Elevated plasma levels of Th17-related cytokines are associated with increased risk of atrial fibrillation.

We performed a matched case-control study using a propensity score matching, to assess the association of Th17-related cytokines, including interleukin (IL) 17A (IL-17A), IL-17F, IL-21, IL-22 and IL-6, along with interferon-γ (IFN-γ), IL-10, IL-9, and IL-4, with the risk of AF. A total of 336 patients with AF were matched 1:1 with patients without AF. Plasma levels of cytokines were measured using Luminex xMAP assays. The plasma levels of all examined cytokines were significantly higher in AF patients than controls (P < 0.05), and these cytokines were highly correlated with each other (P < 0.01). A multivariate conditional logistic regression analysis showed that elevated plasma levels of IL-17A, IL-17F, IL-21, IL-22, IFN-γ, IL-10, IL-9 and IL-6 were significantly associated with AF risk independently of potential confounders. There were no significant differences in plasma levels of examined cytokines between paroxysmal and chronic AF patients. IL-17A, IL-21, IL-10 and IL-6 levels were positively correlated with left atrial diameter; IL-17F level was negatively correlated with left ventricle ejection fraction among AF patients (P < 0.05). Elevated plasma levels of Th17-related cytokines were independently associated with increased an risk of AF; hence, Th17-related cytokines may be involved in the pathogenesis of AF.

Association of inflammatory factors with occurrence and recurrence of atrial fibrillation: a meta-analysis.

BACKGROUND: The role of circulating inflammatory factors in atrial fibrillation (AF) occurrence and recurrence remains inconclusive. METHODS: We conducted a meta-analysis of observational studies evaluating the association of inflammatory factors with AF risk, postoperative AF (POAF) occurrence after coronary artery bypass grafting (CABG) surgery, and AF recurrence after electrical cardioversion (EC) or catheter ablation. RESULTS: Increased C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-α were significantly associated with AF risk (standardized mean difference [SMD] [95% confidence interval (CI)]: 0.95 [0.72-1.18], 0.89 [0.64-1.15] and 2.20 [1.17-3.23], respectively). In subgroup analysis, CRP was significantly associated with persistent and permanent AF risk, but not with paroxysmal AF. Increased preoperative CRP and IL-6 were associated with greater risk of post-CABG AF (SMD [95% CI]: 0.28 [0.02-0.54] and 1.03 [0.03-2.04], respectively). Consistent significant associations between CRP and AF recurrence were found in both patient subgroups who underwent EC (SMD, 0.56; 95% CI, 0.36-0.76) and ablation (SMD, 0.48; 95% CI, 0.11-0.86). IL-6 was significantly associated with AF recurrence after ablation (SMD, 0.55; 95% CI, 0.25-0.85), but not with the recurrence after EC (SMD, 0.85; 95% CI, -0.26-1.95). CONCLUSION: Increased circulating inflammatory factors, such as CRP and IL-6, are associated with greater AF risk in general population and patients who underwent CABG, as well as with AF recurrence after EC or ablation. Future research is warranted to elucidate the roles of other inflammatory markers, such as white blood cell, IL-8, and transforming growth factor-ß1, in occurrence and recurrence of well-established different clinical subtypes of AF.