Low tumor necrosis factor α levels and neutrophil counts in nasal lavage after mold exposure

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The results of allergy tests against molds usually remain negative in patients with upper respiratory tract and conjunctival symptoms after microbial exposure in a water-damaged building. Most mold-exposed persons report nasal irritation. Immune mechanisms of the nasal symptoms have not been fully elucidated. To investigate local inflammatory responses after mold exposure in the upper respiratory tract and the feasibility of nasal lavage in diagnosing work-related exposure. Altogether, 26 mold-exposed and 20 nonexposed workers from the same hospital were selected for the present study. The work premises of the exposed workers had detectable moisture and microbial problems. All exposed workers and their nonexposed controls underwent clinical examination, laboratory tests to detect allergy to molds, and nasal lavage. Inflammatory cells and proinflammatory cytokines were measured in the nasal lavage fluid. Nasal lavages were performed again 6 months after a thorough renovation of the building. In the nasal lavage, the neutrophil count and the level of tumor necrosis factor alpha in the exposed employees were lower, whereas the macrophage and epithelial cell counts were higher than in the control group. After the renovation, no difference was found in inflammatory response between the study group and the control group. The mean concentration of serum IgG to Stachybotrys chartarum was higher in the exposed workers. These results suggest that exposure to toxin-producing microbial growth in a water-damaged building caused immunosuppression in nasal mucosa, leading to a decrease in neutrophil counts and tumor necrosis factor alpha levels. Nasal lavage is a suitable method for examining inflammatory responses in work-related mold exposure.