Resolution of IgE-mediated fish allergy

Thermostable allergens in canned fish: Evaluating risks for fish allergy

BACKGROUND

Major fish allergens, including parvalbumin (PV), are heat stable and can withstand extensive cooking processes. Thus, the management of fish allergy generally relies on complete avoidance. Fish-allergic patients may be advised to consume canned fish, as some fish-allergic individuals have reported tolerance to canned fish. However, the safety of consuming canned fish has not been evaluated with comprehensive immunological and molecular analysis of canned fish products.

METHODS

We characterized the in vitro immunoreactivity of serum obtained from fish-allergic subjects to canned fish. Seventeen canned fish products (salmon n = 8; tuna n = 7; sardine n = 2) were assessed for the content and integrity of PV using allergen-specific antibodies. Subsequently, the sIgE binding of five selected products was evaluated for individual fish-allergic patients (n = 53). Finally, sIgE-binding proteins were identified by mass spectrometry.

RESULTS

The canned fish showed a markedly reduced PV content and binding to PV-specific antibodies compared with conventionally cooked fish. However, PV and other heat-stable fish allergens, including tropomyosin and collagen, still maintained their sIgE-binding capacity. Of 53 patients, 66% showed sIgE binding to canned fish proteins. The canned sardine contained proteins bound to sIgE from 51% of patients, followed by canned salmon (43%-45%) and tuna (8%-17%). PV was the major allergen in canned salmon and sardine. Tropomyosin and/or collagen also showed sIgE binding.

CONCLUSION

We showed that canned fish products may not be safe for all fish-allergic patients. Canned fish products should only be considered into the diet of individuals with fish allergy, after detailed evaluation which may include in vitro diagnostics to various heat-stable fish allergens and food challenge conducted in suitable environments.

Assessment of the effects of a work-related allergy to seafood on the reduction of earning capacity in the context of BK No. 5101

Fish, crustaceans, and mollusks are among the most potent allergenic foods of animal origin and are thus important triggers of work-related immediate-food allergies. In Germany, work-related seafood allergies are of great importance in the fishing and processing industries as well as in the areas of food preparation, food control, and food sales. There is no causal therapy of seafood allergy, only the strict and lifelong avoidance of allergens remains. The following recommendations serve to assess the impact of a seafood allergy with regard to the work opportunities ended by it for the assessment of the reduction of earning capacity (MdE (German for Minderung der Erwerbsfähigkeit)) in the context of the occupational disease number 5101 of the Annex to the German regulation for occupational diseases. As a special feature of work-related seafood allergy with regard to insurance law aspects, it must be taken into account that there is a potential risk of systemic reaction with subsequent multi-organ involvement. For the estimation of MdE in the general labor market, the impact of a seafood allergy can therefore be assessed, depending on its clinical severity, as generally “mild” to “severe” in justified individual cases.

[Seafood allergy in cooks: a case series and review of the literature]

BACKGROUND

Seafood is a very potent allergen. Epidemiological studies of seafood allergy in the highly exposed cooking profession are lacking. The objective of this first case series was to demonstrate the high relevance and consequences of seafood allergy in cooks. PATIENTS UND METHODS: Retrospective analysis of all the case files sent in which the presence of an occupational disease according to no. 5101 of the appendix of the German ordinance on industrial disease was to be clarified.

RESULTS

Thirty cooks (men 70 %) with an occupational seafood allergy were assessed between January 2008 and April 2014. Seafood allergy was observed in youngish workers(median age 24.7 yrs.) with an early manifestation of the disease (after 1.7 yrs. of occupation in median). In all except one (96.7 %) onset was localized on the hands.Most commonly documented were immediate sensitizations to cod, salmon, trout,and herring. Emergency treatment due to an anaphylactic shock at the workplace became necessary in 5 cases (16.7 %). In 27 cases (90 %) discontinuation of occupation was needed and was carried out after 6.3 yrs. of occupation in median.

CONCLUSIONS

Seafood allergy in cooks is mostly characterized by a quick progressive course of disease, already at the start of the cooking career. The prognosis for continuance in occupation is poor and an occupational disease is to be considered at a nearly stage. An emergency kit with an epinephrine auto-injector should be provided for life by the responsible accident insurer.

Fish allergens at a glance: variable allergenicity of parvalbumins, the major fish allergens

Fish is a common trigger of severe, food-allergic reactions. Only a limited number of proteins induce specific IgE-mediated immune reactions. The major fish allergens are the parvalbumins. They are members of the calcium-binding EF-hand protein family characterized by a conserved protein structure. They represent highly cross-reactive allergens for patients with specific IgE to conserved epitopes. These patients might experience clinical reactions with various fish species. On the other hand, some individuals have IgE antibodies directed against unique, species-specific parvalbumin epitopes, and these patients show clinical symptoms only with certain fish species. Furthermore, different parvalbumin isoforms and isoallergens are present in the same fish and might display variable allergenicity. This was shown for salmon homologs, where only a single parvalbumin (beta-1) isoform was identified as allergen in specific patients. In addition to the parvalbumins, several other fish proteins, enolases, aldolases, and fish gelatin, seem to be important allergens. New clinical and molecular insights advanced the knowledge and understanding of fish allergy in the last years. These findings were useful for the advancement of the IgE-based diagnosis and also for the management of fish allergies consisting of advice and treatment of fish-allergic patients.