Immunoglobulin E antibody reactivity to the major shrimp allergen, tropomyosin, in unexposed Orthodox Jews

Mite allergen sensitization patterns in Turkish children: Age-related changes and molecular correlations

BACKGROUND

Mites are ubiquitous aeroallergens found worldwide. Elucidating individual mite allergen sensitization patterns provides critical insights for managing allergic diseases. This study aimed to investigate molecular allergen (MA) sensitization patterns across different age groups and explore cluster relationships among mite-sensitized children.

METHODS

We analyzed 76 children who exhibited sensitization to at least one of the 17 distinct mite MAs through microarray testing.

RESULTS

Dermatophagoides farinae exhibited a slightly higher prevalence of sensitization compared with Dermatophagoides pteronyssinus. Der p 1/2 and Der f 1/2 demonstrated an almost 40% sensitization rate, while Der p 10/Blo t 10, Der p 20, Der p 23, and Gly d 2/Lep d 2 displayed an approximately 20% sensitization rate. Sensitization levels and ratios increased significantly with age for Der p 23 but showed numerical rises for other MAs, except for Der p 10/Blo t 10. The presence of various types of atopic diseases had only a minimal impact on sensitization profiles. Strong correlations emerged between Der f 2 and Der p 2, Der p 10 and Blo t 10, Der p 21 and Blo t 5, as well as Gly d 2 and Lep d 2. Hierarchical cluster analysis substantiated these relationships. Der p 10 and its homolog Blo t 10-sensitive patients (15/76) were mostly seen as mono sensitization(12/15). Ten patients exhibited monosensitization to Der p 20, suggesting a possible association with scabies infection.

CONCLUSION

In children, mite sensitization diversity and levels increased with age. The presence of significant correlations/cluster relationships among these sensitizations underscores homologies among specific MAs.

House dust mite allergy in Malaysia: review of research gaps in the current scenario and the way forward

The prevalence of house dust mite (HDM) allergy, especially in Asian countries with rapid urbanization, has been increasing. House dust mites thrive in places with relatively high humidity. With the combination of climate change, naturally high humidity, and urbanization, tropical countries like Malaysia are becoming a hotspot for HDM allergy fast. With a previously reported sensitization rate of between 60 and 80%, it is a worrying trend for Malaysia. However, due to incomplete and out-of-date data, as seen by the limited study coverage in the past, these numbers do not paint a complete picture of the true HDM allergy scene in Malaysia. This review briefly discusses the HDM fauna, the HDM sensitization rate, the common diagnosis and therapeutic tools for HDM allergy in Malaysia, and makes suggestions for possible improvements in the future. This review also highlights the need of more comprehensive population-based prevalence studies to be done in Malaysia, encompassing the three main HDMs-Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis-as the lack of up-to-date studies failed to give a clearer picture on the current scenario of HDM allergy in Malaysia. Future studies will be beneficial to the nation in preparing a better blueprint for the management and treatment of HDM allergy.

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.

Shrimp sensitization in house dust mite algerian allergic patients: A single center experience

Background

Cross-reactivity between shrimp and house dust mite (HDM) proteins has been widely documented. However, a significant geographical variability in sensitization patterns and cross-reactive allergens has been reported which may impact the diagnosis and management of shrimp allergy among HDM-shrimp co-sensitized patients. This study aimed to investigate the prevalence of shrimp and tropomyosin sensitization among HDM-allergic patients in order to understand the local epidemiology to inform the development of targeted diagnostic and therapeutic tools.

Methods

Four hundred forty-six (446) HDM-allergic patients and 126 atopic controls were screened for shrimp-specific IgE using the IMMULITE 2000 XPI® System. HDM-shrimp sensitized subjected were also tested for IgE tropomyosin (nPen m 1) and thoroughly interviewed about their shellfish consumption habits. Tropomyosin sensitized patients were subjected to further analysis including measurement of IgE specific to squid and crab.

Results

The prevalence of shrimp sensitization in the HDM-allergic population was 20.4% vs 0% in the control group. Of them 63.7% were clinically allergic to shrimp, while 9 cases had no history of allergic reaction to this food and 24 patients reported not having consumed shrimp before. Besides, 72.5% of the HDM-shrimp sensitized subjects had tropomyosin-specific IgE with a positivity rate of 82.8% among shrimp-allergic patients. Among tropomyosin reactors, 95.5% were sensitized to crab and 89.5% to squid, none of them had previously ingested neither crab nor squid. Nevertheless, one-third of HDM-shrimp sensitized patients who never consumed shrimp before did not react to tropomyosin.

Conclusions

Shrimp allergy seems to be strictly dependent on HDM sensitization, at least in this geographical area. Therefore, HDM allergic patients should be systematically screened for shrimp sensitization and asked about the consumption of shellfish. Tropomyosin is a major and clinically relevant shrimp allergen that accounts for shellfish-HDM cross-reactivity. However, other components could be involved.

African American Children Are More Likely to Be Allergic to Shellfish and Finfish: Findings from FORWARD, a Multisite Cohort Study

BACKGROUND

Despite major differences in health profiles and rates of health care utilization between African American and White children with food allergy (FA), the detailed phenotypic variables that can potentially impact these outcomes have not been thoroughly studied.

OBJECTIVE

We aimed to characterize phenotypic differences such as allergies to different foods and allergic comorbidities between African American and White children with FA enrolled in the Food Allergy Outcomes Related to White and African American Racial Differences study.

METHODS

Our active, prospective, multicenter cohort study is currently enrolling African American and White children aged 0 to 12 years diagnosed with FA and followed by allergy/immunology clinics at 4 urban tertiary centers in the United States. To evaluate associations between race and phenotypic variables, we used multivariable logistic regression, adjusting for important demographic and confounding factors, as well as potential household clustering.

RESULTS

As of May 2020, there were 239 African Americans and 425 Whites with complete intake information enrolled in the study. In comparison with Whites, we found that African Americans had significantly higher adjusted odds of allergy to finfish (odds ratio [OR]: 2.54, P < .01) and shellfish (OR: 3.10, P < .001). African Americans also had higher adjusted odds of asthma than Whites (asthma prevalence of 60.5% in African Americans and 27.2% in Whites; OR: 2.70, P < .001). In addition, shellfish allergy was associated with asthma, after controlling for race.

CONCLUSION

Among a diverse cohort of children with physician-diagnosed FA, we observed that African American children had higher odds of allergy to shellfish and finfish, and higher rates of asthma. Interestingly, having asthma was independently associated with allergy to shellfish, after controlling for race.

Clinical Relevance of Cross-Reactivity in Food Allergy

The diagnosis and management of food allergy is complicated by an abundance of homologous, cross-reactive proteins in edible foods and aeroallergens. This results in patients having allergic sensitization (positive tests) to many biologically related foods. However, many are sensitized to foods without exhibiting clinical reactivity. Although molecular diagnostics have improved our ability to identify clinically relevant cross-reactivity, the optimal approach to patients requires an understanding of the epidemiology of clinically relevant cross-reactivity, as well as the food-specific (degree of homology, protein stability, abundance) and patient-specific factors (immune response, augmentation factors) that determine clinical relevance. Examples of food families with high rates of cross-reactivity include mammalian milks, eggs, fish, and shellfish. Low rates are noted for grains (wheat, barley, rye), and rates of cross-reactivity are variable for most other foods. This review discusses clinically relevant cross-reactivity related to the aforementioned food groups as well as seeds, legumes (including peanut, soy, chickpea, lentil, and others), tree nuts, meats, fruits and vegetables (including the lipid transfer protein syndrome), and latex. The complicating factor of addressing co-allergy, for example, the risks of allergy to both peanut and tree nuts among atopic patients, is also discussed. Considerations for an approach to individual patient care are highlighted.

Insect Allergens on the Dining Table

Edible insects are important sources of nutrition, particularly in Africa, Asia, and Latin America. Recently, edible insects have gained considerable interest as a possible solution to global exhaustion of the food supply with population growth. However, little attention has been given to the adverse reactions caused by insect consumption. Here, we provide an overview of the food allergens in edible insects and offer insights for further studies. Most of the edible insect allergens identified to date are highly cross-reactive invertebrate pan-allergens such as tropomyosin and arginine kinase. Allergic reactions to these allergens may be cross-reactions resulting from sensitization to shellfish and/or house dust mites. No unique insect allergen specifically eliciting a food allergy has been described. Many of the edible insect allergens described thus far have counterpart allergens in cockroaches, which are an important cause of respiratory allergies, but it is questionable whether inhalant allergens can cause food allergies. Greater effort is needed to characterize the allergens that are unique to edible insects so that safe edible insects can be developed. The changes in insect proteins upon food processing or cooking should also be examined to enhance our understanding of edible insect food allergies.

Occupational allergic contact urticaria to tropomyosin from squid

A cook’s mate working in an Austrian restaurant reported acutely occurring urticarial skin lesions after processing and cooking squid. The prick-to-prick test with squid showed a ++ positive urticarial reaction. Elevated specific IgE antibody levels to squid, shrimp, and house dust mites as well as to tropomyosin from shrimp and house dust mite could be detected in the ImmunoCAP. By means of immunoblot and ELISA, a reaction to squid extract as well as increased IgE antibody levels to squid and tropomyosin from squid could be detected. The patient was diagnosed with a clinically and occupationally relevant type I allergy to squid with cross-reaction to tropomyosin of other invertebrates and therefore recognized as an occupational disease.

Hypoallergenic mutants of the major oyster allergen Cra g 1 alleviate oyster tropomyosin allergenic potency

Design of hypoallergen with low IgE reactivity is desirable for allergen-specific immunotherapy. Despite oyster tropomyosin (Cra g 1) is considered as the major allergen, no immunotherapy is available now. In the current research, we generated hypoallergens of Cra g 1 and evaluated their allergenicity. Four hypoallergenic derivatives were constructed by epitope deletion or site-directed mutagenesis on grounds of the identified epitopes. They showed obvious reduction in reactivity towards IgE from oyster-allergic patients and Cra g 1-sensitized BN rats, as well as significant decrease in degranulation and secretion of allergic mediators including histamine, IL-4, IL-6 and TNF-α. In addition, to further investigate the molecular mechanism, we examined the effects of these variants on FcεRI-dependent signalling pathway in IgE-challenged RBL-2H3 cells. We found that the hypoallergenic mutants were able to attenuate FcεRI-mediated signaling cascades in tested cells. These results indicate that the hypoallergenic molecules have ideal characteristics and offer a promising new strategy in clinical immunotherapy for shellfish-allergic subjects.

The multiple roles of mite allergens in allergic diseases

PURPOSE OF REVIEW

Mites are the most worldwide spread allergens and relevant causative of respiratory allergies. Life cycle, component allergens, biological activity and immunogenicity are discussed in depth.

RECENT FINDINGS

It is now known that mite allergens are able to stimulate the innate immune system through different receptors, for example, TLRs and PARs. The activation of the cells in the airway mucosa is followed by type 2 polarizing cytokine production in predisposed individuals. This complex network plays a pivotal role into the promotion of Th2 differentiation.

SUMMARY

This is a comprehensive review regarding all the mite allergens known so far, including their location within dust mites, composition, biological activities and binding receptors relevant to the fate of the immunological response.

The Role of Dust Mites in Allergy

House dust mites are an unsurpassed cause of atopic sensitization and allergic illness throughout the world. The major allergenic dust mites Dermatophagoides pteronyssinus, Dermatophagoides farinae, Euroglyphus maynei, and Blomia tropicalis are eight-legged members of the Arachnid class. Their approximately 3-month lifespan comprises egg, larval, protonymph, tritonymph, and adult stages, with adults, about one fourth to one third of a millimeter in size, being at the threshold of visibility. The geographic and seasonal distributions of dust mites are determined by their need for adequate humidity, while their distribution within substrates is further determined by their avoidance of light. By contacting the epithelium of the eyes, nose, lower airways, skin, and gut, the allergen-containing particles of dust mites can induce sensitization and atopic symptoms in those organs. Various mite allergens, contained primarily in mite fecal particles but also in shed mite exoskeletons and decaying mite body fragments, have properties that include proteolytic activity, homology with the lipopolysaccharide-binding component of Toll-like receptor 4, homology with other invertebrate tropomyosins, and chitin-cleaving and chitin-binding activity. Mite proteases have direct epithelial effects including the breaching of tight junctions and the stimulation of protease-activated receptors, the latter inducing pruritus, epithelial dysfunction, and cytokine release. Other components, including chitin, unmethylated mite and bacterial DNA, and endotoxin, activate pattern recognition receptors of the innate immune system and act as adjuvants promoting sensitization to mite and other allergens. Clinical conditions resulting from mite sensitization and exposure include rhinitis, sinusitis, conjunctivitis, asthma, and atopic dermatitis. Systemic allergy symptoms can also occur from the ingestion of cross-reacting invertebrates, such as shrimp or snail, or from the accidental ingestion of mite-contaminated foods. Beyond their direct importance as a major allergen source, an understanding of dust mites leads to insights into the nature of atopy and of allergic sensitization in general.

Conservation Analysis of B-Cell Allergen Epitopes to Predict Clinical Cross-Reactivity Between Shellfish and Inhalant Invertebrate Allergens

Understanding and predicting an individual's clinical cross-reactivity to related allergens is a key to better management, treatment and progression of novel therapeutics for food allergy. In food allergy, clinical cross-reactivity is observed in patients reacting to unexpected allergen sources containing the same allergenic protein or antibody binding patches (epitopes), often resulting in severe allergic reactions. Shellfish allergy affects up to 2% of the world population and persists for life in most patients. The diagnosis of shellfish allergy is however often challenging due to reported clinical cross-reactivity to other invertebrates including mites and cockroaches. Prediction of cross-reactivity can be achieved utilizing an in-depth analysis of a few selected IgE-antibody binding epitopes. We combined available experimentally proven IgE-binding epitopes with informatics-based cross-reactivity prediction modeling to assist in the identification of clinical cross-reactive biomarkers on shellfish allergens. This knowledge can be translated into prevention and treatment of allergic diseases. To overcome the problem of predicting IgE cross-reactivity of shellfish allergens we developed an epitope conservation model using IgE binding epitopes available in the Immune Epitope Database and Analysis Resource (http://www.iedb.org/). We applied this method to a set of four different shrimp allergens, and successfully identified several non-cross-reactive as well as cross-reactive epitopes, which have been experimentally established to cross-react. Based on these findings we suggest that this method can be used for advanced component-resolved-diagnosis to identify patients sensitized to a specific shellfish group and distinguish from patients with extensive cross-reactivity to ingested and inhaled allergens from invertebrate sources.

Diagnosis of fish and shellfish allergies

Seafood allergy is a hypersensitive disorder with increasing prevalence worldwide. Effective and accurate diagnostic workup for seafood allergy is essential for clinicians and patients. Parvalbumin and tropomyosin are the most common fish and shellfish allergens, respectively. The diagnosis of seafood allergies is complicated by cross-reactivity among fish allergens and between shellfish allergens and other arthropods. Current clinical diagnosis of seafood allergy is a complex algorithm that includes clinical assessment, skin prick test, specific IgE measurement, and oral food challenges. Emerging diagnostic strategies, such as component-resolved diagnosis (CRD), which uses single allergenic components for assessment of epitope specific IgE, can provide critical information in predicting individualized sensitization patterns and risk of severe allergic reactions. Further understanding of the molecular identities and characteristics of seafood allergens can advance the development of CRD and lead to more precise diagnosis and improved clinical management of seafood allergies.

Cockroach is a major cross-reactive allergen source in shrimp-sensitized rural children in southern China

BACKGROUND

Little is known about the prevalence of food allergy (FA) in China. The aim of this study was to investigate the disparity of FA between urban and rural areas in southern China.

METHODS

EuroPrevall questionnaire responses were obtained from 5542 school-age children in urban Guangzhou and 5319 in rural Shaoguan. A case-control study enrolled 190 children with adverse reactions (ARs) after food intake as cases and 212 controls in Guangzhou, whereas 116 cases and 233 controls in Shaoguan. These subjects underwent skin prick test (SPT) and serum IgE measurements to food and inhalant allergens. Allergen extracts from shrimp, house dust mite (HDM), and cockroach were prepared for IgE cross-reactivity testing in 23 Guangzhou and 20 Shaoguan shrimp-sensitized subjects.

RESULTS

The prevalence of ARs to shrimp was higher in Guangzhou than in Shaoguan children (3.5% vs 1.4%, P < .001). However, sensitization rate to shrimp (SPT: 3.7% vs 11.2%, P = .015; IgE: 12.6% vs 36.2%, P < .001) and cockroach (SPT: 5.3% vs 33.5%; IgE: 2.6% vs 27.6%, P < .001) was lower in Guangzhou. A significant correlation between shrimp and HDM/cockroach IgE was found in Shaoguan children. The proportions of positive IgE to tropomyosin (Pen a 1, Der p 10) were lower than 7.4% in both areas. Cockroach allergen has a significantly higher inhibition rate of binding to IgE to house dust mite allergens in Shaoguan sera.

CONCLUSION

Shrimp is a common allergic food in southern China. Higher proportion of shrimp sensitization in rural subjects could be explained by cross-reactivity to cockroach. Tropomyosin was not a major allergen responding to the cross-reactivity.

How Different Parts of the World Provide New Insights Into Food Allergy

The prevalence and patterns of food allergy are highly variable in different parts of the world. Differences in food allergy epidemiology may be attributed to a complex interplay of genetic, epigenetic, and environmental factors, suggesting that mechanisms of food allergy may differ in various global populations. Genetic polymorphisms, migration, climate, and infant feeding practices all modulate food allergy risk, and possibly also the efficacy of interventions aimed at primary prevention of food allergy development. Approaches to diagnosis, treatment, and prevention of food allergy should thus be tailored carefully to each population's unique genetic and environmental make-up. Future research in the context of food allergy prevention should focus on elucidating factors determining differential responses between populations.

Mite-Induced Asthma and IgE Levels to Shrimp, Mite, Tropomyosin, Arginine Kinase, and Der p 10 Are the Most Relevant Risk Factors for Challenge-Proven Shrimp Allergy

BACKGROUND

Shrimp sensitization is common in the general population, but the presence of symptoms is only moderately related to sensitization. A point still at issue is which in vivo and/or in vitro tests (food challenge, component-resolved diagnosis, house dust mite [HDM] sensitization) can help in distinguishing shrimp-allergic subjects from subjects that are sensitized but tolerant.

METHODS

The aim of this study was to evaluate the role of IgE to the different shrimp and mite allergens in distinguishing shrimp challenge-positive from challenge-negative patients. Subjects with suspected hypersensitivity reactions to shrimp, positive skin prick tests (SPTs), and/or anti-shrimp IgE were submitted to open and double-blind placebo-controlled food challenges (DBPCFC). Specific IgE to shrimp, mites, and the recombinants rPen a 1, rDer p 1, 2, and 10 were tested using ImmunoCAP-FEIA. IgE immunoblotting was performed to identify the patients' allergenic profiles.

RESULTS

In total, 13 out of 51 (25.5%) patients with reported reactions to shrimp were truly shrimp allergic (7 DBPCFC positive and 6 with documented severe reactions). These patients had significantly higher skin test wheal diameters than nonallergic patients, as well as higher levels of IgE to rPen a 1 and rDer p 10. HDM-induced asthma and the simultaneous presence of anti-nDer p 1, 2, and 10 IgE levels increased the risk of true shrimp allergy.

CONCLUSION

Food challenge tests are mandatory for the diagnosis of shrimp allergy. Tropomyosin is associated with clinical reactivity. HDM-induced asthma and anti-mite IgE are risk factors for shrimp allergy.

Characterization of Sarcoptes scabiei Tropomyosin and Paramyosin: Immunoreactive Allergens in Scabies

Scabies is a human skin disease due to the burrowing ectoparasite Sarcoptes scabiei var. hominis resulting in intense itching and inflammation and manifesting as a skin allergy. Because of insufficient mite material and lack of in vitro propagation system for antigen preparation, scabies is a challenging disease to develop serological diagnostics. For allergen characterization, full-length S. scabiei tropomyosin (Sar s 10) was cloned, expressed in pET-15b, and assessed for reactivity with IgE antibodies from human sera. IgE binding was observed to Sar s 10 with sera collected from subjects with ordinary scabies, house dust mite (HDM)-positive and naive subjects and a diagnostic sensitivity of < 30% was observed. S. scabiei paramyosin (Sar s 11) was cloned, and expressed in pET-28a in three overlapping fragments designated Sspara1, Sspara2, and Sspara3. IgE and IgG binding was observed to Sspara2 and Sspara3 antigens with sera collected from ordinary scabies, and HDM-positive subjects, but no binding was observed with sera collected from naive subjects. Sspara2 displayed excellent diagnostic potential with 98% sensitivity and 90% specificity observed for IgE binding and 70% sensitivity for IgG. In contrast, the diagnostic sensitivity of Sspara3 was 84% for IgE binding and 40% for IgG binding. In combination, Sspara2 and Sspara3 provided an IgE sensitivity of 94%. This study shows that IgE binding to Sspara2 and Sspara3 is a highly sensitive method for diagnosis of scabies infestation in clinical practice. The developed enzyme-linked immunosorbent assay helps direct future development of a specific diagnostic tool for scabies.

Cross-reaction between Formosan termite (Coptotermes formosanus) proteins and cockroach allergens

Cockroach allergens can lead to serious allergy and asthma symptoms. Termites are evolutionarily related to cockroaches, cohabitate in human dwellings, and represent an increasing pest problem in the United States. The Formosan subterranean termite (Coptotermes formosanus) is one of the most common species in the southern United States. Several assays were used to determine if C. formosanus termite proteins cross-react with cockroach allergens. Expressed sequence tag and genomic sequencing results were searched for homology to cockroach allergens using BLAST 2.2.21 software. Whole termite extracts were analyzed by mass-spectrometry, immunoassay with IgG and scFv antibodies to cockroach allergens, and human IgE from serum samples of cockroach allergic patients. Expressed sequence tag and genomic sequencing results indicate greater than 60% similarity between predicted termite proteins and German and American cockroach allergens, including Bla g 2/Per a 2, Bla g 3/Per a 3, Bla g 5, Bla g 6/Per a 6, Bla g 7/Per a 7, Bla g 8, Per a 9, and Per a 10. Peptides from whole termite extract were matched to those of the tropomyosin (Bla g 7), arginine kinase (Per a 9), and myosin (Bla g 8) cockroach allergens by mass-spectrometry. Immunoblot and ELISA testing revealed cross-reaction between several proteins with IgG and IgE antibodies to cockroach allergens. Several termite proteins, including the hemocyanin and tropomyosin orthologs of Blag 3 and Bla g 7, were shown to crossreact with cockroach allergens. This work presents support for the hypothesis that termite proteins may act as allergens and the findings could be applied to future allergen characterization, epitope analysis, and clinical studies.

Allergic risks of consuming edible insects: A systematic review

The expected future demand for food and animal-derived protein will require environment-friendly novel food sources with high nutritional value. Insects may be one of such novel food sources. However, there needs to be an assessment of the risks associated with their consumption, including allergic risks. Therefore, we performed a systematic review aiming to analyse current data available regarding the allergic risks of consuming insects. We reviewed all reported cases of food allergy to insects, and studied the possibility of cross-reactivity and co-sensitisation between edible insects, crustaceans and house dust mites. We analysed a total of 25 articles - eight assessing the cross-reactivity/co-sensitisation between edible insects, crustaceans and house dust mites; three characterizing allergens in edible insects and 14 case reports, describing case series or prevalence studies of food allergy caused by insects. Cross-reactivity/co-sensitisation between edible insects and crustaceans seems to be clinically relevant, while it is still unknown if co-sensitisation between house dust mites and edible insects can lead to a food allergy. Additionally, more information is also needed about the molecular mechanisms underlying food allergy to insects, although current data suggest that an important role is played by arthropod pan-allergens such as tropomyosin or arginine kinase.

Shellfish allergens: tropomyosin and beyond

IgE-mediated shellfish allergy constitutes an important cause of food-related adverse reactions. Shellfish are classified into mollusks and crustaceans, the latter belonging to the class of arthropoda. Among crustaceans, shrimps are the most predominant cause of allergic reactions and thus more extensively studied. Several major and minor allergens have been identified and cloned. Among them, invertebrate tropomyosin, arginine kinase, myosin light chain, sarcoplasmic calcium-binding protein, and hemocyanin are the most relevant. This review summarizes our current knowledge about these allergens.

Changes of structure and IgE binding capacity of shrimp (Metapenaeus ensis) tropomyosin followed by acrolein treatment

The changes of structure and IgE binding capacity of shrimp tropomyosin following acrolein treatment are explored at the molecular level.

Allergen Valency, Dose, and FcεRI Occupancy Set Thresholds for Secretory Responses to Pen a 1 and Motivate Design of Hypoallergens

Ag-mediated crosslinking of IgE-FcεRI complexes activates mast cells and basophils, initiating the allergic response. Of 34 donors recruited having self-reported shrimp allergy, only 35% had significant levels of shrimp-specific IgE in serum and measurable basophil secretory responses to rPen a 1 (shrimp tropomyosin). We report that degranulation is linked to the number of FcεRI occupied with allergen-specific IgE, as well as the dose and valency of Pen a 1. Using clustered regularly interspaced palindromic repeat-based gene editing, human RBL^rαKO cells were created that exclusively express the human FcεRIα subunit. Pen a 1-specific IgE was affinity purified from shrimp-positive plasma. Cells primed with a range of Pen a 1-specific IgE and challenged with Pen a 1 showed a bell-shaped dose response for secretion, with optimal Pen a 1 doses of 0.1-10 ng/ml. Mathematical modeling provided estimates of receptor aggregation kinetics based on FcεRI occupancy with IgE and allergen dose. Maximal degranulation was elicited when ∼2700 IgE-FcεRI complexes were occupied with specific IgE and challenged with Pen a 1 (IgE epitope valency of ≥8), although measurable responses were achieved when only a few hundred FcεRI were occupied. Prolonged periods of pepsin-mediated Pen a 1 proteolysis, which simulates gastric digestion, were required to diminish secretory responses. Recombinant fragments (60-79 aa), which together span the entire length of tropomyosin, were weak secretagogues. These fragments have reduced dimerization capacity, compete with intact Pen a 1 for binding to IgE-FcεRI complexes, and represent a starting point for the design of promising hypoallergens for immunotherapy.

Allergens and molecular diagnostics of shellfish allergy: Part 22 of the Series Molecular Allergology

Shellfish belongs to "The Big 8" food groups causing allergy, which often does not outgrow during childhood. Shellfish is one of the main food allergens in adults and constitutes a diverse group of species subdivided into crustaceans and mollusks, which seem to include similar but also different allergens. Several pan-allergens are characterized in detail, including tropomyosin and arginine kinase, responsible for clinical cross-reactivity with other invertebrate allergen sources, embracing mites, insects, and parasites. Currently, at least seven different shellfish allergens have been identified, mostly from crustaceans. However, only three recombinant allergens are available for IgE-based routine diagnostic, including tropomyosin, arginine kinase, and sarcoplasmic Ca²⁺-binding protein. Other allergens include myosin light chain, troponin C, triosephosphate isomerase, and actin. This review summarizes the current advances on the molecular characterization of shellfish allergens, clinical cross-reactivity, and current diagnostic approaches for the management of this life-threatening disease.

How relevant is panallergen sensitization in the development of allergies?

Panallergens comprise various protein families of plant as well as animal origin and are responsible for wide IgE cross-reactivity between related and unrelated allergenic sources. Such cross-reactivities include reactions between various pollen sources, pollen and plant-derived foods as well as invertebrate-derived inhalants and foodstuff. Here, we provide an overview on the most clinically relevant panallergens from plants (profilins, polcalcins, non-specific lipid transfer proteins, pathogenesis-related protein family 10 members) and on the prominent animal-derived panallergen family, tropomyosins. In addition, we explore the role of panallergens in the sensitization process and progress of the allergic disease. Emphasis is given on epidemiological aspects of panallergen sensitization and clinical manifestations. Finally, the issues related to diagnosis and therapy of patients sensitized to panallergens are outlined, and the use of panallergens as predictors for cross-reactive allergy and as biomarkers for disease severity is discussed.

Human Helminths and Allergic Disease: The Hygiene Hypothesis and Beyond

There is much debate about the interaction between helminths and allergic disease. The "Hygiene Hypothesis," a very popular concept among scientists and the lay public, states that infections, especially during childhood, can protect against allergic diseases. Indeed, helminth infections are known to induce regulatory responses in the host that can help the control of inflammation (including allergic inflammation). However, these infections also induce type-2-associated immune responses including helminth-specific IgE that can cross-react against environmental allergens and mediate IgE-driven effector responses. Thus, it is the delicate balance between the parasites' anti- and pro-allergenic effects that define the helminth/allergy interface.

Seafood-Associated Shellfish Allergy: A Comprehensive Review

Shellfish are diverse, serve as main constituents of seafood, and are extensively consumed globally because of their nutritional values. Consequently, increase in reports of IgE-mediated seafood allergy is particularly food associated to shellfish. Seafood-associated shellfish consists of crustaceans (decapods, stomatopods, barnacles, and euphausiids) and molluskans (gastropods, bivalves, and cephalopods) and its products can start from mild local symptoms and lead to severe systemic anaphylactic reactions through ingestion, inhalation, or contact like most other food allergens. Globally, the most commonly causative shellfish are shrimps, crabs, lobsters, clams, oysters, and mussels. The prevalence of shellfish allergy is estimated to be 0.5-2.5% of the general population but higher in coastal Asian countries where shellfish constitute a large proportion of the diet. Diversity in allergens such as tropomyosin, arginine kinase, myosin light chain, and sarcoplasmic binding protein are from crustaceans whereas tropomyosin, paramyosin, troponin, actine, amylase, and hemoyanin are reported from molluskans shellfish. Tropomyosin is the major allergen and is responsible for cross-reactivity between shellfish and other invertebrates, within crustaceans, within molluskans, between crustaceans vs. molluskans as well as between shellfish and fish. Allergenicity diagnosis requires clinical history, in vivo skin prick testing, in vitro quantification of IgE, immunoCAP, and confirmation by oral challenge testing unless the reactions borne by it are life-threatening. This comprehensive review provides the update and new findings in the area of shellfish allergy including demographic, diversity of allergens, allergenicity, their cross-reactivity, and innovative molecular genetics approaches in diagnosing and managing this life-threatening as well as life-long disease.

Changes in Food-Specific IgE Over Time in the National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

Food allergy prevalence appears to have recently risen, with larger increases among non-Hispanic blacks. However, it is unclear whether these trends represent shifts in recognition of food allergy or in sensitization.

OBJECTIVE

The objective of this study was to determine whether sensitization to common food allergens increased in US children from 1988-1994 to 2005-2006 and whether these trends differed by race and/or ethnicity.

METHODS

Food-specific immunoglobulin E (IgE; to peanut, milk, egg, and shrimp) was measured by ImmunoCAP in stored sera from subjects aged 6-19 in the National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and was compared with NHANES 2005-2006. Sensitization to foods was defined as overall (IgE ≥ 0.35 kU/L), moderate level (IgE ≥ 2 kU/L), and high level (IgE ≥ commonly used 95% predictive values). Sensitization to individual and combined foods was compared between surveys, with analyses further stratified by race and/or ethnicity.

RESULTS

A total of 7896 subjects (NHANES III: n = 4995, NHANES 2005-2006: n = 2901) were included. In NHANES III, the prevalence of food sensitization was 24.3% (95% confidence interval [CI]: 22.1-26.5) compared with 21.6% (95% CI: 19.5-23.7) in NHANES 2005-2006. There were no significant changes in the prevalence of any level of milk, egg, or peanut sensitization, but shrimp sensitization at all levels decreased markedly; overall sensitization NHANES III: 11.2% (95% CI: 10.0-12.5) versus NHANES 2005-2006: 6.1% (95% CI: 4.5-7.7). There was a trend toward the increased prevalence of moderate- and high-level sensitization to the combination of milk, egg, and peanut among non-Hispanic blacks but not other groups.

CONCLUSIONS

In contrast to our expectations, sensitization to common food allergens did not increase between the late 1980s/early 1990s and the mid-2000s among US 6-19 year olds, and in fact decreased to shrimp.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

Immunoglobulin E to allergen components of house dust mite in Korean children with allergic disease

BACKGROUND

House dust mites (HDMs) are important sources of indoor allergens. Seventeen components have been identified from Dermatophagoides pteronyssinus (Der p).

OBJECTIVE

Our aim was to define the prevalence of specific IgE to components of Der p in Korea and investigate the clinical features of them in children with allergic disease.

METHODS

We performed a prospective evaluation of 80 HDM sensitized patients with history of allergic rhinitis (AR), atopic dermatitis (AD), asthma and urticaria (UC). Patients underwent ImmunoCAP for total IgE, Der p, Der f, Der p 1, Der p 2, and Der p 10.

RESULTS

Seventy-nine patients had detectable serum IgE to Der p, 80 patients were sensitized to Der f, 66 patients were sensitized to Der p 1, 63 patients to Der p 2, and 7 patients were sensitized to Der p 10. Der p 1 specific IgE was significantly lower in the UC group compared with the AD and AR group. Total IgE was significantly higher in the Der p 10 sensitized group. Der p 10 serum IgE level was highly correlated with crab and shrimp specific IgE. There was a significant positive correlation between total IgE and specific IgE to Der p and its components and Der f.

CONCLUSION

Sensitization to HDM and its components in Korea is similar to previous studies from temperate climate. The determination of Der p 1, Der p 2, and Der p 10 specific IgE helps in obtaining additional information in regards to allergic disease.

Shellfish and House Dust Mite Allergies: Is the Link Tropomyosin?

Crustacean shellfish allergy is an important cause of food allergy and anaphylaxis in Asia. The major allergen in shellfish allergy is tropomyosin, a pan-allergen that is also found in house dust mites and cockroaches. Tropomyosins from house dust mites (HDMs) have a high sequence homology to shellfish tropomyosins, and cross-reactivity between HDM and shrimp tropomyosins has been demonstrated. Exposure to inhaled tropomyosins from house dust mites has been postulated to be the primary sensitizer for shellfish allergy, in a reaction analogous to the oral allergy (inhalant-food) syndrome. This notion is supported by indirect data from the effects of HDM immunotherapy on shellfish allergy, and strong correlations of shellfish and HDM sensitization. HDM immunotherapy has been reported to induce both shrimp allergy in non-allergic patients and shrimp tolerance in shrimp-allergic patients. Epidemiological surveys have also demonstrated a strong correlation between shellfish and HDM sensitization in both hospital-based and community-based studies. Unexposed populations have also been shown to develop sensitization-shellfish sensitization in orthodox Jews with no history of shellfish consumption was associated with HDM sensitization. Reciprocally, HDM sensitization in an Icelandic population living in a HDM-free environment was associated with shrimp sensitization. In vitro IgE inhibition studies on sera in shrimp-allergic Spanish patients indicate that mites are the primary sensitizer in shrimp-allergic patients living in humid and warm climates. Current data supports the hypothesis that tropomyosin is the link between HDM and shellfish allergies. The role of tropomyosin in HDM and shellfish allergies is a fertile field for investigation as it may provide novel immunotherapeutic strategies for shellfish allergy.

Efficacy of Sublingual Immunotherapy with Dermatophagoides farinae Extract in Monosensitized and Polysensitized Patients with Allergic Rhinitis: Clinical Observation and Analysis

AIM

To investigate differences in the efficacy of sublingual immunotherapy with Dermatophagoides farinae drops in monosensitized and polysensitized allergic rhinitis patients.

METHODS

The patients enrolled in the study were treated for more than one year by sublingual immunotherapy (SLIT) using Dermatophagoides farinae drops and were divided into a monosensitized group (n = 20) and a polysensitized group (n = 30). Total nasal symptom scores of patients before and after SLIT were analyzed to evaluate the curative effect. The phylogenetic tree of dust mite allergens as well as other allergens that were tested by skin prick test was constructed to help the analysis.

RESULTS

There was no significant difference in the efficacy of SLIT between dust mite monosensitized and polysensitized patients.

CONCLUSIONS

Both dust mite monosensitized and polysensitized patients could be cured by SLIT using Dermatophagoides farinae drops. This study provides a reference for the selection of allergens to be used in immunotherapy for polysensitized AR patients.

Molecular Diagnosis of Shrimp Allergy: Efficiency of Several Allergens to Predict Clinical Reactivity

BACKGROUND

The diagnosis of shellfish allergy remains a challenge for clinicians. Several shellfish allergens have been characterized and their IgE epitopes identified. However, the clinical relevance of this sensitization is still not clear.

OBJECTIVE

The objective of this study was to identify allergens and epitopes associated with clinical reactivity to shrimp.

METHODS

Shrimp-sensitized subjects were recruited and grouped based on the history of shrimp-allergic reactions and challenge outcome. IgE reactivity to recombinant crustacean allergens, and IgE and IgG4 reactivity to peptides were determined. Subjects sensitized to dust mites and/or cockroach without shrimp sensitization or reported allergic reactions, as well as nonatopic individuals, were used as controls.

RESULTS

A total of 86 subjects were recruited with a skin prick test to shrimp; 74 reported shrimp-allergic reactions, 58 were allergic (38 positive double-blind placebo-controlled food challenge and 20 recent anaphylaxis), and 16 were tolerant. All subjects without a history of reactions had negative challenges. The individuals with a positive challenge more frequently recognized tropomyosin and sarcoplasmic calcium-binding proteins than those found tolerant by the challenge. Especially a sarcoplasmic-calcium-binding-protein positive test is very likely to result in a positive challenge, though the frequency of recognition is low. Subjects with dust mite and/or cockroach allergy not sensitized to shrimp recognized arginine kinase and hemocyanin. Several epitopes of these allergens may be important in predicting clinical reactivity.

CONCLUSION

Tropomyosin and sarcoplasmic-calcium-binding-protein sensitization is associated with clinical reactivity to shrimp. Myosin light chain testing may help in the diagnosis of clinical reactivity. Arginine kinase and hemocyanin appear to be cross-reacting allergens between shrimp and arthropods. Detection of IgE to these allergens and some of their epitopes may be better diagnostic tools in the routine workup of shrimp allergy.

Evaluation of the applicability of the Immuno-solid-phase allergen chip (ISAC) assay in atopic patients in Singapore

Background/Objective

Molecular-based allergy diagnostics are gaining popularity in clinical practice. Our aim was to evaluate their role in the tropics, given the inherent genetic and environmental differences.

Methods

We recruited subjects with history of atopy and collected data on demographics and atopic symptoms using validated questionnaires. Subjects underwent a series of skin prick tests (SPT). Serum total and specific IgE levels were measured using ImmunoCAP FEIA and ImmunoCAP ISAC®, respectively. We describe their pattern of sensitization and agreement between test methods.

Results

A total of 135 subjects were recruited; mean ± SD age of 31.18 ± 12.72 years, 52.7% female. Allergic rhinitis (AR) was the most prevalent clinical manifestation of atopy (70.7%), followed by atopic dermatitis (AD) (50.5%) and asthma (26.2%). Polysensitization was seen in 51.1% of subjects by both SPT and ISAC. House dust mites (HDM) were the dominant allergen, with sensitization in 67.8% and 62% of subjects on SPT and ISAC, respectively. A group of subjects with monosensitization to B. tropicalis was identified. HDM sensitization was strongly associated with AR, while AD and asthma were not associated with sensitization to any allergen. Agreement between SPT and ISAC was mostly suboptimal. Greatest agreement was documented for the measurement of HDM sensitization with both methods (κ = 0.64). Sensitization to the bulk of the remaining allergens in the ISAC panel was infrequent.

Conclusion

Multiplex methods should not be used as a screening tool, especially in a population with lower rates of polysensitization and a dominant sensitizing allergen. There may be a role in adjusting the antigen spectrum in the ISAC panel to regional differences.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-015-0053-z) contains supplementary material, which is available to authorized users.

Food allergy: a practice parameter update-2014

This parameter was developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology (AAAAI); the American College of Allergy, Asthma & Immunology (ACAAI); and the Joint Council of Allergy, Asthma & Immunology (JCAAI). The AAAAI and the ACAAI have jointly accepted responsibility for establishing "Food Allergy: A practice parameter update-2014." This is a complete and comprehensive document at the current time. The medical environment is a changing one, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, ACAAI, and JCAAI. These parameters are not designed for use by pharmaceutical companies in drug promotion.

New insights into the allergenicity of tropomyosin: a bioinformatics approach

The invertebrate panallergen tropomyosin is a protein with an extremely simple folding. This makes it a perfect target for investigating structural differences between invertebrate and vertebrate tropomyosins, which are not considered allergenic. Phylogenetic and sequence analyses were conducted in order to explore the differences in primary structure between several tropomyosins and to promote an experimental development in the field of food allergy, based on the study of tropomyosin. The phylogenetic analyses showed that tropomyosin is a useful evolutionary marker. The phylogenetic trees obtained with tropomyosin were not always phylogenetically correct, but they might be useful for allergen avoidance by tropomyosin allergic individuals. Sequence analyses revealed that the probability of alpha helix folding in invertebrate tropomyosins was lower than in all the studied vertebrate ones, except for the Atlantic bluefin tuna Thunnus thynnus tropomyosin. This suggested that the lack of alpha helix folding may be involved in the immunogenicity of tropomyosins. More specifically, the regions adjacent to the positions 133-135 and 201 of the invertebrate tropomyosins, presented lower probability of alpha helix folding than those of vertebrates and are candidates to be responsible for their allergenicity.

New shrimp IgE-binding proteins involved in mite-seafood cross-reactivity

SCOPE

Shrimp is a seafood consumed worldwide and the main cause of severe allergenic reactions to crustaceans. Seafood allergy has been related to mite sensitization, mainly mediated by tropomyosin, but other proteins could be involved. The aim of the study was to identify new shrimp allergens implicated in mite-seafood cross-reactivity (CR) in two different climate populations: dry and humid climates.

METHODS AND RESULTS

Shrimp and mite IgE-binding profiles of patients from continental dry and humid climates were analyzed by immunoblotting, and the most frequently recognized Solenocera melantho shrimp proteins were identified by MS as α-actinin, β-actin, fructose biphosphate aldolase, arginine kinase, sarcoplasmic calcium-binding protein, and ubiquitin. Using inhibition immunoblot assays, we demonstrate that tropomyosin and ubiquitin were responsible for mite-seafood CR from both climates; but also α-actinin and arginine kinase are implicated in dry- and humid-climate populations, respectively. Reciprocal inhibition assays demonstrated that mites are the primary sensitizer in humid-climate, as shrimp is in continental dry-climate population.

CONCLUSION

Several new shrimp allergens have been identified and should be considered in the diagnosis and treatment of shrimp allergy and mite-seafood CR. Differences in mite-seafood CR were founded to be based on the climate.

House dust mite (Der p 10) and crustacean allergic patients may react to food containing Yellow mealworm proteins

SCOPE

Due to the imminent growth of the world population, shortage of protein sources for human consumption will arise in the near future. Alternative and sustainable protein sources (e.g. insects) are being explored for the production of food and feed. In this project, the safety of Yellow mealworms (Tenebrio molitor L.) for human consumption was tested using approaches as advised by the European Food Safety Authority for allergenicity risk assessment.

METHODS AND RESULTS

Different Yellow mealworm protein fractions were prepared, characterised, and tested for cross-reactivity using sera from patients with an inhalation or food allergy to biologically related species (House dust mite (HDM) and crustaceans) by immunoblotting and basophil activation. Furthermore, the stability was investigated using an in vitro pepsin digestion test. IgE from HDM- and crustacean allergic patients cross-reacted with Yellow mealworm proteins. This cross-reactivity was functional, as shown by the induction of basophil activation. The major cross-reactive proteins were identified as tropomyosin and arginine kinase, which are well known allergens in arthropods. These proteins were moderately stable in the pepsin stability test.

CONCLUSION

Based on these cross-reactivity studies, there is a realistic possibility that HDM- and crustacean allergic patients may react to food containing Yellow mealworm proteins.

Mammalian-derived respiratory allergens - implications for diagnosis and therapy of individuals allergic to furry animals

Furry animals cause respiratory allergies in a significant proportion of the population. A majority of all mammalian allergens are spread as airborne particles, and several have been detected in environments where furry animals are not normally kept. The repertoire of allergens from each source belongs to a restricted number of allergen families. Classification of allergen families is particularly important for the characterization of allergenicity and cross-reactivity of allergens. In fact, major mammalian allergens are taken from only three protein families, i.e. the secretoglobin, lipocalin and kallikrein families. In particular, the lipocalin superfamily harbours major allergens in all important mammalian allergen sources, and cross-reactivity between lipocalin allergens may explain cross-species sensitization between mammals. The identification of single allergen components is of importance to improve diagnosis and therapy of allergic patients using component-resolved diagnostics and allergen-specific immunotherapy (ASIT) respectively. Major disadvantages with crude allergen extracts for these applications emphasize the benefits of careful characterization of individual allergens. Furthermore, detailed knowledge of the characteristics of an allergen is crucial to formulate attenuated allergy vaccines, e.g. hypoallergens. The diverse repertoires of individual allergens from different mammalian species influence the diagnostic potential and clinical efficacy of ASIT to furry animals. As such, detailed knowledge of individual allergens is essential for adequate clinical evaluation. This review compiles current knowledge of the allergen families of mammalian species, and discusses how this information may be used for improved diagnosis and therapy of individuals allergic to mammals.

Mast cell-based electrochemical biosensor for quantification of the major shrimp allergen Pen a 1 (tropomyosin)

A novel cell-based electrochemical biosensor was developed to quantify major shrimp allergen Pen a 1 (tropomyosin) and to assess its immunoglobulin E (IgE)-mediated hypersensitivity. Rat basophilic leukemia (RBL-2H3) mast cells, encapsulated in type I collagen, were immobilized on a self-assembled l-cysteine/gold nanoparticle (AuNPsCys)-modified gold electrode to monitor IgE-mediated mast cell sensitization and activation. The exposure of dinitrophenol-bovine serum albumin (DNP-BSA), as a model antigen that stimulates mast cells, induced a robust and long-lasting electrochemical impedance signal in a dose-dependent manner which efficiently measured degranulation of anti-DNP IgE-stimulated mast cells. Then this mast cell-based biosensor was applied into quantification for the shrimp allergen with anti-shrimp tropomyosin IgE-sensitization. The electrochemical impedance spectroscopy (EIS) results showed that the impedance value (Ret) increased with the concentration of purified shrimp allergen Pen a 1 (tropomyosin) in range of 0.5-0.25 μg mL(-1) with the detection limit as 0.15 μg mL(-1), and the electrochemical result was confirmed by β-hexosaminidase assay and scanning electron microscopic morphological (SEM) analysis. Thus, a simple, label-free, and sensitive method for the determination of shrimp allergens was proposed and demonstrated here, implying a highly versatile biosensor for food allergen detection and prediction.