So far, the general recommendation for those with a fish allergy has been to completely abstain from eating fish. Now however, an international research team, including Dr Annette Kühn and Prof Markus Ollert from LIH’s Department of Infection and Immunity and Dr Martin Sørensen from the University Hospital of North Norway in Tromsø, has proven that someone who is allergic to fish does not necessarily have to completely avoid this healthy diet.

Fish is an important source of digestible protein and provides the body with iodine and essential omega-3 fatty acids. Yet, fish is one of the foods to which many people develop a life-long food allergy with mild to severe symptoms. Worldwide, an estimated 0.1 to 4% of the population suffers from an allergy to fish. Some allergic patients can tolerate certain varieties of fish and so, despite their hypersensitivity, could still enjoy this valuable source of dietary protein.

In the new study, the research team gave cod, salmon and mackerel to 35 patients with a proven fish allergy and then measured IgE antibodies against fish allergens in their blood. The scientists determined that fish allergic patients produce differential antibodies depending on whether their hypersensitivity is to parvalbumin alone, the allergen to which most people allergic to fish react, or also to enolase and aldolase, that were identified as allergens in a previous study from the research group at LIH. Dr Kühn and colleagues have thus proven for the first time that it is possible to stratify patients according to their cross-allergy to several types of fish.

‘We showed that about one third of the fish allergic patients tolerated specific types of fish,’ says Dr Kühn. ‘The antibodies  we identifed serve as markers by which it is possible to distinguish between those allergic to only one type of fish and those allergic to several fish species.’ ‘This is important to avoid unnecessary restrictions of healthy food, especially for allergic children, who very often have multiple food allergies’ adds Dr Sørensen.

The scientists published these results in the October issue of the worldwide most important scientific journal for allergic diseases, the “Journal of Allergy and Clinical Immunology”.  ‘The research done in Luxembourg has been most valuable. Without LIH’s expertise in molecular allergology, it would not have been possible to perform the study’, stresses Dr Sørensen. This form of clinically-oriented translational allergy research opens up entirely new possibilities for molecular and personalised allergy diagnosis.

A related press release is available in French and German.

Link to publication: Cross-reactivity in fish allergy: A double-blind, placebo-controlled food-challenge trial