Not all shellfish “allergy” is allergy! Clin Transl Allergy. 2011;1:3. [PMID: 22410209 PMCID: PMC3294628 DOI: 10.1186/2045-7022-1-3]

Real-World Sensitization and Tolerance Pattern to Seafood in Fish-Allergic Individuals

BACKGROUND

Seafood is a common cause of food allergy and anaphylaxis, but there are limited published real-world data describing the clinical presentation of fish and shellfish allergies.

OBJECTIVE

This study aimed to examine the clinical characteristics, immunological profile, and tolerance pattern to fish, crustaceans, and mollusks in fish-allergic individuals.

METHODS

Patients presenting with IgE-mediated fish allergy between 2016 and 2021 were recruited. A comprehensive sensitization profile including specific IgE and skin prick test to various fish and shellfish species and a detailed clinical history including individuals' recent seafood consumption were evaluated.

RESULTS

A total of 249 fish-allergic individuals (aged 4.2 ± 5.8 years) were recruited from 6 allergy clinics in Hong Kong, and they had experienced their fish-allergic reaction 2.2 ± 3.4 years before enrollment. Seventy-five subjects (30%) reacted to either grass carp, salmon, grouper, or cod in oral food challenges. We identified an IgE sensitization gradient that corresponded to the level of β-parvalbumin in fish. In total, 40% of fish-allergic individuals reported tolerance to 1 or more types of fish, more commonly to fish with a lower β-parvalbumin level such as tuna and salmon, compared with β-parvalbumin-rich fish such as catfish and grass carp. Despite fish and shellfish cosensitization, 41% of individuals reported tolerance to crustaceans, mollusks, or both, whereas shellfish avoidance occurred in half of the fish-allergic individuals, of whom 33% lacked shellfish sensitization.

CONCLUSIONS

Fish allergy commonly presents in early childhood. A considerable proportion of fish-allergic patients are selectively tolerant to certain fish, typically those with lower levels of β-parvalbumin. There is an unmet need to promote precision medicine for seafood allergies.

Allergen Diversity and Abundance in Different Tissues of the Redclaw Crayfish (Cherax quadricarinatus)

Shellfish allergy affects ~2.5% of the global population and is a type I immune response resulting from exposure to crustacean and/or molluscan proteins. The Australian Redclaw crayfish (Cherax quadricarinatus) is a freshwater species endemic to and farmed in northern Australia and is becoming an aquaculture species of interest globally. Despite being consumed as food, allergenic proteins from redclaw have not been identified or characterised. In addition, as different body parts are often consumed, it is conceivable that redclaw tissues vary in allergenicity depending on tissue type and function. To better understand food-derived allergenicity, this study characterised allergenic proteins in various redclaw body tissues (the tail, claw, and cephalothorax) and how the stability of allergenic proteins was affected through cooking (raw vs. cooked tissues). The potential of redclaw allergens to cross-react and cause IgE-binding in patients allergic to other shellfish (i.e., shrimp) was also investigated. Raw and cooked extracts were prepared from each body part. SDS-PAGE followed by immunoblotting was performed to determine allergen-specific antibody reactivity to sarcoplasmic calcium-binding protein and hemocyanin, as well as to identify redclaw proteins binding to IgE antibodies from individual and pooled sera of shrimp-allergic patients. Liquid chromatography-mass spectrometry (LC/MS) was utilised to identify proteins and to determine the proportion within extracts. Known crustacean allergens were found in all tissues, with a variation in tissue distribution (e.g., higher levels of hemocyanin in the claw and cephalothorax than in the tail). The proportion of some allergens as a percentage of remaining heat-stable proteins increased in cooked tissues. Previously described heat-stable allergens (i.e., hemocyanin and sarcoplasmic calcium-binding protein) were found to be partially heat-labile. Immunoblotting indicated that shrimp-allergic patients cross-react to redclaw allergens. IgE-binding bands, analysed by LC/MS, identified up to 11 known shellfish allergens. The findings of this study provide fundamental knowledge into the diagnostic and therapeutic field of shellfish allergy.

Anaphylaxis after Shrimp Intake in a European Pediatric Population: Role of Molecular Diagnostics and Implications for Novel Foods

(1) Background: Tropomyosin is a major cause of shellfish allergy and anaphylaxis triggered by food. It acts as a pan-allergen, inducing cross-reactivity in insects, dust mites, crustaceans, and mollusks. Our study investigates anaphylaxis in children with asthma or atopic diseases after consuming tropomyosin-containing food. (2) Methods: We analyzed the molecular sensitization profiles of pediatric patients at the University of Campania 'Luigi Vanvitelli' from 2017 to 2021, with conditions such as allergic rhinitis, asthma, atopic dermatitis, urticaria, and food allergies. (3) Results: Out of a total of 253 patients aged 1 to 18 years (167 males, 86 females), 21 patients (8.3%) experienced anaphylaxis after shrimp ingestion. All 21 (100%) were sensitized to various tropomyosins: Pen m 1 (100%), Der p 10 (90.5%), Ani s 3 (81%), and Bla g 7 (76.2%). Clinical symptoms included allergic asthma (76.2%), atopic dermatitis (61.9%), urticaria (38.1%), and allergic rhinitis (38.1%). (4) Conclusions: Crustaceans and mollusks are major allergens in Italy and Europe, requiring mandatory declaration on food labels. Italian pediatric patients demonstrated significant anaphylaxis after consuming shrimp, often accompanied by multiple atopic disorders such as asthma, rhinitis, and atopic dermatitis. Considering the cross-reactivity of tropomyosin among various invertebrates and the emergence of 'novel foods' containing insect flours in Europe, there is ongoing debate about introducing precautionary labeling for these products.

Evaluation of Der p 10 in a Cohort of European Children: Role of Molecular Diagnostics and Clinical Features

Background

Allergy toward the dust mite is steadily increasing on the European continent. This sensitization may be a risk factor for developing sensitization to other mite molecules such as tropomyosin Der p 10. This molecule often correlates with food allergy and the risk of anaphylaxis after ingesting mollusks and shrimps.

Materials and Methods

We analyzed the sensitization profiles by ImmunoCAP ISAC of pediatric patients from 2017 to 2021. The patients under investigation were being followed for atopic disorders such as allergic asthma and food allergies. The study aimed to analyze the prevalence of sensitization toward Der p 10 in our pediatric population and assess the related clinical symptoms and reactions after ingestion of foods containing tropomyosins.

Results

This study included 253 patients; 53% were sensitized toward Der p 1 and Der p 2; 10.4% were also sensitized to Der p 10. Assessing patients sensitized to Der p 1 or Der p 2, and Der p 10, we observed that 78.6% were affected by asthma (p < 0.005) and had a history of prior anaphylaxis after ingestion of shrimp or shellfish (p < 0.0001).

Conclusion

The component-resolved diagnosis gave us a deeper understanding of patients' molecular sensitization profiles. Our study showed that a fair proportion of children sensitive to Der p 1 or Der p 2 are also sensitive to Der p 10. However, many patients sensitized to all three molecules had a high risk of asthma and anaphylaxis. Therefore, the assessment of Der p 10 sensitization should be considered in atopic patients with sensitization to Der p 1 and Der p 2 to avoid encountering possible adverse reactions after ingesting foods containing tropomyosins.

Contamination status of paralytic shellfish toxins in shellfish from Southeastern China in 2017-2021

Harmful algal blooms is a widespread problem in aquatic ecosystems, in particular dinoflagellates that produce PSTs which are harmful to animal and human health. To explore the contamination status of PSTs in shellfish in the Southeastern China, a total of 2355 shellfish samples were analyzed by ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to study the toxin profiles of the 10 PSTs collected from the southeast coast of China from 2017 to 2021. From 2355 shellfish samples, 257 were detected (10.91%), with the highest value in samples of Perna viridis. Among the six source areas in China, the samples from Fujian recorded the highest detected rate (15.28%). PSTs were found in Fuzhou, Ningde, Quanzhou, Putian, Zhangzhou, and Xiamen, with Quanzhou and Fuzhou having the highest and lowest detection rates of 15.28% and 4.23%, respectively. Saxitoxin (STX), neosaxitoxin (neoSTX), gonyautoxin (GTX1, GTX2, GTX3, GTX4), N-sulfocarbamoyl toxin (GTX5), and decarbamoyl toxin (dcSTX, dcGTX2, dcGTX3) were detected, and GTX5 and dcGTX2 were dominant. In addition, the samples containing PSTs were mostly concentrated in May to August. The study confirms the risks of PSTs to shellfish consumers in the region. It will offer a great foundation for future monitoring of marine toxins and protecting the health of seafood consumers in China. This is the first detailed evaluation of PSTs occurrences and their profiles in shellfish from the Southeastern China over a period of multiple years. HIGHLIGHTS: 2355 mussels from China were analyzed by UPLC-MS/MS for PSTs in 2017-2021. The predominant PSTs were GTX5, neoSTX and dcGTX2. Arca granosa and Crassostyea gigas exhibited higher levels than other shellfish. Shellfish containing PSTs were mostly concentrated in May to August. Maximum detected level in shellfish was 2137.10 ug STXeq/kg.

A new real-time PCR assay to specifically detect crustaceans in vegan raw materials and vegan shrimps

Contamination of vegan products and vegan shrimps with real shrimps and crustaceans must be avoided to comply with vegan claims, even more for preventing strong allergenic reactions. Therefore, the detection of crustaceans must be reliable and sensitive enough for authenticity, traceability, and food safety purposes. A new real-time PCR assay was developed targeting the mitochondrial 16S rRNA gene of crustaceans and was optimised to avoid critical mismatches with primers and probe. By testing several crustacean species and common food ingredients, the method was demonstrated to be specific to crustaceans only. To comply with the limit of non-vegan contamination established at 0.1% (w/w) by the European Vegetarian Union, dedicated cut-off C_T values were determined on vegan raw materials and on vegan shrimps spiked with crustacean materials. The method reached a sensitivity ≤ 0.0005% (w/w), which was further confirmed on reference materials containing a similar amount of crustacean.

Aquatic food animals in the United States: Status quo and challenges

This review summarizes (1) the U.S. status quo for aquatic food animal production and marketing; (2) major food safety and quality issues/concerns for aquatic food animals in the United States, including fish misbranding, finfish/shellfish allergies, pathogens, toxins and harmful residues, microplastics, and genetically engineered salmon; and (3) various U.S. regulations, guidances, and detection methods for the surveillance of fishery products. Overall, fish misbranding is the biggest challenge in the United States due to the relatively low inspection rate. In addition, due to the regulatory differences among countries, illegal animal drugs and/or pesticide residues might also be identified in imported aquatic food animals. Future regulatory and research directions could focus on further strengthening international cooperation, enhancing aquatic food animal inspection, and developing reliable, sensitive, and highly efficient detection methods.

Occupational Allergic Sensitization Among Workers Processing King Crab (Paralithodes camtschaticus) and Edible Crab (Cancer pagurus) in Norway and Identification of Novel Putative Allergenic Proteins

Introduction: Asthma and allergy occur frequently among seafood processing workers, with the highest prevalence seen in the crustacean processing industry. In this study we established for the first time the prevalence of allergic sensitization in the Norwegian king- and edible crab processing industry and characterized the IgE-reactive proteins.

Materials and Methods: Two populations of crab processing workers participated; 119 king crab and 65 edible crab workers. The investigation included information on work tasks and health through a detailed questionnaire. Allergic sensitization was investigated by crab-specific IgE quantification and skin prick tests (SPT) to four in-house prepared crab extracts; raw meat, cooked meat, raw intestines and raw shell. Allergen-specific IgE binding patterns were analyzed by IgE immunoblotting to the four allergen extracts using worker serum samples. Total proteins in crab SPT extracts and immunoblot-based IgE binding proteins were identified by mass spectrometric analysis.

Results: Positive SPTs were established in 17.5% of king- and 18.1% of edible crab workers, while elevated IgE to crab were demonstrated in 8.9% of king- and 12.2% of edible crab processing workers. There was no significant difference between the king and edible crab workers with respect to self-reported respiratory symptoms, elevated specific IgE to crab or SPT results. Individual workers exhibited differential IgE binding patterns to different crab extracts, with most frequent binding to tropomyosin and arginine kinase and two novel IgE binding proteins, hemocyanin and enolase, identified as king- and edible crab allergens.

Conclusions: Occupational exposure to king- and edible crabs may frequently cause IgE mediated allergic sensitization. Future investigations addressing the diagnostic value of crab allergens including tropomyosin and arginine kinase and the less well-known IgE-binding proteins hemocyanin and enolase in a component-resolved diagnostic approach to crab allergy should be encouraged.

Identification of potential allergens in larva, pupa, moth, silk, slough and feces of domestic silkworm (Bombyx mori)

The silkworm (Bombyx mori) is an important economic insect that can be used as food in many countries in Asia. However, silkworms and their metabolites are an important source of allergens, which can induce severe allergic reactions. So far, there are no systematic studies on the potential allergens in silkworm and its metabolites. These studies have important guiding significance for the prevention, diagnosis, and treatment of silkworm allergy. The aim of this study was to identify the potential allergens from larva, pupa, moth, silk, slough and feces of silkworm and analyze the sequence homology of silkworm allergens with other allergens identified in the Allergenonline database. We have found 45 potential allergens in silkworm. The results of the homology comparison suggested that silkworm allergens likely cross-react with those of Dermatophagoides farinae, Aedes aegypti, Tyrophagus putrescentiae, Triticum aestivum and Malassezia furfur.

Clinical Management of Seafood Allergy

Seafood plays an important role in human nutrition and health. A good patient workup and sensitive diagnostic analysis of IgE antibody reactivity can distinguish between a true seafood allergy and other adverse reactions generated by toxins or parasites contaminating ingested seafood. The 2 most important seafood groupings include the fish and shellfish. Shellfish, in the context of seafood consumption, constitutes a diverse group of species subdivided into crustaceans and mollusks. The prevalence of shellfish allergy seems to be higher than that of fish allergy, with an estimate of up to 3% in the adult population and fin fish allergy prevalence of approximately 1%. Clinical evaluation of the seafood-allergic patient involves obtaining a detailed history and obtaining in vivo and/or in vitro testing with careful interpretation of results with consideration of cross-reactivity features of the major allergens. Oral food challenge is useful not only for the diagnosis but also for avoiding unnecessary dietary restrictions. In this review, we highlight some of the recent reports to provide solid clinical and laboratory tools for the differentiation of fish allergy from shellfish allergy, enabling best treatment and management of these patients.

Food Allergy: Catering for the Needs of the Clinician

The practice of food allergy (FA) for clinicians has boomed, with a dramatic rise in the number of patients and families seeking care and with many advances on several fronts. The practice itself sometimes is evidence-based science and sometimes an art of pattern and phenotype recognition. This article examines the tools for diagnosis and management and therapy options available to physicians providing care for patients with FA. The article touches on pressing needs of clinicians and highlights the rapid and important movements in national and international support and advances that will have a positive impact on the field of FA.

Shrimp sensitization in house dust mite allergic patients

Shrimp tropomyosin has a similar structure to house dust mite (HDM) tropomyosin. In this research, 232 adult patients with symptoms of persistent allergic rhinitis were randomly selected. In the group, 59% were sensitized to Dermatophagoides pteronyssinus and 57.8% to Dermatophagoides farinae. In total, 128 (55.2%) patients were sensitized to both HDM species and 143 (61.6%) to at least one. Slightly over a quarter (25.4%) of patients were sensitized to shrimp. Of the 35 shrimp-sensitized patients, the sensitization to Der p 10 and Pen a 1 was found in 11 cases (31.4%). There was a strong correlation between IgE Pen a 1 and IgE Der p 10 concentrations. The results indicate that there are other allergens responsible for a high incidence of shrimp sensitization in HDM-sensitized patients. A high convergence of Der p 10 and Pen a 1 levels may indicate that the determination of just one of the above is reasonable.

Association of HLA-DQ and IL13 gene variants with challenge-proven shrimp allergy in West Bengal, India

Little is known about genetic factors and mechanisms underlying shrimp allergy. Genome-wide association studies identified HLA class-II and IL13 genes as highly plausible candidates for shrimp allergy. The present study was designed to investigate potential associations of HLA-DQ rs9275596, IL13 rs20541, and IL13 rs1800925 polymorphisms with challenge-proven shrimp allergy using the data from 532 people of West Bengal, India; selected on basis of positive skin prick test, elevated specific IgE and medical history. Risk genotypes, i.e., HLA-DQ rs9275596 CC, IL13 rs20541 AA, and IL13 rs1800925 TT, were found to be significantly associated with challenge positive shrimp allergy (P = 0.04, 0.01, and 0.03, respectively). Distribution of genotypes for HLA-DQ and IL13 polymorphisms in allergic and control subjects showed significant difference between younger (20-40 years) and older (> 40 years) age group (P = 0.006). Risk genotypes significantly associated with elevated shrimp-specific IgE. IL13 TA haplotype significantly associated with shrimp allergy and elevated specific IgE (P = 0.02). Synergistic effect of IL13 TA haplotype-HLA-DQ rs9275596 CC genotype interaction significantly elevated specific IgE (P = 0.03). The present study suggests that HLA-DQ and IL13 polymorphisms pose major risk for shrimp allergic patients in West Bengal, India and thus could be helpful for early target-specific therapeutic intervention in near future.

Overcoming Shellfish Allergy: How Far Have We Come?

Shellfish allergy caused by undesirable immunological responses upon ingestion of crustaceans and mollusks is a common cause of food allergy, especially in the Asia-Pacific region. While the prevalence of shellfish allergy is increasing, the mainstay of clinical diagnosis for these patients includes extract-based skin prick test and specific IgE measurement while clinical management consists of food avoidance and as-needed use of adrenaline autoinjector should they develop severe allergic reactions. Such a standard of care is unsatisfactory to both patients and healthcare practitioners. There is a pressing need to introduce more specific diagnostic methods, as well as effective and safe therapies for patients with shellfish allergy. Knowledge gained on the identifications and defining the immuno-molecular features of different shellfish allergens over the past two decades have gradually translated into the design of new diagnostic and treatment options for shellfish allergy. In this review, we will discuss the epidemiology, the molecular identification of shellfish allergens, recent progress in various diagnostic methods, as well as current development in immunotherapeutic approaches including the use of unmodified allergens, hypoallergens, immunoregulatory peptides and DNA vaccines for the prevention and treatment of shellfish allergy. The prospect of a “cure “for shellfish allergy is within reach.

Seafood-borne parasites in Australia: human health risks, fact or fiction?

Seafood is an increasingly popular source of healthy protein. Since 1961, the average annual increase in global food fish consumption has been twice as high as population growth and exceeds the consumption of meat from all terrestrial animals combined1. The following overview of seafood safety concerns is intended to help readers to understand potential risks associated with parasites in seafood products and the need for a national approach to reduce or minimise them. It is important to note that parasite infections are not limited to seafood: all other types of foods, including vegetables and red meat can also be infected with a broad range of parasites, some of which are more dangerous than parasites in seafood. The main issue is lack of science based contemporaneous safety protocols which focus on seafood-borne parasites. As a result, in Australia regulatory control of parasites in seafood lags far behind other food sectors. Seafood safety is a broad topic. The focus of this article is on an understudied field in Australia, seafood-borne parasitic diseases. The word ‘seafood' in this context encompasses fish and shellfish products from marine and freshwater ecosystems that are, directly or indirectly, meant for human consumption.

Hypersensitive adverse drug reactions to glucosamine and chondroitin preparations in Australia between 2000 and 2011

Purpose of the study

This study investigates spontaneous adverse drug reactions (ADRs) to glucosamine and chondroitin in the Australian population between 2000 and 2011, with a primary focus on hypersensitivity reactions.

Study design

Case reports of ADR to glucosamine and chondroitin sent to the Therapeutic Goods Administration between 2000 and 2011 were obtained and analysed. The demographic information and severity of the ADR were recorded for individual ADR cases. These reactions were classified according to the Brown et al grading system for generalised hypersensitivity reactions. This included mild hypersensitivity reactions (generalised erythema, urticaria and angioedema) through to moderate hypersensitivity reactions (wheeze, nausea, vomiting, dizziness (presyncope), diaphoresis, chest or throat tightness and abdominal pain), and more severe reactions (hypotension, confusion and collapse).

Results

In this study of 366 ADRs to glucosamine and chondroitin preparations, 71.85% of cases (n=263) were found to have hypersensitivity reactions. Of these 263 cases, 92 cases were classified as mild (eg, pruritus, urticaria and lip oedema), 128 cases classified as moderate (such as dyspnoea, nausea and abdominal pain), and 43 cases classified as severe (including amnesia, gait disturbance, somnolence and hypotension). It is not clear whether the patients involved had a known shellfish allergy or underlying atopy.

Conclusion

Results of this investigation support the need for clear labelling on glucosamine and chondroitin preparations to raise awareness of possible adverse events for those predisposed to allergy or atopy in response to shellfish.

Retrospective Study of Reported Adverse Events Due to Complementary Health Products in Singapore From 2010 to 2016

The objective of this study is to collate and analyse adverse event reports associated with the use of complementary health products (CHP) submitted to the Health Sciences Authority (HSA) of Singapore for the period 2010–2016 to identify various trends and signals for pharmacovigilance purposes. A total of 147,215 adverse event reports suspected to be associated with pharmaceutical products and CHP were received by HSA between 2010 and 2016. Of these, 143,191 (97.3%) were associated with chemical drugs, 1,807 (1.2%) with vaccines, 1,324 (0.9%) with biological drugs (biologics), and 893 (0.6%) with CHP. The number of adverse event reports associated with Chinese Proprietary Medicine, other complementary medicine and health supplements are presented. Eight hundred and ninety three adverse event reports associated with CHP in the 7-year period have been successfully collated and analyzed. In agreement with other studies, adverse events related to the “skin and appendages disorders” were the most commonly reported. Most of the cases involved dermal allergies (e.g., rashes) associated with the use of glucosamine products and most of the adulterated products were associated with the illegal addition of undeclared drugs for pain relief. Dexamethasone, chlorpheniramine, and piroxicam were the most common adulterants detected. Reporting suspected adverse events is strongly encouraged even if the causality is not confirmed because any signs of clustering will allow rapid regulatory actions to be taken. The findings from this study help to create greater awareness on the health risks, albeit low, when consuming CHP and dispelling the common misconception that “natural” means “safe.” In particular, healthcare professionals and the general public should be aware of potential adulteration of CHP. The analysis of spontaneously reported adverse events is an important surveillance system in monitoring the safety of CHP and helps in the understanding of the risk associated with the use of such products. Greater collaboration and communication between healthcare professionals, regulators, patients, manufacturers, researchers, and the general public are important to ensure the quality and safety of CHP.

Patterns of sensitization to inhalant and food allergens among pediatric patients from the Moscow region (Russian Federation)

The immunological profiles of human specific IgE (sIgE) and specific IgG4 (sIgG4) vary by genetic predisposition, living conditions in different geographical locations and patient’s age. The aim of our study was to analyze sIgE and sIgG4 patterns and their age-dependent changes in patients from the Moscow region. For identifying sIgE and sIgG4 profiles the blood samples from 513 patients aged 6 months to 17 years who were showing symptoms of allergic diseases were analyzed using microarrays containing 31 allergens. The highest sIgE prevalence was observed for birch pollen (32%) among pollen allergens, cat dander (24%) among indoor allergens, and egg whites (21%) among food allergens. The most common sIgG4 response was developed toward egg whites (80% of patients). Age-related elevation was identified for patients with increased sIgE to pollen allergens and indoor allergens (cat or dog dander and house dust mites). For each allergen, the proportion of cases with significant levels of sIgG4 appeared to increase with patients’ age. The data on allergen-specific sIgE and sIgG4 prevalence show both general trends and some local special aspects that are indicative for the Moscow region. This information should be useful in terms of epidemiology of allergic diseases.

Bifidobacterium infantis Potentially Alleviates Shrimp Tropomyosin-Induced Allergy by Tolerogenic Dendritic Cell-Dependent Induction of Regulatory T Cells and Alterations in Gut Microbiota

Shellfish is one of the major allergen sources worldwide, and tropomyosin (Tm) is the predominant allergic protein in shellfish. Probiotics has been appreciated for its beneficial effects on the host, including anti-allergic and anti-inflammatory effects, although the underlying mechanisms were not fully understood. In this study, oral administration of probiotic strain Bifidobacterium infantis 14.518 (Binf) effectively suppressed Tm-induced allergic response in a mouse model by both preventive and therapeutic strategies. Further results showed that Binf stimulated dendritic cells (DCs) maturation and CD103⁺ tolerogenic DCs accumulation in gut-associated lymphoid tissue, which subsequently induced regulatory T cells differentiation for suppressing Th2-biased response. We also found that Binf regulates the alterations of gut microbiota composition. Specifically, the increase of Dorea and decrease of Ralstonia is highly correlated with Th2/Treg ratio and may contribute to alleviating Tm-induced allergic responses. Our findings provide molecular insight into the application of Binf in alleviating food allergy and even gut immune homeostasis.

Allergen Sensitization Pattern by Sex: A Cluster Analysis in Korea

Background

Allergens tend to sensitize simultaneously. Etiology of this phenomenon has been suggested to be allergen cross-reactivity or concurrent exposure. However, little is known about specific allergen sensitization patterns.

Objective

To investigate the allergen sensitization characteristics according to gender.

Methods

Multiple allergen simultaneous test (MAST) is widely used as a screening tool for detecting allergen sensitization in dermatologic clinics. We retrospectively reviewed the medical records of patients with MAST results between 2008 and 2014 in our Department of Dermatology. A cluster analysis was performed to elucidate the allergen-specific immunoglobulin (Ig)E cluster pattern.

Results

The results of MAST (39 allergen-specific IgEs) from 4,360 cases were analyzed. By cluster analysis, 39items were grouped into 8 clusters. Each cluster had characteristic features. When compared with female, the male group tended to be sensitized more frequently to all tested allergens, except for fungus allergens cluster.

Conclusion

The cluster and comparative analysis results demonstrate that the allergen sensitization is clustered, manifesting allergen similarity or co-exposure. Only the fungus cluster allergens tend to sensitize female group more frequently than male group.

Allergens involved in the cross-reactivity of Aedes aegypti with other arthropods

BACKGROUND

Cross-reactivity between Aedes aegypti and mites, cockroaches, and shrimp has been previously suggested, but the involved molecular components have not been fully described.

OBJECTIVE

To evaluate the cross-reactivity between A aegypti and other arthropods.

METHODS

Thirty-four serum samples from patients with asthma and/or allergic rhinitis were selected, and specific IgE to A aegypti, Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia tropicalis, Periplaneta americana. and Litopenaeus vannamei was measured by enzyme-linked immunosorbent assay. Cross-reactivity was investigated using pooled serum samples from allergic patients, allergenic extracts, and the recombinant tropomyosins (Aed a 10.0201, Der p 10, Blo t 10, Lit v 1, and Per a 7). Four IgE reactive bands were further characterized by matrix-assisted laser desorption/ionization tandem time of flight.

RESULTS

Frequency of positive IgE reactivity was 82.35% to at least one mite species, 64.7% to A aegypti, 29.4% to P americana, and 23.5% to L vannamei. The highest IgE cross-reactivity was seen between A aegypti and D pteronyssinus (96.6%) followed by L vannamei (95.4%), B tropicalis (84.4%), and P americana (75.4%). Recombinant tropomyosins from mites, cockroach, or shrimp inhibited the IgE reactivity to the mosquito at a lower extent than the extracts from these arthropods. Several bands of A aegypti cross-reacted with arthropod extracts, and 4 of them were identified as odorant binding protein, mitochondrial cytochrome C, peptidyl-prolyl cis-trans isomerase, and protein with hypothetical magnesium ion binding function.

CONCLUSION

We identified 4 novel cross-reactive allergens in A aegypti allergenic extract. These molecules could influence the manifestation of allergy to environmental allergens in the tropics.

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.

Tropomyosin, the major tropical oyster Crassostrea belcheri allergen and effect of cooking on its allergenicity

BACKGROUND

Many types of shellfish including oysters are sometime cooked before ingestion and it has been demonstrated that cooking may affect the allergenicity of food. Therefore, the aim of our present study is to identify major and minor allergens of tropical oyster (Crassostrea belcheri) and to investigate the effect of different cooking processing on the allergenicity of this oyster.

METHODS

Raw, boiled, fried and roasted extracts of oyster were prepared. Protein profiles were analysed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Major and minor allergens and allergenicity patterns of all extracts were then determined by immunoblotting with sera from patients with positive skin prick tests (SPT) to the raw oyster extract. Mass-spectrometry was used to identify the major allergenic proteins of this oyster.

RESULTS

SDS-PAGE of the raw extract showed 15 protein bands (20-180 kDa). In contrast, smaller numbers of protein bands were demonstrated in the boiled extract, those ranging between 40-42 and 55-150 kDa were denatured, whereas the protein profiles were altered to a similar degree by frying or roasting. The 37 kDa proteins had the highest frequency of IgE-binding (95 %), thus identified as the major allergen of this tropical oyster. Other minor IgE-binding proteins were observed at various molecular weights. Immunoblot of raw extract yielded 11 IgE-binding proteins. The cooked extracts showed only a single IgE-binding protein at 37 kDa. Mass spectrometry analysis of the 37 kDa major allergen identified this spot as tropomyosin.

CONCLUSIONS

Cooked extracts produce lower IgE-binding than raw extract, which suggest that thermal treatment can be used as a tool in attempting to reduce oyster allergenicity by reducing the number of IgE-reactive bands. The degree of allergenicity of this oyster was demonstrated in the order raw > boiled > fried ≈ roasted. A heat-resistent 37 kDa protein, corresponding to tropomyosin, was identified as the major allergen of this tropical oyster.

Tropomyosin and Actin Identified as Major Allergens of the Carpet Clam (Paphia textile) and the Effect of Cooking on Their Allergenicity

OBJECTIVES

To identify the major allergenic proteins of clam (Paphia textile) and to investigate the effect of different cooking methods on the allergenicity of these identified proteins.

METHODS

Clam protein extracts were separated by denaturing polyacrylamide gel electrophoresis. IgE reactive proteins were then analyzed by immunoblotting with sera from patients with positive skin prick tests (SPT) to the raw clam extract. Mass spectrometry was used to identify the major allergenic proteins of this clam.

RESULTS

Raw extract showed 12 protein bands (18-150 kDa). In contrast, fewer protein bands were seen in the boiled extract; those ranging from 40 to 150 kDa were denatured. The protein profiles were similarly altered by frying or roasting. The immunoblots of raw and boiled extracts yielded 10 and 2 IgE-binding proteins, respectively. The fried and roasted extracts showed only a single IgE-binding protein at 37 kDa. Mass spectrometry analysis of the 37 and 42 kDa major allergens indicated that these spots were tropomyosin and actin, respectively.

CONCLUSION

The two major allergens of Paphia textile were identified as the thermostable tropomyosin and a new thermolabile allergen actin.

Cross-reactivity between aeroallergens and food allergens

In patients with respiratory allergy, cross-reactivity between aeroallergens and foods may induce food allergy, symptoms ranging from oral allergy syndrome to severe anaphylaxis. Clinical entities due to IgE sensitization to cross-reactive aeroallergen and food allergen components are described for many sources of plant origin (pollen-food syndromes and associations, such as birch-apple, cypress-peach and celery-mugwort-spice syndromes, and mugwort-peach, mugwort-chamomile, mugwort-mustard, ragweed-melon-banana, goosefoot-melon associations), fungal origin (Alternaria-spinach syndrome), and invertebrate, mammalian or avian origin (mite-shrimp, cat-pork, and bird-egg syndromes). Clinical cases of allergic reactions to ingestion of food products containing pollen grains of specific plants, in patients with respiratory allergy to Asteraceae pollen, especially mugwort and ragweed, are also mentioned, for honey, royal jelly and bee polen dietary supplements, along with allergic reactions to foods contaminated with mites or fungi in patients with respiratory allergy to these aeroallergens. Medical history and diagnosis approach may be guided by the knowledge about the diverse cross-reacting allergens involved, and by the understanding of these clinical entities which may vary significantly or may be overlapping. The association between primary IgE sensitization with respiratory symptoms to inhaled allergens and food allergy due to cross-reactive allergen components is important to assess in allergy practice. The use of molecular-based diagnosis improves the understanding of clinically relevant IgE sensitization to cross-reactive allergen components from aeroallergen sources and foods.

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.

Shellfish allergy and relation to iodinated contrast media: United Kingdom survey

AIM

To assess current practice of United Kingdom cardiologists with respect to patients with reported shellfish/iodine allergy, and in particular the use of iodinated contrast for elective coronary angiography. Moreover we have reviewed the current evidence-base and guidelines available in this area.

METHODS

A questionnaire survey was send to 500 senior United Kingdom cardiologists (almost 50% cardiologists registered with British Cardiovascular Society) using email and first 100 responses used to analyze practise. We involved cardiologists performing coronary angiograms routinely both at secondary and tertiary centres. Three specific questions relating to allergy were asked: (1) History of shellfish/iodine allergy in pre-angiography assessment; (2) Treatments offered for shellfish/iodine allergy individuals; and (3) Any specific treatment protocol for shellfish/iodine allergy cases. We aimed to establish routine practice in United Kingdom for patients undergoing elective coronary angiography. We also performed comprehensive PubMed search for the available evidence of relationship between shellfish/iodine allergy and contrast media.

RESULTS

A total of 100 responses were received, representing 20% of all United Kingdom cardiologists. Ninety-three replies were received from consultant cardiologists, 4 from non-consultant grades and 3 from cardiology specialist nurses. Amongst the respondents, 66% routinely asked about a previous history of shellfish/iodine allergy. Fifty-six percent would pre-treat these patients with steroids and anti-histamines. The other 44% do nothing, or do nonspecific testing based on their personal experience as following: (1) Skin test with 1 mL of subcutaneous contrast before intravenous contrast; (2) Test dose 2 mL contrast before coronary injection; (3) Close observation for shellfish allergy patients; and (4) Minimal evidence that the steroid and anti-histamine regime is effective but it makes us feel better.

CONCLUSION

There is no evidence that allergy to shellfish alters the risk of reaction to intravenous contrast more than any other allergy and asking about such allergies in pre-angiogram assessment will not provide any additional information except propagating the myth.