Updated project metadata. Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic synovial inflammation and cartilage/bone damage. Cytokines like IL-1 and TNF, play a crucial role in the pathophysiology of RA but have limited diagnostic and prognostic value. Recently, extracellular vesicles (EVs) have gained attention in the pathogenesis of this disease, but which processes they reflect in RA is unknown. Therefore, we identified and quantified proteins in plasma-derived EVs from RA patients (RA-pEVs) by mass spectrophotometry (MS) and compared these proteins to pEVs from healthy controls (HC). The observed RA-pEV proteins were coupled to clinical or laboratory parameters to investigate which RA disease process is reflecting by circulating EVs.