Novel perspectives on extracellular vesicles in autoimmune diseases: immunogenicity, inflammation, and immune surveillance.

Cells release extracellular vesicles (EVs) with cargo that originates from distinct subcellular compartments, including the nucleus, cytoplasm, and plasma membrane. Given their diverse cargo, EVs play multiple roles in physiology and pathology, including in immune dysregulation and autoimmune pathogenesis. For example, EVs can act as autoantigens by transporting immunogenic molecules from the nucleus or cytoplasm, whereas EVs carrying membrane-bound MHCs from antigen-presenting cells can activate adaptive immunity by presenting self-antigens to T cells. EV-associated cytoplasmic peptidases or proteasomes contribute to immune regulation by modulating antigen processing and presentation. Moreover, EVs also drive inflammatory responses by shuttling a variety of proinflammatory molecules that sustain autoimmune responses. Intriguingly, emerging evidence indicates that EVs might contribute to autoimmune surveillance by activating cytosolic surveillance sensors, modulating immune checkpoints, regulating NK/T cell cytotoxicity, and altering macrophage and DC phagocytosis, representing an exciting and underexplored frontier in autoimmune research. By tackling critical knowledge gaps, this Review explores the emerging roles of EVs and their diverse cargo in driving autoimmune diseases, suggesting new perspectives on their potential as innovative therapeutic targets.