In mice with experimental colitis, TREM-1 is barely expressed on peripheral blood Ly6Chi monocytes47, and although in HFCD-fed Trem1+/+Apoe−/− mice TREM-1 expression was upregulated on all peripheral blood cell subsets, TREM-1 surface expression on Ly6Chi monocytes remained low. The gene discussed is APOE; the disease is colitis.