Thrombotic thrombocytopenic purpura treated with high-dose intravenous gamma globulin. Plasma infusion and/or plasma exchange has become standard therapy in the treatment of thrombotic thrombocytopenic purpura (TTP). The management of patients in whom such primary therapy fails is difficult and uncertain. We have described a patient who obtained a sustained remission with the use of high-dose IV gamma globulin after an initial response to aggressive plasma exchange was followed by prompt relapse. Our case and others suggest that high-dose IV IgG may induce remission in patients with TTP who do not respond to standard plasma infusion and/or exchange. 