Umbilical cord blood transplantation.

Umbilical cord blood transplantation (CBT) has been widely used as an alternative source of hematopoietic cell support for stem cell transplant patients. CBT offers several advantages over traditional stem cell sources, such as immediate availability, absence of risk for donors, lower risk of acute graft-versus-host disease, and a less stringent requirement for human leukocyte antigen matching. Recent studies suggest that CBT is a safe and effective strategy for adult patients lacking a suitable related or unrelated donor. However, delayed engraftment and delayed immune reconstitution are significant clinical problems. Novel strategies, such as the use of multiple donors, cotransplantation with accessory cells, ex vivo expansion of cord blood hematopoietic progenitor cells, graft manipulation to improve T-cell recovery, and pharmacologic interventions to restore early thymopoiesis, hold promise to enhance engraftment and immune reconstitution after CBT. These approaches may significantly increase the quality and availability of cord blood for transplantation.