Expression of Cytokine Receptors and HLA in Nasal Epithelial Cells

Epithelial cells can actively contribute to airway inflammation by virtue of their ability to participate in antigen presentation, and to synthesize and release proinflammatory cytokines. This study used immunocytochemistry to investigate interleukin 1 receptor (IL-1R) type I, tumor necrosis factor a receptor (TNF-aR) 55 kD and HLA-DR on epithelial cells obtained via nasal brushing from 10 patients with allergic rhinitis in season and 15 healthy non-allergic subjects. Firstly, we found that approximately 40% of healthy non-allergic subjects had some macroscopic evidence of inflammation in the nasal mucosa and that their epithelial brushings contained more than 10% neutrophils. These subjects were described as having subclinical inflammation. Secondly, in brushings from control subjects, we found that 8.0±7.5% of epithelial cells stained positive for HLA-DR, about one third stained positive for IL-1R and TNF-αR. The percentage of epithelial cells staining positive for these three markers was similar in patients with allergic rhinitis in season and with subclinical neutrophilic inflammation, and significantly increased compared to control subjects. Thirdly, in non-allergic subjects, a significant correlation was found between HLA-DR expression and both neutrophil and lymphocyte content in the epithelial brushings. These findings further support a contribution of epithelial cells to the regulation of inflammatory and immunological processes in the nasal mucosa.