Compared to the HC group, RA patients exhibited significantly elevated levels of IL-2 (P<0.001), IL-4 (P<0.001), IL-6 (P<0.001), IL-10 (P<0.001), IL-17 (P<0.001), IFN-γ (P<0.001), and TNF-α (P<0.001) (Table 3; Figure 2; Supplementary Table 2). Here, IL2 is linked to rheumatoid arthritis.