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

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. 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. A retrospective observational study at a single tertiary care center. 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. 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. Serum gelsolin is a prospective noninvasive biomarker that outperforms CRP in detecting endoscopic disease activity in patients with ileocolonic-type CD.