Identification and characterization of the major allergens of buckwheat.

Abstract

BACKGROUND:

Buckwheat (BW) has been recognized as a common food allergen in Korea, Japan, and other countries. Until now, serologic findings of BW food-allergic patients and its major allergenic components have not been clarified. In this study, we analyzed the serologic findings of BW food allergy and characterized its major allergenic components.

METHODS:

Nineteen BW-allergic subjects with symptoms after BW ingestion and 15 asymptomatic control subjects with positive skin prick test to BW were recruited. BW-specific IgE was measured with the Pharmacia CAP kit. Allergenic components of BW were analyzed by IgE immunoblotting, periodate oxidation, two-dimensonal PAGE, and sequencing of N-terminal amino acids.

RESULTS:

From the BW-allergic patients and asymptomatic controls, the sensitivity (100%), specificity (53%), and negative (100%) and positive predictive values (73%) of Pharmacia CAP specific IgE for diagnosis were estimated. The prevalence of IgE binding to 24-kDa (pI 8.3), 16-kDa (pI 5.6), and 9-kDa (pI 5.0/ 6.0) allergens was higher than 50% in BW-allergic and asymptomatic subjects. However, the specific IgE to split 19-kDa (pI 6.5/7.0) allergens were more specifically found in BW-allergic patients than in asymptomatic subjects (78% vs 7%). N-terminal amino-acid sequences of 19-kDa and 16-kDa allergens showed moderate and weak homology to the 19-kDa globulin protein of rice and alpha-amylase/trypsin inhibitor of millet, respectively. The N-terminus of the 9-kDa isoallergens were not different from each other and were identified as the reported trypsin inhibitors of BW. Attenuation of the IgE binding to the 9-kDa allergen was found with periodate oxidation.

CONCLUSIONS:

The allergens of 24, 19, 16, and 9 kDa are strong candidates to be major allergens, and the 19-kDa allergen was relatively specific for BW-allergic patients. Moreover, measurement of BW-specific IgE and the features of immunoblotting should be very useful tools in the diagnosis of BW allergy.

• Authors: J W Park, D B Kang, C W Kim, S H koh, H Y Yum, K E Kim, C S Hong, K Y Lee
• Journal: Allergy (Allergy) Vol. 55 Issue 11 Pg. 1035-41 (Nov 2000) ISSN: 0105-4538 [Print] Denmark
• PMID: 11097313 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Allergens
• Immunoglobulin E

Topics

• Adolescent
• Adult
• Allergens (analysis, chemistry)
• Amino Acid Sequence
• Double-Blind Method
• Female
• Food Hypersensitivity (etiology)
• Humans
• Immunoblotting
• Immunoglobulin E (blood)
• Male
• Molecular Sequence Data
• Molecular Weight
• Polygonaceae (immunology)