Two Different Composite Markers Predict Severity and Threshold Dose in Peanut Allergy

Abstract

Background: Safe and cost-effective biological surrogate markers to evaluate the severity and threshold dose of peanut allergy (PA) reactions during an oral food challenge (OFC) are lacking.

Objective: To evaluate biological markers associated with the severity and threshold dose of an allergic reaction during an OFC in a population of children with PA.

Methods: Demographic and biological parameters of children with peanut OFC and basophil activation test (BAT) results were collected. Patients were stratified into 2 severity groups (mild-to-moderate and severe) and 2 cumulative threshold dose groups: low (LCTG) ≤100 mg crushed peanut and high >100 mg.

Results: Among the 68 children included, there was a 96% concordance between the OFC and BAT result for the diagnosis of PA. Of the 56 children with a positive OFC and BAT to peanut (median age: 8.8 years), the severity of an allergic reaction and the cumulative threshold dose were not correlated (P = .24). Higher Ara h 2-specific IgE and FcεRI-positive control values were both associated with severe reactions to peanut. Combining these 2 markers led to a 92% sensitivity (84%-97%) and an 82% specificity (71%-89%) for severe reactions in all subjects. For children in the LCTG, a 4-variable composite marker, including age, normalized basophil sensitivity (EC₅₀), and FcεRI- and fMLP-positive control values, resulted in a 97% sensitivity (89%-99%) and 61% specificity (49%-71%).

Conclusion: Distinct composite markers including BAT allergen-specific and non-allergen-specific parameters appear to be associated with severity and cumulative threshold dose in children with PA.

Keywords: Basophil activation test; FcεRI-positive control; Oral food challenge; Peanut allergy.