Scientists have raised the prospect of developing a vaccine to prevent children getting hay fever or asthma, by showing it is possible to inoculate against the allergies. Writing in the Proceedings of the National Academy of Sciences, Rudolf Valenta and colleagues at the Medical University of Vienna describe how they made a vaccine against tree pollen using a genetically modified version of the same type of pollen.
The problem with immunotherapy, according to Dr Valenta and his colleagues, is that it can it can make things worse rather than better, because people are given what sets off the allergic reaction in the first place.
So the researchers developed a genetically modified version of a major birch pollen allergen and used it to inoculate patients who are allergic to that pollen. In the study, a double-blind, placebo-controlled trial, one group of patients received the vaccine while the other received a placebo, and neither the researchers nor the patients knew which was which.
When they injected the GM pollen, the researchers found it stimulated a set of antibodies that fought allergens and allev-iated symptoms. Volunteers were tested for allergic reactions with a skin test and by blowing pollen into their noses.
The researchers concluded that the results could lead to the development of more effective vaccines for the treatment of the most common forms of allergy and could even be used as a preventative vaccination to stop children developing the allergies in the first place.
The team used GM pollen because they could make it hypoallergenic. Work to develop vaccines using normal pollen can make the condition worse in some patients. The pollen vaccine poses no threat to the environment because the process leaves it unable to cross-pollinate.
Dr Valenta hopes that the first products based on his research will be available in Europe within three to four years.
Proceedings of the National Academy of Sciences, August 2004
First Published in JULY 2005
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