Our first experience of transfusion support in allogenic bone marrow transplantations.

Incompatibility of blood group antigens in bone marrow transplantation (BMT) requires the depletion of red blood cells from donor bone marrow in order to avoid fatal transfusion reactions. We purified 72 human bone marrows prior to transplantation from red blood cells by a modified method using simple centrifugation and sedimentation in 6% dextran. Small-volume samples (n = 4) were prediluted with compatible homologous red blood cells to reduce the loss of stem cells during the preparation steps. 12 of 30 allogeneic bone marrows were ABO major incompatible with the patient's blood group. Although we did not observe any transfusion reactions nor graft rejections, in ABO incompatible transplantations, donor reticulocytes appeared 10 days later in the peripheral blood than in patients who received an ABO compatible bone marrow. Concordantly, incompatible patients needed 1.7 times more red blood cell units after BMT.