[Lower airway abnormalities in patients with allergic rhinitis]

Objective: To investigate the characteristics of lower airway abnormalities in allergic rhinitis(AR) patients without asthma. Methods: Between June 2008 and December 2012, 377 consecutive AR patients and 264 healthy subjects were recruited. All subjects underwent meticulous history taking, nasal examination, allergen skin prick test, blood routine test, serum total immunoglobin E assay, induced sputum cell count and differentials, measurement of fractional exhaled nitric oxide (FeNO) and bronchial challenge test. Results: The positive rates in AR patients was 12.2%(46/377) for bronchial provocation test, 49.2%(185/377) for FeNO, 39.0%(147/377) for sputum eosinophilia, 15.6%(40/377) for peripheral blood eosinophilia and 55.4%(209/377) for increased serum total IgE levels, which were consistently and statistically higher than those of healthy controls(P<0.01). The levels of FeNO [35.0 (21.8, 65.9)ppb], induced sputum eosinophil percentage [2.0 (0.0, 7.5)%], peripheral blood eosinophil percentage [2.9 (1.8, 4.5)%] and serum total IgE [178.4 (63.1, 384.0)kU/L] in AR patients were also higher(P<0.01). Compared with healthy controls, patients with AR demonstrated lower levels of FEV₁/FVC%, MMEFpred%, MEF₇₅ pred%, MEF₂₅pred% (all P<0.05). Statistical analysis showed that FeNO, ratio of induced sputum eosinophil percentage and peripheral blood eosinophil percentage had significant correlations with each other(P<0.01), the r value being 0.247, 0.235, 0.355 respectively. Conclusion: AR without asthma is characterized by lower airway inflammation, small airway impairment and bronchial hyperreactivity, features similar to those of asthma.