Airway reflexes such as coughing, sneezing, and the expiration reflex are essential in preventing foreign body from staying in the airway. These defensive reflexes should be appropriately activated against foreign bodies entering both the upper and lower airways. However, excessive responses to airway stimulation can lead to further airway distress and result in complications such as an overactive cough reflex and sneezing.

Allergic airway diseases, such as asthma and allergic rhinitis (AR), are typically chronic and are occasionally characterized by excessive and prolonged Th2 responses to inhaled allergens. They are assumed to be linked to oxidative stress. Asthma is associated with decreased antioxidant defenses, such as superoxide dismutase, catalase, and glutathione. Patients with AR have systemically elevated oxidative stress and systemically elevated serum total antioxidant status levels. Concomitant use of nasal steroids and antihistamines significantly decreases total oxidative stress in AR patients. Significant improvement in clinical outcome was observed in subjects who received antioxidants along with intranasal steroid fluticasone furoate. Other treatments that have been reported to improve symptoms of respiratory allergic diseases by enhancing antioxidant status include hydrogen-rich saline, crocin, curcumin, and silymarin. 

Interleukin (IL)-4 and IL-13 are critical cytokines in the induction of the pathogenic Th2 responses. They induce periostin in the airway tract that is highly expressed in chronic inflammatory diseases―asthma, atopic dermatitis, eosinophilc chronic sinusitis/chronic rhinosinusitis with nasal polyp, and allergic conjunctivitis. 

In this presentation, we will briefly review previous studies regarding airway disorders linked to oxidative stress. We will also introduce our recent project regarding airway hyperresponsiveness and the involvement of periostin in respiratory allergic diseases using periostin-knockout mice and respiratory allergic models. Further studies are necessary to evaluate the possibility of anti-oxidative treatment for the hypersensitivity caused by allergic airway inflammation.