Selection of cord blood unit by CD34+cell number, CFU-GM number and allele-level HLA matching in single cord blood transplantation

•Single cord blood transplantation remains a standard choice for unrelated transplantation in Japan, and outcomes are improving in recent years.•Cord blood unit selection based on CD34+ cell number/kg and CFU-GM number/kg, rather than total nucleated cell number/kg, are associated with improved outcomes after single cord blood transplantation.•Zero-1 HLA allele mismatches were associated with engraftment, GVHD and leukemia relapse, whereas 2-7 mismatches had no detrimental effect on overall survival compared to 3 allele mismatches.