Late onset of autoimmune hemolytic anemia and pure red cell aplasia after allogeneic hematopoietic stem cell transplantation using in vivo alemtuzumab.

Hemolytic anemia and pure red cell aplasia (PRCA) after allogeneic hematopoietic stem cell transplantation (HSCT) have been reported to be mainly related to ABO-incompatibility between donor and recipient. Autoimmune hemolytic anemia (AIHA) without ABO-incompatibility has been also reported after allogeneic HSCT, especially with T-cell depletion. However, optimal management of AIHA or PRCA remains unclear. A 54-year-old male with myelodysplastic syndrome (MDS) underwent haploidentical human leukocyte antigen-mismatched HSCT using in vivo alemtuzumab and developed AIHA and PRCA simultaneously 15 months after transplantation, following the administration of cidofovir and probenecid for persistent cytomegalovirus (CMV) antigenemia and retinitis. AIHA was successfully treated with rituximab, and subsequently PRCA with cyclosporine without relapse of MDS or recurrence of CMV infection. The clinical course suggested that AIHA was mainly caused by humoral immune response, while PRCA was mainly caused by cell-mediated immune response in this patient, although these immune responses might be related to each other.