Differences in Pathologic Features and Graft Outcomes of Rejection on Kidney Transplant.

Background: Rejection is still a barrier to long-term allograft survival, but there are not many reports of clinical outcomes according to rejection types. The purpose of this study was to investigate differences in pathologic features and graft outcomes of rejection on kidney transplant (KT).

Methods: We retrospectively analyzed 139 kidney transplant recipients diagnosed to rejection by allograft biopsy results between 2006 and 2018. We divided kidney transplant recipients into 3 groups as follows: T cell-mediated rejection (TCMR), antibody-mediated rejection, and mixed rejection. We investigated clinical characteristics, pathologic findings, death-censored graft survival rates, and patient survival rates among the 3 groups.

Results: Mean follow-up duration was 113.5 (SD, 80.6) months. The mixed rejection group was the youngest significantly. There were no significant differences of the proportion of sex, KT type, KT number, number of HLA mismatches, induction immunosuppressant, and maintenance immunosuppressant among the 3 groups. In pathologic findings, microvascular inflammation and C4d were significantly different among the 3 groups. Death-censored graft survival of mixed rejection was the least. In multivariate analysis, recipient age, TCMR, and positive C4d were the risk factors associated with graft failure. However, patient survival rates showed no significant differences among the 3 groups.

Conclusions: Our study showed that mixed rejection had poor prognosis in comparison with TCMR and antibody-mediated rejection groups, and TCMR and positive C4d were the most important risk factors for graft survival. Therefore, constant monitoring through allograft biopsy and early treatment for rejection are very important in post-transplant clinical outcomes.