MicroRNA-155 Overexpression in Inflammatory Bowel Disease Patients: Potential Role in Inflammation and Immune Regulation

Background: MicroRNA-155 (miR-155) is a pro-inflammatory molecule implicated in autoimmune and inflammatory diseases, including inflammatory bowel disease (IBD). This study evaluated circulating miR-155 expression in IBD patients versus healthy controls and its association with clinical markers. Methods: Thirty IBD patients (20 ulcerative colitis [UC], 10 Crohn’s disease [CD]) and 20 age- and sex-matched healthy controls were enrolled. Plasma miR-155 levels were measured using qRT-PCR. Clinical data included C-reactive protein (CRP), fecal calprotectin, and Mayo score (for UC). Analyses were conducted using SPSS v26.0. Results: miR-155 expression was significantly elevated in IBD patients (median fold change: UC = 24.2, CD = 37.5, controls = 1.00; p < 0.0001). No significant difference was observed between UC and CD groups. miR-155 positively correlated with fecal calprotectin (ρ = 0.475, p = 0.008) and Mayo score in UC patients (ρ = 0.748, p < 0.001). Conclusion: Circulating miR-155 is significantly overexpressed in IBD and correlates with intestinal inflammation and disease activity, supporting its utility as a non-invasive biomarker.