Feeding increasing amounts of an allergenic food to raise the reaction threshold may not work for all people with food allergies, research indicates.
A research team, including an epidemiologist from the Translational Research Center for Medical Innovation, made the surprising finding after looking at patients affected by an allergy outbreak that began in Japan in 2004. This spate of cases saw people develop dangerous wheat allergies after using a facial soap that contains a type of wheat protein known as Glupearl 19S. The outbreak prompted itching, eyelid swelling, nasal discharge, and other symptoms in more than 2,000 people across a period of more than 10 years.
Yuma Fukutomi, from the Sagamihara National Hospital’s Clinical Research Center for Allergy and Rheumatology, who led the research, says the impetus for the study came from the observation that some of the people affected by the soap can now eat as much wheat as they want, while others continue to experience reactions after just a bite of panko or ramen.
The researchers examined patients who visited Sagamihara National Hospital, a leading site for allergy treatment in Japan. Most of these people had stopped using the soap and eliminated wheat from their diets before slowly reintroducing the food staple. Of these, they identified 29 people who had given up wheat for more than three months, and been trying to consume wheat again for at least two years.
Typically, says Fukutomi, identifying increases in ‘blocking’ antibody IgG4 in the blood is a sign of tolerance to a food allergen. “The patients in this group who had become tolerant to wheat did not show increased IgG4, but the patients with poor disease prognosis showed increases in IgG4,” he explains. “As such, evidence that oral immunotherapies are effective against childhood food allergies should not be applied directly to adult food allergies.”
His work suggests that high IgG4 levels in people with poor allergy prognosis may be the result of sustained low-level inflammation and this type of response might apply to those who develop allergies in later life or those triggered by events that occur outside the gut.
Fukutomi hopes his team’s report will alert other allergy specialists to the complexities of allergic responses in adults. “The finding was quite unexpected,” he says, explaining that it’s probably not restricted to the fallout from the soap incident, and that more research is required.
Fukutomi, Y. et al. Allergen-specific IgG4 over time: Observation among adults with hydrolyzed wheat protein allergy. Allergy 74, 1584–1587 (2019).| article
About the Researcher
Yuma Fukutomi, Chief of the Department of Diagnostic and Therapeutic Research Clinical Research Center for Allergy and Rheumatology