Influence of mismatching of HLA cross-reactive groups on cadaveric kidney transplantation

Finding fully HLA-matched recipients for a given donor is not practical due to the allelic diversity of the loci. Cross-reactive group (CREG) matching has been considered a feasible alternative to HLA matching. However, the true efficacy of CREG matching in cadaveric kidney transplantation is controversial. Using conventional HLA and CREG classifications proposed by Rodey and McKenna, we counted the number of mismatches for 319 patients who received cadaver kidney transplants between 1992 and 2003 at Asan Medical Center in Korea. When we compared transplants with four or fewer HLA-A, -B, and -DR antigen mismatches with those with five or more, we observed a significant difference in 5-year survival rate (88.5% versus 78.6%; P = .0189). Transplants with no or one HLA-DR mismatch had a significantly better 5-year survival rate than those with two HLA-DR mismatches (87.9% versus 80.0%; P = .0469). Among transplants with one or two HLA-DR mismatches, transplants with zero or one CREG mismatch showed better 5-year graft survival rate than those with two or more CREG mismatches (89.4% versus 79.8%; P = .0415) only in McKenna's CREG classification. These results suggest that the impact of CREG mismatches on graft survival may depend on CREG classification and on the distribution of HLA-DR mismatches.