Successful Treatment of Refractory Idiopathic Thrombocytopenic Purpura and Neutropenia with the Monoclonal Antibody, Rituximab

We describe a 22-year-old male with idiopathic autoimmune thrombocytopenia whose diagnosis was made at age of eight. He underwent splenectomy at age ten and ITP recurred at age 21 with episodes of infection and severe neutropenia (absolute count around 170/μl). He showed no response to immunoglobulin, corticosteroids, danazol, cyclosporine and azathioprine. Anti-CD20 antibody was administered at a dose of 375 mg/m 2 once a week for 2 weeks. After the second infusion of rituximab, the platelet count increased from 4,000 to 516,000/mm 3 and neutrophils count raised from 180 to 545/mm 3 . The response improvement persisted during follow up for 9 months (neutrophil count 4,390/mm 3 ). This observation indicates that B-cells may play a central role in the pathogenesis of ITN. Anti-CD20 antibody therapy may be an efficient treatment for the patients with chronic or recurrent ITN.