Flow-Cytometric Cellular Allergen Stimulation Test in Latex Allergy

Abstract

Background: The use of flow-cytometric basophil activation to different allergens has been recommended in recent years. In this study, we analyzed the diagnostic reliability of the flow-cytometric allergen stimulation test (FAST) after latex-specific stimulation in vitro. The diagnostic reliability of the technique was assessed as well as its correlation with other in vitro diagnostic parameters. Methods: 43 patients allergic to latex with a positive history and skin test participated in the study. Thirty subjects (20 of them exposed to latex) with a negative history, skin tests and serum-specific IgE determination to latex were used as controls. In FAST the percentage of basophils that express CD63 as an activation marker after in vitro stimulation with allergen (latex) is determined by flow cytometry, following double labelling with the monoclonal antibodies anti-CD63-PE and anti-IgE FITC. Results: Intraclass correlation coefficient in FAST with latex was 0.995 (p < 0.0001), which demonstrates the excellent reproducibility of this technique. Taking a cutoff point of 10% by means of ROC curves, FAST yields a sensitivity of 93% and a specificity of 100%. The FAST positive predictive value in latex allergy was 100% and the negative predictive value was 99.9%. We found a positive and significant correlation between FAST and specific IgE (CAP) with the histamine release test and specific sulphidoleukotriene production [cellular allergen stimulation test (CAST); p < 0.05]. Conclusions: FAST is a highly reliable technique (93% sensitivity and 100% specificity) in the in vitro diagnosis of IgE-mediated latex allergy.

Hypoallergenic Variants of the Major Latex Allergen Hev b 6.01 Retaining Human T Lymphocyte Reactivity

“…As an alternative to SPT, with its inherent safety risks, the BAT was used in this study to measure the relative ability of the WT Ags, rHev b 6.01 mutants, and Hev b 6.02 peptide variants to activate basophils. Although BAT is recognized as a very sensitive and specific assay for the diagnosis of latex allergy (43), there have been no direct comparisons of BAT and skin prick testing with recombinant latex proteins. Although it has been reported that 1 to 10 ng/ml recombinant latex allergen will elicit a positive SPT response (38), we found a lack of activation of basophils with 10 g/ml rHev b 6.01 mutants.…”

Anaphylaxis during anaesthesia: diagnostic approach

“…In most patients, diagnosis of NRL anaphylaxis can readily be established by quantification of sIgE (k82), skin tests, or both (77)(78)(79). Although these tests are highly reliable, results of are not always unequivocal (80), and some patients might need additional tests such as basophil activation (81)(82)(83) or challenge tests (84,85) to establish diagnosis.…”

Confirmation of the Diagnosis of Natural Rubber Latex Allergy by the Basotest^® Method

“…Moreover, as we have previously described [7]neither the results of the Basotest nor the IgE level were correlated with the patient’s sensitivity assessed by skin prick test (results not shown) and clinical history. Several studies [13, 14, 15]have evaluated the interest of flow cytometry basophil stimulation tests in the same setting (table 2). Similar specificity values were reported [15].…”

“…In the literature, studies utilized different thresholds of positivity: Sanz et al [13]calculated the threshold value at 10% using ROC curves, Boumiza et al [14]determined the positivity by 2 sequential latex dilutions inducing an increase of more than 10% above control levels and Ebo et al [15]estimated the threshold at 17% using ROC curves as well.…”