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Background: Food allergy to wheat and maize is an increasing factor of deterioration of life quality, especially childhood and can, in rare cases, even induce anaphylaxis. Although omega-5 gliadin from wheat and maize lipid transfer protein have been characterized as major cereal allergens on the molecular level, the list of food allergens is far to be complete. Methods: To identify the IgE-binding repertoires of wheat and maize we screened respective cDNA libraries displayed on phage surface with sera from patients with a confirmed food allergy. The study included six patients with a positive double-blind, placebo-controlled food challenge (DBPCFC) to wheat, nine patients with a positive DBPCFC to maize, and six patients with anaphylactic reactions after ingestion of wheat. Results: The enriched sequences encoding IgE-binding proteins showed heterogeneous repertoires for both, wheat and maize. The selected wheat repertoire yielded 12, the maize repertoire 11 open reading frames. Among these we identified allergens belonging to already characterized allergens families, such as gliadin, profilin and beta-expansin. Besides, we found novel proteins with high cross-reactive potential, such as thioredoxins, as well as sequences that had so far not been related to cereal allergy at all. The IgE-binding capacity of some selected proteins was evaluated in vitro and cross-reactivity was demonstrated by competition ELISA. Conclusion: With regard to the heterogeneity of the characterized sequences as well as to the biochemical nature of the new allergens detected we conclude that wheat and maize-related food allergy is more complex than so far anticipated. [ABSTRACT FROM AUTHOR]

The article provides information on the discovery of new allergens in fruits and vegetables. It has been noted that allergens in fruits and vegetables have been particularly studied in recent year. One of the reason is the clinical importance of cross-reactions between vegetable foods and pollens. However, the latest observations concerned allergens which are specific to fruits and closely related to the clinical expression of allergy.

The article focuses on the diagnostic procedures problems of cross-reactions of allergens. It has been indicated that cross-reactivity can elicit positive in vitro or in vivo allergy tests. It is an in vitro phenomenon caused by immunoglobulin E antibodies directed against epitopes expressed in molecular structures.

The aim of this study was to assess the ability of nedocromil sodium (NS) to prevent the immediate asthmatic reaction and the increase in the serum level of heat stable neutrophil chemotactic activity (HS-NCA) induced by antigen inhalation. In a double-blind, cross-over study. 13 atopic subjects affected with seasonal asthma underwent a bronchial provocation test with a preselected dose of grass pollen allergen (enough to cause a decrease of >20% in FEV1:FEV1 PD20) after pre-treatment with 4 mg NS or placebo. Serum samples were withdrawn from 11 subjects for HS-NCA determination. After NS administration the decrease in FEV1 was significantly less than after placebo administration at all time points after challenge (2 min P = 0 0004; 7 min. P=0 0005; 17 min P = 0 0002 and 27 min P=0 0005). The percentage increase in HS-NCA was significantly higher after placebo than after NS inhalation, both 10 (P=0 0048) and 20 (P=0 0068) min after challenge. Our study confirms previous investigations, showing that NS inhibits the immediate asthmatic response to allergen inhalation in atopic. asthmatic subjects and moreover it shows that this drug prevents in vivo the increase of the serum HS-NCA. This last finding has not been previously reported. [ABSTRACT FROM AUTHOR]