BACKGROUND: The oral cavity significantly influences systemic health. Gingivitis, an early reversible stage of periodontal disease, may trigger systemic immune changes by facilitating bacterial translocation. This study examined the immune responses elicited by experimental gingivitis and their systemic immune impact, specifically in relation to the oral commensal Viridans group streptococci (VGS). METHODS: Thirteen healthy participants (aged 18-55 years) underwent an experimental gingivitis model. Participants ceased oral hygiene practices for 3 weeks to induce gingival inflammation, followed by a 3-week resolution period with resumed oral hygiene. Blood and oral samples were collected at 4 timepoints to measure epithelial barrier function markers, polymorphonuclear leukocytes (PMNs) counts, and activation marker expression, as well as total and anti-VGS immunoglobulin IgG and IgA levels in the serum, which were measured using flow cytometry and enzyme-linked immunosorbent assay. RESULTS: Gingivitis induction led to significant increases in clinical parameters, which were nearly, but not completely, restored after resuming oral hygiene. Serum sCD14 and LBP levels (markers of epithelial integrity) increased in the gingivitis phase, and sCD14 remained high after the recovery phase on day 42 (p < 0.05). Similarly, PMN counts and surface marker expression in the blood were significantly upregulated during inflammation. PMNs remained primed, displaying higher responses to stimulation on day 42. Total serum IgG and IgA levels increased (p < 0.05), with elevated Anti-VGS IgA levels that were borderline significant (p = 0.06). CONCLUSION: Experimental gingivitis triggers immune responses that remain elevated during the early phase of clinical improvement. Elevated levels of sCD14 and heightened PMN activity indicate ongoing subclinical inflammation and epithelial barrier dysfunction. PLAIN LANGUAGE SUMMARY: The mouth is connected to the rest of the body-and has broader implications for overall health-than many people realize. This study explored how gingivitis, a common and reversible form of gum disease, can trigger changes that extend beyond the mouth. Thirteen healthy adults temporarily stopped brushing and flossing for 3 weeks to develop gingivitis, then resumed their oral hygiene for another 3 weeks. During this period, we collected blood and saliva samples to monitor immune responses. We found that even after participants resumed oral hygiene and their gums appeared mostly healed, some immune markers remained elevated, suggesting that low-level inflammation persisted. Immune cells in the blood became more active, and levels of antibodies, especially those targeting common mouth bacteria, increased. These findings indicate that even mild gum disease can have lasting effects on the body's immune system and potentially influence overall health.
Elebyary et al. (Wed,) studied this question.