The role of rituximab in the management of patients with acquired thrombotic thrombocytopenic purpura.

A 40-year-old obese black woman developed abdominal pain with progressive generalized weakness over several days. Physical examination was normal except for several small bruises on her extremities. Laboratory data revealed the following: hemoglobin, 5.0 g/dL; platelet count, 4000/mL; creatinine, 0.8 mg/dL; lactate dehydrogenase, 1364 U/L. Peripheral blood smear revealed many schistocytes. Acquired thrombotic thrombocytopenic purpura (TTP) was diagnosed, and treatment was initiated with daily plasma exchange (PEX) and prednisone (1 mg/kg/day). The subsequent report of ADAMTS13 (a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13) activity <5% with an inhibitor titer of 3 Bethesda Units supported the diagnosis of TTP. After 6 days of PEX, she was asymptomatic, and her platelet count had been normal for2days, reaching178 000/mL;PEXwas stopped.