A molecular key to severe asthma has been discovered that may lead to new diagnostic tests and treatments.

Scientists identified a protein that pushes the disease over a "tipping point", turning a mild underlying condition into one that can potentially kill.

The culprit, found in research on mice with asthma-like symptoms, is an immune system signalling molecule called interleukin 17A (IL-17A).

"This study suggests that at some point it may be possible to treat or prevent severe forms of asthma by inhibiting pathways that drive the production of IL-17A," said lead researcher Dr Marsha Wills-Karp, from Cincinnati Children's Hospital in the US.

Asthma is initially triggered by airborne allergens, such as dust mite particles or pet fur. A process involving IL-17A then builds on itself and sets up an "amplification loop", said the scientists.

The researchers found they could reduce the hyper-responsiveness of mice by blocking the interleukin molecule.

Their findings are reported in the journal Nature Immunology.

Sighted www.currentaffairs.ninemsn.com.au, 30 August 2010