Topical nasal corticosteroid therapy produces clinical improvement in patients with nasal polyposis. To examine the mechanisms of steroid effect, we quantified the number of inflammatory cell types as well as the expression of relevant cell markers in nasal polyps from steroid treated patients (n = 11) and polyps from untreated patients (n = 10) judged to require polypectomy for symptomatic relief. We found that the majority of eosinophils in these tissues were in the stromal layers, and that the proportion of activated eosinophils (EG2+ versus total eosinophil count) was significantly lower in polyps from patients treated with the topical nasal steroid budesonide, 200 to 400 micrograms/d for 1 mo, than in polyps from untreated patients. We also found that in polyps from treated patients, the superficial stromal layer (SSL) and deep stromal layer (DSL) both contained a significantly lower tissue density of lymphocytes of CD3, CD4, and CD8 subsets. Treatment was also associated with a lower, albeit nonsignificant, expression of ICAM-1 and HLA-DR in the epithelium. The tissue density of CD14+ cells (monocyte/macrophage) and of tryptase+ cells (mast cells) was the same in the two groups. These findings demonstrate tissue effects of topical corticosteroid treatment which may point to the mechanisms of therapeutic benefit. In addition, these observations illustrate the value of markers that indicate cell functional activity rather than just cell numbers.

The proliferative activity of mast cells in the nasal mucosae of allergic (n = 14) and non-allergic (n = 18) rhinopathic patients was studied by a sequential double immunohistochemistry using anti-proliferating cell nuclear antigen (PCNA) and anti-tryptase antibodies. Two hundred to 300 tryptase-positive cells (mast cells) were studied in each allergic nasal epithelium. In case of non-allergic nasal mucosa, only a few mast cells existed in the epithelial layer. The total number of mast cells which we could detect in all patients was 168 cells. One of these cells contained PCNA. Three hundred to 500 mast cells were studied in each subepithelial layer and deep layer of lamina propria of both diseases. PCNA-positive mast cells were observed in the nasal epithelia of 10 allergic patients. In the subepithelial layer, PCNA-positive mast cells were observed eight allergic patients and four non-allergic patients, respectively. In the deep lamina propria, PCNA-positive mast cells were observed in a few patients with both diseases. The percentage of PCNA-positive mast cells of all mast cells each area ranged from 0 to 1.7%. The incidence of PCNA-positive mast cells was statistically higher in the allergic epithelium and subepithelial layer than in the deep layer of lamina propria. Moreover, that of PCNA-positive mast cells in the subepithelial layer was higher in allergic than in non-allergic nasal mucosa. Our results suggest that mast cell proliferation may contribute to the number of mast cells in the nasal epithelium and subepithelial layer of allergic patients.

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