Leucine‐Rich Alpha‐2 Glycoprotein Is Associated With Transmural Inflammation Assessed by Intestinal Ultrasound in Patients With Crohn's Disease

ABSTRACT Background Intestinal ultrasound (IUS) is a non‐invasive tool for evaluating transmural inflammation in Crohn's disease (CD). However, its utility is constrained by operator dependency and limited accessibility. Aims To explore the feasibility of serum biomarkers—specifically leucine‐rich alpha‐2 glycoprotein (LRG)—as an alternative to IUS for assessing transmural inflammation. Methods This retrospective, single‐centre study included patients with CD who underwent IUS and measurements of LRG and C‐reactive protein (CRP). We assessed correlations between biomarkers and five IUS scores (Limberg score, Bowel Ultrasound Score (BUSS), International Bowel Ultrasound Segmental Activity Score (IBUS‐SAS), Simple Ultrasound Score (Simple‐US) and Simple Ultrasound Score for Crohn's Disease (SUS‐CD)) using receiver operator characteristic curve analysis and Spearman's rank correlation coefficient. We conducted subgroup analyses for patients in clinical remission. Results We analysed 213 IUS examinations performed on 97 patients; 170 (80%) IUS were during clinical remission. The area under the curve for LRG for each IUS score (0.76, 0.80, 0.77, 0.75 and 0.69, respectively) was superior to that of CRP and was statistically significant, particularly for LS, BUSS, IBUS‐SAS and Simple‐US ( p < 0.001, p = 0.018, p < 0.001 and p < 0.001, respectively). Predictive values remained consistent among patients in remission. LRG demonstrated excellent correlation with IUS scores in both the overall patient population and those in remission. Conclusion LRG showed a robust correlation with IUS scores, suggesting its potential as a novel indicator for targeting transmural healing in patients with CD.