title: Autoimmune and alloimmune phenomena in patients with aplastic anemia: cytotoxicity against autologous lymphocytes and lymphocytes from HLA identical siblings.
abstract: We have studied peripheral blood lymphocytes of 117 patients with severe aplastic anemia and 237 healthy individuals for reactivity against autologous lymphocytes and/or lymphocytes from HLA-identical siblings using a 51Cr release assay. Lymphocytes from 29% of the patients exhibited reactivity against their own lymphocytes, while only 3% of lymphocytes from normal individuals showed such reactivity. Lymphocytes from 49% of the patients showed reactivity against lymphocytes from their HLA-identical siblings compared to 4% of normal individuals. Correlation existed between allogeneic and autologous reactivities (p < 0.001), suggesting a common pathway for cytotoxicity. Both reactivities showed an association with extremely low granulocyte counts (p < 0.01) and an inability of the patient's mononulcear cells to stimulate in allogeneic mixed leukocyte culture (p < 0.05) as well as an inverse correlation with time from diagnosis (p < 0.001). At least two explanations exist for the transfusion-independent autologous and allogeneic cytotoxicities: (1) they could be epiphenomena secondary to the stem cell defect, such as the loss of a cell that suppresses (or regulates) naturally occurring cytotoxic cells, or (2) they may be involved in the cause of the disease.
mesh_terms: D000741:Anemia, Aplastic / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D006680:HLA Antigens / Q000276:immunology*; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology*
chemical_list: D006680:HLA Antigens