Extending the role of tryptase in perioperative anaphylaxis: Predicting positive results in basophil activation tests
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SUBMITTER: Mak H
PROVIDER: S-EPMC11339248 | biostudies-literature | 2024 Jul
REPOSITORIES: biostudies-literature
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Project description:BackgroundConventional data analysis of flow cytometry-based basophil activation testing requires repetitive, labor-intensive analysis that hampers efforts to standardize testing for clinical applications. Using an open-source platform, we developed and implemented a programmatic approach to the analysis of the basophil activation test (BAT) by flow cytometry.MethodsUsing the BÜHLMANN FlowCAST® assay, peripheral blood from peanut allergic patients undergoing oral immunotherapy was incubated with peanut allergens (Arah1, Arah2, Arah6, whole peanut extract) and stained with fluorescent antibodies to CCR3 and CD63 for the development of a data-driven programmatic analysis using Bioconductor and R. Basophil identification using clustering and classification was validated using manually gated comparisons in an experimental subset. Reproducibility of CD63 upregulation set on unstimulated or anti-FcERI stimulated basophils was compared.ResultsBAT analysis of 294 experiments was successful in 91.5% using the above approach, with a total of 7,166 individual basophil activation tests from 269 experiments. We estimate this represents a net saving of 1340 min of labor by a skilled operator. Medium-based gating correlated to respective manual gating more closely than anti-FcERI based gating (R = 0.96 vs. R = 0.84, P < 0.001). Only 2% of the basophil activation results were significantly different from manual gating. Quality measures of the experiments and other measures of basophil activation were also provided by the analysis.ConclusionsWe present a novel data-driven flow cytometric platform for the analysis of clinical basophil activation testing, providing a high throughput objective approach to basophil activation analysis. © 2017 International Clinical Cytometry Society.
| S-EPMC5732088 | biostudies-literature
Project description: Not available
| S-EPMC10060195 | biostudies-literature
Project description:Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a cofactor-induced wheat allergy. Gluten proteins, especially ω5-gliadins, are known as major allergens, but partially hydrolyzed wheat proteins (HWPs) also play a role. Our study investigated the link between the molecular composition of gluten or HWP and allergenicity. Saline extracts of gluten (G), gluten with reduced content of ω5-gliadins (G-ω5), slightly treated HWPs (sHWPs), and extensively treated HWPs (eHWPs) were prepared as allergen test solutions and their allergenicity assessed using the skin prick test and basophil activation test (BAT) on twelve patients with WDEIA and ten controls. Complementary sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), high-performance liquid chromatography (HPLC), and mass spectrometry (MS) analyses revealed that non-gluten proteins, mainly α-amylase/trypsin inhibitors (ATIs), were predominant in the allergen test solutions of G, G-ω5, and sHWPs. Only eHWPs contained gliadins and glutenins as major fraction. All allergen test solutions induced significantly higher %CD63+ basophils/anti-FcεRI ratios in patients compared with controls. BAT using sHWPs yielded 100% sensitivity and 83% specificity at optimal cut-off and may be useful as another tool in WDEIA diagnosis. Our findings indicate that non-gluten proteins carrying yet unidentified allergenic epitopes appear to be relevant in WDEIA. Further research is needed to clarify the role of nutritional ATIs in WDEIA and identify specific mechanisms of immune activation.
| S-EPMC8974719 | biostudies-literature
Project description:The diagnosis of drug-induced anaphylaxis (DIA) is a serious health problem. The Basophil activation test (BAT) is considered a specific in vitro provocation, and compared to in vivo provocation, it is more convenient, cheaper, and safer for the patient. This study aimed to evaluate the usefulness of the BAT in the diagnosis of DIA. This study included 150 patients referred to a reference allergy clinic with suspected drug allergies. All patients underwent a detailed clinical evaluation supplemented with the BAT. Positive BAT results were obtained in two out of 21 patients who were to receive the COVID-19 vaccine. The sensitivity and specificity of the BAT were 40% and 75% for the COVID-19 vaccine, 67% and 58% for DMG PEG 2000, and 100% and 75% for PEG 4000, respectively. Nine out of 34 patients with suspected antibiotic allergies had positive BAT results with 14 different antibiotics. Positive BAT results were also obtained with NSAIDs in two patients and with local anesthetics in three patients. The confirmation of allergy by the BAT improves the safety profile of the diagnostic work-up as it may defer the need for drug provocation, preventing potential anaphylactic reactions.
| S-EPMC11430944 | biostudies-literature
Project description:In vitro cell activation through specific IgE bound to high-affinity receptors on the basophil surface is a widely used strategy for the evaluation of IgE-mediated immediate hypersensitivity reactions to betalactams. Cellular activation requires drug conjugation to a protein to form a large enough structure displaying a certain distance between haptens to allow the cross-linking of two IgE antibodies bound to the basophil's surface, triggering their degranulation. However, no information about the size and composition of these conjugates is available. Routine in vitro diagnosis using the basophil activation test uses free amoxicillin, which is assumed to conjugate to a carrier present in blood. To standardize the methodology, we propose the use of well-controlled and defined nanomaterials functionalized with amoxicilloyl. Silica nanoparticles decorated with PAMAM-dendrimer-amoxicilloyl conjugates (NpDeAXO) of different sizes and amoxicilloyl densities (50-300 µmol amoxicilloyl/gram nanoparticle) have been prepared and chemically characterized. Two methods of synthesis were performed to ensure reproducibility and stability. Their functional effect on basophils was measured using an in-house basophil activation test (BAT) that determines CD63+ or CD203chigh activation markers. It was observed that NpDeAXO nanocomposites are not only able to specifically activate basophils but also do so in a more effective way than free amoxicillin, pointing to a translational potential diagnosis.
| S-EPMC11359297 | biostudies-literature
Project description:BackgroundAcute increases of ≥20% + 2 ng/mL (20 + 2 rule) over basal serum tryptase (BST) is the recommended threshold supporting a clinical diagnosis of anaphylaxis. Prospective studies have demonstrated high sensitivity for this algorithm after parenteral exposure, but specificity has not been evaluated.ObjectiveWe sought to define a serum tryptase change that distinguishes baseline variability from anaphylaxis on the basis of intraindividual variation in BST.MethodsNinety-three total subjects with atopy (n = 62) or hereditary α-tryptasemia (HαT) (n = 31) and ≥2 BST measurements were identified. Sequential BST variability measurements were modeled and threshold ratios that optimized sensitivity and/or specificity determined. Models were tested in 22 individuals with physician-diagnosed anaphylaxis and validated in independent cohorts of individuals with HαT (n = 33), indolent systemic mastocytosis (ISM) (n = 52), and ISM + HαT (n = 12). Mature tryptase levels were measured in HαT (n = 19) and ISM (n = 20). An online application was developed for clinical use.ResultsAs a result of BST variability, 9.7% (9/93) of primary cohort patients, and 18% (6/33) of HαT, 30% (16/53) of ISM, and 25% (3/12) of ISM + HαT patients from validation cohorts met the 20 + 2 rule despite absent immediate hypersensitivity symptoms; mature tryptase was noncontributory among individuals with HαT or ISM at baseline. A ratio of acute tryptase/BST exceeding 1.685 provided the optimized diagnostic rule for jointly maximizing sensitivity and specificity. Statistically significant improvement in specificity relative to the 20 + 2 rule was observed among individuals with elevated BST caused by HαT and ISM.ConclusionsUsing an acute tryptase/BST ratio of 1.685 improves specificity of measured changes among individuals with HαT and ISM while maintaining high sensitivity for confirmation of anaphylaxis.
| S-EPMC9126046 | biostudies-literature
Project description: Not available
| S-EPMC7807982 | biostudies-literature
Project description:BackgroundPerioperative anaphylaxis is a rare and acute systemic manifestation of drug-induced hypersensitivity reactions that occurs following anesthesia induction; the two main classes of drugs responsible for these reactions being neuromuscular blocking agents (NMBA) and antibiotics. The sensitization mechanisms to the drugs are not precisely known, and few risk factors have been described. A growing body of evidence underlines a link between occurrence of allergy and microbiota composition. However, no data exist on microbiota in perioperative anaphylaxis. The aim of this study was to compare circulating microbiota richness and composition between perioperative anaphylaxis patients and matched controls.MethodsCirculating 16s rDNA was quantified and sequenced in serum samples from 20 individuals with fully characterized IgE-mediated NMBA-related anaphylaxis and 20 controls matched on sex, age, NMBA received, type of surgery and infectious status. Microbiota composition was analyzed with a published bioinformatic pipeline and links with patients clinical and biological data investigated.ResultsAnalysis of microbiota diversity showed that anaphylaxis patients seem to have a richer circulating microbiota than controls, but no major differences of composition could be detected with global diversity indexes. Pairwise comparison showed a difference in relative abundance between patients and controls for Saprospiraceae, Enterobacteriaceae, Veillonellaceae, Escherichia-Shigella, Pseudarcicella, Rhodoferax, and Lewinella. Some taxa were associated with concentrations of mast cell tryptase and specific IgE.ConclusionWe did not find a global difference in terms of microbiota composition between anaphylaxis patient and controls. However, several taxa were associated with anaphylaxis patients and with their biological data. These findings must be further confirmed in different settings to broaden our understanding of drug anaphylaxis pathophysiology and identify predisposition markers.
| S-EPMC10808669 | biostudies-literature
Project description:BackgroundOral food challenge using gluten and cofactors is the gold standard to diagnose wheat-dependent exercise-induced anaphylaxis (WDEIA), but this procedure puts patients at risk of an anaphylactic reaction. Specific IgE to ω5-gliadins as major allergens and skin prick tests to wheat may yield negative results. Thus, we designed a proof-of-principle study to investigate the utility of the basophil activation test (BAT) for WDEIA diagnosis.MethodsDifferent gluten protein types (GPT; α-, γ-, ω1,2- and ω5-gliadins, high-molecular-weight glutenin subunits [HMW-GS] and low-molecular-weight glutenin subunits [LMW-GS]) and gluten were used in different concentrations to measure basophil activation in 12 challenge-confirmed WDEIA patients and 10 control subjects. The results were compared to routine allergy diagnostics. Parameters analyzed include the percentage of CD63+ basophils, the ratio of %CD63+ basophils induced by GPT/gluten to %CD63+ basophils induced by anti-FcεRI antibody, area under the dose-response curve and test sensitivity and specificity.ResultsGPT and gluten induced strong basophil activation for %CD63+ basophils and for %CD63+/anti-FcɛRI ratio in a dose-dependent manner in patients, but not in controls (p < 0.001, respectively). BAT performance differed from acceptable (0.73 for LMW-GS) to excellent (0.91 for ω5-gliadins) depending on the specific GPT as evaluated by the area under the receiver operating characteristic curve. Patients showed individual sensitization profiles. After determination of the best cut-off points, ω5-gliadins and HMW-GS showed the best discrimination between patients and controls with a sensitivity/specificity of 100/70 and 75/100, respectively.ConclusionThis study shows the alternative role of BAT in better defining WDEIA and the causative wheat allergens. The best BAT parameters to distinguish WDEIA patients from controls were %CD63+ basophil values for ω5-gliadins and HMW-GS.
| S-EPMC8340350 | biostudies-literature
Project description:BackgroundPerioperative anaphylaxis (PA) is a rare life-threatening complication of anesthesia, with few descriptions of its diagnosis and outcomes in the pediatric population. Many agents can be potential culprits, and drug provocation testing (DPT) to confirm the diagnosis is limited by the nature of anesthetic drugs. PA diagnosis and culprit identification remain a challenge. For patients with limited drug options, desensitization has not been reported. This study evaluated the results of skin and laboratory testing for pediatric patients with PA and provides the protocol and outcome of the first desensitization to cisatracurium, a neuromuscular blocking agent (NMBA).MethodsPatients ≤18 years old with PA from 2019 to 2024 were included, and medical records were retrospectively reviewed, which comprised serum tryptase levels, results of skin testing (ST), basophil activation testing (BAT), and outcomes.ResultsEleven patients were included. Tryptase was elevated in seven of 10 (70%) tested patients. ST yielded positive results for nine of 10 (90%), and two of 11 (18.2%) had positive BAT.ResultsA culprit agent was identified in 10 of 11 (91%). The most common drugs were NMBAs (70%) and beta-lactam antibiotics (20%). One patient with a positive DPT to NMBAs and limited alternatives was successfully desensitized to cisatracurium with a 3-bag, 12-step protocol.ConclusionThe most common drug culprits of PA in children were NMBAs and were identified by ST. Tryptase correlated with PA. BAT served as adjunctive diagnostic tests. Desensitization to cisatracurium was possible.
| S-EPMC11926948 | biostudies-literature