Evaluation of Interleukin-36 levels in saliva and gingival crevicular fluid of patients with periodontal disease

Aim: Interleukin-36 (IL-36), recently identified and members of the IL-1 family, have been reported to be important regulators of host defense against pathogens in the oral mucosa. The aim of this study was to investigate the levels of IL-36 alpha (α) in saliva and gingival crevicular fluid (GCF) of patients with periodontitis, gingivitis and periodontally healthy individuals and to compare these levels with clinical parameters. Materials and Methods: A total of 80 systemically healthy, non-smokers aged between 25 and 55 including 20 periodontally healthy individuals, 20 individuals with gingivitis, 20 individuals with Stage III Grade B periodontitis, and 20 individuals with Stage III Grade C periodontitis were involved in our study. Clinical parameters, including plaque index (PI), gingival index (GI), probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP), were recorded. GCF and unstimulated saliva samples were collected from all participants. IL-36α levels were quantified using enzyme-linked immunosorbent assay (ELISA). Results: According to the study results, all clinical parameters were found to be statistically significantly higher in the periodontitis groups compared to the periodontally healthy and gingivitis groups, and among the periodontitis groups, only the CAL value was found to be significantly higher in Grade C compared to Grade B (P<0.05). When IL-36α data were evaluated, salivary levels and total amounts of GCF were found to be significantly higher in the periodontitis groups compared to the periodontally healthy and gingivitis groups, and total amounts of GCF IL-36α were found to be higher in the gingivitis group compared to the periodontally healthy group (P<0.05). It was determined that there was no significant difference between the periodontitis groups in terms of GCF and salivary IL-36α levels (P>0.05). On the other hand, strong positive correlations were found between GCF IL-36α total amounts and salivary IL-36α levels and GI, PPD and CAL values (P<0.001). Conclusion: Our study demonstrates for the first time that IL-36α is involved in the periodontal disease process and that salivary and GCF levels increase in the presence of periodontal disease. The findings of our study suggest that IL-36α can be used as a potential biomarker in elucidating the developmental mechanisms of periodontal diseases.