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.

Molecular allergology: a clinical laboratory tool for precision diagnosis, stratification and follow-up of allergic patients

Identification of the molecular culprits of allergic reactions leveraged molecular allergology applications in clinical laboratory medicine. Molecular allergology shifted the focus from complex, heterogeneous allergenic extracts, e.g. pollen, food, or insect venom, towards genetically and immunologically defined proteins available for in vitro diagnosis. Molecular allergology is a precision medicine approach for the diagnosis, stratification, therapeutic management, follow-up and prognostic evaluation of patients within a large range of allergic diseases. Exclusively available for in vitro diagnosis, molecular allergology is nonredundant with any of the current clinical tools for allergy investigation. As an example of a major application, discrimination of genuine sensitization from allergen cross-reactivity at the molecular level allows the proper targeting of the culprit allergen and thus dramatically improves patient management. This review aims at introducing clinical laboratory specialists to molecular allergology, from the biochemical and genetic bases, through immunological concepts, to daily use in the diagnosis and management of allergic diseases.

A singleplex IgE test to a mixture of molecules from multiple airborne allergen sources: Innovating in vitro screening of respiratory allergies

BACKGROUND

In vitro immunoglobulin E (IgE) tests can be better standardized if based on molecules rather than extracts. However, singleplex screening tests for respiratory or food allergies are still based on extracts only.

TARGET

To validate a novel singleplex IgE screening test for respiratory allergies, based on a mix of major allergenic molecules Der p 1, Der p 2, Fel d 1, Can f 1, Can f 2, Can f 3, Can f 5, Bet v 1, Phl p 1, and Art v 1 (Molecular SX01, NOVEOS, HYCOR, USA), and requiring only four microliters (μl) of serum.

METHODS

We examined six subsets of sera from participants of the German Multicenter Allergy Study (MAS) birth cohort enrolling 1314 newborns during 1990: (1) monosensitized (n = 58); (2) polysensitized (n = 24); (3) nonsensitized, with total IgE levels above (n = 24) or (4) below (n = 24) 300 kU/L; (5) sensitized to milk and/or egg but not to airborne allergens (n = 24); and (6) sera of children aged ≤5 years at their earliest IgE monosensitization to airborne allergens (n = 41). Sera were analyzed with the novel molecular SX01 test (NOVEOS) and with three categories of comparators: ImmunoCAP Phadiatop SX01, extracts, and molecules of D. pteronyssinus, cat, dog, grass, and birch. Sensitivity, specificity, positive and negative predictive values were calculated. Quantitative interrelationships were determined using Spearman's rank-order correlation coefficient and Bland-Altmann plots.

RESULTS

The molecular SX01 test predicted the outcome of IgE tests based on molecules, extracts, or Phadiatop in 188 (96.4%), 171 (87.7%), and 171 (87.7%) of the 195 sera, respectively. Accordingly, sensitivity was 93.5%, 89.0%, and 82.4%, whereas specificity was 100%, 97.6%, and 96.1% when compared with molecular, extract, and Phadiatop tests, respectively. Inconsistent outcomes were largely confined to sera with IgE-Ab levels around the cutoff value of 0.35 kU/L, except for 5/195 (2.5%) sera, containing high levels of IgE to Phl p 5 and/or Alt a 1 only. IgE levels measured by the molecular SX01 test and with IgE tests to molecules, extracts, and Phadiatop were highly correlated (rho 0.90; p < .001), (rho 0.87, p < .001), (rho 0.84, p < .001), respectively. The novel molecular SX01 test detected IgE-Ab in 27/28 (sensitivity 96.4%) of the sera of preschool children at their earliest IgE sensitization to the same molecules.

DISCUSSION

Our study validates the prototype of a novel category of IgE test, based on molecular mixes. The test's rather good precision and accuracy in early screening IgE sensitization to airborne allergens in German children may be further improved by adding a few other molecules, such as Phl p 5 and Alt a 1.