Improved access to kidney transplantation with favorable graft survival in highly sensitized candidates under the French acceptable mismatch program.

Abstract

The scarcity of the human leukocyte antigen (HLA)-compatible donor pool, which leads to a long waiting time for transplantation, often requires specific national or supranational strategies to improve kidney graft access for highly sensitized (HS) patients. Acceptable national mismatch priority is a way to increase the number of potential matched donors without increasing the immunologic graft failure risk. In 2005, the French Acceptable Mismatch program (AMP) was successfully introduced as a strategy to improve kidney allocation for HS patients. The AMP was enhanced in 2015, authorizing up to four HLA-A, -B, -DR, and -DQβ mismatches, provided that each mismatch was an acceptable antigen. Our study compared graft survival between AMP allocation and other kidney allocation modalities among HS recipients between 2016 and 2022 (N = 2,985). After adjustment for donor and recipient characteristics using Cox regression, we found that the risk of graft failure was higher for HS non-AMP transplantations (hazard ratio 1.19 [95% CI 1.04-1.36]; 1.31 [95% CI 1.08-1.59] with death censored). The French AMP improves access to kidney transplantation for HS patients. Post-transplant survival is comparable to other kidney allocation modalities, possibly because of the absence of preformed donor-specific antibodies in recipients' historical and recent serum, which is associated with reduced risk of rejection.