A potentially fatal peanut allergy was switched off when scientists tricked the immune system to no longer treat nut proteins as a threat to the body, researchers from Northwestern Medicine reported in the Journal of Immunology. The authors explained that they attached peanut proteins onto white blood cells and placed them back in the patient’s body. They believe their method could eventually be used for multiple allergies.
The authors wrote:
“We think we’ve found a way to safely and rapidly turn off the allergic
response to food allergies.”
This approach had been previously used in autoimmune diseases, but never before to create tolerance in the immune system of patients with allergies.
Co-authors, Paul Bryce, PhD. and Stephen Miller, PhD. explained that their approach has a second advantage – it increases the number of regulatory T cells; immune cells that are vital for accepting the peanut proteins as normal. The result is a more balanced immune system.
“T cells come in different ‘flavors’. This method turns off the dangerous Th2 T cell that causes the allergy and expands the good, calming regulatory T cells. We are supposed to be able to eat peanuts. We’ve restored this tolerance to the immune system.”
Peanuts can cause anaphylaxis in some people – life-threatening allergic reactions. The National Institutes of Health informs that there are from 15,000 to 30,000 cases of anaphylaxis caused by eating certain foods in the USA annually, and between 100 and 200 related deaths. The authors wrote that there is currently no safe treatment to protect sufferers form a severe allergic reaction to food.
When an individual with a peanut allergy eats a peanut, its proteins get into the bloodstream through the intestine, and trigger a full-body immune response. The patient’s airways contract, blood pressure drops considerably, they can go into shock, lose consciousness, go into coma, and even die.
In this study they used a mouse model that mimics anaphylactic reactions to peanuts. The scientists attached peanut proteins onto leukocytes and infused them back into the mice. Leukocytes are types of white blood cells. After doing this twice they fed the mice peanut extract. The mice’s immune systems recognized the peanut proteins as safe and did not have a life-threatening reaction to them.
“Their immune system saw the peanut protein as perfectly normal because it was already presented on the white blood cells. Without the treatment, these animals would have gone into anaphylactic shock.”
The authors believe they could eventually attach more than one protein to the leukocyte cell, effectively treating several allergies in one go.
They then did the same with an egg protein, which could trigger an asthma-type attack when the protein is inhaled. They attached the egg protein to the leukocytes and infused them back into the mice. The mice were then exposed to the egg protein which would have triggered an asthma attack – this time their lungs did not become inflamed.
Stephen Miller said:
“This is an exciting new way in which we can regulate specific allergic diseases and may eventually be used in a clinical setting for patients.”
Miller had previously used this approach to stop the progress of type 1 diabetes and MS (multiple sclerosis), both autoimmune diseases. There is currently an ongoing Phase I/IIa clinical trial with MS patients using this approach, Miller explained.
For allergic airway and autoimmune diseases, Miller and team are also working with microparticles, instead of leukocytes to induce tolerance, because microparticles can be more easily standardized for manufacturing.
Written by Christian Nordqvist