LAUSR

The impact of ABO incompatibility on transplantation outcomes in severe aplastic anemia (SAA) patients receiving haploidentical hematopoietic stem cell transplantation (HSCT) remains controversial without published data. A total of 199 SAA patients receiving haploidentical HSCT from ABO-matched ( n  = 114), minor ABO-incompatible ( n  = 47), or major ABO-incompatible donors ( n  = 38) were included in this study. The median time and cumulative incidences of both myeloid and platelet engraftment in the ABO-compatible and ABO-incompatible groups were similar, and pure red cell aplasia was absent. Minor ABO incompatibility increased the rate of grade III–IV acute graft-versus-host disease (aGVHD) (ABO compatible: 6.14 ± 0.05%, minor incompatible: 19.15 ± 0.34%, and major incompatible: 10.53 ± 0.25%; P  = 0.051), but did not influence the rates of grade II–IV aGVHD or chronic GVHD (cGVHD). Minor ABO-incompatibility was identified as an independent risk factor for grade III–IV aGVHD by multivariate analysis (hazard ration (HR) = 4.00 (1.48–10.80), P  = 0.006). Chronic GVHD, mortality, and treatment failure were not increased in the minor ABO-incompatible group. For SAA patients receiving haploidentical HSCT, ABO compatible donors are better than ABO minor incompatible donors if several haploidentical donors are available.