Discussion
The epithelium of the nasal airway is inhabited by basal, ciliated, and
secretory epithelial cells Similar to epithelium of bronchial airway.19 As such, the nasal airway provides an
readily accessible counterpart to the bronchial airway and may represent
much of the pathology present in the bronchial asthmatic airway. In the
Support of this, roughly 2300 genes expression study in nasal and
bronchial airway brushings revealed a close association between these 2
airway sites. 20
The decision to perform our research on upper rather than the lower
airway epithelium was inspired by its non-invasive sampling, which is
readily applicable in young children. It helps recruiting true pulmonary
disease-free controls, a circumstance which is simply not possible in
researches using bronchoscopic specimen 21.It also helps patients with severe or uncontrolled asthma phenotypes to
be investigated without stopping their long-term inhaled corticosteroid
therapy for asthma, because nasal deposition can be considered as
negligible with the tools used in this study.