Impact of renal allograft histopathological findings on transplant patient outcomes and graft survival: A retrospective single-center study

Introduction: This study aimed to evaluate the reasons for kidney transplant dysfunction by analyzing allograft biopsy findings. We also compared clinical outcomes and graft survival rates in patients with and without de novo donor-specific antibodies (DSA). Methods: This retrospective observational cohort study included 79 patients who underwent kidney allograft biopsy. The patients were divided into two groups based on the presence of anti-human leukocyte antigens (HLA) DSA antibodies. Laboratory evaluations included HLA-DSA and serum creatinine levels. The immunosuppressive therapy protocols were as follows: patients with single-antigen bead-measured sensitization (panel reactive antibody >50 %) received induction therapy, and all patients received triple therapy with tacrolimus or cyclosporine, prednisone, and mycophenolate sodium. Results: Acute antibody-mediated rejection (AMR) occurred in 20.2 % of patients, whereas acute T-cell-mediated rejection (TCMR) was observed in 14 %. Interstitial fibrosis and tubular atrophy were observed in 53.8 % and 69.2 % of patients with de novo DSA, respectively, compared with 15.2 % and 87.9 % in the non-DSA group. Calcineurin inhibitors induced nephrotoxicity in 11.4 %, relapse of the underlying disease in 13.9 %, and infection in 7.6 % of biopsies. Differences in serum creatinine levels were observed between the de novo DSA and non-DSA groups from the third (p = 0.039), fifth (p = 0.028), and seventh years of follow-up (p = 0.012). The graft survival rate was lower in patients with de novo DSA than in those without (p = 0.036). Conclusions: TCMR and AMR were the most common findings. The occurrence of AMR significantly impacted renal function and graft survival, and patients with de novo anti-HLA antibodies had poorer outcomes.