Can Urinary Mannose-Binding Lectin and Cathelicidin Ll-37 Predict Renal Allograft Fibrosis? Insights From a Pilot Study Publisher



Baghshahi P B ; Mirzakhani M ; Oliaei F ; Nowroozi M R ; Sharifi L ; Afrouzi M M
Source: Translational Research in Urology Published:2026

Abstract

Introduction Kidney transplantation is assumed as the best treatment for patients with end-stage renal disease (ESRD). Mannose-binding lectin (MBL) and Cathelicidin are members of innate immune system; MBL contributes to graft tubulointerstitial fibrosis post-transplantation, while Cathelicidin prevents collagen synthesis. This study aimed to assess the association of urinary levels of MBL and Cathelicidin with graft fibrosis and outcome. .Methods Random urine samples were collected from 10 renal transplant patients and seven healthy controls. Serum creatinine and urine total protein were measured and urinary MBL, and LL-37 were assessed using ELISA. Results The urinary MBL was significantly higher in patients (107.0±91.98 ng/ml) versus controls (3.932±10.40 ng/ml, P-value=0.01). Urinary Cathelicidin LL-37 levels were 158.1±89.33 ng/ml in patients and 174.0±54.26 ng/ml in controls (P-value=0.68) but LL-37 level was significantly higher in patients with severe fibrosis compared to mild fibrosis (211.4±82.2ng/ml vs. 104.7±63.8 ng/ml), P-value=0.05). Conclusions Our exploratory study underscores the importance of innate immune mediators in urine as accessible indicators for monitoring renal graft injury, rather than current invasive biopsy-based methods. Elevated urinary MBL is associated with renal graft dysfunction and may serve as a non-invasive biomarker for chronic rejection. Cathelicidin LL-37 may show fibrotic severity and play a protective immunomodulatory role and can be applied as a biomarker for the severity of fibrosis follow up in renal graft patients. Future studies with larger cohorts are needed to validate these findings and clarify the clinical utility of urinary MBL and LL-37 as non-invasive fibrosis biomarkers. Copyright © 2026 Urology Research Center (URC), Tehran University of Medical Sciences.