Parvalbumins are the most important fish allergens. Polysensitization to various fish species is common and linked to the cross-reactivity of their parvalbumins.
Dark-muscled fish such as tuna may be less allergenic.
Total protein extracts and purified parvalbumins from cod, whiff, and swordfish were tested for IgE-binding properties with 16 fish-allergic patients' sera from Spain.
Parvalbumins levels from cod were 20 times higher than from swordfish (whiff 30 times higher).
Parvalbumins were recognized by 94% of the patients in extracts of cod and whiff, but only by 60% in swordfish extracts.
The parvalbumins of cod, whiff and swordfish are highly cross-reactive due to high amino acid sequence.
The low allergenicity of swordfish is due to the low expression levels of its parvalbumin.
Fish-allergic patients should avoid all fish species until a species can be proven safe to eat by provocative challenge (Annals of Allergy and Imm, 1999).
Expression levels of parvalbumins determine allergenicity of fish species. U. Griesmeier, S. Vázquez-Cortés, M. Bublin, C. Radauer, Y. Ma, P. Briza, M. Fernández-Rivas, H. Breiteneder. Allergy, 2009.
Epitope Mapping of Atlantic Salmon Major Allergen by Peptide Microarray Immunoassay http://goo.gl/OGCnn