Frequently relapsing thrombotic thrombocytopenic purpura treated with cytotoxic immunosuppressive therapy

Background and Objectives. Treatment of thrombotic thrombocytopenic purpura (TTP) with plasma exchange has reduced mortality rates from 90% in untreat ed cases to less than 20%. Despite plasma exchange, relapses may occur in a s many as 40% of cases. Multiple relapses occur in a minority but pose a si gnificant therapeutic challenge. Recent evidence supports the presence of a n autoantibody which inhibits proteolysis of von Willebrand factor (vWF) in active ITP, allowing large multimers of vWF to form and promote platelet a ggregation. Additional evidence suggests autoantibodies activate capillary endothelium and promote platelet aggregation in the microcirculation. Immun osuppression, thus, has a biologically plausible role in TTP We describe th ree consecutive cases of relapsing TTP treated with cytotoxic therapy to hi ghlight the potential role of immunosuppression, Design and Methods. Cytotoxic immunosuppressive therapy with either cycloph osphamide or azathioprine was used in three consecutive patients with frequ ently relapsing TTP Results. All three patients have maintained remissions of 8 to 10 months wi thout recurrence. Interpretation and Conclusions. Cytotoxic immunosuppressive therapy may hav e a role in inducing long-term remissions in recurrent TTP (C) 2001, Ferrat a Storti Foundation.