Elevated levels of IL-2 and IL-21 produced by CD4+ T cells in inflammatory bowel disease

CD4+ T cells are considered as a subset of cells that play a pivotal role in the development of inflammatory bowel disease (IBD). The aim of this study was to assess the levels of interleukin (IL)-2, IL-21 and their receptors produced by CD4+ T cells in patients with inflammatory bowel disease. Thirty-two patients with ulcerative colitis (UC) and mean age of 37.93±10.37 years, as well as 22 patients with Crohn’s disease (CD) and mean age of 37.04±10.44 years, were studied. The healthy controls (HC) included 31 subjects with a mean age of 36.7±10.48 years. Peripheral blood mononuclear cells (PBMCs) were isolated from all the participants. The CD4+ T cells were isolated and the expression of IL-2 and IL-21 and also their receptors were examined by flow cytometry. The level of IL-2+ cells was significantly increased in UC patients compared with HC (40.71±6.04 vs 37.24±6.54, respectively, p=0.04). The level of IL-21+ cells was also significantly elevated in CD patients compared with HC (4.44±1 vs 3.83±0.74, respectively, p=0.02). Furthermore, we found a significant positive correlation between clinical activity index (CAI) and IL-21+ cells. According to the results, we hypothesize that the elevated level of IL-2+ and IL-21+ T cells and a positive correlation between IL-21+ cells with CAI in UC patients may contribute to the pathogenesis of disease. Moreover, the assessment of cells producing such cytokines constitutes a potential diagnostic and therapeutic strategy for IBD.