Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 51 12 2013 12 15 864 870 EN Morteza Izadi Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Mozhgan Fazel International Travel Medicine Center of Iran, Tehran, Iran Mohsen Akrami International Travel Medicine Center of Iran, Tehran, Iran. Seyed Hassan Saadat International Travel Medicine Center of Iran, Tehran, Iran. Bahram Pishgoo International Travel Medicine Center of Iran, Tehran, Iran. Mohammad Hassan Nasseri International Travel Medicine Center of Iran, Tehran, Iran. Hossein Dabiri Department of Medical Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Reza SafiAryan Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Ali Akbar Esfahani Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Ali Ahmadi Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Davood Kazemi-Saleh Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Mohammad Hassan Kalantar-Motamed Health Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Saeed Taheri Dr Taheri Medical Research Group, Tehran, Iran. 2015 10 11 An association between Chlamydia pneumoniae (C. pneumoniae) and cardiovascular disease has been demonstrated. In this study, we aimed to study this potential relationship in 105 Iranian patients. Coronary artery specimens from 105 Iranian patients undergoing CABG were analyzed by PCR method for C. pneumoniae. Serological evaluation for C. pneumoniae IgG and IgM was performed using ELISA. 53 specimens from mamillary artery were also investigated. C. pneumoniae PCR test result was positive for 23 (21.9%) of patients with coronary artery atherosclerosis, but none of the specimens from the mamillary artery was positive for C. pneumoniae when it was evaluated by the PCR (P<0.001). Coronary artery disease patients with and without a history of unstable angina or myocardial infarction were comparable in C. pneumoniae PCR test positive rates (P=0.618). Relevance of IgG and IgM positivity were also studied by correlating it to the study parameters, but no difference was found. CRP was significantly higher in the IgM positive group (P<0.001). A significant proportion of coronary atherosclerotic plaques are infected with C. pneumoniae while no infection was found in the normal mamillary artery specimens. No association was found between acute coronary syndromes and serological and PCR positivity. Further prospective randomized controlled studies with large patient population are needed to confirm our findings. https://acta.tums.ac.ir/index.php/acta/article/view/4332 https://acta.tums.ac.ir/index.php/acta/article/download/4332/4541