D3.91 - Molecular Profiling of Shrimp Allergy in Tunisia: The Role of Tropomyosin and Component-Resolved Diagnosis

Shrimp allergy is an emerging public health issue in Tunisia, likely driven by changing dietary habits. This study aimed to assess the added value of component-resolved diagnosis (CRD) in the immunological characterization of shrimp allergy and in identifying clinically relevant cross-reactivity with house dust mites (HDMs) and snails.

Thirty-one patients with a self-reported history of shrimp allergy were evaluated at the Clinical Immunology Department of the Pasteur Institute of Tunis. Total IgE (tIgE) and specific IgE (sIgE) to shrimp, snail, HDMs, and recombinant allergens rPen a 1 and rDer p 10 were measured using ImmunoCAP®.

The population was predominantly young (mean age 15.5 years; male-to-female ratio 1.4). Oropharyngeal pruritus and urticaria were the most frequent symptoms. Shrimp allergy was confirmed in 54.8% of patients. Tropomyosin-specific sensitization (rPen a 1) was observed in 70.5% of shrimp-allergic patients. ROC curve analysis revealed that an rPen a 1 titer of 0.41 kUA/L optimally discriminated patients with positive shrimp-specific IgE, yielding 100% sensitivity and 100% specificity (AUC=1, p=0.005), indicating that patients above this threshold were reliably sensitized to tropomyosin. Cross-reactivity was identified in 58.8% of confirmed cases, mainly with snails. Total IgE levels and the shrimp sIgE/tIgE ratio were significantly higher in shrimp-allergic patients (p = 0.005). Multivariable analysis confirmed a central role of tropomyosin-driven sensitization and demonstrated strong predictive associations between rPen a 1, rDer p 10, and snail sIgE.

CRD highlights tropomyosin as the key molecular marker of shrimp allergy in Tunisia and enables accurate identification of cross-reactivity with HDMs and snails. Incorporating CRD into diagnostic algorithms may improve patient stratification and diagnostic precision.