IgE binding to linear epitopes of Ara h 2 in peanut allergic preschool children undergoing oral Immunotherapy

Pediatr Allergy Immunol. 2019 Dec;30(8):817-823. doi: 10.1111/pai.13117. Epub 2019 Oct 21.

Abstract

Background: For patients with peanut allergy, there are currently no methods to predict who will develop sustained unresponsiveness (SU) after oral immunotherapy (OIT).

Objective: Assess IgE binding to peanut (PN), Ara h 2, and specific linear epitopes of Ara h 2 as predictors of the important clinical parameters: eliciting dose threshold and attainment of SU following OIT.

Methods: Samples and clinical data were collected from children undergoing OIT. PN- and Ara h 2-sIgE were quantified by ImmunoCAP® . IgE binding to linear peptides of Ara h 2 and Ara h 6 was measured with peptide microarrays.

Results: Values of PN-sIgE correlated with eliciting dose (P = .001) and with a higher likelihood of achieving SU (P < .0001), but these relationships were lost at higher values for PN-sIgE (≥14 kIU for eliciting dose and ≥35 kIU/L for SU). In subjects with PN-sIgE ≥ 14 kIU/L, binding of IgE to epitopes 5 and 6 of Ara h 2 was associated with a lower eliciting dose at baseline challenge (P < .001; Pc < .02). In subjects with PN-sIgE ≥ 35 kIU/L, a combined model of IgE binding to epitopes 1, 5 and 6 with PN-sIgE was highly predictive of attainment of SU (AUC of 0.86; P = .0067).

Conclusion: In young patients with peanut allergy, measurement of PN-sIgE and IgE binding to specific linear epitopes of Ara h 2 in baseline samples may allow stratification of patients regarding sensitivity to challenge and outcome of OIT.

Keywords: IgE; allergens; food allergy; immunotherapy; oral immunotherapy; peanut allergy; tolerance induction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2S Albumins, Plant / immunology
  • 2S Albumins, Plant / metabolism*
  • Administration, Oral
  • Allergens / immunology*
  • Animals
  • Antigens, Plant / immunology
  • Antigens, Plant / metabolism*
  • Arachis / immunology
  • Child, Preschool
  • Desensitization, Immunologic / methods*
  • Epitopes
  • Female
  • Humans
  • Immunoglobulin E / metabolism*
  • Male
  • Peanut Hypersensitivity / diagnosis
  • Peanut Hypersensitivity / therapy*
  • Peptide Mapping / methods*
  • Protein Binding

Substances

  • 2S Albumins, Plant
  • Allergens
  • Antigens, Plant
  • Ara h 2 allergen, Arachis hypogaea
  • Epitopes
  • Immunoglobulin E