We aimed to establish an etiology-based connection between the symptoms experienced by the occupants of a workplace and the presence in the building of toxic dampness microbiota. The occupants (5/6) underwent a medical examination and urine samples (2/6) were analyzed by LC-MS/MS for mycotoxins at two time-points. The magnitude of inhaled water was estimated. Building-derived bacteria and fungi were identified and assessed for toxicity. Separate cytotoxicity tests using human THP-1 macrophages were performed from the office's indoor air water condensates. Office-derived indoor water samples (n = 4/4) were toxic to human THP-1 macrophages. Penicillium, Acremonium sensu lato, Aspergillus ochraceus group and Aspergillus section Aspergillus grew from the building material samples. These colonies were toxic in boar sperm tests (n = 11/32); four were toxic to BHK-21 cells. Mycophenolic acid, which is a potential immunosuppressant, was detected in the initial and follow-up urine samples of (2/2) office workers who did not take immunosuppressive drugs. Their urinary mycotoxin profiles differed from household and unrelated controls. Our study suggests that the presence of mycotoxins in indoor air is linked to the morbidity of the occupants. The cytotoxicity test of the indoor air condensate is a promising tool for risk assessment in moisture-damaged buildings.
Keywords: clinical toxicology; dampness and mold hypersensitivity syndrome; indoor air water; mycotoxins; sick building syndrome; urine.