Local and systemic antibody responses for maintaining gingival health

Periodontitis is a chronic inflammation of the gingival tissue leading to
destruction of tooth support in the bone. Most people (90%) are relatively
well-protected against the pathologic conversion from mild, reversible gingival
inflammation (gingivitis) into destructive periodontitis. However, 10% of the
people do develop periodontitis, for reasons unknown currently.

In the periodontitis lesion, a large leukocytic infiltrate can be found with
high frequencies of plasma cells. The plasma cells have as main goal the
production of antibodies (immunoglobulins). We hypothesize that in healthy
individuals, IgA responses control dental plaque and biofilm formation, whereas
in periodontitis abnormal IgG responses induce chronic inflammation and may
also be associated with auto-immunity. Therefore, we wish to study whether
local immunoglobulin responses contribute to chronic tissue destruction in
periodontitis. We will investigate the control of bacteria by local and
systemic antibody production and how this is disturbed in periodontitis.

In this project, we aim to study how local and systemic antibody by distinct B-
and T-cell populations control periodontal health, in particular control the
conversion of gingivitis into destructive periodontitis. Which types of B cell
responses are required to control bacteria in the gingival crevice? How are
these responses deregulated in patients with periodontitis?
By doing this, we hope to gain more insight in the mechanisms involved in the
development of periodontitis, which might be usefull for treating periodontitis
in the future.

In patients with diagnosed periodontitis or gingivitis and in healty controls,
we want to study different immune cells both in tissue (locally) and in blood
(systemically). With new flowcytometric and molecular techniques we want to
determine for example different B- and T-cell subsets in the different groups,
and clone antibodies from single sorted plasma cells and test their reactivity.
The study will be cross-sectional, observational with 1x collection of blood
and a microbial sample of the tooth plaque, and collection of gingival tissue
(that is removed during regular treatment).

When the patient agrees to enter the research, this will be planned with a
scheduled treatment. At this point, the patient will sign the informed written
consent, after which 2 samples of 9ml blood will be taken and a microbial
sample of the toothplaque. The total burden will thus be one venapuncture and a
microbial swab (non-invasive). There are no additional health risks,only a
small chance for a minor bruise due to the venapuncture, because there is no
intervention.