Impact of urban air pollution on the allergenicity of Aspergillus fumigatus conidia: Outdoor exposure study supported by laboratory experiments

Understanding the chemical interactions of common allergens in urban environments may help to decipher the general increase in susceptibility to allergies observed in recent decades. In this study, asexual conidia of the allergenic mold Aspergillus fumigatus were exposed to air pollution under natural (ambient) and controlled (laboratory) conditions. The allergenic activity was measured using two immunoassays and supported by a protein mass spectrometry analysis. The allergenicity of the conidia was found to increase by 2-5 fold compared to the control for short exposure times of up to 12h (accumulated exposure of about 50ppb NO₂ and 750ppb O₃), possibly due to nitration. At higher exposure times, the allergenicity increase lessened due to protein deamidation. These results indicate that during the first 12h of exposure, the allergenic potency of the fungal allergen A. fumigatus in polluted urban environments is expected to increase. Additional work is needed in order to determine if this behavior occurs for other allergens.