Japanese experience of single-unit cord blood transplantation for adults

Abstract

 Unrelated cord blood transplantation (CBT) is a crucial modality of allogeneic hematopoietic cell transplantation for patients lacking related and unrelated donors and those who require prompt transplantation. In contrast to CBT practices in Western countries, Japanese CBT exhibits several distinct characteristics, such as the utilization of single-unit cord blood for both pediatric and adult patients, looser criteria for cord blood unit selection, and expanded indications for advanced diseases. Therefore, clinical evidence for CBT needs to be established through single or multi-institutional studies within Japan. Advancements in supportive care, including more careful patient selection based on disease type and status, more stringent cord blood graft selection based on cryopreserved CD34⁺ cell dose and the presence of donor-specific anti-HLA antibodies, safer conditioning regimens, and optimal graft-versus-host disease (GVHD) prophylaxis, have likely contributed to the recent improvement in neutrophil engraftment and early mortality after CBT for adults. Additionally, the development of mild GVHD after CBT may enhance survival by decreasing relapse and non-relapse mortality, particularly for high-risk groups.