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 cut-off 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.