Sesame allergy threshold dose distribution

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.

Smartphone-integrated fluorescent quenching immunochromatographic test strips designed for the determination of sesame allergens in food samples

A highly sensitive smartphone-integrated fluorescence quenching immunochromatographic assay (FQICA) for the detection of sesame allergen was proposed. Sesame antibodies were adsorbed on the surface of the gold nanoparticles to form fluorescent acceptors (AuNPs-Ab). Ovalbumin (OVA) protein was labeled with quantum dots (QDs) to form signal probes (QDs-OVA), which were coated on the C-line of the assay strips. A mixture of QDs-OVA and sesame protein was coated on the T-line of the strip. For FQICA, the concentration of the analyte was positively correlated with the fluorescence signal. The developed FQICA had high sensitivity for the detection of sesame protein, and its visual LOD was 80 μg/L and the quantitative LOD was 40 μg/L. In addition, the method had high specificity, except for a small cross-reaction between sesame and walnut. The visual LODs in bread, ham, and biscuits were 640 μg/L. The quantitative LODs were 320 μg/L for biscuits and 640 μg/L for bread and ham. Comparing the developed FQICA with a commercial ELISA kit, the recoveries of sesame protein in both methods were between 80% and 120%.

Sesame allergy: mechanisms, prevalence, allergens, residue detection, effects of processing and cross-reactivity

Sesame allergy is a serious public health problem and is mainly induced by IgE-mediated reactions, whose prevalence is distributed all over the world. Sesame has been included on the priority allergic food list in many countries. This review summarizes the mechanism and prevalence of sesame allergy. The characteristics, structures and epitopes of sesame allergens (Ses i 1 to Ses i 7) are included. Moreover, the detection methods for sesame allergens are evaluated, including nucleic-acid, immunoassays, mass spectrometry, and biosensors. Various processing techniques for reducing sesame allergenicity are discussed. Additionally, the potential cross-reactivity of sesame with other plant foods is assessed. It is found that the allergenicity of sesame is related to the structures and epitopes of sesame allergens. Immunoassays and mass spectrometry are the major analytical tools for detecting and quantifying sesame allergens in food. Limited technologies have been successfully used to reduce the antigenicity of sesame, involving microwave heating, high hydrostatic pressure, salt and pH treatment. More technologies for reducing the allergenicity of sesame should be widely investigated in future studies. The reduction of allergenicity in processed sesames should be ultimately confirmed by clinical studies. What's more, sesame may exhibit cross-reactivity with peanut and tree nuts.

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.

Sesame as an allergen in Lebanese food products: Occurrence, consumption and quantitative risk assessment

Despite the intensive use of sesame in the Middle Eastern diet, studies on this allergen in this region are lacking. A survey on the occurrence of sesame in Lebanese food products that did not contain this allergen as an ingredient, a food consumption survey conducted in Beirut schools, and the most recent sesame eliciting dose estimates were used to build a probabilistic risk assessment model providing estimates of sesame-induced allergic reactions per eating occasion and per week in Lebanese children and adolescents. Of 1270 food samples analysed, 34% contained sesame proteins (0.44-3392 mg kg^-1). Sesame was detected in 47% of unlabeled bulk samples, 43% of samples with PAL, and 27% of samples without PAL. "Sfouf" had the highest concentration of sesame proteins (mean 549 mg kg^-1), highest mean exposure per eating occasion (78 mg sesame proteins for children and 103 mg sesame proteins for adolescents), and posed the highest predicted risk per eating occasion (>20%) and per week (>13% individuals predicted in simulation experience at least 1 reaction). Bakery products (notably "sfouf") may pose a serious risk to sesame-allergic children and adolescents in Lebanon. Enhanced guidance on the use of PAL is needed to better protect allergic consumers.

Bayesian Stacked Parametric Survival with Frailty Components and Interval-Censored Failure Times: An Application to Food Allergy Risk

To better understand the risk of exposure to food allergens, food challenge studies are designed to slowly increase the dose of an allergen delivered to allergic individuals until an objective reaction occurs. These dose-to-failure studies are used to determine acceptable intake levels and are analyzed using parametric failure time models. Though these models can provide estimates of the survival curve and risk, their parametric form may misrepresent the survival function for doses of interest. Different models that describe the data similarly may produce different dose-to-failure estimates. Motivated by predictive inference, we developed a Bayesian approach to combine survival estimates based on posterior predictive stacking, where the weights are formed to maximize posterior predictive accuracy. The approach defines a model space that is much larger than traditional parametric failure time modeling approaches. In our case, we use the approach to include random effects accounting for frailty components. The methodology is investigated in simulation, and is used to estimate allergic population eliciting doses for multiple food allergens.

Prevalence and Severity of Sesame Allergy in the United States

IMPORTANCE

Sesame allergy is of growing concern in the United States. The US Food and Drug Administration recently issued a request for epidemiological data on the prevalence and severity of sesame allergies in the United States to inform possible regulatory action requiring sesame to be labeled as an allergen on packaged foods.

OBJECTIVE

To provide current estimates of the prevalence, severity, distribution, and clinical characteristics of sesame allergy in the United States.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study assessed findings of web- and telephone-based food allergy questionnaires. Study participants were first recruited from NORC (National Opinion Research Center) at the University of Chicago's probability-based AmeriSpeak panel, and additional participants were recruited through Survey Sampling International. Surveys were administered to a nationally representative sample of 51 819 US households from October 1, 2015, through September 31, 2016. Responses for 40 453 adults and 38 408 children were included in the analysis. Data were analyzed from January 1, 2017, through May 1, 2019.

EXPOSURES

Demographic and allergic characteristics of participants.

MAIN OUTCOMES AND MEASURES

Self-reported sesame allergy was the main outcome and was considered convincing if reported symptoms to sesame-allergic reactions were consistent with an IgE-mediated reaction. Diagnostic history of specific allergens and use of food allergy-related health care services were also primary outcomes.

RESULTS

Using survey responses from 78 851 individuals, an estimated 0.49% (95% CI, 0.40%-0.58%) of the US population reported a current sesame allergy, whereas 0.23% (95% CI, 0.19%-0.28%) met symptom-report criteria for convincing IgE-mediated allergy. An additional 0.11% (95% CI, 0.08%-0.16%) had a sesame allergy reported as physician diagnosed but did not report reactions fulfilling survey-specified convincing reaction symptoms. Among individuals with convincing IgE-mediated sesame allergy, an estimated 23.6% (95% CI, 16.9%-32.0%) to 37.2% (95% CI, 29.2%-45.9%) had previously experienced a severe sesame-allergic reaction, depending on the definition used, and 81.6% (95% CI, 71.0%-88.9%) of patients with convincing sesame allergy had at least 1 additional convincing food allergy. Roughly one-third of patients with convincing sesame allergy (33.7%; 95% CI, 26.3%-42.0%) reported previous epinephrine use for sesame allergy treatment.

CONCLUSIONS AND RELEVANCE

These data indicate a substantial burden of sesame allergy and provide valuable context to physicians and policy makers in their efforts to evaluate and reduce the public health burden of sesame allergy. Moreover, the relatively low rates of physician diagnosis observed among individuals with convincing IgE-mediated sesame allergy seem to indicate the need for clear diagnosis and appropriate management.

Sesame allergy: current perspectives

Sesame is an important global allergen affecting ~0.1% of the North American population. It is a major cause of anaphylaxis in the Middle East and is the third most common food allergen in Israel. We conducted a systematic review of original articles published in the last 10 years regarding the diagnosis and management of sesame allergy. Skin prick testing appears to be a useful predictor of sesame allergy in infants, although data are less consistent in older children and adults. The diagnostic capacity of serum-specific immunoglobulin E is poor, especially in studies that used oral food challenges to confirm the diagnosis. Double-blind, placebo-controlled food challenge thus remains the diagnostic gold standard for sesame allergy. The cornerstone of sesame allergy management is allergen avoidance, though accidental exposures are common and patients must be prepared to treat the consequent reactions with epinephrine. Novel diagnostic and treatment options such as component-resolved diagnostics, basophil activation testing, and oral immunotherapy are under development but are not ready for mainstream clinical application.

Sandwich Enzyme-Linked Immunosorbent Assay for Detecting Sesame Seed in Foods

Small amounts of sesame can trigger allergic reactions in sesame-allergic patients. Because sesame is a widely used food ingredient, analytical methods are needed to support quality control and food safety programs in the food industry. In this study, polyclonal antibodies against sesame seed proteins were raised, and an enzyme-linked immunosorbent assay (ELISA) was developed for the detection and quantification of sesame seed residue in food. A comparison was made between this ELISA and other assays, particularly focusing on recovery of sesame seed residue from different food matrices. The developed ELISA is sensitive with a lower limit of quantification of 0.5 ppm and shows essentially no cross-reactivity with other foods or food ingredients (92 tested). The ELISA has a good recovery for analyzing sesame-based tahini in peanut butter, outperforming one other test. In a baked bread matrix, the ELISA has a low recovery, while two other assays perform better. We conclude that a sensitive and specific ELISA can be constructed based on polyclonal antibodies, which is suitable for detection of small amounts of sesame seed relevant for highly allergic patients. Furthermore, we conclude that different food products may require different assays to ensure adequate quantification of sesame.