Abstract:Objective To investigate the correlation between Th17 cells and cytokines in peripheral blood of patients with idiopathic atrial fibrillation (AF). Methods Totally 80 patients with AF admitted to department of cardiology in our hospital were enrolled, including 34 patients with paroxysmal AF (PAF) and 46 patients with chronic AF (CAF), and the other 80 persons with the same age in the health examination were the control group. Flow cytometry was used to detect the percentage of peripheral blood mononuclear lymphocyte (PBMCs) Th17 cells. The levels of serum interleukin IL-17, IL-6, IL-22 and matrix metalloproteinase -9 (MMP-9) were detected by ELISA. The differences between the control group and the AF group were compared, and the correlation analysis was made. Results There were no significant difference in baseline data among PAF group , CAF group and control group (P > 0.05). The percentage of Th17 cells in the PAF group and CAF group were higher than that in the control group (P < 0.05), and the percentage of Th17 cells in the CAF group were higher than that in the PAF group (P < 0.05). Compared to control group, the levels of IL-17, IL-6, IL-22 and MMP-9 were higher in PAF group and CAF group (P < 0.05). The levels of IL-17, IL-6 and MMP-9 in the CAF group were higher than that in the PAF group (P < 0.05). The percentage of Th17 cells in AF patients was positively correlated with left atrial diameter (LAD) and negatively correlated with left ventricular ejection fraction (LVEF) (P < 0.05). Conclusions The percentage of Th17 cells and the levels of IL-17, IL-6 and IL-22 in peripheral blood of patients with idiopathic AF are increased and related to the process of AF and the level of myocardial fibrosis.