The proteins that can lead to fish allergies and intolerances may be much more species-specific than previously assumed, according to new research.
Writing in the Journal of Investigational Allergology and Clinical Immunology (JIACI), the German research team behind the study report on the case of participants with a specific allergy to Nile perch but not cod, revealing species-specific allergens that could help to improve avoidance strategies against such food allergies and may help to make them more specific.
Led by Dr. Janina Tomm from Helmholtz Centre for Environmental Research (UFZ), the research team commented that the globalisation of the food industry has led to widespread exposure to new non-domestic fish species, which in turn has led to the need to identify new and more specific fish allergens.
"The tests that are currently used are very non-specific," explained Tomm. "For some people who suffer from fish allergies there may be hope of finding a fish that they can tolerate if we managed to make the relevant tests suitable for mass implementation and use them in allergy diagnostics."
Tomm and her colleagues explained that the most direct way of identifying new allergens is through analysing the serum of affected patients and the proteins of the allergy source - if the IgE antibodies in the patients' serum bind to the proteins of the food that triggers the allergy, there is a clear signal of allergy.
The newly identified allergies can initially be used for individual diagnoses, and may also be useful later for epidemiological studies which aim to determine the relevance of individual allergies, the team added.
In the new study, Tomm and her team examined two patients from the University Hospital Leipzig and ten from the Haukeland University Hospital in Bergen in Norway. One of the subjects was a 24-year-old chef from Leipzig who had developed an allergy to Nile perch (Lates niloticus) after having come into contact with the raw fish following consumption of salmon (Salmo salar).
What was unusual about this case, they noted, was that the patient tolerated other types of fish.
Indeed, testing indicated signs of allergies to Nile perch and salmon, but not to Atlantic cod (Gadus morhua).
A second case involved the examination of proteins from the Kuruma shrimp (Marsupenaeus japonicus). The team identified two new enzymes, pyruvate kinase and phosphopyruvate hydratase, which they believe may be the cause of food allergies to shellfish.
"This shows us that even though we are significantly better at predicting allergies, computer algorithms can currently not replace biochemical experiments," said Professor Jan-Christoph Simon from the University of Leipzig.
Source: Journal of Investigational Allergology and Clinical Immunology
Volume 23, Number 3, Pages 159-167
"Identification of New Potential Allergens From Nile Perch (Lates niloticus) and Cod (Gadus morhua)"
Authors: JM Tomm, T van Do, C Jende, et al