Interferon Regulator Factor 5: A Novel Inflammatory Marker and Promising Therapeutic Target in Ulcerative Colitis

Background: Inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), is characterized by chronic inflammation affecting the gastrointestinal tract and extraintestinal organs. The etiology of IBD is multifactorial, involving genetic, immunological, and environmental factors. Over 200 genetic loci have been associated with the disease, indicating a significant genetic predisposition. Despite advances in understanding its genetic basis, clinical management remains challenging due to heterogeneity in disease presentation and variable treatment responses. Current therapies, such as 5-aminosalicylates and biologics, are not universally effective, underscoring the need for reliable biomarkers to predict therapeutic responses. Objective: This study investigates the potential role of interferon regulatory factor 5 (IRF5) in the pathogenesis of IBD, with a particular focus on UC. Methods: We conducted a systematic analysis of colon biopsies from 30 adult patients diagnosed with UC and from 8 non-IBD controls. Immunostaining was performed to assess IRF5 expression in colonic tissues using the primary IRF5 antibody (1:300, Abcam, ab181553). Statistical analyses evaluated the correlation between IRF5-positive cell counts, disease activity, and inflammatory markers such as calprotectin. Results: Our analysis revealed a significant increase in IRF5-positive macrophage-like cells in the inflamed mucosa of IBD patients compared to healthy controls. The number of IRF5-positive cells showed a positive correlation with disease activity and calprotectin levels, indicating that higher IRF5 expression is associated with increased inflammation. Conclusions: This study demonstrates a significant correlation between IRF5 expression and disease activity in UC, suggesting that IRF5 may play a crucial role in the inflammatory processes of the disease. The findings propose IRF5 as a novel biomarker for therapeutic intervention in IBD. Further research is needed to clarify the mechanisms by which IRF5 contributes to IBD pathogenesis and to explore the therapeutic potential of targeting this pathway in clinical settings.