Interstitial fibrosis and tubular atrophy on protocol biopsies at 1 year after renal transplantation

Background: Advancements in immunosuppressive therapy have enabled control of early acute rejection and improved long-term kidney transplantation (KT) survival. Chronic histopathologic changes influence graft survival rate. We examined tubulointerstitial changes at 1 year after KT, focusing on the progression of interstitial fibrosis and/or tubular atrophy (IF/TA).

Methods: Using the Banff' 07 classification, we assessed the histological findings obtained at 1 year after transplantation of 38 patients who underwent the procedure between January 2008, and March 2010. In 24 cases, we obtained scores for interstitial fibrosis (ci) >1 and/or tubular atrophy (ct) > 1. We classified the patients into two groups, namely, less than borderline changes (BCs) (t0, i0, or i1; group A) versus BCs and above (t > 1, i2, or i3; group B). We compared their baseline data, renal function, and pathological scores.

Results: The mean serum creatinine levels were 1.06 mg/dL for group A and 1.32 mg/dL for group B. The "ct" grading according to the Banff' 07 classification was 0.83 for group A and 1.50 for group B (both P < .05). No significant difference was observed with respect to the percentage of patients with IF/TA (Banff category 5).

Conclusion: Patients more within 1 year after KT with BCs who show irreversible tubular atrophy by biopsy experience impaired renal function. The presence of BC at the first year may not be associated with IF/TA.