Analysis of urinary TGF-β1, MCP-1, NGAL, and IL-17 as biomarkers for lupus nephritis.

This study was aimed to determine the diagnostic performance of transforming growth factor beta 1 (uTGF-β1), monocyte chemoattractant protein-1 (uMCP-1), neutrophil gelatinase-associated lipocalin (uNGAL) and interleukin 17 (uIL-17) in LN. Seventy participants were studied, categorized into three groups: 38 severe LN (class III-IV LN patients); 12 mild LN (class I-II LN patients); and 20 control (healthy volunteers). Diagnosis of SLE was based on the 1997 ARA criteria. Class NL classified according to ISN/RPS 2004. uTGF-β1, uMCP-1, uNGAL, uIL-17 levels were determined by ELISA, using spot urine. The level of uMCP-1 and uNGAL was significantly greater in severe or mild LN compared with control group (P<0.05). The level of uTGF-β1 and uIL-17 was significantly higher in severe LN than that controls group (P<0.05). The AUC of uTGF-β1, uMCP-1, uNGAL, uIL-17 was 66.50%; 86.90%; 87.50%; 71.70%, with the cut-off value of 27.13pg/ml; 1.54pg/ml; 446.30pg/ml; 36.62pg/ml. Only uNGAL showed a significant correlation with the activity (P=0.016; r=0.389) and chronicity indices (P=0.018; r=0.381). This study showed that uTGF-β1, uMCP-1, uNGAL, uIL-17 levels were increased in LN. The AUC values for each biomarker are indicating a good diagnostic value. Urinary NGAL had the best sensitivity and specificity followed by uMCP-1, uIL-17 and uTGF-β1. For combinations of two biomarkers, the best sensitivity and specificity were displayed by the combination of uTGF-β1 & u-NGAL, followed by uMCP-1 & uNGAL.