In the complex cytokine landscape of both the healthy and the diseased gastrointestinal mucosa, TNF is an important IBD-associated proinflammatory cytokine (Murch et al., 1993; Breese et al., 1994; Nanki et al., 2020), and IL17 modulates the effect of other cytokines (Amatya et al., 2017). Here, IL17A is linked to inflammatory bowel disease.