Inhibition of cross-reactive carbohydrate determinants (CCDs) enhances the accuracy of in vitro allergy diagnosis

Cross-reactive carbohydrate determinants (CCDs) as they occur on natural allergens from plants and insects influence the measurement of antigen-specific IgE-antibodies in the context of in vitro allergy diagnosis. When positive

Elimination of CCD-specific IgE antibodies by means of a synthetic CCD-blocker drastically reduced the number of false-positive in vitro test results without compromising the sensitivity for relevant IgE interactions. Thus, the herein described CCD-blocker constitutes a valuable tool for increasing the test specificity of routine in vitro allergy diagnosis.

More than 20% of all patients were tested positive for IgE-anti-CCD antibodies and hence against a multitude of similarly glycosylated allergen extracts in a strip-based multiallergen test. Incubation of these positive sera with the CCD-blocker led to significant reductions of read-out values and in many cases to negative test results. The inhibitory efficiency was highest for the allergen strip test and for the component array. Results remained positive for relevant allergens for which a true sensitization had been indicated by skin tests or other means. The CCD-blocker did not alter the read-outs for unglycosylated allergens or - with CCD-negative sera - for all allergens.