Background: Seroepidemiological, pathological and animal studies suggest that chronic infection with Chlamydia pneumoniae (Cp) may directly impact the development or progression of atherosclerosis and coronary heart disease. The aim of the present study was to determine the seroprevalence of Cp infection and markers of systemic inflammation in patients undergoing routine coronary artery examination and prior to heart revascularization.
Material and methods: The research involved 76 patients with severe CAD and 81 control patients with normal coronary circulation confirmed by coronary angiography. The presence of serum IgG and IgA antibodies to Cp and plasma interleukin-8 (IL-8) levels was measured by EIA test. Furthermore, the levels of plasma C-reactive protein, fibrinogen, total cholesterol, and triglycerides were measured in all patients.
Results: Seropositivity to Cp was found in 60.5% for IgG and in 61.8% of cases for IgA with CAD patients, as compared to 26.0% and 29.5% in the controls (p<0.001), respectively. The levels of Interleukin-8, plasma fibrinogen, total cholesterol and triglycerides were significantly higher (p<0.001) in the CAD group, while C-reactive protein tended to have a higher value in patients with atherosclerosis than in the control group, although the difference was not significant.
Conclusions: Cp infection significantly increases the risk of CAD, usually requiring coronary bypass surgery or percutaneous coronary intervention as effective measures. It may also modify the levels of serum lipids, CRP and fibrinogen, increasing the risk of atherosclerosis. The strong correlation between the elevated IgG and IgA titers of Cp in patients treated with angioplasty or surgery may impact their follow-up; this issue requires further investigation.