Clinical utility analysis of the Hoxb8 mast cell activation test for the diagnosis of peanut allergy.

BACKGROUND: Peanut allergy is among the most severe and common food allergies. The diagnosis has a significant impact on the quality of life for patients and their families. An effective management approach depends on accurate, safe, and easily implementable diagnostic methods. We previously developed a cell-based assay using Hoxb8 mast cells (Hoxb8 MCs) aimed at improving clinical allergy diagnosis. In this study, we assessed its diagnostic performance by measuring blinded sera from a prospectively enrolled and pre-validated peanut allergy cohort. METHODS: Hoxb8 MCs were passively sensitized with sera from peanut-allergic and peanut tolerant children and adolescents (n = 112). Degranulation of Hoxb8 MCs was quantified upon stimulation with dose-titrated peanut extract by means of flow cytometry, using CD107a as activation marker. The results from the Hoxb8 mast cell activation test (Hoxb8 MAT) were compared to established diagnostic assays such as the skin prick test (SPT), specific IgE (sIgE) levels, and the basophil activation test (BAT). Additionally, serum samples from BAT nonresponders were assessed with the Hoxb8 MAT. RESULTS: Hoxb8 MAT displayed a robust dose-dependent activation to peanut extract, with a cutoff value of ≤5.2% CD107a positive cells. The diagnostic accuracy was highest at allergen concentrations ≥100 ng/mL, with an area under the receiver operating characteristic curve (AUROC) of 0.97, 93% sensitivity, and 96% specificity, outperforming traditional SPT and sIgE tests. When compared to BAT, Hoxb8 MAT exhibited comparable diagnostic efficacy. Moreover, sera from BAT nonresponders were accurately classified into allergics and nonallergics by the Hoxb8 MAT. CONCLUSIONS: The Hoxb8 MAT demonstrated a very good diagnostic precision in patients prospectively assessed for peanut allergy comparable to the fresh whole blood-based BAT. Additionally, it demonstrated its value for accurate classification of BAT nonresponders into allergic and nonallergic individuals. Further investigations into its utility in the routine clinical setting are warranted.

An update on recent developments and highlights in food allergy.

While both the incidence and general awareness of food allergies is increasing, the variety and clinical availability of therapeutics remain limited. Therefore, investigations into the potential factors contributing to the development of food allergy (FA) and the mechanisms of natural tolerance or induced desensitization are required. In addition, a detailed understanding of the pathophysiology of food allergies is needed to generate compelling, enduring, and safe treatment options. New findings regarding the contribution of barrier function, the effect of emollient interventions, mechanisms of allergen recognition, and the contributions of specific immune cell subsets through rodent models and human clinical studies provide novel insights. With the first approved treatment for peanut allergy, the clinical management of FA is evolving toward less intensive, alternative approaches involving fixed doses, lower maintenance dose targets, coadministration of biologicals, adjuvants, and tolerance-inducing formulations. The ultimate goal is to improve immunotherapy and develop precision-based medicine via risk phenotyping allowing optimal treatment for each food-allergic patient.

Beyond Laryngeal Clefts: Interarytenoid Injection Augmentation to Predict Success of Suture Augmentation in Children.

OBJECTIVE: To assess the efficacy of interarytenoid injection augmentation (IAIA) and the ability of IAIA to predict response to interarytenoid suture augmentation (IASA) based on diet advancement on video fluoroscopic swallow studies (VFSS). METHODS: Retrospective cohort analysis of patients with persistent pharyngeal dysphagia at a tertiary children's hospital with VFSS pre- and post-IAIA were included between March 2011 and June 2019. RESULTS: Median age of the 229 patients was 2.2 years (5.8 months-19 years). Interarytenoid mucosal height (IAMH) was found to be above the false vocal folds in 112 patients (53.4%) and at true vocal folds in 10 (4.9%) patients. On VFSS post-IAIA, 95 (41.5%) patients were successfully advanced in recommended diet consistency, 115 (50.2%) were stable, and 19 (8.3%) needed thicker consistency. Paired t-tests on pre- and post-operative consistency scores showed significant improvement, p-value of <0.0001, 95% confidence interval (CI; 0.50-0.85). Poisson regression found no covariates with significant association with improvement on IAIA. For IASA patients, 35/60 (58.3%) improved on post-op VFSS. Paired t-tests on pre- and post-operative consistency scores showed significant improvement, p-value of <0.0001, 95% CI (0.63-1.33). Positive predictive value for IAIA predicting response to IASA was 77% with positive likelihood ratio of 2.3. The response to IAIA versus no response to IAIA likelihood ratios were found to have a statistically significant difference (p < 0.05). CONCLUSIONS: Our study suggests IAIA yields objective improvement in swallow function on VFSS in nearly half of our patients and may be a reliable diagnostic tool to predict response to IASA in patients with persistent pharyngeal dysphagia with or without a laryngeal cleft. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:1749-1756, 2023.

Optimal sequence-based design for multi-antigen HIV-1 vaccines using minimally distant antigens.

The immense global diversity of HIV-1 is a significant obstacle to developing a safe and effective vaccine. We recently showed that infections established with multiple founder variants are associated with the development of neutralization breadth years later. We propose a novel vaccine design strategy that integrates the variability observed in acute HIV-1 infections with multiple founder variants. We developed a probabilistic model to simulate this variability, yielding a set of sequences that present the minimal diversity seen in an infection with multiple founders. We applied this model to a subtype C consensus sequence for the Envelope (Env) (used as input) and showed that the simulated Env sequences mimic the mutational landscape of an infection with multiple founder variants, including diversity at antibody epitopes. The derived set of multi-founder-variant-like, minimally distant antigens is designed to be used as a vaccine cocktail specific to a HIV-1 subtype or circulating recombinant form and is expected to promote the development of broadly neutralizing antibodies.

Platelet-activating factor acetylhydrolase is a biomarker of severe anaphylaxis in children.

BACKGROUND: There is limited ability to predict the severity of allergic reactions in children. Data derived predominantly from adults have implicated the platelet-activating factor pathway as a potential contributor to severe anaphylaxis. In this study, we sought to prospectively assess involvement of key components of the platelet-activating factor pathway in pediatric patients with anaphylaxis. METHODS: Forty-six pediatric patients (<18 years) presenting with acute anaphylaxis were assessed. Anaphylaxis severity was graded and serum anaphylaxis markers were measured acutely and in 36 children who returned for follow-up >4 weeks after their acute presentation. These markers were compared with pediatric laboratory reference sera. RESULTS: Severe anaphylaxis was experienced by 12/46 (26%) and mild-moderate anaphylaxis in 34/46 (74%) children. Platelet-activating factor acetylhydrolase (PAF-AH) activity was inversely associated with severe anaphylaxis: 9/12 children with severe anaphylaxis had reduced PAF-AH activity as compared with 14/34 with mild-moderate anaphylaxis (p < .05). Furthermore, 3/3 children who required intensive care had markedly reduced mean PAF-AH (nmol/ml/min) (13.73, 95%CI: 7.42-20.03) versus 20/23 who required ward/emergency department care (17.81, 95%CI: 16.80-18.83; p < .05). In children with anaphylaxis, PAF-AH during acute anaphylaxis was unchanged relative to the child's basal levels (mean, 17.26, 95%CI: 16.10-18.42 vs 17.50, 95%CI: 16.21-18.78, p = .63) and was lower than healthy pediatric controls (mean 19.21; 95%CI:18.21-20.21; p < .05). CONCLUSION: Decreased serum PAF-AH activity is a biomarker of severe anaphylaxis. Levels of this enzyme do not change from basal levels during acute anaphylaxis. Our results show that PAF-AH is a biomarker of anaphylaxis severity in children. This key regulatory enzyme may modulate susceptibility to severe anaphylaxis.

Modeling the conversion between specific IgE test platforms for nut allergens in children and adolescents.

BACKGROUND: Multiplex tests allow for measurement of allergen-specific IgE responses to multiple extracts and molecular allergens and have several advantages for large cohort studies. Due to significant methodological differences, test systems are difficult to integrate in meta-analyses/systematic reviews since there is a lack of datasets with direct comparison. We aimed to create models for statistical integration of allergen-specific IgE to peanut/tree nut allergens from three IgE test platforms. METHODS: Plasma from Canadian and Austrian children/adolescents with peanut/tree nut sensitization and a cohort of sensitized, high-risk, pre-school asthmatics (total n = 166) were measured with three R&D multiplex IgE test platforms: Allergy Explorer version 1 (ALEX) (Macro Array Dx), MeDALL-chip (Mechanisms of Development of Allergy) (Thermo Fisher), and EUROLINE (EUROIMMUN). Skin prick test (n = 51) and ImmunoCAP (Thermo Fisher) (n = 62) results for extracts were available in a subset. Regression models (Multivariate Adaptive Regression Splines, local polynomial regression) were applied if >30% of samples were positive to the allergen. Intra-test correlations between PR-10 and nsLTP allergens were assessed. RESULTS: Using two regression methods, we demonstrated the ability to model allergen-specific relationships with acceptable measures of fit (r2  = 94%-56%) for peanut and tree nut sIgE testing at the extract and molecular-level, in order from highest to lowest: Ara h 2, Ara h 6, Jug r 1, Ana o 3, Ara h 1, Jug r 2, and Cor a 9. CONCLUSION: Our models support the notion that quantitative conversion is possible between sIgE multiplex platforms for extracts and molecular allergens and may provide options to aggregate data for future meta-analysis.

Basophil activation test shows high accuracy in the diagnosis of peanut and tree nut allergy: The Markers of Nut Allergy Study.

BACKGROUND: Peanut 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. OBJECTIVE: To investigate the utility of the basophil activation test (BAT) in diagnosing peanut and tree nut allergies. METHODS: The 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. RESULTS: A 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. CONCLUSIONS: Basophil 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.

Pediatric dysphagia: Is interarytenoid mucosal height significant?

OBJECTIVES: The clinical significance of the interarytenoid mucosal height (IAMH) in pediatric dysphagia, ranging from normal anatomy to a laryngeal cleft, is unknown. This study seeks to evaluate a cohort of patients who underwent evaluation of their IAMH during microdirect laryngoscopy (MDL) for associations between IAMH and dysphagia as diagnosed on preoperative videofluoroscopic swallow study (VFSS). METHODS: A retrospective case series of 1,351 patients who underwent MDL between 2011 and 2016 were reviewed for intraoperative evaluation of IAMH using our interarytenoid assessment protocol. After exclusions, 182 patients were divided into three groups: 1) thickened diet: VFSS with recommendation for thickened liquids (n = 82 of 182; 45.1%), 2) normal diet: VFSS with allowance of thin liquids (n = 19 of 182; 10.4%), and 3) control: no VFSS performed (n = 81 of 182; 44.5%). RESULTS: There was no difference in IAMH between groups (P = 0.35). Power analysis was able to achieve > 80% power to detect an effect size of ≥ 0.5 (1-5 mucosal height scale). The majority of patients in each group had an IAMH above the false vocal folds (thickened diet: 57.3%, normal diet: 57.9%, control: 64.2%). There were similar percentages of patients in each group with an IAMH at or below the true vocal folds (thickened diet: 4.9%, normal diet: 5.3%, control: 6.1%). CONCLUSION: There was no significant association between IAMH and preoperative thickened liquid recommendation in this cohort. This data fails to support the hypothesis that the IAMH is an independent etiological factor for pediatric pharyngeal dysphagia. Further studies comparing IAMH with outcomes after feeding therapy and surgery may better clarify this relationship between anatomy and physiology. LEVEL OF EVIDENCE: 4. Laryngoscope, 129:2588-2593, 2019.

A pilot study assessing clinic value in pediatric pharyngeal dysphagia: The OPPS/cost method.

OBJECTIVES/HYPOTHESIS: Given the costs of healthcare, capitation, and desires for quality improvement (QI), there is a need to better assess healthcare value. Time-driven activity-based costing and the Quadruple Aim have evaluated value by assessing health outcomes and provider experiences relative to costs. The proposed OPPS/Cost method expands on this to examine value for aerodigestive clinic treatment of pediatric persistent pharyngeal dysphagia: O + P1 + P2 + S/Cost (O = objective health [video-fluoroscopic swallow study results], P1 = patient/family experience [Consumer Assessment of Healthcare Providers and Systems], P2 = provider experience [Copenhagen Burnout Inventory {CBI}], S = subjective health [Feeding/Swallowing-Impact Survey], C = cost [time-driven activity-based costing]). STUDY DESIGN: Use of QI time data, surveys, and retrospective chart review for 56 patient encounters. METHODS: Staff interviews were used to develop process maps, and monetary values were assigned to activities. OPPS/Cost outcomes were normalized amongst variables, and composite values were calculated. Comparisons were made using a Student t test for pre- and postclinic relocation over a 14-month period. RESULTS: Time reductions were check-in (13 minutes/patient), rooming (21 minutes/patient), and providers (4 minutes/patient). Patient in-room wait time increased (4 minutes/patient). The CBI identified burnout as an area for improvement. OPPS/Cost composite values increased by 14%, with a 1.7% cost reduction, improvement in objective and subjective health outcomes of 47.4% (P < .05) and 7.3%, respectively, and stable patient/family experience. CONCLUSIONS: OPPS/Cost is feasible in an interdisciplinary clinic and helped evaluate value during a clinic relocation. The QI opportunities identified are indicative of the potential of OPPS/Cost. LEVEL OF EVIDENCE: NA Laryngoscope, 129:1527-1532, 2019.