Background:
Allogeneic bone marrow transplantation across ABO incompatibility barriers may result in immune mediated hemolysis. Hemolysis may be avoided by RBC depletion from the graft. Invitro graft manipulations carry the risk of
hematopoietic stem cell loss, a factor that may be most important in graft failure. We report 16 major ABO blood group incompatible allogeneic bone marrow transplants using erythrocyte depletion of marrow prior to infusion.
Methods:
From March 1997 to July 2001 in Yonsei University College of Medicine, 16 patients underwent ABO blood group incompatible allogeneic BMT: 5 for acute myelocytic leukemia, 5 for severe aplastic anemia, 3 for acute lymphocytic leukemia, 2 for chronic myelocytic leukemia,
and 1 for myelodysplastic syndrome. RBC depletions were done with automatic cell separator, COBE Spectra (COBE BCT Inc., Lakewood, USA). RBC removal rates and mononuclear cell recovery rates were calculated. And the evidence of successful engraftment and intravascular hemolysis were also evaluated.
Results:The RBC removal rate was 99.1±0.0% and a mean of 1% of the original red cell volume was contained in the final infusate. The mononuclear cell recovery rate was 70.0±16.3% from the original MNCs. Fourteen patients tolerated the infusion of the marrow concentrates without any adverse effects. Two patients experienced hemoglobinuria, but disappeared within 2 days by continued observation. After transplantation, absolute neutrophil counts exceeded 500/㎕ by 10.8±1.9 days, platelet counts exceeded 50,000/㎕ by 30.5±8.5 days, and reticulocytosis sustained at >1% was by 25.8±13.9 days.
Conclusion:
RBC depletion from ABO major mismatched bone marrow aspirates by the automatic cell separator is a safe and effective technique.

Keywords: Bone marrow transplantation, Major ABO blood group incompatibility, Erythrocyte depletion, Cell separator