Allergens and molecular diagnostics of shellfish allergy

In recent years, there has been a steady growth in the production and consumption of shellfish due to its important role in human nutrition and health. This increased consumption has led to an increase in adverse health problems among consumers including immunoglobulin E (IgE)-mediated allergic reactions. Approximately 2 % of the world population is affected by shellfish allergy, which includes the crustacean and mollusk groups. The allergenic proteins present in the shellfish group have variable primary structures and often present a challenge in allergen detection and diagnosis. The distinction of crustacean from mollusk is important from clinical point of view, as molecular cross-reactivity, particularly between crustaceans, seems to be determined by the close relationship to insects and mites. 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 Ca++-binding protein. Other allergens include myosin light chain, troponin C, triose-phosphate isomerase, and actin. This chapter describes current information on shellfish allergy, the allergenic proteins involved, and diagnostic approaches

Problems with seafood: adverse reaction or true allergy?

[Extract] Allergies to foods affect up to 4% of adults and 8% of children and represent a significant public health concern throughout the world. About 90% of allergic reactions can be attributed to exposure to eight food groups including fish and crustaceans. Seafood allergies are particularly dangerous conditions as they are seldom outgrown and are associated with considerable morbidity and mortality. Seafood are one of the most important sources of proteins worldwide and currently already more than 30% of fish for human consumption comes from aquaculture. The number of people involved in fishing, farming and processing activities are well over 38 million. Increased consumption of seafood due to the promotion of a healthy diet and increased processing of seafood to meet consumption needs, has lead to more frequent reports of adverse reactions. A recent survey in the United States revealed that twice as many people have adverse reactions to seafood as compared to peanuts

Berufsallergien verursacht durch fisch und schalentiere: verbesserung der arbeitsbedingungen in der fisch- und meeresfrüchte-verarbeitenden industrie sind erforderlich / An overview of occupational allergy to fish and shellfish: towards improved management of seafood processing workers

Berufliche Allergie und beruflich erworbenes Asthma stellen schwerwiegende Erkrankungen dar und können auch Beschäftigte in der Fisch- und Meeresfrüchte-Industrie betreffen. Zu unterscheiden sind dabei zwei Hauptgruppen von Allergieauslösern: Fisch und Schalentiere (Krustentiere (Crustecea) und Weichtiere (Mollusken)). Für beide Gruppen wurden bereits einige allergene Proteine identifiziert, aber nur wenige wurden auf molekularer Ebene charakterisiert. Das Majorallergen der Fische scheint Parvalbumin zu sein, das der Krustentiere Tropomyosin. Neben weiteren IgE-bindenden Proteinen, die identifiziert wurden, fanden sich auch andere mit Meeresfrüchten bzw. Fischen assoziierte Bestandteile (z.B. Parasiten), deren molekularen Eigenschaften aber noch nicht im Detail beschrieben wurden. Luftgetragene Allergene von Fischen bzw. Meeresfrüchten können mit immunologischen und chemischen Methoden identifiziert werden, wobei eine Quantifizierung ab 10 ng/m³ möglich ist. Der folgende Artikel gibt einen Überblick über die industriellen Verarbeitungsprozesse von Fischen und Meeresfrüchten, die Tätigkeiten mit hohem Risiko sowie über persönliche und umweltbedingte Risikofaktoren für berufsbezogene Atemwegs- und Hautallergien in diesem Arbeitsbereich. Weiterhin werden die allergenen Proteine und die pathophysiologischen Mechanismen genauer beschrieben und darüber hinaus diagnostische und präventive Ansätze zum Management von arbeitsbedingten Allergien bei der Verarbeitung von Fisch und Meeresfrüchten vorgestellt. Occupational allergy and asthma are serious adverse health consequence affecting seafood-processing workers. Allergic reactions are directed to two major seafood groups: fish and shellfish, with the latter group comprising crustaceans and mollusks. Several allergenic proteins have been identified in these different groups, but few have been characterized on a molecular level. Parvalbumin appears to be the major fish allergen, while tropomyosin is the major crustacean allergen. Other IgE binding proteins have also been identified as well as other seafood-associated agents (e.q., parasites), although their molecular nature have not been characterized in detail. Aerosolized allergens can be identified and quantified using immunological and chemical approaches, detecting levels as low as 10 ng/m³. This review outlines the high-risk working populations, work processes, as well as host and environmental exposure risk factors for occupational respiratory and skin allergies. It also provides insights into the allergenic proteins as well as the pathophysiological mechanisms implicated. Diagnostic and preventive approaches are outlined in managing work-related allergy associated with seafood processing

Seafood processing in South Africa: a study of working practices, occupational health services and allergic health problems in the industry

The work practices, occupational health services and allergic health problems among workplaces which process seafood in Western Cape province of South Africa were examined. A cross-sectional study was conducted among 68 workplaces that were sent a self-administered postal survey questionnaire. Workplaces reporting a high prevalence of work-related symptoms associated with seafood exposure were also inspected. Forty-one (60%) workplaces responded to the questionnaire. The workforce consisted mainly of women (62%) and 31% were seasonal workers. Common seafoods processed were bony fish (76%) and rock lobster (34%). Major work processes involved freezing (71%), cutting (63%) and degutting (58%). Only 45% of workplaces provided an on-site occupational health service and 58% of workplaces conducted medical surveillance. Positive trends were observed between workplace size and activities such as occupational health service provision (P = 0.002), medical surveillance programmes (P = 0.055) and reporting work-related symptoms (P = 0.016). None of the workplaces had industrial hygiene surveillance programmes to evaluate the effects of exposure to seafood. Common work-related symptoms included skin rashes (78%), asthma (7%) and other non-specific allergies (15%). The annual prevalence of work-related skin symptoms reported per workplace was substantially higher for skin (0-100%) than for asthmatic (0-5%) symptoms. The relatively low prevalence of employer-reported asthmatic symptoms, when compared to epidemiological studies using direct investigator assessment of individual health status, suggests likely under-detection. This can be attributed to under-provision and under-development of occupational health surveillance programmes in workplaces with less than 200 workers. This is compounded further by the lack of specific statutory guidelines for the evaluation and control of bio-aerosols in South African workplaces

Occupational allergies in the seafood industry: a comparative study of Australian and South African workplaces

Although seafood allergy due to ingestion is commonly observed in clinical practice, the incidence of seafood allergies in general and more specifically in the occupational setting in Australia is largely unknown. The work practices, occupational health services and allergic health problems in 140 seafood processing workplaces in Australia were examined and compared to previous studies in South Africa. A cross-sectional employer-based survey design was used to conduct the study in both countries. In the South African study a response rate of 60% (n = 41) was obtained, compared to a response rate of 18% (n = 140) in Australia. The most common seafood processed by workplaces in South Africa was finfish (76%) and rock lobster (34%). Similarly in Australia, finfish (34%) was the most frequently handled seafood. However, processing of prawns (24%) and oysters (21%) was more common in Australia. Common work processes in South Africa involved freezing (71%), cutting/filleting (63%) and degutting (58%) procedures. Similar processes were followed in Australian industries with the exception of shucking of oysters, particularly common in the aquaculture industries. About half of the workplaces in both countries provided an occupational health service and medical surveillance of workers. However, none of the workplaces in South Africa and only 9% of the workplaces in Australia had industrial hygiene programs for seafood aerosols in place. In both countries positive trends were observed between the size of the workforce and the provision of occupational health services (p<0.005). Similarly, skin rash accounted for highest of all reported health problems (78-81%) followed by asthmatic symptoms (7-10%) and other non-specific allergic symptoms (9-15%) in both countries. Most workplaces reported the annual prevalence of work-related symptoms to be less than 5%. In Australia 7% of respondents in workplaces reported workers having left their workplace due to work-related allergic problems. Despite a low response rate of contacted companies in Australia, there were great similarities between the two countries suggesting that there is a significantly elevated prevalence of work related allergic symptoms in both countries. Unexpectedly, mollusc processing was more common in Australia although the occupational health related effects among exposed workers has previously not been investigated in detail and merits further study. It is recommended that further epidemiological studies focus on seafood exposure in Australia and identify specific risk factors for sensitisation

Differential requirements for interleukin (IL)-4 and IL-13 in protein contact dermatitis induced by Anisakis

Background:  Exposure to antigens of the fish parasite Anisakis is associated with the development of protein contact dermatitis in seafood-processing workers. Understanding the basic mechanisms controlling allergic sensitization through the skin is critical for designing therapies that will prevent the progression of allergic disease.\ud \ud Objective:  To investigate the roles of interleukin (IL)-4, IL-13 and the IL-4Rα in both local skin pathology and systemic sensitization following epicutaneous exposure to Anisakis proteins.\ud \ud Methods:  BALB/c wild-type (WT) mice and mice deficient in IL-4, IL-13 or IL-4 and IL-13, as well as mice with cell-specific impairment of IL-4Rα expression, were sensitized to Anisakis antigen by repeated epicutaneous application of Anisakis extract. Following this sensitization, skin pathology was recorded and systemic responses were investigated. Intravenous challenge with Anisakis extract was performed to test for the development of biologically relevant systemic sensitization.\ud \ud Results:  In WT mice, epicutaneous sensitization with Anisakis larval antigens induced localized inflammation, epidermal hyperplasia, production of TH2 cytokines, antigen-specific IgE and IgG1. Intravenous challenge of sensitized mice resulted in anaphylactic shock. Interestingly, IL-13 deficient mice failed to develop epidermal hyperplasia and inflammation, whilst anaphylaxis was reduced only in strains deficient either in IL-4 only, or deficient in IL-4 and IL-13 concurrently, as well as in mice deficient in IL-4Rα or with impaired IL-4Rα expression on CD4+ T cells.\ud \ud Conclusions:  Interleukin-13 plays a central role in protein contact dermatitis associated with repeated epicutaneous exposure to Anisakis extract, whereas IL-4 drives systemic sensitization and resultant anaphylactic shock

High concentrations of natural rubber latex allergens in gloves used by laboratory health personnel in South Africa

Introduction. Gloves made of natural rubber latex (NRL) are commonly used by healthcare workers because of their good qualities. However, allergic reactions to latex allergens are still commonly reported.\ud \ud Objective. To measure the concentrations of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens in gloves used by a large laboratory service in South Africa.\ud \ud Methods. NRL gloves as well as non-latex gloves supplied by various suppliers that were used by the laboratory personnel during the period June 2009 - May 2010 were obtained from various suppliers on the vendor list. Proteins were extracted from the gloves and Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens were quantified using the FITkit assay.\ud \ud Results. Twenty NRL gloves from 13 different brands were analysed. Only four (20%) of the 20 NRL gloves analysed had a total allergen content <0.15 μg/g, the suggested threshold limit for low allergenicity for the sum of these four allergens.\ud \ud Conclusion. This study demonstrated that a very low proportion of gloves tested had a total allergen content below the threshold for low allergenicity

Extract-Based and Molecular Diagnostics in Fish Allergy

Although fish is an elementary component of a healthy diet, it is also a food with high allergenic potential. In most cases, allergic reactions are induced by parvalbumins – small, stable proteins found in the muscle tissue. Many parvalbumin-positive individuals present with clinical reactions to various fish species, which can be explained through cross-reacting IgE antibodies. Thus far, complete fish extracts and two recombinant parvalbumins are available for IgE-based routine diagnostic procedures. Other important fish allergens are the enolases, the aldolases, and tropomyosin derived from fish muscle and vitellogenin from fish eggs, whose availability for diagnostics would allow more precise analysis of the sensitization profile of a fish-allergic patient. To date, there is no specific immunotherapy for fish allergy available. However, molecular biotechnological approaches have already led to the development of the first hypoallergenic molecules, which offer low-risk therapeutic prospects for the future

Novel way to study the function of native proteins in solution

Introduction: Aerosolisation of components when processing king crab (Paralithodes camtschaticus) and edible crab (Cancer pagurus) may cause occupational health problems when inhaled by workers. Methods: A cross-sectional study was carried out in three king crab plants and one edible crab plant. Personal exposure measurements were performed throughout work shifts. Air was collected for measurement of tropomyosin, total protein, endotoxin, trypsin and N-acetyl-β-D-glucosaminidase (NAGase). T-tests and ANOVAs were used to compare the levels of exposure in the different plants and areas in the plants. Results: Total protein and tropomyosin levels were highest in the edible crab plant, endotoxin levels were highest in king crab plants. King crab exposure levels were highest during raw processing. Tropomyosin levels were highest during raw king crab processing with geometric mean (GM) 9.6 ng/m3 vs 2.5 ng/m3 during cooked processing. Conversely, edible crab tropomyosin levels were highest during cooked processing with GM 45.4 ng/m3 vs 8.7 ng/m3 during raw processing. Endotoxin levels were higher in king crab plants than in the edible crab plant with GM=6285.5 endotoxin units (EU)/m3 vs 72 EU/m3. In the edible crab plant, NAGase levels were highest during raw processing with GM=853 pmol4- methylumbelliferone (MU)/m3 vs 422 pmol4-MU/m3 during cooked processing. Trypsin activity was found in both king crab and edible crab plants and levels were higher in raw than cooked processing. Differences in exposure levels between plants and worker groups (raw and cooked processing) were identified Conclusions: Norwegian crab processing workers are exposed to airborne proteins, tropomyosin, endotoxins, trypsin and NAGase in their breathing zone. Levels vary between worker groups and factories

High-speed videos of a mixed-flow centrifugal pump in gas-liquid flow (Data Supporting PhD Thesis: "The effect of gas on multi-stage mixed-flow centrifugal pumps")

These high speed videos of a 4-stage mixed-flow centrifugal pump show the different flow patterns observed in gas-liquid flows, depending on the inlet gas fraction and total flow rate. The pump rotates at 20 Hz and the acronym BEP stands for the design (or Best Efficiency Point) flow rate. The operating and shooting conditions are specified in more details in the Image file VideoTable.png and in PhD dissertation which these videos support