Analysis of YKL-40 Acute-Phase Protein and Interleukin-6 Levels in Periodontal Disease

Background: YKL-40, a new acute-phase protein, is shown to be elevated in inflammatory diseases, such as rheumatoid arthritis, type 2 diabetes mellitus, and coronary artery diseases. However, there is no data indicating a relationship between YKL-40 and periodontal disease. Interleukin-6 (IL-6) is the major regulator of acute-phase protein synthesis and one of the most studied inflammatory markers in periodontal disease. The purpose of the present study is to evaluate YKL-40 and IL-6 levels in gingival crevicular fluid (GCF) and serum of patients with periodontal disease and healthy individuals. Methods: Periodontally healthy individuals (n = 15), patients with gingivitis (n = 15), and patients with severe chronic periodontitis (CP) (n = 15) without any systemic disease were included in the study. Clinical measurements were recorded; GCF and blood samples were obtained from each participant. GCF and serum YKL-40 and IL-6 levels were analyzed by enzyme-linked immunosorbent assay. Statistical analysis was performed by parametric and non-parametric tests. Results: Total amounts of YKL-40 and IL-6 in GCF as well as serum YKL-40 and IL-6 levels were significantly higher in patients with gingivitis and CP compared with healthy controls (P <0.01). YKL-40 levels in GCF and serum as well as serum IL-6 levels were significantly higher in patients with CP compared with patients with gingivitis (P <0.01). Conclusions: YKL-40 levels in GCF as well as serum YKL-40 and IL-6 levels increased from gingivitis to periodontitis. Within the limits of the present study, the YKL-40 molecule might be a potential novel inflammatory marker of periodontal disease.