Induced sputum eosinophils, bronchial reactivity, and cough sensitivity in subjects with allergic rhinitis

Some patients with allergic rhinitis and no clinical evidence of asthma exhibit bronchial hyperresponsiveness. In the present study, induced sputum and acetylcholine and capsaicin challenges were assessed in four groups of adult subjects: allergic rhinitis (AR), allergic rhinitis with lower airway symptoms (ARLA), mild stable asthma (BA), and healthy volunteers (C) to correlate lower airway inflammatory markers with bronchial and cough reactivity. Patients with AR (n = 13) and ARLA (n = 11) did not take any anti-inflammatory drugs. Those with BA (n = 9) used inhaled corticosteroids and C (n = 10) were respiratory symptoms free. The patients underwent capsaicin cough challenge and sputum induction with hypertonic saline during the first visit, and acetylcholine bronchial challenge on a separate day. We found that the percentage of eosinophils in induced sputum was significantly higher in patients with AR, ARLA, and BA than in C 14.5 +/-1.8(SE) vs. 13.5 +/-2.9 vs. 13.9 +/-4.0 vs. 3.6 +/-0.8 %, respectively (P=0.012). In contrast, acetylcholine PD(20) in patients with AR, ARLA, and BA was significantly lower than in C 5.6 +/-0.9 vs. 4.1 +/-0.4 vs. 2.8 +/-0.4 vs. 12.9 +/-2.7 mg, respectively (P=0.0001). Neither the eosinophil percentage nor PD20, nor cough sensitivity appreciably differed across the patients groups. Sputum eosinophils correlated significantly with the acetylcholine PD(20) (r=0.37, P=0.016). We conclude that eosinophilic inflammation of lower airways and increased bronchial reactivity were present in adult patients with allergic rhinitis.