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Alexandra F. Santos - One of the best experts on this subject based on the ideXlab platform.
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Basophil Activation test: Mechanisms and considerations for use in clinical trials and clinical practice.
Allergy, 2021Co-Authors: Alexandra F. Santos, Oral Alpan, Hans Jurgen HoffmannAbstract:The Basophil Activation test (BAT) is a functional assay that measures the degree of degranulation following stimulation with allergen or controls by flow cytometry. It correlates directly with histamine release. From the dose-response curve resulting from BAT in allergic patients, Basophil reactivity (%CD63+ Basophils) and Basophil sensitivity (EC50 or similar) are the main outcomes of the test. BAT takes into account all characteristics of IgE and allergen and thus can be more specific than sensitization tests in the diagnosis of allergic disease. BAT reduces the need for in vivo procedures, such as intradermal tests and allergen challenges, which can cause allergic reactions of unpredictable severity. As it closely reflects the patients' phenotype in most cases, it may be used to support the diagnosis of food, venom and drug allergies and chronic urticaria, to monitor the natural resolution of food allergies and to predict and monitor clinical the response to immunomodulatory treatments, such as allergen-specific immunotherapy and biologicals. Clinical application of BAT requires analytical validation, clinical validation, standardization of procedures and quality assurance to ensure reproducibility and reliability of results. Currently, efforts are ongoing to establish a platform that could be used by laboratories in Europe and in the USA for quality assurance and certification.
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Basophil Activation Test Reduces Oral Food Challenges to Nuts and Sesame
The journal of allergy and clinical immunology. In practice, 2020Co-Authors: Alexandra F. Santos, Gideon Lack, Matthew Kwok, Marcel Bergmann, Helen A. Brough, Natália Couto-francisco, Valentina Panetta, Diab Haddad, Philippe Eigenmann, Jean-christoph Roger J-p CaubetAbstract:Background Nut allergic patients are often IgE sensitized to other nuts/seeds and need multiple oral food challenges (OFCs) before the safe nuts can be introduced in the diet. However, OFCs are time-consuming and risky procedures. Objective To assess the utility of the Basophil Activation test (BAT) to predict the allergic status and reduce the need for an OFC in children with 1 or more nut or seed allergies. Methods Participants in the Pronuts study recruited at the Geneva and the London centers were tested on the BAT to hazelnut, cashew nut, sesame, almond, and peanut, Ara h 1, Ara h 2, Ara h 6, using FlowCAST, a commercially available BAT kit, and flow cytometry. Results The BAT to hazelnut, cashew nut, sesame, almond, and peanut discriminated between allergic and nonallergic children, to the respective nut or seed. The optimal allergen concentration and their optimal, positive, and negative cutoffs were identified for the BAT and the other tests, for each nut and seed. Using the BAT as a second step in the diagnostic process, after equivocal skin prick test and IgE to extracts and components, reduced the number of total OFCs by 5% to 15% and positive OFCs by 33% to 75% (except for hazelnut) with 0% false-negatives and a diagnostic accuracy of 96% to 100%. Conclusion The BAT proved to be a useful diagnostic tool, used in a stepwise approach, to predict the allergic status and reduce the number of OFCs in the Pronuts study participants with at least 1 nut allergy willing to consume selected nuts.
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Basophil Activation test mechanisms and considerations for use in clinical trials and clinical practice
Authorea Preprints, 2020Co-Authors: Alexandra F. Santos, Oral Alpan, Hans Jurgen HoffmannAbstract:The Basophil Activation test (BAT) is a functional assay that measures the degree of degranulation following stimulation with allergen or controls by flow cytometry and is directly correlated with histamine release. From the bell-shaped curve resulting from BAT in allergic patients, Basophil reactivity (given by %CD63+ Basophils) and Basophil sensitivity (given by EC50 or similar) are the main outcomes of the test. BAT takes into account all characteristics of IgE and allergen and thus can be more specific than sensitization tests in the diagnosis of allergic disease. BAT reduces the need for in vivo procedures, such as intradermal tests and allergen challenges, which can cause allergic reactions of unpredictable severity. As it closely reflects the patients’ phenotype, it can potentially be used to monitor the natural resolution of food allergies and to predict and monitor clinical response to immunomodulatory treatments, such as allergen-specific immunotherapy and biologicals. Clinical application of BAT requires analytical validation, clinical validation, standardization of procedures and quality assurance to ensure reproducibility and reliability of results. Currently, efforts are ongoing to establish a platform that could be used by laboratories in Europe and in the USA for certification.
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Basophil Activation Test: Old and New Applications in Allergy.
Current allergy and asthma reports, 2018Co-Authors: Oliver Hemmings, Matthew Kwok, Richard Thomas Mckendry, Alexandra F. SantosAbstract:Purpose of Review The Basophil Activation test (BAT) using flow cytometry has supplanted traditional methods of measuring Basophil degranulation using histamine and other mediator release, and can be used for clinical applications as well as to explore the immune mechanisms of effector cell response to allergen. This review discusses the advancements made in clinical, diagnostic and laboratory research of allergy utilizing an ever-evolving BAT.
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Basophil Activation test old and new applications in allergy
Current Allergy and Asthma Reports, 2018Co-Authors: Oliver Hemmings, Matthew Kwok, Richard Thomas Mckendry, Alexandra F. SantosAbstract:The Basophil Activation test (BAT) using flow cytometry has supplanted traditional methods of measuring Basophil degranulation using histamine and other mediator release, and can be used for clinical applications as well as to explore the immune mechanisms of effector cell response to allergen. This review discusses the advancements made in clinical, diagnostic and laboratory research of allergy utilizing an ever-evolving BAT. Being an in vitro surrogate of the allergic reaction that happens in vivo in the sick patient, the BAT can be used to support the diagnosis of various allergic conditions, such as food, drug, respiratory and insect venom allergies, and the assessment of clinical response to allergen-specific immunotherapy and other immunomodulatory treatments. The BAT can also be used for research purposes to explore the mechanisms of allergy and tolerance at the level of the Basophil, for instance by manipulating IgE and IgG and their receptors and by studying intracellular signalling cascade in response to allergen. This review covers the applications of the BAT to the clinical management of allergic patients and the increased understanding of the mechanisms of immune response to allergens as well as technological advancements made in recent years.
J. Ring - One of the best experts on this subject based on the ideXlab platform.
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A new Basophil Activation test using CD63 and CCR3 in allergy to antibiotics
Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology, 2010Co-Authors: Bernadette Eberlein, H Behrendt, Ulf Darsow, I. León Suárez, Franziska Ruëff, J. RingAbstract:Summary Background Flow cytometric Basophil Activation tests (BAT) have been developed as cellular tests for in vitro diagnosis of IgE-mediated reactions. Different markers and techniques have been used after stimulation with various allergens. Objective It was the aim of the present study to compare an established BAT (Flow-CAST®) with a newly developed Basophil Activation protocol using CD63 and CCR3 (Flow2 CAST®) in patients with type-I allergy to antibiotics. Materials and methods Twenty-four patients with a history of type-I allergy to antibiotics were examined. A careful allergy history was taken, and skin tests and determination of specific IgE antibodies were performed. Two different BAT using CD63 expression but different protocols were carried out after stimulation with different concentrations of antibiotics. Fifteen healthy subjects without a history of antibiotic allergy were studied as controls. Results The Flow2 CAST® showed a higher sensitivity than the Flow-CAST® (55% vs. 53%) with regard to patients' history. Specificity was 80% both for the Flow2 CAST® and for the Flow-CAST® with regard to controls with negative history and negative RAST. Conclusion These results show the value of two different BAT as cellular tests in the in vitro diagnosis of patients with antibiotic allergy with equal specificity and a slightly higher sensitivity for the Flow2 CAST®. Cite this as: B. Eberlein, I. Leon Suarez, U. Darsow, F. Rueff, H. Behrendt and J. Ring, Clinical & Experimental Allergy, 2010 (40) 411–418.
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comparison of Basophil Activation tests using cd63 or cd203c expression in patients with insect venom allergy
Allergy, 2006Co-Authors: B Eberleinkonig, H Behrendt, Ulf Darsow, R Varga, Martin Mempel, J. RingAbstract:BACKGROUND: Flow cytometric Basophil Activation tests have been developed as cellular tests for in vitro diagnosis of IgE-mediated reactions. Different Activation markers (CD63 or CD203c) with distinct ways of regulation have been used after stimulation with various allergens. OBJECTIVE: It was the aim of the present study to compare Basophil Activation tests by measuring both CD63 and CD203c upregulation in patients with insect venom allergy. MATERIALS AND METHODS: 43 patients with a history of insect venom anaphylaxis were examined. A careful allergy history was taken, and skin tests and determination of specific IgE-antibodies were performed. Basophil Activation tests (BAT) using CD63 or CD203c expression were done after stimulation with different concentrations of bee and wasp venom extracts. 25 healthy subjects with negative history of insect venom allergy were studied as controls. RESULTS: The CD203c protocol showed a slightly higher sensitivity than the CD63 protocol (97% vs. 89%) with regard to patients' history. The magnitude of Basophil response was higher with CD203c in comparison to CD63 for both insect venoms. Specificity was 100% for the CD63 protocol and 89% for the CD203c protocol with regard to controls with negative history and negative RAST. CONCLUSION: These results support the reliability of Basophil Activation tests using either CD63 or CD203c as cellular tests in the in vitro diagnosis of patients with bee or wasp venom allergy with a slightly higher sensitivity for the CD203c protocol.
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in vitro Basophil Activation using cd63 expression in patients with bee and wasp venom allergy
Journal of Investigational Allergology and Clinical Immunology, 2006Co-Authors: B Eberleinkonig, C Schmidtleidescher, H Behrendt, Jurgen Rakoski, J. RingAbstract:Summary. The diagnosis of insect venom allergy and the indication for specific immunotherapy is based on history, skin tests and demonstration of hymenoptera venom-specific IgE-antibodies. Cellular tests can add useful information but the role of Basophil Activation tests for the different venoms has to be elucidated further. We evaluated positive reactions in a Basophil Activation test using CD63 expression as marker independently for bee or wasp venom in patients with hymenoptera allergy. Fifty-seven patients with a history of insect venom anaphylaxis were examined (12 x bee venom, 39 x wasp venom, 6 x bee plus wasp venom). Skin tests and determination of specific IgE-antibodies were performed. Basophil Activation test (BAT) using CD63 expression was performed after stimulation with different concentrations of bee and wasp venom. The BAT is based on double staining with anti-IgE antibodies and anti-CD63 and subsequent determination of the percentage of activated Basophils by flow cytometry. In patients with bee venom allergy, BAT was positive in 100% to bee venom and 75% to wasp venom. In patients with bee and wasp venom allergy, positive reactions for both venoms were found in 100%. In patients with wasp venom allergy, 97% reacted positive to wasp venom and only 56% to bee venom. These results show the reliability of the Basophil Activation test as a cellular test in the in vitro diagnosis in patients with bee and wasp venom allergy. They also show that positive reactions in the Basophil Activation test reflect both sensitization status and cross-reactivity between venom species.
Werner Aberer - One of the best experts on this subject based on the ideXlab platform.
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cd203c based Basophil Activation test in allergy diagnosis characteristics and differences to cd63 upregulation
Cytometry Part B-clinical Cytometry, 2010Co-Authors: Eva M. Sturm, Akos Heinemann, Werner Aberer, Bettina Kranzelbinder, Andrea Groseljstrele, Gunter J. SturmAbstract:Background: The Basophil Activation test (BAT) based on CD203c upregulation has been validated as a reliable tool for the diagnosis of IgE-mediated allergies. Nevertheless, CD203c-based BAT is hardly comparable with that of CD63-based tests, as the mechanisms of CD203c versus CD63 induction differ considerably. The aim of the present study was to identify potent influencing factors of the CD203cbased BAT and to emphasize differences between CD63 and CD203c detection. Methods: CD203c-based BAT was determined in 82 healthy controls and in 79 allergic patients. The effects of interleukin (IL)-3 and degranulation enhancing substances were investigated and compared with CD63 upregulation. Furthermore, the influence of different storage conditions and incubation times was evaluated and the impact of antiallergic drugs on the test results was assessed. Results: CD203c and CD63 expression was rapidly upregulated reaching a maximum after 20–30 min. Basophil CD203c upregulation assayed after storage times up to 48 h declined already after 4 h. IL-3 treatment increased CD203c and CD63 baseline levels and decreased Basophil CD203c responses in a dose-dependent manner. In contrast, cytochalasin B and latrunculin B did not affect CD203c responses but decreased CD63-based BAT. Finally, therapeutic concentrations of dimetindene and desloratadine did not affect CD203c upregulation. Conclusion: CD203c-based Basophil Activation test should be performed preferentially within 4 h after taking the blood samples. Priming and degranulation-enhancing factors are not required for CD203cbased BAT. In contrast to skin testing, CD203c-based BAT can be performed in patients undergoing antiallergic treatment. V C 2010 International Clinical Cytometry Society
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The Basophil Activation test in the diagnosis of allergy: technical issues and critical factors.
Allergy, 2009Co-Authors: Gunter J. Sturm, Akos Heinemann, Eva M. Sturm, Bettina Kranzelbinder, Andrea Groselj-strele, Werner AbererAbstract:Background: The Basophil Activation test (BAT) is a widely validated and reliable tool especially for the diagnosis of hymenoptera venom allergy. Nevertheless, several pitfalls have to be considered and outcomes may differ because of diverse in-house protocols and commercially available kits. We aimed to identify the factors that may influence results of the CD63-based BAT. Methods: Basophil responses to monoclonal anti-IgE (clone E124.2.8) and bee and wasp venom were determined by BAT based on CD63. The effect of stimulating factors such as, IL-3, cytochalasin B and prewarming of the samples was investigated. Furthermore, we compared two different flow cytometer systems and evaluated the influence of storage time, different staining protocols and anti-allergic drugs on the test results. Results: Interleukin-3 enhanced the reactivity of Basophils at 300 pM, but not at 75 and 150 pM. Prewarming of samples and reagents did not affect Basophil reactivity. CD63 expression assayed after storage time of up to 48 h showed that Basophil reactivity already started to decline after 4 h. Basophils stained with HLA-DR-PC5 and CD123-PE antibodies gated as HLA-DRneg/CD123pos cells showed the highest reactivity. No effect on test outcomes was observed at therapeutic doses of dimetindene and desloratadine. Finally, slight differences in the percentage of activated Basophils, depending on the cytometer system used, were found. Conclusion: Basophil Activation test should be performed as early as possible after taking the blood sample, preferably within 4 h. In contrast to the skin test, BAT can be performed in patients undergoing treatment with antihistamines. For reasons of multiple influencing factors, BAT should be performed only at validated laboratories.
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The CD63 Basophil Activation test in Hymenoptera venom allergy: a prospective study
Allergy, 2004Co-Authors: Gunter J. Sturm, E. Böhm, M. Trummer, I. Weiglhofer, Akos Heinemann, Werner AbererAbstract:Background: The Basophil Activation test (BAT), which relies on flow cytometric quantitation of the allergen-induced up-regulation of the granule-associated marker CD63 in peripheral blood Basophils, has been suggested to be a useful approach in detecting responsiveness to allergens. The purpose of this study was to establish the usefulness of the BAT with regard to the clinical history and current diagnostic tools in Hymenoptera venom allergy using a prospective study design. Methods: Fifty-seven consecutive patients allergic to Hymenoptera venom as defined by a systemic reaction after an insect sting, and 30 age- and sex-matched control subjects with a negative history were included. The degree and nature of sensitization was confirmed by skin testing, specific immunoglobulin E (IgE), serum tryptase levels and BAT. In the nonallergic control group only analysis of specific IgE and BAT were performed. Correlation of BAT, skin test and specific IgE, respectively, with the clinical history in the allergic group was termed as sensitivity and in the control group as specificity. Results: Twenty one of 23 (91.3%) bee venom allergic patients and 29 of 34 (85.3%) patients allergic to wasp and hornet venom tested positive in BAT. The overall sensitivity of BAT, specific IgE and skin tests were 87.7, 91.2 and 93.0%, respectively. The overall specificities were 86.7% for BAT and 66.7% for specific IgE. No correlation between the severity of clinical symptoms and the magnitude of Basophil Activation was observed. Conclusion: The BAT seems to be an appropriate method to identify patients allergic to bee or wasp venom with a comparable sensitivity to standard diagnostic regimens. The higher specificity of BAT as compared with specific IgE makes this test a useful tool in the diagnosis of Hymenoptera venom allergy.
B Eberleinkonig - One of the best experts on this subject based on the ideXlab platform.
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comparison of Basophil Activation tests using cd63 or cd203c expression in patients with insect venom allergy
Allergy, 2006Co-Authors: B Eberleinkonig, H Behrendt, Ulf Darsow, R Varga, Martin Mempel, J. RingAbstract:BACKGROUND: Flow cytometric Basophil Activation tests have been developed as cellular tests for in vitro diagnosis of IgE-mediated reactions. Different Activation markers (CD63 or CD203c) with distinct ways of regulation have been used after stimulation with various allergens. OBJECTIVE: It was the aim of the present study to compare Basophil Activation tests by measuring both CD63 and CD203c upregulation in patients with insect venom allergy. MATERIALS AND METHODS: 43 patients with a history of insect venom anaphylaxis were examined. A careful allergy history was taken, and skin tests and determination of specific IgE-antibodies were performed. Basophil Activation tests (BAT) using CD63 or CD203c expression were done after stimulation with different concentrations of bee and wasp venom extracts. 25 healthy subjects with negative history of insect venom allergy were studied as controls. RESULTS: The CD203c protocol showed a slightly higher sensitivity than the CD63 protocol (97% vs. 89%) with regard to patients' history. The magnitude of Basophil response was higher with CD203c in comparison to CD63 for both insect venoms. Specificity was 100% for the CD63 protocol and 89% for the CD203c protocol with regard to controls with negative history and negative RAST. CONCLUSION: These results support the reliability of Basophil Activation tests using either CD63 or CD203c as cellular tests in the in vitro diagnosis of patients with bee or wasp venom allergy with a slightly higher sensitivity for the CD203c protocol.
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in vitro Basophil Activation using cd63 expression in patients with bee and wasp venom allergy
Journal of Investigational Allergology and Clinical Immunology, 2006Co-Authors: B Eberleinkonig, C Schmidtleidescher, H Behrendt, Jurgen Rakoski, J. RingAbstract:Summary. The diagnosis of insect venom allergy and the indication for specific immunotherapy is based on history, skin tests and demonstration of hymenoptera venom-specific IgE-antibodies. Cellular tests can add useful information but the role of Basophil Activation tests for the different venoms has to be elucidated further. We evaluated positive reactions in a Basophil Activation test using CD63 expression as marker independently for bee or wasp venom in patients with hymenoptera allergy. Fifty-seven patients with a history of insect venom anaphylaxis were examined (12 x bee venom, 39 x wasp venom, 6 x bee plus wasp venom). Skin tests and determination of specific IgE-antibodies were performed. Basophil Activation test (BAT) using CD63 expression was performed after stimulation with different concentrations of bee and wasp venom. The BAT is based on double staining with anti-IgE antibodies and anti-CD63 and subsequent determination of the percentage of activated Basophils by flow cytometry. In patients with bee venom allergy, BAT was positive in 100% to bee venom and 75% to wasp venom. In patients with bee and wasp venom allergy, positive reactions for both venoms were found in 100%. In patients with wasp venom allergy, 97% reacted positive to wasp venom and only 56% to bee venom. These results show the reliability of the Basophil Activation test as a cellular test in the in vitro diagnosis in patients with bee and wasp venom allergy. They also show that positive reactions in the Basophil Activation test reflect both sensitization status and cross-reactivity between venom species.
A.l. De Weck - One of the best experts on this subject based on the ideXlab platform.
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a new combined test with flowcytometric Basophil Activation and determination of sulfidoleukotrienes is useful for in vitro diagnosis of hypersensitivity to aspirin and other nonsteroidal anti inflammatory drugs
International Archives of Allergy and Immunology, 2005Co-Authors: M L Sanz, P M Gamboa, A.l. De WeckAbstract:Background: We assessed whether nonsteroidal anti-inflammatory drugs (NSAIDs) may provoke blood Basophil Activation in vitro in aspirin- and NSAID-hypersensitive patients, as detect
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Flow cytometric Basophil Activation test: a review.
Journal of investigational allergology & clinical immunology, 2002Co-Authors: Maria L. Sanz, J.p. Maselli, Pedro M. Gamboa, A. Oehling, I. Diéguez, A.l. De WeckAbstract:Flow cytometry is a technique enabling the analysis of physical and biological characteristics of cells or other biological particles when labeled with antibodies coupled to fluorochromes or other dyes. The Basophil Activation test (BAT), also called flow-cytometric allergen stimulation test (FAST) [commercially available under the name of Flow CAST (Buhlmann Laboratories) or BASOTEST (Beckton-Dickinson)] is based on the in vitro allergen-induced specific Activation of Basophils. This assay rests on the demonstration of some membrane protein markers that appear after exposure to the allergen. This paper reviews some of the literature about the use of this technique in the investigation of immediate-type allergies to inhalant allergens, drugs, and foods, as well as our own experience with this diagnostic technique. Flow cytometry is a reliable method for the quantification of Basophil Activation after allergenic stimulus in vitro and in vivo. It also enables us to detect allergic and pseudoallergic reactions because of other mechanisms than allergen-specific IgE antibodies. Further clinical evaluation of this technique will allow validation and better establishment of its diagnostic value in allergy.
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allergen induced Basophil Activation cd63 cell expression detected by flow cytometry in patients allergic to dermatophagoides pteronyssinus and lolium perenne
Clinical & Experimental Allergy, 2001Co-Authors: M L Sanz, P M Gamboa, I. Diéguez, G Sanchez, L Vila, C Uasuf, M Chazot, A.l. De WeckAbstract:Background In this study, we determined by flow cytometry the percentage of Basophils activated after in vitro stimulation by allergens and expressing the CD63 marker. The diagnostic reliability of the technique was assessed as well as its correlation with other in vitro diagnostic parameters. Methods Fifty-three patients suffering from asthma and/or allergic rhinitis following sensitization to Dermatophagoides pteronyssinus and 51 patients sensitized to Lolium perenne were investigated. Twenty-four atopic patients not sensitive to these allergens and 38 healthy subjects were also selected as controls. The Basophil Activation test determines the percentage of Basophils which express CD63 as an Activation marker, by means of flow cytometry, after in vitro stimulation with allergen, using double labelling with monoclonal antibody anti-CD63-PE and anti-IgE-FITC. Results No differences in basal values (non-activated control) were found between sensitized patients, atopic controls and healthy controls. On the other hand, sensitized patients showed a significantly higher percentage of activated Basophils after stimulation by allergens in vitro than both control groups (P < 0.001). We found a significant correlation between skin tests and Basophil Activation tests (r = 0.72, P < 0.001). We also found a positive and significant correlation between Basophil Activation tests and histamine release tests (r = 0.80, P < 0.001), allergen-specific sulphidoleukotriene production (r = 0.7, P < 0.001) and the occurrence of serum allergen-specific IgE (r = 0.71, P < 0.001). Conclusion The Basophil Activation test is a highly reliable technique in the diagnosis of allergy to inhalant allergens. The sensitivity of the Basophil Activation test was 93.3%, and its specificity 98.4%, when using a cut-off point of 15% activated Basophils as positive result.