Cross-Reactive Carbohydrate Determinants (CCDs) Interference with Component Resolved Diagnosis on NOVEOS™*, ImmunoCAP® and IMMULITE® 2000.

Abstract

Allergen specific IgE (sIgE) can bind CCD structures on plant and insect glycoproteins as well as peptide epitopes. These carbohydrate structures can display structural homology across many allergen groups leading to extensive cross-reactivity, obscure in vitro diagnostic results, and debatable clinical relevance. With the introduction of Component Resolved Diagnosis (CRD), non-glycosylated components can be utilized to prevent the detection of anti-CCD IgE and may improve clinical relevance. The aim of this study is to confirm anti-CCD IgE will not be detected on non-glycosylated components on NOVEOS, ImmunoCAP, and IMMULITE 2000. A panel of CCD-positive samples was selected based on their reactivity to several recombinant components. Samples were tested before and after inhibition with a commercially-available CCD inhibitor on NOVEOS, ImmunoCAP, and IMMULITE 2000. ImmunoCAP IgE binding was reduced by samples pre-incubated with a CCD inhibitor while NOVEOS and IMMULITE 2000 resulted in minimal reduction. The reduction of IgE binding to a non-glycosylated recombinant component from samples with a CCD inhibitor on ImmunoCAP suggests trace amount of CCD are still present in the test. This confirms other studies that have indicated the cellulose used as an allergen carrier on ImmunoCAP may elevate specific IgE result. NOVEOS, a microparticle-based chemistry, and IMMULITE 2000, bead-based technology, resulted in minimal IgE reduction with and without CCD inhibitor.