Basophil Reactivity as Biomarker in Immediate Drug Hypersensitivity Reactions—Potential and Limitations

Abstract

Immediate drug hypersensitivity reactions (DHRs) resemble typical immunoglobulin E (IgE)-mediated symptoms. Clinical manifestations range from local skin reactions, gastrointestinal and/or respiratory symptoms to severe systemic involvement with potential fatal outcome. Depending on the substance group of the eliciting drug the correct diagnosis is a major challenge. Skin testing and in vitro diagnostics are often unreliable and not reproducible. The involvement of drug-specific IgE is questionable in many cases. The culprit substance (parent drug or metabolite) and potential cross-reacting compounds are difficult to identify, patient history and drug provocation testing often remain the only means for diagnosis. Hence, several groups proposed basophil activation test (BAT) for the diagnosis of immediate DHRs as basophils are well-known effector cells in allergic reactions. However, the usefulness of BAT in immediate DHRs is highly variable and dependent on the drug itself plus its capacity to spontaneously conjugate to serum proteins. Stimulation with pure solutions of the parent drug or metabolites thereof vs. drug-protein conjugates may influence sensitivity and specificity of the test. We thus, reviewed the available literature about the use of BAT for diagnosing immediate DHRs against drug classes such as antibiotics, radio contrast media, neuromuscular blocking agents, non-steroidal anti-inflammatory drugs, and biologicals. Influencing factors like the selection of stimulants or of the identification and activation markers, the stimulation protocol, gating strategies, and cutoff definition are addressed in this overview on BAT performance. The overall aim is to evaluate the suitability of BAT as biomarker for the diagnosis of immediate drug-induced hypersensitivity reactions.

Basophil Activation in Immediate Drug Hypersensitivity Reactions and Basophil Activation Test (BAT)

“…Sometimes, they are used together in the evaluations. It is known that the sensitivity and specificity of BAT increase when they are used together (9)(10)(11)(12)(13)(14).…”

“…Molecular expressions such as eotaxin CC chemokine receptor 3 (CCR3), IL-3 receptor α-chain (CD123), prostaglandin D2 receptor (CRTH-2), and basophil-specific ectonuclease CD203c are also used in the identification strategies (10). In cytometry, the expressions of CD63 and CD203c is examined as the activation markers of basophils.…”

“…Again, the severity of activation is measured through the stimulation index (SI) (%). The basophil cells that turn to CD63 /CD203C positivity with allergen compared to the negative control are measured by SI (%) or the MFI signal of the activation markers (10,15). Again, the measurement that is called the area under the dose curve (AUC) depends on the combined assessment of basophil reactivity (maximal activation) and sensitivity (half of maximal activation).…”

“…Other factors affecting the test include the selection of the stimulus, the stimulation protocol, the activation markers that are examined, the gating strategy, and the identification of the cutoff ratio (10,15).…”

“…The test tubes are then rotated at 4°C and 200´g for 5 min. After the tubes are prepared, in order to select the basophil and measure the activity before starting to work in flow cytometry, the cells are stained with 20 μL monoclonal anti-human IgE, 10 μL monoclonal CD63, and 10 μL CD203C antibodies on ice for 20 min (9)(10)(11)(12)(13)(14). Then, the tubes are worked on in the flow cytometry.…”