Fractional exhaled nitric oxide concentration is increased in asbestosis and pleural plaques

Objective and background:  Asbestos exposure induces generation of reactive oxygen and nitrogen species. Nitric oxide is involved in asbestos‐related lung toxicity in vitro and can be measured non‐invasively in humans in exhaled breath. The authors hypothesized that fractional exhaled nitric oxide concentration (FE NO ) would be increased in subjects with asbestos‐related lung disorders. Methods:  FE NO was measured in 56 subjects with asbestos‐related disorders (asbestosis: 12; pleural plaques: 32; asbestos‐related diffuse pleural thickening: 12) and in 35 normal subjects. The authors also measured exhaled carbon monoxide, another marker of lung inflammation. Results:  Median (25–75 percentile) FE NO was increased in subjects with asbestosis (7.9 (6.6–15.7) p.p.b.; P  = 0.001) and pleural plaques (6.3 (5.3–9) p.p.b.; P  = 0.03) compared with normal controls (4.6 (3.5–6) p.p.b.) ). Subjects with DPT had a median FE NO of 5.6 p.p.b., similar to controls. No significant differences in exhaled carbon monoxide were observed between controls (1.0 ± 0.3 p.p.m.) and subjects with asbestosis (1.3 ± 0.3 p.p.m.), pleural plaques (1.2 ± 0.3 p.p.m.) or diffuse pleural thickening (1.1 ± 0.3 p.p.m.). Conclusions:  FE NO is raised in asbestosis consistent with lung inflammation, and also in pleural plaques.