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Background: Flour is still one of the most common causes of occupational asthma worldwide. Thus far, little is known about the relevant allergens causing baker's asthma. Therefore the reliability of current diagnostic procedures is insufficient. Only few of the suspected causative wheat allergens have been hitherto characterized on the molecular level., Objective: The aim was to identify and characterize unknown wheat allergens related to baker's asthma to improve the reliability of diagnostic procedures., Methods: A wheat pJuFo cDNA phage display library was created and screened for IgE binding to wheat proteins with pooled sera from patients with baker's asthma. After identifying an alphabeta-gliadin, the frequency of sensitization was investigated by means of ELISA screening of 153 bakers' sera with the recombinant alphabeta-gliadin. Furthermore, the allergenicity of native total gliadin (alphabeta, gamma, omega) was analyzed by means of ImmunoCAP., Results: One cDNA clone was identified as an alphabeta-gliadin. Serum IgE antibodies to the recombinant allergen were found in 12% of bakers with occupational asthma. Of the asthmatic bakers, 33% showed sensitization to native total gliadin; 4% of them had negative results on routine IgE testing with wheat extract., Conclusions: Gliadins represent a newly discovered family of inhalable allergens in baker's asthma. This finding demonstrates that water-insoluble proteins might also represent causative allergens.

The incidence of sensibilization against extracts of moulds produced by VEB SSW Dresden was investigated by intracutaneous tests in 354 persons (controls and patients - adults and children - with bronchial asthma and allergic rhinitis). Even in the nonallergic controls the tests were positive in 20-30%. Patients with asthma and rhinitis were significantly more often positive than controls with Mucor, Cladosporium and mixed-mould. There was no difference between the groups with Aspergillus and Penicillium. Testing with extract of mixed-mould is not effective. Positive results with the individual moulds were not excluded although the test with mixed-mould was negative. There was no essential difference in the incidence of sensibilization between adults and children with bronchial asthma using mould extracts of VEB SSW Dresden.