Ara h 2 and Ara 6 are the best predictors of severe peanut allergy: a double-blind placebo-controlled study.

Abstract

BACKGROUND:

Component-resolved diagnostics offers a modern tool in peanut allergy, but studies applying consistently double-blind placebo-controlled challenges are lacking. We aimed to optimize diagnostics for moderate-to-severe peanut allergy in a birch-endemic region and to create an oral-peanut challenge with its allergen activity characterized.

METHODS:

We performed double-blind placebo-controlled peanut challenges for a referred sample of 6- to 18-year-olds with peanut sensitization or a high suspicion of peanut allergy, including anaphylaxis. We measured specific IgE (sIgE) to Ara h 1, 2, 3, 6, 8, and 9. Testing of allergen activity of the challenge products was by IgE microarray inhibition.

RESULTS:

Of the 102 patients, 69 were challenge positive: 25 (36%) had severe, 36 (52%) moderate, and 8 (12%) mild symptoms; 38 (37%) received adrenalin. SIgE to Ara h 6 AUC 0.98 (95%CI, 0.96-1.00) was the best marker of moderate-to-severe allergy. When sIgE to Ara h 2 and Ara h 6 was measured together, all (100%) severe reactions at low doses were successfully diagnosable. SIgE to Ara h 8 had no diagnostic value, AUC 0.42 (95%CI, 0.30-0.52). Both nonroasted and roasted peanut inhibited 100% of IgE binding to Ara h 1, 2, 3, and 6. Nonroasted peanut inhibited 87% of IgE binding to Ara h 8, roasted inhibited 30%. The products lacked Ara h 9 activity.

CONCLUSION:

Co-sensitization to Ara h 2 and Ara h 6 was associated with severe reactions distinguishing severe allergy from mild symptoms. SIgE to Ara h 8 added no diagnostic value. Component-resolved diagnostics reduce the need for oral challenges in peanut allergy.

• Authors: A K Kukkonen, A S Pelkonen, S Mäkinen-Kiljunen, H Voutilainen, M J Mäkelä
• Journal: Allergy (Allergy) Vol. 70 Issue 10 Pg. 1239-45 (Oct 2015) ISSN: 1398-9995 [Electronic] Denmark
• PMID: 26095653 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Chemical References

• 2S Albumins, Plant
• Allergens
• Antigens, Plant
• Ara h 6 allergen, Arachis hypogaea
• Ara h II protein, Arachis hypogaea
• Glycoproteins
• Immunoglobulin E

Topics

• 2S Albumins, Plant (immunology)
• Adolescent
• Allergens (immunology)
• Antibody Specificity (immunology)
• Antigens, Plant (immunology)
• Arachis (adverse effects)
• Child
• Female
• Glycoproteins (immunology)
• Humans
• Immunization
• Immunoglobulin E (immunology)
• Male
• Peanut Hypersensitivity (diagnosis, immunology)
• ROC Curve
• Risk Factors
• Severity of Illness Index
• Skin Tests