TREM2 and inflammatory bowel disease: In the inflamed intestinal mucosa of inflammatory bowel disease (IBD) patients, TREM2 is mainly expressed on the surface of mature CD11c+ DCs and promotes the release of pro-inflammatory cytokines, such as TNF-α, IL-6, IL-1β, and IL-12p70, as well as the activation of T cells, thereby contributing to the progression of IBD (34).