This study was funded by Centocor Inc.
Original article: Nasal nitric oxide: longitudinal reproducibility and the effects of a nasal allergen challenge in patients with allergic rhinitis
Article first published online: 12 MAR 2007
Volume 62, Issue 4, pages 378–384, April 2007
How to Cite
Boot, J. D., De Kam, M. L., Mascelli, M. A., Miller, B., Van Wijk, R. G., De Groot, H., Cohen, A. F. and Diamant, Z. (2007), Original article: Nasal nitric oxide: longitudinal reproducibility and the effects of a nasal allergen challenge in patients with allergic rhinitis. Allergy, 62: 378–384. doi: 10.1111/j.1398-9995.2007.01328.x
- Issue published online: 12 MAR 2007
- Article first published online: 12 MAR 2007
- Accepted for publication 22 December 2006
- allergic rhinitis;
- nasal allergen challenge;
- nasal nitric oxide;
Background: Exhaled nitric oxide (eNO) is a validated noninvasive marker of airway inflammation in asthma. In patients with allergic rhinitis (AR), increased levels of nasal nitric oxide (nNO) have also been measured. However, the applicability of nNO as a marker of upper airway inflammation awaits validation.
Aim: To test the longitudinal reproducibility of standardized nNO measurements in patients with AR and the effects of nasal allergen challenge.
Methods: Twenty patients with clinically stable, untreated AR participated in a combined study design. First, reproducibility of nNO was tested over 1, 7, and 14–21 days. Subsequently, the effect of nasal allergen challenge on nNO was studied in a placebo-controlled, parallel design. Nasal NO was measured with a chemoluminescence analyzer. Ten subjects randomly underwent a standardized nasal allergen challenge; 10 subjects received placebo. Response to nasal challenge was monitored by composite symptom scores.
Results: There was a good reproducibility of nNO up to 7 days [coefficient of variation (CV) over 1 (16.45%) and 7 days (21.5%)], decreasing over time [CV (14–21 days): 38.3%]. As compared with placebo, allergen challenge caused a significant increase in symptom scores (P < 0.001), accompanied by a decrease in nNO at 20 min postchallenge (P = 0.001). Furthermore, there was a gradual increase in nNO at 7 h, reaching significance at 24-h postallergen (P = 0.04).
Conclusions: Similar to eNO in asthma, nNO is a noninvasive marker, potentially suitable to monitor upper airway inflammation following allergen-induced late response. Present data show a good reproducibility of nNO measurements, decreasing over time, probably because of subclinical seasonal influences.