IL15 and dermatomyositis: Zhong et al. investigated the IL-15 and IL-15Rα expression in skeletal muscle of patients with PM and DM after treatment [64], and they observed that IL-15/IL-15Rα expression was correlated with clinical findings: patients with a high number of IL-15-expressing cells in muscle tissue after immunosuppressive treatment had less improvement in muscle performance, which might indicate that IL-15 has a role in causing muscle weakness.