چکیده (انگلیسی):

Background: In Japan, hydrolyzed wheat proteins (HWP) have been reported to cause wheat-dependent
exercise-induced anaphylaxis (WDEIA) by transcutaneous sensitization using HWP-containing soap. Patients
develop allergic reactions not only with soap use, but also with exercise after the intake of wheat protein (WP).
ω5-Gliadin and HMW-glutenin were identified as major allergens in conventional WP-WDEIA patients. However,
the allergens in HWP-WDEIA have yet to be elucidated.
Methods: Sera were obtained from 22 patients with HWP-sensitized WDEIA. The allergenic activities of HWP
and six recombinant wheat gluten proteins, including αβ-, γ-, ω1,2- and ω5-gliadin and low- and high molecular
weight (HMW)-glutenins, were characterized by immunoblot analysis and histamine releasing test. IgE-binding
epitopes were identified using arrays of overlapping peptides synthesized on SPOTs membrane.
Results: Immunoblot analysis showed that IgE antibodies (Abs) from HWP-WDEIA bound to αβ-, γ- and
ω1,2-gliadin. Recombinant γ-gliadin induced significant histamine release from basophils in eight of 11 patients
with HWP-WDEIA. An IgE-binding epitope “QPQQPFPQ” was identified within the primary sequence of γ-
gliadin, and the deamidated peptide containing the “PEEPFP” sequence bound with IgE Abs more strongly
compared to the native epitope-peptide. The epitope-peptide inhibited IgE-binding to HWP, indicating that the
specific IgE to HWP cross-reacts with γ-gliadin.
Conclusions: HWP-WDEIA patients could be sensitized to HWP containing a PEEPFP sequence, and
WDEIA symptoms after WP ingestion could partly be induced by γ-gliadin. These findings could be useful to
help develop tools for diagnosis and desensitization therapy for HWP-WDEIA.