Impact Of ABO Incompatibility On Overall Survival After Unrelated Cord Blood Transplantation a Single Institute Experience In China

Umbilical cord blood transplantation (UCBT) has now become a more common treatment for patients with hematologic malignancies who lack matched related or unrelated donors. However, few reports have addressed the impact of ABO incompatibility on the clinical outcomes, such as engraftment, transfusion requirements and survival after UCBT. Therefore, we retrospectively analyzed the impact of ABO mismatching on the clinical outcomes of 121 patients, including 51 ABO-identical, 23 minor, 39 major, and 8 bidirectional ABO-incompatible recipients after UCBT. With a median follow-up of 11 months (range, 5-151 months), the disease-free survival (DFS) rates among the ABO-identical, minor, major, and bidirectional ABO-incompatible groups were 71.7%, 60.0%, 37.1%, and 71.4%, respectively (P=0.014), whereas the OS did not differ significantly among the four groups (76.1%, 65.0%, 48.6%, and 71.4%, respectively; P=0.078). The DFS (68.2%, 42.9%; P=0.009) and OS estimates (72.7%, 52.4%; P=0.031) of the ABO identical/minor incompatible group also differed significantly from the ABO major/bidirectional incompatible group. These results were confirmed in the multivariate analysis. No significant differences in the engraftment times, transfusion requirements, graft-versus-host disease (GVHD), relapse, and non-relapse mortality (NRM) were noted among the groups. Severe immune hemolysis or pure red cell aplasia did not occur among these patients. These results indicate that ABO incompatibility somewhat affects the DFS and OS in UCBT, but further studies are still required.