Basophil activation test based on the expression of CD203c in the diagnostics of cow milk allergy in children

BACKGROUND: Detection of allergen-induced basophil activation by flow cytometry has been shown to be a useful tool for allergy diagnosis. OBJECTIVE: The aim of this study was to assess the potential of this technique for the diagnosis of pediatric cow milk allergy. MATERIAL AND METHODS: The quantification of total and specific IgE and basophil activation test were performed to evaluate cow milk allergic (n = 9), and non-allergic children (n = 15). RESULTS: Allergen-induced basophil activation was detected as a CD203c up-regulation. The expression of CD203c antigen on basophils was measured with flow cytometry. The antigen CD203c was detected on 15.4 ± 10.2% basophils from allergic children after incubation with specific allergens in concentration 1:10, whereas in the control group there were 3.0 ± 1.5% of basophils positive for this molecule (P < 0.05). Stimulation with allergen diluted 1:500 resulted in activation of 15.3 ± 11.2% of basophils in allergic children and 3.8 ± 2.3% of cells in the control group (P < 0.05). Positive results of an allergenicity test (above the cut- off level of 10%) were obtained in 7 out of the 9 allergic children. In 5 cases, the cutoff level was reached with both dilution of allergens (1:10 and 1:500). In 1 patient, positive stimulation was observed after stimulation with allergen diluted 1:10 and in another case only 1:500 resulted in stimulation of more then 10% of basophils. In no child of the control group, stimulation above 10% was noted. CONCLUSIONS: This study demonstrates that the analysis of allergen-induced CD203c up-regulation with flow cytometry is a reliable tool for the diagnosis of cow milk allergy in pediatric patients, with sensitivity similar to routine diagnostic tests and a higher specificity.