The Application of Basophil Activation Test in Seafood Allergy Diagnosis: The Preliminary Results

The basophil activation test (BAT) evaluates the basophil activation upon exposure to an allergen through the increased expression of CD63 and CD203c. Because allergens can induce basophil activation by cross-linking specific IgE, the elevated CD63 and CD203c expressions have been proposed as a novel in vitro test for the specific IgE-induced immediate allergy. However, the research on BAT in diagnosing food allergy is still limited in Vietnam. In this study, fifteen patients with a history of shellfish allergy were recruited. Skin prick tests (SPT) were performed with seafood allergens extracted from different scrimps and crabs. Fifteen ml of whole blood was collected. The allergen-specific IgE was determined by immunoblot using EUROLINE (EUROIMMUN, Germany). Basophils were incubated with allergens, anti-IgE antibody, and respective antibodies of BAT. By using flow cytometry, basophils were defined as CD123+/HLA-DR- in the lymphocyte subset, and the activated basophils were defined as CD63+ or CD203c+ basophils. Allergens were extracted from giant prawn (Macrobrachium rosenbergii), prawn (Penaeus monodon), white leg shrimp (Litopenaeus vannamei), giant mud crab (Somanniathelphusa sinensis), seawater crab (Scylla paramamosain), sardine (Sardina pilchardus). Among the patients, 10/15(66,7%) patients had increased levels of CD63 or CD203c, there were 5/10 (50%) patients expressed CD63+ and CD203c+, 4/15 (26,7%) patients expressed CD203+ and 1/15 (6,7%) case showed CD63+ only. Moreover, there was a positive correlation between SPT, levels of allergen-specific IgE, and CD63+ CD203+ expression. In conclusion, the CD63 and CD203c-based BAT is potential for diagnosis of seafood allergy in addition to SPT or allergen-specific IgE.