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. Here, IL21 is linked to atrial fibrillation.