Lamina propria dendritic cells express activation markers and contact lymphocytes in chronic periodontitis

BACKGROUND: Dendritic cells are characterized by shape, structure, and membrane molecule expression; they contact T lymphocytes to present antigens and stimulate plasma cell differentiation in vitro. Dendritic cells are known to be present in healthy human gingiva and to be altered in HIV-associated periodontitis. Here, we address the phenotype, location, and intercellular relationships of dendritic cells in chronic periodontitis. METHODS: Biopsies from patients with chronic periodontitis were analyzed by electron microscopy and indirect immunofluorescence for dendritic cells and lymphocyte markers. RESULTS: Langerhans' cells were spread in oral epithelium but restricted to the basal layer in pocket epithelium; they did not usually express major histocompatibility complex (MHC)-II antigens nor contact lymphocytes. Dendritic cells were abundant in the lamina propria of pocket epithelium; they were MHC-II positive, admixed with CD4-positive and CD8-positive T lymphocytes, and, they expressed CD54, CD80, and CD86. Dendritic cells often contacted lymphocytes and were also located within plasma cell aggregates. CONCLUSIONS: The data suggest that prerequisites for mounting a T cell-mediated immune response exist in chronic periodontitis, although this response is limited to the lamina propria. These results suggest that T-cell responses offer limited protection and can contribute to tissue damage during periodontal disease.