MONDAY, Aug. 9, 2004 (HealthDayNews) -- In the first trial of its kind, Austrian researchers have achieved success with an allergy vaccine using genetically engineered pollen.
The findings are reported in this week's issue of the Proceedings of the National Academy of Sciences.
In people with allergies, antibodies go into overdrive, attacking substances, such as pollen or peanuts, which are actually harmless. When the allergen is introduced into the body, the body goes into full battle mode, summoning IgE antibodies to dismantle the perceived threat. It is actually the immune response that causes most of the symptoms of allergies. According to the researchers, IgE is involved in allergies in about 25 percent of the population in industrialized nations.
Allergy shots are commonly used to treat allergies, but they have drawbacks.
According to Dr. Jonathan Field, director of the Pediatric Allergy, Asthma and Immunology Clinic at New York University Medical Center/Bellevue Hospital, the problem with immunotherapy for allergies is that it can elicit an even worse response, because people are given what sets off the allergic reaction in the first place.
"We're always looking to make safer, better forms of treatment," he said.
That's why researchers came up with a genetically modified version of the major birch pollen allergen and used it to inoculate patients who were allergic to this particular pollen. The study was a double-blind, placebo-controlled one, meaning that one group of patients received the vaccine while the other received a placebo, and neither the researchers nor the patients knew what anyone was receiving.
Over the course of one year, 124 adults were tested. Participants received a vaccine before peak birch pollen season then were screened year-round for antibodies that would indicate the presence of an allergic response.
The researchers found an increase in IgG antibodies, which actually inhibit allergic reactions, in the people who had received the vaccine. This was one indication the vaccine was working. The researchers also saw fewer allergic side effects with the vaccine and an improvement in symptoms.
At the same time, there was a decrease in IgE antibodies induced by exposure to birch pollen, indicating that the vaccine was getting at the root case of the disorder.
"We have achieved two major improvements," said study author Dr. Rudolf Valenta, who is with the department of pathophysiology at the Medical University of Vienna. Those improvements are, he added, "therapy with the actual disease-causing molecule and reduction of the risk of inducing allergenic side effects."
"This is exciting in that makes for a potential cure for allergies," Field said. "It has potential for people who can't tolerate allergy shots."
And that potential isn't limited to those who are allergic to birch pollen. "This approach can be applied to any protein allergen," Valenta said. "The same technology is currently being applied for numerous allergen sources. These vaccines have not yet reached clinical evaluation, but the in vitro and animal studies suggest that they will work in the same way."
Field believed the real promise of such a genetically engineered vaccine may be in the realm of life-threatening allergic reactions, such as peanuts.
"Most people don't die of hay fever," he said. "This could be a safe way to treat potentially life-threatening disease, where before avoidance was the only strategy."
Valenta has hopes that go even higher. "My next vision is to use genetically modified allergens not only for therapeutic but also for prophylactic allergy vaccination which could eventually lead to the eradication of the disease," he said.
"I dare to predict that the first products will be registered in Europe at the latest within three to four years," Valenta said.
More information
For more on different types of allergies, visit the American Academy of Allergy, Asthma, and Immunology.
