Traditionally recognized risk factors for atherosclerosis are not presented in 50% of patients with ischemic heart disease. Chronic inflammation with low pathogenic agents with slightly, or no signs of inflammation is the mainstay of atherosclerosis and could be triggered by an infectious agent, most commonly by Chlamydia pneumoniae.

Immunostaning of 33 Chlamydia pneumoniae-positive and 30 Chlamydia pneumoniae-

negative quadriple arterial sets were examined for protective Sp110, and atherogenic HSP60 markers, as well as for TNF-α which is inflammatory marker affected by both of them.

The Chlamydia pneumoniae-negative deceased subjects were statistically significantly older and their BMI was significantly lower. The results showed that age, hypercholesterolemia, diabetes, arterial hypertension and BMI were negatively correlated with Chlamydia pneumoniae-positivity, while no significant relationship was found between Chlamydia pneumoniae-positivity and a positive family history of cardiovascular diseases, as well as smoking. Significantly higher presence of Sp110 in Chlamydia pneumoniae-negative group versus significantly higer presence od HSP60 in Chlamydia pneumoniae-positive group. Chlamydia pneumoniae-negative plaques showed higher TNF-α expression; difference is present for all arteries examined except the Willis circle.

This study may provide a model for further understanding the mechanisms of Chlamydia pneumoniae atherogenesis and evaluating chlamydial intervention strategies for preventing the advancement of atherosclerotic lesions enhanced by bacterial infections.