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The lymphoepithelial organization of the tonsil: an immunohistochemical study in chronic recurrent tonsillitis
L P Ruco1, S Uccini, A Stoppacciaro
1Department of Experimental Medicine, University La Sapienza, Rome, Italy.
Insights
Leukocyte infiltration in chronic tonsillitis involves diverse immune cells interacting with epithelial cells. This study reveals specific immune cell compositions and extracellular matrix interactions within tonsillar tissue.
Area of Science:
- Immunology
- Cell Biology
- Pathology
Background:
- Chronic recurrent tonsillitis involves complex immune responses within the tonsillar tissue.
- Understanding leukocyte-epithelial interactions is crucial for elucidating disease mechanisms.
Purpose of the Study:
- To investigate the cellular composition and interactions of leukocytes within the crypt epithelium in chronic recurrent tonsillitis.
- To analyze the expression of adhesion molecules and extracellular matrix components and their relationship with immune cell infiltration.
Main Methods:
- Immunohistochemistry and cytofluorimetric analysis were performed on 12 cases of chronic recurrent tonsillitis.
- Analysis included cell suspensions, Ki-67 staining for proliferation, and staining for adhesion molecules (ICAM-1, VCAM-1) and extracellular matrix (ECM) components.
Main Results:
- Intraepithelial leukocytes comprised B lymphocytes (CD20+), T lymphocytes (CD4/CD8 ratio 2.7), and macrophages (CD68+).
- Approximately 4% of intraepithelial leukocytes were proliferating (Ki-67+).
- Leukocyte infiltration correlated with ICAM-1 and VCAM-1 expression on epithelial cells and varied ECM distribution with differential integrin expression on lymphocytes.
Conclusions:
- Leukocyte infiltration in chronic tonsillitis is a dynamic process involving specific immune cell populations and epithelial adhesion molecules.
- The study highlights the intricate relationship between the extracellular matrix and immune cell behavior in the tonsillar microenvironment.
Abstract:
Interactions between leukocytes and crypt epithelium were extensively investigated in 12 cases of chronic recurrent tonsillitis, using immunohistochemistry and cytofluorimetric analysis of cell suspensions. Intraepithelial 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 indicated by Ki-67 staining. Leukocyte infiltration is associated with expression on epithelial cells of the adhesion molecules ICAM-1 and VCAM-1. Crypt epithelium is supported by a basement membrane showing frequent interruptions and connected with the reticular stroma of the lymphoid 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 area and that B and T lymphocytes exhibited different patterns of integrin expression.