The effect of omalizumab on small airway inflammation as measured by exhaled nitric oxide in moderate-to-severe asthmatic patients.

Measurement of fractional nitric oxide concentration in exhaled breath (FENO) is a simple, noninvasive method to evaluate eosinophilic airway inflammation. Nitric oxide (NO) arising from peripheral small airways/alveoli (alveolar NO concentration [CalvNO]) can be estimated using multiple flow rates and a two-compartment model of the airways and alveoli. Omalizumab, a monoclonal anti-IgE antibody, is approved for the treatment of allergic asthma and also has been shown to decrease FENO levels.