Characterization of inflammatory cell infiltrate in dental periapical lesions.

Sixty-three dental periapical lesions were investigated in order to study the involvement of inflammatory and immunologic reactions in the pathogenesis and maintenance of chronic apical periodontitis. Of 61 well-preserved specimens, 38 were classified as granulomatous, 3 as exudative periapical granulomas and 20 as periapical scars. The quantitative composition of T-lymphocyte subpopulation and macrophages, the proportion of IgE-producing cells compared with other immunoglobulin producing plasma cells, and the tissue distribution of IgE-producing plasma cells compared with that of mast cells were determined in the granulomatous types of granulomas using immunofluorescent, immunohistochemical and enzymehistochemical methods. The results indicated a decreased ratio of helper/inducer versus cytotoxic/suppressor T-lymphocytes, a remarkably high proportion of macrophages, a low frequency of IgE-producing plasma cells with different localization when compared with that of mast cells. These observations suggest that T-lymphocytes and macrophages may play an important role in the complex events of tissue destruction and repair taking place in the periapical region.