Serum anti-malondialdehyde-acetaldehyde IgA antibody concentration improves prediction of coronary atherosclerosis beyond traditional risk factors in patients with rheumatoid arthritis

Patients with rheumatoid arthritis (RA) have increased atherosclerosis; oxidative stress may be a contributor. Oxidative stress produces immunogenic malondialdehyde-acetaldehyde (MAA) protein adducts and anti-MAA antibodies are detectable in human serum. We hypothesized that anti-MAA antibody concentrations are associated with coronary atherosclerosis in RA patients. Serum concentrations of anti-MAA antibodies (IgA, IgG, and IgM) were measured in 166 RA patients using ELISA cross-sectionally. Relationship between anti-MAA antibody concentrations and cardiovascular and metabolic measures and predictive accuracy of anti-MAA antibodies for presence of coronary artery calcium (CAC) and high CAC (≥ 300 Agatston units or ≥ 75^th percentile) were assessed. Only serum IgA anti-MAA antibody concentration was associated with increased CAC, insulin resistance, and decreased high-density lipoprotein particle number. When added as an interaction term with ACC/AHA 10-year risk score plus high-sensitivity C-reactive protein, IgA anti-MAA antibody concentration improved the C-statistic for prediction of any CAC and high CAC compared to ACC/AHA 10-year risk score plus hs-CRP alone. IgA anti-MAA concentration is associated with multiple cardiovascular risk factors and modifies the relationship between ACC/AHA 10-year risk score and CAC in RA patients. IgA anti-MAA concentration could assist in prediction of atherosclerotic CVD and risk stratification when added to standard measures of cardiovascular risk.