Features of interleukin-17 and interleukin-23 expression in patients with inflammatory bowel diseases
Authors: Yu.M. Stepanov, M.V. Stoikevych, O.M. Tatarchuk, T.S. Tarasova
Journal: GASTROENTEROLOGY (2025)

Background. Inflammatory bowel disease (IBD) is a serious medical and social problem, which leads to a significant interest in the study of etiology, pathogenesis, development of diagnostic and therapeutic complexes. There is growing evidence that interleukin (IL) 17 and IL-23 are potent mediators of inflammatory reactions in various tissues, including the intestine. In this regard, it is important to study cytokine levels depending on the activity of intestinal inflammation and the severity of IBD. The aim of the study was to determine the features of interleukins 17 and 23 expression in patients with inflammatory bowel disease. Materials and methods. We examined 80 patients with IBD (63 with ulcerative colitis (UC) and 17 with Crohn’s disease (CD)) who were divided according to the severity of the course. The control group consisted of 10 healthy individuals. Serum levels of IL-17 and IL-23 were determined by enzyme-linked immunosorbent assay using a Stat Fax 303 Plus analyzer (USA). Reagent kits from TECAN IBL International GmbH (Germany) were used in the study. Results. The concentration of IL-17 in patients with UC and CD was significantly higher, by 11.4 (p &lt; 0.05) and 17.6 times (p &lt; 0.05), respectively, compared to the control group. Its median level was 1.5 times higher (p &lt; 0.05) in the group with CD than in patients with UC. There was a significant increase in the median level of IL-23 in participants with UC (8.1-fold, p &lt; 0.05) and CD (7.5-fold, p &lt; 0.05) compared to controls, but it did not differ significantly between nosologies. The level of IL-17 was significantly higher in patients with moderate and severe UC than in the control group. No significant differences in IL-17 levels were found between patients with varying severity of UC. The median level of IL-23 was significantly higher in patients with moderate (7.4-fold, p &lt; 0.05) and severe UC (11.2-fold, p &lt; 0.05) compared to controls. In severe UC, the concentration of IL-23 was 1.5 times higher (p &lt; 0.05) than in moderate UC. Correlations were found between IL-23 levels and the endoscopic activity index (r = +0.347; p = 0.005) and Mayo index (r = +0.295; p = 0.020). The content of IL-17 was 9.9 (p &lt; 0.05) and 9.0 times (p &lt; 0.05) higher in patients with moderate and severe CD, respectively, without a significant difference depending on severity. In the group with severe CD, the level of IL-23 was 1.6 times (p &lt; 0.05) higher than in patients with moderate CD. Conclusions. The median level of IL-17 was 1.5 times higher (p &lt; 0.05) in the group with CD compared to UC patients. The content of IL-23 tended to increase in UC compared to CD. The level of IL-23 depended on the severity of both pathologies (p &lt; 0.05), which is confirmed by the established correlations between the level of IL-23 and the endoscopic activity index (r = +0.347; p = 0.005) and the Mayo index (r = +0.295; p = 0.020) in UC. Quantification of serum IL-17 levels in patients with IBD may be a useful additional criterion for the differential diag­nosis between UC and CD, and IL-23 may be a promising clinical marker for determining the severity of the disease.