Relation between direct detection of Chlamydia pneumoniae DNA in human coronary arteries at postmortem examination and histological severity (Stary grading) of associated atherosclerotic plaque

Background-Numerous studies have suggested a link between Chlamydia pneumoniae infection, atherosclerosis, and coronary artery disease. However, it is still unclear whether C pneumoniae plays a causal role in the pathogenesis of these conditions. Accordingly, we have performed a systematic dissection of the 3 coronary arteries on 33 postmortem subjects and studied the relationship in individual artery segments between the presence of C pneumoniae DNA and the severity of associated atherosclerosis, Methods and Results-The prevalence of C pneumoniae DNA in arterial segments was determined by polymerase chain reaction (PCR) after controlling for the presence of PCR inhibitors. Atherosclerosis in each arterial segment was graded histologically with the Stary classification. C pneumoniae was detected by PCR in 78.8% of subjects, but there was no association between the presence of this DNA and cause of death or grade of atherosclerosis. When paired mild and severe atherosclerotic lesions within subjects were compared, mild lesions were as Likely to be positive for C pneumoniae as severe lesions, Conclusions-This study demonstrates that C pneumoniae can frequently be detected in atheromatous plaques in coronary arteries, However, its distribution did not correlate with severity or extent of disease.