Comparison of specific IgE against allergen components measured on the ALEX2® Allergy Xplorer and the ImmunoCAPTM ISAC multiplex assays

Background. Allergic disease, mediated by immunoglobulin E (IgE), is common worldwide and its incidence is on the rise. Objectives. To compare common food, inhalant and cross-reactive molecular components detected by the ImmunoCAP Immuno Solid- phase Allergen Chip (ISACTM) and the Allergy Xplorer (ALEX2®) multiplex IgE assays. Methods. The study analysed serum samples from 100 patients with suspected allergies. Allergen-specific IgE (sIgE) molecular component measurements were performed using the ImmunoCAPTM ISAC E112i assay (ISACTM) (Thermo Fisher Scientific, Sweden). Subsequently, sIgE molecular component measurements were performed using the Allergy Xplorer 2® (ALEX2®) (Macro Array Diagnostics, Austria). The ISACTM method tests 112 molecular allergen components. The ALEX2® method offers 295 reportable molecular allergen components and whole allergen extracts. Results. The overall Kappa analysis showed very good agreement in 58.33% (n=28/48) of components, good agreement in 33.33% (n=16/48) of components, moderate agreement in 8.33% (n=4/48) of components and no fair or poor agreements seen among the analysed components. The four components with a moderate agreement were Gly m 4 (PR-10, soy), Ara h 8 (PR-10, peanut), Gly m 5 (storage protein, soy) and Tri aA/TI (alpha amylase/TI, wheat), with K values of 0.52, 0.51, 0.48 and 0.44, respectively. Tri-AA/TI exhibited the lowest agreement. Conclusions. The study findings demonstrated a good correlation between the ALEX2® and ISACTM assays for the detection of sIgE against molecular allergen components. ALEX2® offers the benefit of testing 295 molecular allergen components and extracts, as well as cross- reactive carbohydrate determinants (CCD) inhibition.