title: Usefulness of manufactured tomato extracts in the diagnosis of tomato sensitization: Comparison with the prick-prick method.
abstract: BACKGROUND
  Commercial available skin prick test with fruits can be negative in sensitized or allergic patients due to a reduction in biological activity during the manufacturing process. Prick-prick tests with fresh foods are often preferred, but they are a non-standardized procedure. The usefulness of freeze-dried extracts of Canary Islands tomatoes, comparing the wheal sizes induced by prick test with the prick-prick method in the diagnosis of tomato sensitization has been analyzed.The objective of the study was to assess the potential diagnostic of freeze-dried extracts of Canary Islands tomatoes, comparing the wheal sizes induced by prick test with the prick-prick method.
  
  
  METHODS
  Two groups of patients were analyzed: Group I: 26 individuals reporting clinical symptoms induced by tomato contact or ingestion. Group II: 71 control individuals with no symptoms induced by tomato: 12 of them were previously skin prick test positive to a tomato extract, 39 were atopic and 20 were non-atopic. All individuals underwent prick-prick with fresh ripe peel Canary tomatoes and skin prick tested with freeze-dried peel and pulp extracts obtained from peel and pulp of Canary tomatoes at 10 mg/ml. Wheal sizes and prick test positivity (>/= 7 mm2) were compared between groups.
  
  
  RESULTS
  In group I, 21 (81%) out of 26 patients were prick-prick positive. Twenty patients (77%) had positive skin prick test to peel extracts and 12 (46%) to pulp extracts. Prick-prick induced a mean wheal size of 43.81 +/- 40.19 mm2 compared with 44.25 +/- 36.68 mm2 induced by the peel extract (Not significant), and 17.79 +/- 9.39 mm2 induced by the pulp extract (p < 0.01).In group II, 13 (18%) out of 71 control patients were prick-prick positive. Twelve patients (all of them previously positive to peel extract) had positive skin prick test to peel and 3 to pulp. Prick-prick induced a mean wheal size of 28.88 +/- 13.12 mm2 compared with 33.17 +/- 17.55 mm2 induced by peel extract (Not significant), and 13.33 +/- 4.80 mm2 induced by pulp extract (p < 0.05 with peel extract and prick-prick).
  
  
  CONCLUSIONS
  Canary peel tomato extract seems to be as efficient as prick-prick tests with ripe tomatoes to diagnose patients sensitized to tomato. The wheal sizes induced by prick-prick and peel extracts were very similar and showed a high correlation coefficient.
authors.affiliation: Research & Development Department, Laboratorios LETI, S,L,, Tres Cantos, Madrid, Spain. jcarnes@leti.com.
authors.forename: Angel
authors.initials: A
authors.lastname: Ferrer
authors.forename: Angel J
authors.initials: AJ
authors.lastname: Huertas
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Larramendi
authors.forename: Jose L
authors.initials: JL
authors.lastname: García-Abujeta
authors.forename: Joan
authors.initials: J
authors.lastname: Bartra
authors.forename: Jose R
authors.initials: JR
authors.lastname: Lavín
authors.forename: Carmen
authors.initials: C
authors.lastname: Andreu
authors.forename: Juan A
authors.initials: JA
authors.lastname: Pagán
authors.forename: María A
authors.initials: MA
authors.lastname: López-Matas
authors.forename: Enrique
authors.initials: E
authors.lastname: Fernández-Caldas
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Carnés