The major hallmark of Th17 cells is the production of cytokines such as IL-17 and IL-22 as well as the recruitment and activation of neutrophils, and they have been described to play important roles not only in host defence against microbial infections but also in tissue inflammation during autoimmunity regarding liver disease; initial studies in humans and mice indeed also revealed activated Th17 cells and Th17-related cytokines in various liver diseases. The gene discussed is IL22; the disease is liver disorder.