title: Tropomyosin IgE-positive results are a good predictor of shrimp allergy.
abstract: BACKGROUND
  Shrimp is a common cause of food allergy. Our aims were to determine the value of IgE antibodies in the diagnosis of shrimp allergy and to study red shrimp (Solenocera melantho) tropomyosin both as a new allergen and as a cross-reactive IgE-binding protein.
  
  
  METHODS
  We have studied 45 subjects. Skin prick test (SPT) was carried out in all subjects, and specific IgE (sIgE) to shrimp, recombinant and natural shrimp tropomyosins rPen a 1 and nPen m 1, recombinant Der p 10, and Dermatophagoides pteronyssinus was assessed by fluoroimmunoassay and/or immunoblotting. Double-blind, placebo-controlled food challenges were carried out to confirm diagnosis of shrimp allergy. Also, in vitro inhibition tests were performed to evaluate cross-reactivity.
  
  
  RESULTS
  Shrimp allergy was confirmed in 18 shrimp-allergic patients. Skin prick test and IgE antibodies to shrimp were positive in all shrimp-allergic patients; sIgE to rPen a 1 was detected in 98% of these patients. Of the 18 shrimp-tolerant patients, 61% had positive SPT to shrimp, 55% were IgE-positive to shrimp, and 33% showed IgE antibodies to rPen a 1. Determination of IgE to rPen a 1 yielded a positive predictive value of 0.72 and a negative predictive value of 0.91.
  
  
  CONCLUSIONS
  IgE levels to rPen a 1 provided additional value to the diagnosis of shrimp allergy. Some allergens in mite extract are recognized by patients who are allergic to shrimp, though their clinical relevance remains unknown.
authors.affiliation: Immunology Department, IIS-Fundación Jiménez Díaz, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Gámez
authors.forename: S
authors.initials: S
authors.lastname: Sánchez-García
authors.forename: M D
authors.initials: MD
authors.lastname: Ibáñez
authors.forename: R
authors.initials: R
authors.lastname: López
authors.forename: E
authors.initials: E
authors.lastname: Aguado
authors.forename: E
authors.initials: E
authors.lastname: López
authors.forename: B
authors.initials: B
authors.lastname: Sastre
authors.forename: J
authors.initials: J
authors.lastname: Sastre
authors.forename: V
authors.initials: V
authors.lastname: del Pozo
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions / Q000276:immunology; D005512:Food Hypersensitivity / Q000175:diagnosis* / Q000276:immunology*; D006801:Humans; D007114:Immunization; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008925:Mites / Q000276:immunology; D033561:Penaeidae / Q000276:immunology*; D012758:Shellfish / Q000009:adverse effects*; D014335:Tropomyosin / Q000276:immunology*; D055815:Young Adult
chemical_list: D000485:Allergens; D014335:Tropomyosin; D007073:Immunoglobulin E