Does re-exposure to mismatched HLA antigens decrease renal re-transplant allograft survival?

We analyzed 420 kidney retransplants at the University of Minnesota, 87 of which did and 333 which did not share HLA mismatches with the previous transplant. There was no difference in outcome. We conclude that exceptions to routine HLA matching policies do not have to be made for kidney retransplants. Objective: To determine if the kidney graft functional survival rate for retransplants is influenced by presence of HLA mismatches in common with the previous (failed) transplant. Summary background data: Kidney retransplants have a lower function rate than primary grafts. An anamnestic response to HLA antigens shared with the previous donor could be one factor responsible, but reports in the literature are conflicting. Methods: Of 420 kidney retransplants with HLA information done at the University of Minnesota, 87 shared ≥ 1 HLA antigens specifically mismatched with the previous donor (63 cadaver and 24 living donor retransplants), while 333 did not (247 cadaver, 86 living donor). Patient and graft survival rates were calculated by life-table analysis for recipients with vs. without repeat mismatches, with the significance of differences determined by the Lee-Desu statistic. Results. Patient and kidney graft retransplant survival rate curves were not significantly different (p ≥ 0.41) for those exposed or not exposed to the same HLA mismatches as before. At 2 years, 70% vs. 61%, respectively, of cadaver grafts and 71% vs. 78%, respectively, of living donor grafts were functioning. Conclusions. The probability of a successful outcome with a kidney retransplant is no different for patients who do than for those who do not receive an organ sharing HLA mismatches with the previous donor. Exceptions to routine HLA matching policies do not need to be made for kidney retransplants.