Persistent Chronic Active T-Cell-Mediated Rejection After Kidney Transplantation Is Associated With Poor Allograft Survival

Introduction: Histopathological findings of chronic active T-cell-mediated rejection (CA-TCMR) have been reported to potentially improve with treatment. However, whether this improvement is associated with a better renal prognosis remains unclear. This study was performed to analyze the impact of the histological response to therapy on kidney allograft survival in patients with CA-TCMR. Methods: The data of patients diagnosed with CA-TCMR between January 2018 and May 2023 were retrospectively reviewed. A composite graft endpoint was defined as a two-fold increase in the serum creatinine level or the development of end-stage kidney disease. Results: Thirty-seven patients with CA-TCMR underwent 46 follow-up biopsies. Eleven patients who were diagnosed with CA-TCMR at the last biopsy were classified as the persistent group, while the remaining 26 patients were classified as the transient group. Both before and after treatment, there were no significant changes in serum creatinine, estimated glomerular filtration rate, or proteinuria in either group. However, the transient group showed a significant reduction in interstitial fibrosis and tubular atrophy without a specific etiology (IFTA). This improvement was attributed to better histopathological Banff scores after treatment. Patients with persistent CA-TCMR had significantly worse graft survival than those with transient CA-TCMR (p = 0.002), even after adjusting for significant clinical factors (hazard ratio: 11.4; 95% CI: 1.1–120.0; p = 0.043). Conclusion: Our findings suggest that the persistence of histopathologic evidence of CA-TCMR after treatment is a significant risk factor for allograft loss compared with transient CA-TCMR.