Atopic biomarker changes after exposure to Porphyromonas gingivalis lipopolysaccharide: a small experimental study in Wistar rats [version 1; peer review: awaiting peer review]

Background: IgE and IgG₄ are implicated in atopic development and clinically utilized as major biomarkers. Atopic responses following certain pathogens, such as Porphyromonas gingivalis (Pg), are currently an area of interest for further research. The aim of this study is to measure the level of IgE, IgG₄, and IgG₄/IgE ratio periodically after exposure of periodontal pathogen Pg lipopolysaccharide (LPS). Methods: We used 16 Wistar rats (Rattus norvegicus) randomly subdivided into four groups: Group 1, injected with placebo; Group 2, injected with LPS Pg 0.3 μg/mL; Group 3, injected with LPS Pg 1 μg/mL; and Group 4, injected with LPS Pg 3 μg/mL. Sera from all groups were taken from retro-orbital plexus before and after exposure. Results: Levels of IgE and IgG₄ increased significantly following exposure of LPS Pg at day-4 and day-11. Greater increase of IgE rather than IgG4 contributed to rapid decline of IgG4/IgE ratio, detected in the peripheral blood at day-4 and day-11. Conclusion: Modulation of atopic responses following exposure to LPS Pg is reflected by a decrease in IgG₄/IgE ratio that accompanies an increase of IgE. Therefore, Pg, a keystone pathogen during periodontal disease, may have a tendency to disrupt atopic biomarkers.