These previous findings, in conjunction with our finding, suggest that appropriate IL-23p19 expression induced by activation of TLR2 may meet normal physiological needs to maintain intestinal homeostasis between gut microbes and inflammatory cytokines, while its excessive expression caused by NOD2 may be the major cause for disrupting the intestinal homeostasis and for the occurrence of IBD. Here, TLR2 is linked to inflammatory bowel disease.