IL33 and inflammatory bowel disease: The IL-33 plays key role in activating ILC2s, which prevented the C. difficile-induced colitis in the mouse model (Figure 2).113 Furthermore, the study predicted that the dysregulation of IL-33 signaling via the decoy receptor sST2 in human CDI is associated with mortality.113 Frisbee et al. 113 also discussed the role of microbiota in the induction of IL-33 response as previous studies in germ-free murine IBD models detected reduced expression of IL-33 in chronic ileitis of the small intestine.