The Th17 cell is a CD4+ T cell subpopulation distinct from IFN-γ-producing Th1 and IL-4-producing Th2 and is characterized by secreting IL-17, a proinflammatory cytokine [54]; many studies over the past decade have been focusing on IL-17 and Th17 cell participation in the inflammatory process of the autoimmune diseases. The gene discussed is IL17A; the disease is autoimmune disease.