a postnatal role in immune activation of naive lymphocytes.
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PMID:Pleiotropic defects in lymphocyte activation caused by caspase-8 mutations lead to human immunodeficiency. 1235 64


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