Exhaled nitric oxide levels after specific inahalatory challenge test in subjects with diagnosed occupational asthma.

OBJECTIVES Measuring exhaled nitric oxide (eNO) is a useful method for the assessment of bronchial inflammation in asthmatic subjects. The aim of the study was to evaluate the changes in eNO level in the subjects with suspected occupational asthma (OA) after a specific inhalation test (SIT) with occupational agents. MATERIALS AND METHODS Forty two patients, including 17 farmers, 15 bakers and 10 health care workers had a physical examination, skin prick tests with common and occupational allergens, total serum IgE level, specific anti-allergen IgE determinations, spirometry and SIT. Also, morphological changes in induced sputum (ISP) and nasal lavage fluid (NLF) were analysed and eNO measurements were performed. RESULTS SIT revealed a significant increase in the proportion of eosinophils in NLF and in ISP in the cases with diagnosed OA. Moreover, these cases showed significantly increased eNO levels only 24 h after SIT, compared to the measurements before SIT. We also found a significant correlation between eNO level at 24 h after SIT and the percentage of eosinophils in NLF before, and 4 and 24 h after SIT, as well as in ISP before and 24 h after SIT in all subjects with diagnosed OA. CONCLUSION The findings may confirm the usefulness of exhaled nitric oxide measurements for diagnosing OA.