IL-17 is a T cell-derived cytokine that includes a 6-member ligand (IL-17A~IL-17F) and five receptors (IL-17RA~IL-17RD and SEF). IL-17 is a proinflammatory cytokine produced mainly by activated T cells, which promotes the activation of T cells and stimulates the production of various cytokines such as IL-6 and IL-8 in epithelial cells, endothelial cells and fibroblasts. Granulocyte-macrophage stimulating factor (GM-CSF) and chemical stimulating hormone 1 and cellular adhesion molecule 1 (CAM-1), leading to inflammation.