en تخصصي Special پژوهشي Original article <div><strong>Background and Aims:</strong> Human T-lymphotropic virus type 1 (HTLV-1) is a member of retroviridae family that causes ATL and HAM/TSP. Many inflammatory diseases are associated with this virus, such as Sj&ouml;gren&#39;s syndrome, Hashimoto&#39;s thyroiditis, Uveitis and also Atherosclerosis. HTLV-1 performs in long latency period and can activate the immune responses in coronary vessels. Activated immune system produces inflammatory factors such as TNF-&alpha; cytokine that can increase Matrix Metalloproteinases as a main factor in patients with coronary artery diseases (CAD). We aimed to determine the relation between this virus infection and MMP-3 expression in Atherosclerosis patients.<br> <strong>Materials and Methods:</strong> 44 patients (13 individuals CAD+ HTLV-1+, 8 individuals CAD- HTLV-1+, 13 individuals CAD+ HTLV-1- &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;and 10 individuals CAD- HTLV-1-) were selected and MMP-3 gene expression was measured by Real-time polymerase chain reaction. <strong>Results:</strong> There was no significant correlation between MMP-3 gene expression and HTLV-1 expression level in HTLV-1-positive cardiac and Atherosclerosis patients.</div> <strong>Conclusions: </strong>Although the main risk factor in Atherosclerosis patients is MMP-3, despite our expectation, no significant correlation was observed in our statistical analysis within four examined groups (p&ge;0.05). This evaluation showed higher MMP-3gene expression but not significant in CAD+ HTLV-1+ group compared to CAD+ HTLV-1- group. The larger sample sizes may help to improve the outcome to reach a significant level. HTLV-1, MMP-3, TNF-α, Atherosclerosis, Real-time PCR 13 18 http://journal.isv.org.ir/browse.php?a_code=A-10-140-1&slc_lang=en&sid=1 Mina Mohammadhosayni mobinhuseyni@yahoo.com 10031947532846006715 10031947532846006715 No Department of Immunology, Faculty of Medicine, Shahed University, Tehran, Iran Fatemeh Hajighasemi hajghasemi@gmail.com 10031947532846006716 10031947532846006716 No Department of Immunology, Faculty of Medicine, Shahed University, Tehran, Iran Abdolrahim Rezaee RezaeeR@mums.ac.ir 10031947532846006717 10031947532846006717 No Inflammation and Inflammatory Diseases Division, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Farnaz Mozayani MozayaniF881@gmail.com 10031947532846006718 10031947532846006718 No Inflammation and Inflammatory Diseases Division, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Fatemeh Sadat Mohammadi Fs_mohamadi55@yahoo.com 10031947532846006719 10031947532846006719 No Inflammation and Inflammatory Diseases Division, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Nastaran Tarban nastarantarban88@gmail.com 10031947532846006720 10031947532846006720 No Department of Biology, Kish International Campus, University of Tehran, Kish, Iran Navid Momenifar na.momenifar@gmail.com 10031947532846006721 10031947532846006721 No Faculty of Basic Sciences and Advanced Technologies in Biology, Department of Cell and Molecular Biology Science, University of Science and Culture, ACECR, Tehran, Iran Mehdi Norouzi mnorouzi@tums.ac.ir 10031947532846006722 10031947532846006722 Yes Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran