[Oxidatively modified lipoproteins and their antibodies in patients with antiphospholipid syndromeand systemic lupus erythematosus]

Abstract

The antiphospholipid syndrome (APS) with its typical clinical manifestations of recurrent thrombosis and fetal loss is biochemically defined by the presence of circulating antiphospholipid antibodies (aPL). The disease pattern has raised special interest as a possible link between autoimmunity and atherosclerosis. aPL, oxidized low density lipoproteins (oxLDL), and antibodies to oxLDL (Anti-oxLDL) are suggested to play an important role in atherogenesis. In the present study we compared the serum levels of oxLDL and Anti-oxLDL in APS patients (20 subjects with primary APS; 14 subjects with secondary APS) and nonAPS subjects (24 phenotypically healthy controls samples and 12 patients with systemic lupus erythematosus [SLE]) and investigated associations of the above mentioned parameters with the intima-media thickness (IMT), a clinical surrogate parameter of atherosclerosis.SLE patients with and without APS showed significantly increased levels of Anti-oxLDL as compared to the controls group (p = 0.038 and p = 0.007, respectively). In contrast, oxLDL levels were not significantly different between the controls group and patients. The Anti-oxLDL levels correlated significantly with anticardiolipin (p = 0.002) and beta(2)-glycoprotein I antibodies (p < 0.048), both from IgG isotype. Only SLE patients without APS revealed a significantly elevated production of reactive oxygen species indicating an increased proatherogenic oxidative stress in the circulation (p < 0.002). In the patient groups, the circulating levels of oxLDL and Anti-oxLDL showed no association with atherosclerosis as estimated by IMT. In conclusion, our experimental data do not support the concept of oxidative stress-induced accelerated atherosclerosis in APS patients.