Background and purpose: Autoantibodies against antigens in oxidized low-density lipoprotein are common in people; experimental studies suggest that these immune responses have a functional role in the disease process. The aim of this study was to evaluate the relationship between the immune response against one defined oxidized low-density lipoprotein antigen, the aldehyde-modified peptide corresponding amino acids 3136 and 3155 (MDA-p210) in apolipoprotein (apo) B-100, and progression of carotid intima media thickness (IMT).
Methods: IgM and IgG against MDA-p210 were determined by enzyme-linked immunosorbent assay at baseline and after 12 months of treatment with placebo, metoprolol, fluvastatin, or metoprolol/fluvastatin in 751 individuals participating in the BCAPS. Carotid IMT was assessed by ultrasonography at baseline and after 18 and 36 months of treatment.
Results: Antibody levels did not change in response to treatment, but high baseline MDA-p210 IgM levels were associated with a more rapid progression of carotid disease both at 18 (r=0.09, P<0.05) and 36 months (r=0.12, P<0.005). At 36 months, the difference in IMT progression rate per year between those with high MDA-p210 IgM levels and those with low was 0.011 mm (95% CI=0.005 to 0.018 mm, P<0.0001). Treatment with fluvastatin markedly decreased the progression of IMT among subjects with high but not with low MDA-p210 IgM levels. There was no association between MDA-p210 IgG and carotid IMT progression.
Conclusions: IgM against the aldehyde-modified peptide corresponding amino acids 3136 and 3155 in apo B-100 is common in subjects with asymptomatic carotid disease, and high levels are associated with a more rapid progression of carotid IMT. The observation that the effect of fluvastatin was restricted to subjects with high MDA-p210 IgM levels may reflect the increased rate of disease progression in this group.