Tumeoral Necrosis Factor alpha or TNF in a cytokine. Cytokines are substances released by the body during the inflammatory process. Inflammation is a normal phenomenon generated by the body to fight harmful bacteria and viruses. Normally, this inflammation is controlled and regulated, but in Rheumatoid Arthritis (RA) control this process does not work completely. TNFa is a cytokine particularly potent because it triggers the release of other cytokines in the body. Blood and joints of RA patients harbor a high amount of TNF. Research has shown that overproduction of TNF can cause inflammation and joint damage. Consequently, blocking TNF can reduce inflammation and slow joint damage.