Leucine-Rich Alpha-2 Glycoprotein Is a Reliable Serum Biomarker for Evaluating Clinical and Endoscopic Disease Activity in Inflammatory Bowel Disease

Background Leucine-rich alpha-2 glycoprotein (LRG) is a novel serum biomarker for inflammation in inflammatory bowel disease (IBD). This prospective study aimed to compare the value of LRG with C-reactive protein (CRP) and fecal calprotectin for evaluating clinical and endoscopic disease activity in patients with IBD. Methods At entry, clinical and endoscopic disease activity was assessed in 267 patients with IBD (ulcerative colitis [UC] 203; Crohn's disease [CD] 64), and the levels of LRG, CRP and fecal calprotectin were measured. The accuracy of the biomarkers for the detection of clinical and endoscopic disease activity was determined by the area under the receiver operating characteristic curve. Results Leucine-rich alpha-2 glycoprotein showed a significant relationship with the clinical and endoscopic severity in both UC and CD (both diseases, P < .0001). In the clinical assessment of UC, the accuracy of LRG was significantly higher than that of CRP (0.73 vs 0.63; P < .001). In the endoscopic assessment of UC, the accuracy of LRG was significantly higher than that of CRP (P = .01), but it was significantly lower than that of fecal calprotectin (P = .009; LRG, 0.80; CRP, 0.72; fecal calprotectin, 0.91). In the clinical and endoscopic assessment of CD, the accuracy was not significantly different between the biomarkers (clinical activity: LRG, 0.71; CRP, 0.64; fecal calprotectin, 0.66; in endoscopic activity: LRG, 0.79; CRP, 0.78; fecal calprotectin, 0.81). Conclusions Leucine-rich alpha-2 glycoprotein is a reliable serum biomarker for the assessment of clinical and endoscopic disease activity in patients with IBD. It can be an alternative to CRP for the assessment of UC. Lay Summary Leucine-rich alpha-2 glycoprotein is a reliable serum biomarker for the assessment of clinical and endoscopic disease activity in patients with IBD. It can be an alternative to C-reactive protein for the assessment of ulcerative colitis.