This is the first study using a multiplex technology to investigate IgE sensitizations to parvalbumins from 10 fish species, along with fish extracts from raw and heated fish material. Serum samples from 263 clinically well-defined fish allergic patients from a multinational cohort were analyzed regarding their sensitization patterns in a research version of the ALEX2 Allergy Xplorer.
• Up to 90% of the patients showed no IgE to parvalbumins and extracts from ray.
• Up to 21% tested negative for some bony fish species.
• Up to 38% were negative to cod parvalbumins, which is the most commonly used molecule in fish allergy diagnosis. Thus, this fish allergy marker may not be sufficient for accurate fish-allergy diagnosis.
• 17% tested negative to parvalbumins, but positive to the respective fish extracts, underlining the requirement for extracts for accurate diagnosis.
• Of the species analyzed, negativity to mackerel emerged as the best predictive marker of negativity to additional bony fish, such as herring or swordfish.
To conclude, this study demonstrates the need for extracts from both raw and heated fish and the parvalbumins from several evolutionary distant species for next-generation fish allergy diagnosis.