TNF is a chemical made by the body’s immune system. When it is made in the joints it causes the process of inflammation and joint damage, as seen in rheumatoid arthritis. It was first discovered many years ago in experiments on cancer, where it was found to cause cancer cells to die, and so it was called Tumour Necrosis (i.e. the death of a piece of bone or tissue) Factor. In some patients with arthritis, treatment with anti-TNF removes the TNF from the joints and diminishes the inflammation. Whilst the results of using these drugs, Infliximab (Remicade) and Etanercept (Enbrel) are encouraging, they are not suitable for everyone.