Severe Evans's syndrome secondary to interleukin-2 therapy: treatment with chimeric monoclonal anti-CD20 antibody.

Interleukin-2 (IL-2) acts by increasing the efficiency of the immune system to exert a tumoricidal effect. Although it is well known that immune stimulation with IL-2 plays a role in unmasking autoimmune phenomena such as autoimmune thyroiditis, hematological effects such as anemia and thrombocytopenia are more frequently due to toxic non-immune mechanisms. We describe a patient who developed severe Evans's syndrome [autoimmune hemolytic anemia (AHA) and immune thrombocytopenic purpura (ITP)] secondary to IL-2 therapy. ITP was refractory to multiple treatment modalities including steroids and splenectomy. ITP and AHA were initially managed with intravenous gamma globulin therapy and frequent blood transfusions, respectively. Ultimately, immunosuppressive therapy with cyclophosphamide and chimeric monoclonal anti-CD20 antibody (rituximab) were successful in inducing complete remission of Evans's syndrome.