We studied the effect of HLA-C matching in 515 patients after double umbilical cord blood (UCB) transplantation. After HLA matching HLA-A, -B, and -DRB1 at the allele level, we scored patients according to number of donor-recipient HLA-C matches at 4 possible loci: 2 from each donor unit, at the allele level. Given a direct interaction between HLA-A, -B, and -DRB1 matching and HLA-C score, we analyzed HLA-C matching in those receiving at least 1 2/6 to 4/6 HLA–matched unit (n = 389) versus those receiving only 5/6 or 6/6–matched units (n = 126). In those with at least 1 2/6 to 4/6 HLA–matched unit, a better HLA-C matching score was associated with significantly lower risk of death of any cause and nonrelapse mortality and better disease-free survival. There was no association with the risk of relapse, acute and chronic graft-versus-host disease, and hematopoietic recovery. In contrast, among patients receiving only allele-level 5/6 or 6/6 HLA–matched UCB units, HLA-C match had no demonstrable effect on any outcome. For patients receiving at least 1 allele-level 2/6 to 4/6 HLA–matched UCB unit, matching at HLA-C reduces nonrelapse mortality and improves survival.
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Financial disclosure: This work was supported in part by grants from the National Cancer Institute P01 CA65493 (C.G.B, T.E.D., M.R.V., J.E.W.), Leukemia and Lymphoma Society Scholar in Clinical Research Award, grant CDP-2417-11 (C.G.B.), and National Heart, Lung, and Blood Institute U54 HL081030-32 (CC and KKB).
- Alternative donor transplantation
- Double umbilical cord blood
- Human leukocyte antigen