Gingival concentrations of interleukin-23 and -17 at healthy sites and at sites of clinical attachment loss.

BACKGROUND

The presence of interleukin (IL)-23 has not been reported within inflamed gingiva, so we evaluated its concentration within gingiva from normal sites and sites of chronic periodontal disease.

METHODS

Gingiva was obtained prior to extraction of teeth. It was grouped based on clinical attachment loss (CAL): 0 to 2 mm (normal-slight), 3 to 4 mm (moderate), and >5 mm (severe). Tissues were solubilized, and IL-12, -23, -6, -17, and -1beta; interferon-gamma (IFN-gamma); and tumor necrosis factor-alpha (TNF-alpha) concentrations were assessed by enzyme-linked immunosorbent assay. Data were compared by factorial analysis of variance, post hoc Tukey test, and Pearson correlation test. Groups were defined as significantly different when P <0.05.

RESULTS

The gingival concentrations of IL-23, -17, -1beta, and -6 and IFN-gamma were significantly greater at moderate CAL sites than at normal-slight CAL sites. Gingival concentrations of IL-23, -1beta, -17, and -6 and TNF-alpha were significantly greater at severe CAL sites than at normal-slight CAL sites. In addition, the gingival concentrations of IL-23, -17, and -6 and TNF-alpha were significantly greater and the gingival concentrations of IL-12 and IFN-gamma were significantly lower at severe CAL sites than at moderate CAL sites. Gingival concentrations of IL-23, -17, -6, and -1beta and TNF-alpha correlated positively with CAL. The IL-23 gingival concentration correlated significantly with IL-17, -1beta, and -6 and TNF-alpha concentrations and correlated negatively with IL-12 and IFN-gamma concentrations.

CONCLUSIONS

Our results suggested the possibility that the IL-23/IL-17 immune response was present within chronically inflamed gingiva. This is a host response that had not been reported previously in periodontal disease and may be an important factor in the chronic nature of the disease.