Unrelated umbilical cord blood can improve the prognosis of haploidentical hematopoietic stem cell transplantation

Background Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is widely used as a curative treatment strategy for most types of hematological diseases. However, strategies for enhancing the graft versus leukemia (GVL) effect without aggravating the graft versus host disease (GVHD) effect are still being pursued. Methods A retrospective cohort study was performed to compare the outcomes between combined unrelated umbilical cord blood (UCB-haplo HSCT) and haplo HSCT. Results The results showed that neither acute GVHD (aGVHD) nor chronic GVHD (cGVHD) was increased in the UCB-haplo HSCT group, and the engraftment and infection rates were similar between the two groups. However, overall survival and progression-free survival were significantly improved, while transplantation-related mortality and relapse were significantly decreased in the UCB-haplo HSCT group by both univariate and multivariate analyses. Conclusion Our results indicated that the addition of a UCB unit could improve the prognosis of haplo-HSCT and enhance the GVL effect without increasing the incidence of GVHD. Trial registration The cohort study was retrospectively registered at Keywords: Haploidentical hematopoietic stem cell transplantation, Unrelated umbilical cord blood, Graft versus leukemia, Graft versus host disease, Prognosis