Cure for asthma and allergies moves a step closer

Researchers have discovered a mechanism which can lead to asthma and allergies by interfering with the immune system raising hopes that a cure isn't far away.

The joint British and Swiss research effort has uncovered evidence that a specific gene can lead to a loss of regulation in the immune system that ultimately increases an individual's chances of developing asthma, hay fever and other allergies.

Researchers from Imperial College London, the Swiss Institute of Allergy and Asthma Research in Davos, Switzerland, and a number of other international institutions published the results of their study yesterday in the journal PLoS Biology.

They report that a gene known as GATA-3 can block the development of regulatory T-cells in the immune system by disrupting the function of another gene (FOXP3). The FOXP3 gene is vital to the correct function of regulatory T cells and when it is blocked new regulatory T-cells stop being produced.

In the immune system regulatory T-cells play an important role keeping other cells in check; without them the immune system would run out of control and do severe damage to the body's own tissues. In healthy individuals regulatory T-cells help to prevent allergic reactions by suppressing pro-allergic cells known as Th2 cells.

In those with allergies, the immune system is biased towards a specific response to threats that utilizes these Th2 cells and others associated with them. The immune system wrongly identifies harmless environmental molecules such as pollen, as being a threat and the individual experiences the symptoms of allergy as the immune response to the perceived threat is initiated. Whenever the person encounters this allergen again the same reaction occurs.

With allergies reaching near epidemic proportions it is hoped that the discovery of this genetic mechanism that disrupts healthy immune system regulation will lead to the development of therapies that target the source of allergic conditions and "re-program" the body to have a healthy response when faced with allergens.

Lead researcher, Dr Carsten Schmidt-Weber from the National Heart and Lung Institute at Imperial College London, said: "This finding will help us to understand how healthy individuals are able to tolerate allergens and what we need to do to re-induce tolerance in the immune systems of patients with allergies. We hope that we will soon be able to help not only patients suffering from single allergies, but also those with multiple ones - the atopic patients."”

The researchers were able to reach their conclusions by analysing the genes related to regulatory T-cells and looking at how they interacted with each other. Mouse models were then used to confirm the findings. Mice which were genetically engineered to express the GATA-3 gene in all T cells showed dramatic defects in the production of regulatory T-cells.