Peanuts are tasty treats but they can also trigger serious allergic reactions in some people. About one in 50 children in the US is allergic to peanuts. And while some experience only mild reactions, it can be life-threatening to others, causing anaphylaxis — an acute hypersensitivity reaction that has to be treated right away.

There’s only one approved allergy treatment but it takes months to kick in, has to be taken for life and doesn’t really stop patients from having allergic reactions. Seeking other alternatives, researchers have now used mRNA (the type of molecule used in the COVID-19 vaccines) to develop a treatment that could even reverse signs of an allergy.

“As far as we can find, mRNA has never been used for an allergic disease,” André Nel, the paper’s co-corresponding author, said in a statement. “We’ve shown that our platform can work to calm peanut allergies, and we believe it may be able to do the same for other allergens, in food and drugs, as well as autoimmune conditions.”

Tackling allergies

In previous studies, the researchers at the University of California, Los Angeles (UCLA) identified a fragment of a peanut protein (the epitope) that alleviated peanut allergies in mice when delivered to the liver via a nanoparticle. This was because of the liver’s antigen-presenting cells that train the immune system to tolerate foreign proteins.

“If you’re lucky enough to choose the correct epitope, there’s an immune mechanism that puts a damper on reactions to all of the other fragments,” said Nel, who the university’s Center for Environmental Implications of Nanotechnology, or CEIN. “That way, you could take care of a whole ensemble of epitopes that play a role in disease.”

For their new study, the researchers encoded mRNA in a way that can tell the cells how to create the peanut allergy epitope – the same way that mRNA vaccines for SARS-CoV-2 encode the spike protein of the virus. They then put the mRNA in the nanoparticle and added a sugar molecule to the surface to help it bind to the liver

The researchers tested the treatment by applying two doses to mice a week apart. For comparison, other groups of mice got either no treatment, the treatment without the sugar molecule or the nanoparticle with mRNA that didn’t code for anything. A week later, they gave the mice a peanut protein extract that could lead to allergies.

The group that got the sugar nanoparticle treatment had the least severe reaction, which suggests that the therapy could prevent the development of a severe peanut allergy, the researchers said. They then did the experiment a second time but gave the allergens before administering the treatment and also found mild symptoms.

Up next, the researchers believe the peanut allergy treatment could be tested in human clinical trials in about three years. But it doesn’t end there. They believe the same system can be used to prevent or treat other allergies and even help people overcome type 1 diabetes – something now being explored by other researchers.

The study was published in the journal ACS Nano.