When lipid peroxidation takes place in plasma low density lipoprotein (LDL), a lot of aldehydes-derived epitopes are generated. To explore the relationship between these aldehydes-derived epitopes on apolipoprotein B (apo B) and coronary heart disease (CHD), we used both antibody against 4-hydroxynonenal (HNE)-derived epitopes and antibody against apo B to establish a sandwich enzyme-linked immunoassay (ELISA). The sera from 160 normal controls as well as from 103 patients with CHD were tested by ELISA for the expression of HNE-derived epitopes on apo B. The measurements showed that the mean expression of HNE-epitopes in the patients with CHD (183.5 +/- 63.6 mg/L, n = 103) was higher than that of normal controls (133.3 +/- 47.5 mg/L, n = 160). The difference of the expression of HNE-epitopes on serum apo B between the patients and normal controls was statistically significant. The results analysed by a multiple regression demonstrated that the expression of HNE-epitopes, levels of LDL-cholesterol and age were positively related to CHD, while the levels of HDL-cholesterol and female were negatively related to CHD. Thus, it was proven for the first time that the enhanced expression of HNE-epitopes on apo B might be an independent risk factor of CHD.