title: Identification of enolases and aldolases as important fish allergens in cod, salmon and tuna: component resolved diagnosis using parvalbumin and the new allergens.
abstract: BACKGROUND
  The majority of fish-allergic patients are sensitized to parvalbumin, known to be the cause of important IgE cross-reactivity among fish species. Little is known about the importance of fish allergens other than parvalbumin.
  
  
  OBJECTIVE
  The aim of this study was to characterize hitherto undefined fish allergens in three commonly consumed fish species, cod, salmon and tuna, and to evaluate their importance for in vitro IgE-diagnosis in addition to parvalbumin and fish gelatin.
  
  
  METHODS
  Sixty-two patients were diagnosed by clinical history, skin prick tests and specific IgE to fish extracts. Two new fish allergens from cod, salmon and tuna were identified by microsequencing. These proteins were characterized by immunoblot, ELISA and mediator release assay. Purified parvalbumin, enolase, aldolase and fish gelatin were used for quantification of specific IgE in ELISA.
  
  
  RESULTS
  Parvalbumin and two other allergens of 50 and 40 kDa were detected in IgE-immunoblots of cod, salmon and tuna extracts by most patient sera. The 50 and 40 kDa proteins were identified as beta-enolase and fructose-bisphosphate aldolase A respectively. Both purified enzymes showed allergenic activity in the mediator release assay. Indeed, 72.6% of the patients were sensitized to parvalbumin, 20% of these had specific IgE to salmon parvalbumin only. IgE to enolases were found in 62.9% (0.5-95.0 kUA /L), to aldolases in 50.0% (0.4-26.0 kUA /L) and to fish gelatin in 19.3% (0.4-20.0 kUA /L) of the patients. Inter-species cross-reactivity, even though limited, was found for enolases and aldolases by IgE-inhibition ELISA.
  
  
  CONCLUSIONS
  Fish enolase and aldolase have been identified as important new fish allergens. In fish allergy diagnosis, IgE to enolase and aldolase are especially relevant when IgE to parvalbumin are absent.
authors.affiliation: Laboratory of Immunogenetics and Allergology, CRP-Santé, L-1526 Luxembourg, Luxembourg. annette.kuehn@crp-sante.lu
authors.forename: A
authors.initials: A
authors.lastname: Kuehn
authors.forename: C
authors.initials: C
authors.lastname: Hilger
authors.forename: C
authors.initials: C
authors.lastname: Lehners-Weber
authors.forename: F
authors.initials: F
authors.lastname: Codreanu-Morel
authors.forename: M
authors.initials: M
authors.lastname: Morisset
authors.forename: C
authors.initials: C
authors.lastname: Metz-Favre
authors.forename: G
authors.initials: G
authors.lastname: Pauli
authors.forename: F
authors.initials: F
authors.lastname: de Blay
authors.forename: D
authors.initials: D
authors.lastname: Revets
authors.forename: C P
authors.initials: CP
authors.lastname: Muller
authors.forename: L
authors.initials: L
authors.lastname: Vogel
authors.forename: S
authors.initials: S
authors.lastname: Vieths
authors.forename: F
authors.initials: F
authors.lastname: Hentges
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions / Q000276:immunology; D005260:Female; D005396:Fish Products / Q000032:analysis*; D029941:Fish Proteins / Q000737:chemistry / Q000276:immunology*; D005512:Food Hypersensitivity / Q000097:blood / Q000276:immunology; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry / Q000276:immunology*; D048389:Gadus morhua; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010320:Parvalbumins / Q000737:chemistry / Q000276:immunology; D010751:Phosphopyruvate Hydratase / Q000737:chemistry / Q000276:immunology*; D012474:Salmon; D014413:Tuna
chemical_list: D000485:Allergens; D029941:Fish Proteins; D010320:Parvalbumins; D007073:Immunoglobulin E; D005634:Fructose-Bisphosphate Aldolase; D010751:Phosphopyruvate Hydratase