Improving outcomes in umbilical cord blood transplantation: state of the art

Only 30% of patients who require an allogeneic hematopoietic cell transplant will have a HLA matched sibling donor. Many patients, particularly those patients with diverse racial and ethnic backgrounds, may not be able to identify a suitably matched unrelated donor. Over 25,000 umbilical cord blood transplant procedures have been performed in the last 25years. Considerable challenges exist in defining the appropriate conditioning regimen and graft vs host disease prophylaxis, surmounting issues of cell dose and delayed engraftment, and improving immune recovery. In this review, we discuss strategies to improve umbilical cord blood transplant outcomes, focusing on cord blood unit selection, expansion, and homing efficiency.