In a small study, sublingual immunotherapy (SLIT) was effective in desensitizing peanut-allergic toddlers, allowing 74 percent to consume 4,443 milligrams of peanut (about 15 peanuts) without reacting, new research finds.
“What we are seeing is super-promising,” says lead study author Dr. Edwin Kim, an assistant professor of allergy and immunology at the University of North Carolina at Chapel Hill. “We observed significant desensitization in toddlers with peanut allergy,” he told Allergic Living.
Kim suggests that SLIT, which involves allergen extract being given under-the-tongue, could become an early intervention option for young peanut-allergic children.
The study, presented at the 2021 American Academy of Allergy, Asthma & Immunology (AAAAI) Virtual Annual Meeting in late February, enrolled 50 children with peanut allergy between the ages of 1 and 4 years of age. They were divided into two treatment arms with similar demographics and allergy profiles. One group received extract containing 4 mg of peanut protein daily, while the other got placebo. The study was conducted over three years, with 36 patients completing it.
Participants took part in an oral food challenge at the three-year mark. Fourteen of 19 kids in the SLIT group achieved desensitization – they could eat 4,443 mg of peanut without symptoms. That was up from an average of 143 mg at the study start. Children given the placebo could eat a median of 143 mg of peanut, up from 43 mg at the start.
SLIT and ‘Unresponsiveness’
To test whether these desensitized youngsters had achieved “sustained unresponsiveness,” that is, protection from peanut allergen without taking a daily dose, the kids then went off treatment for three months.
At the end of that period, the research team conducted another food challenge. Twelve of the 14 in the SLIT group who passed the desensitization challenge were still able to consume 4,443 mg of peanut without reacting. They achieved “sustained unresponsiveness.” (Two in the placebo group also passed.)
During SLIT treatment, side effects were minor – about 5 percent of doses resulted in symptoms such as an itchy mouth or rash. But none required epinephrine, and in most cases the rash went away on its own without treatment, says Kim.
Over the past decade, several studies have looked at using SLIT to treat peanut allergy in children and adults.
In 2019, Kim and his colleagues published a study on SLIT and 37 children ages one to 11. In it, participants stayed on a daily maintenance dose of 2 mg of peanut protein – about half the dose strength used in the newer study – for five years. The researchers found that 67 percent of children were able to tolerate at least 750 mg of peanut protein in an exit challenge without symptoms. (There are about 300 mg in one peanut kernel.) About 25 percent could tolerate 5,000 mg.
Therapy’s Potential in Young Kids
This new study honed in on younger children since Kim says earlier research suggested that younger children’s immune systems might be more malleable. “Prior studies showed kids 8 years old and older responded to SLIT, but not as well as younger kids,” he says.
Kim notes that with toddlers, there’s always concern about reactions “because they can’t tell us if they don’t feel right. They can’t verbalize a lot of things.” He sees another potential benefit of SLIT is that the risk of side effects appears to be lower than treatments such as oral immunotherapy.
For peanut SLIT to become widely available, larger, multi-center studies are needed. The study was funded by a grant from Food Allergy Research & Education (FARE).
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