Reduced serum levels of autoantibodies against monomeric C-reactive protein (CRP) in patients with acute coronary syndrome

IntroductionInflammation is pivotal in atherosclerosis. Minor C-reactive protein (CRP) response reflects low-grade vascular inflammation and the high-sensitivity CRP test with levels ≥ 3.0 mg/l predicts coronary vascular events and survival in angina pectoris as well as in healthy subjects. We and others recently reported autoantibodies against monomeric CRP (anti-CRP) in rheumatic conditions, e.g. systemic lupus erythematosus (SLE), and a connection between anti-CRP and cardiovascular disease in SLE has been suggested.Patients and methodsAnti-CRP serum levels were determined with ELISA in 140 individuals; 50 healthy controls and 90 patients with angiographically verified coronary artery disease of which 40 presented with acute coronary syndrome (ACS) and 50 with stable angina pectoris (SA).ResultsSignificantly lower anti-CRP levels were observed in ACS compared to SA and controls (p = 0.019). ACS patients, who had not been prescribed statins before their respective cardiovascular event, had lower anti-CRP (p = 0.049). BMI correlated directly to anti-CRP levels in cross section analysis (p = 0.043), but there was no association between anti-CRP and smoking or cholesterol.DiscussionIn ACS, it is plausible that ruptured plaques and inflamed tissue may be more prone to opsonization by monomeric CRP leading to consumption of anti-CRP. Hypothetically, surface-bound anti-CRP could thereby enhance the local inflammation in plaques.