Basophil activation test in allergy: time for an update?

A wide range of reported evidence in the literature has shown that the quantification of basophil activation by flow cytometry (basophil activation test, BAT) has proven to be a useful tool for the assessment of immediate-type responses to allergens mediated by IgE or other mechanisms in allergic patients. The usefulness of BAT in anaphylactic adverse reactions, late-onset allergy and immunotherapy follow-up has also been demonstrated. To date, most BAT studies reported in the literature involved the capture of basophils only with a fluorochrome-labeled anti-IgE antibody and application of CD63 upregulation in order to evaluate the basophil response to allergens. Many issues need to be addressed, such as optimizing the analytical performance of the test, checking preanalytical conditions, the selection of the flow cytometry best gating protocol, the introduction of new algorithms and parameters, the search for new activation markers and the introduction of anti-IgE controls. BAT is certainly a useful technique, also for isolated cases of hypersensitivity to various other compounds and drugs, and an update of its application is certainly an interesting topic to expand the debate on allergy diagnosis.