Anti-RhD immunoglobulin in the treatment of immune thrombocytopenia

Abstract

Immune thrombocytopenia (ITP) is an acquired bleeding autoimmune disorder characterized by a markedly decreased blood platelet count. The disorder is variable, frequently having an acute onset of limited duration in children and a more chronic course in adults. A number of therapeutic agents have demonstrated effi cacy in increasing the platelet counts in both children and adults. Anti-RhD immunoglobulin (anti-D) is one such agent, and has been successfully used in the setting of both acute and chronic immune thrombocytopenia. In this report we review the use of anti-D in the management of ITP. While the FDA-approved dose of 50 mg/kg has documented effi cacy in increasing platelet counts in approximately 80% of children and 70% of adults, a higher dose of 75 μg/kg has been shown to result in a more rapid increase in platelet count without a greater reduction in hemoglobin. Anti-D is generally ineffective in patients who have failed splenectomy. Anti-RhD therapy has been shown capable of delaying splenectomy in adult patients, but does not signifi cantly increase the total number of patients in whom the procedure can be avoided. Anti-D therapy appears to inhibit macrophage phagocytosis by a combination of both FcR blockade and infl ammatory cytokine inhibition of platelet phagocytosis within the spleen. Anti-RhD treatment is associated with mild to moderate infusion toxicities. Rare life-threatening toxicities such as hemoglobinuria, acute renal failure and disseminated intravascular coagulation have been reported. Recommendations have been proposed to reduce the risk of these complications. Anti-D immunoglobulin can be an effective option for rapidly increasing platelet counts in patients with symptomatic ITP.