Nitric oxide and proinflammatory cytokines in nasal lavage fluid associated with symptoms and exposure to moldy building microbes

Epidemiological data indicate that living or working in a moldy building is associated with increased risk of respiratory symptoms and disease related to inflammatory reactions, but biochemical evidence linking cause and effe ct is still scarce. The staff working in a mold-contaminated school, and a reference group without such exposure, were studied. Nasal lavage was perfo rmed and health data were collected with a questionnaire at the end of the spring term, after a 2.5-mo summer vacation, and at the end of the fall ter m. Here we show that concentrations of tumor necrosis factor alpha (TNF-alp ha), interleukin-6 (IL-6), and nitric oxide (NO) in nasal lavage fluid were significantly higher in the exposed than in the control subjects at the en d of the first exposure period. These inflammatory mediators decreased to r eference group concentrations during the period when there was no exposure and the production of NO and IL-6 increased again during the reexposure in the fall term. Reports of cough, phlegm, rhinitis, eye irritation, and fati gue paralleled the changes in the measured inflammatory markers. These resu lts point to an association between inflammatory markers in the nasal lavag e fluid, the high prevalence of respiratory symptoms among the occupants, a nd chronic exposure to molds in the indoor environment.