Clinical significance of antibody against oxidized low density lipoprotein in patients with atherosclerotic coronary artery disease

OBJECTIVES This study was designed to establish the clinical significance of antibodies against oxidized low density lipoprotein (anti-Ox-LDL) titer in atherosclerotic coronary artery disease (CAD). BACKGROUND Oxidative modification of LDL, which plays a key role in the development of atherosclerosis, induces immunogenic epitopes in the LDL molecule, and the presence of anti-Ox-LDL has been demonstrated in human sera. METHODS Anti-Ox-LDL titer was measured by enzyme-linked immunosorbent assay in 108 patients who had angiographically verified CAD, and 31 patients who had chest pain but no significant CAD, as controls. RESULTS The anti-Ox-LDL titer was higher (p < 0.01) in patients with multivessel CAD (19.4 ± 10.1 AcU/ml, N = 68) than in the controls (9.8 ± 4.1). However, no significant difference was shown between the single-vessel CAD group (15.1 ± 6.4, N = 40) and the controls, or between the multivessel CAD group and the single-vessel CAD group. The titer was higher in patients with unstable angina (21.5 ± 11.8 AcU/ml, N = 20, p < 0.01), or in patients with acute myocardial infarction (23.1 ± 12.0, N = 20, p < 0.01) than in patients with stable-effort angina or old myocardial infarction (12.2 ± 8.6, N = 68). Multiple logistic regression analysis indicated that the anti-Ox-LDL titer most powerfully discriminated CAD patients from controls (odds ratio [OR]: 1.20, 95% confidence interval [CI]: 1.07–1.33, P = 0.0006) and acute coronary syndrome from chronic CAD (OR: 1.09, 95% CI: 1.04–1.14, P = 0.0008). CONCLUSIONS Serum anti-Ox-LDL titer not only can predict a presence of atherosclerotic CAD but also may be a marker of plaque instability. Low density lipoprotein oxidation may play an important role in the development of plaque instability.