title: Autoimmune thrombocytopenia in sarcoidosis.
abstract: Severe thrombocytopenia and splenomegaly developed in a young man with sarcoidosis. Platelet-associated immunoglobulin (IgG) was strongly positive, and platelet survival studies revealed a half-life of five and a half hours. Treatment with prednisone and vincristine led to a rise in the platelet count to 100,000/mm3 after two months with no change in the splenomegaly. Five months later, when the platelet count was normal, the level of platelet-associated IgG had fallen to normal. Repeated platelet survival studies showed an initial half-life of three hours with a second half-life of two days, associated with accumulation in the spleen. Although there was evidence for splenic sequestration of platelets, the dominant mechanism of thrombocytopenia appeared to be antibody-mediated destruction, analogous to that seen in idiopathic autoimmune thrombocytopenic purpura and responsive to immunosuppressive therapy.
mesh_terms: D000328:Adult; D001327:Autoimmune Diseases / Q000209:etiology / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D010976:Platelet Count; D011241:Prednisone / Q000627:therapeutic use; D012507:Sarcoidosis / Q000150:complications / Q000276:immunology*; D013163:Splenomegaly / Q000276:immunology; D013921:Thrombocytopenia / Q000188:drug therapy / Q000209:etiology / Q000276:immunology*; D014750:Vincristine / Q000627:therapeutic use
chemical_list: D007074:Immunoglobulin G; D014750:Vincristine; D011241:Prednisone