The major discovery, published in the New England Journal of Medicine, identified a protein called C/EBP- , which is missing in asthmatics and stops muscle cells in the airway from multiplying rapidly and causing breathing restrictions.

In a trial with 54 subjects - 20 with asthma, eight with emphysema, and 26 control subjects - the researchers found that C/EBP “ slows down the production of muscle cells that cause narrowing of the airways in asthmatics.

Professor Judy Black (Pulmonary Cell Research Group, Pharmacology) and Associate Professor Michael Roth (Woolcock Institute), in collaboration with a team from the University Hospital of Basel, Switzerland, introduced the protein into cell cultures taken from asthmatic patients and found that cell growth decreased.

The researchers found that the lack of C/EBP “ in the bronchial muscle cells of asthma sufferers meant they did not have an anti-proliferative response to treatment with anti-inflammatory drugs. However, the drugs were able to block the release of pro-inflammatory factors in cells from asthma patients and of controls.

The protein occurs naturally in the lungs of non-asthmatics, controlling cell proliferation. But in asthmatics, the growth of muscle cells is up-regulated resulting in an increased mass of smooth muscle cell bundles. This may lead to a pathologic narrowing of their airways upon inhalation of asthma triggers, making it difficult to breathe.

While common anti-asthma drugs relieve the symptoms of lung inflammation, the discovery offers hope that the disease can be treated at its root.

Professor Roth said the research team had been working on this project since 1998 and the next phase of their research would be to attempt to re-activate the protein expression in asthma sufferers.

"Synthetic production of the protein or gene therapy do not seem to be viable solutions so we are looking at ways to stimulate its production in asthmatics," he said.

Asthma affects up to 10 per cent of the world's population, killing about 400 Australians a year. Asthmatic attacks can be triggered by various causes including exposure to dust mites, pollen, cold air, changes in humidity and exercise.

It is also the most common reason for visits to the doctor, accounting for about 3 per cent of visits between 1998 and 2002.

The Woolcock Institute is one of Australia's leading research bodies into respiratory diseases like asthma, cystic fibrosis, chronic bronchitis, emphysema, and sleep apnoea. It is currently conducting a winter appeal to raise funds for its research.

To make a tax-deductible donation to the appeal see the Woolcock Institute website.