Study links colds to asthma

Scientists have identified a sequence of biological events that could trigger life-threatening asthma attacks in people suffering from colds — a finding that holds the potential for developing more effective medicines.

In a study published in the journal Science Translational Medicine, researchers found that a small molecule, or ‘cytokine’, called IL-25 may play a key role in the effect that viruses causing colds have on people with asthma.

According to the World Health Organisation, 235m people suffer from asthma worldwide and the condition is the most common chronic disease among children. About half a million people in Ireland have asthma and at least one person dies from the disease every week.

Viruses that infect the airways are the most common cause of asthma attacks, accounting for 80%-90% of cases. Most of these are rhinoviruses, which are also the main cause of common colds.

Although illnesses caused by rhinoviruses are usually relatively mild, they can also infect the lungs and, in people with respiratory conditions like asthma, can trigger severe attacks.

“Our research has shown... that the cells that line the airways of asthmatics are more prone to producing a small molecule called IL-25, which then appears to trigger a chain of events that causes attacks,” said Nathan Bartlett, an expert at the Imperial College London’s national heart and lung institute who co-led the study.

He said that by finding a drug to target the molecule at the top of the cascade, “we could potentially discover a much-needed new treatment to control this potentially life-threatening reaction in asthma sufferers”.