Finally, a study of ACE2 expression in nasal airway samples obtained from children and adults with allergic rhinitis and asthma reported an inverse relationship between nasal ACE2 expression and allergic status and Th2 biomarkers, including serum IgE, exhaled nitric oxide level, and reduced nasal and airway IL-13 expression and airway ACE2 expression following allergen exposure [10]. Here, IL13 is linked to asthma.