Elevated expression of interleukin-21 and its correlation to T-cell subpopulation in patients with ulcerative colitis.

Objective: To investigate the expression of interleukin-21 (IL-21) and its correlation to T-cell subpopulation including Th1, Tc1 and Th17 cells in Ulcerative colitis (UC). Material and methods: We examined the expression of IL-21, IL-17 and IFN-γ in UC patients and controls by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Results: We found that IL-21 was expressed on CD3+CD8-T cells by flow cytometry. Plasma IL-21 level and the percentage of CD3+CD8-IL-21+ T cells were significantly elevated in UC patients compared to controls. The percentage of CD3+CD8-IL-17+ T (Th17), CD3+CD8-IFN-γ+ T (Th1) and CD3+CD8+ IFN-γ+ T (Tc1) cells was also significantly increased in UC patients. Moreover, we found a significant positive correlation between CD3+CD8-IL-21+T cells and Th17 cells. Conclusions: Elevated IL-21 and its positive correlation to Th17 cells may play a role in the pathogenesis of UC. [ABSTRACT FROM AUTHOR]