Chlamydia pneumoniae infection in patients with carotid artery disease

Abstract

Background. Infection with Chlamydia pneumoniae, a common human respiratory tract pathogen, has been recently associated with cardiovascular syndromes, such as atherosclerosis, myocardial infarction and stroke. According to the literature data significantly high percentage of CAD patients exhibited serological markers of chronic Chlamydia pneumoniae infection. Chlamydia pneumoniae DNA and antigens were also detected (using variety of methods) in carotid arteries atherosclerotic plaques. The aim of the study was to evaluate the frequency of Chlamydia pneumoniae infection in CAD patients by measuring specific serum IgG, IgM and IgA levels and by detection of Chlamydia pneumoniae DNA in carotid atherosclerotic plaques.
Material and methods. 28 patients operated for CAD (8 female, 20 male; mean age 64.5 years) and 20 control subjects matched for age and sex (4 female, 16 male) without clinical signs and symptoms of cardiovascular and pulmonary disease were enrolled in the study. Microimmunofluorescence method was applied to evaluate the level of anti-Chlamydia pneumoniae IgG, IgA and IgM. Chlamydia pneumoniae micro-IF test (Labsystem) was used. Nested PCR was used for Chlamydia pneumoniae DNA detection in atherosclerotic plaques, obtained during carotid endartherectomy. The results were evaluated by means of STATISTICA software programme and considered statistically significant when was less than 0.05 (p < 0.05).
Results. Serologic markers of chronic Chlamydia pneumoniae infection were detected in 22 of 28 (78.6%) patients and in 6 of 20 (30%) healthy controls. In 36.4% (8/22) of patients with serologic markers of chronic Chlamydia pneumoniae infection we observed high titers of specific IgG and IgA, which can indicate reinfection or exacerbation of chronic infection. Interestingly, all patients in this group presented to have TIA symptoms. Chlamydia pneumoniae DNA was present in carotid atherosclerotic plaques obtained from 17 (60.7%) patients.
Conclusions. Serological signs of chronic Chlamydia pneumoniae infection occur statistically more frequent in CAD patients compared to healthy controls. Active Chlamydia pneumoniae infection is associated with TIA symptoms. There is an urgent need of standardization of PCR methods detecting DNA Chlamydia pneumoniae in atherosclerotic plaques.