P158 Expression of IL-19 and IL-24 in intestinal mucosa of inflammatory bowel disease: An immunohistochemical study

Abstract

Abstract Background Interleukins are considered as targets for future inflammatory bowel disease ( IBD) treatments. IL-19 and IL-24 are members of IL-10 family and through the JAK-STAT pathway induce proinflammatory cytokine production. A retrospective single center study was performed to study the IL-19 and IL-24 expression in 121 patients with moderate to severe IBD, before and after treatment with biologics. Methods A retrospective study of 121 patients with moderate to severe IBD was performed using immunochemistry between 1999 and 2017. This study included 72 patients with Crohn's disease (CD), 49 with Ulcerative Colitis (UC) and 20 healthy controls. The age, gender, disease extent, severity and treatment choice were recorded. Endoscopy reports before and after 12 months of treatment were retrieved. Intestinal biopsy samples were retrieved from the Histopathology Lab before and 1 year after treatment with biologics. A signed consent was received from all the patients involved and the study was approved by the Bioethics Committee of Aristotle University of Thessaloniki. The histological specimen were stained for IL-19 and IL-24 before and one year after treatment with biologics. The results were analysed using SPSS for each of the IBD groups (CD, UC) and further to subgroups depending the biologic treatment they received, anti-Tumor Necrosis Factor alpha(anti-TNFa), Vedolizumab (VDZ), Ustekinumab (USK). Results A statistically significant increase was found in IL-19 and IL-24 patients in IBD patients versus healthy controls (P<0.05). On the biologics treated group and the anti-TNFa subgroup, there was statistically significant increase in IL-24 expression post treatment (P<0.01). In UC patients, the IL-24 expression was significantly increased after a successful treatment in relation with Mayo score ( P<0.01). On the CD group, a reverse statistically significant correlation was found between the pre-treatment IL-19 expression and the Harvey Bradshaw Index (H.B.I.) score reduction in the anti-TNFa and the VDZ subgroups (p<0.05). Conclusion A possibly proinflammatory role of IL-19 was found on the CD group. This can be used as a tool in the future to assess the disease activity and support the diagnosis as a diagnostic biomarker, as IL-19 was found normal in healthy controls. An anti-inflammatory role of IL-24 was found especially in the UC group and in relation with the activity index score post-treatment. This can be used potentially as a marker of response to treatment in active UC, assisting the clinical management. Further research is needed to delineate the exact role of these interleukins in intestinal inflammation.