Research Article Association between IFN- +874A/T and IFN-R1 (-611A/G, +189T/G, and +95C/T) Gene Polymorphisms and Chronic Periodontitis in a Sample of Iranian Population Zahra Heidari, 1,2 Hamidreza Mahmoudzadeh-Sagheb, 1,2 Mohammad Hashemi, 3,4 Somayeh Ansarimoghaddam, 5 Bita Moudi, 1,2 and Nadia Sheibak 2 1 Infectious Diseases and Tropical Medicine Research Center, Zahedan University of Medical Sciences, Zahedan 98167-43175, Iran 2 Department of Histology, School of Medicine, Zahedan University of Medical Sciences, Zahedan 98167-43175, Iran 3 Cellular and Molecular Research Center, Zahedan University of Medical Sciences, Zahedan 98167-43175, Iran 4 Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences and Health Services, Zahedan 98167-43175, Iran 5 Department of Periodontology, School of Dentistry, Zahedan University of Medical Sciences, Zahedan 98167-43175, Iran Correspondence should be addressed to Hamidreza Mahmoudzadeh-Sagheb; histology@ymail.com Received 26 September 2015; Revised 6 December 2015; Accepted 8 December 2015 Academic Editor: Tommaso Lombardi Copyright © 2015 Zahra Heidari et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Interferon gamma (IFN-) is an immune regulatory cytokine that acts through its receptor and plays important role in progression of infammatory disease such as chronic periodontitis (CP). Te purpose of this study was to determine the diferences in the distribution of IFN- (+874A/T) and IFN-R1 (-611A/G, +189T/G, and +95C/T) gene polymorphisms among CP and healthy individuals and to investigate relationships between these polymorphisms and susceptibility to CP. Materials and Methods. 310 individuals were enrolled in the study including 210 CP patients and 100 healthy controls. Single nucleotide polymorphisms at IFN-  (+874A/T) and IFN-R1 (-611A/G, +189T/G, and +95C/T) were analyzed by ARMS-PCR and PCR-RFLP methods. Results. Te signifcant diference was found in genotype and allele frequency of IFN- (+874A/T) gene polymorphism in chronic periodontitis patients and healthy controls. Te distribution of genotypes and allele frequencies for IFN-R1 (-611A/G, +189T/G, and +95C/T) were similar among the groups and no diferences in the frequencies of alleles or genotypes of IFN-R1 genetic polymorphisms variants between case and control groups were detected. Conclusion. Te fnding of this study showed that IFN- +874A/T gene polymorphism may afect susceptibility to CP, whereas IFN-R1 genetic polymorphisms at -611A/G, +189T/G, and +95C/T were not associated with this disease. 1. Introduction Chronic periodontitis (CP) is a multifactorial infammatory disease that is initiated by the accumulation of dental plaque and destroys the dental attachment apparatus. Te interaction of this bacterial bioflm with the host immune system induces infammation and immune responses, which lead to progressive attachment loss, bone loss, and eventually tooth loss. Tis common complex infectious disease afects 10–15 percent of the adult population [1–4]. Te host infammatory immune reaction, genetic factors, and environmental factors afect the risk of developing periodontitis. Recent studies have demonstrated that elevated levels of infammatory biomarkers and genetic variants of some cytokines could cause susceptibility to periodontitis [4– 7]. Increase of cytokines such as interferons (IFNs) has been found in infected human periodontium and their levels can be associated with progression of lesions and severity of infammatory diseases. Interferons are a large family of Hindawi Publishing Corporation International Journal of Dentistry Volume 2015, Article ID 375359, 8 pages http://dx.doi.org/10.1155/2015/375359