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Inhibition of I g E binding to cross‐reactive carbohydrate determinants enhances diagnostic selectivity
Author(s) -
Holzweber F.,
Svehla E.,
Fellner W.,
Dalik T.,
Stubler S.,
Hemmer W.,
Altmann F.
Publication year - 2013
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/all.12229
Subject(s) - immunoglobulin e , allergen , allergy , immunology , medicine , chemistry , pharmacology , antibody
Background Allergy diagnosis by determination of allergen‐specific I g E is complicated by clinically irrelevant I g E , of which the most prominent example is I g E against cross‐reactive carbohydrate determinants ( CCD s) that occur on allergens from plants and insects. Therefore, CCD s cause numerous false‐positive results. Inhibition of CCD s has been proposed as a remedy, but has not yet found its way into the routine diagnostic laboratory. We sought to provide a simple and affordable procedure to overcome the CCD problem. Methods Serum samples from allergic patients were analysed for allergen‐specific I g E s by different commercial tests (from M ediwiss, P hadia and S iemens) with and without a semisynthetic CCD blocker with minimized potential for nonspecific interactions that was prepared from purified bromelain glycopeptides and human serum albumin. Results Twenty two per cent of about 6000 serum samples reacted with CCD reporter proteins. The incidence of anti‐ CCD I g E reached 35% in the teenage group. In patients with anti‐ CCD I g E , application of the CCD blocker led to a clear reduction in read‐out values, often below the threshold level. A much better correlation between laboratory results and anamnesis and skin tests was achieved in many cases. The CCD blocker did not affect test results where CCD s were not involved. Conclusion Eliminating the effect of I g E s directed against CCD s by inhibition leads to a significant reduction in false‐positive in vitro test results without lowering sensitivity towards relevant sensitizations. Application of the CCD blocker may be worthwhile wherever natural allergen extracts or components are used.