Basophil Activation Test With Aspergillus Molecules: The Case for ABPA

Area of Science:

• Allergy and Immunology
• Pulmonology
• Diagnostic Biomarkers

Background:

• Allergic bronchopulmonary aspergillosis (ABPA) is an underdiagnosed allergic condition.
• Current diagnostic methods using IgE and IgG to Aspergillus fumigatus (AF) extracts struggle to differentiate sensitization from ABPA.
• There is a need for more precise diagnostic tools for ABPA.

Purpose of the Study:

• To assess the efficacy of cellular functional assays, specifically the basophil activation test (BAT), using both AF extract and molecular allergens for ABPA diagnosis.
• To determine if molecular allergens can improve the diagnostic performance of BAT in ABPA.

Main Methods:

• A prospective study involving 67 patients, including 6 with ABPA.
• Basophil activation test (BAT) was performed using AF extract in all patients.
• A subset of 12 patients underwent BAT with specific molecular AF allergens (Asp f 1, 2, 3, 4, and 6).

Main Results:

• BAT with AF extract demonstrated high sensitivity (100%) and good specificity (77.6%) for ABPA diagnosis with an optimized cutoff.
• In patients with positive BAT to AF, BAT using Asp f 4 showed significantly higher responses in ABPA patients compared to non-ABPA patients (mean stimulation index 10.56 vs. 1.24, p=0.0002).

Conclusions:

• Basophil activation test (BAT) using AF extract is a valuable potential biomarker for suspected ABPA.
• The diagnostic accuracy of BAT for ABPA can be enhanced by incorporating specific AF molecular allergens, with Asp f 4 showing particular promise.