Not all children with a peanut allergy respond to desensitization.

Berlin scientists have discovered clues as to why some children with a peanut allergy do not respond to immunotherapy or even have allergic reactions. They believe that certain blood markers could help predict in advance how well or poorly a child will respond to the therapy. The study, led by the research team of scientists Young-Ae Lee from the Max Delbrück Center for Molecular Medicine and Kirsten Beyer from the Charité, was published in the journal "Allergy."

For the study, the researchers examined the blood and its immune cells from 38 children. The children were on average seven years old and received oral desensitization for their peanut allergy. The scientists examined, among other things, blood concentrations of allergy antibodies (immunoglobulins) and inflammatory messengers (cytokines) before and after treatment.

"Children who responded well to treatment appeared to have a less reactive immune system even before starting therapy," explained lead author Aleix Arnau-Soler. "We found lower immunoglobulin and cytokine levels in their blood."

These potential biomarkers could be used in the future to determine how well a child responds to treatment and what the associated risks are before desensitization begins. It's also conceivable that the length of treatment and the amounts of peanut allergen administered could be adapted to the immune profile of each patient, Lee said.

The researchers are now planning another study to confirm the results and are working on a prognosis model to tailor desensitization to the child in the future using a simple blood test.

According to scientists, three percent of all children in industrialized countries have a peanut allergy. Oral immunotherapy attempts to slowly accustom the body to the allergen by ingesting it orally. The therapy helps many, but in some, it triggers severe allergic reactions.