Tumor Necrosis Factor is a type of signaling molecule (cytokine) involved in inflammation. It has been found to be an important factor in a variety of disease processes, because it promotes the inflammatory response which, although necessary in fighting infection, can be deadly in the case of overreaction, as in asthma. Finding this association has been a breakthrough in treating treatment-resistant asthma (refractory asthma).

In 2005, an article was published in the journal Thorax suggesting that severe, refractory asthma could be treated by blocking TNF alpha production using the drug etancercept. After a pilot study significant improvement was experienced by the 15 patients who had poor response to other treatments.

Since 2005, there have been other studies confirming this link. A study published in Expert Opinion on Therapeutic Patents in 2008 discusses a successful method of treating asthma, COPD, pulmonary fibrosis and lupus using a combination of a TNF-alpha antagonist and a CXCL13 antagonist (another cytokine).

An article published in Allergy in 2008 shows an reaction to steroids (a common treatment for asthma which may actually promote TNF-alpha mediated inflammation in some cases.

An article in Current Allergy and Asthma Reports in 2007 summarizes recent research which "provides support for the concept that blocking TNF-alpha activity represents a new approach in asthma therapy. "

Other research has shown that although genetic variation that affects production of TNF alpha and TNF beta have been associated with asthma susceptibility, parental smoking and childhood exposure to ozone can overwhelm such differences because of the strong influence secondhand smoke and ozone can have on TNF expression. (Envrionmental Health Perspectives, 2007)