New treatment options for immune-mediated hematological disorders

Treatment Options for Primary Autoimmune Hemolytic Anemia: A Short Comprehensive Review

Until now, treatment of primary autoimmune hemolytic anemia of the warm type (wAIHA) is primarily based on immunosuppression. However, many patients do not respond adequately to treatment, and treated patients may develop severe side effects due to uncontrolled, mixed and/or long-lasting immunosuppression. Unfortunately, the newly used therapeutic monoclonal antibodies are unspecific and remain frequently ineffective. Thus, development of a specific therapy for AIHA is necessary. The ideal therapy would be the identification and elimination of the causative origin of autoimmunization and/or the correction or reprogramming of the dysregulated immune components. Blood transfusion is the most rapidly effective measure for patients who develop or may develop hypoxic anemia. Although some effort has been made to guide physicians on how to adequately treat patients with AIHA, a number of individual aspects should be considered prior to treatment. Based on my serological and clinical experience and the analysis of evidence-based studies, we remain far from any optimized therapeutic measures for all AIHA patients. Today, the old standard therapy using controlled steroid administration, with or without azathioprine or cyclophosphamide, is, when complemented with erythropoiesis-stimulating agents, still the most effective therapy in wAIHA. Rituximab or other monoclonal antibodies may be used instead of splenectomy in therapy-refractory patients.

Rituximab in autoimmune hematologic diseases: not just a matter of B cells

Rituximab, a chimeric monoclonal antibody that depletes B cells by binding to the CD20 cell-surface antigen, has been investigated extensively in autoimmune disorders. Following the encouraging results in immune thrombocytopenia (ITP), the use of this agent was explored in other autoimmune hematologic diseases, most notably autoimmune hemolytic anemia (AIHA) and thrombotic thrombocytopenic purpura (TTP), characterized by the presence of pathogenetic autoantibodies. Although randomized clinical trials are lacking, the cumulative data would suggest that rituximab has a beneficial role in their treatment. Response to B-cell-depleting therapy is actually associated with a significant decrease of circulating autoantibodies. However, several lines of evidence indicate that the T-cell compartment may also be modulated by these interventions. The doses and the duration of rituximab treatment in patients with autoimmune diseases are still unclear. The incidence of severe side effects is low but not insignificant. In particular, the risk of systemic infections and viral reactivation is a major concern.