Relevance of low specific IgE levels to egg, milk and peanut in infancy

NOVEOS and ImmunoCAP Have Similar Performances for Diagnosing Food Allergies

BACKGROUND

The clinical significance of newly available platforms for specific IgE measurement must be evaluated. However, data are lacking for NOVEOS (Hycor), especially for food allergens.

OBJECTIVE

We compared the technical and clinical performance of two platforms (ImmunoCAP and NOVEOS) to measure specific IgE to 10 food allergens.

METHODS

Sera from 289 clinically characterized patients were tested for IgE specific for six food allergen extracts (egg white, cow's milk, peanut, hazelnut, fish, and shrimp) and four molecular allergens (Gal d 1, Bos d 8, Ara h 2, and Cor a 14). Specific IgE measurements were carried out using ImmunoCAP and NOVEOS methods. Food allergy diagnoses were established according to international guidelines.

RESULTS

A strong correlation (ρ > 0.9) was present between the two platforms whereas specific IgE concentrations measured with NOVEOS were consistently lower (mean, -15%) than with ImmunoCAP. NOVEOS and ImmunoCAP provided similar overall odds ratios and relative risks for food allergy diagnosis with both allergen extracts and molecular allergens. When all 10 allergens were considered, NOVEOS provided better receiver operating characteristic curves (P = .04). Finally, we found that the most discordant results were observed with hazelnut and peanut extracts and were related to cross-reactive carbohydrate determinants for these two with ImmunoCAP.

CONCLUSIONS

Specific IgE determination by either ImmunoCAP or NOVEOS (odds ratios of allergy, 25.1 or 33.0, respectively) is highly informative regarding the risk of allergy in the selected population. The NOVEOS platform presents the advantage of being less affected by unwanted reactivity owing to carbohydrate determinant-specific IgE while requiring a 10-fold lower test sample volume.

Allergic March in Children: The Significance of Precision Allergy Molecular Diagnosis (PAMD@) in Predicting Atopy Development and Planning Allergen-Specific Immunotherapy

The allergic march is a progression of naturally occurring symptoms whose nature changes with age. The classic allergic march typically begins in infancy and manifests in the form of atopic dermatitis and food allergy. As immune tolerance develops over time, these conditions may resolve by the age of 3-5 years; however, they may evolve into allergic rhinitis and bronchial asthma. Traditional diagnostic assessments, such as skin prick testing or serum allergen-specific immunoglobulin E (sIgE) level testing, are conducted to introduce effective treatment. Recent years saw the emergence of precision allergy molecular diagnosis (PAMD@), which assesses sIgE against allergenic molecules. This new technology helps more accurately evaluate the patient's allergy profile, which helps create more precise dietary specifications and personalize allergen-specific immunotherapy. This review presents possible predictions regarding the allergic march and the means of controlling it based on PAMD@ results.

Low Levels Matter: Clinical Relevance of Low Pru p 3 sIgE in Patients With Peach Allergy

Many clinical lab settings still use 0.35 KUA/L as the cut-off for serum specific-IgE (sIgE) immunoassays, while the detection limit is 0.1 KUA/L. The clinical relevance of -low-level sIgE (0.1–0.35 KUA/L) remains controversial. Pru p 3 sIgE is considered to be the main routine tool for assessing lipid transfer protein (LTP) sensitization. We aimed to evaluate the clinical relevance of Pru p 3 sIgE low levels in a population diagnosed with LTP allergy. Adults diagnosed with LTP allergy and Pru p 3 sIgE ≥ 0.1 KUA/L between 2012 and 2019 were included. Clinical data were reviewed. nPru p 3 basophil activation test (BAT) was performed and basophil reactivity (BR) and sensitivity (BS) correlated with the peach allergy symptoms. Pru p 3 sIgE from 496 subjects was recorded, 114 (23.0%) between 0.1 and 0.34 KUA/L (grLOW), the rest ≥ 0.35 KUA/L (grB). A total of 44.7% in grLOW and 59.9% in grB were allergic. Urticaria was more frequent in grLOW. In grLOW, Pru p 3 sIgE was higher in patients with local compared with systemic symptoms. In grB, Pru p 3 sIgE was higher in allergic patients. Pru p 3/Total IgE ratios were higher in allergic vs. tolerant in both groups. In BAT, BR was similar in both groups. In grLOW, it was higher on allergic compared with tolerant (p = 0.0286), and on those having systemic vs. local symptoms (p = 0.0286). BS showed no significant difference between groups. Patients with low levels represent a non-negligible fraction and around 45% are peach allergic. BAT showed functional sIgE in them. Pru p 3 sensitizations should be carefully evaluated even when sIgE levels are low.

Genetic effects of allergen-specific IgE levels on exhaled nitric oxide in schoolchildren with asthma: The STOPPA twin study

BACKGROUND

Exhaled nitric oxide and blood eosinophils are clinical asthma T-helper type 2 markers in use. Immunoglobulin E (IgE) is often involved in the inflammation associated with atopic asthma. The effect of both blood eosinophils and allergen-specific IgE on exhaled nitric oxide levels is not completely understood. Twin-design studies can improve understanding of the underlying contribution of genetically and/or environmentally driven inflammation markers in asthma. Our aim was to disentangle the covariance between asthma and exhaled nitric oxide into genetic and environmental contributions that can account for inflammation markers in a paediatric population.

METHODS

This population-based, cross-sectional twin study enrolled 612 monozygotic (MZ) and same-sex dizygotic (DZ) schoolchildren. Multivariate structural equation modelling was utilized to separate the covariance between asthma and exhaled nitric oxide into genetic and/or environmental effects, taking allergen-specific IgE level and blood eosinophil count into account while controlling for confounding factors.

RESULTS

The cross-twin/cross-trait correlations had a higher magnitude in the MZ twins than in the DZ twins, indicating that genes affect the association. The likelihood ratio test for model fitting resulted in the AE model (ie additive genetic effects, A, and non-shared environmental effects, E) as the most parsimonious. A majority, 73%, of the phenotypic correlation between asthma and exhaled nitric oxide, r = .19 (0.05-0.33), was attributable to genetic effects which mainly was due to the allergen-specific IgE level.

CONCLUSIONS

This study indicates that the association between asthma and exhaled nitric oxide in children is to a large extent explained by genetics via allergen-specific IgE level and not blood eosinophils. This might partly explain the clinical heterogeneity in this group. A next step could be to include allergen-specific IgE level in multivariate omic studies.

Allergic sensitization among Danish infants at 13 months of age

Background

Sensitization means elevated number of specific immunoglobulin E, either measured by skin prick test or in blood samples. Sensitization is associated with, but not synonymous with, allergic disease.

Methods

The Danish Calmette Study was conducted from 2012 to 2015 at three Danish hospitals, with the aim of exploring nonspecific effects of neonatal Bacillus Calmette‐Guérin vaccination. Participants at Kolding Hospital were invited to have a blood sample analyzed for allergic sensitization at 13 months of age. Telephone interviews gave information about allergic symptoms, and the children were examined for signs of atopic dermatitis at 3 and 13 months.

Results

Of the 1241 children included in the Danish Calmette Study in Kolding 1066 (86%) had a blood sample drawn, representing 36% of the invited families. The blood sample cohort had a relatively high percentage of atopic predisposition (66.6%) and most mothers had a medium or long education. We found 90 infants (8.4%) to be sensitized, with sensitization against food items (milk, egg, peanut, and hazelnut) being the most common. Atopic dermatitis was found in 19% of the children, and it was significantly associated with sensitization against egg, peanut, wheat, cat, and dog.

Conclusion

In a partly selected Danish cohort, sensitization was present in 8% at 13 months of age, especially sensitization against food items. Children with atopic dermatitis were significantly more sensitized (16.6%). However, most sensitized children did not have any allergic symptoms at this age.