Macrophages appear to play a pivotal role in the pathogenesis of RA because they are present in high numbers in RA synovial tissue and clearly show signs of activation, including enhanced expression of cellular surface markers like major histocompatibility complex class II molecules, pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) [3], chemokines, and matrix metalloproteinases [4]. This evidence concerns the gene TNF and rheumatoid arthritis.