Performance of serum gelsolin as a biomarker for mucosal activity in Crohn’s disease: a comparison with C-reactive protein

Background: Crohn’s disease (CD) is a chronic inflammatory bowel disease. Monitoring the disease activity and providing appropriate treatment are essential for improving long-term prognosis. Endoscopy remains the gold standard for assessing disease activity; however, it is invasive and costly. Recently, we identified gelsolin as a promising serum biomarker for endoscopic disease activity in ulcerative colitis. Objective: To investigate serum gelsolin levels as a potential biomarker for mucosal activity in the small bowel and colon of patients with CD. Furthermore, we aimed to compare the performance of gelsolin with that of C-reactive protein (CRP) in detecting mucosal activity. Design: A retrospective observational study at a single tertiary care center. Methods: Serum gelsolin and CRP were measured in 82 patients with CD and 16 healthy controls. Endoscopic disease activity was assessed using the Applied Simple Endoscopic Score for CD (aSES-CD). We conducted receiver operating characteristic curves and correlation analyses. In addition, subgroup analyses were performed to evaluate differences in the biomarker performance between ileal and ileocolonic types of CD. Results: Serum gelsolin levels were significantly lower in patients with CD than in healthy controls ( p < 0.001). Gelsolin levels were negatively correlated with aSES-CD, particularly in patients with the ileocolonic-type CD, and showed a stronger correlation with endoscopic activity than CRP. The area under the curve for gelsolin was 0.8377, with a cutoff of 13 µg/mL, yielding 75% and 83% sensitivity and specificity, respectively. Conclusion: Serum gelsolin is a prospective noninvasive biomarker that outperforms CRP in detecting endoscopic disease activity in patients with ileocolonic-type CD.