In active IBD, high numbers of IL-22 producing cells (Geremia et al., 2011) and elevated levels of IL22 mRNA and IL-22 protein have been documented in several independent studies (Brand et al., 2006; Pelczar et al., 2016; Feagan et al., 2017; Nikolaus et al., 2017). This evidence concerns the gene IL22 and inflammatory bowel disease.