Cytokine profiles of healthy and diseased sites in individuals with periodontitis

Objective: The aims of this study were: 1) to compare the levels of cytokines between healthy and diseased sites, in patients with untreated periodontitis; 2) to correlate cytokine levels with each other and with key periodontal pathogens, in healthy and diseased sites. Methods: Paired gingival crevicular fluid (GCF) samples were obtained from two healthy (probing depth (PD) and clinical attachment level (CAL) <= 3 mm without bleeding) and two diseased sites (PD and CAL >= 5 mm with bleeding on probing [BoP]) of patients with generalized stage III/IV grade B/C periodontitis. GCF levels of eighteen cytokines and subgingival levels of seven periodontal pathogens were assessed by multiplex immunoassay and qPCR, respectively. Results: A total of 112 subjects and 448 GCF samples were analyzed. The GCF levels of GM-CSF, IL-17, IL-1 beta, IL-2, IL-21, IL-23 and TGF-beta were significantly higher in the diseased than in the healthy sites (p < 0.05). Levels of IL-8 and MIP-1 alpha were significantly higher in the healthy than in the diseased sites (p < 0.05). In the healthy sites, IL-8 and MIP-1 alpha formed an independent cluster of cytokines and, MIP-1 alpha positively correlated with Porphyromonas gingivalis (p < 0.05). In deep sites, smoking negatively associated with GM-CSF, IL-10, IL-17, IL-23, IL-5, IL-6, IL7, IL-8 and MIP-1 alpha levels (p < 0.05). Conclusions: Diseased sites exhibited increased levels of T helper 17-related cytokines and TGF-beta while healthy sites presented increased levels of the chemokines, IL-8 and MIP-1 alpha. Patients with periodontitis may not only have inflammation in diseased deep sites, but also present significant hidden subclinical inflammation in their shallow clinically healthy sites.