Elevated platelet-associated IgG in thrombotic thrombocytopenic purpura.

A 41-year--old woman with thrombotic thrombocytopenic purpura (TTP) was treated with prednisone and splenectomy with complete recovery from her illness. Analysis of the patient's platelets for immunoglobulins showed abnormally elevated levels in the range of those seen in thrombocytopenic patients with systemic lupus erythematosus, immune vasculitis, and infectious mononucleosis. This finding is consistent with the concept that the immune system may play a role in the pathogenesis of TTP.