Concentrations of chemical mediators in nasal secretions of patients with hay fever during natural allergen exposure.

By using the microsuction technique, quantitative determination of the chemical mediators in nasal secretions was performed in 40 patients with seasonal allergic rhinitis during the pollen season. The aim of this study was to investigate the actual concentrations of these important mediators in nasal secretions during natural allergen exposure so as to better understand the pathophysiology of allergic rhinitis. The median concentrations of four mediators, were histamine: 51.5 ng/g (range: 4-146 ng/g); tryptase: 0 (range: 0-84 microU/g); leukotriene C4 (LTC4): 23 ng/g (range: 11-77 ng/g); and eosinophil cationic protein (ECP): 410 ng/g (range: 6-2380 ng/g). The authors compared these concentrations with those of the same mediator found in a previous study of seasonal allergic rhinitis patients after nasal challenge outside the pollen season. The present study demonstrates that during the season allergic rhinitis reflects a chronic state of allergic inflammation of the nasal mucosa involving various inflammatory mediators induced by one or more episodes of early type allergic reaction.