Transfusion Clinique et Biologique, vol.27, no.3, pp.115-121, 2020 (SCI-Expanded)
Introduction: The impact of ABO mismatch on outcomes following allo-HSCT remains controversial. In this study, our aim is to define the effect of ABO mismatch on post-transplant outcomes, engraftment kinetics and complications in a large cohort. Patients and methods: We retrospectively identified 1000 patients who underwent allo-HSCT from either bone marrow or peripheral blood stem cells at our center between 1988 and 2016. P < 0.05 was considered statistically significant. Results: Five hundred and ninety (59%) patient-donor pairs were ABO matched, 164 (16.4%) were ABO major mismatched (MM), 191 (19.1%) were ABO minor MM, and 55 (5.5%) were ABO bi-directionally MM. ABO matched pairs were more common in transplants from related donors (P < 0.001) and using bone marrow as a stem cell source (P < 0.001). In minor ABO MM transplantations, mild delayed hemolytic reaction occurred more frequently compared to major and bidirectional ABO MM transplantations (47% vs 35% and 18%, P < 0.001). Neutrophil engraftment was slightly delayed in ABO MM patient-donor pairs when compared ABO matched donor pairs according to median engraftment time in all group (167/410, 41% vs 204/590, 35%, P = 0.046). Pure red cell aplasia was diagnosed in 6 patients (1%). Higher risk of death was shown in ABO MM transplants compared to ABO matched transplants in overall survival (OS) analysis (HR:1.201, 95% CI:1.004–1.437, P = 0.045). The non-relapse mortality (P = 0.546) and cumulative incidences of acute graft versus host disease (aGVHD) and chronic (c) GVHD were comparable between ABO MM and ABO matched patient-donor pairs (for aGVHD, P = 0.235; for cGVHD, P = 0.137). Conclusion: ABO MM transplants were associated with decreased OS and slightly delayed neutrophil engraftment. NRM and the risk of GVHD were not related to ABO incompatibility.