Cytokines are polypeptide mediators which act as communication signals among cells of the immune system as well as among other cells and tissues in the body. They are a heterogeneous and complex group and include interferons, tumor necrosis factor and chemokines. They play a key role in homeostasis and in host defense and are involved in such inflammatory and autoimmune diseases such as rheumatoid arthritis as well as infectious diseases such as HIV...