[Nonspecific bronchial hyperreactivity in asthma patients with or without allergic rhinitis]

Bronchial hyperresponsiveness is the main pathophysiological feature of asthma. Eosinophilic inflammation of airway is one of main factors influencing bronchial hyperresponsiveness. The aim of the study was to evaluate bronchial responsiveness to methacholine and exercise of asthma patients with or without allergic rhinitis and to estimate relations between eosinophil count in nasal secretion and non-specific bronchial hyperresponsiveness. Ninety eight patients with mild or moderate asthma were examined. Seventy eight patients had mild allergic rhinitis. Patients were divided in two groups: asthma with rhinitis group (n=78) and asthma group (n=20). Bronchial responsiveness was tested with methacholine and exercise challenges. Allergic status was determined by skin prick tests, mean wheal size and eosinophil count in the blood and nasal secretion. Atopy was more frequent (p=0.001) and mean wheal size larger (p=0.002) in asthma with rhinitis group. No difference estimated on blood eosinophil count (p=0.125) between both groups. Nasal eosinophil count was higher in asthma with rhinitis group comparing with asthma group (p=0.001). Methacholine provocative dose (PD(20)) was lower and the slope of the dose-response curve higher in asthma with rhinitis group, but not statistically significantly: PD(20) 173.0+/-27.0 microg and 212.1+/-52.9 microg, accordingly, p=0.179; the slope of the dose-response curve - 23.6+/-1.6 and 20.7+/-2.5, p=0.219. Exercise-induce bronchoconstriction developed equally: to 46% patients (n=36) from asthma with rhinitis group and 45% patients (n=9) asthma group. No significant differences were found between maximal fall of FEV(1)after exercise (DeltaFEV (1)): 24.2+/-2.3% and 25.9+/-4.0%, accordingly, p=0,744; area under the curve (AUC(0-30)): 451.6 +/- 48.9 % x sec. and 484.0+/-111.0% x sec., p=0.777. No statistical significant correlations were evaluated between nasal eosinophilia and PD(20), the slope of the dose-response curve, DeltaFEV(1) and AUC(0-30).

No significant differences were estimated on bronchial responsiveness to methacholine and exercise between asthma patients with or without allergic rhinitis. Eosinophil count in nasal secretion did not correlate with non-specific bronchial hyperresponsiveness.