Rice-induced anaphylaxis: IgE-mediated allergy against a 56-kDa glycoprotein

Area of Science:

• Food allergy research
• Immunology
• Proteomics

Background:

• Rice (Oryza sativa) is a global staple with limited reported immediate hypersensitivity reactions.
• Studies on rice allergy, particularly in Asia, have focused on rhinitis, asthma, and atopic dermatitis.
• This case study investigates a German patient experiencing anaphylaxis after rice consumption.

Observation:

• Prick-to-prick tests confirmed IgE-mediated allergy to both raw and cooked rice.
• Specific IgE levels against rice (f9) were elevated, and basophil activation tests (BAT) showed positive responses to rice extracts.
• Immunoblotting identified four IgE-reactive proteins in rice, with molecular weights of 49, 52, 56, and 98 kDa.

Findings:

• A 56-kDa glycoprotein allergen was identified, showing IgE binding partially independent of cross-reactive carbohydrate determinants (CCD).
• IgE binding to other identified rice proteins (49, 52, 98 kDa) was significantly inhibited by CCD, suggesting cross-reactivity.
• The 56-kDa glycoprotein appears to be a primary allergen responsible for anaphylaxis in this patient.

Implications:

• Identifies specific rice allergens, particularly a 56-kDa glycoprotein, implicated in anaphylaxis.
• Highlights the importance of considering rice as a potential allergen in patients with unexplained anaphylaxis.
• Contributes to understanding the molecular basis of food allergies and developing diagnostic strategies.