Interleukin 8 and bronchial eosinophils in patients with asthma and cold airway hyperresponsiveness

Abstract

   Introduction. Cold airway hyperresponsiveness (CAHR) is common in patients with asthma. The effect of inhaled corticosteroid/long-acting β2-agonist therapy (ICS / LABA) on its severity, and the role of IL-8, and the eosino-philic profile of bronchial inflammation have not been studied.   Aim. To study the dynamic relationship between the level of IL-8 and eosinophilic inflammation in the bronchi of asthma patients with CAHR using anti-inflammatory combined therapy with ICS / LABA.   Materials and methods. Patients with asthma (n=59) received ICS / LABA for 24 weeks. The level of disease control (ACT, points), cellular composition of induced sputum (IS), bronchial response (ΔFEV1IHCA, %) to 3-minute isocapnic hyperventilation with cold (-20ºС) air (IHCA) was assessed. Exhaled breath condensate (EBC) was collected before and after the IHCA, in which the concentration of IL-8 (pg/mL) was determined.   Results. Group 1 included 28 patients with CAHR (ΔFEV1IHCA = -14.1 ± 1.7%), group 2 included 31 patients with no response to cold bronchoprovocation (ΔFEV1IHCA = - 3.0 ± 2.4 %, p < 0.0001). Initially, patients of groups 1 and 2 had no differences in ACT (16.8±0.6 and 15.7 ± 0.8 points), FEV1 (92.5 ± 3.6 and 87.8 ± 2.2%), the number of eosinophils in sputum (8.0 ± 2.4 and 4.7 ± 1.3%, respectively, p > 0.05). The concentration of IL-8 before and after the IHCA test in group 1 was 131.2 ± 18.0 and 146.3 ± 23.5 pg/mL, respectively (p > 0.05), in group 2 it was 130.5 ± 8.8 and 149.9 ± 18.4 pg/mL, respectively (p>0.05). After treatment, the airway response to the IHCA significantly decreased in group 1 (ΔFEV1IHCA = - 8.8 ± 1.5 %, p < 0.01), in group 2 it remained unchanged (- 3.6 ± 1.3 %, p > 0.05). The level of asthma control in group 1 increased to 20.7 ± 1.6 ACT points (p < 0.01), in group 2 – up to 19.7 ± 1.7 (p < 0.05). The lung function did not change. After treatment, the level of IL-8 before and after the IHCA in group 1 did not change (89.8 ± 11.7 and 85.5 ± 7.8 pg/mL, p > 0.05), as did the number of eosinophils (8.0 ± 2.4 and 6.2 ± 3.1 %, p > 0.05). In group 2, the level of IL-8 before and after IHCA decreased from 89.2 ± 7.7 to 73.9 ± 10.3 pg/mL (p < 0.01), the concentration of eosinophils decreased from 4.7 ± 1.3 up to 1.5 ± 0.57 % (p < 0.05).   Conclusion. 24-week therapy with ICS/LABA in patients with CAHR leads to improved asthma control, a decrease in the severity of cold bronchospasm, without being accompanied by changes in the level of IL-8, which affects the dynamics of the concentration of eosinophils in the bronchi.