PEAK FLOW VARIABILITY AND SPUTUM EOSINOPHILIA IN ALLERGIC RHINITIS

Background: Although some non-asthmatic subjects with allergic rhiniti s exhibit airway hyperresponsiveness and increased diurnal peak expira tory flow (PEF) variation, little is known about the critical features that determine these physiologic alterations. Objective: In subjects with allergic rhinitis and methacholine hyperresponsiveness but no ast hma symptoms, we examined whether there were features of asthmatic air way inflammation. Methods: Forty non-asthmatic adults (11 with allergi c rhinitis and methacholine hyperresponsiveness, 20 with allergic rhin itis and normal methacholine responsiveness, and 9 healthy control sub jects) were studied. Sputum was induced with inhaled hypertonic saline for 5-minute periods for up to 20 minutes. Plugs from the lower respi ratory tract were selected for differential counting in cytocentrifuge d preparations. For the next 14 days, subjects measured their PEF two times daily. Peak expiratory flow variation was expressed as amplitude % mean. Results: Peak expiratory flow variation was significantly hig her in subjects with allergic rhinitis and methacholine hyperresponsiv eness than in allergic rhinitis patients with normal methacholine resp onsiveness and healthy controls. Eosinophil counts in the induced sput um were significantly higher in the subjects with allergic rhinitis an d methacholine hyperresponsiveness [median (interquartile range), 7.3 (9.0)%] compared with allergic rhinitis patients with normal methachol ine responsiveness [2.5 (3.8)%, P = .03] and healthy controls [1.0 (1. 0)%, P = .02]. Conclusion: We conclude that eosinophilic inflammation may be present in subjects with allergic rhinitis and airway hyperresp onsiveness even when there are no symptoms of asthma. This could indic ate that bronchial eosinophilia is insufficient to cause asthmatic sym ptoms.