Successful treatment of severe thrombotic thrombocytopenic purpura with the monoclonal antibody rituximab.

The only established treatment for patients with thrombotic thrombocytopenic purpura (TTP) is plasma exchange against fresh frozen plasma. For cases refractory to plasma exchange, no generally treatment schedule exists. One option is immunosuppressive therapy with corticosteroids and vincristine. Rituximab is a chimeric monoclonal antibody directed against the CD20 antigen, and it has been successfully used in B-cell malignancies and is being investigated in autoimmune diseases. Its efficacy in TTP has not yet been determined. We report two female patients with severe TTP refractory to multiple courses of plasmapheresis, high-dose steroid treatment, and vincristine who responded after adding rituximab while continuing plasmapheresis.