Anti-CD20 chimeric monoclonal antibody treatment of refractory immune-mediated thrombocytopenia in a patient with chronic graft-versus-host disease

Background: Autoimmune thrombocytopenia in chronic graft-versus-host diseas e may represent an instance of B-cell dysregulation leading to clinical dis ease. Objective: To attempt to treat refractory immune-mediated thrombocytopenia in a patient with chronic graft-versus-host disease by using anti-CD20 chim eric monoclonal antibody. Design: Case report. Setting: Academic medical center. Patient: A patient with chronic graft-versus-host disease after allogeneic peripheral blood stem-cell transplantation who had severe refractory immune -mediated thrombocytopenia. Intervention: Weekly Infusion of rituximab, 375 mg/m(2), for 4 weeks. Measurements: Platelet count, CD3(+) cell count, and CD19(+) cell count. Results: Rituximab therapy resulted in marked depletion of B cells in the p eripheral blood and decreased levels of platelet-associated antibody. The i ncrease in platelet count persisted despite tapering and discontinuation of immunosuppressive therapy for chronic graft-versus-host disease. Conclusion: The efficacy of rituximab for the treatment of immune-mediated thrombocytopenia suggests that this drug may have activity in other autoimm une diseases or chronic graft-versus-host disease.