RETNLB and colitis: During colitis, the release of several proinflammatory mediators, such as IL-6, IL-18, IL-22, and RELMβ, has been shown to enhance the intestinal epithelial cells proliferation, induce the release of antimicrobial peptides and anti-inflammatory mediators and promote the mucosa wound healing [20,40,41,43,44,45,46].