Newswise – New research from the University of British Columbia shows a safe way to overcome food allergies for older children and others who can’t risk consuming allergens orally to build up their resistance.

It’s called sublingual immunotherapy (SLIT) and involves placing small amounts of food allergens under the tongue.

One by UBC clinical professor and pediatric allergist Dr. A study conducted by Edmond Chan and his team at the BC Children’s Hospital Research Institute found that SLIT is as safe and effective for older, high-risk children and adolescents as oral immunotherapy for preschoolers.

“Our work confirms the safety and effectiveness of SLIT in older children and adolescents with multiple food allergies and a higher risk of severe reactions,” said Dr. Chan. “These are patients who are typically denied oral immunotherapy because it is considered too risky. Therefore, this may be the best approach for this population.”

Previously published research results by Dr. Chan’s team has shown that oral immunotherapy in preschool age is safe and effective in practice. The protocol calls for a “build-up” period of several months in which patients visit a clinic every two weeks to take a higher dose of an allergen under medical supervision before taking the same daily dose between visits. Once they reach a certain dose – usually around 300 mg of protein – they enter a “maintenance phase” where they take that daily target dose at home. After a year of maintenance dosing, about four out of five patients can pass an oral challenge test in which they can tolerate a much higher dose of 4,000 mg of protein.

However, the build-up phase is risky for older children and those with a history of severe reactions. Dr. Chan’s group has been looking for a safer way to move this vulnerable group of patients into the maintenance phase.

They recruited about 180 such patients between the ages of four and 18, most with multiple food allergies. The SLIT protocol (which went into effect when COVID-19 pandemic restrictions were implemented) required patients to attend virtually monitored appointments three to five times over several months to build up a small dose – in most cases as little as 2 mg of protein , which is absorbed through the membranes under the tongue rather than being swallowed and ingested.

The patients’ caregivers learned how to mix and administer these doses at home, using novel recipes based on products found in the supermarket and developed with the team’s nutritionist. A variety of allergens have been treated including peanuts, other legumes, tree nuts, sesame, other seeds, eggs, cow’s milk, fish, wheat, shrimp and other allergens. Patients took these doses daily for 1-2 years.

“It takes up to twice as long as oral immunotherapy, but we couldn’t have done it any other way because we needed the superior safety of SLIT for these older children, who are considered more severe,” said Dr. Chan.

While most patients had mild symptoms during the build-up phase, none experienced severe reactions during the build-up or maintenance phases. 70 percent of those tested at the end of the protocol were able to tolerate 300 mg of their allergen – a success rate almost as high as that of oral immunotherapy.

The results were encouraging for a therapy that every family can do at home under the guidance of professionals.

“Aside from safety considerations in older children, allergists are often quite burdened by the build-up phase of oral immunotherapy, as a patient may require 11 or more clinic visits. “They just don’t believe they have the capacity to offer that many visits in their office,” said Dr. Chan. “In our clinic we are starting to provide more home treatments as the demand for medical appointments that would allow monitoring far exceeds the supply. We seek to develop a data-driven approach that balances a patient’s level of risk with the appropriate level of monitoring. Our SLIT data suggests that home SLIT setup is safe.”

Ultimately, the study highlights an alternative that allergists should now consider for patients who cannot safely complete oral immunotherapy. The trade-off for greater safety is simply a longer time frame, but with the advantage of keeping clinics free for those who need them most.

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