Comparison of the microanatomical distributions of macrophages and dendritic cells in normal and diseased tonsils.

The palatine tonsils play an important role in immunologic surveillance and resistance to infection in the upper aerodigestive tract. Dendritic cells and macrophages function to capture and process antigen and present it to T lymphocytes, a critical step in the early immune response. Few studies have characterized the distribution and phenotype of those antigen-presenting cells in the normal palatine tonsil, or determined how those parameters change with disease. Immunohistochemical analysis was performed to determine the microanatomical distribution, quantity, morphology, and phenotype of macrophages and dendritic cells in both normal and diseased tonsils. Differences were observed in macrophage and dendritic cell distribution, quantity, and phenotype in the surface and crypt epithelium. The number of macrophages was significantly increased in all compartments in all disease groups (p < .05), although the number of macrophages that expressed phenotypes of maturity and/or activation was not concomitantly increased. In the surface epithelium, Langerhans and interdigitating cells decreased significantly with disease (p < .05). Chronic infection may impose an immunosuppressive effect on responses within tonsil tissue, affecting the immunologic factors responsible for macrophage maturation and activation.