IL17A and Hepatitis: In addition, IL-17, which is produced by pro-inflammatory T helper 17 (Th17) cells, can promote liver inflammation and fibrosis by facilitating the production of IL-6, IL-1, and TNF-α by inflammatory cells and activating hepatic stellate cells to produce collagen type I (Meng et al., 2012; Harley et al., 2014).