Arteriolopathy in non-episode biopsies of renal transplant allograft

Purpose. We have been performing protocol biopsies since 1995 to predict th e outcome of renal allograft. However, histopathological findings in renal allograft with stable function remain unclear. For this reason, we performe d non-episode biopsy on long-surviving renal allograft and investigated the histopathological changes. Among the several diseases seen in non-episode biopsies, arteriolopathy, such as drug-induced nephropathy, is one of the m ost frequent diseases. However, it is unrelated to the dosage and the conce ntration of cyclosporine or tacrolimus. Consequently, we evaluated the clin icopathological findings of arteriolopathy in this study in order to clarif y whether cyclosporine (CsA) or tacrolimus (FK506) is responsible for these findings. Materials and methods. We defined non-episode biopsy as a case with a serum creatinine level less than 2.0 mg/dL and containing less than 500 mg/dL of urinary protein. Final results showed that 71 cases were identified as non -episode biopsy. We then evaluated the histopathological cal findings and t he clinical characteristics of these cases. Results. Thirty-two of the 71 non-episode biopsy specimens showed findings of arteriolopathy. The frequency and the severity of arteriolopathy are not concerned with dosage and concentration of CsA or FK506. The arteriolopath y seen in non-episode biopsy was related to the time of the biopsy and the kidney age. Arteriolopathy in non-episode biopsy also had a relationship wi th hypertension, suggesting that it is important to strictly control blood pressure for graft survival.