Autoantibodies against oxidised low density lipoproteins in patients with coronary disease

OBJECTIVES Evidence has been obtained indicating that oxidation of low-density lipoproteins (LDL) plays a relevant role in the pathogenesis of atherosclerosis and it has been proposed that, due to the antigenic properties of oxidized LDL, the anti-oxLDL antibody titre could represent a useful index of in vivo LDL oxidation. METHODS Sixty-nine control subjects and 64 patients scheduled for selective coronary revascularization were investigated before surgery. RESULTS The coronary disease patients had a higher level of total plasma cholesterol, LDL cholesterol and triglycerides, and a lower level of HDL cholesterol. Plasma anti-oxLDL antibody titre was measured as the ratio of antibody binding to CuSO4-oxidised LDL versus native LDL. The antibody ratio was higher in coronary patients as compared with control subjects (1.56 +/- 0.5 vs 1.0 +/- 0.3, p < 0.01). A ratio higher than 1.34 (mean of controls +/- one standard deviation) was present in 60% of the coronary patients. Subclass analysis indicated that the presence of diabetes mellitus and hypercholesterolaemia (but not of hypertension, generalized arteriosclerosis, myocardial infarction and cigarette smoking) increased the anti-oxLDL antibody ratio to 1.72 +/- 0.4 and 1.68 +/- 0.3 respectively. CONCLUSION The results obtained indicate that a) a high titre of anti-oxLDL antibodies is present in plasma of patients with coronary atherosclerosis, b) in these patients LDL oxidation takes place in vivo and probably plays a critical role in the development and progression of atherosclerosis.