However, under inflammatory conditions, PEVs enter the synovial fluid and have been identified in synovial fluid and are elevated in rheumatoid arthritis.320 These PEVs are pro-inflammatory, as they may can influence the pathogenesis of rheumatoid arthritis, promoting the migration and invasion of rheumatoid arthritis fibroblast-like synoviocytes by activating the NF-κB pathway mediated via CXCR2 signaling pathway.290 In a state of chronic inflammation, PEVs have the ability to exit the bloodstream and infiltrate the bone marrow microenvironment. The gene discussed is CXCR2; the disease is rheumatoid arthritis.