Successful anti-CD20 monoclonal antibody treatment of severe autoimmune hemolytic anemia due to warm reactive IgM autoantibody in a child with common variable immunodeficiency.

Autoimmune hemolytic anemia due to warm reactive IgM autoantibodies is unusual, severe, and often fails to respond to standard immunosuppressive therapies in both adults and children. A 6-year-old girl with common variable immunodeficiency had longstanding steroid dependent, splenectomy-unresponsive, warm IgM autoantibody-mediated autoimmune hemolytic anemia. Rituximab, a monoclonal antibody directed against CD20 antigen, was used to deplete B lymphocytes and reduce autoantibody production. She received a total of six doses of rituximab (375 mg/m2). Therapy was well tolerated, and B-lymphocytes were effectively depleted from the peripheral blood. The patient was completely tapered off glucocorticoids. The patient has remained off immunosuppressive agents for 16 months despite the return of B lymphocytes to the peripheral circulation. She continues to require IVIG. Early treatment with rituximab might be an option for patients with warm reactive IgM autoantibody-mediated autoimmune hemolytic anemia not responding to other treatments or experiencing untoward side effects from those treatments.