HLA mismatching within or outside of cross-reactive groups (CREGs) is associated with similar outcomes after unrelated hematopoietic stem cell transplantation.
The National Marrow Donor Program maintains a registry of volunteer donors for patients in need of a hematopoietic stem cell transplantation. Strategies for selecting a partially HLA-mismatched donor vary when a full match cannot be identified. Some transplantation centers limit the selection of mismatched donors to those sharing mismatched antigens within HLA-A and HLA-B cross-reactive groups (CREGs). To assess whether an HLA mismatch within a CREG group ("minor") may result in better outcome than a mismatch outside CREG groups ("major"), we analyzed validated outcomes data from 2709 bone marrow and peripheral blood stem cell transplantations. Three-hundred and ninety-six pairs (15%) were HLA-DRB1 allele matched but had an antigen-level mismatch at HLA-A or HLA-B. Univariate and multivariate analyses of engraftment, graft-versus-host disease, and survival showed that outcome is not significantly different between minor and major mismatches (P = .47, from the log-rank test for Kaplan-Meier survival). However, HLA-A, HLA-B, and HLA-DRB1 allele-matched cases had significantly better outcome than mismatched cases (P < .001). For patients without an HLA match, the selection of a CREG-compatible donor as tested does not improve outcome.
Wade
Judith A
JA
Department of Surgery, University of Toronto, Ontario, Canada.
Hurley
Carolyn Katovich
CK
Takemoto
Steven K
SK
Thompson
John
J
Davies
Stella M
SM
Fuller
Thomas C
TC
Rodey
Glenn
G
Confer
Dennis L
DL
Noreen
Harriet
H
Haagenson
Michael
M
Kan
Fangyu
F
Klein
John
J
Eapen
Mary
M
Spellman
Stephen
S
Kollman
Craig
C
D000483:Alleles; D003430:Cross-Sectional Studies; D018572:Disease-Free Survival; D005260:Female; D006086:Graft vs Host Disease / Q000209:etiology / Q000401:mortality; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D019337:Hematologic Neoplasms / Q000150:complications / Q000401:mortality* / Q000628:therapy*; D018380:Hematopoietic Stem Cell Transplantation; D006650:Histocompatibility Testing; D006801:Humans; D019520:Living Donors; D008297:Male; D036102:Peripheral Blood Stem Cell Transplantation; D012042:Registries; D012189:Retrospective Studies; D015996:Survival Rate
D015234:HLA-A Antigens; D015235:HLA-B Antigens; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains