Goodbye to Allergies? Scientists Discover How to Trick Body's Immune System


Northwestern University researchers have a 'Trojan horse' strategy for treating asthma and allergies. Digital Vision/Laguna Design/Meschaman/Getty
Northwestern University researchers have a 'Trojan horse' strategy for treating asthma and allergies. Digital Vision/Laguna Design/Meschaman/Getty

If you suffer from allergies or asthma, you may be able one day to say goodbye to all those temporary treatments and over-the-counter drugs. Researchers at Northwestern University have developed a system that could end allergies once and for all, by forcing our bodies to recognize harmless objects, like certain foods, or environmental allergens, like pollen, as friendly.

The study was published in April in the Proceedings of the National Academy of Sciences.

The immune system's main job is to repel harmful bacteria and viruses. But sometimes, it works against us, treating certain foods, like eggs or shellfish, like enemies. When that happens, the immune system builds up antibodies to fight the allergens, and we experience inflammation, mucous buildup, itching, sneezing — in short, a good, old-fashioned allergic response.

Medications, like antihistamines, only control allergy symptoms. But researchers have found that if they "smuggle" the allergen into the body, the body's natural defense system will think the substance is harmless.

Here's how they did it. Researchers developed dissolvable nanoparticles out of a U.S. Food and Drug Administration-approved polymer (a chain of molecules) that includes lactic acid and glycolic acid. They filled the polymers with egg protein and injected them into mice that had been pretreated to be allergic to eggs. So, when the mice were re-exposed to eggs, they had an asthma-like allergic response.

But after the mice were injected with the nanoparticles, their immune systems recognized the eggs as harmless, and their bodies didn't react. What's more, the nanoparticles containing the stealth allergens were consumed by a macrophage, or "vacuum-cleaner" cell.

"The vacuum-cleaner cell presents the allergen or antigen to the immune system in a way that says, 'No worries, this belongs here.' The immune system then shuts down its attack on that allergen, and gets reset to normal," Stephen Miller, senior author of the study, said in a press release.

And, there was another, unexpected benefit: The mice's immune systems were actually stronger than before. Researchers found that the nanoparticles turn off the dangerous Th2 T cell that causes the allergy and expand the number of T cells, which calm and regulate the immune system.

These findings could have far-reaching implications for the treatment of all kinds of allergies. "It's a universal treatment. Depending on what allergy you want to eliminate, you can load up the nanoparticle with ragweed pollen or a peanut protein," explained Miller, a research professor of Microbiology-Immunology at Northwestern University's Feinberg School of Medicine.

The team is now focused on doing further tests in mice, and eventually humans.