Combined impact of HLA-allele matching and the CD34-positive cell dose on optimal unit selection for single-unit cord blood transplantation in adults

Abstract

The combined effects of HLA-allele matching at six-loci (HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1) and CD34⁺ cell dose on clinical outcomes were analyzed in 1,226 adult cases with single-unit unrelated cord blood transplantation. In the six-loci analysis, low HLA-allele matches did not significantly increase the overall mortality compared to higher matches, whereas in the five-loci analysis excluding HLA-DPB1, they caused a higher overall mortality (HR 1.42, p = .002), possibly due to the graft-versus-leukemia effect of HLA-DPB1 mismatches. A lower CD34⁺ cell dose (<.50 × 10⁵/kg) resulted in higher mortality and lower engraftment; these inferior outcomes were offset by high HLA-allele matches (7-10/10 match), while the inferior outcomes of low HLA-allele matches were improved by increasing the CD34⁺ cell dose. Consideration of the combined effects of the CD34⁺ cell dose and HLA matching may expand the options for transplantable units when HLA matching or the CD34⁺ cell dose is inadequate.

Keywords:

• Cord blood transplantation
• HLA-allele matching
• CD34⁺ cell dose
• total nucleated cells
• HLA-DPB1
• UCB unit selection

Acknowledgments

The authors thank the patients, donors, and the staff members of the cord blood collection facilities, transplantation centers, and the Japanese Cord Blood Bank Network for their generous cooperation. The authors also thank Kazuyo Ohmura, Tomoji Ohtani, Miyuki Itoh, Mutsuko Minemoto, Atsuko Ogawa, and the late Yoshiharu Suzuki for their support of the research, and Toru Miyagi, Tadashi Nagai, Neslon Hirokazu Tsuno, and Takafumi Kimura for critical review of the research.

Disclosure statement

No potential conflict of interest was reported by the author(s).