TREM1 and inflammatory bowel disease: In both mouse models and human ex vivo models of IBD, the blockage of TREM1 seems to dampen the immune response.33, 34 Furthermore, the expression of key M1 genes involved in T-cell recruitment and activation (CXCL9, CXCL10, and CXCL11 along with CD40) was also increased in IBD macrophages, validated by qPCR and immunohistochemistry (CXCL9 and CD40).