ABO incompatibility between donor and recipient and clinical outcomes in allogeneic stem cell transplantation.

We performed a retrospective, cohort study to evaluate the impact on recipient survival of ABO incompatibility between recipient and donor after allogeneic stem cell transplantation, primarily involving marrow-derived cells. No statistically significant difference was noted in survival for 153 patients with acute or chronic leukemia or myelodysplastic syndrome receiving ABO identical or ABO mismatched allografts. Five patients who had allografts that were bidirectionally incompatible (both donor cells and plasma incompatible) did have significantly poorer survival than the other recipients, similar to the experience reported in one other cohort study. However, these patients had other risks for mortality, including being older and receiving transplants from matched, unrelated donors. Our data do not support a significant role for ABO donor-recipient matching in allogeneic stem cell transplantation.