Independent of nephrectomy, weaning immunosuppression leads to late sensitization after kidney transplant failure.

Background: Patients returning to dialysis therapy after renal transplant failure have a high rate of human leukocyte antigen antibody sensitization, and sensitization has been linked to allograft nephrectomy. We hypothesized that nephrectomy for cause is a consequence of weaning immunosuppression and that weaning leads to sensitization even in the absence of nephrectomy.

Methods: We examined outcomes in 300 consecutive patients with kidney allograft failure and survival of more than 30 days after failure. We analyzed a subset of 119 patients with a low panel reactive antibody (PRA) before transplantation and follow-up PRA testing at 6 to 24 months after failure (late PRA).

Results: By late PRA testing, 56% of patients were highly sensitized (class I or II PRA ≥80%). On multivariate analysis controlling for human leukocyte antigen matching, allograft nephrectomy, and other variables, weaning of immunosuppression predicted high sensitization (odds ratio, 14.34; P=0.004). In a subset of patients, the percentage of those who were highly sensitized increased from 21% at the time of failure on immunosuppressive therapy to 68% by late PRA after weaning (P<0.001). Conversely, patients who maintained immunosuppression showed minimal sensitization after failure. Transplant nephrectomy was required in 41% of patients who weaned immunosuppression versus 0% of the 24 patients who maintained immunosuppression with calcineurin inhibitor therapy after failure (P<0.001).

Conclusions: Weaning immunosuppression was a triggering event leading to late rejection and allograft nephrectomy and was an independent predictor of alloantibody sensitization after kidney allograft failure.