Basophil activation test for the in vitro diagnosis of nonsteroidal anti-inflammatory drug hypersensitivity

There is need for an in vitro diagnostic test for hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs). The purpose of this study was to assess the reliability of one such diagnostic, the basophil activation test. Forty-three drug hypersensitive patients referring several immediate reactions (anaphylaxis, urticaria, angioedema, asthma, and rhinoconjunctivitis) to one or more NSAIDs and 29 controls participated. Using the Basotest commercial kit, 63 determinations were performed with the drugs implicated in the adverse reactions (ASA, ibuprofen, metamizol, diclofenac, paracetamol, and ketorolac). In 16 patients additional determinations were made with other chemically unrelated NSAIDs. Forty-two determinations were made for controls. The analysis was performed by flow colorimetric cytometry and double staining with the monoclonal antibodies anti-IgE and anti-CD63. A Basophil Activation Index (percentage of activated basophils after allergen stimulation/percentage of basally activated basophils) of two or more was considered a positive result. Specificity of 100% and sensitivity of 42.85% were achieved. The positive predictive value was 100%, and the negative predictive value was 53.84%. In 35.29% of intolerant patients there was a positive reaction to at least two drugs implicated in adverse reactions, and in 27.27% of these patients there was a positive reaction to other chemically unrelated NSAIDs. The basophil activation test is useful for the in vitro diagnosis of NSAID hypersensitivity, providing good specificity and positive predictive value and diagnostic reliability in the assessment of NSAID intolerance.