Epitope analysis of Ara h 2 and Ara h 6: characteristic patterns of IgE‐binding fingerprints among individuals with similar clinical histories. Issue 2 (February 2015)

• Record Type: Journal Article
• Authors: Otsu, K.; Guo, R.; Dreskin, S. C.
• Is Part Of: Clinical & experimental allergy. Volume 45:Issue 2(2015:Feb.)
• Page Start: 471
• Page End: 484
• Publication Date: 2015-02
• Subjects: Allergy -- Periodicals; Immunology -- Periodicals; 616.97
• DOI: 10.1111/cea.12407
• Languages: English
• ISSNs: 0954-7894

Abstract

<abstract abstract-type="main" id="cea12407-abs-0001"> <title>Summary</title> <sec id="cea12407-sec-0001" sec-type="section"> <title>Background</title> <p>Ara h 2 and Ara h 6 are moderately homologous and highly potent peanut allergens.</p> </sec> <sec id="cea12407-sec-0002" sec-type="section"> <title>Objective</title> <p>To identify IgE‐binding linear epitopes of Ara h 6, compare them to those of Ara h 2, and to stratify binding based on clinical histories.</p> </sec> <sec id="cea12407-sec-0003" sec-type="section"> <title>Methods</title> <p>Thirty highly peanut‐allergic subjects were stratified by clinical history. Sera were diluted to contain the same amount of anti‐peanut IgE. IgE binding to overlapping 20‐mer peptides of Ara h 2 and Ara h 6 was assessed using microarrays.</p> </sec> <sec id="cea12407-sec-0004" sec-type="section"> <title>Results</title> <p>Each subject had a unique IgE‐binding fingerprint to peptides; these data were coalesced into epitope binding. IgE from subjects with a history of more severe reactions (<italic>n</italic> = 19) had a smaller frequency of binding events (BEs) for both Ara h 2 (52 BEs of 152 (19X8epitopes) possible BEs and Ara h 6 (13 BEs of 133 (19X7 epitopes) possible BEs) compared to IgE from those with milder histories (<italic>n</italic> = 11) (Ara h 2: 47 BEs of 88 (11X8 epitopes) possible BEs, <italic>P</italic> < 0.01; Ara h 6: 25 BEs of 77 (11X7 epitopes) possible BEs, <italic>P</italic> < 0.001). Using an unsupervised hierarchal cluster analysis, subjects with similar histories tended to cluster. We have tentatively identified a high‐risk pattern of binding to peptides of Ara h 2 and Ara h 6, predominantly in subjects with a history of more severe reactions (OR = 12.6; 95% CI: 2.0–79.5; <italic>P</italic> < 0.01).</p> </sec> <sec id="cea12407-sec-0005" sec-type="section"> <title>Conclusions and Clinical Relevance</title> <p>IgE from patients with more severe clinical histories recognize fewer linear epitopes of Ara h 2 and Ara h 6 than do subjects with milder reactions and bind these epitopes in characteristic patterns. Close examination of IgE binding to epitopes of Ara h 2 and Ara h 6 may have prognostic value.</p> </sec> </abstract>