D1.40 - Independent Sensitization to poultry meat and tuna in a food allergic young girl

Introduction

Poultry meat allergy is a rarefood allergy and may occur as a primary sensitization, with chicken being responsible for most reported reactions. Cross-reactive allergens shared between poultry meat and fish, including parvalbumins, enolases and aldolases, have been described and may complicate the diagnostic approach.We report a complex case of food allergy, where investigation into fish and chicken meat allergy is carried out.

Case Report

A 23-year-old woman with a personal history of mild atopic eczema reported immediate allergic reactions after ingestion of chicken meat and canned tuna. Symptoms occurred within 10–20 minutes and included oropharyngeal pruritus, urticaria, angioedema, gastrointestinal symptoms and occasional respiratory involvement. She tolerated egg and other fish species. Skin-prick tests and prick-to-prick tests were negative for all fish tested except canned tuna. Poultry meat allergy (chicken, turkey and duck) was confirmed by skin testing, with specific IgE to chicken meat of 0.48 kU/L. Solid-phase allergen chip analysis (ImmunoCAP ISAC) showed negative results for nGal d 5 and rGad c 1. Protein extracts from raw and cooked chicken, tuna, trout and salmon were prepared using standardized phosphate-buffered saline extraction. Protein profiles and IgE-binding patterns were analyzed by SDS-PAGE and IgE Western blot under reducing conditions, followed by IgE inhibition assays. Distinct protein patterns were observed across species and processing conditions. IgE Western blot revealed a clear IgE-reactive band in cooked chicken extracts in the 37–50 kDa range, compatible with the heat-stable allergen Gal d 6, and a separate IgE-reactive band of similar molecular weight in raw tuna extracts, compatible with the thermolabile allergen Thu a 3 (aldolase A). No IgE binding was observed to trout or salmon. Inhibition assays excluded cross-reactivity between chicken and tuna proteins.

Conclusions

This case demonstrates independent IgE-mediated sensitization to poultry meat and tuna, mediated by distinct allergenic proteins despite similar molecular weights. Immunochemical techniques were crucial to exclude cross-reactivity and to establish an accurate diagnosis, allowing safe inclusion of other fish species and targeted dietary avoidance of poultry meat and tuna.