Increased levels of autoantibodies to cardiolipin and oxidised low density lipoprotein are inversely associated with plasma vitamin C status in cigarette smokers

In this study we have measured circulating levels of autoantibodies to cardiolipin and oxidised low-density lipoprotein (ox-LDL) and correlated these with plasma concentrations of the anti-oxidant nutrients vitamin C, vitamin E and beta-carotene, in a group (79) of asymptomatic, male cigarette smokers and in non-smoking control subjects. Cigarette smoking, a well-known risk factor for development of atherosclerosis, was found to be associated with moderately elevated levels of autoantibodies to both cardiolipin and ox-LDL. Increased levels of these autoantibodies were most evident in the older smokers (> 30 years) and were significantly and inversely corrrelated wtih plasma vitamin C, but not with vitamin E or beta-carotene. Absorption studies designed to investigate the specificity of these autoantibodies demonstrated a high degree of cross-reactivity of cardiolipin antibodies with ox-LDL, while antibodies to the oxidatively modified lipoprotein tended to be specific for this antigen. These findings suggest that cigarette smoking promotes formation of autoantibodies to both cardiolipin and ox-LDL and that these may be involved in the initiation and/or perpetuation of athersclerosis. Dietary intake of vitamin C may be a determinant of susceptibility to development of this cardiovascular disorder.