Analysis of inflammatory characteristics of air passage and small airway dysfunction in patients with bronchial asthma complicated with allergic rhinitis

Objective To analyze the inflammation characteristics of air passage and small airway dysfunction in patients with asthma complicated with allergic rhinitis.

Methods A total of 96 patients with bronchial asthma were selected as study subjects by cross-sectional study, and were divided into allergic rhinitis-asthma syndrome group (38 cases) and bronchial asthma group (58 cases) according to presence or absence of complicating with allergic rhinitis. Asthma Control Test (ACT) scores were evaluated in both groups. The levels of total immunoglobulin E (IgE), eosinophils (Eos), C-reactive protein (CRP) in peripheral blood, interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-17A (IL-17A), and γ interferon in peripheral blood of patients in two groups were detected. The lung function indicatorspercentage of forced expiratory volume in the first second to expected value (FEV₁%pred), percentage of forced expiratory flow at 50% of FVC exhaled to expected value (FEF50%pred), maximum mid-expiratory flow to estimated value (MMEF%pred) were detected. Spearman correlation analysis was used to analyze the correlation between small airway function and airway inflammation.

Results FEV₁%pred, FEF50%pred and MMEF%pred were (55.06±23.12)%, (60.48±21.33)% and (60.34±20.44)% in allergic rhinitis-asthma syndrome group, respectively, which were (69.32±30.63)%, (75.54±26.51)% and (70.26±21.03)%, respectively in the bronchial asthma group (P < 0.05). The levels of total IgE, Eos and CRP in peripheral blood of patients in the allergic rhinitis-asthma syndrome group were higher than those of patients in the bronchial asthma group (P < 0.05). The ACT score of the allergic rhinitis-asthma syndrome group was lower than that of the bronchial asthma group (P < 0.05). The concentrations of serum IL-4 and IL-6 in the allergic rhinitis-asthma syndrome group were higher than those in the asthma group (P < 0.05). However, there were no significant differences in IL-17A and IFN-γ between two groups (P>0.05). Spearman correlation analysis showed that the small airway variables such as MMEF%pred and FEF50%pred in allergic rhinitis-asthma syndrome patients were separately negatively correlated with IL-4 and IL-6, respectively.

Conclusion Asthma patients complicated with allergic rhinitis have more obvious inflammation and small airway dysfunction than patients with bronchial asthma. Small airway function may be affected by airway inflammation.