HLA-allele matched unrelated donors compared to HLA-matched sibling donors: role of cell source and disease risk category

Abstract

To determine whether the risks of allogeneic transplantation are different when the donor is a fully matched unrelated donor (MUD; based on 10/10 HLA alleles) compared to an HLA-identical sibling, we performed a retrospective analysis of 1448 patients with high-risk or advanced hematologic malignancies given T-replete grafts after myeloablative conditioning. No statistically significant differences were found between recipients of a matched sibling donor (MSD) and 10/10 MUD in survival, disease-free survival (DFS), and nonrelapse mortality (NRM) for patients with high-risk disease or those given bone marrow as a graft source. However, for patients with intermediate-risk disease receiving peripheral blood grafts, we observed higher NRM and lower overall survival (OS) in the 10/10 MUD group compared to the MSD cohort. Graft-versus-host disease (GVHD) was higher in the MUD group compared to the MSD group. These results suggest that if a patient has high-risk disease and an MSD is not available, selection of an HLA-allele-matched MUD may provide similar OS and DFS, and therefore lack of an MSD in and of itself should not preclude such a patient from undergoing transplantation. However, for patients with intermediate-risk disease, transplantation with peripheral blood from a 10/10 MUD is associated with lower survival than an MSD.

Figure

Disease-free survival (DFS) according to cell source. Kaplan-Meier estimates of DFS among recipients of bone marrow (BM, left panel) or peripheral blood stem cell grafts (PBSC, right panel) are stratified for disease-risk category (intermediate vs. high) and donor type (HLA-matched sibling (MSD) or a HLA-matched unrelated donor (10/10 MUD)). Among BM graft recipients with intermediate-risk disease, 239 received MSD and 183 received 10/10 MUD grafts; similarly for high-risk disease, 177 received MSD and 82 received 10/10 MUD grafts. Among PBSC graft recipients with intermediate-risk disease, 252 received MSD and 215 received 10/10 MUD grafts; similarly for high-risk disease, 217 received MSD and 83 received 10/10 MUD grafts.