Extracellular Vesicle Biomarkers for Immune Disorders

Abnormalities in the immune system can cause a range of autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and scleroderma. Extracellular vesicles (EVs) play regulatory roles in tissue homeostasis and the maintenance of immune balance; however, they are also involved in the occurrence and development of diseases. The self-tissue components carried by EVs can be used as self-antigen proteins and peptides to form complexes with MHC-I/II and can be used as adjuvants for antigen-presenting cells to trigger and enhance autoimmune responses. These components then activate B cells to produce autoantibodies against self-tissue components. EVs can exist stably in body fluids and have a long half-life. Thus, EVs are good targets for research into the pathogenesis of autoimmune diseases and potential biomarkers for the diagnosis of noninvasive diseases. Some potential EV biomarkers, including EV mRNAs and microRNAs, have been shown to be significantly altered in patients with immune disorders. In this chapter, we review recent advances in EVs in autoimmune disorder-related diseases, such as autoimmune diseases, allergic diseases, and organ transplant rejection, and highlight some state-of-the-art studies on the functions of EVs involved in the development of autoimmune disease.