Clinical Utility Of The Exhaled Nitric Oxide (NO) Measurement With Portable Devices In The Management Of Allergic Airway Inflammation And Asthma

Figures & data

Figure 1 The mechanism of biosynthesis of NO in allergic airway inflammation. The main biosynthesis of NO in the airways is induced by iNOS presenting in respiratory epithelial cells and inflammatory cells (basophils, eosinophils, neutrophils, mast cells, B or T lymphocytes). Intracellularly produced NO will diffuse to the lumen of the airways. Hyperreactivity of iNOS caused by allergic inflammation induces high level of exhaled NO concentration in the airways.

Abbreviations: FENO, fractional concentration of nitric oxide; NO, nitric oxide; iNOS, inducible nitric oxide synthase; NF-kB, nuclear factor-kappa B; TSLP, thymic stromal lymphopoietin; FcεRI, high-affinity IgE receptor; Treg, regulatory T cell; PGD2, prostaglandin D2; LTD, leukotriene D; LTE, leukotriene E; IL, interleukine.

Figure 2 Origin of nasal NO and technique of nNO measurement. Exhaled NO is produced from the epithelial cells, eosinophils, mast cells, and other cells under the activity of iNOS during contact with allergens. The measurement of nNO is done by introducing the sampling catheter to the nasal cavity via the nostril to aspirate the internal air stream.

Abbreviations: nNO, nasal nitric oxide; FENO, fractional concentration of nitric oxide; iNOS, inducible nitric oxide synthase.