Frequency of CD4+CD161+ T Cell and Interleukin-10 Expression in Inflammatory Bowel Diseases

Mucosal immune dysregulation associated with T cells plays a critical role in the development of inflammatory bowel diseases (IBD). However, the definite significances of these cells in IBD still remain unclear. Therefore, we investigated the population and expression of CD4⁺CD161⁺ T cells in the colonic lamina propria mononuclear cells (LPMCs) in patients with IBD by analyses using flow cytometry and immunohistochemistry. Interleukin-10 (IL-10) mRNA levels in both LPMCs and CD4⁺ T cells in lamina propria (LP-CD4⁺ T cells) were measured using a real-time quantitative reverse transcription-polymerase chain reaction. IL-10 production was investigated with immunohistochemistry. The results revealed that the population of CD4⁺CD161⁺ T cells was significantly decreased in active ulcerative colitis (UC) compared with inactive UC (P < 0.05). The CD4⁺CD161⁺ T cell population was inversely correlated with disease activity in patients with UC (r = -0.6326, P = 0.0055), but there was no significant correlation in those with Crohn's disease. Over-expression of IL-10 mRNA in both LPMCs and LP-CD4⁺ T cells were detected in active UC. Immunohistochemistry revealed decreased frequency of CD161⁺ cells and increased IL-10 positive cells in active UC. The frequency of CD4⁺CD161⁺ T cells and IL-10 expression was supposed to be associated with the pathological status of mucosal immunoregulation in IBD.