Matching for private or public HLA epitopes reduces acute rejection episodes and improves two-year renal allograft function

Background. The current role of HLA matching in renal transplantation is controversial. Public HLA epitope matching has been suggested to be as advantageous as private HLA matching, with the added benefit of increasing recipients' access to well-matched grafts. Methods. In this single center study of 105 renal transplant recipients, we examined the association of HLA matching with early (0-3 months) and late (4-6 months) rejection episodes (RE), as well as renal allograft function up to 2 years after transplant. Results. Poor HLA-DR, but not HLA-A or -B, matching was associated with early RE (0 DR matches, RE=2.7+/-0.19, 1 DR match, RE=2.37+/-0.18, vs, 2 DR matches, RE=1.5+0.38; P<0.01), In contrast, poor HLA-B, but not HLA-A or -DR, matching was associated with late rejections (0 HLA-B matches, RE=1.1+/-0.51 vs. 1-2 HLA-B matches, RE=0.5+/-0.1; P<0,004), HLA-B matching was also associated with a significantly lower serum creatinine (SCr) level at 24 months (0 HLA-B matches, SCr=178+/-20 mu mol/L vs. SCr=132+/-6 mu mol/L for 1-2 HLA-B matches; P<0.025), Matching for 10 supertypic HLA-A and -B crossreactive groups was associated with reduced late graft rejection (0-2 residue matches, RE=1.15+/-0.18 vs. RE=0.62+/-0.12 for 3 to 7 residue matches; P<0.013) as well as a significantly lower SCr level at 24 months (0-2 residue matches, SCr=205+/-29 mu mol/L vs SCr=131+/-6 mu mol/L for 3 to 7 residue matches; P<0,001) after transplantation. Conclusions. HLA-DR matching was associated with a reduced frequency of early rejection episodes, whereas HLA-B or residue/cross-reactive group matching was associated with a reduced frequency of late rejection episodes and improved graft function at 2 years.