Interleukin-11 and IL-17 and the pathogenesis of periodontal disease

Background: Interleukin (IL) -11 and IL-17 are cytokines that modulate the inflammatory process and have not been assessed within normal or inflamed gingival tissues. Our purpose was to compare concentrations of human IL-11 and IL-17 within healthy and diseased human gingiva to determine their possible role in the initiation or progression of periodontal diseases. Methods: Biopsies from healthy (non-hemorrhagic gingiva adjacent to a 3 mm gingival sulcus) and diseased gingiva (hemorrhagic gingiva adjacent to a 3 mm periodontal pocket) were studied. IL-11, IL-17, RANTES, and IL-6 concentrations were assessed within solubilized gingival biopsies by enzyme-linked immunosorbent assay. Data were compared by factorial analysis of variance and a post-hoc Tukey honestly significant difference (HSD) test. Regression analysis and partial correlation analysis (adjusted for sample weight) were also used to determine correlations between the variables. Results: Interleukin-11 concentrations were highest within gingiva adjacent to 3 mm diseased pockets (P <0.001), and IL-17 concentrations were highest at 4 to 5 mm sites compared to other sites (P <0.001). Gingival concentrations of both cytokines were significantly lower in gingiva adjacent to a greater than or equal to6 mm pocket. RANTES concentrations were significantly greater in gingiva adjacent to greater than or equal to6 mm pockets than in tissues derived from other sites (P <0.001). IL-11, IL-6, and RANTES concentrations were significantly correlated with sulcular depth. Conclusions: Gingival concentrations of IL-11 and IL-17 are different in diseased gingiva adjacent to 3, 4 to 5, and greater than or equal to6 mm pockets, suggesting that their concentrations change as a consequence of the progression of gingivitis to periodontitis and that both cytokines could have a significant role in this progression. These data may be useful for the design of procedures for prevention of periodontal disease.