title: Anaphylactic versus mild reactions to hazelnut and apple in a birch-endemic area: different sensitization profiles?.
abstract: BACKGROUND
  Hazelnut and apple are common causes of food allergy in Europe. In northern Europe, symptoms are usually mild and associated with cross-reactivity to the birch pollen allergen, Bet v 1. In the Mediterranean area, symptoms are more frequently severe and associated with sensitization to lipid transfer protein (LTP). This study compared patients with anaphylactic versus mild reactions to hazelnut and apple in The Netherlands, a birch-endemic area, with respect to sensitization to Bet v 1-homologues (i.e. PR10-proteins) and LTP.
  
  
  METHODS
  Twenty-one patients fulfilling the criteria for anaphylaxis and 21 with only mild symptoms (oral allergy) to hazelnut and/or apple were recruited. Specific immunoglobulin E to birch pollen, apple, hazelnut and PR10-proteins (rBet v 1, rPru p 1, rMal d 1 and rCor a 1) and recombinant LTP (rPru p 3 and rCor a 8) was measured by ImmunoCAP.
  
  
  RESULTS
  Both mild and anaphylactic apple-allergic patients were sensitized to PR10-proteins, whereas only 1/7 of the mild and none of the anaphylactic apple-allergic patients was sensitized to LTP. In contrast, anaphylactic hazelnut-allergic patients displayed no such clear sensitization pattern: some were sensitized to both PR10-proteins and hazelnut LTP (1/9), and others to only LTP (2/9) or to only PR10-proteins (4/9) or to neither PR10-proteins nor LTP (2/9).
  
  
  CONCLUSIONS
  This study shows that in a birch-endemic area, the sensitization profile to PR10-proteins and LTP in anaphylactic patients may differ between different plant foods. In this patient group, anaphylaxis to hazelnut can be LTP-associated, whereas anaphylaxis to apple is not.
authors.affiliation: Department of Dermatology and Allergology, University Medical Center Utrecht, Utrecht, The Netherlands. t.t.m.le-2@umcutrecht.nl
authors.forename: T M
authors.initials: TM
authors.lastname: Le
authors.forename: E
authors.initials: E
authors.lastname: van Hoffen
authors.forename: A F M
authors.initials: AF
authors.lastname: Lebens
authors.forename: C A F M
authors.initials: CA
authors.lastname: Bruijnzeel-Koomen
authors.forename: A C
authors.initials: AC
authors.lastname: Knulst
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000707:Anaphylaxis / Q000276:immunology*; D052179:Antigens, Plant / Q000276:immunology; D029662:Betula / Q000276:immunology*; D002352:Carrier Proteins / Q000276:immunology; D031211:Corylus / Q000276:immunology*; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D008297:Male; D027845:Malus / Q000276:immunology*; D008875:Middle Aged; D010940:Plant Proteins / Q000276:immunology; D012882:Skin Tests; D055815:Young Adult
chemical_list: D052179:Antigens, Plant; D002352:Carrier Proteins; D010940:Plant Proteins; C030363:lipid transfer protein; C061312:Bet v 1 allergen, Betula