Cross-reactive carbohydrate determinants (CCD): Mimickers of allergy

Abstract

79 Cross-Reactive Carbohydrate Determinants (CCD): Mimickers of Allergy C. H. Bridts, D. G. Ebo, M. M, Hagendorens, L. S. De Clerck, W. J. Stevens; Immunology-Allergology-Rheumatology, University of Antwerp, Antwerpen, BELGIUM. RATIONALE: To investigate the prevalence of anti-CCD-IgE in healthy controls and patients allergic to pollen, house dust mite (HDM), pets, natural rubber latex (NRL) and hymenoptera venom. To study the contribution of anti-CCD-IgE as a cause of clinically irrelevant IgE for NRL and apple. METHODS: IgE antibodies were quantified by Immuno-CAP. Skin prick tests (SPT) were performed with HAL extracts, except for bromelain (500 [ag/mL, Sigma-Aldrich). Patients were identified as anti-CCD-IgE positive if they had a negative SPT and positive IgE for bromelain. Sera containing IgE against apple or NRL were classified as true-positive or falsepositive according to the presence or absence of an oral allergy syndrome (OAS) or NRL-induced anaphylaxis. RESULTS: No anti-CCD-IgE was found in controls (n=12), patients monosensitized to NRL (rl=19), pets (n=7), HDM (n=28) or birch pollen (n=32). In contrast, anti-CCD-lgE was present in 21% (4/19) of patients with grass pollinosis, 25% (4/20) of patients with combined grass and birch pollinosis, in 4/8 of patients with combined grass, tree and weed pollinosis (p=0.03), and in 14% (4/28) of patients with venom anaphylaxis. Falsepositive NRL individuals had a higher prevalence of anti-CCD-lgE than NRL allergic patients (78% (18/23) versus 0% (0/19), p<0.001). In individuals with a false-positive lgE to apple, the frequency of anti-CCD-IgE was higher than in OAS patients (38% (15/40) versus 11% (3/27), p=0.03). CONCLUSIONS: Sensitization to CCD, caused by grass pollen or hymenoptera venom allergens, can mimic NRL and apple allergy. Patients monosensitized to NRL or birch pollen showed no anti-CCD-IgE. Funding: Danone Institute