New research out of Australia holds great promise. A study team announced in December, 2010 that they had discovered fragments of peanut protein that may be the key component to a peanut vaccine that could be given by injection.

Allergic Living’s Lisa Ferlaino spoke with Dr. Robyn O’Hehir, the team’s leader and a professor of allergy and immunology at Monash University in Australia, about the discovery and what it means.

Why the focus on immunotherapy as a treatment for peanut allergy?

“Allergen immunotherapy is the only treatment that can actually change the natural course of allergic diseases. We know from the aero-allergens such as house dust mites and grass pollens, and even from bee and wasp venom, that allergy shots make a big difference in people’s lives. That’s what we’re striving for.

We also know that peanut allergy is becoming more common worldwide, and that people find traces of peanut in unexpected foods. That’s one of the reasons avoidance isn’t really sufficient.”

Peanuts have long been viewed as too risky for immunotherapy, too likely to provoke anaphylaxis. How do you address that?

“By studying the white blood cells of patients with peanut allergy, we’ve been able to narrow down the core epitopes – the critical fragments of peanut protein that drive the allergic response in people with peanut allergy – and we’ve identified ones that are too small to cause anaphylaxis. They won’t bind to IgE [allergy antibodies], but they’re big enough to kickstart the immune system to develop tolerance.”

Are these fragments parts of peanut’s infamous Ara h 1 and Ara h 2 proteins?

“Yes. We’ve identified the critical peptides [protein fragments] in Ara h 2, the major peanut allergen. That’s the one most associated with anaphylaxis. Ara h 1 is also important, and we’re well on the way to identifying the critical peptides in it, too.”

There are a few peanut therapies in the works. Is your research unique?

“There’s a lot of research in animal models [using mice], but our research looks at human white blood cells. That’s important, because peanut allergy is not a natural condition for mice.”

Next Page: More questions on the vaccine

Peanut

• Tennis player Serena Williams
• NHL player Tom Poti, defenceman for the Washington Capitals
• Singer Alex Kapranos, Franz Ferdinand
• Freestyle aerials champion Steve Omischl

Tree Nut

• Singer Clay Aiken
• NHL player Tom Poti

An anaphylactic reaction includes more than one of the body’s systems, such as the respiratory tract, gastrointestinal tract, the skin and cardiovascular symptom. Symptoms of an allergic reaction include tingling in the mouth, swelling of the tongue and throat, itchy skin or hives, difficulty breathing, abdominal cramping and vomiting. In a severe anaphylactic reaction, a person may experience a drop of blood pressure, loss of consciousness and even cardiac arrest and death.

One of the issues in managing peanut allergy is that symptoms can vary. A person may have had minor symptoms, only to suffer anaphylaxis on a subsequent exposure.

Because peanut allergy reactions can be severe, it is important that a person with this allergy carry an epinephrine auto-injector (EpiPen or Twinject) with them at all times. Peanut allergy is often considered a lifelong allergy, but research has shown up to 20 per cent of children may outgrow it by the time they reach school-age.*

*Source: 2010 FA primer. JACI

Prevalence

In the United States, the rate of peanut allergy in children increased by 3.5 times from 1997 to 2008, to a rate of 1.4 per cent. In Canada, it is estimated that 1.68 per cent of children and 0.71 per cent of adults have peanut allergy.

More on Peanut Allergy Statistics

Next Page: Not a Nut!

Since she had an anaphylactic reaction to a peanut butter cracker at the age of 2, Isabella has been avoiding peanut. But that all changed when her mother, Kathy, saw a report on “Good Morning America” last summer. It was about a team of researchers at Duke University in North Carolina who are trying to desensitize children with allergies to egg and peanut.

The Uknises had seen many doctors who told them there was nothing they could do; Isabella would have to avoid peanut for life. But the doctor and nurse couple always thought desensitization should, in theory, work. They called the university, and before long Isabella was accepted into the study under Dr. Wesley Burks.

Burks and his team at Duke first examined egg allergy and desensitization in a pilot study with seven participants. Over a two-year study period, and working in tiny, sequential increases of egg exposure, four of the children built up enough tolerance to eat two scrambled eggs without a reaction. The others were able to eat just under that amount.

The peanut study, which began three years ago, has 25 children enrolled at various stages. Eight have finished the first phase. After 18 months of being “on peanut,” seven of those eight were able to eat 15 peanuts over the course of an hour. They are now on a higher maintenance dose and will stay on that for more testing.

Isabella began the study last August. The nurses at Duke start by feeding her a minuscule amount of peanut powder, the equivalent of 1/3000th of a peanut, and slowly increased the dose over the course of one day, carefully monitoring her for reactions. The goal was to eat a cumulative 50 mg of peanut powder, the equivalent of 1⁄6th of a peanut.

“She didn’t do as well as we had hoped,” says her mother. At one point Isabella got a belly ache, then her nose started running and eventually, she broke out in hives, ending the day. All told, Isabella ate 25 mg of peanut. “I was really scared,” says Kathy, “I’d seen her go into anaphylaxis before.” The life-threatening potential of allergic reactions hits home for this family. In fact, the night before Isabella anaphylaxed after eating the peanut butter cracker, her father, a transplant surgeon, had done a procurement on a 21-year-old who had died of an allergic reaction.

But at the clinic, when Isabella felt symptoms the nurses treated them with Benadryl, or waited for them to subside before giving her another dose. Their knowledge, and the attention they gave to Isabella, put Kathy at ease. According to Burks, two participants weren’t able to tolerate the buildup phase, and were dropped from the study. But Isabella’s results were good enough to keep going.

After determining each child’s individual tolerance over a day, Burks and his team send them home on a maintenance dose of peanut, which they eat every day for two weeks. Then they return to the research unit for a higher dose, and are watched a few hours to make sure they’re not reacting. The kids being tested go about their regular day but, of course, take all the normal precautions, such as having an EpiPen handy. If a child has a reaction of any significance while taking the dose at home, he or she goes into the research clinic the next day and takes their next dose under the watchful eye of the clinic’s nurses.

The goal of the study is twofold. “We’re trying to desensitize them,” Burks says. “That means that if they’re on the treatment and had an accidental exposure, they would not have symptoms.” But Burks wants to go beyond desensitization, and hopes to make previously allergic people tolerant, even after they’re finished with the treatment. “We will essentially have made [the allergy] go away.”

The allergist hopes to have published results from the peanut study by mid-2007, but the early indications show that desensitization is possible. He acknowledges that proving the ‘tolerating’ part will take a little longer. But a new study, with different doses and lengths of treatment, has already begun.

Burks sees a treatment evolving in the next three to five years. He hopes that at that point, allergists could administer this “oral immunotherapy” to their patients in their offices. Although yet to be studied, Burks believes the treatment would work in adults as well as kids, and for food allergens other than peanut and egg.

Naturally, there is great interest and demand for this type of treatment. Burks has a long waiting list of local parents who want their children enrolled in the studies, in the hope that one day they will be desensitized. For the Uknises and Isabella, that once unreachable goal seems within grasp. Now it’s a matter of wait-and-see: will Isabella be one of the lucky ones?

Excerpted from the Spring 2007 issue of Allergic Living magazine.
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About half of the 50 to 60 dogs that Perry trains in a year are now for people with peanut or other allergies (including tree nut and egg), with 10 already in homes across the United States. “There are a lot of people who really need them,” she says.

The dogs are mainly young (1- to 2-year-old) rescues from shelters, and Perry looks for good working breeds, such as poodles and Labrador retrievers. Perry and a colleague, Leslie Staven,  spend six months preparing the dogs, then work with owners for two weeks on handling, commands and “reading” the dog’s responses, which include sitting firmly by the contaminated object and touching a container with the nose when given the “show me” command.

Karen Jones* of Tampa, Florida, attests to the dogs’ effectiveness. Billy, her 9-year-old son, has a peanut detector dog that accompanies him everywhere from Spanish class to Disney World.

Upon entering a classroom one day, Remy, the black lab, put her nose on top of a box of craft supplies, indicating peanut was present. “I said, ‘show me better,’” recounts Jones. “I swear, she took the lid off the box, took something out with her teeth, and shook it at me.”

The dogs don’t come cheap, at $9,995 US, which includes training, accommodation at the ranch during owner sessions, and follow-up. But for Jones, at least, knowing there’s a super-sensitive snout protecting Billy is priceless. “That dog has literally saved his life,” she says.

* name changed by request.
For more info, see: www.peanutdog.com