The power of cord blood cells

In this issue of Blood, Michel et al¹ showed in a well-designed randomized controlled study that single unrelated cord blood transplantation (UCBT), with adequate cell dose, remains the standard of care. The single-unit UCBT arm had good survival (∼70%), low transplantation-related mortality (TRM: 5-6%), and a lower rate of extensive chronic graft-versus-host disease (GVHD) compared with the double-unit transplantation arm. This study provides important information on optimal cord blood donor selection. In addition, this study, as well as data from other recent reports, shows that immune reconstitution after UCBT is excellent (provided no antithymocyte globulin [ATG] is given). Furthermore, by refining and individualizing the conditioning regimens used for UCBT, the survival chances may improve further.