Carbohydrates as food allergens.

Area of Science:

• Immunology
• Allergology
• Biochemistry

Background:

• Carbohydrate epitopes were previously considered weak allergens, causing non-specific cross-reactivity in IgE testing.
• Rising food allergy prevalence coincides with reports of anaphylaxis triggered by carbohydrate epitopes.
• Two distinct carbohydrate-induced allergic reactions have recently been identified with unique characteristics and geographical distributions.

Purpose of the Study:

• To review current literature on carbohydrate-induced food allergies.
• To evaluate two emerging groups of carbohydrate allergies: galactose-α-1,3-galactose (α-Gal) and galacto-oligosaccharides.
• To discuss how these findings challenge previous understandings of carbohydrate allergenicity.

Main Methods:

• Literature review and synthesis of existing research on carbohydrate-induced allergies.
• Analysis of case reports and epidemiological data for α-Gal and galacto-oligosaccharide allergies.
• Comparison of the characteristics and triggers of these two distinct carbohydrate allergies.

Main Results:

• Anaphylaxis linked to the α-Gal epitope, found in red meat and cetuximab, is associated with tick sensitization in US and European populations.
• Anaphylaxis triggered by galacto-oligosaccharides in milk formula has been reported in Asian populations, notably Singapore.
• The galacto-oligosaccharide allergy represents a unique case of anaphylaxis induced by a pure carbohydrate allergen.

Conclusions:

• Carbohydrate epitopes can induce significant allergic reactions, including anaphylaxis, challenging prior assumptions.
• α-Gal and galacto-oligosaccharide allergies represent distinct clinical entities with specific sensitizers and geographical patterns.
• Further research is needed to understand the mechanisms and management of these emerging carbohydrate-induced food allergies.