A huge variety of diseases essentially stem from a dysfunctional immune system. Our body's natural defense mechanism can be under-active, resulting in cancer growing unchecked, or our immune system can be over-active, leading to autoimmune diseases such as inflammatory bowel disease or multiple sclerosis. After 10 years of work a new study has revealed for the first time the discovery of a molecule that has been found to modulate the immune system's activity.

Regulatory T cells (Tregs) are a fundamental component of our body's immune system response, acting as a modulator for excessive immune system activity. Tregs essentially work to shut down immune responses and, for example, are often found in high volumes in the microenvironment surrounding tumors, leading researchers to hypothesize they play a role in blocking the body's ability to attack cancers. On the other hand, in the case of autoimmune disease, where the immune system is abnormally overactive and attacks healthy cells and tissues, Tregs are usually seen in unusually low levels.

Until now we did not know exactly what pathway controls Treg activity. The new study describes the discovery of a new metabolic pathway regulated by a molecule called microRNA-142. The researchers revealed this particular molecule seems to be a fundamental master switch for Treg function.

"We were able to trace the molecular fingerprints of this molecule across other genes to determine how it acted as such a critical regulator," explains Richard Jenner, one of the researchers on the project.

Graham Lord, from the University of Manchester and lead researcher on the new study, is optimistic this discovery could be turned into a functional clinical treatment in as little as a few years. It is a somewhat optimistic notion, considering the absolute complexity of the human immune system, the lack of any human testing so far, and the potential complications that could arise from artificially disrupting the immune system.

But, the beneficial implications of this new discovery can certainly not be overestimated. Being able to artificially turn up, or down, the body's immune response could help effectively treat everything from out of control viral infections to hyperactive allergic responses.

"Scientists over the past decade or so have developed therapies which are able to modulate different pathways of the immune system," says Lord. "We hope that this new discovery will lead to the development of new ways to treat autoimmunity, infectious diseases and cancer and we are incredibly excited about where this may lead."

The new study was published in the Journal of Clinical Investigation.