The Contribution of Interleukin‐13 and ‐15 to the Cytokine Network Within Normal and Diseased Gingiva

Abstract

There are no comparisons of concentrations of interleukin (IL)-13 and -15 and gingival sulcular depth within healthy or inflamed gingiva. Study of non-oral inflammations indicated that IL-15 has similar functions to IL-2, and IL-13 has similar functions to IL-4 and -10. Thus, IL-13 and -15 likely have a function in gingival inflammation. We compared the concentrations of IL-13 and -15 within healthy or inflamed human gingiva to gingival sulcular depth and the concentration of various T-helper 1 and T-helper 2 cytokines in a group of Hispanic subjects. Gingival papillae were grouped by the depth of the adjacent gingival sulcus: <or=3 mm (normal); 3 to 6 mm and >6 mm (diseased). The gingival concentrations of IL-2, -4, -6, -10, -13, and -15 and interferon (IFN)-gamma were assessed by enzyme-linked immunosorbent assay. IL-2, -4, -6, -10, and -13 and IFN-gamma concentrations were higher within gingiva adjacent to 3 to 6 mm diseased compared to normal; IL-15 concentrations were significantly greater within normal gingiva than within diseased gingiva (P <0.001). Within gingiva adjacent to >6 mm sulci, IL-6 concentrations were significantly higher than in normal gingiva, and the concentrations of the other cytokines were similar to those in normal gingiva. Gingival IL-6 concentration correlated significantly with the adjacent gingival sulcular depth, whereas the IL-15 concentration correlated inversely with the adjacent gingival sulcular depth (P <0.001). IL-13, -4, and -10 had a similar concentration pattern within normal and diseased tissue; however, the concentration pattern of IL-15 was not similar to IL-2. Relatively low IL-15 concentrations within diseased gingiva suggest that IL-15 might have anti-inflammatory properties.