TNF and rheumatoid arthritis: One of the major cytokines whose level is elevated in RA is tumour necrosis factor (TNF), and the key role that TNF plays in this scenario is highlighted by the fact that reduction of TNF levels alone, in the bloodstream and other body fluids, using anti-TNF monoclonal antibodies, is enough to reduce dramatically the symptoms of rheumatoid arthritis in the clinic [16].