THE FINE STRUCTURE OF HUMAN TONSILLAR CRYPT EPITHELIUM

The fine structure of crypt epithelium in human palatine tonsils was studied by scanning electron microscopy (SEM).The tonsils were obtained from patients with chronic tonsillar infection. Immediately following tonsillectomy, the tonsils were puncture-perfused with glutaraldehyde fixatives. By this procedure, blood and tissue fluid were eliminated from the tissues. Specimens were freezecracked and the inside structure of the epithelium was exposed for examination by SEM.Crypt epithelium was classified into three types according to the three-dimensional structure. Type I epithelium: It was stratified squamous epithelium. In the basal and intermediate layers, intercellular space of the epithelial cells formed a network of canalicules, which were considered as passages for infiltrating cells.Type II epithelium: Epithelial cells were polygonal in appearance and possessed several cytoplasmic processes, by which they were connected with each other to form a meshwork in this epithelium. A large number of infiltrating cells were observed in the meshes of the epithelial cells, showing the state of "lympho-epithelial symbiosis". There were "cryptal micropores" in the surface layer, and they communicated the cryptal lumen to the network structure of the epithelium. It was suggested that the cryptal micropores might represent passages for infiltrating cells and various antigens.Type III epithelium: This epithelium showed a destruction of the superficial layer and marked cell infiltration. There were a lot of collagen fibers, several blood vessels and a few squamous epithelial cells in the epithelium. It was suggested that the construction of this epithelium was caused by chronic inflammation.Based on these results, it revealed that the type II epithelium was playing an important role in the immunological activity of the tonsil.