Bone marrow transplantation with major ABO incompatibility. Experience of the Bone Marrow Transplantation Unit--Francisco Gentil Portuguese Institute of Oncology, Lisbon Centre.

Thirteen patients submitted to bone marrow transplantation (BMT), HLA A and B identical, with mixed negative lymphocyte culture and major ABO incompatibility were retrospectively evaluated. Gravity sedimentation by hydroxyethyl starch was used in almost all cases to deplete erythrocytes from bone marrow (12/13): a removal rate of 90%--corresponding to an erythrocyte residual volume of 27,4 rate ml--and a nucleated cell recovery of 76% (mean values) were obtained. All patients underwent a hyperhydration regimen and received corticosteroid prophylaxis before bone marrow infusion. Considering the most important immunohematological problems associated to this type of transplant, we verified that seven patients developed minor complications and among them only one had long term consequences. In comparison with the control group, ABO identical and with minor incompatibility, the study group had delayed onset of erythropoiesis and needed greater erythrocyte transfusion support. We concluded that major ABO incompatibility does not constitute a drawback to BMT success in most patients.