They estimate that 4–6 percent of all children in the United States are affected by food allergies, though other reports reveal that percentage to be much higher.
Of all food allergies, those to peanuts are the most common.
Food allergies do not yet have a cure, and allergic reactions can prove fatal. In fact, the only way to "prevent" allergies is to stay away from the allergen.
A new study, however, offers hope for people with peanut allergies, as a vaccine that has been 2 decades in the making has just been proven successful in mice.
The research — which has now been published in the Journal of Allergy and Clinical Immunology — was carried out by scientists at the University of Michigan in Ann Arbor. They were led by Jessica O'Konek, a researcher at the university's Food Allergy Center.
Stopping peanut allergies in mice
O'Konek and team explain that food allergies are caused by a faulty immune reaction, wherein the body overproduces antibodies called Immunoglobulin E (IgE).
This occurs as a result of a skewed immune response from immune cells called T helper 2 (Th2). In the new research, the scientists hypothesized that rerouting these Th2 cells might help to regulate the allergic immune response.
To test this hypothesis, O'Konek and colleagues sensitized mice to peanut proteins so that their immune system produced IgE antibodies and their Th2 cells behaved in the same way that they would in an allergic reaction.
When exposed to peanuts, the rodents thusly sensitized developed the same allergic symptoms, such as itchy skin and obstructed breathing, as humans.
The researchers then administered the rodents one dose of the nasal vaccine per month for 3 months, and they measured their allergic response 2 weeks after the final dose.
The vaccine successfully protected the rodents from exposure to peanuts, with tests showing decreased activity of the Th2 cells, as well as decreased IgE antibodies.
"By redirecting the immune responses," explains O'Konek, "our vaccine not only suppresses the response but prevents the activation of cells that would initiate allergic reactions."
The researchers still need to assess precisely how long this protection lasts, but they are hopeful that the benefits will be long-lasting.
'Potential therapy of allergies in humans'
Once the researchers figure out whether or not they can prolong the benefits of the vaccine and fully grasp the mechanisms through which this vaccine suppresses allergies, the findings can be used to start a clinical trial for humans.
"Right now, the only FDA [Food and Drug Administration]-approved way to address food allergy is to avoid the food or suppress allergic reactions after they have already started," O'Konek says.
"Our goal is to use immunotherapy to change the immune system's response by developing a therapeutic vaccine for food allergies."
"Food allergy has exploded in prevalence and incidence, but we still know so little about it because there hasn't been that much research in the field," says senior study author Dr. James Baker, the director of the Mary H. Weiser Food Allergy Center at the University of Michigan.
"This research is also teaching us more about how food allergies develop and the science behind what needs to change in the immune system to treat them," he adds.
"We're changing the way the immune cells respond upon exposure to allergens [...] Importantly, we can do this after [the] allergy is established, which provides for potential therapy of allergies in humans."