Production of Allergen Extracts for Bivalve Allergy Diagnosis Using Skin Prick Test

Zailatul Hani Mohamad Yadzir, Rosmilah Misnan, Faizal Bakhtiar, Noormalin Abdullah, Hanisom Abdullah and Shahnaz Murad

Background: Whilst the consumption of bivalves is reasonably high in Malaysia, the frequency of allergy to this group of shellfish in the local population is largely unknown. The aim of this preliminary study was to produce bivalve allergen extracts and to investigate the frequency of bivalve sensitization among the local atopic population. Methods: Raw allergen extracts were prepared from 5 different species of bivalves. Their protein profiles were studied using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Results: In SDS-PAGE, the bivalve extracts demonstrated 10 to 23 protein bands. The five protein profiles varied considerably but most visible protein bands lay within 25-100 kDa. At the same time, fifty patients with a history of atopy were skin prick tested (SPT) with these raw extracts of bivalves. Of the 50 subjects, 13 (26%) had a positive SPT to at least one of the 5 bivalve extracts tested, 8 (61%) reacted to one bivalve extract while only one (8%) reacted to all 5 bivalve extracts. The frequency of skin test reactivity to Malaysian cockle was the highest at 22%, followed by Carpet clam, 12% and 4% to the other 3 bivalve extracts; Tropical oyster, Asian clam and Asian green mussel. Conclusion: This study showed that of the five different bivalve species, cockle was found to have the highest frequency in skin test reactivity. It appears that an individual, who is sensitized to a mite, is also likely to be sensitized to bivalves.