Current application of exhaled nitric oxide in clinical practice Joseph D. Spahn, MD, Jonathan Malka, MD, Stanley J. Szefler, MD  Journal of Allergy and Clinical Immunology  Volume 138, Issue 5, Pages 1296-1298 (November 2016) DOI: 10.1016/j.jaci.2016.09.002 Copyright © 2016 American Academy of Allergy, Asthma & Immunology Terms and Conditions

Fig 1 Concept diagram summarizing the mechanisms and clinical application of exhaled NO measurement. Feno is produced as a consequence of allergic inflammation mediated through IL-13 and IL-4 expression. Allergic inflammation is involved in both the initiation and maintenance of airway inflammation seen in asthmatic patients, whereas less is known regarding the role played by eosinophilic inflammation. Because Feno is a direct measure of local airway inflammation, it is a good marker of inflammation in asthmatic patients and, as a result, has significant clinical utility. Its levels decrease with dupilumab (inhibition of both IL-4 and IL-13), whereas mepolizumab (inhibition of IL-5) has no effect on Feno values, suggesting that these 2 forms of inflammation are not closely linked. AHR, Airway hyperresponsiveness; AW, airway; GC, glucocorticoid; JAK, Janus kinase; LPR, late-phase response. Journal of Allergy and Clinical Immunology 2016 138, 1296-1298DOI: (10.1016/j.jaci.2016.09.002) Copyright © 2016 American Academy of Allergy, Asthma & Immunology Terms and Conditions