Atherosclerosis is now recognized as an inflammatory/immunomodulatory reaction to the presence of oxidized low-density lipoproteins within the arterial wall, often times in the setting of such risk factors as family history, hypercholesterolemia, high blood pressure, diabetes mellitus and smoking. The progression to high-risk lesions such as thin-fibrous cap atheromas results in an increased risk of sudden death, acute myocardial infarction and ischemic stroke. The interplay of macrophages, T lymphocytes and mast cells play a central role in both the development but more importantly in the progression of coronary and carotid artery disease to high-risk phenotypes.