Immunohistochemistry Analysis in Inflammatory Bowel Disease—Should We Bring to Light Interleukin-10?

<b>Background/Objectives:</b> Inflammatory bowel diseases (IBDs) are chronic intestinal disorders with an unpredictable course. In parallel with the advent of new biologic therapies targeting specific interleukin pathways, end-point targets have become more stringent, aiming for mucosal and even histologic healing. <b>Methods:</b> We conducted a prospective study assessing immunohistochemical (IHC) parameters in 46 IBD patients treated with biologic therapy. A similar IHC analysis was performed for comparison with a cohort of 10 "non-IBD" patients. <b>Results:</b> The highest integrated optical density (IOD) of TNF-α was observed in patients with dysplasia, abscesses, mucin depletion and basal plasmacytosis. Non-responders had higher pre- and post-treatment TNF-α expression in both UC and CD compared to responders. On the contrary, the same analysis conducted in the subpopulation treated with anti-TNF-α therapy (Infliximab and Adalimumab) did not reveal a substantial difference in TNF-α expression between responders and non-responders. High pre-treatment interleukin-10 expression was associated with biologic therapy failure, histological inflammatory activity and longer disease duration. <b>Conclusions:</b> Pre-treatment assessment of IL-10 might be a useful tool for identifying a high-risk subset of IBD patients and determining a more aggressive therapy and intensive monitoring strategy.