Extracellular Vesicles Are Prevalent and Effective Carriers of Environmental Allergens in Indoor Dust

The global incidence of allergic diseases is rising and poses a substantial threat to human health. Allergenic proteins released by various allergenic species play a critical role in the pathogenesis of allergic diseases and have been widely detected in the environmental matrix. However, the release, presence and interaction of environmental allergens with human body remain to be elucidated. In this study, we reported the widespread of allergen-harboring extracellular vesicles (EVs) in indoor dust from 75 households across five provinces in China. Particle size and abundance of EVs were correlated with specific environmental factors. EVs showed long persistence and high resistance to environmental stress. Metagenomics and metaproteomics data revealed that most indoor allergenic species released allergens within the EVs into dust. A higher abundance of allergenic species and their derived EVs was observed in urban areas compared to rural areas. ELISA confirmed the allergenic activity of the EV-associated allergens. Allergens are common components and even markers of EVs, as evidenced by the data compilation of various allergenic species. The proportion of EV-associated allergens varied across species. EVs facilitated allergen entry into epithelial cells. Intranasally administered EVs can be rapidly transported to the lungs and gastrointestinal tract. EV-associated allergens exhibited higher allergenicity compared with non-EV allergens. Our findings elucidate a vesicle pathway through which environmental allergens are released, persist, and trigger allergic responses within EVs.