Phagocyte population in the inflammatory pattern of the bronchi of asthma patients regulated by interleukin-17A and interferon-gamma during the airway response to a cold stimulus

Abstract

Introduction. Based on the common effector functions of polymorphonuclear neutrophils and macrophages as phagocytic cells, their role in the formation of an acute reaction of the respiratory tract to a cold stimulus in patients with asthma is of concern.Aim. The study of the concentration of phagocytes, IL-17A and IFN-γ in the inflammatory pattern of the bronchi of asthma patients depending on the airway reaction to a cold stimulus.Materials and methods. 129 patients with asthma were examined. The design of the study included questioning patients using a validated questionnaire Asthma Control Test (ACT, Quality Metric Inc., 2002), collection of induced and spontaneously produced sputum, exhaled breath condensate (EBC), bronchoprovocation test with a 3-minute isocapnic hyperventilation with cold (-20ºС) air (IHCA) with an assessment of the airway response (ΔFEV1) by spirometry.Results. Group 1 (n=55) included individuals with ΔFEV1 -10% and below, group 2 (n=74) – with ΔFEV1 above -10%: -15 (-21; -11) and -3.7 (-6.1; -0.38)%, respectively (p=0.0002). According to the level of ACT (17 [13; 21.5] and 19 [14; 22] points) and indicators of lung function (FEV1 [93.0±2.4 and 97.1±2.4%] and FEF25-75 [63.5±3.5 and 72.0±3.7%]), the patients had no significant intergroup differences. The pattern of bronchial inflammation in group 1 was mixed (neutrophils ≥40%), in group 2 – eosinophilic. In response to the IHCA test, the number of neutrophils significantly increased in the sputum of patients in group 1, the number of macrophages and the number of structurally intact epithelial cells decreased, in proportion to this, the level of IFN-γ and IFN-γ-inducible protein IP-10 (CXCL10) increased in the EBC in relation to patients of the 2nd group. A direct relationship was found between baseline concentrations of IP-10 and IFN-γ (Rs=0.7; p<0.01) in EBC.Conclusion. The airway response to a cold stimulus of patients with asthma is accompanied by functional activation of phagocytic cells with an escalation of neutrophilic inflammation and a decrease in the number of macrophages infiltrating the bronchi associated with an increase in the concentration of IFN-γ, which stimulates the processes of respiratory burst and triggers cell destruction and cytolysis.