Marjolein Wensing

Peanut allergen Ara h 3: Isolation from peanuts and biochemical characterization

Background:  Peanut allergen Ara h 3 has been the subject of investigation for the last few years. The reported data strongly depend on recombinant Ara h 3, since a purification protocol for Ara h 3 from peanuts was not available.

IgE Binding to Pepsin-Digested Food Extracts

Background: Pepsin resistance of allergens like lipid transfer protein and 2S albumin has been suggested as explanation for the severity of symptoms often induced by these allergens. Component-resolved diagnosis with purified labile and stable allergens has therefore been proposed to better characterize the risk involved in a positive in vitroIgE test. However, for many foods, purified allergens are not (yet) available. Objective: It was the aim of this study to evaluate the potential of pepsin-digested whole-food extracts to distinguish between IgE responses to stable (potentially severe) and labile (mild) allergens. Methods: Sera (n = 143) from Italian, Spanish and Dutch patients with hazelnut and/or apple ingestion-related symptoms were analyzed for residual IgE binding to pepsin-resistant hazelnut and/or apple allergens. Control and pepsin-digested hazelnut and apple extracts were used for radioallergosorbent test analysis and immunoblot analysis. Results: Pepsin digestion of food extracts, like from hazelnut and apple used for in vitro diagnostic tests, provides a way to distinguish sensitization to pepsin-resistant allergens from that to pepsin-susceptible allergens. In this selected group of patients, IgE reactivity to pepsin-digested extracts correlated with sensitization to the stable allergen lipid transfer protein. The analysis further revealed that the use of soluble pepsin can result in false-positive in vitro tests (2/143). Conclusion: Pepsin-digested food extracts are a convenient tool to identify patients with IgE antibodies against potentially dangerous stable allergens, in particular for those foods where the relevant stable allergens have not yet been identified. This can increase the clinical prognostic value of food allergy serology.

Anaphylaxis caused by the unexpected presence of casein in salmon.

A new process for restructured meat and fish has been introduced to the market recently. Its main compound is casein, and it may therefore endanger patients with a milk allergy.