1. ISAC and Component-resolved Diagnosis
April 23, 2013
ISAC and Component-resolved Diagnosis
Douwe de Boer, Chris Nieuwhof, Judith Bons en Paul Menheere

2. Ebo et al., University of Antwerp
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Allergy: clinical relevance  “in vitro” testing
intra-allergenic heterogeneity
allergen = mixture of allergen components
Ebo et al., University of Antwerp
Component-resolved Diagnosis (CRD) B A E C D

3. ISAC (Immuno Solid-phase Allergy Chip )
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
RAST
Single-analyte assay: single analysis of specific IgE directed against single allergens, single allergen components or mixtures of allergens
classical ImmunoCAP assay
RAST1
40 µL
ISAC (Immuno Solid-phase Allergy Chip )
ImmunoCAP ISAC (16 spots per mm2)
Multiplex assay: multiple analysis of specific
IgE directed against allergen components in one
single run
ISAC112
30 µL

4. Component-resolved Diagnosis (CRD)
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Storage protein
Storage protein
intra-allergenic heterogeneity
Storage protein
Storage protein
Profilin
Storage protein
Storage protein
Pathogenesis Related-10 protein
non-specific Lipid Transfer Protein
Component-resolved Diagnosis (CRD)

5. Complications Detecting specific IgEs - 1
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Complications Detecting specific IgEs - 1
intra-allergenic heterogeneity
inter-allergenic homogeneity
non-specific Lipid Transfer Proteins
Ara h 9
Pathogenesis Related-10 proteins
Ara h 8
Profilins
Ara h 5
Pan-allergens

6. Component-resolved Diagnosis (CRD)
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Complications Detecting specific IgEs - 2
Component-resolved Diagnosis (CRD)
intra-allergenic heterogeneity
inter-allergenic homogeneity

7. Pan-allergens – risks and severity
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Pan-allergens – risks and severity
initially CCD was considered to be important to explain cross-reactivity
mainly “plant” derived pan-allergens
Cross-reactive Carbohydrate
Determinants
specific glycan epitope

8. Profilins Cytoskeleton proteins Highly conserved proteins
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Profilins
Cytoskeleton proteins
Highly conserved proteins
True pan-allergen
(high degree of cross-reactivity)
rMal d 4
rHev b 8
rPhl p 12
rBet v 2
rMer a 1
rAra h 5
rPru p 4

9. Pathogenesis Related-10 Protein (PR-10)
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Pathogenesis Related-10 Protein (PR-10)
Large family and conserved proteins
Heat and acid labile proteins
Unknown function
rMal d 1
rDau c 1
rPru p 1
rAra h 8
rCor a rCor a 1.04
rApi g 1
rGly m 4
rBet v 1
rPru ar 1
rPyr c 1
rPru av 1

10. non-specific Lipid Transfer Protein (LTP)
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
non-specific Lipid Transfer Protein (LTP)
Relatively conserved proteins
Heat and acid stable protein
Shuttle protein of lipids
rCor a 8
rPru p 3
rAra h 9
rMal d 3
rZea m 4
rPru av 3

11. Storage Protein Proteins for storage of energy mainly in seeds
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Storage Protein
Proteins for storage of energy mainly in seeds
Relatively less conserved proteins
pseudo-Pan-allergen (low degree of cross-reactivity)
“Voorraad of opslag eiwitten”
rBer e 1
rAra h 1
rAra h 2
rAra h 3
rAra h 6
rCor a 9
rSes i 3
nGly m 5
nGly m 6

12. Pan-allergen sensitization in Europe
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
Pan-allergen sensitization in Europe

13. ISAC and Component-resolved Diagnosis
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013
ISAC and Component-resolved Diagnosis
Conclusions and remarks
Component-resolved Diagnosis can give insights in
sensibilisations for separate allergen components
intra-allergenic heterogeneity
Besides separate allergen components groups of pan-
allergens can be distinguished
inter-allergenic homogeneity
 Components and pan-allergens are being associated with risks
 ISAC is a multiplex assay (an extensive number of components)
 RAST is a single analyte assay (limited number of components)