Analysis of Osteoimmune Interactions Linking Inflammation and Bone Destruction in Aggressive Periodontitis

Context: Periodontitis are inflammatory diseases affecting the periodontium and characterized by the destruction of the tooth-supporting bone due to increased bone resorption by osteoclasts (OCLs). Two forms are described: chronic periodontitis (CP) and aggressive periodontitis (AP) that differ by the severity and rapidity of bone loss, much more important for AP than CP. In both forms, the link with uncontrolled activation of the immune system is largely admitted. But despite the physiopathology of CP is fairly well studied, very few data are available regarding AP. Based on the investigators previous studies, their hypothesis to explain this severity is the existence of a vicious circle involving immune cells, mesenchymal cells and OCLs, that would maintain and amplify inflammation and bone loss.

Study: this is a transversal, interventional and single-center study. It includes 3 groups of 20 patients: affected with AP, CP or controls (necessitating an extraction of wisdom teeth).

Aims: the investigators will compare the proportion of immune and mesenchymal cells in the 3 groups of patients to identify the populations potentially involved in bone destruction. The investigators will compare in vitro their capacity to induce OCL differentiation in order to determine their role in bone loss. The investigators will also compare the capacity of OCLs and mesenchymal cells to activate T cells, in order to determine their role in inflammation.

Methodology: patients will be recruited in the department of periodontology, CHU of Nice. After signing the informed consent, a biopsy of periodontal granulation tissue (surgical waste) will be collected during the usual treatment of these diseases, as well as a blood sample. Then, patients will leave the study. Cells from the biopsies will be analyzed by flow cytometry to determine the proportion of lymphocytic, monocytic and mesenchymal cells. In vitro, their capacity to induce OCL differentiation or to activate T cells will be determined. From the blood samples, OCLs will be generated to study their capacity to activate T cells.

Chronology of consultations and examinations: 3 visits are planned: (1) a routine visit corresponding to the usual treatment of the patient during which it is proposed to participate in the study, (2) a visit to obtaining consent, clinical examination, criteria verification and (3) a visit corresponding to the usual treatment in which will be collected tissue biopsies and blood.