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Background: Fruit allergy has been attributed to cross-reactive IgE to pollens and has been associated with a particular pollen sensitization., Objective: The aim of the study was to evaluate sensitization to several taxonomically unrelated pollens in peach- and pollen-allergic patients and to study cross-reactivity between them., Methods: One hundred sixty-five patients were evaluated: 70 peach- allergic patients together with 95 pollen-allergic patients (control group). Pollen skin tests in duplicate were performed to 5 grasses, 8 trees, and 7 weeds. Cross-reactivity between peach and taxonomically diverse pollens was determined by radioallergosorbent inhibition and Western blot inhibition tests. Experiments were also carried out after preadsorption of the sera with purified natural profilin., Results: The skin test results revealed that peach-allergic patients frequently reacted to most pollens-grasses, weeds, and trees-even when some of these are not found in our geographic area. There was a statistically significant increase in sensitization frequency to most trees and weeds, with a statistically higher occurrence of asthma (odds ratio 2.98, 95% confidence interval 1.46-6.09). Inhibition test results provided evidence that taxonomically unrelated grasses, weeds, and trees produced various and substantial degrees of inhibition in specific IgE to peach and that the peach extract elicited strong inhibitions to those pollens. Profilin was found to be a relevant cross-reactive antigen in these patients., Conclusion: The results of this study provide evidence that peach allergy is linked to sensitization to several taxonomically unrelated pollens. This is attributable to the ubiquitous nature of the IgE binding determinants-such as profilins-between peach and taxonomically unrelated pollens.

Objective: The aim of this study was to develop a quantitative skin test assay for measurement of the biologic activity of food allergen extracts, as well as to report the results obtained with a peach extract labeled in food biological units (FBUs)., Methods: We prepared a biologically quantified peach extract. The biologic activity was measured in FBUs by assigning 100 FBU/ml to the biologic activity of the extract that elicited a wheal area with a geometric mean equal to that produced by the prick-prick method by using the food itself in a population of 30 patients allergic to food. We evaluated 265 patients, including 70 patients allergic to peach and 195 control subjects (100 nonatopic subjects and 95 subjects allergic to pollen). The biologically quantified peach extract was used during the study and was compared with four commercial peach extracts, which were labeled in weight per volume., Results: The sensitivity of the nonstandardized commercial peach extracts varied from 4.3% to 74%, with biologic activity being very low in all of them. The sensitivity of the biologically quantified peach extract was 100%, with a 100% concordance between the prick-prick and the skin prick test results., Conclusion: These data demonstrate that if peach allergen preparations were biologically standardized in FBUs, the quality of these food extracts used for diagnosis would be improved.