No abstract

Background: Small airway dysfunction (SAD) is considered as a precursor of chronic airway diseases (such as COPD, asthma, etc.). As we all known, patients with COPD and asthma both exhibit infiltration of inflammatory factors in the small airways and alveoli. However, few studies have determined whether SAD is associated with airway inflammation and systemic changes in inflammatory factors. To determine whether there are changes in airway inflammation and systemic inflammatory factors in SAD population. Methods: A total of 870 subjects from Shaanxi Province, China were selected from June 2019, to April, 2021. The airway inflammation of SAD was assessed by detecting exhaled NO in the nose, air duct, small airway, and alveoli. Serum levels of inflammatory cytokines including Th1 cytokines IFN-γ and IL-2, Th2 cytokines IL-4 and IL-6, and Th17 cytokines IL-17 and TNF-α were determined by ELISA. Results: The values of FeNO200 (small airway) of SAD, Pre-SAD and Post-SAD were all higher than those of the normal group (P=0.012, P=0.04, P=0.037, respectively). CaNO (alveolar) of SAD, Pre-SAD and Post-SAD were all higher than those of the normal group (all P<0.0001). For Post-SAD, IL-4 is higher than normal group (P=0.034). IL-6, IL-17 and TNF-α in SAD, Pre-SAD and Post-SAD were both higher than those in the normal group (all P<0.05). Conclusion: Patients with SAD have airway inflammation and change of systemic inflammatory factors.