[Cord blood transplantation for leukemia in nonremission]

Cure rates achieved with allogeneic hematopoietic cell transplantation (allo-HCT) for nonremission leukemia have been largely unsatisfactory (10-20%). Cord blood (CB) transplantation has long been thought to have a low propensity for graft-versus-leukemia (GVL) effect because of the low incidence of graft-versus-host disease (GVHD). However, several retrospective studies have revealed that GVL effect of CB transplantation is comparable to or even greater than that of peripheral blood (PB) or bone marrow (BM) transplantation. The underlying mechanism of this phenomenon remains unclear; however, basic research has revealed some unique characteristics of immune cells in CB which are distinct from those of PB or BM. In clinical transplantation, the observed systemic immune-mediated manifestations in the pre-engraftment phase are also specific to CB transplantation. These findings suggest that CB is a potential donor source for patients in nonremission due to its unique immunological potential as well as rapid availability for nearly all patients in the near future.