Exposure of peritoneal macrophages to an inflammatory lipid reduces Klf4 and increases M1 mRNAs, the latter induced to a greater extent in Klf4(f/f);Lys-Cre macrophage, and absence of myeloid Klf4 augments atherosclerosis in ApoE-/- mice [28]. The gene discussed is APOE; the disease is atherosclerosis.