Expression Levels of Th-2 and Th-17 Characteristic Genes in Healthy Tissue Versus Periodontitis

Objective: 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 osteopro-tective 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 periodonti-tis tissues. Materials and Methods: The samples were obtained from patients with perio-dontitis 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 re-sults 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. Results: In periodontal lesions, the expression levels of all markers were signifi-cantly 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 con-trols (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. Conclusion: 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.