Updated project metadata. Previously, extracellular vesicles (EVs) from rheumatoid arthritis (RA) synovial fluid (SF) have been reported to stimulate the release of pro-inflammatory mediators in recipient cells. However, mechanistic details are unclear and contaminants in EV enrichments might have compromised previous observations. We recently developed a novel, size exclusion chromatography (SEC)-based method of EV isolation capable of high-quality enrichments from human synovial fluid. Here, we employed this method in combination with high resolution mass spectrometry to accurately characterise the SF EV proteome and investigate contributions of SF EVs to inflammatory processes in RA.