i) Serum amyloid A: Chondrocytes of RA serve as a source of intra-articular acute-phase serum amyloid A protein that induces MMP production and TNF-α expression in synovial tissue [61,62], promotes peripheral blood mononuclear cells recruitment, angiogenesis [63], and synovial cell proliferation [64]. This evidence concerns the gene TNF and rheumatoid arthritis.