Newborn children whose immune system is damaged by 'crippling' viral infections have a greater risk of becoming asthmatic later in life, according to new US research.

The charity Asthma UK has described the findings, published in journal Nature Medicine, as having "really exciting" potential to help develop ways of preventing asthma.

Researchers from the University of Pittsburgh carried out tests on mice and found infections by respiratory syncytial virus (RSV) stripped immune cells of their ability to calm down inflammation in the lung's airways.

Prof Anuradha Ray and Prof Prabir Ray said: "Infection with RSV leads to a complete loss of suppressive function of the regulatory T cells, after which the mice developed asthma-like symptoms.

"We feel that both prophylactic and therapeutic approaches [to preventing asthma] can be developed. This is especially desirable in infants who have a strong family history of asthma."

Previous studies have shown a link between repeated lung infections with RSV and developing asthma later in life but the reason behind this had never previously been established. 

But these latest experiments showed the virus impaired the ability of a specific part of the immune system, called regulatory T cells, to calm inflammation.

Inflammation is an important part of dealing with an infection but for asthmatics chemicals in air which come from ordinary things like dust mites, pets and mould can trigger an inappropriate inflammatory response.

Malayka Rahman, from Asthma UK, said: "This research provides vital information on how viruses interact with our immune cells and why this might lead to an increased risk of asthma.

"What's really exciting is the potential of these findings to translate into new treatments for asthma in the future."

Posted 09/09/12 by richard.hook@pavpub.com