Impact of IgE sensitization and rhinitis on inflammatory biomarkers and lung function in adolescents with and without asthma

Both allergic and non-allergic rhinitis are associated with worse asthma control. However, it is unclear how IgE sensitization and/or rhinitis are associated with lung function. We therefore evaluated the effect of rhinitis and sensitization on lung function, including the periphery of the airway system, and inflammatory biomarkers in individuals with and without asthma.

Participants in the BAMSE longitudinal birth cohort study underwent measures of spirometry, impulse oscillometry, and FeNO at age 16 years. Questionnaires were used to obtain data on asthma and rhinitis. Blood samples were analyzed for eosinophils and allergen-specific IgE.

Groups based on the combination of asthma, rhinitis, and sensitization were compared to a healthy reference group. Lower FEV₁ /FVC levels were seen for groups with asthma only (adjusted mean difference -2.8% units (95% CI -4.7; -1.0), P < 0.01), asthma with sensitization (-2.0 (-3.9; -0.2), P < 0.05), and asthma with sensitization and rhinitis (-2.5 (-3.6; -1.4), P < 0.001). The index of peripheral airway resistance R_5-20 was higher in groups with asthma and sensitization (adjusted median difference 94.9 Pa L^-1  s^-1 (95% CI 60.4; 129.3), P < 0.001), as well as asthma with sensitization and rhinitis (36.9(15.0; 58.8), P < 0.01). These groups also had increased FeNO and blood eosinophil levels.

We found signs of peripheral airway obstruction and increased levels of inflammatory biomarkers in the presence of allergic asthma, irrespective of rhinitis status. Despite having a reduced FEV₁ /FVC, peripheral airway engagement was not seen in non-sensitized adolescents with asthma. We suggest that small airway disease is a feature related to the eosinophilic inflammation in allergic asthma in adolescence.