Doctors in Southampton are trialling a pioneering air-cleaning device that could help patients with severe asthma - while they sleep.

The Temperature Controlled Laminar Airflow (TLA) machine, which works by the bedside, filters out allergy particles - known as allergens - which worsen symptoms and trigger attacks when inhaled by allergic individuals.

By removing the particles, which increase at night when body heat and movement carry them from the bedding area to the breathing zone, patients lungs and airways are able to 'rest' in clean air.

Around 10% of the 5.4 million people in the UK with asthma have the most severe form, which leaves them unable to control their symptoms, resulting in frequent attacks - exacerbations - despite taking multiple high-strength medicines.

"While the majority of asthmatics are able to control their symptoms with medication, around one in ten regularly experience life-threatening symptoms and attacks for which currently treatments are insufficient," explained Professor Peter Howarth, a specialist in asthma and allergy at Southampton General Hospital and study co-investigator.

"There is a desperate need for new and innovative treatment options for patients who suffer from severe asthma and this is an extremely exciting device which offers the hope of real progress for this vulnerable patient group."

The £1.2m study, funded by the National Institute for Health Research (NIHR) Health Technology Assessment Programme, will involve 222 adults with half given a TLA device that is working and the other half given an inactive version.

Earlier studies showed the TLA device can reduce exposure to potential allergens by a further 99% when compared to the best in class air cleaner - but experts now want to see if it can reduce asthma attacks and asthma symptoms such as coughing and wheezing. Prof Howarth, who is based at the NIHR Southampton Respiratory Biomedical Research Unit, said: "With such a significant reduction in exposure to allergens, we believe that targeting this equipment specifically to the breathing zone of a patient may succeed in an area where so many other measures, including air filters, have failed.

"By allowing the lungs and airways to 'rest' in clean air overnight, we expect to see a reduction in symptoms which, in turn, will cut the risk of attacks and vastly improve quality of life for these patients as a result."

The trial, known as the LASER study, is being carried out at Southampton General and the Queen Alexandra Hospital in Portsmouth, with sites in Leicester, Liverpool, Birmingham and Bradford also recruiting participants.

Further centres are being established in Hull, Oxford, London and another in Liverpool. Anyone interested in finding out more about the study in Southampton and how to participate can contact the research team by texting LASER and their name to 62277 (texts are free). To contact any of the other research sites, visit http://www.asthma-treatment.org.uk.