en تخصصي Special مقالات اصلی Original Article <p style="text-align: justify;"><strong><em>Background:</em></strong> The prevalence of hepatitis C virus (HCV) infection is increasing worldwide. Cytotoxic T-lymphocyte-associated protein 4 (<em>CTLA-4</em>) may play a role in the intensity of the disease. The aim of this study was to evaluate the association between genetic variants of the <em>CTLA-4 </em>and HCV infection.</p> <p style="text-align: justify;"><strong><em>Methods:</em></strong> Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) was performed as the genotyping assay at four different positions (+49 A>G, -318 C>T, -1722 T>C, and -1661 A>G). Haplotypes were analyzed using PHASE software. Sixty-five HCV patients and 65 healthy individuals as controls who were referred to the hepatitis clinic in Mashhad, Iran, were recruited. Genomic DNA was extracted from whole blood of participants.</p> <p style="text-align: justify;"><strong><em>Results:</em></strong> In a dominant analysis model of the -1661 position (GG vs. AA+AG), the AA genotype was more common in controls than in patients (adjusted P = 0.0003; OR = 0.15, 95% CI = 0.051 -0.42). The GCAT haplotype was also more prevalent in controls than in patients (adjusted P = 0.01; OR = 0.40, 95% CI = 0.20-0.81). Furthermore, the ACGT/ACGT diplotype was more common in controls than in patients (P = 0.0037; OR = 0.15, 95% CI = 0.04-0.54). In addition, the ACGT/ACAT diplotype was more frequent in patients than controls (adjusted P =0.003; OR = 2.48, 95% CI = 1.37- 4.50).</p> <p style="text-align: justify;"><strong><em>Conclusions:</em></strong> Our results indicated that polymorphisms in <em>CTLA-4</em> and certain haplotypes may affect the risk of HCV infection in our population, although a larger sample size may be required to confirm this association.</p> CTLA-4 gene Polymorphism, Haplotype analysis, Hepatitis C virus 51 58 http://rbmb.net/browse.php?a_code=A-10-1-82&slc_lang=en&sid=1 Samaneh Sepahi 10031947532846005553 10031947532846005553 No Targeted Drug Delivery Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. Alireza Pasdar 10031947532846005554 10031947532846005554 No Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran - Division of Applied Medicine, Medical School, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK. Sina Gerayli 10031947532846005555 10031947532846005555 No Department of Biology, University of Western Ontario, London, Ontario N6A 5B7, Canada. Sina Rostami 10031947532846005556 10031947532846005556 No The Influenza Centre, Department of Clinical Science, University of Bergen, N-5021Bergen, Norway Aida Gholoobi 10031947532846005557 10031947532846005557 No Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Zahra Meshkat meshkatz@mums.ac.ir 10031947532846005558 10031947532846005558 Yes Antimicrobial Resistance Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.