IgE-reactive carbohydrate epitopes--classification, cross-reactivity, and clinical impact

Area of Science:

• Allergen immunotherapy
• Glycobiology
• Immunology

Background:

• Glycan-related IgE-reactivity is common in allergens, particularly from plants.
• Glyco-epitopes, or Cross-reactive Carbohydrate Determinants (CCDs), share structural similarities across different protein families.
• CCDs can cause cross-reactivity between diverse sources like pollens and insect venoms.

Purpose of the Study:

• To clarify the role of glyco-epitopes and CCDs in allergic reactions.
• To investigate the potential in vivo significance of glycan-related IgE responses.
• To emphasize careful interpretation of in vitro allergy test results.

Main Methods:

• Review of current literature on glycobiology and allergen cross-reactivity.
• Analysis of studies demonstrating cellular responses to glyco-epitopes.
• Consideration of IgE-reactivity testing towards glycoprotein models like bromelain.

Main Results:

• Glyco-epitopes and CCDs exhibit significant cross-reactivity, sometimes acting as pan-epitopes.
• CCDs are not universally cross-reactive, clustering into groups like plant or fungal CCDs.
• Recent research indicates glyco-epitopes can elicit cellular responses, suggesting potential in vivo relevance.

Conclusions:

• In vitro allergy tests detecting glycan- and CCD-related IgE require careful interpretation due to potential cross-reactivity.
• The clinical significance of CCDs is being re-evaluated, moving beyond solely in vitro findings.
• Understanding the glycome of natural products is crucial for accurate allergy diagnostics.