Identification and molecular characterization of allergenic nsLTP from durum wheat (Triticum turgidum).

BACKGROUND: Common wheat (Triticum aestivum) and durum wheat (Triticum turgidum) are both involved in baker's asthma (BA) and food allergy (FA) including WDEIA. However, allergens in durum wheat have not been described, and the over-expression of T. turgidum nsLTPs is considered to increase resistance to phytopathogens.

OBJECTIVE: To identify and assess the allergenicity of nsLTP from T. turgidum.

METHODS: Recombinant T. turgidum nsLTP Tri tu 14 was generated and tested for structural integrity (CD-spectroscopy) and purity (SDS-PAGE). Thirty-two wheat allergic patients were enrolled: 20 Spanish patients (BA) with positive bronchial challenge to wheat flour, and 12 Italian patients (wheat FA/WDEIA) with positive DBPCFC/OFC to pasta. IgE values to wheat, Tri tu 14, Tri a 14 (T. aestivum) and Pru p 3 (P. persica) were determined by ImmunoCAP testing. Allergenic potency (in vitro mediator release) and IgE cross-reactivity were investigated.

RESULTS: Tri tu 14 was found to share 49% and 52% amino acid identity with Tri a 14 and Pru p 3, respectively. Among 25 Tri a 14 CAP positive sera, 23 (92%) were reactive to wheat extract, 22 (88%) to Tri tu 14 and 20 (80%) to Pru p 3. The correlation between Tri a 14 and Tri tu 14 specific IgE levels was r=0.97 (BA) and r=0.93 (FA/WDEIA), respectively. FA/WDEIA patients showed higher specific IgE values to Tri tu 14 and Pru p 3 than BA patients. Tri tu 14 displayed allergenic activity by mediator release from effector cells and IgE cross-reactivity with Pru p 3. The degree of IgE cross-reactivity between the two wheat nsLTPs varied between individual patients.

CONCLUSIONS & CLINICAL RELEVANCE: Sensitization to Tri tu 14 likely appears to be more important in wheat FA/WDEIA than in baker's asthma. Over-expression of Tri tu 14 in wheat would represent a risk for patients with nsLTP-mediated food allergy. This article is protected by copyright. All rights reserved.