Changes of Nasal Epithelial Cells and Mucus Layer after Challenge of Allergen

Abstract

It has been reported that the normal epithelium of the anterior nares is covered by a mucopolysaccharide layer with a depth of approximately 0.8μ¹. In the present study, a patient with an allergy to the Japanese cedar was found to develop a very thin mucopolysaccharide layer (0.05μ in depth) when the mucosal tissue was taken off before provocation. Adhering pollen particles could have readily come in contact with the plasma membranes of the epithelial cells. The epithelium of the nonciliated cells exfoliated in a relatively short period of time after provocation. Ten minutes after provocation, a thick mucus layer covered the exfoliated epithelial mucosa. Pollen particles could no longer be brought into contact with mucosa due to the mucus layer. On the other hand, no difference from the normal condition was seen before provocation in the middle and posterior nares where ciliated cells were located. However, at ten minutes after provocation, a large number of goblet cells appeared in place of ciliated cells, and mucus production was very much activated. Many signs appeared at this stage which suggested the impairment of ciliary beating. Specifically, there was swelling and damage of plasma membranes of cilia, bending of cilia, existence of extra cytoplasm around the microtubules in the cilia, and intrusion of mucus fluid between cilia. In the regions where ciliated cells were replaced by goblet cells, the exfoliation of epithelium could be noted, but it is generally difficult to find that ciliated cells are exfoliated even when the ciliary beating is impaired. Taking into account the above-mentioned results, it can be assumed that pollen particles penetrate the submucosa not only through the posterior nares where ciliary beating is impaired, but also through the anterior nares where epithelial cells are exfoliated.