ENO levels even in non-asthmatic patients

Laboratory and workplace studies have shown increases in ENO levels even in nonasthmatic patients that are related to exposures such as ammonium bisul-fate, the aluminum smelter potroom work-place, pulp-mill gassing incidents, and in leather workers who have been exposed to sol-vents. In contrast, there was no significant increase in ENO levels postexposure among healthy workers in a swine confinement building. Underground workers, especially those with respiratory symptoms, exposed to particulate matter and nitrogen dioxide, showed elevated levels of ENO compared to outdoor workers, despite a lack of differences in spirometric findings between these two groups. 

Limited numbers of studies have examined the changes of ENO levels in patients with sensitizer-induced OA. Asthma among laboratory animal workers was associated with higher ENO levels compared to asymptomatic laboratory animal workers. Another study found no clear relationship between either positive SIC or elevated specific IgE antibody response and an increase in ENO levels. Among health care Pharmacy workers, latex-sensitized workers showed increased ENO levels at 22 h after a latex chal-lenge, which was significantly related to airflow limitation, though an earlier study had not shown changes with workplace latex exposures. In a group of 40 workers, ENO levels were significantly increased after a positive SIC response in those workers with normal or slightly increased prechallenge ENO levels. After an SIC with diisocyanates, an increase in ENO levels was more likely to develop in challenge responders with baseline airway hyperresponsiveness compared to nonresponders.

Exhaled Breath Condensate: Exhaled breath condensate (EBC) likely contains aerosolized droplets of airway lining fluid and volatile compounds, including hydrogen peroxide, aldehydes, leukotri-enes, prostaglandins, F2-isoprostanes, cytokines, antioxidants, glutathione, and nitrosated species. Studies have reported inconsistent levels of these compounds in EBC, and this topic has been addressed in an American Thoracic Society/Euro-pean Respiratory Society Task Force.