TNF and psoriasis: Moreover, the IL-17A level is associated with the disease activity of adult patients with dermatomyositis and polymyositis.[6] Etanercept, a TNF-α inhibitor, was the 1st biologic agent to enter the clinic, and it provides an effective treatment for the majority of patients with moderate to severe psoriasis.[7] Although Etanercept is also used to treat dermatomyositis, some reports have indicated that it can induce amyopathic dermatomyositis and polymyositis.[4,5,8]