Gene therapy hope for allergies and asthma

Life-threatening allergies and asthma could one day be treated by a single injection, say researchers who have successfully treated mice using gene therapy.

Dr Ray Steptoe of the University of Queensland in Australia and colleagues 'turned off' the immune system's memory of an allergen in mice, suggesting that it could be possible for a single treatment to permanently stop the cause of allergic reactions, rather than just managing the symptoms.

The immune system's memory is the underlying cause of both asthma and allergies, as immune cells incorrectly recognise and 'remember' allergens as being potentially dangerous, and mount an immune response. Repeated exposure to an allergen can cause increasingly severe and potentially fatal reactions. However, it is extremely difficult for potential therapies to contend with the permanence of immune memory.

The researchers worked with mice who were allergic to a protein found in egg white. They first inserted a gene which regulates the egg white protein into blood stem cells then transplanted these modified stem cells into the allergic mice. Transplanting the modified stem cells was enough to remove the mice's immune memory of the egg white protein as an allergen, meaning that the animals were no longer sensitive to the protein.

'We have now been able "wipe" the memory of these T-cells in animals with gene therapy, de-sensitising the immune system so that it tolerates the protein,' said Dr Steptoe. 'This research could be applied to treat those who have severe allergies to peanuts, bee venom, shell fish and other substances.'

But the findings should be treated with some caution, given the early stages of the research, note some. Professor Adnan Custovic at University College London told The Independent: 'A mouse model is not the same as a human model … We can cure allergies in mice but we cannot do it in humans … the mechanisms are not identical. Only time will tell whether this approach will be a viable one.'

The researchers are now working on making the treatment simpler and safer and it is hoped that human trials could begin in as little as five years.

Asthma is a major public health issue with some 5.4 million people in the UK with the condition; costing the NHS £1 billion annually. As allergies play a significant role in around 75 percent of asthma cases, as well as affecting the 44 percent of British adults who have at least one allergy, there is a need to produce effective, long-term treatments for these conditions.

The research was published in JCI Insight.