TREM1 and Cowden disease: Notably, one of the pathways enhanced in IBD intestinal macrophages is that of TREM1, a receptor found on macrophages that is responsible for the intracellular amplification of inflammatory signaling.29 This condition is consistent with the single-cell RNA-seq results of the Chapuy et al21 study, which identified a proinflammatory myeloid group of cells in active CD colonic mucosa that were positive for TREM1.