Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019214 (hepatosplenomegaly)
 4,408 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inherited mutations of the Fas/Apo1/CD95 gene, a cell-surface receptor involved in cell death signaling and in the control of self-reactivity, characterize the recently identified autoimmune lymphoproliferative syndromes. A patient with type 2 autoimmune hepatitis with the immunologic and genetic features of autoimmune lymphoproliferative syndrome is described. The clinical picture was dominated by liver disease with hepatosplenomegaly and positivity for anti-liver-kidney microsome 1 and anti-liver-cytosol 1 antibodies. A marked increase in CD3+CD4-CD8-T lymphocytes and inherited mutations in Fas alleles that led to the expression of a soluble form of the protein were also found. Fas-mediated apoptosis was deficient in the patient as it was in her mother and her sister, who carried the same allele 2 mutation. This observation links type 2 autoimmune hepatitis, an organ-specific disease, with a genetically determined defect in peripheral tolerance control.
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PMID:Fas/Apo1 mutations and autoimmune lymphoproliferative syndrome in a patient with type 2 autoimmune hepatitis. 961 60

Omenn's syndrome (OS) is characterized by erythrodermia, hepatosplenomegaly, lymphadenopathy, hypereosinophilia and elevated IgE levels associated with increased susceptibility to severe infections. Peripheral blood T cells, though usually present in normal number, show an activated phenotype (including an increased expression of CD95/Fas), a Th2 pattern of cytokine secretion and defective proliferative response to mitogens. In this report, we demonstrate that T cells from patients with OS undergo an excessive cell death in vitro resulting from two mechanisms. First, a substantial number of peripheral blood lymphocytes from OS patients die in unstimulated cultures (p = 0.009 vs. healthy controls). This spontaneous apoptosis is associated with reduced expression of bcl-2 gene product (p < 0.05) and can be prevented by addition of interleukin (IL)-2 (which also prevents down-modulation of bcl-2), while is independent from CD95 signaling. Second, lymphocytes from OS patients are highly susceptible to activation-induced cell death (AICD) induced with mitogens. This mechanism is largely independent from IL-2, while it can be significantly inhibited blocking CD95 with an IgG2b monoclonal antibody (mAb). The dependence of AICD from signals transduced via CD95 was confirmed showing that cross-linking CD95 with an IgM mAb induces a higher cell death in purified CD4+ CD45R0+ cells from OS patients than in controls (comparable for CD95 expression). Both mechanisms of cell death observed in this study result from lymphocyte hyperactivation occurring in vivo in these patients and may contribute to functional T cell defects of OS.
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PMID:In vitro cell death of activated lymphocytes in Omenn's syndrome. 939 97

The FAS (CD95/APO-1) receptor and its ligand play an important role in the initiation of apoptosis under many physiologic conditions. Loss of function mutations of the FAS gene have been described in lpr mice and in humans with autoimmune phenomena, recurrent lymphadenopathies, and hepatosplenomegaly. This syndrome is now called autoimmune lymphoproliferative syndrome type I (ALPS I). Recently, patients with similar clinical symptoms due to a functional FAS deficiency without FAS gene mutations have been distinguished. This disease has been termed autoimmune lymphoproliferative syndrome type II (ALPS II) or autoimmune lymphoproliferative disease (ALD). This report is the first description of the lymph node pathology and immunohistochemistry in a patient with ALPS II. After recurrent bacterial infections, a 4-year-old child developed cervical giant lymphadenopathy suggesting lymphoma. Lymph node histology resembled the findings in Epstein Barr virus-associated posttransplant atypical lymphoproliferations. Confluent sheets of immunoblasts, however, showed a monoclonal expression of IgG/lambda and a monoclonal rearrangement of the JH chain. The same clone was also present in the peripheral blood. Although high-grade lymphoma could not be excluded, the patient's parents insisted on the patient's leaving the hospital with only antibiotic treatment. Surprisingly, the giant lymphadenopathy completely resolved within 7 weeks, and the clone was no longer detectable in the peripheral blood. Twelve months later the patient was still free from lymphoma and was doing well. Retrospectively, transient monoclonal B-cell populations could be identified in an archival frozen blood sample taken when the patient was 3 years old. Increased FAS-independent spontaneous apoptosis was a feature of the patient's lymphocytes and could be the molecular basis for self-elimination of B-cell clones. We conclude that the diagnosis of a FAS-FAS-L deficiency should be considered in children with an otherwise unexplained atypical lymphoproliferation and that a diagnosis of lymphoma in patients with functional FAS deficiency should be made with considerable reservation.
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PMID:Reversible monoclonal lymphadenopathy in autoimmune lymphoproliferative syndrome with functional FAS (CD95/APO-1) deficiency. 1040 7

Most humans with autoimmune lymphoproliferative syndrome (ALPS) carry heterozygous dominant mutations in one allele of the gene encoding Fas/APO-1/CD95. ALPS patients, like Fas-deficient MRL lpr/lpr mice, have lymphoproliferation, autoimmunity, increased CD4(-)/CD8(-) T lymphocytes, and apoptosis defects. Consistent with the phenotypic variability of lpr/lpr mice of different background strains, human genetic studies indicate that a Fas mutation is insufficient to induce ALPS in all mutation carriers. To investigate the dominant function of human Fas mutations and the additional genetic factor(s) involved in the development of ALPS, we generated transgenic mice expressing, in addition to endogenous Fas, mouse Fas molecules bearing mutations in the intracellular death domain corresponding to mutations identified in ALPS patients. Transgenic mice developed mild features of ALPS, including hepatosplenomegaly, elevated proportions of lymphocytes in spleen and lymph nodes, apoptotic defects, and hepatic lymphocytic infiltrates. Therefore defective murine Fas proteins act in a dominant manner to impair apoptosis of activated lymphocytes and disrupt lymphocyte homeostasis. The influence of genetic background on phenotype was studied by comparing transgenic mice on FVB/N and (FVB/N x MRL) backgrounds with syngenetic control mice and with MRL and MRL lpr/lpr mice. While expression of transgenic mutant Fas contributed mainly to hepatosplenomegaly and accumulation of lymphocytes, MRL background genes played a major role in the production of autoantibodies and elevated serum immunoglobulin levels. Moreover, compared to FVB/N (+/+) mice, a substantial Fas-specific apoptotic defect was found in MRL (+/+) mice, suggesting a mechanism for the known tendency of this strain to develop autoimmunity.
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PMID:Expression in transgenic mice of dominant interfering Fas mutations: a model for human autoimmune lymphoproliferative syndrome. 1049 9

Patients with autoimmune lymphoproliferative syndrome (ALPS) have defective lymphocyte apoptosis with increased risk for lymphoid malignancies. Herein, we report a patient with ALPS who developed histiocytic sarcoma in a background of sinus histiocytosis and massive lymphadenopathy or Rosai- Dorfman disease. This patient had documented ALPS type Ia with a germline missense mutation in exon 9 of the TNFRSF6 gene (973 A>T, D244V) encoding Fas (CD95/Apo-1). He presented at 10 months with hepatosplenomegaly and autoimmune hemolytic anemia and was diagnosed with ALPS. At the age of 6 (1/2) years, he developed classic Hodgkin lymphoma which was treated using standard chemotherapy. Two years later, a biopsy of a positron emission tomography-positive axillary node showed features of ALPS and focal involvement by sinus histiocytosis and massive lymphadenopathy. Thereafter, the patient continued to have continued lymphadenopathy and progressive splenomegaly, leading to exploratory surgery at the age of 13 years for suspicion of lymphoma. Para-abdominal nodes revealed sheets of malignant- looking histiocytes with increased mitotic activity and areas of necrosis, indicative of histiocytic sarcoma. Spleen and lymph nodes also showed involvement by Rosai-Dorfman disease. Both components had an identical phenotype of S-100+/CD68+/ CD163+. The occurrence of malignancies involving 2 separate hematopoietic lineages in ALPS has not been reported earlier. Given the central role of defective Fas signaling in ALPS, histiocytes may be yet another lineage at risk for neoplastic transformation secondary to a block in apoptosis.
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PMID:Development of disseminated histiocytic sarcoma in a patient with autoimmune lymphoproliferative syndrome and associated Rosai-Dorfman disease. 2021 76