Immunosuppression for failed allograft: how prolonged and much is adequate?

Abstract Background and Aims The development of human leukocyte antigen (HLA) antibodies towards a failed allograft is a critical factor for the feasibility and outcomes of future transplantation. Therefore, we investigated the factors contributing to sensitization in patients with failed allografts. Method A single-center retrospective study of patients with failed allografts between 2010 and 2020 was performed. Samples for HLA antibodies were tested at the time of graft failure and after immunosuppression withdrawal. Sensitization was defined as more than 80% of calculated Korean panel reactive antibody (PRA) I or PRA II. In addition, variables for affecting sensitization were collected. Results Twenty-three patients were included in the study. The mean flow-up duration after failed allograft was 43 ±33.3 months. The sensitized patients tended to have a longer follow-up period and were exposed to less total calcineurin inhibitor (CNI) than non-sensitized patients. (non-sensitized vs sensitized patients : 27.1±12.9 vs 51.7±37.8 months, p = 0.196; 4.2±4.9 vs. 5.1±2.9 months, p = 0.231 respectively). In multivariate logistic analysis, there was no significant difference regarding the total exposure to CNI and follow-up duration (sensitization group: multivariate odds ratio [OR] 1.188, 95% confidence interval [CI] 0.55–2.52, p = 0.655, OR 1.03, 95% CI 0.97–1.10, p = 0.282, respectively). In some patients, even prolonged immunosuppression after returning dialysis therapy did not prevent sensitization toward failed allograft. Conclusion In this study, there was no significant difference regarding the contributing factors for sensitization in the multivariate logistic analysis. However, in sensitized patients, trends were showing longer follow-up duration and less CNI exposure. Sensitization towards a failed graft might be affected by the dose and duration of immunosuppressant. Finally, the small sample size is one of the limitations of this study, and additional prospective research analysis for patients with failed allografts is needed in the future.