Nasal mucosal immunoexpression of the mast cell chemoattractants TGF-β, eotaxin, and stem cell factor and their receptors in allergic rhinitis

Background: Allergic rhinitis is characterized by the epithelial accumulation of cells, particularly mast cells and eosinophils. There is little information relating to the chemotaxins responsible for mast cell epithelial accumulation in this disease. Objective: Expression of the mast cell chemoattractants TGF-beta, eotaxin, and stem cell factor and their receptors was investigated in tissue sections from biopsy specimens obtained from patients with naturally occurring allergic rhinitis. Methods: Specific immunohistochemical staining was performed on thin sections of inferior turbinate biopsy specimens from patients with perennial and seasonal allergic rhinitis and, for comparison, from nonatopic and, where relevant, atopic healthy volunteers without rhinitis. Sequential staining of adjacent 2-mum sections was undertaken to colocalize TGF-beta receptors to mast cells. Results: Evidence was found of significantly increased epithelial immunoreactivity for TGF-beta1, TGF-beta2, TGF-beta3, TGF-beta receptor I, TGF-beta receptor II, and TGF-beta receptor III in patients with perennial and seasonal allergic rhinitis compared with that seen in healthy control subjects. TGF-beta receptors I and II were found to colocalize to mast cells. Eotaxin epithelial immunoreactivity was significantly increased in the perennial group, although there were no corresponding disease-related differences found in relation to CCR-3 immunoreactivity at this site. There was no increase in stem cell factor immunoreactivity within the epithelium in naturally occurring disease. Significant correlations were found between epithelial immunoreactivity for TGF-beta1, TGF-beta2, TGF-beta receptor I, TGF-beta receptor II, and the number of epithelial mast cells. Conclusion: These findings of enhanced epithelial TGF-beta immunoreactivity in patients with rhinitis, the correlation with intraepithelial mast cell numbers, and the colocalization of TGF-beta receptors to mast cells suggest that the epithelial expression of TGF-beta might represent an important biologic process involved in either the recruitment or retention of mast cells within the epithelium in naturally occurring allergic rhinitis.