Analysis of salivary levels of IL-1β, IL17A, OPG and RANK-L in periodontitis using the 2017 Classification of Periodontal Diseases - an exploratory observational study

Abstract

Periodontitis is a chronic disease with a high overall prevalence. It involves a complex interplay between the immune-inflammatory pathways and biofilm changes, leading to periodontal attachment loss. The aims of this study were (i) to assess whether the salivary IL-1β, IL-17A, RANK-L and OPG levels have the potential to discriminate between the mild and severe periodontitis conditions; and (ii) to enable diagnostic/prognostic actions to differentiate between distinct levels of the disease. The analysis of the clinical parameters and the evaluation of the salivary immunomediators levels by means of a multiplex flow assay revealed a statistically significantly higher level of IL-1β in the periodontitis III/IV patients, as well as a higher level of RANK-L in the periodontitis III/IV and I/II patients, when compared to the healthy controls. Furthermore, the grade C periodontitis patients presented a significantly higher level of RANK-L compared to the grade B and grade A patients. In the grade C patients, IL-1β had a positive correlation with the PPD and CAL indices and RANK_L had a positive correlation with CAL. The evidence emerging from this study associates the salivary IL-1β and RANK-L levels with an advanced stage of periodontitis, stage III/IV, and with grade C, suggesting the possible cooperative action of both in the inflammatory and bone loss events. In addition to IL-1β, RANK-L could be considered a combined diagnostic biomarker for periodontitis.