Serological complications of a major ABO incompatible bone marrow transplantation in a Polynesian with aplastic anemia.

A 24-year-old, blood-group O Polynesian woman with multiple red blood cell antibodies received a group A, HLA-compatible, sex-matched bone marrow transplantation as treatment for severe aplastic anemia. High retransplantation titers of ABO isohemagglutinins were successfully reduced by repeated plasmaphereses. Despite gross in vitro incompatibility in the routine crossmatch, technetium-labelled red blood cell survival studies performed immediately prior to transplantation predicted that a small proportion of the donor erythrocytes would neutralize residual postplasmapheresis isoantibody. Donor marrow was subsequently infused without significant hemolysis. Although anti-A titers were low immediately posttransplantation, these rose progressively, approaching pretransplantation levels at the time of documented marrow engraftment at day 18. One week later the bone marrow graft was rejected. Retransplantation was successfully performed using marrow from an ABO compatible, sex-mismatched sibling donor. Radioisotopic studies were helpful in evaluating donor-recipient red blood cell incompatibility during the ABO incompatible transplantation, and again at retransplantation in the presence of circulating isoantibody to donor red blood cells. High levels of ABO isoagglutinins prior to plasmapheresis and rapidly rising titers posttransplantation may have predicted bone marrow graft rejection in this patient.