Background: Cytomegalovirus (CMV) and Chlamydia pneumoniae (C. pneumoniae) antigens and DNA sequences have been demon- strated in atherosclerotic plaques by several investigators. Most significantly, CMV DNA was found both in atherosclerotic lesions as well as in uninvolved areas of aortas and carotid artery, whereas C. pneumoniae was mostly detected in advanced carotid atherosclerotic lesions. Methods and results: Atherosclerotic plaques removed from seventeen patients during carotid endarterectomy were analysed for the simultaneous presence of CMV and C. pneumoniae DNA sequences using polymerase chain reaction (PCR). Of the seventeen samples, nine (53 %) were positive for CMV DNA sequences and seven (41 %) contained C. pneumoniae DNA sequences. Four samples (24 %) were positive for both CMV and C. pneumoniae DNA. CMV DNA or C. pneumoniae DNA was detected in 12 (71 %) of 17 carotid plaques and 2 additional patients had high titers of antibodies to CMV. CMV DNA and C. pneumoniae DNA were found in the same tissue specimens in 4 (24 %) patients. Conclusions: These results present evidence that CMV DNA and/or C.pneumoniae DNA can be detected in 71 % of carotid atherosclerotic plaques and in some instances DNA of both agents in the same tissue. The possible pathogenetic role of these agents in the initiation or promotion of the development of atherosclerotic plaques deserves increased attention.

        Key words: CMV, Chlamydia pneumoniae, atherosclerosis, cardiovascular disease