Concentration of anti-7-ketocholesterol antibodies in patient sera after heart transplantation.

Oxidized low-density lipoproteins (ox-LDL) have been shown to be strongly atherogenic and immunogenic in experimental animals and in humans. Autoantibodies against ox-LDL and its various epitopes have been detected in sera and in atherosclerotic lesions. LDL oxidation may also lead to generation of oxidized derivatives of cholesterol (eg, 7-ketocholesterol [7-ketoCh]), which are characterized by high levels of cytotoxicity, muta- and carcinogenicity, as well as immunosuppressive effects and probable immunogenic properties. The aim of this study was to quantify autoantibodies to 7-ketoCh in sera from patients after orthotopic heart transplantation (OHT). IgG antibodies were measured in sera from 81 patients after OHT and 73 healthy volunteers using and enzyme-linked immunosorbent assay (ELISA) method. For the antigen we used 7-ketoCh hemisuccinate conjugated to bovine serum albumin. Anti-7-ketoCh antibodies were detected in all examined sera. Their concentrations were significantly higher among OHT patients than the control group, namely, 109.0 +/- 109.7 vs 53.5 +/- 20.0 U/mL (P < .005). Also, we observed a direct relationship between antibody concentration and time after OHT. Our results showed that the low molecular product of LDL oxidation, 7-ketoCh, was immunogenic possibly playing a role in the progression of atherosclerosis among OHT patients.