Pure red cell aplasia following major ABO-incompatible allogeneic hematopoietic stem cell transplantation

Six out of 20 patients undergoing a major ABO-incompatible allogeneic stem cell transplantation (allo-HSCT) developed pure red cell aplasia (PRCA), which did not show any effects on granulocyte and platelet engraftment, and incidence of grade II-IV aGVHD. All the 6 cases of PRCA were in blood group O recipients of grafts from blood group A donors (n = 5) or blood group B donor (n = 1), suggesting that donor/recipient pair (A/O) is associated with a high risk of PRCA after major ABO-incompatible allo-HSCT. Erythroid engraftment occurred spontaneously in four cases without specific intervention other than the RBC transfusion, which coincided with the decrease of isoagglutinin titers below 8, and the remaining 2 patients with prolonged erythroid aplasia( > 300 days) despite therapy with erythropoietin (EPO) were successfully treated by plasma exchange with donor-type plasma replacement. Cyclosporine did not appear to have played any role in causing PRCA in our patients, however, the occurrence of GVHD may facilitate the recovery of erythropoiesis.