Allergies are substances which trigger excessive histamine or cytokine release into the blood. It's these substances which cause most allergic reactions like rashes, gastrointestinal issues, etc. Research has shown that a similar histamine release response is what causes many asthma symptoms, explaining why allergies and asthma are often interrelated. A new study has found that the same amplifier of asthma also amplifies food allergy responses.
The study, published in The Journal of Clinical Investigation, follows on a 2012 study involving histamine release in asthma. That previous study found a protein called histamine-releasing factor (HRF) played a large role in the inflammation associated with asthma. The new study finds that the same protein amplifies food allergy response as well.
The HRF protein binds to immunoglobulin E (IgE) and acts in synergy to activate mast cells, enhancing inflammation.
The researchers engineered mice to become allergic to egg protein and then treated them with an oral HRF inhibitor. The inhibitor was designed to keep HRF from interacting with IgE, thus lowering allergic responses. Mice who were treated with the inhibitor showed fewer or no signs of inflammation or allergic response after being exposed to egg proteins. Mice who were not given the inhibitor showed the expected response to egg proteins. In vitro studies verified the mice test results.
"The fact that orally-administered HRF inhibitors can prevent development of food allergy in a mouse strongly hints that we could create similar medicine to treat humans with food allergy," says Tomoaki Ando, PhD., the study's first author and now an assistant professor at Juntendo University in Tokyo.
Immunologists call the IgE responsive HRF "HRF-reactive IgE" and it's being found to be more common in children with egg allergies. The research team suspects that it is also a factor in other food allergies, including peanut allergies and others.
Clinical trials for an anti-allergy procedure called rush oral immunotherapy (OIT) have provided secondhand proof that this HRF-reactive IgE plays a significant role in egg allergy immunotherapy efficacy. The researchers involved in this latest test of an HRF inhibitor believe that adding it to the protocols for immunotherapy treatments like OIT could significantly improve outcomes.
"I hope to see protection for patients who go to a restaurant and don't know what ingredients are in the food," says Kawakami, a professor in LJI's Division of Cellular Biology. "In the future, they might take an oral inhibitor as a preventive measure. Our biggest concern for these individuals remains anaphylaxis--it's potentially lethal."