Consistently, we and others have demonstrated that IL-10R and CX3CR1 deficiency in intestinal macrophages can cause intestinal inflammation and impaired oral tolerance, respectively4,44, and Trem1 upregulation in intestinal monocytes/macrophages during inflammation has been reported to promote production of proinflammatory mediators that amplify the inflammatory response in both, DSS and T-cell mediated colitis models, as well as in human IBD patients13,45,46. Here, TREM1 is linked to colitis.