Validation of the new microarray platform ALEX for specific IgE
detection of respiratory and plant-food allergens
Abstract
Background: As the use of multiplex specific IgE (sIgE) detection
methods becomes increasingly widespread, proper comparative validation
assessments of emerging new platforms are vital. The objective of this
study was to assess the clinical and technical performance of the ALEX
platform (MacroArray Diagnostics), in comparison to the ImmunoCAP ISAC
112 microarray and the ImmunoCAP singleplex method (ThermoFisher
Scientific) in the diagnosis of pollen (cypress, grass, olive), dust
mite Dermatophagoides pteronyssinus, Alternaria alternata, fruit (apple,
peach) and nut (walnut, hazelnut and peanut) allergy. Methods: We
enrolled 153 allergic patients and 16 non-atopic controls. sIgE assays
were conducted using ISAC112, ALEX version 2 (ALEX2), and ImmunoCAP for
whole extracts and major components. Technical validation of ALEX2 was
performed by measuring repeatability and inter-assay, inter-batch and
inter-lab reproducibility. Results: When measured globally (detection by
one or more allergen components), ALEX2 showed adequate sensitivity and
specificity for most of the allergens studied, comparable in general to
that of ISAC112 (except for olive pollen and walnut) and similar to that
of ImmunoCAP whole extract measurements. Component-by-component analysis
showed comparable results for all techniques, except for Ole e 1 and Jug
r 3 in both ISAC112 and ImmunoCAP comparisons, and Alt a 1, when
compared with ISAC112. Continuous sIgE levels correlate with sIgE by
ImmunoCAP. Good reproducibility and repeatability were observed for
ALEX2. Conclusions: ALEX2 shows sound technical performance, and
adequate diagnostic capacity, comparable in general to that of ISAC112
and ImmunoCAP for some aeroallergens and plant-food allergies in
Mediterranean patients.