Macrophages, as resident professional APCs, have a central role in RA progression by antigen presentation, inflammatory cytokine (e.g., IL-1, -6, -12, -15, -18, -23, tumor necrosis factor (TNF)-α) and destructive molecule production (e.g., prostanoids, reactive oxygen intermediates, nitrogen intermediates) [12]. This evidence concerns the gene TNF and rheumatoid arthritis.