Gradual Exposure to Peanut Protein May Help Develop Tolerance to Allergy

Giving children with known allergies tiny amounts of peanut protein can actually help the immune system build tolerance over time, according to research presented at the American Academy of Asthma, Allergy & Immunology meeting last month. However, doctors caution that this method is not something that can be attempted at home; peanut allergies can be life−threatening and doses in the study were carefully controlled.

The...children showed increased tolerance to the protein, even if they still could not eat peanuts by the end of the study.

Investigators from Duke University Medical Center and Arkansas Children's Hospital gave peanut−allergic children a small dose of peanut protein or placebo (the first quantity of peanut protein was the equivalent of about 1/1000 of a peanut). Doses were gradually increased over a period of 10 months, until they reached amounts equal to about 15 peanuts per day. Then children continued a daily maintenance therapy as needed.

Thirty−three of the kids were still on maintenance therapy two and a half years later, and continued to take the peanut protein successfully. Four of these nine children were able to discontinue therapy completely. The remaining children showed increased tolerance to the protein, even if they still could not eat peanuts by the end of the study.

The team wondered how the immune system was changing in response to the treatment, so they tracked Immunoglobulin E (IgE), an antibody made by the body in response to perceived allergens. They found that by the end of treatment, the children's IgE levels had all dropped, but in those who could ultimately eat a handful of peanuts, the IgE levels were almost nonexistent. This change implies that the body was no longer treating the peanut protein like a foreign invader requiring attack.

The study's lead author Wesley Burks says that what's exciting about the research is that it shows that the "threshold" for setting off an allergic reaction had been changed over the course of treatment. As a result, if a child who has undergone treatment accidentally ingests a food containing peanuts, an allergic reaction may not necessarily result. He points out that this benefit itself is well worth doing the research: "if you do that alone, you give the family comfort."

Burks adds that he hopes the research will ultimately lead to a more effective medical treatment for food allergies than currently exists. As in the case of peanuts, food allergies can be life−threatening and cause significant stress to the affected individual and to his or her family. Burks and his team are already at work on a follow−up study to further investigate oral allergy therapy.