Cord blood transplantation from unrelated donors: A preliminary report from the Japanese Cord Blood Bank Network

As a source for hematopoietic stem cell transplantation (HSCT), cord blood transplantation from unrelated donors (UCBT) is now considered as an acceptable alternative to patients who need unrelated HSCT. To confirm the findings that mismatched UCBT is feasible, we discussed here the results for 477 patients with hematologic malignancies and non-malignancies who were subjected to UCBT coordinated by the Japanese Cord Blood Bank Network (JCBBN). From February 1997 to October 2001, 411 patients with malignancies and 66 with non-malignancies had UCBT through the cord blood bank in the JCBBN; 311 patients had HLA 0-1 mismatched UCBT; 165, had a 2-4 HLA mismatch. The Kaplan-Meier estimates for 3-year disease-free survival rate (DFS) were 35.2 ± 2.8% in malignant diseases, and 33.6 ± 7.2% in patients with non-malignant diseases. The HLA disparity had no effect on DFS, incidence of acute graft-versus-host disease, or engraftment. As reported previously, we also noted the importance of graft cell dose in determining survival in UCBT. Major advantages of UCBT include its rapid availability compared with unrelated donor bone marrow, and tolerance of an HLA mismatch at 2 loci, which will enable extension of the donor pool. This review outlines the latest UCBT progress, with emphasis on practical considerations in HLA-mismatched umbilical cord blood selection.