Inflammatory-cellular composition of the induced sputum (IS) and activity of leucocytes myeloperoxidase (MPO) in asthmatics with different airway response to hyperosmolar stimulus

Background: Cellular inflammation plays a role in the formation of airway hyperresponsiveness in asthma. Whether MPO of bronchial leucocytes involved in osmotic airway hyperresponsiveness? Aim: To study cytomorphological picture and activity of leucocyte MPO in IS in asthmatics with different airway response to hyperosmolar stimulus. Methods: In 52 asthmatics (mean age is 40.2±1.1 years) the lung function (FEV 1 ), airway response (ΔFEV 1 ) to 3-min ultrasound inhalation with hypertonic (4.5%) NaCl solution were studied. The activity of leucocytes MPO was defined in cytological smears of IS by the Graham-Knoll method; the optical density of MPO was expressed by mean cytochemical coefficient (MCC) in pixels. The number of cells of bronchial epithelium (%) in the smears of IS was calculated. Results: 19 patients of 1 st group had airway hyperresponsiveness and 33 patients of 2 nd group did not have any response to hyperosmolar challenge (ΔFEV 1 was -17.3±1.6 and -1.5±0.6%, respectively, p st group the level of MCC of MPO was significantly higher than in the 2 nd group (148.4±7.1 and 89.1±7.8, respectively, p st group. Conclusion: The level of MPO of neutrophilic leucocytes can be considered as a marker of formation of bronchial response to hyperosmolar stimulus. Study was supported by Russian Scientific Fund (grant 14-25-0019) .