Evaluation of sensitization to nsLTP proteins using allergen extracts and molecular components: a pilot study

Abstract

Background Non-specific Lipid Transfer proteins (nsLTP) are relevant allergens of several pollens and plant foods belonging to the widespread Rosaceae family and other distantly related species and can elicit systemic reactions in nsLTP-sensitized patients. In the last 20 years, sensitization to nsLTP and consequent reactions to plant foods has become an increasing concern. Therefore, accurate diagnosis in determining the sensitization to nsLTP is crucial. Standardizing the allergen extracts from fruits and vegetables is difficult because they may contain varying amounts of nsLTP due to varietal differences and growing, ripening, and storage conditions. This research aimed to evaluate the determination peculiarities of sensitization to nsLTP using allergen extracts and component analysis. Method The study included a total of 40 subjects (17 men and 23 women) aged 20 to 56 years with food allergies and/or symptoms of allergic rhinitis and/or allergic asthma. A skin prick test with inhalant and food allergens (Inmunotek, Spain) was done and specific IgE (sIgE) in blood serum by in vitro diagnostic systems: immunoblot EUROLINE (Euroimmun, Germany) and Alex2 (Macro Array Diagnostics GmbH, Austria) were determined. Results The results showed that 73.0 % of patients were sensitized to birch, 60.0 % to house dust mites, 52.5 % to mixed herbals and cat allergens. The molecular allergy diagnostic system results showed that 10 % of subjects were sensitized to nsLTP, and sIgE against mugwort was determined for 75 % of them (r=0.385, p = 0.016). The most common sensitization to molecular components belonging to the nsLTP protein family was Cor a 8, Ara h 9, Zea m14, Can s 3, act d 10, Mal d 3, and Vit v 1. The results showed that detecting sIgE against the extract of hazelnut allergens correlated with sIgE determination against a hazelnut molecular component belonging to the PR-10 family (r=0.433, p = 0.001) but did not correlate with the detection of sIgE against the component of Cor a 8, belonging to nsLTP (r=0.299, p>0.050). If the amount of sIgE against apple or peanut allergens extracts is higher than against birch extract, the sensitization to the allergens of nsLTP protein family could be suspected. Conclusion It was observed that molecular allergen diagnostics particulary valuable in determining sensitization to the nsLTP of proteins and associated cross-reactivity.