Background: The basophil activation test (BAT) is an effective diagnostic tool in mold allergy, which is still not sufficiently known.
Objectives: The aim of our study was to assess the degree of annexin V binding to the surface of the basophil cell membrane after stimulation with anti-immunoglobulin E (anti-IgE) and Alternaria alternata allergenic extract.
Material and methods: Alternaria alternata allergic patients (n = 32) and healthy volunteers (n = 33) were evaluated using skin prick tests (SPT), quantification of specific IgE (sIgE) and the BAT. Basophil activation was detected as a percentage degree of annexin V binding to the surface of the basophil cell membrane.
Results: Receiver operating characteristic (ROC) curve analysis yielded a threshold value of 4.95% of activated basophils when the tested group and control group were studied, with a sensitivity and specificity of 100% (area under curve [AUC] = 1; p = 0.00000) for 100 SBU/mL Alternaria alternata allergen extract. The threshold value was 10.28% with a sensitivity of 93.8% and specificity of 100% (AUC = 0.98958; p = 0.00000) for 10 SBU/mL mold extract, and 9.37% with a sensitivity of 90.3% and specificity of 100% (AUC = 0.96307; p = 0.00000) for 1 SBU/mL Alternaria alternata allergen extract. The method was least efficacious in antiIgE stimulation, where the threshold value was 5.48% with a sensitivity of 90.6% and specificity of 30.3% (AUC = 0.46780; p = 0.67039).
Conclusions: The BAT with annexin V and sIgE measurement against Alternaria alternata increase the capability of a diagnostic laboratory for detecting mold sensitization. Both methods may certainly replace SPT, which are currently routinely used in allergy diagnosis. Annexin V may be considered a new basophil activation marker with an efficacy comparable to that of CD63 or CD203c.
Keywords: Alternaria alternata allergy; basophil activation test; flow cytometry; receiver operating characteristic curve; specific immunoglobulins E.