title: Performance of a polymer coated silicon microarray for simultaneous detection of food allergen-specific IgE and IgG4.
abstract: BACKGROUND
  Microarray-based component-resolved diagnostics (CRD) has become an accepted tool to detect allergen-specific IgE sensitization towards hundreds of allergens in parallel from one drop of serum. Nevertheless, specificity and sensitivity as well as a simultaneous detection of allergen-specific IgG4, as a potential parameter for tolerance development, remain to be optimized.
  
  
  OBJECTIVE
  We applied the recently introduced silicon chip coated with a functional polymer named copoly(DMA-NAS-MAPS) to the simultaneous detection of food allergen-specific IgE and IgG4, and compared it with ImmunoCAP and ImmunoCAP ISAC. Inter- and intraslide variation, linearity of signal and working range, sensitivity and application of internal calibrations for IgE and IgG4were assessed.
  
  
  METHODS
  Native and recombinant allergenic proteins from hen's egg and cow's milk were spotted on silicon chips coated with copoly(DMA-NAS-MAPS) along with known concentrations for human IgE and IgG4. A serum pool and 105 patient samples were assessed quantitatively and semi-quantitatively with the ImmunoCAP and ImmunoCAP ISAC and correlated with IgE- and IgG4-specific fluorescence on silicon microarrays.
  
  
  RESULTS
  Allergen-specific IgE and IgG4were detected in parallel using two fluorescent dyes with no crosstalk. Results from the ImmunoCAP correlated better with microarray fluorescence than with ImmunoCAP ISAC except for the allergen ovomucoid. The working range of the silicon microarray for total hen's egg-specific IgE was comparable to the range of 0.1 to >100 kUA/L of the ImmunoCAP system, whereas for total cow's milk, the silicon microarray was less sensitive. Detectable allergen-specific IgG4could be determined only for low concentrations, but still correlated positively with ImmunoCAP results.
  
  
  CONCLUSIONS
  We confirmed the ability of the polymer coated silicon microarray to be comparably sensitive to the ImmunoCAP ISAC for various food allergens. This suggests that the copoly(DMA-NAS-MAPS) microarray is a low-cost, self-producible alternative to the commercial ImmunoCAP ISAC in allergy research.
authors.affiliation: Pediatric Pneumology and Immunology, Charité Universitätsmedizin, Berlin, Germany.|Department of Biology, Chemistry and Pharmacy, Free University, Berlin, Germany.
authors.forename: S
authors.identifier: http://orcid.org/0000-0002-4265-1974
authors.initials: S
authors.lastname: Sievers
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare (ICRM), Consiglio Nazionale delle Ricerche, Milano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cretich
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare (ICRM), Consiglio Nazionale delle Ricerche, Milano, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Gagni
authors.affiliation: Pediatric Pneumology and Immunology, Charité Universitätsmedizin, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Ahrens
authors.affiliation: Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: G
authors.initials: G
authors.lastname: Grishina
authors.affiliation: Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Sampson
authors.affiliation: Pediatric Pneumology and Immunology, Charité Universitätsmedizin, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Niggemann
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare (ICRM), Consiglio Nazionale delle Ricerche, Milano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Chiari
authors.affiliation: Pediatric Pneumology and Immunology, Charité Universitätsmedizin, Berlin, Germany.|Icahn School of Medicine at Mount Sinai, New York, NY, USA.
authors.forename: K
authors.initials: K
authors.lastname: Beyer
mesh_terms: D021181:Egg Hypersensitivity / Q000097:blood* / Q000276:immunology; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood* / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D008297:Male; D016269:Milk Hypersensitivity / Q000097:blood* / Q000276:immunology; D040081:Protein Array Analysis / Q000295:instrumentation / Q000379:methods; D012825:Silicon
chemical_list: D007074:Immunoglobulin G; D007073:Immunoglobulin E; D012825:Silicon
keywords: IgE; IgG4; Immunologic tests; allergens and epitopes; clinical immunology; component-resolved diagnostics; food allergy; protein microarray