[The role of the basophil activation test (BAT) in qualification for specific immunotherapy with inhalant allergens].

Abstract

Qualification for specific immunotherapy (SIT) according to the guidelines of the European Academy of Allergy and Clinical Immunology (EAACI) includes medical history, skin prik tests (SPT) and/or measuring the concentration of sIgE. It is necessary to perform additional diagnostic tests in case of discrepancies between the history and the results of SPT/sIgE or differences between SPT and sIgE. Basophil activation test (BAT) assesses the expression of activation markers of these cells, eg. CD63 and CD203c after stimulation. The aim of our study was to evaluate the usefulness of BAT in the qualification for the SIT in comparison to the SPT and sIgE and in case of discrepancies between the results of SPT and sIgE. The study included 30 patients with allergic rhinitis (AR) caused by allergy to house dust mite (Dermatophagoides pteronyssinus, Dp) or birch pollen qualified for SIT. All patients had SPT, sIgE and BAT determination. The group of patients with allergy to birch was a control group for Dp allergic and vice versa. BAT with CD63 antigen expression was performed using a Flow2CAST test. Basophils were stimulated with allergen preparation (50, 500, and 5000 SBU/ml concentrations). BAT results were expressed as a stimulation index (SI). For optimal concentrations of 50 and 500 SBU/ml parameters comparing BAT to SPT and sIgE as the gold standards were consecutively: sensitivity 82-100% and 93-100%, specificity 50-94% and 47-89%, positive predictive value 65- 94% and 61-87%, negative predictive value 86-100% and 93-100%. Correlation BAT - SPT and BAT - sIgE ranged within 0.59 to 0.84 and 0.51 to 0.72. BAT was helpful in 2 of 30 patients with incompatible results of SPT and sIgE. Optimal concentrations for basophil stimulation are 50 and 500 SBU/ ml. BAT may be useful diagnostic tool in the qualification for the SIT in case of discrepancies between the results of SPT and sIgE.