Acute respiratory illness (ARI) is the leading cause of asthma exacerbations yet the mechanisms underlying this association remain unclear. To address the deficiencies in our understanding of the molecular mechanisms driving ARI-induced asthma exacerbations, we undertook a transcriptional profiling study of the nasal mucosa over the course of ARI amongst individuals with a history of asthma, allergic rhinitis and no underlying respiratory disease. We found that ARI is characterized by dynamic, time-specific transcriptional profiles whose magnitudes of expression are influenced by underlying respiratory disease and the mucosal repair signature evoked during ARI. Most strikingly, we report that asthmatics that experience ARI-induced exacerbations are characterized by a reduced but prolonged inflammatory immune response, inadequate activation of mucosal repair and the expression of a newly described exacerbation-specific signature. Findings from our study represent a significant contribution towards clarifying the complex molecular interactions which typify ARI-induced asthma exacerbations.
Overall design
Upon the onset of ‘common cold’, volunteers were instructed to attend the first of three required visits to the study clinic. The first and second visits were designed to obtain samples and clinical data during the early and late stages of symptomatic illness respectively, whereas the third visit would occur when volunteers were asymptomatic and serve as a prospective baseline (BL) for the study.
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