Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 10 1 2013 01 30 23 31 Parichehr Behfarnia Assistant Professor, Periodontics Department, Dental School, Isfahan University of Medical Sciences, Isfahan, Iran. Reza Birang Seyed Sajad Pishva Mazdak Ghanjalikhani Hakemi Mitra Mohammadi Khorasani 2015 10 16 The T helper 17 (Th17) cells have been suggested to have osteoclast activating effects while T helper 2 (Th2) cells are considered to have an osteoprotective role in periodontitis. This study was to compare the markers of Th17 cells (RORC2 and IL-17 genes) with that of Th2 cells (IL-4 and GATA-3 genes) between healthy and periodontitis tissues.The samples were obtained from patients with periodontitis and healthy tissues. The mRNA expression levels of IL-17, RORC2, IL-4 and GATA-3 were measured in both groups using quantitative RT-PCR. The results were compared using SPSS 11.0. Correlation coefficient was analyzed by Spearman's rho test. Mann-Whitney was used to measure the difference between IL-17 and IL-4 as well as RORC2 and GATA-3.In periodontal lesions, the expression levels of all markers were significantly higher than the healthy tissue (p≤ 0.001). The results showed a significant increase in the number of markers of Th17 (RORC2 and IL-17 genes) compared to markers of Th2 (GATA-3, IL-4) in patients with periodontitis compared to controls (p≤0.002). A positive correlation between IL-17 and RORC2 (p≤0.05) and between IL-4 and GATA-3 (p≤0.001) was found.The results show that expression levels of IL-4, GATA-3, IL-17 and RORC2 increase significantly in periodontal lesions compared with the controls. In periodontal lesions, IL-17 levels are significantly greater than IL-4, which plays a protective role against alveolar bone loss. https://fid.tums.ac.ir/index.php/fid/article/view/711 https://fid.tums.ac.ir/index.php/fid/article/download/711/686