Lymphocyte subsets of the nasal mucosa in perennial allergic rhinitis.

T cells have been considered to play a primary role in IgE-mediated atopic diseases, yet little is known about the T-cell subsets in the nasal mucosa of patients with perennial allergic rhinitis. To elucidate the characteristics of T cells at the site of allergic inflammation, we analyzed the proportions, phenotypes, stages of differentiation, and distribution of T-cell subsets in the nasal mucosa of 15 patients with house-dust-mite perennial allergic rhinitis (PAR) and 14 patients with chronic infective rhinitis (CIR), using flow cytometry and immunohistochemistry. We also examined the T-cell subsets in the peripheral blood (PBL) in conjunction with those of the nasal mucosa in 10 patients with PAR and in nine patients with CIR. Our results revealed no obvious difference in the percentage of nasal CD3+ T cells, CD8+ T cells, and alpha beta T cells in the PAR and CIR patients. In contrast, CD4+ T cells (p < 0.05), CD3+4-8- double-negative T cells, (p < 0.01), and gamma delta T cells (p < 0.01) were significantly increased in the nasal mucosa of PAR patients. A majority of the CD4+ T cells in the nasal mucosa of PAR patients coexpressed the CD45RO surface molecule, and a predominant proportion of CD4+ T cells in the nasal coexpressed the CD45RO surface molecule, and a predominant proportion of CD4+ T cells in the nasal epithelium were CD45RO+. The ratio of CD4+ CD45RO+:CD4+ CD45RA+ T cells in the allergic patients' nasal mucosa was significantly greater than that in autologous peripheral blood (p < 0.01). The proportion and stages of activation and differentiation of T-cell subsets in the allergic patients' nasal mucosa were independent of those in the peripheral blood. An increase in the proportion of natural killer (NK) cells was observed in the nasal mucosa of CIR patients. Taken together, our results suggest that nasal T cells exhibit distinct patterns of distribution, differentiation, and activation in different inflammatory conditions of the nose. PAR is characterized by a selective increase in CD4+ memory T cells, CD3+4-8- double-negative T cells, B cells, and gamma delta T cells in the nasal mucosa. The increase in CD4+ memory T cells in the allergic nasal epithelium may have critical implications in the pathogenesis of PAR.