IL17A and multiple sclerosis: Interleukin-17 (IL-17) is produced by T helper (Th)-17 cells and has been reported to trigger tissue inflammation and damage in various chronic diseases (Liu et al., 2016), including hepatic inflammation and liver cirrhosis (Rong et al., 2009), inflammatory bowel disease, rheumatoid arthritis, and multiple sclerosis (Axtell et al., 2010).