title: Identification and implication of an allergenic PR-10 protein from walnut in birch pollen associated walnut allergy.
abstract: English walnut (Juglans regia) belongs to the most important allergenic tree nuts. Co-sensitization with birch (Betula verrucosa) pollen has been reported. We aimed to identify a walnut allergen homologous to the major birch pollen allergen Bet v 1.
  
  
  
  A cDNA encoding a Bet v 1-homologous allergen (Jug r 5) in walnut kernels was cloned by RT-PCR. Jug r 5 was expressed in Escherichia coli, purified by column chromatography and characterized by circular dichroism spectroscopy. Specific IgE levels to walnut, Bet v 1, and Jug r 5 in birch pollen allergics (n = 16) with concomitant walnut allergy were measured by ImmunoCAP: 44% of the patients were tested positive to walnut while 94% were reactive to Jug r 5, and 100% to Bet v 1. Jug r 5 and Bet v 1 allergens showed bidirectional IgE cross-reactivity by competitive ELISA and were capable of inducing histamine release from effector cells. Immunoblot competition experiments demonstrated the presence of IgE-reactive Jug r 5 in walnut extract, but at low levels.
  
  
  
  A Bet v 1-like allergen was identified in walnut. Diagnostic use of Jug r 5 will compensate for the low sensitivity of walnut extract for patients with birch pollen associated walnut allergy.
authors.affiliation: VPr1 Research Group Molecular Allergology, Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Wangorsch
authors.affiliation: VPr1 Research Group Molecular Allergology, Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Jamin
authors.affiliation: ThermoFisherScientific, Uppsala, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Lidholm
authors.affiliation: Department of Dermatology, University Hospital Zürich, Zürich, Switzerland.
authors.forename: Nora
authors.initials: N
authors.lastname: Gräni
authors.affiliation: Department of Dermatology, University Hospital Zürich, Zürich, Switzerland.
authors.forename: Claudia
authors.initials: C
authors.lastname: Lang
authors.affiliation: Department of Dermatology, University Hospital Zürich, Zürich, Switzerland.|Center of Dermatology and Allergology, Luzerner Kantonsspital, Luzern, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Ballmer-Weber
authors.affiliation: VPr1 Research Group Molecular Allergology, Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Vieths
authors.affiliation: VPr1 Research Group Molecular Allergology, Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Scheurer
mesh_terms: D000485:Allergens / Q000276:immunology*; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000378:metabolism / Q000494:pharmacology*; D029662:Betula / Q000737:chemistry*; D003429:Cross Reactions; D005260:Female; D006636:Histamine Release; D006801:Humans; D006967:Hypersensitivity; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology; D031324:Juglans / Q000737:chemistry*; D009754:Nuts / Q000276:immunology; D010940:Plant Proteins / Q000276:immunology / Q000378:metabolism*; D011058:Pollen / Q000276:immunology*
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C000624464:PR-10 protein, walnut birch pollen; D010940:Plant Proteins; C061312:Bet v 1 allergen, Betula; D007073:Immunoglobulin E
keywords: Bet v 1 like; Juglans regia; Jug r 5; PR-10; Walnut allergy