Treatment of mice with an atherogenic diet containing 1.25% cholesterol, 0.5% cholic acid, and 16% fat for 3 weeks induced mononuclear leukocyte infiltration in the liver, hepatic steatosis, and increased expression of inflammatory genes such as MCP1, RANTES, and MIP2. Of note, toll-like receptor (TLR)4-deficient mice displayed 30% attenuation in hepatic injury enzymes, 50% reduction in leukocyte infiltration, and a fourfold reduction in chemokine expression [27]. The gene discussed is CCL2; the disease is fatty liver disease.