Identification of IgE-reactive proteins in patients with wheat protein contact dermatitis.
BACKGROUND
Wheat protein and its derivatives can cause protein contact dermatitis (PCD), which mainly occurs in bakers. Few studies have attempted to identify the allergens responsible for wheat PCD.


OBJECTIVE
The aim of this study was to identify allergenic wheat proteins in patients with wheat PCD.


METHODS
Water-soluble and water-insoluble wheat flour proteins were separated by 1- or 2-dimensional gel electrophoresis. IgE-binding proteins were detected by immunoblotting with sera from 3 wheat PCD patients and identified by N-terminal amino acid sequence analysis. The IgE-binding proteins were recombinantly expressed in Escherichia coli and tested against patients' sera.


RESULTS
IgE antibodies from the patients' sera reacted with water-soluble proteins rather than water-insoluble proteins, and the 2-dimensional electrophoresis and immunoblotting produced individual IgE-binding patterns. Analysis of the N-terminal amino acid sequence of the IgE-binding proteins from the 2-dimensional gel led to the identification of three glycoproteins, wheat 27-kDa allergen, peroxidase, and purple acid phosphatase. No specific IgE antibodies to their non-glycosylated recombinant proteins were observed.


CONCLUSIONS
We identified wheat 27-kDa allergen, peroxidase and purple acid phosphatase as candidate allergens for wheat PCD. Our results suggest that glycan moieties in these proteins are involved in IgE binding.
Matsuo
Hiroaki
H
Division of Clinical Pharmacotherapeutics, Graduate School of Biomedical Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan. hmatsuo@hiroshima-u.ac.jp
Uemura
Masako
M
Yorozuya
Miyuki
M
Adachi
Atsuko
A
Morita
Eishin
E
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology / Q000302:isolation & purification*; D000888:Antibodies, Anti-Idiotypic / Q000097:blood / Q000276:immunology; D002352:Carrier Proteins / Q000097:blood / Q000276:immunology; D003296:Cooking; D017449:Dermatitis, Allergic Contact / Q000097:blood / Q000276:immunology*; D009783:Dermatitis, Occupational / Q000097:blood / Q000276:immunology*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D008297:Male; D010940:Plant Proteins / Q000032:analysis / Q000276:immunology*; D014908:Triticum / Q000737:chemistry / Q000276:immunology*
D000485:Allergens; D000888:Antibodies, Anti-Idiotypic; D002352:Carrier Proteins; D010940:Plant Proteins; D007073:Immunoglobulin E