Humanized anti-interleukin 6 receptor antibody induced long-term remission in a patient with life-threatening refractory autoimmune hemolytic anemia.

Refractory autoimmune hemolytic anemia (AIHA) is associated with considerable rates of mortality. Interleukin 6 (IL-6) has been reported to play a role in the pathogenesis of AIHA. This report describes a patient with AIHA who was successfully treated with a humanized anti-human IL-6 receptor (IL-6R) monoclonal antibody (MoAb). He had experienced life-threatening AIHA and had received conventional therapy with corticosteroids, azathioprine, cyclophosphamide, cyclosporin A, melphalan, plasma exchange, and irradiation to his spleen. However, the patient's symptoms and laboratory data did not show a sufficient improvement. Because his serum IL-6 level was elevated, we attempted to block IL-6 signaling by using a humanized anti-IL-6R MoAb, MRA. With 8 mg/kg of MRA administration every 2 weeks, the serum hemoglobin level gradually increased and normalized within 4 months. After 2 years of MRA treatment, the disease activity was well controlled without adverse reactions. Anti-IL-6R MoAb can be a novel and effective therapeutic agent for AIHA.