D2.78 - Comparative analysis of IgE reactivity to fish extracts versus beta-parvalbumin molecules in allergic patients

Fish allergy diagnosis heavily relies on identifying specific IgE (sIgE) to beta-parvalbumins, the major fish allergens. However, testing with whole fish extracts versus specific molecular components often yields discrepant results. This study aimed to evaluate and compare sIgE sensitization profiles to various fish extracts and their corresponding beta-parvalbumin molecules to optimize component-resolved diagnostics.

We analyzed sIgE sensitization frequencies and levels among allergic patients tested for both fish extracts (E) and specific beta-parvalbumin molecules (M). The diagnostic panel included Salmon (Sal s, Sal s 1), Mackerel (Sco s, Sco s 1), Herring (Clu h, Clu h 1), Carp (Cyp c 1), Tuna (Thu a, Thu a 1), and Cod (Gad m, Gad m 1).

Sensitization profiles varied significantly depending on the fish species. Carp beta-parvalbumin (Cyp c 1) showed the highest overall sensitization rate (55.0%). The prevalence of sensitization to the molecular component was markedly higher than to the corresponding extract for Cod (Gad m 1: 52.2% vs Gad m: 38.9%) and Salmon (Sal s 1: 45.2% vs Sal s: 23.1%). In contrast, no statistically significant differences were observed between extract and molecule sensitization rates for Tuna (Thu a: 5.7% vs Thu a 1: 6.2%) and Herring (Clu h: 1.7% vs Clu h 1: 4.5%). Notably, a reversed pattern was identified for Mackerel, where sensitization to the whole extract prevailed over the specific beta-parvalbumin molecule (Sco s: 12.1% vs Sco s 1: 8.5%).

While testing for specific beta-parvalbumin molecules offers higher diagnostic sensitivity for species like cod and salmon, notable exceptions exist. The lack of significant differences for tuna and herring, alongside the reversed pattern seen in mackerel, may be attributed to naturally lower beta-parvalbumin content in certain pelagic fish muscles, as well as the presence of other currently uninvestigated allergenic molecules in the extracts. Therefore, a combined diagnostic approach remains optimal