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)

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