Molecular and immunological characterization of wheat allergens responsible for Baker's asthma

Abstract

<b>Introduction:</b> Airborne flour allergens cause the most common form of occupational Asthma (OA), namely baker9s asthma. Major wheat allergens have not been described yet. Commercial allergy tests base on native wheat extracts and are limited in quality. For the improvement and standardization of the diagnostics it is important to identify further relevant allergens. The aim of our study was identifying so far unknown flour allergens. <b>Methods:</b> With a wheat cDNA phage display library (<i>Triticum aestivum</i><i>L.</i>) we screened sera from bakers with OA for IgE binding structures and identified different clones. After sequencing and identification of the proteins, an expression and purification procedure of recombinant proteins followed. We screened sera of 151 bakers with occupational asthma with an Enzyme Linked Immunosorbent Assay (ELISA) and compared the results with those from ImmunoCAP f4 (wheat flour; Thermo Fisher Scientific, Freiburg, Germany). <b>Results:</b> Among the enriched cDNA stock from the wheat phage display library we identified 5 new flouer allergens, namely 3 different transcription factors, and 2 so far unknown proteins. Screening 151 bakers9 sera showed sensitizations in 3 to 13 %, depending on the recombinant allergen. 21 sera, which did not react to the commercial ImmunoCAP-test, reacted with at least one of the recombinant allergens. <b>Conclusions:</b> We were able to identify 5 new wheat allergens, 3 transcription factors and 2 unknown proteins, acting as minor allergens in baker9s asthma. Since major allergens have not been described for baker9s asthma, a pattern of multiple allergens have to be tested to verify the diagnosis. Recombinant allergens can be used to expand the test panel.