Common community infections and the risk for coronary artery disease and acute myocardial infarction: evidence for chronic over-expression of tumor necrosis factor alpha and vascular cells adhesion molecule-1.

Background: Although several common community infections have been associated with the risk for coronary artery disease (CAD), their role in the development of acute myocardial infarction (AMI) is still unclear. We examined the prevalence of IgG and IgM (or IgA) antibodies against common infections such as HSV, Hepatitis A (HAV), Helicobacter pylori (HP), cytomegalovirus (CMV) and Chlamydia pneumoniae (CP), in CAD and AMI patients, and their relationship with pro-atherogenic inflammatory molecules.
Methods: A total number of 337 subjects were included in this study: 150 patients with angiographically documented stable CAD, 138 patients admitted with AMI and 49 healthy individuals. Serum IgG and IgM against HAV, CMV and HSV, IgG against HP and IgG/IgA against CP were determined in all participants. Serum tumor necrosis factor alpha (TNF-alpha) and soluble vascular cells adhesion molecule (sVCAM-1), were determined by ELISA.
Results: Patients with CAD were more likely to have anti-HAV IgG (94.4%), anti-HSV IgG (97.2%) and anti-HP IgG (55.1%) compared to healthy individuals (70.8%, 89.6% and 39.6% respectively, p<0.05 for all). In multivariate analysis, anti-HAV IgG was an independent predictor of CAD (beta(SE): 0.187(0.075), p=0.015). Among the CAD patients, the presence of anti-CP IgA was more frequent in those admitted with AMI (39%) compared to those with stable CAD (21%, p<0.05). Finally, both patients and controls had significantly higher levels of sVCAM-1 and TNF-alpha in the presence of anti-HAV IgG, compared to those without anti-HAV IgG (p<0.05 for all).
Conclusion: Past infections with HAV, HSV and HP are associated with higher risk for coronary atherosclerosis, while the presence of anti-HAV IgG is also associated with higher levels of TNF-alpha and sVCAM-1. Furthermore, the presence of recent infection by CP is associated with higher risk for AMI among CAD patients. These findings are important since they demonstrate that past HAV, HSV and HP infections may affect cardiovascular risk, while recent CP infection may be implicated in the triggering of AMI among CAD patients.