[Three cases of chronic relapsing thrombotic thrombocytopenic purpura]

We experienced three cases of thrombotic thrombocytopenic purpura (TTP) with repeated relapse and remission, in which the relapse was improved by plasma infusion. One case has continued remission after one relapse. The second case went into remission after several relapses, which were induced by viral infection and pregnancy. The third case has shown repeated chronic relapses over 7 years without any inducing factors. The course of TTP relapse commenced with thrombocytopenia accompanied by microangiopathic hemolytic anemia and neurological disturbances developed over 1-4 weeks. The volume plasma needed for recovery gradually increased with time from the start of relapse. These relapses were unable to be prevented by oral administration of antiplatelet agents (aspirin and dipyridamole).