Allergen-based microarray is a tool for the detection of IgE-related sensitization to panels of allergens and gives a more precise and comprehensive evaluation for an IgE-based epidemiology. This insight brings data for better understanding of the sensitization process.

Background: Diagnosis and immunotherapy of house-dust mite (HDM) allergy is still based on natural allergen extracts. The aim of this study was to analyze commercially available Dermatophagoides pteronyssinus extracts from different manufacturers regarding allergen composition and content and whether variations may affect their allergenic activity. Methods: Antibodies specific for several D. pteronyssinus allergens (Der p 1, 2, 5, 7, 10 and 21) were used to analyze extracts from 10 different manufacturers by immunoblotting. Sandwich ELISAs were used to quantify Der p 1 and Der p 2 in the extracts. Mite-allergic patients (n = 45) were skin-tested with the extracts and tested for immunoglobulin E (IgE) reactivity to a panel of 10 mite allergens (Der p 1, 2, 4, 5, 7, 8, 10, 14, 20 and 21) by dot blot. Results: Only Der p 1 and Der p 2 were detected in all extracts but their concentrations and ratios showed high variability (Der p 1: 6.0–40.8 µg ml^–1; Der p 2: 1.7–45.0 µg ml^–1). At least 1 out of 4 allergens (i.e. Der p 5, 7, 10 and 21) was not detected in 8 of the studied extracts. Mite-allergic subjects showed different IgE reactivity profiles to the individual mite allergens, the extracts showed different allergenic activity in skin-prick tests and false-negative results. Conclusions: Commercially available D. pteronyssinus extracts lack important allergens, show great variability regarding allergen composition and content and some gave false-negative diagnostic test results in certain patients.

Background Among the peach-derived allergens which are already known, the lipid transfer protein (Pru p 3) seems to be the one to exert severe allergic reactions. Objective To identify and characterize a new peach allergen causing a clinical picture similar to that of Pru p 3. Methods Patients were selected on the basis of their severe clinical reactivity and negative results to a panel of peach allergens available on the ISAC103 microarray. Several inhouse and commercial preparations were compared. Several methods were used to characterize the newly identified molecule. Specific IgE and inhibition assays were performed using the Allergen micro-Beads Array (ABA) assay. Results Negative ISAC results to Pru p 3 were confirmed by additional testing in contrast with the positive results obtained by commercial Pru p 3-enriched peach peel extracts. The analyses of one of these preparations led to the identification of Peamaclein, a new allergenic protein. It is a small, basic, cysteine-rich, heat-stable, digestion-resistant protein, homologous to a potato antimicrobial peptide. Peamaclein was able to trigger positive skin test reactions and to bind IgE in the ABA assay. It displays an electrophoretic mobility and chromatographic behaviour similar to that of Pru p 3; therefore, it can be hidden in Pru p 3 preparations. In fact, Pru p 3-enriched peach peel extracts were found to contain both Pru p 3 and Peamaclein by means of comparative in vivo testing, and by biochemical and immunochemical assays. Commercially available anti-Pru p 3 polyclonal antibodies were found to have a double specificity for the two molecules. Conclusions and Clinical Relevance A new allergen from peach belonging to a new family of allergenic proteins has been identified and characterized. This knowledge on Peamaclein will improve our understanding on the clinical aspects of the peach allergy and the quality of diagnostic reagents.

Background Egg allergy is a very common finding in early childhood. Detecting hen's egg (HE) allergy outgrowing and reintroduction of food containing egg is a task for the allergist.Objective We sought to evaluate the suitability of boiled egg food challenge compared with IgE to allergenic molecules from HE white using a microarray system. Method Sixty-eight children referring to our centre by the family paediatricians for a suspected egg allergy were enrolled. Patients underwent double-blind, placebo-controlled food challenge with boiled and raw eggs. Challenge outcomes were compared with skin tests performed using egg white and yolk commercial extracts, to prick-prick test with boiled and raw egg white and yolk, total IgE, egg white specific IgE detected using Immu-noCAP and IgE to egg allergens available on the immunosolid phase allergen chip (ISAC) 103 microarray. Result Nineteen subjects (28%) were reactive to both raw and boiled egg, 14 (20.5%) to raw egg only and 35 (51.4%) tolerated both boiled and raw egg. Efficiency analysis was carried out using both raw and boiled egg challenges as gold standard. Forty four of 47 Gal d 1 negative patients tolerated boiled egg (94%). Conversely, 20 of 21 Gal d 1 positive patients reacted to raw egg (95%). None of the other tests was able to discriminate patients' response to HE challenge. Furthermore, Gal d 1 positivity seems to lead to broader environmental allergen IgE sensitization. Conclusion and Clinical Relevance The Gal d 1 IgE reactivity appears to be a very good predictor of HE clinical allergy. Gal d 1 positive children have a high frequency of HE allergy, whereas Gal d 1 negative children have a high frequency of tolerance to boiled egg. Multiple specific IgE detection by means of ISAC improves the diagnostic approach in HE allergic children, disclosing other food and inhalant allergic sensitizations, anyhow requiring a comprehensive clinical evaluation.

It has been suggested that changes in dietary habits, particularly increased consumption of omega-6 polyunsaturated fatty acids (PUFA) and decreased consumption of omega-3 PUFAs may explain the increase in atopic disease seen in recent years. Furthermore, it seems possible that it is mainly prenatal or very early life environmental factors that influence the development of allergic diseases. It has also been suggested that intrauterine risk factors may act differently if mother themselves suffer from allergic disease. The aim of this study was to investigate whether the consumption of fish, butter and margarine during pregnancy might influence the development of allergic sensitizations in the offspring. The study population was divided into the offspring of allergic and non-allergic mothers. This was a retrospective cohort study enrolling 295 offspring of allergic mothers and 693 of non-allergic mothers. Information regarding maternal intake of fish, butter and margarine during pregnancy as well as other prenatal and perinatal confounding factors were retrospectively assessed by parental report via a standardized questionnaire. Atopy was determined by skin-prick tests (SPT) to eight prevalent inhalant allergens and two foods. In the allergic mothers' group there is no clear correlation between maternal intakes of fish, butter and margarine and sensitizations to food or inhalants. In the non-allergic mothers' group there was no correlation between butter and margarine intake and food or inhalant sensitizations. On the contrary, a protective effect of fish intake on SPT positivity was observed. In particular, frequent maternal intake ('2-3 times/wk or more') of fish reduced the risk of food sensitizations by over a third (aOR 0.23; 95% CI: 0.08-0.69). A similar trend, even if not significant, was found for inhalants. Finally, even in the whole study population, i.e. allergic group plus non-allergic group, there was a similar trend between increased consumption of fish and decreased prevalence of SPT positivity for foods. This study shows that frequent intake of fish during pregnancy may contrast the development of SPT sensitizations for foods in the offspring of mothers without atopic disease. Therefore, larger prospective studies are needed, enrolling mothers with and without allergic disease, to confirm these results.