Extracellular Vesicles in Allergy: From Cellular Communication to Clinical Implications

Extracellular vesicles (EVs) are lipid bilayer-enclosed particles released by both eukaryotic and prokaryotic cells and represent an evolutionarily conserved system of intercellular communication. By transporting bioactive cargo, including proteins, lipids, microRNAs, EVs enable the transfer of molecular signals between cells, thereby regulating immune homeostasis and inflammatory responses. In allergic diseases, EVs have emerged as key mediators linking epithelial barriers, immune cells, and the microbiome. EVs derived from epithelial, immune, and microbiota-associated cells may contribute to the initiation, amplification, and persistence of allergic inflammation by modulating barrier integrity, immune cell polarization, and cytokine signaling pathways. Disease-specific alterations in EV cargo reflect underlying pathogenic mechanisms, positioning EVs as promising non-invasive biomarkers for disease diagnosis, stratification, and monitoring. In parallel, accumulating experimental evidence highlights the therapeutic potential of EVs as cell-free immunomodulatory agents capable of suppressing allergic inflammation and promoting immune tolerance. This review synthesizes current knowledge on extracellular vesicles across three major allergic diseases: asthma, atopic dermatitis, and food allergy, integrating mechanistic insights with diagnostic and therapeutic advances. By incorporating highly recent literature and covering a broad spectrum of EV sources and engineered vesicle-based strategies, the review provides a comprehensive overview of how EV-mediated cellular communication translates into clinically relevant applications in allergy.