Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis

Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma w hich is often associated with airways inflammation. However, some patients with allergic rhinitis and no clinical evidence of asthma also exhibit BHR. This study therefore investigated whether inflammatory cell infiltrate is present in the induced sputum of nonasthmatic subjects with allergic rhinit is during the pollen season and examined its relationship with airway hyper responsiveness to inhaled methacholine and adenosine 5'-monophosphate (AMP) . Twenty subjects (12 allergic rhinitis, eight nonallergic controls) underwen t metha- choline and AMP challenge and sputum induction with hypertonic sal ine on separate days. Cell differentials were calculated from whole sputum samples. A significantly greater number of eosinophils was found in the sputum of no nasthmatic subjects with allergic rhinitis compared to that of nonallergic controls, their median (range) percentages being 17.5 (4-47) and 1.5 (0-5) (p<0.001) respectively. Although sputum eosinophilia failed to be significa ntly associated,vith methacholine responsiveness (rs= -0.50; p=0.095), the provocative concentration of AMP causing a 20% fall in forced expiratory vo lume in one second correlated strongly and significantly with the absolute number of eosinophils (rs=-0.73; p=0.007). Eosinophil cationic protein levels in the sputum of rhinitic subjects were significantly elevated compared to controls and correlated with eosinophil number (rs=0.67; p=0.017). These findings support the view that bronchial eosinophilia alone is insuff icient to cause asthmatic symptoms. Diverse agonists for assessing bronchia l hyperresponsiveness are selectively associated,vith airway inflammation i n allergic rhinitis.