Indoor, long-term persistence of cypress pollen allergenic potency: a 10-month study

This study was previously presented as a poster at the 6th Congres Francophone d’Allergologie; April 19-22, 2011; Paris, France.International audienc

Streamlining basophil activation testing to enable assay miniaturization and automation of sample preparation

Background: Numerous studies have demonstrated the capabilities of the basophil activation test (BAT) but various parameters such as a lack of standardization and a time consuming and labor intensive workflow continue to hinder the field to fully leverage the capabilities of this technique. When pediatric patients have to be considered, an additional limitation is related to blood volume consumption. Objectives: This work aimed at developing and characterizing a simplified and standardized whole-blood based BAT prototype procedure and at further assessing the feasibility of automating and miniaturizing the developed assay into a 96 well plate format. Methods: A dry and room temperature stable reagent technology was used to simplify and standardize BAT. Under optimized conditions, EDTA anticoagulated whole blood samples of non-allergic and allergic donors ( < 24 h old) together with calcium containing buffer were added to ready-to-use dry reagent tubes or 96 well plates (negative controls, positive controls and allergen tests) containing a 5 color compensation-free antibody panel (CD45-KrO/CD3-PC7/CRTH2-A647/CD203c-PE/CD63-PB). Upon mixing and incubation at 37 degrees C for 15 min, erythrocytes were lysed and samples were analyzed by flow cytometry without further washing steps. While it is important to precisely control the incubation time to minimize the assay variability, herein, a 15 min incubation time was chosen as it provides a suitable compromise for both the magnitude of basophil activation and the quality of the staining. A Biomek NXP robotic platform (Beckman Coulter) was used for automation and both CD203c and CD63 levels were monitored to characterize basophil reactivity. Results: This streamlined BAT protocol is no-wash, compensation free and only requires 4 pipetting steps to be completed. The assessment of assay performance characteristics showed wide applicability, satisfactory repeatability and a high degree of standardization as demonstrated by very low infra-assay and inter-operator variabilities (CVs < 10%). Leveraging these technical foundations, it was then proven that this new BAT procedure can easily be transposed into the 96 well plate format, thereby benefiting from a miniaturized format and full automation capabilities. When considering 8 dilution points to characterize the ex vivo basophil reactivity of a given whole blood sample, we found that as little as 51.1.L of blood per point could be used. Conclusions: A whole blood based and simplified procedure for BAT is proposed. It relies on a dry antibody formulation technology and requires only a few manual steps to be completed. This procedure can also be transposed in a 96 well plate format, fully automated and miniaturized, when sample volume reduction, throughput increase or unattended sample preparation is required

Two Different Composite Markers Predict Severity and Threshold Dose in Peanut Allergy

International audienceWhat is already known about this topic? Peanut allergy is one of the most frequent causes of anaphylaxis in children with food allergies. Oral food challenge remains the gold standard to evaluate the threshold dose and severity of peanut allergy. What does this article add to our knowledge? This study reports the relevance of allergen-specific and noneallergen-specific basophil activation test parameters to determine the severity and threshold dose of a peanut-allergic reaction in children. How does this study impact current management guidelines? Introduction of these multivariable models in routine practice could avoid an oral food challenge in some children with peanut allergy. BACKGROUND: Safe and cost-effective biological surrogate markers to evaluate the severity and threshold dose of peanut allergy (PA) reactions during an oral food challenge (OFC) are lacking. OBJECTIVE: To evaluate biological markers associated with the severity and threshold dose of an allergic reaction during an OFC in a population of children with PA. METHODS: Demographic and biological parameters of children with peanut OFC and basophil activation test (BAT) results were collected. Patients were stratified into 2 severity groups (mild-to-moderate and severe) and 2 cumulative threshold dose groups: low (LCTG) £100 mg crushed peanut and high >100 mg. RESULTS: Among the 68 children included, there was a 96% concordance between the OFC and BAT result for the diagnosis of PA. Of the 56 children with a positive OFC and BAT to peanut (median age: 8.8 years), the severity of an allergic reaction and the cumulative threshold dose were not correlated (P [ .24). Higher Ara h 2especific IgE and FcεRI-positive control values were both associated with severe reactions to peanut. Combining these 2 markers led to a 92% sensitivity (84%-97%) and an 82% specificity (71%-89%) for sever

Two Different Composite Markers Predict Severity and Threshold Dose in Peanut Allergy

International audienceWhat is already known about this topic? Peanut allergy is one of the most frequent causes of anaphylaxis in children with food allergies. Oral food challenge remains the gold standard to evaluate the threshold dose and severity of peanut allergy. What does this article add to our knowledge? This study reports the relevance of allergen-specific and noneallergen-specific basophil activation test parameters to determine the severity and threshold dose of a peanut-allergic reaction in children. How does this study impact current management guidelines? Introduction of these multivariable models in routine practice could avoid an oral food challenge in some children with peanut allergy. BACKGROUND: Safe and cost-effective biological surrogate markers to evaluate the severity and threshold dose of peanut allergy (PA) reactions during an oral food challenge (OFC) are lacking. OBJECTIVE: To evaluate biological markers associated with the severity and threshold dose of an allergic reaction during an OFC in a population of children with PA. METHODS: Demographic and biological parameters of children with peanut OFC and basophil activation test (BAT) results were collected. Patients were stratified into 2 severity groups (mild-to-moderate and severe) and 2 cumulative threshold dose groups: low (LCTG) £100 mg crushed peanut and high >100 mg. RESULTS: Among the 68 children included, there was a 96% concordance between the OFC and BAT result for the diagnosis of PA. Of the 56 children with a positive OFC and BAT to peanut (median age: 8.8 years), the severity of an allergic reaction and the cumulative threshold dose were not correlated (P [ .24). Higher Ara h 2especific IgE and FcεRI-positive control values were both associated with severe reactions to peanut. Combining these 2 markers led to a 92% sensitivity (84%-97%) and an 82% specificity (71%-89%) for sever

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.Peer reviewe