Advancing drug allergy diagnosis in Tunisia using flow cytometry: a promising first step

Background: Hypersensitivity reactions to drugs represent a significant and growing health concern worldwide, with the potential to cause severe and life-threatening outcomes. Accurate diagnosis of drug allergies is essential for effective patient management, particularly in differentiating true allergic reactions from other adverse drug reactions. Objective: This study aimed to evaluate for the first time the Basophil Activation Test (BAT) using flow cytometry as a reliable diagnostic tool for immediate-type drug allergies in Tunisia. Methods: This study included 35 BATs, conducted between November 2022 and December 2024. Only one patient underwent two separate BATs on different drugs. From each patient, venous blood was drawn and BAT was assessed using flow cytometry. Serial dilutions of suspected drugs, including antibiotics (e.g., amoxicillin and cefixime), non-steroidal anti-inflammatory drugs (e.g., mefenamic acid), and others, were tested. For each sample, basophils were incubated with the drug dilutions stained with antibodies marked with different fluorescents, such as CRTH2-FITC, CD3-PC7, CD203c-PE, and then analyzed on a Navios Ex flow cytometry. Results: Of all the performed BATs, antibiotics represented the majority of tested drugs accounting for 56%. However, only three tests were positive, in favor of a type I hypersensitivity drug reaction. Conclusion: By applying BAT in the Immunology Department of the Military Hospital of Tunisia, this study seeks to enhance diagnostic accuracy and contribute to personalized patient care.