Irish and US researchers have discovered a marker, which can help determine which asthma patients are likely to benefit from new treatments.

Asthma is a chronic lung disease, which sees the airways in the lungs becoming inflamed, narrow and hyper responsive. Symptoms can include shortness of breath, wheezing, a feeling of tightness in the chest and a chronic cough.

Around 470,000 people in Ireland are affected and symptoms can continue to badly affect some of these despite good treatment.

However, researchers from the Royal College of Surgeons in Ireland, along with colleagues from Stanford University and Oregon Health and Sciences University in the US, have discovered a marker which can help determine which patients are likely to benefit from new treatments which target inflammatory cells known as eosinophils.

These are a type of white blood cell that help to fight disease.

"The novel treatments now available for asthma present a new challenge for clinicians. It is important that we are able to identify which patient will benefit from these treatments. Our research set out to determine if there were any particular markers which would help us to understand which patients had a particular form of asthma and would respond well to new treatments," explained Prof Richard Costello of the RCSI.

He noted that with eosinophilic asthma, which is usually hard to manage, eosinophils in the airway alter nerve function, making the condition worse.

"We identified that inflammatory cells, in particular, eosinophils, promote airway nerve growth in patients with asthma. These observations provide a unique insight into a fundamental mechanism of how the inflammation caused by asthma causes people to experience the symptoms of asthma, such as coughing and breathlessness," Prof Costello said.

He explained that this research means ‘that we now know which markers to look for in a patient with severe asthma'.

"A patient with markers which show they have this particular form of asthma is likely to respond well to these new treatments," he added.

Details of these findings are published in the journal, Science Translational Medicine.