Adalimumab (HUMIRA, Abbott) is the third TNF inhibitor, after infliximab and etanercept, to be approved in the United States. Like infliximab and etanercept, adalimumab binds to Tumor necrosis factor-alpha (TNF), preventing it from activating TNF receptors. Adalimumab was constructed from a fully human monoclonal antibody, while infliximab is a mouse-human chimeric antibody and etanercept is a TNF receptor-IgG fusion protein. TNF inactivation has proven to be important in downregulating the inflammatory reactions associated with autoimmune diseases. As of 2008 adalimumab has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, moderate to severe chronic psoriasis and juvenile idiopathic arthritis.