THE LYMPHOEPITHELIAL ORGANIZATION OF THE TONSIL - AN IMMUNOHISTOCHEMICAL STUDY IN CHRONIC RECURRENT TONSILLITIS

Interactions between leukocytes and crypt epithelium were extensively investigated in 12 cases of chronic recurrent tonsillitis, using immun ohistochemistry and cytofluorimetric analysis of cell suspensions. Int raepithelial leukocytes are a mixed cell population composed of 50 per cent CD20-positive B lymphocytes, 40 per cent T lymphocytes with a 2 . 7 CD4/CD8 ratio, and 10 per cent CD68-positive macrophages. About 4 per cent of intraepithelial leukocytes are proliferating cells, as ind icated by Ki-67 staining. Leukocyte infiltration is associated with ex pression on epithelial cells of the adhesion molecules ICAM-1 and VCAM -1. Crypt epithelium is supported by a basement membrane showing frequ ent interruptions and connected with the reticular stroma of the lymph oid tissue, which was stained for fibronectin, tenascin, collagen, and laminin. Extracellular matrix (ECM) distribution was correlated with integrin expression on B and T lymphocytes. It was found that the ECM was arranged differently in the follicles and in the extrafollicular a rea and that B and T lymphocytes exhibited different patterns of integ rin expression.