Heterogeneity in Allergy to Mollusks: A Clinical-Immunological Study in a Population From the North of Spain

Abstract

Background: Allergy to mollusks has been the focus of fewer studies than allergy to crustaceans. Furthermore, allergy to mollusks is less well characterized. Objectives: To describe the clinical characteristics of mollusk-allergic patients, to identify the responsible allergens, and to assess crossreactivity. Methods: We performed a prospective multicenter study including 45 patients with mollusk allergy, which was diagnosed based on a suggestive clinical history and a positive skin test result with the agent involved. Fractions were identified using SDS-PAGE and immunoblotting. The proteins responsible were subsequently identified using mass spectrometry. ELISA inhibition studies were performed with mollusks, dust mites, and crustaceans. Results: We found that 25 patients (55%) were allergic to cephalopods, 14 (31%) to bivalves, and 11 (24%) to gastropods. Limpet was the third most frequent cause of allergy (15% of cases). In 31 patients (69%), the manifestation was systemic; 10 (22%) exhibited oral allergy syndrome, and 7 (15%) experienced contact urticaria. Most major allergens were found between 27 kDa and 47 kDa. ELISA inhibition assays revealed a high degree of inhibition of cephalopods and bivalves from all the groups of mollusks, mites, and crustaceans. Mass spectrometry identified tropomyosin, actin, and myosin as the major allergens. Conclusions: Cephalopods, especially squid, are the mollusks that most frequently trigger allergic symptoms. The very frequent occurrence of allergy to limpets is striking, given their low consumption in our area. It is worth highlighting the heterogeneity observed, exemplified by the gastropods. Tropomyosin appears to be responsible for the high cross-reactivity found between mollusks, mites, and crustaceans. Three new mollusk allergens were also identified, namely, actin, enolase, and a putative C1q domain-containing protein.

Allergenicity assessment of Delonix regia pollen grain and identification of allergens by immunoproteomic approach

“…Spot no 6 was identified as actin, which is an essential component of cell cytoskeleton and participates in many important cellular processes, including cell motility, cell division, various plant cell signalling events etc. Actin was earlier reported as a major allergen from molluscs ( Mohamad-Yadzir et al., 2015 ; Azofra et al., 2017 ; González-Mancebo et al., 2019 ), which is recently reported as a cross-reactive allergen ( Barbarroja-Escudero et al., 2019 ). However, no report was available on the allergenic nature of this protein of plant origin.…”

IgE Mediated Shellfish Allergy in Children—A Review

“…Approximately 45% of individuals with a crustacean allergy are also allergic to mollusk, while 70–80% of mollusk-allergic patients also experienced allergic reactions to crustaceans [ 24 , 30 , 106 , 107 , 108 ]. Some patients may have species-specific shrimp allergy [ 44 , 109 ].…”

Mollusk allergy in shrimp-allergic patients: Still a complex diagnosis. An Italian real-life cross-sectional multicenter study

“…However, recent studies seem to suggest that this is not the case; in fact, a significant proportion of crustacean allergic patients report that they usually tolerate other invertebrates. 9 Both in vivo and in vitro diagnostics failure nowadays is caused in part by the poor quality of the extracts, and extract-based diagnostics can also be limited by cross-reactivity, failing to detect IgE crosslinking. 10,11 It has been widely demonstrated that diagnostics with commercially available shellfish extracts do not always lead to the correct identification of sensitized patients.…”