Exhaled nitric oxide and breath condensate ph in asthmatic reactions induced by isocyanates.
BACKGROUND
We investigated the usefulness of measurements of fractional exhaled nitric oxide (FeNO) and pH of exhaled breath condensate (EBC) for monitoring airway response after specific inhalation challenges with isocyanates in sensitized subjects.


METHODS
Lung function (FEV(1)), FeNO, and pH in argon-deaerated EBC were measured before and at intervals up to 30 days after a specific inhalation challenge in 15 subjects with isocyanate asthma, in 24 not sensitized control subjects exposed to isocyanates, and in 3 nonasthmatic subjects with rhinitis induced by isocyanate. Induced sputum was collected before and 24 h after isocyanate exposure.


RESULTS
Isocyanate-induced asthmatic reactions were associated with a rise in sputum eosinophil levels at 24 h (p < 0.01), and an increase in FeNO at 24 h (p < 0.05) and 48 h (p < 0.005), whereas FeNO level did not vary with isocyanate exposure in subjects with rhinitis and in control subjects. FeNO changes at 24 h positively correlated with corresponding sputum eosinophil changes (rho = 0.66, p < 0.001). A rise in pH was observed in the afternoon samples of EBC, irrespective of the occurrence of isocyanate-induced asthmatic reactions.


CONCLUSIONS
We demonstrated that isocyanate-induced asthmatic reactions are associated with a consistent delayed increase in FeNO but not with the acidification of EBC.
Ferrazzoni
Silvia
S
Department of Environmental Medicine and Public Health, University of Padova, Padova, Italy.
Scarpa
Maria Cristina
MC
Department of Environmental Medicine and Public Health, University of Padova, Padova, Italy.
Guarnieri
Gabriella
G
Department of Environmental Medicine and Public Health, University of Padova, Padova, Italy.
Corradi
Massimo
M
Department of Clinical Medicine, Nephrology, and Health Sciences, University of Parma, Parma, Italy.
Mutti
Antonio
A
Department of Clinical Medicine, Nephrology, and Health Sciences, University of Parma, Parma, Italy.
Maestrelli
Piero
P
Department of Environmental Medicine and Public Health, University of Padova, Padova, Italy. Electronic address: piero.maestrelli@unipd.it.
D000328:Adult; D001249:Asthma / Q000139:chemically induced* / Q000175:diagnosis* / Q000378:metabolism; D001944:Breath Tests; D001985:Bronchial Provocation Tests; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017953:Isocyanates / Q000009:adverse effects*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D009784:Occupational Diseases / Q000139:chemically induced / Q000175:diagnosis* / Q000378:metabolism; D016273:Occupational Exposure / Q000009:adverse effects; D011237:Predictive Value of Tests; D016037:Single-Blind Method; D013997:Time Factors
D017953:Isocyanates; D009569:Nitric Oxide