To clarify whether tissue remodelling of the nasal mucosa is caused by allergic inflammation or not, we studied the amount and distribution of collagen in human nasal mucosa of 13 perennial allergic patients and 13 non-allergic subjects. The total amount of collagen and other proteins in nasal mucosa was determined by absorbency at 540 nm and 605 nm of a solution eluted from tissue sections stained with sirius red and fast green. Distribution of collagen type I, III and IV was observed by immunohistochemistry. The thickness of the basement membrane zone underlying epithelia was histologically estimated. Results were as follows: i) There was no significant difference in the total amount of collagen between allergic and non-allergic subjects. ii) Although there was no obvious change in localization of the three types of collagen, extensive immunoreactivity for types I and III collagen was observed at subepithelial basement membrane zone in allergic subjects. iii) The thickness of the basement membrane zone, which corresponds to regions positive for types I and III collagen antibodies, was statistically significantly greater in allergic subjects than in non-allergic ones. We thus concluded that tissue remodelling occurs in the allergic nasal mucosa, and that it is especially obvious in the basement membrane zone.
Conclusion: These results suggest that mast cells (MCs) play a role in promoting nasal polyp (NP) formation and progression with a-smooth muscle actin (a-SMA)-positive cells. Objectives: We studied the quantification and the localization of MCs and myofibroblasts in NPs. Patients and methods: We examined NPs from 12 patients with chronic rhinosinusitis undergoing endoscopic sinus surgery. MCs and myofibroblasts that expressed a-SMA were detected immunohistochemically. The numbers of labeled cells were quantified in NPs. These cells were evaluated in the tip, central, and pedicle areas. The number of MCs was compared between low (zone 1), moderate (zone 2), and high (zone 3) zones of a-SMA-positive cells.Results: The number of MCs was significantly higher in pedicle areas than in tip areas of NPs. The distribution of a-SMApositive cells tended to be more remarkable in pedicle areas than in tip and central areas of NPs. The number of MCs was significantly higher in zone 3 than in zone 1 of a-SMA-positive cells.
The purposes of this study were to clarify whether damage of the nasal epithelium exists in patients with nasal allergy, and how the morphology of the epithelium changes after topical allergen challenge. Electron microscopy revealed 2 characteristic features in the nasal epithelium of patients with perennial nasal allergy--an increase in the number of epithelial cells with cytoplasmic vacuoles, and markedly widened intercellular spaces--although these changes were unclear under light microscopy. The density of vacuolated cells significantly increased 24 hours after allergen challenge. Further, the number of eosinophils that were associated with vacuolated cells was significantly higher in patients with nasal allergy than in controls. These morphological changes, thus, were considered to be types of damage to the nasal epithelium associated with nasal allergy. Such changes may be among the causes of nasal hyperreactivity, which is an important feature of nasal allergy.
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