In vitro diagnosis of IgE-mediated allergy: breakthroughs in the last decade

Abstract

Background This article briefly reviews the historical development, present status and perspectives of the diagnosis of IgE-mediated allergy. After more than a century of relying on skin testing and 40 years of relying on quantification of specific IgE antibodies for the diagnosis of IgE-mediated allergy, clinicians now have access to different novel in vitro diagnostics in the form of component-based assays and flow-assisted quantification of activated basophils. Although these techniques already constitute key advances in the diagnosis of allergy, it is anticipated that future developments, such as epitope mapping and identification of novel basophil activation markers, might further improve management of the allergic patient. In this context, the recent development of a flow cytometric technique to analyze histamine release at a single cell level might represent a significant step forward. IgE-mediated allergies constitute an important and increasing health problem with significant morbidity and potential mortality. Correct diagnosis with identification of all offending allergens is an absolute prerequisite for appropriate and potentially life-saving preventive measures or the initiation of allergen-specific immunotherapy. The diagnostic algorithm for IgE-mediated allergy involves a thorough clinical history that is documented by the demonstration of allergen-specific IgE (specific IgE) antibody by either in vivo skin testing (prick/intradermal) or a serologic assay. Although these tests can provide useful information, they do not demonstrate an absolute predictive value and the results are not always unequivocal. In these cases, where there exists a discrepancy between history and results from quantification of sIgE and/or skin tests, additional tests such as mediator release assays or (double-blind placebo-controlled) challenge tests have long been used to establish correct diagnosis. During the last decade two novel in vitro assays have entered the allergy diagnostics arsenal, that is, component-resolved allergy diagnosis (CRD) and the basophil activation test by flow cytometry.