ABO incompatibility as an adverse risk factor for survival after allogeneic bone marrow transplantation

BACKGROUND: Graft ABO incompatibility has not been thought to affect patien t survival after allogeneic bone marrow transplantation, although it may be associated with prolonged erythroid aplasia and immediate or delayed hemol ysis. STUDY DESIGN AND METHODS: A retrospective analysis of a cohort of 292 allog eneic transplant recipients measured survival in a subgroup of ABO-incompat ible bone marrow graft recipients. RESULTS: Patients with acute myelogenous leukemia or myelodysplastic syndro me receiving non-T-cell-depleted bone marrow grafts had an 85-percent great er risk of death within 100 days of transplant (relative risk, 1.85, 95% CI , 1.33-2.58; p = 0.003) than comparable patients receiving ABO-compatible g rafts. Both ABO major- and minor-mismatched graft recipients were at risk. The increased mortality rate was not due to an increase in graft failure or acute graft-versus-host disease; rather, patients died of multiple-organ f ailure and sepsis, which is consistent with regimen-related toxicity. This effect was not seen in a larger group of 112 chronic myelogenous leukemia p atients undergoing similar treatment. CONCLUSION: ABO incompatibility may be a significant prognostic risk factor after allogeneic bone marrow transplantation in susceptible subgroups of r ecipients. Care is necessary to design hematopoietic stem and progenitor ce ll-processing and -transfusion policies to minimize this risk.