Autoimmune cytopenias

The autoimmune cytopenias are characterized by the production of antibodies against blood cells and include autoimmune haemolytic anaemia (AIHA), autoimmune neutropenia (AIN), autoimmune thrombocytopenia (ITP) or various combinations of these conditions. They may be idiopathic (primary) or associated with an underlying malignancy, other systemic autoimmune disorders or may be drug-induced. Many patients respond to first-line therapy with corticosteroids although a high proportion relapse and require alternative therapy. Further treatment options include splenectomy or cytotoxic immunosuppressive agents, which are non-selective in their mechanism of action and associated with considerable toxicity. Patients with chronic resistant disease who do not respond to first- or second-line therapy are at particular risk of life-threatening bleeding (severe ITP), life-threatening anaemia (severe AIHA) or systemic sepsis (severe AIN or therapy-related neutropenia). There has been recent interest in the use of targeted, monoclonal antibody therapy to specifically ablate or suppress the autoreactive clone. Rituximab (anti-CD20) has been shown to produce durable responses in ITP and AIHA and may replace the need for splenectomy in some patients. Alemtuzumab (anti-CD52) is effective in AIN but may produce significant toxicity. Stem cell transplantation has been successful in a small number of highly refractory/resistant patients but carries with it a high risk of treatment-related morbidity and mortality.