Abstract
BackgroundAllergic non-asthmatic (ANA) adults experience upper airway symptoms of allergic disease such as rhinorrhea, congestion and sneezing without symptoms of asthma. The aim of this study was to utilize PET-CT functional imaging to determine whether allergen challenge elicits a pulmonary response in ANA subjects or whether their allergic disease is truly isolated to the upper airways.MethodsIn 6 ANA subjects, bronchoalveolar lavages (BAL) were performed at baseline and 24h after instillation of an allergen and a diluent in separate lung lobes. After instillation (10h), functional imaging was performed to quantify and compare regional perfusion, ventilation, fractional gas content (Fgas), and glucose uptake rate (Ki) between the baseline, diluent and allergen lobes. BAL cell counts were also compared.ResultsIn ANA subjects, compared to the baseline and diluent lobes, perfusion and ventilation were significantly lower in the allergen lobe (median [inter-quartile range], baseline vs. diluent vs. allergen: Mean-normalized perfusion; 0.87 [0.85–0.97] vs. 0.90 [0.86–0.98] vs. 0.59 [0.55–0.67]; p<0.05. Mean-normalized ventilation 0.89 [0.88–0.98] vs. 0.95 [0.89–1.02] vs. 0.63 [0.52–0.67], p<0.05). In contrast, no significant differences were found in Fgas between baseline, diluent and allergen lobes or in Ki. Total cell counts, eosinophil and neutrophil cell counts (cells/ml BAL) were significantly greater in the allergen lobe compared to the baseline lobe (all P<0.05).ConclusionsDespite having no clinical symptoms of a lower airway allergic response (cough and wheeze) allergic non-asthmatic subjects have a pulmonary response to allergen exposure which manifests as reduced ventilation and perfusion.
Highlights
Allergen exposure in allergic non-asthmatic (ANA) adults causes upper airway symptoms such as sneezing, rhinorrhea and nasal and/or sinus congestion
The aim of this study was to utilize PET-CT functional imaging to determine whether allergen challenge elicits a pulmonary response in ANA subjects or whether their allergic disease is truly isolated to the upper airways
Despite having no clinical symptoms of a lower airway allergic response allergic non-asthmatic subjects have a pulmonary response to allergen exposure which manifests as reduced ventilation and perfusion
Summary
Allergen exposure in allergic non-asthmatic (ANA) adults causes upper airway symptoms such as sneezing, rhinorrhea and nasal and/or sinus congestion. Regional reductions in perfusion, ventilation, lung aeration and elevated glucose metabolism occurred in the allergen exposed lobe compared to the control lobes [6]. These findings suggest that the allergic inflammatory response in the lower airways of AA subjects results in clearly identifiable physiological changes that may account for the pulmonary symptoms in these subjects. Given that ANA subjects, following allergen exposure, exhibit symptoms of an upper airway allergic response without pulmonary symptoms, it is reasonable that they may not experience the reductions in perfusion, ventilation, lung aeration and elevated glucose metabolism that occur in AA subjects. The aim of this study was to utilize PET-CT functional imaging to determine whether allergen challenge elicits a pulmonary response in ANA subjects or whether their allergic disease is truly isolated to the upper airways.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
