SUGGESTIONS FOR DIAGNOSING HYPER-REACTIVITY TO LOCAL ANESTHETICS BASED ON A FLOW CYTOMETRIC STUDY

Identification of the antigens responsible for allergic reac- tions is essential both for diagnostic purposes and for an effec- tive prevention. Allergic reactions towards local anesthetics may also be caused by the stabilizing agents used in prepara- tions with adrenaline as vasoconstrictor. Aim of our work was to demonstrate that a complete diagnosis of hypersensitivity to such drugs should also include the analysis of the minor vial ingredients. Subjects referring allergic reactions to local anaes- thetics were enrolled and their blood samples assayed for both the active principle and the additives (K-metabisulphite).Basophil Activation Tests used for revealing subjects’ reactivity have been validated for in vitro diagnostics (CE- IVD). They are based on the flow cytometry detection of CD63 and CD203c markers following cells incubation with the selected allergen. Degranulation triggers CD63 expres- sion on cellular surface, release of preformed mediators (histamine etc.) as well, while CD203c becomes over- expressed in response to allergens.The study was performed within IRMA laboratories on 63 patients referring a previous anaphylaxis history towards local anaesthetics with adrenaline. From the group testing lidocaine, 14 subjects on 32 were sensitive to the E224, 9 of which did not react to the active principle itself as expected. 22 individuals tested mepivacaine: 12 were positive to E224, 6 of them did not show reactivity towards mepivacaine. On 9 testing articaine, 2 patients were positive to E224 only.BATs revealed a good level of reliability in the detec- tion of drug hyper-reactivity (62.5% for lidocaine sensitivity, 72.27% for mepivacaine, 55.5% for articaine), being thus suggested for the baseline diagnosis of suspected sensitiza- tion. Our results also pointed out the need for widening the analysis towards additives of food and drugs.