IL17A and polymyositis: Therefore, in the present study, we examined the expression of molecules in the TLR4 pathway and the changes of the expression of IFN-γ and IL-17A in 22 PM patients and a PM animal model, treated the mice with TLR4 antagonist TAK-242, and attempted to provide a full view of the effects of the TLR4 signal by regulating IFN-γ and IL-17A on the development of PM pathology.