The aim was to identify and characterize unknown wheat allergens related to baker's asthma to improve the reliability of diagnostic procedures.
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 αβ-gliadin, the frequency of sensitization was investigated by means of ELISA screening of 153 bakers' sera with the recombinant αβ-gliadin. Furthermore, the allergenicity of native total gliadin (αβ, γ, ω) was analyzed by means of ImmunoCAP.
One cDNA clone was identified as an αβ-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.
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.