TNF and rheumatoid arthritis: TNF-α is a proinflammatory cytokine that is important for the pathogenesis of RA; it is involved in the pathogenic mechanism of RA, including endothelial cell activation, cytokine induction, white blood cell aggregation, activation of osteoclasts and the destruction of cartilage and bone cells (39) and leads to a continued inflammatory reaction and the progressive destruction of cartilage and bone.