Treatment of chronic active T cell-mediated rejection after kidney transplantation: A retrospective cohort study of 37 transplants.

Aim: Data on the treatment of chronic active T cell-mediated rejection (CA-TCMR) are scarce, and therapeutical strategies for CA-TCMR have not been established. We retrospectively evaluated the outcomes and effects of treatment on pathological and clinical findings in patients with CA-TCMR.

Methods: This study comprised 37 patients who underwent kidney transplantation at our institute who were diagnosed with CA-TCMR between January 2018 and December 2020. Patients were followed until October 2021.

Results: A total of 32 of the 37 patients were treated. During the observation period, two patients died (5%), and five patients developed allograft loss (13%). A univariate Cox proportional hazards model showed that indication biopsy, higher spot urine protein/creatinine ratio (UPCR) and Banff ci/ct scores were risk factors for allograft loss. Of the treated patients, 23 underwent follow-up biopsies. The Wilcoxon signed-rank test showed significant improvement in the Baff scores for "ti", "i-IFTA", "t" and "t-IFTA" after treatment. On pathology, 13 (57%) of the patients who underwent follow-up biopsy improved to "no evidence of rejection" or "borderline change." Assuming that improvement in pathology to "borderline change" or "no evidence of rejection" on follow-up biopsy indicates response to treatment, multivariate logistic analysis showed that lower UPCR was a predictive factor for response to treatment. No specific effect of treatment type was observed.

Conclusions: Our results indicate that treatment could improve the pathological findings in CA-TCMR.