HLA-incompatibility is a major factor associated with outcome of allogeneic stem cell transplantation, but little is known on the impact of isolated HLA-C mismatches. We analyzed the outcome of 114 CML patients transplanted with marrow from unrelated donors of whom 24 were mismatched for HLA-C only (9/10 match). Univariate estimates of 5-year survival (SRV) (median follow-up: 47 months) in the HLA-matched group were 68±12 vs 42±20% (P = 0.03) for the patients mismatched for HLA-C only and 33±33% in the mismatched group (non-HLA-C single mismatches and multiple mismatches) (P = 0.0004). Disease stage, GVHD-prophylaxis (T-cell depletion), CMV-status anal HLA-incompatibility were the risk factors associated (all P ≤ 0.005) with poor outcome. In the multivariate analysis, patients mismatched for loci other than HLA-C were at high risk of an adverse outcome (death: RR, 2.9; CI, 1.6-5.4, P = 0.008, transplant-related mortality (TRM): RR, 3; CI, 1.5-5.9, P = 0.0015). For patients mismatched for HLA-C only, the increased risk was of borderline significance (death: RR, 1.9; CI, 1-3.9, P = 0.06, TRM: RR, 2.1; CI, 1-4.5, P = 0.07). In spite of their lower expression, HLA-C antigens still represent relevant transplantation barriers that should be considered when searching for an unrelated donor.

CML, GVHD, Hematopoietic stem cell transplantation, HLA matching, HLA-C, Unrelated donors
dx.doi.org/10.1038/sj.bmt.1704569, hdl.handle.net/1765/65414
Bone Marrow Transplantation
Department of Hematology

Tiercy, J.-M, Passweg, J, van Biezen, A, Zander, A.R, Kröger, N, Gratwohl, A, … Roosnek, E. (2004). Isolated HLA-C mismatches in unrelated donor transplantation for CML. Bone Marrow Transplantation, 34(3), 249–255. doi:10.1038/sj.bmt.1704569