Activated neutrophils are found in the synovial fluid of patients with RA.[51] Hypoxia, antiapoptotic cytokines (such as TNF-α, macrophage colony-stimulating factor, and IL-8), and autoantibodies found in synovial fluid in RA increase neutrophil survival for up to several days and increase their proliferation. This evidence concerns the gene CXCL8 and rheumatoid arthritis.