The effects of Aspergillus fumigatus challenge on exhaled and nasal NO levels

Several studies have previously shown that exposure to indoor air microbes from moisture-damaged buildings can cause adverse health effects. Aspergillus fumigatus is one of the best-documented moulds causing health problems to those exposed. In this study, inhalation of a commercial A. fumigatus solution was assessed, to establish if it would have effects on fractional exhaled (FeNO) and nasal (FnNO) nitric oxide levels and on lung function. The results were compared with placebo challenge. A total of 28 subjects were divided into three study groups: group 1 had been exposed to occupational mould; group 2 consisted of atopic subjects; and group 3 was a control group. Some 3 h after A. fumigatus challenge, there was a considerable increase in FeNO, and a significant difference was observed between the A. fumigatus and placebo inhalations. The difference was seen in all study groups. No such differences were found in the levels of FnNO or nitrite in nasal lavage fluid. Subjects reported significantly more frequent respiratory tract symptoms after the A. fumigatus inhalation compared with placebo challenge. In conclusion, it was shown here that inhalation challenge of Aspergillus fumigatus elevated fractional exhaled nitric oxide levels. An increase in fractional exhaled nitric oxide may serve as an indicator of respiratory inflammation of acute mould exposure.