Allergen Recognition Patterns in Walnut Allergy Are Age Dependent and Correlate with the Severity of Allergic Reactions

Enhancing the diagnostic accuracy of the IgE crosslinking-induced luciferase expression (EXiLE) method for walnut allergy

BACKGROUND

Walnut (Juglans regia) frequently triggers nut allergies in the United Kingdom and in the United States, with increasing cases in Japan. While oral food challenges (OFCs) are the definitive method for diagnosing these allergies, they pose the risk of symptom provocation, necessitating safer alternative tests. Our aim here was to evaluate the diagnostic utility of IgE (immunoglobulin E) crosslinking-induced luciferase expression (EXiLE) for walnut allergy compared with the walnut-specific IgE (sIgE) test, Jug r 1-sIgE test, and skin prick test (SPT).

METHODS

This retrospective study analyzed 55 patients tested for walnut allergy (WA) at Fujita Health University Bantane Hospital from January 2021 to December 2023. Among them, 38 had allergic reactions to walnuts based on history or OFCs and 17 did not. We evaluated the sensitivity, specificity, positive predictive value, negative predictive value, and the area under the curve (AUC) of the receiver operating characteristic curve.

RESULTS

The EXiLE method (AUC = 0.938) exhibited superior diagnostic accuracy compared to the walnut-sIgE and comparable performance to Jug r 1-sIgE and SPT. The optimal cutoff value of 1.26-fold change demonstrated high sensitivity (0.92), specificity (0.88), positive predictive value (0.92), and negative predictive value (0.82). The EXiLE method yielded positive results in all three cases with negative Jug r 1-sIgE (< 0.35 UA/mL).

CONCLUSION

The EXiLE method showed high sensitivity and specificity for diagnosing WA, indicating its potential clinical utility. Furthermore, the combination of Jug r 1-sIgE and EXiLE may enhance diagnostic accuracy. Future large-scale studies are warranted to confirm these findings and establish comprehensive diagnostic protocols.

Association of Mite Molecular Sensitization Profiles with Respiratory Allergies and Asthma Control in Children from East China

Background

Allergic conditions, identified as a significant global health challenge, are profoundly influenced by indoor allergens, especially house dust mites (HDM). Yet the relationship between mite sensitized components and respiratory allergies and asthma control remains poorly understood.

Methods

A cohort of 96 children, either with allergic rhinitis (AR) or rhinitis with asthma syndrome (ARAS), was assessed. Protein microarray technology was deployed to quantify sIgE responses to the allergenic components of Der p and Der f.

Results

The study cohort comprised 18 AR and 78 ARAS patients; with 43 mild and 53 moderate-to-severe AR; with 28 uncontrolled, 21 partially controlled, and 29 well-controlled asthma. Sensitization prevalence for HDM components was highest with Der p (97.9%), Der f 2 (97.9%), Der p 2 (94.8%), Der f 1(94.8%), Der p 1 (93.8%), Der p 23 (57.3%). Notably, sIgE concentrations for Der f and Der f 2 were significantly greater in the ARAS compared to AR (P < 0.05). While sIgE levels varied between mild and moderate-to-severe AR, the differences were not statistically significant (P > 0.05). However, Der p 23 sIgE levels demonstrated a significant fluctuation across the asthma control strata (P < 0.05), with the well-controlled group exhibiting the lowest readings.

Conclusion

The sIgE levels to HDM allergens were higher in ARAS group compared to AR group, especially Der f and Der f 2, indicating an association between sIgE reactivity and the diagnosis of asthma. Reduced Der p 23 sIgE levels were indicative of enhanced asthma control.

Poppy Seed Allergy: Molecular Diagnosis and Cross-Reactivity With Tree Nuts

BACKGROUND

Poppy seed (PS) can be a cause of severe allergic reactions, especially in individuals with concurrent allergy to tree nuts and other seeds, but diagnostic criteria and sensitization patterns are lacking.

OBJECTIVE

To assess the role of PS extract and individual allergens in diagnosing PS allergy and their cross-reactivities with tree nuts and buckwheat.

METHODS

Our retrospective study included 36 PS-sensitized patients; 10 with a positive and 26 with a negative oral food challenge (OFC). We identified individual PS allergens and compared the diagnostic performance of specific IgE (sIgE) to PS extract with its allergens. Cross-reactivities between PS and related allergens from other seeds were assessed by a competitive enzyme-linked immunosorbent assay.

RESULTS

We identified 4 novel PS allergens: Pap s 1 (vicilin), Pap s 1 (27-424) (α-hairpinin), Pap s 2 (legumin), and Pap s 3 (small hydrophilic seed protein). A positive OFC correlated with higher PS-sIgE levels and elevated sIgE levels for the PS allergens, except for Pap s 3. PS and α-hairpinin-sIgE effectively differentiated allergic from tolerant patients, with area under the curve values of 0.95 and 0.94. PS-sIgE >10.00 kUA/L exhibited 90% sensitivity and 73% specificity, whereas α-hairpinin-sIgE >2.60 kUA/L showed 100% sensitivity and 77% specificity. PS vicilin and legumin highly cross-reacted with hazelnut and buckwheat homologs, whereas α-hairpinin-sIgE cross-reacted with the related almond allergen.

CONCLUSIONS

This is the most extensive study on PS allergy to date. PS and α-hairpinin-sIgE are highly sensitive indicators of clinical reactivity to PS, whereas vicilin and legumin-sIgE contribute to concurrent sensitization to hazelnut and buckwheat.

Tolerance of peanuts and tree nuts in Spanish children with exclusive sensitization to lipid transfer proteins

BACKGROUND

Allergy to peanuts and tree nuts is a common cause of food allergy in Spain, with lipid transfer proteins (LTP) being the most frequently recognized panallergen. LTP sensitization often leads to multiple food group sensitivities, resulting in overly restrictive diets that hinder patient's quality of life. This study aimed to assess the tolerance of peanuts and tree nuts (hazelnuts and walnuts) in children sensitized to LTP, potentially mitigating the need for such diets.

METHODS

This prospective study enrolled individuals diagnosed with allergy to peanuts, hazelnuts, or walnuts. Data were collected from medical records, including demographics and clinical history. Allergological assessment comprised skin prick tests using commercial extracts and the nuts in question, alongside measurements of total and specific IgE to nuts and their primary molecular components. Participants showing positive LTP sensitization without sensitization to seed storage proteins underwent open oral nut challenges.

RESULTS

A total of 75 individuals labeled as allergic to peanuts, 44 to hazelnuts, and 51 to walnuts were included. All of them underwent an open oral provocation test with the incriminated nut, showing a high tolerance rate. Peanut was tolerated by 98.6% of patients, 97.72% tolerated hazelnut, and 84.3% tolerated walnut.

CONCLUSION

The findings suggest that the majority of patients allergic to peanuts, hazelnuts, or walnuts, due to LTP sensitization and lacking IgE reactivity to seed storage proteins, can tolerate these nuts. This supports the need for personalized nut tolerance assessments to avoid unnecessary dietary restrictions.

Precision allergy molecular diagnosis applications in food allergy

PURPOSE OF REVIEW

Precision medicine has become important in the diagnosis and management of food allergies. This review summarizes the latest information regarding molecular allergology, an essential component of food allergy managements.

RECENT FINDINGS

Component-resolved diagnostics (CRD) can be used to investigate sensitization to allergens based on symptoms and to reveal co-sensitization and/or cross-sensitization in patients with allergies. The following allergen components are known to be associated with symptoms: ovomucoid from eggs, omega-5 gliadin from wheat, and many storage proteins (Gly m 8 from soy, Ara h 2 from peanut, Cor a 14 from hazelnut, Ana o 3 from cashew nut, Jug r 1 from walnut, and Ses i 1 from sesame). Recent studies on allergens of macadamia nuts (Mac i 1 and Mac i 2), almonds (Pru du 6), fish (parvalbumin and collagen), and shrimp (Pem m 1 and Pem m 14) have provided additional information regarding CRD. In addition, Pru p 7 is a risk factor for systemic reactions to peaches and has recently been found to cross-react with cypress and Japanese cedar pollen.

SUMMARY

CRD provides information of individualized sensitization profiles related to symptoms and severity of allergies in patients. Clinical practice based on CRD offers many benefits, such as higher diagnostic accuracy and improved management of individual patients.

Current options in the management of tree nut allergy: A systematic review and narrative synthesis

Tree nut allergy is a lifelong and potentially life-threatening condition. The standard of care is strictly avoiding the culprit nut and treating accidental reactions symptomatically. To evaluate potential therapeutic options for desensitizing patients with IgE-mediated tree nut allergy, we systematically searched three bibliographic databases for studies published until January 2024. We looked for active treatments of IgE-mediated allergy to tree nuts (walnut, hazelnut, pistachio, cashew, almond, pecan, macadamia nut, and brazil nut). We focused on allergen-specific immunotherapy (AIT) using oral (OIT), sublingual (SLIT), epicutaneous (EPIT), or subcutaneous (SCIT) delivery, or other disease-modifying treatments. We found 19 studies that met our criteria: 3 studies investigated sublingual immunotherapy, 5 studied oral immunotherapy to a single tree nut, and 6 used multi-food oral immunotherapy with or without omalizumab. The remaining studies investigated the effectiveness of monoclonal antibodies or IgE-immunoadsorption in multi-food allergic patients, including patients with tree nut allergy. The heterogeneity of the studies prevented pooling and meta-analysis. Oral immunotherapy, single or multi-nut, with or without omalizumab, was the most studied approach and appears effective in conferring protection from accidental exposures. Omalizumab monotherapy is the only approved alternative management for reducing allergic reactions that may occur with accidental exposure.

A systematic review of allergen cross-reactivity: Translating basic concepts into clinical relevance

Access to the molecular culprits of allergic reactions allows for the leveraging of molecular allergology as a new precision medicine approach-one built on interdisciplinary, basic, and clinical knowledge. Molecular allergology relies on the use of allergen molecules as in vitro tools for the diagnosis and management of allergic patients. It complements the conventional approach based on skin and in vitro allergen extract testing. Major applications of molecular allergology comprise accurate identification of the offending allergen thanks to discrimination between genuine sensitization and allergen cross-reactivity, evaluation of potential severity, patient-tailored choice of the adequate allergen immunotherapy, and prediction of its expected efficacy and safety. Allergen cross-reactivity, defined as the recognition of 2 or more allergen molecules by antibodies or T cells of the same specificity, frequently interferes with allergen extract testing. At the mechanistic level, allergen cross-reactivity depends on the allergen, the host's immune response, and the context of their interaction. The multiplicity of allergen molecules and families adds further difficulty. Understanding allergen cross-reactivity at the immunologic level and translating it into a daily tool for the management of allergic patients is further complicated by the ever-increasing number of characterized allergenic molecules, the lack of dedicated resources, and the need for a personalized, patient-centered approach. Conversely, knowledge sharing paves the way for improved clinical use, innovative diagnostic tools, and further interdisciplinary research. Here, we aimed to provide a comprehensive and unbiased state-of-the art systematic review on allergen cross-reactivity. To optimize learning, we enhanced the review with basic, translational, and clinical definitions, clinical vignettes, and an overview of online allergen databases.

Systematic review and meta-analyses on the accuracy of diagnostic tests for IgE-mediated food allergy

The European Academy of Allergy and Clinical Immunology (EAACI) is updating the Guidelines on Food Allergy Diagnosis. We aimed to undertake a systematic review of the literature with meta-analyses to assess the accuracy of diagnostic tests for IgE-mediated food allergy. We searched three databases (Cochrane CENTRAL (Trials), MEDLINE (OVID) and Embase (OVID)) for diagnostic test accuracy studies published between 1 October 2012 and 30 June 2021 according to a previously published protocol (CRD42021259186). We independently screened abstracts, extracted data from full texts and assessed risk of bias with QUADRAS 2 tool in duplicate. Meta-analyses were undertaken for food-test combinations for which three or more studies were available. A total of 149 studies comprising 24,489 patients met the inclusion criteria and they were generally heterogeneous. 60.4% of studies were in children ≤12 years of age, 54.3% were undertaken in Europe, ≥95% were conducted in a specialized paediatric or allergy clinical setting and all included oral food challenge in at least a percentage of enrolled patients, in 21.5% double-blind placebo-controlled food challenges. Skin prick test (SPT) with fresh cow's milk and raw egg had high sensitivity (90% and 94%) for milk and cooked egg allergies. Specific IgE (sIgE) to individual components had high specificity: Ara h 2-sIgE had 92%, Cor a 14-sIgE 95%, Ana o 3-sIgE 94%, casein-sIgE 93%, ovomucoid-sIgE 92/91% for the diagnosis of peanut, hazelnut, cashew, cow's milk and raw/cooked egg allergies, respectively. The basophil activation test (BAT) was highly specific for the diagnosis of peanut (90%) and sesame (93%) allergies. In conclusion, SPT and specific IgE to extracts had high sensitivity whereas specific IgE to components and BAT had high specificity to support the diagnosis of individual food allergies.

History and Utility of Specific IgE Cutoff Levels: What is the Relevance for Allergy Diagnosis?

Allergy is defined clinically, by symptoms on allergen exposure. A patient is considered sensitized when allergen-specific IgE (sIgE) antibody can be detected in serum or plasma or a skin test result is positive, even if no clinical reaction has been experienced. Sensitization should be regarded as a requisite and risk factor for allergy but is not synonymous with an allergy diagnosis. To provide a correct allergy diagnosis, test results regarding allergen-sIgE must always be considered in view of the patient's case history and clinical observations. Correct assessment of a patient's sensitization to specific allergens relies on the use of accurate and quantitative methods for detection of sIgE antibodies. The evolution of sIgE immunoassays toward higher analytical performance and the use of different cutoff levels in the interpretation of test results sometimes cause confusion. Earlier versions of sIgE assays offered a limit of quantitation of 0.35 kilounits of sIgE per liter (kUA/L), which also became an established cutoff level for a positive test result in the clinical use of the assays. Current sIgE assays are capable of reliably measuring sIgE levels as low as 0.1 kUA/L and can thereby demonstrate sensitization in cases in which previous assays could not. When the outcome of sIgE test results is evaluated, it is critically important to distinguish between the analytical data as such and their clinical interpretation. Even though sIgE may be present in the absence of symptoms of allergy, available information suggests that sIgE concentrations between 0.1 kUA/L and 0.35 kUA/L may be clinically relevant in some individuals, not least among children, although this should be further evaluated for various allergies. Moreover, it is becoming widely adopted that nondichotomous interpretation of sIgE levels may offer a diagnostic benefit compared with using a predefined cutoff level.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

CD4+CD25+CD127loFOXP3+ cell in food allergy: Does it predict anaphylaxis?

BACKGROUND

Food allergy (FA), hence the incidence of food anaphylaxis, is a public health problem that has increased in recent years. There are still no biomarkers for patients with FA to predict severe allergic reactions such as anaphylaxis.

OBJECTIVE

There is limited information on whether regulatory T (Treg) cell levels are a biomarker that predicts clinical severity in cases presenting with FA, and which patients are at a greater risk for anaphylaxis.

METHODS

A total of 70 children were included in the study: 25 who had IgE-mediated cow's milk protein allergy (CMPA) and presented with non-anaphylactic symptoms (FA/A-), 16 who had IgE-mediated CMPA and presented with anaphylaxis (FA/A+) (a total of 41 FA cases), and a control group consisting of 29 children without FA. The study was conducted by performing CD4+CD25+CD127^loFOXP3+ cell flow cytometric analysis during resting at least 2 weeks after the elimination diet to FA subjects.

RESULTS

When the FA group was compared with healthy control subjects, CD4+CD25+CD127_loFOXP3+ cell rates were found to be significantly lower in the FA group (p < 0.001). When the FA/A- and FA/A+ groups and the control group were compared in terms of CD4+CD25+CD127^loFOXP3+ cell ratios, they were significantly lower in the FA/A- and FA/A+ groups compared to the control group (p < 0.001).

CONCLUSIONS

Although there was no significant difference between the FA/A+ group and the FA/A- group in terms of CD4+CD25+CD127^loFOXP3+ cells, our study is important, as it is the first pediatric study we know to investigate whether CD4+CD25+CD127^loFOXP3+ cells in FA predict anaphylaxis.

Risk factors for severe reactions in food allergy: Rapid evidence review with meta-analysis

This rapid review summarizes the most up to date evidence about the risk factors for severe food-induced allergic reactions. We searched three bibliographic databases for studies published between January 2010 and August 2021. We included 88 studies and synthesized the evidence narratively, undertaking meta-analysis where appropriate. Significant uncertainties remain with respect to the prediction of severe reactions, both anaphylaxis and/or severe anaphylaxis refractory to treatment. Prior anaphylaxis, an asthma diagnosis, IgE sensitization or basophil activation tests are not good predictors. Some molecular allergology markers may be helpful. Hospital presentations for anaphylaxis are highest in young children, yet this age group appears at lower risk of severe outcomes. Risk of severe outcomes is greatest in adolescence and young adulthood, but the contribution of risk taking behaviour in contributing to severe outcomes is unclear. Evidence for an impact of cofactors on severity is lacking, although food-dependent exercise-induced anaphylaxis may be an exception. Some medications such as beta-blockers or ACE inhibitors may increase severity, but appear less important than age as a factor in life-threatening reactions. The relationship between dose of exposure and severity is unclear. Delays in symptom recognition and anaphylaxis treatment have been associated with more severe outcomes. An absence of prior anaphylaxis does not exclude its future risk.

Impact of Food Matrices on Digestibility of Allergens and Poorly Allergenic Homologs

Background

Protease resistance is considered a risk factor for allergenicity of proteins, although the correlation is low. It is nonetheless a part of the weight-of-evidence approach, proposed by Codex, for assessing the allergenicity risk of novel food proteins. Susceptibility of proteins to pepsin is commonly tested with purified protein in solution.

Objective

Food proteins are rarely consumed in purified form. Our aim was to evaluate the impact of experimental and endogenous food matrices on protease susceptibility of homologous protein pairs with different degrees of allergenicity.

Methods

Porcine and shrimp tropomyosin (ST) were subjected to sequential exposure to amylase, pepsin, and pancreatin in their respective endogenous matrix (pork tenderloin/boiled shrimp) and in three different experimental matrices (dessert mousse [DM], soy milk [SM], and chocolate bar [CB]). Digestion was monitored by immunoblotting using tropomyosin-specific antibodies. Recombinant peach and strawberry lipid transfer protein were biotinylated, spiked into both peach and strawberry fruit pulp, and subjected to the same sequential digestion protocol. Digestion was monitored by immunoblotting using streptavidin for detection.

Results

Chocolate bar, and to a lesser extent SM, had a clear protective effect against pepsin digestion of porcine tropomyosin (PT) and to a lesser extent of ST. Increased resistance was associated with increased protein content. Spiking experiments with bovine serum albumin (BSA) confirmed the protective effect of a protein-rich matrix. The two tropomyosins were both highly resistant to pepsin in their protein-rich and lean native food matrix. Pancreatin digestion remained rapid and complete, independent of the matrix. The fat-rich environment did not transfer protection against pepsin digestion. Spiking of recombinant peach and strawberry lipid transfer proteins into peach and strawberry pulp did not reveal any differential protective effect that could explain differences in allergenicity of both fruits.

Conclusions

Protein-rich food matrices delay pepsin digestion by saturating the protease. This effect is most apparent for proteins that are highly pepsin susceptible in solution. The inclusion of food matrices does not help in understanding why some proteins are strong primary sensitizers while homologs are very poor allergens. Although for induction of symptoms in food allergic patients (elicitation), a protein-rich food matrix that may contribute to increased risk, our results indicate that the inclusion of food matrices in the weight-of-evidence approach for estimating the potential risks of novel proteins to become allergens (sensitization), is most likely of very limited value.

Components of plant-derived food allergens: Structure, diagnostics, and immunotherapy

A large number of plant-derived food allergen components have been identified to date. Although these allergens are diverse, they often share common structural features such as numerous disulfide bonds or oligomeric structures. Furthermore, some plant-derived food allergen components cross-react with pollen allergens. Since the relationship between allergen components and clinical symptoms has been well characterized, measurements of specific IgE to these components have become useful for the accurate clinical diagnosis and selection of optimal treatment methods for various allergy-related conditions including allergy caused by plant-derived foods. Herein, I have described the types and structures of different plant allergen components and outlined the diagnosis as well as treatment strategies, including those reported recently, for such substances. Furthermore, I have also highlighted the contribution of allergen components to this field.

Improving Diagnostic Accuracy in Food Allergy

The diagnosis of food allergy can have a major impact on the lives of patients and families, imposing dietary restrictions and limitations on social activities. On the other hand, misdiagnosis can place the patient at risk of a potentially severe allergic reaction. Therefore, an accurate diagnosis of food allergy is of utmost importance. The diagnosis of food allergy is often established by the combination of the clinical history and allergen-specific IgE; however, without a clear history of an allergic reaction, the interpretation of IgE sensitization tests can be difficult. There are also rare cases of clinical food allergy in the absence of IgE sensitization. For that reason, testing for suspected food allergy ideally requires access to oral food challenges (OFCs), which are currently the gold standard tests to diagnose food allergy. As OFCs are time consuming and involve the risk of acute allergic reactions of unpredictable severity, the question remains: how can we improve the accuracy of diagnosis before referring the patient for an OFC? Herein, we review the predictive value of different tests used to support the diagnosis of food allergy, discuss implications for therapy and prognosis, and propose a diagnostic approach to be applied in clinical practice.

Survey of Commercial Food Products for Detection of Walnut (Juglans regia) by Two ELISA Methods and Real Time PCR

Labeling of food allergens in accordance with legal regulations is important to protect the health of allergic consumers. The requirements for detecting allergens in foods involve adequate specificity and sensitivity to identify very small amounts of the target allergens in complex food matrices and processed foods. In this work, one hundred commercial samples were analyzed for walnut detection using three different methods: a sandwich enzyme-linked immunosorbent assay (ELISA) kit based on polyclonal antibodies, a direct ELISA using a recombinant multimeric scFv, and a real time PCR. The most sensitive method was real time PCR followed by sandwich ELISA kit and multimeric scFv ELISA. There was agreement between the three methods for walnut detection in commercial products, except for some heat-treated samples or those that contained pecan. The walnut ELISA kit was less affected by sample processing than was the multimeric scFv ELISA, but there was cross-reactivity with pecan, producing some false positives that must be confirmed by real time PCR. According to the results obtained, 7.0 to 12.6% of samples (depending on the analytical method) contained walnut but did not declare it, confirming there is a risk for allergic consumers. Moreover, there was one sample (3.7%) labelled as containing walnut but that tested negative for this tree nut. Genetic and immunoenzymatic techniques offer complementary approaches to develop a reliable verification for walnut allergen labeling.

The Role of Lipid Transfer Proteins as Food and Pollen Allergens Outside the Mediterranean Area

PURPOSE OF REVIEW

To provide an overview of the prevalence and clinical manifestation of non-specific lipid transfer proteins (LTP)-mediated allergies outside the Mediterranean area and to address potential reasons for the different geographical significance of LTP-driven allergies.

RECENT FINDINGS

LTPs are major allergens in the Mediterranean area, which frequently can elicit severe reactions. Pru p 3 the LTP from peach is reported as genuine allergen and is considered a prototypic marker for LTP-mediated allergies. However, both food and pollen LTP allergies exist outside the Mediterranean area, but with lower clinical significance, different immunogenicity, and less clarified role. Evidence has been reported that in areas with high exposure to pollen, in particular to mugwort, pollen-derived LTPs can act as a primary sensitizer to trigger secondary food allergies. Co-sensitization to unrelated allergens might be causative for less severe reactions in response to LTPs. However, the reason for the geographical different sensitization patterns to LTPs remains unclear.

Biomarkers for diagnosis and prediction of therapy responses in allergic diseases and asthma

Modern health care requires a proactive and individualized response to diseases, combining precision diagnosis and personalized treatment. Accordingly, the approach to patients with allergic diseases encompasses novel developments in the area of personalized medicine, disease phenotyping and endotyping, and the development and application of reliable biomarkers. A detailed clinical history and physical examination followed by the detection of IgE immunoreactivity against specific allergens still represents the state of the art. However, nowadays, further emphasis focuses on the optimization of diagnostic and therapeutic standards and a large number of studies have been investigating the biomarkers of allergic diseases, including asthma, atopic dermatitis, allergic rhinitis, food allergy, urticaria and anaphylaxis. Various biomarkers have been developed by omics technologies, some of which lead to a better classification of distinct phenotypes or endotypes. The introduction of biologicals to clinical practice increases the need for biomarkers for patient selection, prediction of outcomes and monitoring, to allow for an adequate choice of the duration of these costly and long‐lasting therapies. Escalating healthcare costs together with questions about the efficacy of the current management of allergic diseases require further development of a biomarker‐driven approach. Here, we review biomarkers in diagnosis and treatment of asthma, atopic dermatitis, allergic rhinitis, viral infections, chronic rhinosinusitis, food allergy, drug hypersensitivity and allergen immunotherapy with a special emphasis on specific IgE, the microbiome and the epithelial barrier. In addition, EAACI guidelines on biologicals are discussed within the perspective of biomarkers.

[Pitfalls in the diagnostics of food allergies in children and adolescents]

For the diagnostics of food allergies several points need to be considered. Firstly, it is important to recognize the various clinical pictures that can be caused by a food allergy. The assignment to a disease decides which further examinations are necessary and reasonable. In immunoglobulin (Ig) E‑mediated allergies, the detection of sensitization by determining the specific IgE or the prick test in addition to the medical history is an important mainstay of the diagnostics. Crucial is the fact that the detection of a sensitization against an extract from an allergen source only rarely implies an actual allergy. The majority of positive findings are not clinically relevant. The modern procedure of component-resolved allergy diagnostics improves the significance. Nevertheless, the diagnosis can often only be achieved by oral provocation tests. This article points out possible difficulties with the interpretation of the findings.

Food allergy severity predictions based on cellular in vitro tests

INTRODUCTION

Food allergy is increasing in prevalence and the severity of allergic reactions is unpredictable. Identifying food-allergic patients at high risk of severe reactions would allow us to offer a personalized and improved management for these patients.

AREAS COVERED

We review the evidence for using the levels of specific IgE, the nature of the allergen, and cellular tests to identify patients at high risk of developing severe allergic reactions to foods.

EXPERT OPINION

The evidence about whether the quantity of allergen-specific IgE reflects the severity of allergic reactions to foods is conflicting, with some positive and some negative studies. For some foods, specific IgE to individual components (e.g. Ara h 2 in peanut) can provide additional information. However, more important than the quantity of IgE is possibly the quality of IgE, which can be captured by individual measurements of affinity/avidity, diversity, and specific activity, but is best measured overall using the basophil and mast cell activation tests, which assess the function of IgE in its ability to induce cell activation, degranulation, and mediator release. Biomarkers look at a single aspect of the allergic response and should be interpreted in the broader clinical context for each individual patient assessed.

The Journal of Allergy and Clinical Immunology: In Practice 2019 Highlights

This article provides highlights of the clinically impactful original studies and reviews published in The Journal of Allergy and Clinical Immunology: In Practice in 2019 on the subjects of anaphylaxis, asthma, dermatitis, drug allergy, food allergy, immunodeficiency, immunotherapy, rhinitis/sinusitis, and urticaria/angioedema/mast cell disorders. Within each topic, practical aspects of diagnosis and management are emphasized. Treatments discussed include lifestyle modifications, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We designed this review to help readers consolidate and use this extensive and practical knowledge for the benefit of their patients.