IL17A and polymyositis: The mRNA levels of IFN-γ (39.02 ± 6.86) and IL-17A (26.43 ± 5.49) were elevated, respectively, in the muscle tissue of PM patients compared with the controls (0.87 ± 0.35, 6.74 ± 3.87, respectively, P < 0.001) (Figures 4C,F).