The extract, the molecular allergen or both for the in vitro diagnosis of peach and peanut sensitization?

Abstract

Introduction: Identifying the target molecule in food allergies, helps to assess the risk of anaphylaxis in a patient. Lipid Transfer Protein is the most frequent cause of food allergies in the Mediterranean area. The diagnosis based on allergenic extracts, suffers from a high variability in the results because some important allergenic molecules are lacking. This study was disegned to assess whether Pru p 3 and Ara h 9 molecules are quantitative and qualitative enough present in their whole allergenic extracts.

Methods: 943 patients with a clinical history of suspected peach and/or peanut food allergies were recruited and underwent measurement of a specific serum IgE (ImmunoCAP system (Thermofisher/Phadia Diagnostics, Uppsala, Sweden) to the following allergens and molecules: peach (f95) and/or peanut (f13), Pru p 3 (f420), Pru p 1 (f419), Pru p 4 (f421), Ara h 1 (f422), Ara h 2 (f423) Ara h 3 (f424) and Ara h 9 (f427).

Results: Out of the 943 patients included in this study, 122 were positive to sIgE to peanut extract. At a cut-off point of 0.35 kIU/L, 62 patients were positive to sIgE to Ara h 9 but negative to peanut extract. Increasing the cut-off point of Ara h 9 at 10 kIU/L, 15 patients were only positive to sIgE to Ara h 9. 244 out of the 943 patients were positive to sIgE to peach extract. At a cut-off point of 0.35 kIU/L, 27 patients were negative to sIgE to Pru p 3 and positive to sIgE to peach extract, whilst 11 patients were peach extract sIgE positive and sIgE negative to Pru p 1, Pru p 3 and Pru p 4. Only 12 patients resulted positive to Pru p1 and/or Pru p 4.

Conclusion: Our data strongly suggests to include the measurement of sIgE to Ara h 9 into the diagnostic algorithm of peanut sensitization. 4.5% of the sicilian population suspected of peach sensitization were positive to peach extract and negative to all the available molecules.