Project description:Plant-food allergy is an increasing problem, with nonspecific lipid transfer proteins (nsLTPs) triggering mild/severe reactions. Pru p 3 is the major sensitizer in LTP food allergy (FA). However, in vivo and in vitro diagnosis is hampered by the need for differentiating between asymptomatic sensitization and allergy with clinical relevance. The basophil activation test (BAT) is an ex vivo method able to identify specific IgE related to the allergic response. Thus, we aimed to establish the value of BAT in a precise diagnosis of LTP-allergic patients. Ninety-two individuals with peach allergy sensitized to LTP, Pru p 3, were finally included, and 40.2% of them had symptoms to peanut (n = 37). In addition, 16 healthy subjects were recruited. BAT was performed with Pru p 3 and Ara h 9 (peanut LTP) at seven ten-fold concentrations, and was evaluated by flow cytometry, measuring the percentage of CD63 (%CD63+) and CD203c (%CD203chigh) cells, basophil allergen threshold sensitivity (CD-Sens), and area under the dose-response curve (AUC). Significant changes in BAT parameters (%CD63+ and %CD203chigh) were found between the controls and patients. However, comparisons for %CD63+, %CD203chigh, AUC, and CD-Sens showed similar levels among patients with different symptoms. An optimal cut-off was established from ROC curves, showing a significant positive percentage of BAT in patients compared to controls and great values of sensitivity (>87.5%) and specificity (>85%). In addition, BAT showed differences in LTP-allergic patients tolerant to peanut using its corresponding LTP, Ara h 9. BAT can be used as a potential diagnostic tool for identifying LTP allergy and for differentiating peanut tolerance, although neither reactivity nor sensitivity can distinguish the severity of the clinical symptoms.
Project description:BackgroundMost of the peanut-sensitized children do not have clinical peanut allergy. In equivocal cases, oral food challenges (OFCs) are required. However, OFCs are laborious and not without risk; thus, a test that could accurately diagnose peanut allergy and reduce the need for OFCs is desirable.ObjectiveTo assess the performance of basophil activation test (BAT) as a diagnostic marker for peanut allergy.MethodsPeanut-allergic (n = 43), peanut-sensitized but tolerant (n = 36) and non-peanut-sensitized nonallergic (n = 25) children underwent skin prick test (SPT) and specific IgE (sIgE) to peanut and its components. BAT was performed using flow cytometry, and its diagnostic performance was evaluated in relation to allergy versus tolerance to peanut and validated in an independent population (n = 65).ResultsBAT in peanut-allergic children showed a peanut dose-dependent upregulation of CD63 and CD203c while there was no significant response to peanut in peanut-sensitized but tolerant (P < .001) and non-peanut-sensitized nonallergic children (P < .001). BAT optimal diagnostic cutoffs showed 97% accuracy, 95% positive predictive value, and 98% negative predictive value. BAT allowed reducing the number of required OFCs by two-thirds. BAT proved particularly useful in cases in which specialists could not accurately diagnose peanut allergy with SPT and sIgE to peanut and to Arah2. Using a 2-step diagnostic approach in which BAT was performed only after equivocal SPT or Arah2-sIgE, BAT had a major effect (97% reduction) on the number of OFCs required.ConclusionsBAT proved to be superior to other diagnostic tests in discriminating between peanut allergy and tolerance, particularly in difficult cases, and reduced the need for OFCs.
Project description:PURPOSE:The basophil activation test (BAT) has been reported to be useful for the diagnosis of various food allergies, such as allergy to peanut, but not to fish. This study aimed to evaluate the diagnostic performance of the BAT for fish allergy. METHODS:We performed a retrospective review of patients with fish allergy who underwent the BAT using a panel of fish extracts (15 kinds) to examine the differential reactivity to several species of fish. The BAT score for each extract was expressed as the ratio of CD203chigh% with the extract to that with anti-IgE antibody. Clinical reactivity to each fish was confirmed by positive oral food challenge or a typical history of fish-induced immediate allergy symptoms. Receiver-operating-characteristic (ROC) analysis was performed to evaluate the diagnostic performance. RESULTS:Fifty-one patients with fish allergy were analyzed. Using extracts of 15 species of fish, the BAT was performed a total of 184 times on the patients. Clinical allergy to each species of fish was confirmed in 90 (48.9%) of those tests. ROC analysis yielded high areas under the curve for the BAT scores for the 5 most common fish species (0.72-0.88). The diagnostic accuracy ranged from 0.74 to 0.86. Using a tentative cutoff value of 0.3 deduced from the ROC analyses of the 5 fish species, the accuracy for other fish allergic reactions was generally high (0.6-1.0), except the fish tested in a small number of patients. CONCLUSIONS:The BAT score based on CD203c expression may be useful for fish allergy diagnosis, especially since a large variety of fish can be tested by the BAT using fish extracts prepared by a simple method.
Project description:Alpha-gal (AG) allergy is an IgE-mediated allergic reaction to galactose-alpha-1,3-galactose found in mammalian meat. Heparin, being derived from porcine intestinal tissue, may have a degree of cross-reactivity with AG antigen and thus place patients at risk for allergic and even anaphylactic reactions. This is especially important in patients with myocardial infarction (MI) and mechanical circulatory support, such as a left ventricular assist device (LVAD), since anticoagulation is immediately required. Therefore, individualized assessment and preoperative planning is needed regarding the use of heparin vs. nonheparinoid products in such a population.
Project description:BackgroundPeanut and tree nut allergies are the most important causes of anaphylaxis. Co-reactivity to more than one nut is frequent, and co-sensitization in the absence of clinical data is often obtained. Confirmatory oral food challenges (OFCs) are inconsistently performed.ObjectiveTo investigate the utility of the basophil activation test (BAT) in diagnosing peanut and tree nut allergies.MethodsThe Markers Of Nut Allergy Study (MONAS) prospectively enrolled patients aged 0.5-17 years with confirmed peanut and/or tree nut (almond, cashew, hazelnut, pistachio, walnut) allergy or sensitization from Canadian (n = 150) and Austrian (n = 50) tertiary pediatric centers. BAT using %CD63+ basophils (SSClow/CCR3pos) as outcome was performed with whole blood samples stimulated with allergen extracts of each nut (0.001-1000 ng/mL protein). BAT results were assessed against confirmed allergic status in a blinded fashion to develop a generalizable statistical model for comparison to extract and marker allergen-specific IgE.ResultsA mixed effect model integrating BAT results for 10 and 100 ng/mL of peanut and individual tree nut extracts was optimal. The area under the ROC curve (AUROC) was 0.98 for peanut, 0.97 for cashew, 0.92 for hazelnut, 0.95 for pistachio, and 0.97 for walnut. The BAT outperformed sIgE testing for peanut or hazelnut and was comparable for walnut (AUROC 0.95, 0.94, 0.92) in a sub-analysis in sensitized patients undergoing OFC.ConclusionsBasophil activation test can predict allergic clinical status to peanut and tree nuts in multi-nut-sensitized children and may reduce the need for high-risk OFCs in patients.
Project description:BackgroundJAK1 is a signaling molecule downstream of cytokine receptors, including IL-4 receptor α. Abrocitinib is an oral JAK1 inhibitor; it is a safe and effective US Food and Drug Administration-approved treatment for adults with moderate-to-severe atopic dermatitis.ObjectiveOur objective was to investigate the effect of abrocitinib on basophil activation and T-cell activation in patients with peanut allergy to determine the potential for use of JAK1 inhibitors as a monotherapy or an adjuvant to peanut oral immunotherapy.MethodsBasophil activation in whole blood was measured by detection of CD63 expression using flow cytometry. Activation of CD4+ effector and regulatory T cells was determined by the upregulation of CD154 and CD137, respectively, on anti-CD3/CD28- or peanut-stimulated PBMCs. For the quantification of peanut-induced cytokines, PBMCs were stimulated with peanut for 5 days before harvesting supernatant.ResultsAbrocitinib decreased the allergen-specific activation of basophils in response to peanut. We showed suppression of effector T-cell activation when stimulated by CD3/CD28 beads in the presence of 10 ng of abrocitinib, whereas activation of regulatory T-cell populations was preserved in the presence of abrocitinib. Abrocitinib induced statistically significant dose-dependent inhibition in IL-5, IL-13, IL-10, IL-9, and TNF-α in the presence of peanut stimulation.ConclusionThese results support our hypothesis that JAK1 inhibition decreases basophil activation and TH2 cytokine signaling, reducing in vitro allergic responses in subjects with peanut allergy. Abrocitinib may be an effective adjunctive immune modulator in conjunction with peanut oral immunotherapy or as a monotherapy for individuals with food allergy.