D2.289 - Independent Sensitization to Poultry and Fish in a Young Adult

Allergy to both poultry meat and fish is uncommon, and distinguishing cross-reactivity from independent sensitizations requires detailed molecular analysis.

We report the case of an 18-year-old male with recurrent anaphylactic reactions to chicken, turkey, duck, and salmon. The patient remained asymptomatic after eliminating poultry and salmon from his diet. He tolerated other fish. Skin prick testing showed positivity to chicken, salmon, hake and shrimp, while ALEX² and ImmunoCAP testing revealed sensitization to parvalbumins and tropomyosin. A comprehensive protein-level study was undertaken to identify the allergenic molecules responsible.

Protein extracts from raw and cooked chicken, salmon, hake and shrimp were prepared using validated extraction protocols, followed by filtration, lyophilization and Bradford quantification. SDS-PAGE and IgE–Western blot were performed under reducing conditions. An inhibition Western blot was conducted using cooked chicken as the solid phase to evaluate potential cross-reactivity between poultry and fish allergens, as described in the literature.

The IgE–Western blot revealed low-intensity bands of 36 and 40 kDa in raw chicken, with the 40 kDa band consistent with aldolase, and additional 25 and 15 kDa bands in cooked chicken, the latter compatible with parvalbumin. Both raw and cooked chicken showed a 50 kDa band consistent with β-enolase Gal d 9. Salmon extracts presented a 12 kDa band with stronger intensity in cooked samples, corresponding to the known β-parvalbumin Sal s 1. Raw hake displayed a faint ~12 kDa band, again compatible with β-parvalbumin. Shrimp extracts demonstrated IgE binding at 35 kDa and 22 kDa under both conditions, the 35 kDa band corresponding to tropomyosin Pen a 1. The inhibition Western blot using cooked chicken as the solid phase showed no reduction in IgE binding when inhibited with extracts of salmon, cooked salmon, raw hake, raw shrimp or cooked shrimp, indicating absence of cross-reactivity and confirming independent sensitization to chicken, fish and shrimp proteins.

This case demonstrates independent sensitization to multiple animal protein sources, with clinically relevant allergens including chicken aldolase and β-enolase and fish β-parvalbumins. The patient tolerates shellfish. The absence of cross-inhibition confirms that the patient’s reactions are due to co-sensitization rather than shared epitopes. IgE–Western blot proved essential in resolving the diagnostic complexity and identifying the specific molecules implicated in both poultry and fish allergy.