IL26 and Crohn disease: Indeed, increased infiltration of IL-26-positive Th17 cells was found in the colon of Crohn’s disease patients (48) and elevated expression of IL-26 mRNA was observed in the colon of pediatric-onset ulcerative colitis (49) as well as in tonsils and Payer’s patches in response to microbial stimuli, thus suggesting a pivotal role in mucosal immunity for this cytokine (50).