Peanut allergies may be reversible

“Peanuts! Peanuts! Get your peanuts!” Baseball. Summertime. American bleachers.

For a growing number of children and parents in high-income countries, this legume-induced map of association skips over images of America’s pastime to haunting scenes of anaphylactic shock. Peanut allergies, which describe the immune system’s response to a protein found in peanuts, can cut off breathing and lead to a drop in blood pressure, creating a potentially life-threatening situation. Those afflicted with the most serious form of this condition are forced to live a life of hyper-vigilance, double-checking ingredient lists and menus, reminding friends to avoid eating peanuts around them and avoiding food functions without clear peanut-free zones. However, thanks to a recent trial published in The Lancet, this hyper-vigilant necessity may soon change.

Researchers led by Andrew Clark, a pediatric allergist at Cambridge University Hospitals NHS Foundation Trust in the United Kingdom, found that oral immunotheraphy (OIT), a medical treatment in which allergic children are given small doses of peanut protein everyday, may reverse adverse reactions to peanuts. Clark’s team fed 49 children, ages 7 to 16, meals with small amounts of peanut flour. The dose was increased from 2mg to 800mg, about the equivalent of 5 peanuts, over six months. Sixty-two percent of the participants could tolerate 1400mg of peanut protein, the equivalent of about ten peanuts, at the end of the trial. Eighty-four percent could tolerate a daily dose of 800mg.

The study included a control group of 46 children as well. These participants, also allergic to peanuts, completely avoided legumes during the six-month period. At the end of the trial, no one from the control group could tolerate ingestion of peanut protein. However, after these same children followed the OIT regime in the second phase of the trial, 54% could tolerate 1400mg and 91% could tolerate 800mg.

Studies on peanut have been taboo for the last few decades. This medical liminality is largely due to a study conducted in the 1990s in which researchers tried to inject an antigen into the skin of allergic patients. Many participants of this study experienced severe side effects, and one participant died due to a dosage error. However, there is a clear need for medical research into peanut allergies. No preventative measures other than complete legume avoidance are currently available, and this option is hardly sufficient, as nearly half of all children with peanut allergies eat legumes accidentally over the course of a year.

Thus, Clark’s study, in which only one child had to use an EpiPen (to placate an adverse reaction) and no one went to the hospital, may provide a gateway to further research.  Clark seems to think he has unlocked a viable treatment: He hopes to offer OIT as a “named patient program,” which allows doctors to use unapproved therapies on patients if no other treatment options are available. However, other experts in the field are sobering this approach, pointing to problems with Clark’s study.

Kirsten Beyer, a pediatrician at the Charité University Medicine Berlin, is not satisfied with Clark’s trial and would have liked him to use a placebo treatment in his control group. Gideon Lack, a pediatric allergist at King’s College London questions the long-term effects of OIT treatment. Clark says that his OIT patients could tolerate small gaps, but those who stopped OIT treatment altogether saw their allergies return in nine months. Hugh Sampson, an allergy researcher at Mount Sinai Hospital in New York, notes that Clark does not address optimal dose quantity, chemical agents that may make therapy safer or long-term consequences of OIT.

Though peanut allergies are far from being cured, this study is clearly making movements in the right direction. If you or someone you know has a peanut allergy, continue avoiding legumes, but keep an eye on the medical research. You may be able to return to peanut-baseball word associations sooner than you think.