Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=190213
Story Retrieval Date: 5/23/2013 12:01:26 PM CST
Courtesy of Stephen Miller
A possible way to prevent the inflammatory immune reaction that results from peanut allergies has been reported by researchers at Northwestern University’s Feinberg School of Medicine in the current issue of the Journal of Immunology.
The lead researchers said it is the first time their particular method for creating immune tolerance has been applied toward allergic diseases.
“When you think about everything you eat, you’re introducing these food allergens into your body,” said Paul Bryce, study co-author and assistant professor of medicine. “The intestinal tract is unique in being able to educate our immune system not to respond to those, and one way is through generating regulatory T cells.”
T cells are a type of white blood cell that help deter the immune system from attacking proteins in our food.
When someone with a peanut allergy is exposed to peanut extract, they can experience anaphylaxis, a potentially fatal allergic reaction that can involve a drop in blood pressure or swelling of the throat. More than 3 million Americans are allergic to peanuts or tree nuts, according to the National Institute of Allergy and Infectious Diseases.
As part of the study, Feinberg researchers attached peanut proteins onto blood cells and re-infused them into laboratory mice. Increasing the number of T cells in the subjects’ blood, researchers attached nut proteins onto white blood cells and infused them into the mice’s bloodstreams.They were not able to predict how many years of study are needed before human trials could begin, but they agreed it won’t be soon.
Scientists looked at factors such as body temperature and anaphylactic response in mice. Stephen Miller, a professor of immunology, is the paper’s other senior author, and graduate students Charles B. Smarr and Chia-Lin Hsu also authored the study.
“We still see the mice get swelling around the eyes and mouth, respiratory problems … everything you’d think about with a child who experiences an anaphylactic event,” Bryce said.
Dr. Mary Tobin, director of allergy at Rush University Medical Center, who was not involved in the study, said that right now the only sure treatment for people with food allergies is avoidance.
“Now, to be able to inhibit the immune system or change the messaging at a basic level is really key, because then you can turn off these aberrant responses to peanuts or shellfish, which are the most common allergens,” she said.
The research borrows its methodology from Miller’s previous research in autoimmune diseases such as multiple sclerosis. It began a year and a half ago and was funded by the Food Allergy Initiative, a nonprofit organization founded in 1998, and the National Institutes of Health.
In the second stage of the study, researchers gave the immunized mice a peanut extract and observed no allergic reaction in them — evidence, Miller and Bryce said, that the animals’ immune systems were not trying to combat the foreign protein.
“This is very pleasing to us that the therapy not only works on the autoimmune disease but also works to target this other subset of cells that are central to regulating immune disease,” Miller said.
Tobin said the presence of food allergies and the awareness of anaphylaxis has surfaced in the public consciousness within the past decade, and emergency rooms see more cases of allergy-induced illness than before.
“These families live in a huge amount of fear that a kind person will unwittingly expose their child to a peanut and the child will die,” she said, noting that children also deal with social pressure to eat any and all foods.
Meghann Talkington, a registered dietician who was not involved in the study, said there are several unanswered questions. She would want to know how safe the treatment would be if it were administered in humans, whether it took a pill form or an injection and whether it would be easier for people simply to abstain from peanuts. But she said the researchers’ hypothesis would be a great benefit.
“The research is important to allow people to have more food options,” she said. “Depending on how bad their allergy is, they might not be able to touch the nut versus being able to directly eat them, so the research might make things easier and more convenient for them.”
Julie Campbell, president of the Illinois Food Allergy Education Association, based in Northfield, has a child, now 17, who had an allergic reaction to a peanut butter sandwich as was an infant.
“Because my child couldn’t articulate anything, I didn’t know what was going on,” she said. Beyond the ostensible tells — itchy eyes and a runny nose — she couldn’t discern the severity of the situation.
“Anything that would help eliminate or reduce the severity of an allergic reaction would certainly be welcome to the food allergic community,” she said.
Campbell would want to know whether the study’s observation could manifest in lifelong protection for people with peanut allergies.
Bryce said researchers cannot conclude from the data whether individuals with peanut allergies would be able to eat the food regularly in the long-term or whether it were a matter of being able to protect against accidental ingestion.
“That’s our big picture concept: You could almost personalize based on the individual’s allergic profile.”
Tobin said there are no good answers when it comes to peanut allergies.
“The potential of being able to modulate the immune system by increasing the immune system’s own protection response would be huge,” she said. “Any kid with a food allergy would much rather hear that we have a chance to protect them.”