Intestinal and Peripheral Fibrinogen-Like Protein 2 Expression in Inflammatory Bowel Disease

BACKGROUND: Fibrinogen-like protein 2 (FGL2), a new member of the fibrinogen-like family, has recently been identified as a novel immunosuppressive molecule. AIM: The purpose of this work was to investigate intestinal and peripheral expression of FGL2 in patients with inflammatory bowel disease (IBD), mainly ulcerative colitis (UC) and Crohn’s disease (CD). METHODS: FGL2 expression in mucosal biopsies from three groups (UC group (n = 61), CD group (n = 54), and controls group (n = 35)) was detected by immunohistochemistry. Concentrations of FGL2 in plasma from 50 UC patients, 45 CD patients, and 30 controls were analyzed by enzyme-linked immunosorbent assay. Western blot of FGL2 protein and real-time fluorescent quantitative PCR of FGL2 mRNA expression by peripheral mononuclear cells was performed. Correlations of FGL2 expression with disease type, activity, and location, and with measured laboratory data, including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), were examined. RESULTS: Intestinal and peripheral FGL2 protein data showed that FGL2 expression was significantly up-regulated in both UC and CD patients compared with controls (P < 0.001). Expression of FGL2 was higher in UC and CD patients with active disease than in those with inactive disease (P < 0.001). Moreover, FGL2 mRNA expression was significantly higher in patients with active disease than in those with inactive disease (P < 0.050). Expression of FGL2 protein was correlated with disease activity indices, CRP levels, and ESR levels. CONCLUSION: Expression of FGL2 was up-regulated in IBD patients with active disease. Measurement of FGL2 may be used as a helpful biomarker for understanding immunopathogenesis and for assessment of IBD.