The relationship between Chlamydophila pneumoniae IgG titer and coronary atherosclerosis.

BACKGROUND The role of Chlamydophila pneumoniae (CP) in the progression of atherosclerosis is controversial. Also no sufficient angiographic study is available about the impact of CP infection on severity and intensity of coronary atherosclerosis. We investigated the relation between CP IgG antibody titers and severity and intensity of coronary atherosclerosis METHODS The study population consisted of 516 consecutive patients who underwent a coronary angiography. The group included 353 patients who had coronary artery disease; a control group included 163 subjects with angiographically proven normal coronary arteries. Chlamydophila pneumoniae IgG antibody titers were measured by an enzyme immunoassay method in all patients. Gensini scores and extent scores were used to evaluate the angiographic extent and severity of atherosclerosis. RESULTS The mean value of IgG antibody titer was 44.3 +/- 28.8 IU/mL in the patients and 39.8 +/- 27.4 IU/mL in the control group (p = 0.14). There was no statistically significant correlation between the Gensini scores, extent scores and CP IgG titers (Gensini score: r = +0.103, p = 0.07, extent score: r = +0.110, p = 0.31). When we grouped the patients as high (> 50 IU/mL) and low (< 50 IU/mL) IgG antibody titers, the number of diseased coronary arteries was higher in patients with high IgG antibody titers (respectively: 2.6 +/- 1.1 vs. 2.2 +/- 0.8, p = 0.01). While the Gensini score was significantly higher in patients with high IgG antibody titers (7.5 +/- 4.0 vs. 6.17 +/- 4.0, p = 0.01), the extent score did not change with IgG titers (29.8 +/- 15.9 vs. 25.8 +/- 15.4, p = 0.08). CONCLUSIONS In our study, we investigated the relation between CP infection and coronary atherosclerosis and found that CP IgG antibody titers are associated with the severity of coronary stenosis at higher antibody levels. However, there is no association between CP antibody titers and clinical presentation of coronary artery disease. We suggest that CP has limited effect on coronary atherosclerosis.