B HANDAN ÖZDEMİR, ALEV OK ATILGAN, AYDAN AKYÜZ ÖZDEMİR, EDA AKÇAY, MEHMET HABERAL
Experimental and Clinical Transplantation - 2023;21(7):568-577
Objectives: Allograft biopsy is the gold standard for diagnosing polyomavirus-associated nephropathy. We aimed to establish the effects of histopathologic findings proposed by the Banff Polyomavirus Working Group on graft outcome. We also aimed to understand the clinical importance of follow-up biopsies for patients with polyomavirus-associated nephropathy. Materials and Methods: Our study included 22 patients with polyomavirus-associated nephropathy. All biopsies were classified according to the latest Banff Polyomavirus Working Group classification. Follow-up biopsies of all patients were evaluated in detail. Results: The mean interval between polyomavirusassociated nephropathy and transplant was 10 ± 1.6 months. Of 22 patients, biopsy revealed stage 1 in 3 (13.6%), stage 2 in 17 (77.3%), and stage 3 in 2 patients (9.1%). Fourteen patients (63.6%) had polyomavirus viral load 3, 5 (22.7%) had polyomavirus viral load 2, and 3 had polyomavirus viral load 1. Among patients included in analyses, 18.2% had antibody-mediated rejection and 27.2% had T-cellmediated rejection simultaneously with polyomavirusassociated nephropathy. Graft loss increased with increasing polyomavirus-associated nephropathy class and polyomavirus viral load (P = .015 and P = .002, respectively). The mean time of graft survival decreased with increasing degree of tubulitis, interstitial inflammation, plasma infiltration, and neutrophil infiltration. Patients with interstitial fibrosis, glomerular polyoma, and cortical plus medullar involvement showed earlier graft loss. Follow-up biopsies showed that diffuse interstitial fibrosis or persistent inflammation negatively influenced graft loss. Conclusions: The Banff Polyomavirus Working Group’s schema significantly correlated with graft outcome. Early detection of polyomavirus-associated nephropathy and subsequent detection of persistent inflammation and interstitial fibrosis and tubular atrophy in follow-up biopsies and modification of immunosuppressive therapy can successfully prevent graft loss.
