Immunohistological analysis of gingival lymphocytes in adult periodontitis.

Inflammatory periodontal diseases are mediated by interactions between the dental plaque and the components of the host immune system. This study was designed to analyse the phenotypic properties of gingival lymphocytes in adult periodontitis. Biopsies were obtained from 12 patients and aged between 35 and 55 years. The tissues were processed for both histopathological and immunohistological examinations. Gingival tissue lymphocytes were identified using monoclonal and polyclonal antibodies with the immunoperoxidase technique. All specimens revealed a significant degree of CD3(+) cell infiltration beneath the pocket epithelium, which is located adjacent to the bacterial plaque, compared to that on the oral epithelial side. CD4(+) and CD8(+) cells were evenly distributed within these infiltrates. Numerous HLA-DR(+) cells were also noted. The majority of plasma cells in the central lamina propria bore IgG isotypes. These findings suggest that T-cell mediated regulatory mechanisms play an important role in the pathogenesis of adult periodontitis.