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.

Child and Maternal Factors Associated with Feeding Practices in Children with Poor Growth.

The development of adequate growth and healthy eating behaviors depends on nutritious food and responsive feeding practices. Our study examined (1) the relationship between maternal concern about child weight or perceived feeding difficulties and their feeding practices, and (2) the moderating role of child temperament and maternal mental health on their feeding practices. A cross-sessional study included mother-child dyads (n = 98) from a tertiary growth and feeding clinic. Children had a mean age of 12.7 ± 5.0 months and a mean weight-for-age z-score of -2.0 ± 1.3. Responsive and controlling feeding practices were measured with the Infant Feeding Styles Questionnaire. Spearman correlation and moderation analysis were performed. Maternal concern about child weight and perceived feeding difficulties were negatively correlated with responsive feeding (r = -0.40, -0.48, p < 0.001). A greater concern about child weight or perceived feeding difficulties was associated with greater use of pressure feeding practices when effortful control was low (B = 0.49, t = 2.47, p = 0.01; B = -0.27, p = 0.008). Maternal anxiety had a significant moderation effect on the relationship between feeding difficulty and pressure feeding (B = -0.04, p = 0.009). Higher maternal concern about child weight and perceived feeding difficulties were associated with less responsive satiety feeding beliefs and behaviors. Both child effortful control and maternal anxiety influenced the relationship between weight and feeding concerns and the use of pressure feeding practices.

Biopsychosocial Factors in Children Referred With Failure to Thrive: Modern Characterization for Multidisciplinary Care.

The objective of this study was to characterize biopsychosocial characteristics in children with failure to thrive with a focus on 4 domains: medical, nutrition, feeding skills, and psychosocial characteristics. A retrospective cross-sectional chart review was conducted of children assessed at the Infant and Toddler Growth and Feeding Clinic from 2015 to 2016. Descriptive statistics were used to analyze the data. One hundred thirty-eight children, 53.6% male, mean age 16.9 months (SD = 10.8), were included. Approximately one quarter of the children had complex medical conditions, medical comorbidities, and developmental delays. The mean weight-for-age percentile was 15.5 (SD = 23.9), and mean weight-for-length z score was -1.51 (SD = 1.4). A total of 22.5% of children had delayed oral-motor skills and 28.3% had oral aversion symptoms. Caregiver feeding strategies included force feeding (14.5%) and the use of distractions (47.1%). The multifactorial assessment of failure to thrive according to the 4 domains allowed for a better understanding of contributing factors and could facilitate multidisciplinary collaboration.