Increase in epithelial mast cell numbers in the nasal mucosa of patients with perennial allergic rhinitis.

The aim of the study was to compare the numbers and distribution of mast cells in the nasal mucosa of perennial allergic rhinitis (PAR) patients and controls, as demonstrated by different staining methods for light microscopy. Biopsies of inferior turbinate mucosa were taken from 10 patients with PAR and 10 patients undergoing septoplasty or septorhinoplasty (control group). Sections for light microscopy were stained with azure A. chloroacetate esterase and an ABC immunohistochemical technique using antibody to tryptase. Three times more mast cells were found in the epithelium of PAR patients compared to controls using the immunohistochemical technique (p = 0.0074). This method demonstrated considerably more mast cells than the other stains. The increase in epithelial mast cells is consistent with the migration of mast cells seen in seasonal allergic rhinitis, and this may be important in the phenomenon of nasal priming seen after repeated antigen exposure.