Of 38 detected cytokines, interleukin (IL)-18, epidermal growth factor (EGF), and tumor necrosis factor (TNF), were significantly higher in RA samples, with a non-significant increase in IL-12p(70) and no variation seen in other cytokines including RA-associated IL-1β, IL-6, or IL-15 (Fig. 3A–G). This evidence concerns the gene IL15 and rheumatoid arthritis.