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Functional morphology of tonsillar crypts in recurrent tonsillitis
Abstract:
The cryptal epithelia contained three types of micropores (termed microcrypt) in association with free cells. Type III microcrypts appeared between ordinary epithelial cells with microridges and "specialized epithelial cells". The specialized epithelial cells consist of ciliated cells and non-ciliated cells having secretory granules and pinocytotic vesicles. Horseradish peroxidase (HRP) was taken up by phagocytes which protruded from the microcrypt and the superficial squamous epithelial cells with pinocytotic vesicles of idiopathic hypertrophic tonsils. It is suggested that Type III microcrypts have two contradictory functions. One is an active absorption of exogenous antigens; and the other is an exclusion of exogenous invasions according to mucociliary function. In recurrent tonsillitis, HRP was remarkably detected in the dilated stratified squamous epithelial clefts, epithelial tunnels, subepithelial layers and in the lumen of the high endothelial venules. The occurrence of sclerotic germinal centres in recurrent tonsillitis, and in focal infection, was greater than in idiopathic tonsillar hypertrophy, whereas the incidence in appearance of specialized epithelial cells was less frequent in acute tonsillitis than in recurrent tonsillitis, and in focal infection.
Insights
Type III microcrypts in tonsils exhibit dual functions: antigen absorption and pathogen exclusion via mucociliary action. Recurrent tonsillitis shows increased antigen presence in epithelial tissues.
Area of Science:
- Immunology
- Cell Biology
- Otorhinolaryngology
Background:
- The tonsillar cryptal epithelium contains specialized cells and micropores (microcrypts).
- Type III microcrypts are found between ordinary and specialized epithelial cells, including ciliated and non-ciliated secretory cells.
Purpose of the Study:
- To investigate the function of Type III microcrypts in antigen uptake and immune response.
- To compare epithelial cell characteristics and antigen presence in idiopathic tonsillar hypertrophy versus recurrent tonsillitis.
Main Methods:
- Histological examination of tonsillar tissues.
- Horseradish peroxidase (HRP) uptake studies to trace antigen transport.
- Comparative analysis of epithelial cell types and germinal center morphology.
Main Results:
- Type III microcrypts actively absorb exogenous antigens via phagocytes and specialized epithelial cells.
- Mucociliary function may contribute to excluding exogenous invasions.
- Recurrent tonsillitis shows significant HRP presence in epithelial clefts, tunnels, and subepithelial layers, with fewer specialized epithelial cells compared to idiopathic hypertrophy.
Conclusions:
- Type III microcrypts possess contradictory functions of antigen absorption and invasion exclusion.
- The epithelial barrier in recurrent tonsillitis is compromised, facilitating antigen entry.
- Differences in specialized epithelial cells and germinal center morphology correlate with tonsillar disease states.