IL17A and inflammatory bowel disease: There are growing evidences that Th17‐related cytokine IL‐17 has a highly pathogenic role in the IBD pathogenesis, while Treg‐related cytokine IL‐10 is an immunosuppressive cytokine that protects humans and mice from IBD (Geuking et al., 2011; Leppkes et al., 2009; Round & Mazmanian, 2010).