Evaluation of the basophil activation test and skin prick testing for the diagnosis of sesame food allergy

Basophil activation test in the food allergy clinic: its current use and future applications

INTRODUCTION

The basophil activation test (BAT) has shown evidence of high sensitivity and high specificity to support the diagnosis of IgE-mediated allergy. It is a functional test that uses live cells analyzed by flow cytometry and thus needs to be performed within 24h of blood collection. BAT has shown to be reproducible and reliable when tested in a clinical diagnostic laboratory with standardized protocols and flow cytometry settings.

AREAS COVERED

In this review, we summarize the evidence to support clinical use of BAT and the next steps required for clinical implementation for an improve clinical care for patients with suspected IgE-mediated food allergy.

EXPERT OPINION

BAT has recently been included in Clinical Guidelines of Food Allergy Diagnosis and its implementation in clinical practice depends largely on availability. Proposed clinical applications of the BAT include: distinction between food allergy and asymptomatic IgE sensitization; determination of food allergic status to peanut, tree nuts and seeds in polysensitized children; evaluation of tolerance to baked egg and baked milk in egg and milk allergic children; identification of patients at high-risk of severe allergic reactions; monitoring for spontaneous resolution of food allergy; confirmation of eligibility for specific treatments of food allergy; prediction and monitoring of response to immunomodulatory treatments.

Buckwheat Allergy in Asia

PURPOSE OF REVIEW

Buckwheat (BW) allergy is a significant issue in Asia. This review delves into three types of BW allergy: immediate food allergy; food-dependent, exercise-induced anaphylaxis (FDEIA) as a subset of immediate food allergy; and food protein-induced enterocolitis syndrome (FPIES); by comparing data from Asian and non-Asian countries.

RECENT FINDINGS

Most studies on BW have been published in Japan and Korea, and only a few studies on the topic have been done outside Asia. To date, seven components of common BW (Fagopyrum esculentum) and four components of Tartary BW (Fagopyrum tartaricum) have been implicated in BW allergy. Although BW-sIgE has limited utility for evaluating immediate BW allergy, Fag e 3-specific IgE, one of the components of common BW, and the skin prick test are diagnostically useful. The present review aims to shed light on the current state of knowledge, highlight research gaps, and suggest future directions in the management and understanding of BW allergy.

Validation of the NUT CRACKER Diagnostic Algorithm and Prediction for Cashew and Pistachio Co-Allergy

BACKGROUND

Because of the high cross-sensitization among tree nuts, the NUT CRACKER (Nut Co-reactivity-Acquiring Knowledge for Elimination Recommendations) study proposed a diagnostic algorithm to minimize the number of required oral food challenges (OFCs).

OBJECTIVE

To validate the algorithm for cashew and pistachio allergy and determine markers for allergic severity.

METHODS

Patients (n = 125) with a median age of 7.8 (interquartile range, 5.9-11.2) years with suspected tree nut allergy were evaluated prospectively with decision tree points on the basis of skin prick test (SPT), basophil activation test (BAT), and knowledge of the coincidence of allergies. Validation of allergic status was determined by OFC. Markers of clinical severity were evaluated using the combined original and prospective cohort (n = 187) in relationship to SPT, BAT, and Ana o 3-sIgE.

RESULTS

Reactivity to cashew in SPT, BAT, and Ana o 3-sIgE and the incidence of abdominal pain on challenge were significantly higher in dual-allergic cashew/pistachio patients (n = 82) versus single cashew allergic patients (n = 18) (P = .001). All 3 diagnostic tests showed significant inverse correlation with log10 reaction doses for positive cashew OFC. The algorithm reduced overall the total number of OFCs by 72.0%, with a positive predictive value and negative predictive value of 93.0% and 99.0%, respectively. Cashew false-positives were observed primarily in hazelnut-allergic patients (P = .026). In this population, Ana o 3-specific IgE could diagnose cashew allergy with a sensitivity of more than 90% and a specificity of more than 95%.

CONCLUSIONS

The NUT CRACKER diagnostic algorithm was validated and reduced the number of diagnostic OFCs required. Markers for severity phenotypes may guide oral immunotherapy protocols, improving the risk/benefit ratio for patients.

Comprehensive Diagnosis, Management, and Treatment of Sesame Allergy

Sesame allergy prevalence varies regionally and by age, in the range of 0.1% to 0.9%. Reactions can be severe and potentially fatal. Resolution rates are in the range of 20% to 50%. The diagnosis requires a careful history and the use of tests, such as skin prick tests and serum sesame-specific IgE. The availability of serum IgE testing for the sesame protein Ses i 1 has improved diagnostic accuracy. The emerging potential for sesame basophil activation tests and additional new tests will likely improve diagnosis in coming years, further reducing the need for diagnostic oral food challenges. Although sesame proteins share homology with those in many foods, clinically relevant cross-reactivity appears uncommon. Nevertheless, sesame is a prominent allergen for those with multiple food allergies. Management may include strict avoidance, but sesame products vary dramatically in protein content. Many people with sesame allergy tolerate forms that are low in protein, such as scattered seeds, rather than sesame paste that is protein-dense. Thus, options in the approach to avoidance are possible. Studies suggest that sesame oral immunotherapy may be safe and effective, and this and additional treatment options are emerging. Here, we review the current comprehensive diagnosis, management, and treatment for sesame allergy.

A comprehensive review on mango allergy: Clinical relevance, causative allergens, cross-reactivity, influence of processing techniques, and management strategies

Mangoes (Mangifera indica) are widely prized for their abundant nutritional content and variety of beneficial bioactive compounds and are popularly utilized in various foods, pharmaceuticals, and cosmetics industries. However, it is important to note that certain proteins present in mango can trigger various allergic reactions, ranging from mild oral allergy syndrome to severe life-threatening anaphylaxis. The immunoglobulin E-mediated hypersensitivity of mango is mainly associated with three major allergenic proteins: Man i 1 (class IV chitinase), Man i 2 (pathogenesis-related-10 protein; Bet v 1-related protein), and Man i 4 (profilin). Food processing techniques can significantly affect the structure of mango allergens, reducing their potential to cause allergies. However, it is worth mentioning that complete elimination of mango allergen immunoreactivity has not been achieved. The protection of individuals sensitized to mango should be carefully managed through an avoidance diet, immediate medical care, and long-term oral immunotherapy. This review covers various aspects related to mango allergy, including prevalence, pathogenesis, symptoms, and diagnosis. Furthermore, the characterization of mango allergens and their potential cross-reactivity with other fruits, vegetables, plant pollen, and seeds were discussed. The review also highlights the effects of food processing on mango and emphasizes the available strategies for managing mango allergy.

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.

Sesame eliciting and safe doses in a large sesame allergic population

BACKGROUND

Sesame is a significant food allergen causing severe and even fatal reactions. Given its increasing prevalence in western diet, sesame is listed as an allergenic food requiring labeling in the United States and EU. However, data on the population reaction doses to sesame are limited.

METHODS

All sesame oral food challenges (OFCs), performed either for diagnosis or for threshold identification before the beginning of sesame oral immunotherapy (OIT) between November 2011 and July 2021 in Shamir medical center were analyzed for reaction threshold distribution. Safe-dose challenges with 90-120 min intervals were also analyzed.

RESULTS

Two hundred and fifty patients underwent 338 positive OFCs, and additional 158 safe-dose OFCs were performed. The discrete and cumulative protein amounts estimated to elicit an objective reaction in 1% (ED01) of the entire cohort (n = 250) were 0.8 mg (range 0.3-6.3) and 0.7 mg (range 0.1-7.1), respectively, and those for 5% of the population (ED05) were 3.4 mg (range 1.2-20.6) and 4.5 mg (range 1.2-28.8), respectively. Safe-dose OFCs showed similar values of ED01 (0.8, 0.4-7.5 mg) and ED05 (3.4, 1.2-22.9 mg). While doses of ≤1 mg sesame protein elicited oral pruritus in 11.6% of the patients, no objective reaction was documented to this amount in any of the challenges, including safe-dose OFCs.

CONCLUSIONS

This study provides data on sesame reaction threshold distribution in the largest population of allergic patients studied, with no right or left censored data, and with validation using a safe-dose OFC. It further supports the current methods for ED determination as appropriate for establishing safety precautions for the food industry.

The future of food allergy: Challenging existing paradigms of clinical practice

The field of food allergy has seen tremendous change over the past 5-10 years with seminal studies redefining our approach to prevention and management and novel testing modalities in the horizon. Early introduction of allergenic foods is now recommended, challenging the previous paradigm of restrictive avoidance. The management of food allergy has shifted from a passive avoidance approach to active interventions that aim to provide protection from accidental exposures, decrease allergic reaction severity and improve the quality of life of food-allergic patients and their families. Additionally, novel diagnostic tools are making their way into clinical practice with the goal to reduce the need for food challenges and assist physicians in the-often complex-diagnostic process. With all the new developments and available choices for diagnosis, prevention and therapy, shared decision-making has become a key part of medical consultation, enabling patients to make the right choice for them, based on their values and preferences. Communication with patients has also become more complex over time, as patients are seeking advice online and through social media, but the information found online may be outdated, incorrect, or lacking in context. The role of the allergist has evolved to embrace all the above exciting developments and provide patients with the optimal care that fits their needs. In this review, we discuss recent developments as well as the evolution of the field of food allergy in the next decade.

Characteristics of patients diagnosed as non-allergic following food allergy oral immunotherapy referral

BACKGROUND

Ascribing food allergy diagnosis to patients who are not allergic is well described, but its implications on oral immunotherapy (OIT) have not been studied. The aim was to study non-allergic patients referred for OIT.

METHODS

All patients who began OIT at Shamir Medical Center between November 2015 and August 2020 were included. Medical records were reviewed, and skin prick tests (SPT) and/or specific IgE were measured. Patients were challenged to the index food. Allergic and non-allergic patients were compared.

RESULTS

A total of 1073 patients were studied (milk, n = 327; egg, n = 41; peanut, n = 272; sesame, n = 130; and tree nuts, n = 303) and 87 (8.1%) were found non-allergic (milk, n = 21; egg, n = 6; sesame, n = 5; peanut, n = 29; tree nuts, n = 26). Predictors of being not allergic were no previous reaction to the index food (OR = 3.3, p = 0.001), not having asthma (OR = 2.4, p = 0.001), or HDM sensitization (OR = 2.0, p = 0.007), male sex (OR = 2.3, p = 0.004), and a smaller SPT wheal size (OR = 1.5, p < 0.001).

CONCLUSIONS

A substantial number of patients referred for OIT are mislabeled with food allergy, suffer from unjustly food limitations and impairments in quality of life, and "take up" OIT places of true allergic patients. Awareness of OIT centers to this phenomenon is important.

IMPACT

A significant number (8.1%) of patients referred for OIT are found not allergic to the food they intended to treat. This study characterizes non-allergic patients referred for OIT (a lack of previous reaction to the index food, a smaller or negative SPT wheal size, and less atopic co-morbidities) and discusses the implications of such referrals. Increased awareness by OIT centers to potential non-allergic patients referred for OIT is required, including screening of patients before treatment initiation, to minimize unnecessary treatments of non-allergic patients.

Open sesame: Shedding light on an emerging global allergen

BACKGROUND

Sesame allergy has been characterized in the Middle East for some time. However, it has become more widely recognized as foods containing sesame and sesame seeds have become increasingly available in Australia, Europe, and North America. With the passage of the Food Allergy Safety, Treatment, Education, and Research Act in 2021, the United States will join other countries in identifying sesame as a major food allergen and require sesame to be labeled as a food allergen beginning in 2023.

OBJECTIVE

To review the literature related to sesame allergy as an increasingly recognized food allergen around the world.

DATA SOURCES

English-language articles retrieved by PubMed searches with relevance to sesame allergy.

STUDY SELECTIONS

Articles were included using the search terms "sesame allergy" and "sesame seed allergy."

RESULTS

A total of 69 relevant articles regarding sesame allergy, relating to its prevalence, clinical presentation, natural history, allergenic epitopes, diagnosis, and treatment, were selected.

CONCLUSION

In recent decades, considerable gains have been made in determining prevalence and natural history of sesame allergy. With increased recognition and prevalence come the need for reliable methods of identification of sesame allergy and approaches for management.

Sesame as a source of food allergens: clinical relevance, molecular characterization, cross-reactivity, stability toward processing and detection strategies

Sesame is an allergenic food with an increasing allergy prevalence among the European/USA population. Sesame allergy is generally life-persisting, being the cause of severe/systemic adverse immune responses in sesame-allergic individuals. Herein, clinical data about sesame allergy, including prevalence, diagnosis, relevance, and treatments are described, with focus on the molecular characterization of sesame allergens, their cross-reactivity and co-sensitization phenomena. The influence of food processing and digestibility on the stability/immunoreactivity of sesame allergens is critically discussed and the analytical approaches available for their detection in foodstuffs. Cross-reactivity between sesame and tree nuts or peanuts is frequent because of the high similarities among proteins of the same family. However, cross-reactivity phenomena are not always correlated with true clinical allergy in sensitized patients. Data suggest that sesame allergens are resistant to heat treatments and digestibility, with little effect on their immunoreactivity. Nevertheless, data are scarce, evidencing the need for more research to understand the effect of food processing on sesame allergenicity modulation. The demands for identifying trace amounts of sesame in foods have prompted the development of analytical methods, which have targeted both protein and DNA markers, providing reliable, specific, and sensitive tools, crucial for the effective management of sesame as an allergenic food.

Cashew oral immunotherapy for desensitizing cashew-pistachio allergy (NUT CRACKER study)

BACKGROUND

Oral immunotherapy (OIT) is a treatment option for patients with milk, egg, and peanut allergy, but data on the efficacy and safety of cashew OIT are limited.

METHODS

A cohort of 50 cashew-allergic patients aged ≥4 years, who were consecutively enrolled into cashew OIT (target dose 4000 mg protein) between 4/2016 and 12/2019. Fifteen cashew-allergic patients who continued cashew elimination served as observational controls. Co-allergy to pistachio and walnut was determined. Full desensitization rate and associated immunological changes in both groups were compared. Patients fully desensitized to cashew were instructed to consume a dose of 1200 mg cashew protein for 6 months and were then challenged to a full dose. Patients with co-allergy to pistachio or walnut were challenged to the respective nut.

RESULTS

Forty-four of 50 OIT-treated patients (88%) compared to 0% in controls tolerated a dose of 4000 mg cashew protein at the end of the study (odds ratio 8.3, 95% CI 3.9-17.7, p < 0.001). An additional three patients were desensitized to 1200 mg cashew protein, and three patients stopped treatment. Three patients (6%) were treated with injectable epinephrine for home reactions. Desensitized patients had decreased SPT, sIgE, basophil reactivity, and increased sIgG4, following treatment. Following cashew desensitization, all pistachio (n = 35) and four of eight walnut co-allergic patients were cross-desensitized to the respective nut. All (n = 44) patients consuming a low cashew dose for ≥6 months following desensitization passed a full-dose cashew OFC.

CONCLUSIONS

Cashew OIT desensitizes most cashew-allergic patients and cross-desensitizes to pistachio. Safety is similar to OIT for other foods.

IgE-Mediated food allergy: Current diagnostic modalities and novel biomarkers with robust potential

Food allergy (FA) is a serious public health issue afflicting millions of people globally, with an estimated prevalence ranging from 1-10%. Management of FA is challenging due to overly restrictive diets and the lack of diagnostic approaches with high accuracy and prediction. Although measurement of serum-specific antibodies combined with patient medical history and skin prick test is a useful diagnostic tool, it is still an imprecise predictor of clinical reactivity with a high false-positive rate. The double-blind placebo-controlled food challenge represents the gold standard for FA diagnosis; however, it requires large healthcare and involves the risk of acute onset of allergic reactions. Improvement in our understanding of the molecular mechanism underlying allergic disease pathology, development of omics-based methods, and advances in bioinformatics have boosted the generation of a number of robust diagnostic biomarkers of FA. In this review, we discuss how traditional diagnostic modalities guide appropriate diagnosis and management of FA in clinical practice, as well as uncover the potential of the latest biomarkers for the diagnosis, monitoring, and prediction of FA. We also raise perspectives for precise and targeted medical intervention to fill the gap in the diagnosis of FA.

Characteristics of patients with spontaneous resolution of sesame allergy

BACKGROUND

The prevalence of sesame allergy is increasing; strict avoidance is the mainstay of therapy. Lately, sesame oral immunotherapy was presented as an alternative treatment, with a high rate of success. Therefore, data on the natural history and the clinical characteristics of patients with persistent sesame allergy are important for the management of patients with sesame allergy.

OBJECTIVE

To describe the natural history of patients with sesame allergy and the clinical characteristics of patients with spontaneous resolution of sesame allergy compared with patients with persistent sesame allergy.

METHODS

In our retrospective study, electronic health records of patients with sesame allergy diagnosis were reviewed for demographic and clinical data. Statistical analysis of clinical characteristics of patients with spontaneous resolution compared with persistent sesame allergy was performed.

RESULTS

A total of 190 patients with sesame allergy were followed for 3.86 ±4.43 years. Of these patients, 61 (32.1%) had spontaneous resolution of sesame allergy. Patients with mild, early (before the age of 10 months) first sesame allergic reaction, with smaller than 7-mm skin prick test and without concomitant tree nut allergy had better resolution rate (56.1%).

CONCLUSION

Sesame allergy spontaneously resolved in approximately one-third of our patients and in more than half of the patients with mild first reaction (grade 1) at a young age (<10 months), with small skin prick test (<7 mm) and no concomitant tree nut allergy. Larger prospective studies with longer follow-up period are needed to better characterize the sesame allergic patients with persistent allergy who may need oral immunotherapy.

Protocol for a systematic review of the diagnostic test accuracy of tests for IgE-mediated food allergy

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of updating the guidelines on the diagnosis and management of food allergy. The existing guidelines are based on a systematic review of the literature until 30 September 2012. Therefore, a new systematic review must be undertaken to inform the new guidelines. This systematic review aims to assess the accuracy of index tests to support the diagnosis of IgE-mediated food allergy.

METHODS

The databases Cochrane CENTRAL (Trials), MEDLINE (OVID) and Embase (OVID) will be searched for diagnostic test accuracy studies from 1 October 2012 to 30 June 2021. Inclusion and exclusion criteria will be used to select appropriate studies. Data from these studies will be extracted and tabulated, and then reviewed for risk of bias and applicability using the QUADAS-2 tool. All evaluations will be done in duplicate. Studies with a high risk of bias and low applicability will be excluded. Meta-analysis will be performed if there are three or more studies of the same index test and food.

RESULTS

A protocol for the systematic review and meta-analyses is presented and was registered using Prospero prior to commencing the literature search.

DISCUSSION

Oral food challenges are the reference standard for diagnosis but involve considerable risks and resources. This protocol for systematic review aims to assess the accuracy of various tests to diagnose food allergy, which can be useful in both clinical and research settings.

Diagnostic utility of the basophil activation test in natto-induced hypersensitivity

BACKGROUND

Natto (fermented soybeans)-induced hypersensitivity is characterized by delayed symptom onset that hampers diagnosis. We aimed to clarify the clinical utility of the basophil activation test (BAT) in the diagnosis of natto-induced hypersensitivity.

METHODS

Five patients with a history of anaphylaxis and chronic urticaria suspected of natto-induced hypersensitivity and seven with chronic spontaneous urticaria clinically unrelated to natto were enrolled in the patient and control groups, respectively. The BAT was performed with two incubation times, 15 min and 1 h, in combination with various concentrations of natto-mucilage extract.

RESULTS

In controls, CD203c levels in basophils remained low in the 15-min incubation but were significantly increased in the 1-h incubation. In the patient group, in the 15-min condition, basophil CD203c was significantly upregulated by natto mucilage but not by soybean vs controls (P = 0.001). Low concentrations of natto mucilage were sufficient to upregulate basophil CD203c in the anaphylaxis cases, but high concentrations were required to induce the same effect in the urticaria cases. Finally, the dose-dependent pattern of the BAT results differed significantly between the anaphylaxis and urticaria cases (P = 0.006). Thus, a strong background reaction was observed in the BAT with 1 h incubation; 15 min of incubation was sufficient to identify patients with natto-induced hypersensitivity and may distinguish the clinical phenotype of natto-induced hypersensitivity, i.e., anaphylaxis or urticaria.

CONCLUSIONS

The BAT with a 15-min incubation period is useful in diagnosing natto-induced hypersensitivity.

Innovative robust basophil activation test using a novel gating strategy reliably diagnosing allergy with full automation

BACKGROUND

Allergy is one of the most common chronic diseases in Europe. Therefore, an increased need for specific and sensitive diagnostic tests that truly detect allergy exists. This study aimed at establishing a highly specific high-throughput and automated basophil activation test (BAT) that proves the existence of an allergy with utmost probability.

METHODS

BAT from 1104 samples was analyzed; a novel gating strategy with three antibodies (FcεRIα, CD203c, CD63) was established and compared with our published protocol (12 antibodies). Based on the novel gating strategy, storage conditions, automated measurement, and analyses using R (1376 samples out of 1389) were optimized to set up a high-throughput BAT.

RESULTS

No differences in sensitivity and specificity were found between the novel three antibody (FcεRIα, CD203c, CD63) and the 12 antibody gating strategy or between automated and manually analyzed samples (saving up to 90% of labor time). The time frame for basophil activation measurement after blood donation has been extended considerably (whole blood storage ≤7 days (RT) and 17 days (4°C) prior to BAT preparation and measurement). Respective storage conditions were optimized for samples after stimulation, staining, and preparation (≤7 days (RT) and 28 days (4°C)). These achievements were confirmed by a nationwide ring trial showing robustness and applicability of our BAT on a variety of flow cytometers.

CONCLUSION

Our considerable optimizations overcame the hurdles that until now prevented the BAT from being used as high-throughput allergy diagnostic test in routine laboratories and shall allow for collaborative studies between clinics and research centers.

Combinatorial advantage of Ses i 1-specific IgE and basophil activation for diagnosis of sesame food allergy

BACKGROUND

The prevalence of sesame food allergy (SFA) is increasing worldwide with the potential of anaphylactic reactions upon exposure. Utility of specific component IgE testing as an alternative to the oral food challenge (OFC), the diagnostic standard, is being investigated.

METHODS

Patients (n = 42) with suspected SFA completed an open OFC to sesame. Diagnostic testing included serum levels of Ses i 1-specific IgE, skin prick test with high-protein extract, and basophil reactivity (% induced CD63 expression) for each patient. The diagnostic utility of these tests was evaluated at a 95% sensitivity, with the outcome measure being the number of OFCs required.

RESULTS

Twenty-seven patients (64%) were diagnosed with SFA. Ses i 1 IgE differed significantly between allergic and tolerant patients (p = .0001). ROC curve analysis for Ses i 1 IgE yielded an AUC of 0.88 ± 0.05. Levels of Ses i 1 IgE correlated to induced CD63+ expression on basophils (p = .0001). Ses i 1 IgE was not sufficiently robust as a single step for diagnosis. Used concurrently, BAT and Ses i 1 IgE yielded correct positive classifications for 25 of 27 sesame-allergic patients with two false positives (93% PPV). Both tests were negative in 5 non-allergic patients. Patients with divergent Ses i 1 IgE and BAT results required OFC (n = 10, 24% of patients). Alternatively, sequential use of BAT, ruling in SFA followed by Ses i 1 IgE diagnosing non-allergic patients, yielded a 89% PPV, with 19% requiring OFC.

CONCLUSION

Ses i 1 IgE and BAT used together can decrease the need for OFC in most SFA patients. A prospective cohort trial is necessary to validate these results.

Bringing the Next Generation of Food Allergy Diagnostics into the Clinic

Food allergy diagnosis has a massive impact on the lives of patients and their families. Despite recent developments with specific IgE to component allergens, a significant proportion of patients assessed for possible food allergy require oral food challenge to ensure an accurate diagnosis. More precise diagnostic methods are required to reduce the need for oral food challenges. Bead-based epitope assays and cellular tests, such as basophil activation and mast cell tests are the most novel and promising tests on the horizon. There is a pathway to pursue to enable their incorporation in clinical practice, including standardization, technical validation, clinical validation, external validation, overcoming practical and logistical issues, and regulatory approval. Valuable clinical application of these tests goes beyond diagnosis and includes risk assessment to identify allergic patients who are most sensitive and at risk for severe allergic reactions, and to define prognosis and assess clinical response to immunomodulatory treatments.

Assessment of Allergic and Anaphylactic Reactions to mRNA COVID-19 Vaccines With Confirmatory Testing in a US Regional Health System

IMPORTANCE

As of May 2021, more than 32 million cases of COVID-19 have been confirmed in the United States, resulting in more than 615 000 deaths. Anaphylactic reactions associated with the Food and Drug Administration (FDA)-authorized mRNA COVID-19 vaccines have been reported.

OBJECTIVE

To characterize the immunologic mechanisms underlying allergic reactions to these vaccines.

DESIGN, SETTING, AND PARTICIPANTS

This case series included 22 patients with suspected allergic reactions to mRNA COVID-19 vaccines between December 18, 2020, and January 27, 2021, at a large regional health care network. Participants were individuals who received at least 1 of the following International Statistical Classification of Diseases and Related Health Problems, Tenth Revision anaphylaxis codes: T78.2XXA, T80.52XA, T78.2XXD, or E949.9, with documentation of COVID-19 vaccination. Suspected allergy cases were identified and invited for follow-up allergy testing.

EXPOSURES

FDA-authorized mRNA COVID-19 vaccines.

MAIN OUTCOMES AND MEASURES

Allergic reactions were graded using standard definitions, including Brighton criteria. Skin prick testing was conducted to polyethylene glycol (PEG) and polysorbate 80 (P80). Histamine (1 mg/mL) and filtered saline (negative control) were used for internal validation. Basophil activation testing after stimulation for 30 minutes at 37 °C was also conducted. Concentrations of immunoglobulin (Ig) G and IgE antibodies to PEG were obtained to determine possible mechanisms.

RESULTS

Of 22 patients (20 [91%] women; mean [SD] age, 40.9 [10.3] years; 15 [68%] with clinical allergy history), 17 (77%) met Brighton anaphylaxis criteria. All reactions fully resolved. Of patients who underwent skin prick tests, 0 of 11 tested positive to PEG, 0 of 11 tested positive to P80, and 1 of 10 (10%) tested positive to the same brand of mRNA vaccine used to vaccinate that individual. Among these same participants, 10 of 11 (91%) had positive basophil activation test results to PEG and 11 of 11 (100%) had positive basophil activation test results to their administered mRNA vaccine. No PEG IgE was detected; instead, PEG IgG was found in tested individuals who had an allergy to the vaccine.

CONCLUSIONS AND RELEVANCE

Based on this case series, women and those with a history of allergic reactions appear at have an elevated risk of mRNA vaccine allergy. Immunological testing suggests non-IgE-mediated immune responses to PEG may be responsible in most individuals.

Peanut Can Be Used as a Reference Allergen for Hazard Characterization in Food Allergen Risk Management: A Rapid Evidence Assessment and Meta-Analysis

Regional and national legislation mandates the disclosure of “priority” allergens when present as an ingredient in foods, but this does not extend to the unintended presence of allergens due to shared production facilities. This has resulted in a proliferation of precautionary allergen (“may contain”) labels (PAL) that are frequently ignored by food-allergic consumers. Attempts have been made to improve allergen risk management to better inform the use of PAL, but a lack of consensus has led to variety of regulatory approaches and nonuniformity in the use of PAL by food businesses. One potential solution would be to establish internationally agreed “reference doses,” below which no PAL would be needed. However, if reference doses are to be used to inform the need for PAL, then it is essential to characterize the hazard associated with these low-level exposures. For peanut, there are now published data relating to over 3000 double-blind, placebo-controlled challenges in allergic individuals, but a similar level of evidence is lacking for other priority allergens. We present the results of a rapid evidence assessment and meta-analysis for the risk of anaphylaxis to a low-level allergen exposure for priority allergens. On the basis of this analysis, we propose that peanut can and should be considered an exemplar allergen for the hazard characterization at a low-level allergen exposure.

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.

Food allergy safety: a descriptive report of changing policy in a single large medical center

Background

Food allergy can result in life-threatening anaphylaxis and is considered an increasing public health burden. Hospitalized patients are dependent on the hospital menu to meet their nutritional needs; thus, errors in the meals provided can have a substantial impact on patients’ health outcomes. In Israel, no specific policy protocol exists to ensure food allergy safety in the setting of a hospital foodservice system.

Objectives

This paper has two aims: 1) to provide an in-depth review of food allergy as a major public health concern and 2) to report actions taken in a single large medical center, as an ongoing project that aimed to ensure patients’ safety, and which ended in developing policy on this matter.

Results

During the years 2017–2019, we initiated several interventions with the goal of achieving food allergy safety and ensuring quality of care for patients with food allergies at Hadassah Hebrew University Medical Center. These included integrating food management safety into the computerized foodservice system, highlighting labels on patients’ food trays, introducing safety checks into the process of food delivery to hospitalized patients; and ensuring the nutritional requirements of patients with allergy restrictions. Moreover, changes were made in specialized menus for patients with various types of food allergy, and specific procedures were implemented regarding enteral feeding, to prevent accidental allergen exposure. All the procedures were incorporated into a written protocol that applies to all hospital employees, and the staff received the relevant training.

Conclusions

Our experience suggests that methods for food allergy safety should be promoted, and that an established policy and suitable set of guidelines on this matter is required. This clearly mandates collaboration between the various sectors of the hospital, including management and the computer department; and the medical, nursing, dietetics and kitchen staffs. Furthermore, routine ongoing knowledge training programs for medical teams and kitchen staff are crucial for such implementational changes. In a technological world, computerized systems delivering food to hospitalized patients must be adapted such as to create a uniformly safe food environment of healthcare systems, and developing a suitable policy should be prioritized accordingly by hospitals across Israel, with collaboration and synergy between institutions management and the departments of nutrition and patient safety and risk management.

Biomarkers of diagnosis and resolution of food allergy

Food allergy is increasing in prevalence, affecting up to 10% of children in developed countries. Food allergy can significantly affect the quality of life and well-being of patients and their families; therefore, an accurate diagnosis is of extreme importance. Some food allergies can spontaneously resolve in 50%-60% of cow's milk and egg-allergic, 20% of peanut-allergic and 9% of tree nut-allergic children by school age. For that reason, food-allergic status should be monitored over time to determine when to reintroduce the food back into the child's diet. The gold-standard to confirm the diagnosis and the resolution of food allergy is an oral food challenge; however, this involves the risk of causing an acute-allergic reaction and requires clinical experience and resources to treat allergic reactions of any degree of severity. In the clinical setting, biomarkers have been used and validated to enable an accurate diagnosis when combined with the clinical history, deferring the oral food challenge, whenever possible. In this review, we cover the tools available to support the diagnosis of food allergies and to predict food allergy resolution over time. We review the latest evidence on different testing modalities and how effective they are in guiding clinical decision making in practice. We also evaluate predictive test cut-offs for the more common food allergens to try and provide guidance on when challenges might be most successful in determining oral tolerance in children.

Subjective oral symptoms are insufficient predictors of a positive oral food challenge

BACKGROUND

Subjective oral symptoms, especially if recurrent, might lead to termination of an oral food challenge (OFC) for fear of a subsequent severe reaction.

METHODS

In a single-center retrospective cohort study, oral food challenges to milk, egg, peanut, sesame, or tree nuts performed between January 2016 and January 2018 in patients aged ≥3 years, at the Institute of Allergy, Immunology and Pediatric Pulmonology in Shamir Medical Center, were analyzed. Subjective oral symptoms during the challenge were documented, and their association with the challenge outcome was examined.

RESULTS

A total of 323 patients underwent 652 oral food challenges to the investigated foods (milk, 71; egg, 22; peanut, 48; sesame, 24; and tree nuts, 487). Subjective oral symptoms were experienced in 237 (36.3%) of all OFCs performed, and their rate was comparable across most foods tested. The rate of positive challenges was significantly higher when subjective oral symptoms were experienced during the challenge than when they were not (69.6% vs 30.4%, respectively, P < .001). However, the false-positive rate of such symptoms in predicting a positive food challenge was 30.3% for all foods; peanut, 40%; sesame, 27.3%; milk, 35.5%; egg, 33%; and tree nuts, 28.4%. Overall, subjective oral symptoms (SOS) provided sensitivity of 56.7, specificity 80.4, PPV 69.6, and NPV 69.0 for predicting OFC outcome. Importantly, reactions during positive challenges with and without subjective oral symptoms were comparable to severity.

CONCLUSIONS

Continuing OFCs with subjective oral symptoms is recommended for it will prevent false-positive results in a third of cases without increasing patients' risk.

Basophil activation test in allergy diagnostics

The prevalence of allergic diseases in Poland and in the world continues to rise in recent years. The most commonly used methods for diagnosing IgE – dependent allergies are skin prick testing (SPT) and assessment of specific IgE (sIgE) directed against specific allergens. However, both methods have some disadvantages and the obtained results may be inconsistent. In particular, routine diagnostic tests are not always effective for some drugs and foods. Consequently, additional laboratory tools should be used. Basophil activation test (BAT) based on flow cytometry is a promising diagnostic method. The present paper demonstrates the usefulness and effectiveness of BAT protocols in allergy diagnosis in scientific research. In comparison to routinely used diagnostic methods, BAT is an expensive and complicated laboratory tool. However, it offers the possibility to efficiently and effectively recognize allergies. Introducing BAT into routine diagnostics in allergology is problematic because this method has not yet been standardized and validated. Therefore, there is a justified need to continue research in this field. If standardized and validated, BAT may offer a reasonable improvement in allergy diagnostics in the future.

Microbial signature in IgE-mediated food allergies

BACKGROUND

Multiple studies suggest a key role for gut microbiota in IgE-mediated food allergy (FA) development, but to date, none has studied it in the persistent state.

METHODS

To characterize the gut microbiota composition and short-chain fatty acid (SCFAs) profiles associated with major food allergy groups, we recruited 233 patients with FA including milk (N = 66), sesame (N = 38), peanut (N = 71), and tree nuts (N = 58), and non-allergic controls (N = 58). DNA was isolated from fecal samples, and 16S rRNA gene sequences were analyzed. SCFAs in stool were analyzed from patients with a single allergy (N = 84) and controls (N = 31).

RESULTS

The gut microbiota composition of allergic patients was significantly different compared to age-matched controls both in α-diversity and β-diversity. Distinct microbial signatures were noted for FA to different foods. Prevotella copri (P. copri) was the most overrepresented species in non-allergic controls. SCFAs levels were significantly higher in the non-allergic compared to the FA groups, whereas P. copri significantly correlated with all three SCFAs. We used these microbial differences to distinguish between FA patients and non-allergic healthy controls with an area under the curve of 0.90, and for the classification of FA patients according to their FA types using a supervised learning algorithm. Bacteroides and P. copri were identified as taxa potentially contributing to KEGG acetate-related pathways enriched in non-allergic compared to FA. In addition, overall pathway dissimilarities were found among different FAs.

CONCLUSIONS

Our results demonstrate a link between IgE-mediated FA and the composition and metabolic activity of the gut microbiota.

Developments in the field of clinical allergy in 2018 through the eyes of Clinical and Experimental Allergy, Part II

In this article, we describe developments in the field of clinical allergy as described by Clinical and Experimental Allergy in 2018; epidemiology, asthma and rhinitis, clinical allergy and allergens are all covered.

Cell-Based Functional IgE Assays Are Superior to Conventional Allergy Tests for Shrimp Allergy Diagnosis

BACKGROUND

The diagnosis of shellfish allergy currently relies on patient history, skin prick test (SPT), and serum specific IgE (sIgE) quantification. These methods lack sufficient diagnostic accuracy, whereas the gold standard of oral food challenges is risky and burdensome. Markers of reactivity and severity of allergic reactions to shellfish will improve clinical care of these patients.

OBJECTIVES

This study compared the diagnostic performance of SPT, sIgE, basophil activation test (BAT), and IgE crosslinking-induced luciferase expression (EXiLE) test for shrimp allergy.

METHODS

Thirty-five subjects with documented history of shrimp allergic reactions were recruited and grouped according to results of double-blind, placebo-controlled food challenge (DBPCFC). In addition to routine diagnostics, BAT (Flow CAST) and EXiLE test with shrimp extract and tropomyosin were performed.

RESULTS

Of 35 subjects, 15 were shrimp allergic with pruritus, urticaria, and itchy mouth on DBPCFC, whereas 20 were tolerant to shrimp. Tropomyosin only accounted for 53.3% of sensitization among subjects with challenge-proven shrimp allergy. BAT using shrimp extract as stimulant showed the highest area under curve value (0.88), Youden Index (0.81), likelihood ratio (14.73), odds ratio (104), and variable importance (4.27) when compared with other assays and tropomyosin diagnosis. Results of BAT significantly correlated with those of EXiLE (r = 0.664, P < .0001).

CONCLUSIONS

BAT is a more accurate diagnostic marker for shrimp allergy than SPT and shrimp sIgE, whereas the EXiLE test based on an IgE crosslinking assay is a good alternative to BAT. Tropomyosin may not be the most important shrimp allergen in Chinese, which warrants further investigation to search for other major allergens and diagnostic markers.

Basophil Activation as Marker of Clinically Relevant Allergy and Therapy Outcome

For some years now the basophil activation test (BAT) using flow cytometry has emerged as a powerful tool and sensitive marker that can be used to detect clinically relevant allergies, provide information on the severity of an allergic reaction, and monitor therapies. Compared to other in vitro diagnostic tests, BAT seems to have a better informative value in terms of clinical relevance. In general, the BAT can be used for the diagnosis of the most common forms of IgE-mediated allergy such as hymenoptera venom allergy, inhalant allergy, food allergy, and drug allergy. Various basophil markers and parameters have been established which, depending on the trigger of the respective allergy, can provide information on the clinical relevance of sensitization, on the development of natural tolerance, on trigger thresholds, and on the severity of the allergic reaction. The BAT also serves as a suitable follow-up instrument for various therapeutic approaches such as specific immunotherapy, desensitization protocols, or use of anti-IgE-antibodies for the various diseases. Quality controls for routine use, standardization, and automatization are expected to expand the range of applications for the above-mentioned indications.

Patient Characteristics and Risk Factors for Home Epinephrine-Treated Reactions During Oral Immunotherapy for Food Allergy

BACKGROUND

Oral immunotherapy (OIT) is effective in desensitizing food-allergic patients but adverse events limit its applicability.

OBJECTIVE

To identify risk factors for home epinephrine-treated reactions during the build-up phase of OIT.

METHODS

A retrospective cohort study of patients older than 3.7 years undergoing OIT for food allergy at Shamir Medical Center between April 2010 and March 2019. All patients with a final disposition of full desensitization, partial desensitization, or failure were analyzed. Risk factors and outcome of home epinephrine-treated reactions were examined.

RESULTS

A total of 1037 patients (mean age, 8.4 years) who underwent 1100 OIT treatments (milk, n = 710; peanut, n = 213; egg, n = 50; sesame, n = 57; and tree nuts, n = 70) reached a final disposition and were analyzed. Full desensitization was achieved in 763 (69.4%) treatments, partial desensitization in 219 (19.9%), and 118 (10.7%) failed. Epinephrine was administered to 121 patients (11.7%) during 10.8% of treatments. Milk OIT was a significant risk factor both for epinephrine-treated reactions (odds ratio, 2.15; 95% CI, 1.25-3.68) and for low rate of full desensitization following such reactions compared with nonmilk OIT (18.2% vs 73.9%, respectively; P < .0001). Risk factors during milk OIT included asthma, pre-OIT reaction severity, lower tolerated dose, and epinephrine-treated reactions during clinic updosing, whereas risk factors during nonmilk OIT were male sex and lower tolerated dose.

CONCLUSIONS

Milk OIT poses a significant risk for home epinephrine-treated reactions during OIT and for poor outcome following such reactions. Together with the additional risk factors described for both milk and nonmilk OIT, this information may assist in patient selection for treatment.

Efficacy and Safety of Sesame Oral Immunotherapy-A Real-World, Single-Center Study

BACKGROUND

The presence of sesame in Western diet is increasing, making its avoidance by sesame-allergic patients more challenging.

OBJECTIVE

To report the efficacy and safety of sesame oral immunotherapy (OIT).

METHODS

Sixty patients aged 4 years or older, diagnosed as sesame-allergic on the basis of a positive oral food challenge, were consecutively enrolled into OIT between November 2014 and November 2017. Fifteen patients with sesame allergy, based on a positive oral food challenge or a recent immediate reaction, and a positive skin prick test result or specific IgE, continued sesame elimination and served as observational controls. Immunologic parameters were measured in a subset (OIT, n = 16; controls, n = 11) at the start and end of the study. Fully desensitized patients continued daily consumption of 1200 mg sesame protein and challenged with 4000 mg after more than 6 months.

RESULTS

Fifty-three OIT-treated patients (88.4%) were fully desensitized to sesame, compared with 0% of controls. Four additional patients (total 57 of 60 = 95%) were desensitized to more than 1000 mg protein. Reactions occurred in 4.7% of hospital doses and 1.9% of home doses. Epinephrine-treated reactions occurred in 16.7% of patients for hospital and 8.3% for home doses. Significant decreases in rSes i 1 IgE (P = .007) and basophil reactivity (P = .001) and increases in sesame and rSes i 1 IgG₄ (P = .001) occurred in OIT-treated patients but not in controls. Forty-seven patients desensitized to 4000 mg were evaluated more than 6 months after reaching maintenance. Only mild reactions were reported during maintenance, and all passed the 4000-mg challenge.

CONCLUSIONS

Sesame-OIT is an effective alternative to sesame avoidance in allergic patients. The potential for adverse events necessitates its performance in specialized centers.