Predicting reactivity threshold in children with anaphylaxis to peanut.

Area of Science:

• Allergy and Immunology
• Pediatric Allergy
• Clinical Immunology

Background:

• Peanut allergy management often requires dietary restrictions, ideally guided by individual reactivity thresholds determined via oral food challenges (OFC).
• Severe peanut allergy in children can pose risks, often precluding OFC due to potential systemic reactions.

Purpose of the Study:

• To identify clinical and immunological factors associated with peanut allergy reactivity thresholds in children experiencing anaphylaxis.
• To investigate if these factors correlate with the severity of allergic reactions during OFC.

Main Methods:

• A double-blinded placebo-controlled food challenge (DBPCFC) was conducted on 96 children (aged 5-15) with a history of severe peanut reactions or sensitization.
• Pre-challenge assessments included interviews, skin prick tests (SPT), lung function tests, serological IgE/IgG/IgG4 levels, basophil activation tests (BAT), and conjunctival allergen provocation tests (CAPT).

Main Results:

• All 96 children experienced anaphylaxis during the DBPCFC.
• Basophil activation, peanut SPT, and the peanut-specific IgE/total IgE ratio were significantly linked to reactivity thresholds and the lowest observed adverse event levels (LOAEL).
• Basophil activation effectively predicted very low peanut thresholds (<3 mg), with a 75.8% cut-off yielding a 93.5% negative predictive value.

Conclusions:

• In children with peanut anaphylaxis, basophil activation, peanut SPT, and peanut-specific IgE/total IgE ratio correlate with reactivity thresholds and LOAEL.
• These immunological and clinical markers were not associated with the severity of allergic reactions during OFC.