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Background: Food allergy is a growing health concern with a prevalence of 2%–3% in the adult population in Europe. Non‐immune‐mediated food hypersensitivities, which include reactions after ingestion of food additives, affect 1% of adults and may resemble IgE‐induced allergic reactions without identifiable immunologic sensitization. A double‐blind placebo‐controlled food challenge (DBPCFC) is the gold standard for the diagnosis of any food hypersensitivity. Objective: We analysed a large group of adult patients with suspected food hypersensitivity, who had undergone DBPCFC, to better understand IgE‐mediated food allergy and non‐immune‐dependent food hypersensitivity to food additives in adults regarding elicitors, symptoms and positivity rates of oral challenges. Methods: Data from 541 patients with suspected food hypersensitivity were analysed, who underwent an oral food challenge between 2010 and 2019. Results: IgE‐dependent food allergy was confirmed in 114 of 329 adult patients (34.6%). The confirmation rate was lower in the group of patients with suspected non‐immune‐mediated reactions to food additives (65 of 286, 22.7%). Urticaria and angioedema appeared more frequently in patients with IgE‐mediated food allergies. By contrast, flush and diarrhoea were the most frequent symptoms after a challenge in the group with the non‐immune‐mediated reactions to food additives. Wheat and celery were the most frequently identified food allergens in adults, whereas colourings and preservatives were the most frequent elicitors of non‐immune‐mediated food hypersensitivity. Conclusion: The importance of oral food challenges for the diagnosis of food hypersensitivity is confirmed. IgE‐dependent food allergy is more frequently proven, reaching a positivity rate of one‐third and only about 20% for non‐immune‐mediated hypersensitivity. Future studies should elaborate on the mechanisms of non‐immune‐mediated food hypersensitivity and the clinical impact of cofactors in this setting. [ABSTRACT FROM AUTHOR]

Background: Systemic allergic reactions to vaccines are very rare. In this study we assessed the management and outcome of suspected SARS‐CoV‐2 vaccine hypersensitivity. Methods: Totally, 334 individuals underwent an allergy work up regarding SARS‐CoV‐2 vaccination (group A: 115 individuals suspected to be at increased risk for vaccine‐related reactions before vaccination and group B: 219 patients with reactions after COVID vaccination). The large majority of the SPT/IDT with the vaccines were negative; however, we identified in 14.1% (n = 47) a possible sensitization to the SARS‐CoV‐2 vaccine and/or its ingredients defined as one positive skin test. Of the 219 individuals (group B) who experienced symptoms suspicious for a hypersensitivity reaction after vaccination, 214 were reported after the first vaccination with a mRNA vaccine (157 mRNA (Comirnaty®, 38 Spikevax®) and 18 with a vector vaccine (Vaxzevria®), 5 cases were after the second vaccination. Results: The symptom profile in group B was as follows: skin symptoms occurred in 115 cases (n = 59 angioedema, n = 50 generalized urticaria and n = 23 erythema/flush. Seventy individuals had cardiovascular, 53 respiratory and 17 gastrointestinal symptoms. Of the overall 334 individuals, 78 patients tolerated (re)‐vaccination (out of skin test positive/negative 7/19 from group A and 17/35 from group B). Conclusion: Proven IgE‐mediated hypersensitivity to SARS‐CoV‐2 vaccines is extremely rare and not increased in comparison with reported hypersensitivity to other vaccines. The value of skin tests is unclear and nonspecific reactions, in particular when intradermal testing is applied, should be considered. [ABSTRACT FROM AUTHOR]

Background: Peanut allergy is a frequent cause of food allergy and potentially life‐threatening. Within this interdisciplinary research approach, we aim to unravel the complex mechanisms of peanut allergy. As a first step were applied in an exploratory manner the analysis of peanut allergic versus non‐allergic controls. Methods: Biosamples were studied regarding DNA methylation signatures, gut microbiome, adaptive and innate immune cell populations, soluble signaling molecules and allergen‐reactive antibody specificities. We applied a scalable systems medicine computational workflow to the assembled data. Results: We identified combined cellular and soluble biomarker signatures that stratify donors into peanut‐allergic and non‐allergic with high specificity. DNA methylation profiling revealed various genes of interest and stool microbiota differences in bacteria abundances. Conclusion: By extending our findings to a larger set of patients (e.g., children vs. adults), we will establish predictors for food allergy and tolerance and translate these as for example, indicators for interventional studies. [ABSTRACT FROM AUTHOR]

Background: Peanuts (PN) and tree nuts (TN) are among the most frequent elicitors of food allergy and can lead to life-threatening reactions. The current advice for allergic patients is to strictly avoid the offending food independently of their individual threshold level, whereas sensitized patients without allergic symptoms should frequently consume the food to avoid (re-)development of food allergy. The aim of this trial is to investigate (I) whether the consumption of low allergen amounts below the individual threshold may support natural tolerance development and (II) to what extent regular allergen consumption in sensitized but tolerant subjects prevents the (re-)development of PN or TN allergy.Methods: The TINA trial consisting of (part I) a randomized, controlled, open, parallel group, single-center, superiority trial (RCT), and (part II) a prospective observational exploratory cohort study. Children and adults (age 1-67 years) with suspected or known primary PN and/or TN allergy will undergo an oral food challenge (OFC) to determine their clinical reactivity and individual threshold. In the RCT, 120 PN or TN allergic patients who tolerate ≥100 mg of food protein will be randomized (1:1 ratio) to consumption of products with low amounts of PN or TN on a regular basis or strict avoidance for 1 year. The consumption group will start with 1/100 of their individual threshold, increasing the protein amount to 1/50 and 1/10 after 4 and 8 months, respectively. The primary endpoint is the clinical tolerance to PN or TN after 1 year assessed by OFC. In the cohort study, 120 subjects sensitized to PN and/or TN but tolerant are advised to regularly consume the food and observed for 1 year. The primary endpoint is the maintenance of clinical tolerance to PN and/or TN after 1 year assessed by challenging with the former tolerated cumulative dose.Discussion: This clinical trial will help to determine the impact of allergen consumption versus avoidance on natural tolerance development and whether the current dietary advice for PN or TN allergic patients with higher threshold levels is still valid.Trial Registration: German Clinical Trials Register; ID: DRKS00016764 (RCT), DRKS00020467 (cohort study). Registered on 15 January 2020, http://www.drks.de . [ABSTRACT FROM AUTHOR]