Published online: October 7, 2020
Peanut allergy is one of the most frequent causes of anaphylaxis in children with food allergies. Oral food challenge remains the gold standard to evaluate threshold dose and severity of peanut allergy. However, oral food challenge is resource-intensive, time-consuming, and carries a risk of anaphylaxis, justifying investigations for biological surrogates for diagnosis and to evaluate threshold dose and severity.
In this issue of The Journal of Allergy and Clinical Immunology: In Practice, Cottel and al. report the relevance of allergen-specific and non-allergen-specific basophil activation test (BAT) parameters to determine severity and threshold dose of peanut allergic reactions in children. Demographic and biologic parameters of children with peanut oral food challenge and basophil activation test results were collected. Patients were stratified into 2 severity groups (mild-to-moderate and severe) and 2 cumulative reactive threshold dose groups: low <100mg crushed peanut; and high >100mg.
Among the 68 children included, there was a 96% concordance between the oral food challenge and basophil activation test result for the diagnosis of peanut allergy. Of the 56 children with a positive oral food challenge and basophil activation test to peanut (median age: 8.8 years), severity of allergic reaction and cumulative reactive threshold dose were not correlated (p=0.24). Higher Ara h 2-specific IgE and FcεRI-positive control on basophil activation test values were both associated with severe reactions to peanut. Combining these two markers led to 92% sensitivity [84%–97%] and 82% specificity [71%–89%] for severe reactions in all subjects. For children in the low cumulative reactive threshold dose group, a 4-variable composite marker including age, normalized basophil sensitivity (EC50), and FcεRI- and fMLP-positive control values, resulted in 97% sensitivity [89%–99%] and 61% specificity [49%–71%].
Finally, distinct composite markers including basophil activation test allergen-specific and non-allergen-specific parameters were associated with severity and cumulative reactive threshold dose in children with peanut allergy. Introduction of these multivariable models in routine practice could avoid oral food challenge in some children with peanut allergy.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.