IL17F and rheumatoid arthritis: In the RA group, IL-17F expression was significantly suppressed by adalimumab at 1 and 10 μg/mL, and IL-22 levels were significantly suppressed by in vitro pretreatment with etanercept at 1 μg/mL or adalimumab at 1 or 10 μg/mL (Figure 2A, and 2C).