Exacerbation of asthma and neutrophil-dominated airway inflammation in patients with cold-induced airway hyperresponsiveness

Background. Neutrophils can play a significant role in the formation of bronchial inflammation in asthma exacerbation in patients with cold-induced airway hyperresponsiveness (CIAHR).Aim. To evaluate the role of neutrophils in the dynamics of the inflammatory pattern of bronchi in the exacerbation of asthma in patients with CIAHR.Materials and methods. In 31 patients (average age (37.2 ± 2.7) years) with persistent bronchial asthma (BA) with moderate exacerbation and previously established cold-induced airway hyperresponsiveness during cold air isocapnic hyperventilation (– 20 ºC, 3 min) (CAIH), the level of asthma control (Asthma Control Test (ACT), score) and external respiration (forced expiratory volume in the first second (FEV1), forced expiratory flow between 25% and 75% of the vital capacity (FEF25–75)) were assessed; induced sputum (IS) was examined initially and after 24 weeks of follow-up. At the time of the examination, the patients were additionally prescribed prednisone orally (at a maximum dose of 30 mg) for the first 10 days in order to stop the exacerbation, and then they continued treatment with a combination of budesonide / formoterol (640 / 18 μg per day) for 24 weeks.Results. At the time of the initial examination, the ACT score was 17.0 (13.0; 19.5), FEV1 was 89.1 ± 3.9%, and the number of neutrophils in the sputum was 55.9 ± 5.6%. At the end of treatment, the ACT score was 22.0 (17.0; 24.5) (p = 0.037), FEV1 was 96.2 ± 2.9% (p = 0.038), the number of neutrophils in IS decreased, but remained high enough (40.0 ± 5.5%; p = 0.048); and the number of eosinophils did not change. A linear regression equation was made reflecting the relationship between the initially high number of neutrophils in the sputum, other cellular elements in the sputum, the level of asthma control, and the degree of severity of the bronchial response after a bronchoprovocation test with CAIH.Conclusion. Asthma exacerbation in patients with CIAHR is associated with an increase in the neutrophil pool of the bronchial inflammatory infiltrate and correlates with the degree of severity of the airway reaction to cold bronchoprovocation and the level of asthma control.