[Research Advances on Clinical Application of Umbilical Cord Blood Transplantation in the Treatment of Hematological Diseases--Review].

Abstract　　Umbilical cord blood (UCB) is an alternative source of hematopoietic stem cells (HSCs) for patients who were lack of HLA match related or unrelated donors. Compared with bone marrow and mobilized peripheral blood, UCB has the advantages of easy availability, safety for donors, and low requirement for HLA match between donors and recipients. However, the cell amount in UCB is relatively less, which was associated with increased graft failure, delayed hematologic recovery, immune reconstitution, and higher transplant related mortality after UCB transplantation (UCBT). Double-unit UCB is a straightforward method to augment cell amount in UCB. Compared with single-unit UCBT, double-unit CBT associated with less risk of primary disease relapse and increased incidence rate of graft-versus-host disease (GVHD), but the hematologic recovery and overall survival of recipients were no significantly difference between single and double-unit UCBT. Novel strategies for UCB expansion significantly increased the cell amount in UCB, single-unit expanded UCBT not only increased the sources of UCB, but also decreased the high cost of double-unit UCB. ATG can decrease the risk of graft failure and GVHD rate, but the role of ATG in UCBT is still controversial. Herein, the recent clinical advances on UCBT in the treatment of hematologic diseases are systematically reviewed.