TYK2 and inflammatory bowel disease: On the other hand, TYK2 mainly inhibits proinflammatory cytokines, and thus, selectively targeting TYK2 may be of greater potential therapeutic interest in immune-mediated diseases such as IBD, Therefore, it is speculated that selective avoidance of excessive inhibition of particularly JAK2 and JAK3 may result in a more optimal safety profile as compared with inhibiting all four JAKs (JAK1-3 and TYK2) using a pan-JAK inhibitor.