Level of Interleukin-35 in Gingival Crevicular Fluid, Saliva, and Plasma in Periodontal Disease and Health

Background: A novel member of the interleukin (IL)-12 family, IL-35 is an important inhibitory cytokine released by regulatory T cells. The aim of this study is to evaluate gingival crevicular fluid (GCF), saliva, and plasma levels of IL-35 in periodontal disease and health. Methods: Samples of GCF, whole saliva, and plasma were obtained from systemically healthy, non-smoking individuals with gingivitis (n = 20) or chronic periodontitis (CP) (n = 20) and periodontally healthy individuals (n = 20). Full-mouth clinical periodontal measurements, including probing depth (PD), bleeding on probing, gingival index, and plaque index (PI), were also recorded. Enzyme-linked immunosorbent assay was used to determine IL-35 levels in the samples. Data were tested statistically by analysis of variance and Pearson rank correlation test. . Results: All clinical parameters were significantly higher in the CP group than the healthy and gingivitis groups (P <0.001). The GCF total amount of IL-35 was significantly higher in the CP group than the other groups (P = 0.04), whereas the GCF concentration of IL-35 was significantly higher in the healthy group than the other groups (P = 0.002). There were significant differences among the study groups in terms of salivary IL-35 level (P <0.001), with the highest level observed in the healthy group and the lowest in the CP group. There was no statistical difference between groups in plasma levels of IL-35 (P >0.05). There was a positive correlation between GCF total amount of IL-35 and PD (r = 0.338, P = 0.03) and PI (r = 0.374, P = 0.005) parameters. Conclusions: IL-35 could have an important role in suppressing periodontal inflammation and maintaining periodontal health. Additional studies are required to evaluate its role in periodontal diseases.