Background: The diagnosis of immediate allergy is based on clinical data, skin prick tests (SPT), and measurements of allergen-specific IgE (sIgE). Basophil activation test (BAT) can supplement these methods and obviate their disadvantages, and possibly replace allergen challenge tests, such as a nasal provocative test (NPT). In this study, we assessed the influence of different storage times on BAT results. Futhermore, we compared the results of SPT, sIgE and NPT against BAT for common aeroallergens.
Methods: BAT was performed in twelve patients with allergic rhinitis sensitized to birch pollen or mites 1, 4 and 24 hours after blood sampling. CD63 was used as an activation marker. Three serial 10-fold dilutions (1:1, 1:10, 100) of allergen extract were employed. The further 10 individuals allergic to mites undergone complete diagnostic evaluation including SPT, sIgE measurements, NPT and BAT. Receiver operating characteristic (ROC) curves were used to compare the diagnostic techniques and tests conditions.
Results: Basophil activation expressed as stimulation index did not decline significantly up to 24h. Exposure to causal allergens resulted in a dose-dependent increase in expression of CD63 on peripheral blood basophils in tested individuals. We did not observed substantial differences in results of the investigated diagnostic methods determined by a ROC analysis.
Conclusions: Flow-assisted diagnosis of common respiratory allergy relies upon allergen-induced activation of blood basophils can be a useful approach to determine the clinically relevant allergen in sensitized individuals. BAT with inhaled allergens can be performed within 24 hours after blood collecting into a tube with EDTA. Allergen suitable for NPT in appropriate dilutions is a good reagent for use in BAT.