Successful Treatment of Refractory Thrombotic Thrombocytopenic Purpura with Rituximab, a Monoclonal Antibody: a Case Report

Thrombotic thrombocytopenic purpura (TTP) is mostly attributed to the presence of an autoantibody against ADAMTS-۱۳, a metalloprotease that degrades ultralarge von Willebrand protein multimers. Accumulation of vWF multimers and systemic platelet aggregation lead to microangiopathic thrombosis, hemolytic anemia, and end-organ ischemia. Most patients respond to therapeutic plasma exchange (TPE), which replaces the missing protease and removes the circulating inhibitor. However, some cases (۱۰%-۲۰%) might not respond to TPE alone, and, therefore, interest has been aroused to use the novel immunosuppressive anti-B-cell antibody, rituximab. We report a ۱۲-year old male patient with severeTTP refractory to multiple courses of plasmapheresis and high-dose steroid treatment in whom the combined use of daily plasma exchange and rituximab was associated with clinical resolution of active TTP, and we discuss the benefits and possible timing of combined therapy. Retuximeb used with plasma exchange can lead to sustained clinical remission in patients with refractory autoimmune TTP.