Ana o 3 sIgE testing increases the accuracy of cashew allergy diagnosis using a two-step model.

Abstract

BACKGROUND:

Measurement of cashew-specific IgE (sIgE) is often used to confirm sensitization but does not reliably diagnose clinical allergy. Ana o 3 is the dominant cashew allergen detected in 75-100% of patients with cashew allergy but not currently used in clinical practice.

OBJECTIVES:

To determine if component-resolved diagnostics using specific IgE to the 2 S albumin from cashew, Ana o 3, improves the accuracy of diagnosing cashew allergy, thereby circumventing the need for an oral food challenge (OFC) in some patients.

METHODS:

A population-based sample of 5276 children was recruited at age 1 year and followed up at age 6 years. Children with positive cashew skin prick test at age 6 underwent an OFC to clarify allergy status. Forty-seven children (mean age 5.02 ± 0.2) (33 cashew-allergic and 14 cashew-tolerant) had cashew sIgE and Ana o 3 sIgE quantified by ImmunoCAP System FEIA.

RESULTS:

A cutoff of >0.32 kUA/L for Ana o 3 sIgE provided 95% specificity and 90% sensitivity and correctly identified 90% of clinical cashew allergy. At the same specificity, the sensitivity for cashew sIgE (>8.5 kUA/L) was only 26%. Sequential measurement of cashew sIgE followed by Ana o 3 sIgE diagnosed 90% of children with cashew allergy without the need for an OFC.

CONCLUSION:

Ana o 3 sIgE testing provides higher diagnostic accuracy than cashew sIgE. Sequential measurement of cashew sIgE followed by Ana o 3 removed the need for a food challenge from 66% down to 12.8% (5-fold) of children compared with cashew sIgE testing alone.

• Authors: Thanh D Dang, Rachel Peters, Melanie R Neeland, Tim Brettig, Hayden Green, Vicki McWilliam, Mimi L K Tang, Shyamali Dharmage, Anne-Louise Ponsonby, Jennifer Koplin, Kirsten P Perrett, HealthNuts Investigators
• Journal: Pediatric allergy and immunology : official publication of the European Society of Pediatric Allergy and Immunology (Pediatr Allergy Immunol) Vol. 33 Issue 1 Pg. e13705 (01 2022) ISSN: 1399-3038 [Electronic] England
• PMID: 34821421 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2021 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Chemical References

• Allergens
• Immunoglobulin E

Topics

• Allergens
• Anacardium
• Child
• Child, Preschool
• Humans
• Immunoglobulin E
• Infant
• Nut Hypersensitivity (diagnosis)
• Skin Tests