New horizons in transplantationKidney transplantationUrinary Type III Procollagen Is Associated With Chronic Allograft Dysfunction and Predicts Graft Survival

•Renal biopsy has some drawbacks.•Urinary PIIINP-to-creatinine ratio reflects the ongoing fibrotic processes in the kidney.•Urinary PIIINP-to-creatine level is a potentially useful noninvasive marker for graft survival in patients with CAD.

BackgroundChronic allograft dysfunction (CAD) is the most important clinical problem in solid organ transplantation. Interstitial fibrosis and tubular atrophy contribute to long-term renal allograft failure. Urinary type III procollagen N-terminal propeptide (PIIINP), has been shown to associate fibrotic processes.MethodsOne hundred sixty patients with CAD who underwent allograft biopsies were evaluated, and 52 patients with chronic or sclerosing allograft nephropathy were enrolled in the study. The subjects were divided into 2 groups according to the level of urinary PIIINP to creatinine (u-PIIINP-to-Cr): high procollagen group and low procollagen group. The association between u-PIIINP-to-Cr level at the time of biopsy and renal endpoints during 36 months of follow-up was assessed by multivariate Cox analysis.ResultsInterstitial fibrosis and proteinuria were higher in the high procollagen group compared with the low urinary procollagen group. Correlation analysis showed that levels of u-PIIINP-to-Cr were positively associated with fibrosis scores. During the follow-up, glomerular filtration rate (GFR) decreased in both study groups; however, GFR declined more in the high procollagen group than in low procollagen group. Cox regression model showed that the u-PIIINP-to-Cr levels, GFR, and proteinuria were independent risk factors associated with graft survival.Conclusionu-PIIINP-to-Cr level is a potentially useful noninvasive marker for graft survival in patients with CAD.