IL2 and atrial fibrillation: Results demonstrated that the level of IL-2 in the peripheral blood serum of patients with AF increased by 42.38% compared to that in the normal control group (0.9980 ± 0.03558 vs. 1.4210 ± 0.1163 pg ml−1, **p < 0.01, Figure 1A), suggesting that the increase in IL-2 levels in the peripheral blood serum of patients with AF may be related to the inflammatory changes caused by AF.