Extracellular Vesicles in Autoimmune Diseases: From Diagnostic Biomarkers to Engineered Therapeutics

ABSTRACT Autoimmune diseases (ADs) are chronic disorders caused by a breakdown in immune self‐tolerance, triggering aberrant immune attacks against one's own tissues. These responses cause persistent inflammation and multiorgan damage. As the global prevalence of ADs continues to increase, they impose a growing public health burden, but current treatments do not meet clinical needs. Extracellular vesicles (EVs) are lipid bilayer membrane‐enclosed nanoparticles secreted by live cells that can carry diverse bioactive molecules and play essential roles in intercellular communication. Recently, EVs have attracted considerable attention as promising therapeutic candidates for ADs owing to their high biocompatibility, low immunogenicity, and ability to traverse biological barriers. This review systematically summarizes the current applications and development trends of both plant and mammalian sources and explores the functions of natural or engineered EVs in modulating the pathological processes underlying ADs. We also discuss the emerging potential of EVs as diagnostic biomarkers and targeted drug delivery systems for autoimmune conditions. Although clinical translation of EV‐based therapies faces challenges, deepening our understanding of the pathogenic roles of EVs in autoimmunity coupled with ongoing advances in bioengineering technologies holds promise for delivering novel theoretical insights and practical strategies for diagnosing and treating these refractory diseases.