A generally applicable solution to this problem has not yet been presented. When positive results are based solely on the reaction of CCDs with anti-CCD IgE, results must be rated as false-positive. Further studies on horseradish peroxidase should be carried out to define the role of the glycan side chains in its allergenic activity.Ĭross-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. IgE to cross-reacting carbohydrate determinants are common among the allergic population and the binding to skin test negative allergenic extracts further confirms their poor biological activity. Horseradish peroxidase was the only glycoprotein capable of exerting a positive skin test in 21% of the subjects with IgE to cross-reacting carbohydrate determinants, 80% of them having IgE to the HRP molecule. A higher correlation was found mainly with plant-derived allergenic extracts, whereas a lower one was recorded with mites and fungi. Almost all the allergenic extracts recorded negative in the skin test gave a positive IgE test in vitro.
Prevalence further increased in subsets with multiple pollen sensitization (71%), and with a previous pollen immunotherapy course (46%), whereas minor differences were found in gender and age distribution. Prevalence varied when subsets of non-allergic (5%), non-pollen-allergic (10%), and pollen-allergic (31%) subjects were considered. To find out whether a glycoprotein is capable of triggering an allergic reaction, 1,076 subjects were also skin tested with several purified molecules bearing carbohydrate side chains differing in number, composition and complexity.Īn overall prevalence of 23% of positive IgE to cross-reacting carbohydrate determinants was recorded. Data were analysed on the basis of demographical and allergological parameters. In previous studies we showed how the presence of IgE to bromelain could be a useful and simple marker of the presence of IgE to carbohydrate epitopes.Ī survey of 1,831 subjects with a suspected allergic respiratory disease has been carried out by detecting IgE to bromelain. IgE to cross-reacting carbohydrate determinants has already been described by several authors, but their function and distribution are still a matter of debate.
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