Chronic infections, including Chlamydia pneumoniae, cytomegalovirus and Helicobacter pylori may be one of the risk factors for coronary artery disease (CAD). To document whether chronic infection may be associated with coronary artery disease, various inflammatory markers were analyzed in Korean patients with CAD.

The patients who underwent diagnostic coronary angiography (CAG) were divided into two groups according to the results of CAG: the patients with significant coronary lesions (Group I: n=126, M:F=99:27, 58.7±9.7 years) or the patients without coronary lesions (Group II: n=58, M:F=30:28, 55.5±8.9 years). Serologic assays for the immunoglobulin G (IgG) titers to C. pneumoniae, CMV, H. pylori, and for inflammatory markers, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were performed.

There were no significant differences in the sero-positivity of three infections between two groups, but titer of IgG antibody against H. pylori was significantly higher in Group I than that in Group II (859.3±342.2 vs. 474.2±113.2 U/mL, p=0.02). After adjustment for age, sex and other cardiovascular risk factors, high titer of IgG antibody aganist H. pylori was independently associated with coronary artery disease (p=0.05). CRP and ESR were significantly elevated in group I (2.7±5.1 vs. 0.6±0.9 mg/dL, p=0.003, 23.2±26.7 vs. 12.7±15 mm/hr, p=0.006). Angiographic parameters were not related with the titer of infectious agents or inflammatory markers. The value of CRP was significantly different according to clinical severity (3.8±6.0 in acute myocardial infarction, 1.5±3.6 in unstable angina pectoris, and 0.4±0.3 mg/dL in stable angina pectoris, p<0.01). The value of ESR was also significantly different according to clinical severity (29.0±30.2 in acute myocardial infarction, 17.1±19.0 in unstable angina pectoris, and 12.1±17.6 mm/hr in stable angina pectoris, p<0.01).

Our results suggest that high titer of IgG antibody against H. pylori may be associated with CAD, and inflammation may play a significant role in the pathogenesis of acute coronary syndromes.