IL26 and Crohn disease: This association is similar to the role that IL-26 plays in other inflammatory diseases such as rheumatoid arthritis [19] – wherein IL-26 has been shown to be over-expressed and to generate pro-inflammatory cytokine production and Th17 cell induction – and Crohn's disease [29] – wherein IL-26 modulates intestinal epithelial cell proliferation and pro-inflammatory gene expression.