Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is evidence indicating that autoreactive B cells constitute a substantial part of the B cell repertoire. This autoreactive repertoire secretes the so-called natural autoantibodies characterized by their broad reactivity mainly directed against well-conserved public epitopes. Their germinal origin is suggested by their early appearance during ontogeny, their expression of cross-reactive idiotopes, and structural studies of their sequence. As for the physiological role of the repertoire, it may play a major role as a first barrier of defense. It is presently unknown whether these polyreactive B cells could constitute a pre-immune template which, through an antigen-driven process, may be involved in the production of immune high-affinity antibodies. This autoreactive B cell repertoire frequently undergoes malignant transformation, although there is controversy concerning the reasons accounting for this. It has been postulated that the continuous challenge of this autoreactive repertoire by self-antigens could create propitious conditions for malignant transformation to occur. However, this hypothesis still needs to be substantiated. Chronic lymphocytic leukemia (CLL), the most frequent form of leukemia in western countries, is characterized by constant expression of the CD5 marker and low expression of surface membrane immunoglobulin (Ig) in B lymphocytes. CLL B lymphocyte is frequently committed for natural autoantibody secretion. Despite expressing the Epstein-Barr virus (EBV) receptor CLL B cells cannot be infected by the EBV virus, they overexpress the bcl-2 protein and they are unable to adequately respond when stimulated through the B cell receptor pathway. Autoimmune-associated phenomena are frequently observed in B-cell CLL. These autotoxic manifestations are mainly directed against hematopoietic cells. In most cases, autoantibodies against red blood cells are warm reactive polyclonal IgG. Immune thrombocytopenia is observed in about 2% of cases, but higher frequencies of increased platelet associated Igs have been reported. Pure red cell aplasia and autoantibodies against neutrophils are only rarely observed. This pattern is similar to that observed in primary immunodeficiency syndromes, in which immune thrombocytopenia, autoimmune hemolytic anemia, and pure red cell aplasia are frequently observed. The potential role of T cell defects in inducing autoimmune complications in B-cell CLL has been stressed by recent publications showing increased frequency of autoimmune hemolytic anemia in patients treated with purine nucleoside analogues. However, evidence is presently scarce concerning a functional impairment of T cells after administration of these drugs.
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PMID:Basic biology of autoimmune phenomena in chronic lymphocytic leukemia. 948 25

Hematological abnormalities are frequent among human immunodeficiency virus (HIV)-infected patients and may be directly attributable to the virus or may be caused by opportunistic infections, neoplasms or drugs that cause bone marrow suppression or hemolysis. Pure red cell aplasia (PRCA) is an uncommon hematological disorder that causes anemia. We report a 37-year-old male with HIV infection who developed PRCA 6 weeks after commencing Zidovudine and recovered following cessation of the drug. This is the first case of Zidovudine-induced PRCA reported from the Indian subcontinent.
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PMID:Zidovudine-induced reversible pure red cell aplasia. 2087 73

Anaemia is common among human immunodeficiency virus (HIV)-infected patients. It may be directly attributable to the virus or may be caused by opportunistic infections, neoplasms or drugs that cause either bone marrow suppression or haemolysis. Pure red cell aplasia (PRCA) is an uncommon haematological disorder that causes severe transfusion dependant anaemia. We report a 36 year-old female with HIV infection who developed anaemia which did not improve even after discontinuing the offending drug, namely Zidovudine. Routine investigations were unhelpful but her bone marrow study was consistent with pure red cell aplasia. She showed dramatic improvement with steroids with subsequent transfusion independence.
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PMID:Refractory anaemia in an immunocompromised patient--what is it? 2477 15

Thymoma is an uncommon slowly growing neoplasm. It usually presents with paraneoplastic syndromes including the immunodeficiency syndrome called Good syndrome and hematological disorders. Pure red cell aplasia is a well-recognized complication of thymoma, and aplastic anemia is very rare in association with GS. We report a case of GS in a heavily treated patient with stage IV thymoma associated with a pure red cell aplasia and an amegakaryocytic thrombocytopenia that evolved into an AA and provide an up-to-date review of the relevant literature. This is the first case of the association of GS and AA with the coexistence of a heavily treated stage IV thymoma. The fatal outcome was not related to the progression of the thymoma, but rather to the severe infectious complications. The combination of lymphopenia and hypogammaglobulinemia typical of GS, coupled to the neutropenia, caused by bone marrow failure, was the main predisposing factor for the unfavourable outcome.
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PMID:Aplastic Anemia and Good Syndrome in a Heavily Treated Stage IV Thymoma Patient: A Case Report and Review of the Literature. 3178 23