title: Skin test evaluation of genetically engineered hypoallergenic derivatives of the major birch pollen allergen, Bet v 1: results obtained with a mix of two recombinant Bet v 1 fragments and recombinant Bet v 1 trimer in a Swedish population before the birch pollen season.
abstract: BACKGROUND
  More than 95% of birch pollen-allergic subjects react with the major birch pollen allergen, Bet v 1, and almost 60% of them are sensitized exclusively to this allergen.
  
  
  OBJECTIVE
  The aim of this study was to compare the in vivo biologic activity of genetically engineered hypoallergenic derivatives of Bet v 1 (an equimolar mixture of 2 recombinant [r] Bet v 1 fragments and of rBet v 1 trimer) with that of rBet v 1 wild-type by skin prick and intradermal testing.
  
  
  METHODS
  Birch pollen-allergic patients who had not received immunotherapy (n = 23), a group of allergic patients without birch pollen allergy (n = 12), and nonatopic persons (n = 8) from northern Europe (Sweden) underwent skin prick and intradermal testing with different concentrations of the recombinant allergens and commercial birch pollen extract before the birch pollen season. Immediate and late-phase reactions were recorded and allergen-specific IgE and IgG subclass responses were determined by CAP radioallergosorbent test and ELISA, respectively.
  
  
  RESULTS
  Atopic persons without birch pollen allergy and nonatopic individuals did not have skin reactions to rBet v 1 wild-type and genetically engineered hypoallergenic derivatives. By intradermal testing, 8 of 23 and 13 of 23 birch pollen-allergic patients did not react with the highest concentration (1 microg/mL) of the rBet v 1 fragment mix and rBet v 1 trimer, respectively, compared with 1 with rBet v 1 wild type. Likewise, the highest concentration (100 microg/mL) of fragment mix or trimer failed to elicit a positive skin prick test in 18 of 23 and 15 of 23 patients in comparison with 0/23 with the monomer. No late reactions were observed.
  
  
  CONCLUSIONS
  The recombinant hypoallergenic birch pollen allergens can probably be used for patient-tailored immunotherapy with a reduced risk to induce anaphylactic reactions.
authors.affiliation: Department of Clinical Immunology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: van Hage-Hamsten
authors.forename: M
authors.initials: M
authors.lastname: Kronqvist
authors.forename: O
authors.initials: O
authors.lastname: Zetterström
authors.forename: E
authors.initials: E
authors.lastname: Johansson
authors.forename: V
authors.initials: V
authors.lastname: Niederberger
authors.forename: S
authors.initials: S
authors.lastname: Vrtala
authors.forename: H
authors.initials: H
authors.lastname: Grönlund
authors.forename: R
authors.initials: R
authors.lastname: Grönneberg
authors.forename: R
authors.initials: R
authors.lastname: Valenta
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant; D001249:Asthma / Q000097:blood / Q000276:immunology*; D003233:Conjunctivitis, Allergic / Q000097:blood / Q000276:immunology*; D005069:Evaluation Studies as Topic; D005260:Female; D005818:Genetic Engineering; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007136:Immunoglobulins / Q000097:blood; D007428:Intradermal Tests; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000276:immunology; D010940:Plant Proteins / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D012621:Seasons; D012882:Skin Tests; D013548:Sweden; D014197:Trees
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D007074:Immunoglobulin G; D007136:Immunoglobulins; D010446:Peptide Fragments; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C061312:Bet v 1 allergen, Betula; D007073:Immunoglobulin E