Immunosuppressive therapy with antithymocyte globulin and cyclosporine for paroxysmal nocturnal hemoglobinuria

Immunosuppressive therapy (IST) for paroxysmal nocturnal hemoglobinuria (PNH) has been infrequently reported. Four PNH cases were treated with antithymocyte globulin (ATG) at our center. We assessed and reviewed the efficacy and safety of IST for PNH. ATG therapy was performed for progression of cytopenia in 3 classical-type and 1 marrow failure-type PNH cases. ATG was administered at a dose of 15 mg/kg for 5 consecutive days. Hydration and anticoagulant therapy were given as prophylaxis for thrombosis during ATG therapy. Cyclosporine was also given to the 3 classical-type PNH patients. Three patients showed hemolytic exacerbation and thrombocytopenia during ATG administration, and all needed to receive transfusions of red blood cells and platelets; however, renal failure and thrombosis did not occur. Anemia improved in all cases within 1 year, but thereafter, recurred in 2 cases. ATG therapy is a choice of treatment for PNH, although its mechanism remains unknown.