Cytokine Expression in Helicobacter pylori-Associated Gastrointestinal Diseases: Insights from Ulcerative Colitis and Colon Cancer

Abstract Background: Helicobacter pylori ( H. pylori ) is one of the most common chronic bacterial infections worldwide, associated with gastritis, peptic ulcer, and stomach cancer. Both ulcerative colitis (UC) and colon cancer (CC) are considered gastrointestinal diseases linked with chronic inflammation. Objective: the current study aimed to investigate the prevalence of H. pylori infection with cytotoxic-associated gene A (CagA) status in CC and UC patients and evaluate the cytokine expression of interleukin-21 (IL-21) and interleukin-23 (IL-23) in both groups to explore their potential role in H. pylori -associated pathogenesis. Materials and Methods: This is a cross-sectional study of 88 Iraqi patients, including 57 males and 31 females, aged between 45 and 70 years, who were recruited for this study; the data were collected from three different groups: 30 patients with CC, 58 patients with UC, and 30 healthy controls (HCs) aged between 41 and 73 years, with normal mucosa and no H. pylori infection. H pylori detection was confirmed, and a biopsy was taken from all participants for immunohistochemistry staining to assess IL-21 and IL-23 expression. A blood sample for serum extraction was also performed for H. pylori -CagA immunoglobulin G antibodies analysis using an enzyme-linked immunosorbent assay test. Results: The prevalence of H. pylori was more than half (60.34%) in UC and also high (70%) in CC patients, with no infection in HC. The prevalence of positive serum CagA level revealed that 100% H. pylori -positive CC cases and approximately 51.43% H. pylori -positive UC patients. The mean IL-21 and IL-23 expression was significantly different ( P = 0.0001) between all studied groups. The expression level of these cytokines was shown to be higher in H. pylori -positive CC followed by H. pylori -positive UC compared to other groups. The H. pylori -negative UC also showed increased expression of IL-21 and IL-23, as compared to HC. A significant positive correlation between the two cytokines was observed in H. pylori -infected patients and H. pylori -CagA-positive patients. Conclusion: An influential role in modulating immune responses was followed by the pro-inflammatory cytokines during H. pylori and H. pylori -CagA-positive infection, giving the importance of focusing on CagA status in the pathogenesis of post-CC and post-colon UC.