OR41 PIRCHE-II: A novel tool to identify permissible HLA mismatches in kidney transplantation

Aim Individual HLA mismatches may have differential effects on graft survival after kidney transplantation. Therefore, there is a need for a reliable tool to define permissible HLA mismatches in kidney transplantation. We previously demonstrated that donor-derived Predicted Indirectly ReCognizable HLA epitopes presented by recipient HLA class-II (PIRCHE-II) play a role in de novo donor-specific HLA antibody formation after kidney transplantation. Moreover, we also showed that PIRCHE-II is involved in HLA antibody formation after pregnancy. In the present Dutch multi-center study we evaluated the possible association between PIRCHE-II and kidney graft failure in 2918 donor-recipient couples that were transplanted between 1995 and 2005. Methods For all donors-recipients couples, PIRCHE-II numbers were determined and related to graft survival in both univariate and multivariable analyses. Results Adjusted for confounders, the natural logarithm of PIRCHE-II was associated with a higher risk for graft failure (HR:1.13, 95% CI:1.04–1.23, p = 0.003). Univariately analyzed, patients with low PIRCHE-II numbers had a better 10-years graft survival than patients with higher PIRCHE-II numbers (p = 0.006; PIRCHE-II strata: Conclusions Our data suggest that the PIRCHE-II algorithm is a valuable tool to discriminate between permissible HLA mismatches and high-risk HLA mismatches in kidney transplantation. Inclusion of PIRCHE-II in donor-selection criteria may eventually lead to an improved kidney graft survival.