Post on 30-Dec-2015
description
April 23, 2013
ISAC and Component-resolved Diagnosis
Douwe de Boer, Chris Nieuwhof, Judith Bons en Paul Menheere
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 2
Allergy: clinical relevance “in vitro” testing
Ebo et al., University of Antwerp
A
B
C
allergen = mixture of allergen components
Component-resolved Diagnosis (CRD)
intra-allergenic heterogeneity
ED
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 3
Multiplex assay: multiple analysis of specific
IgE directed against allergen components in one
single run
RAST
Single-analyte assay: single analysis of specific IgE directed against
single allergens, single allergen components or mixtures of allergens
classical ImmunoCAP assay
ISAC (Immuno Solid-phase Allergy Chip )
ImmunoCAP ISAC (16 spots per mm2)
ISAC112
40 µLRAST1
30 µL
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 4
intra-allergenic heterogeneity
non-specific Lipid Transfer Protein
Pathogenesis Related-10 protein
Profilin
Storage protein
Storage protein
Storage protein
Storage protein
Storage protein
Storage protein
Component-resolved Diagnosis (CRD)
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 5
Complications Detecting specific IgEs - 1
Ara h 9
Ara h 8
Ara h 5
non-specific Lipid Transfer Proteins
Pathogenesis Related-10 proteins
Profilins
inter-allergenic homogeneity
Pan-allergens
intra-allergenic heterogeneity
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 6
Complications Detecting specific IgEs - 2
intra-allergenic heterogeneity
inter-allergenic homogeneity
Component-resolved Diagnosis (CRD)
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 7
Pan-allergens – risks and severity
Cross-reactive CarbohydrateDeterminants
specific glycan epitope
initially CCD was considered to be important to explain cross-reactivity
mainly “plant” derived pan-allergens
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 8
Profilins
rMal d 4
rHev b 8
rPhl p 12rBet v 2rMer a 1 rAra h 5
rPru p 4
Cytoskeleton proteins
Highly conserved proteinsTrue pan-allergen
(high degree of cross-reactivity)
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 9
Pathogenesis Related-10 Protein (PR-10)
rMal d 1
rDau c 1
rPru p 1
rAra h 8rCor a 1.01 rCor a 1.04
rApi g 1
rGly m 4rBet v 1
rPru ar 1rPyr c 1
rPru av 1
Unknown function
Large family and conserved proteinsHeat and acid labile proteins
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 10
non-specific Lipid Transfer Protein (LTP)
rCor a 8rPru p 3
rAra h 9 rMal d 3
rZea m 4
rPru av 3
Relatively conserved proteinsHeat and acid stable protein
Shuttle protein of
lipids
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 11
Storage Protein
rBer e 1
rAra h 1rAra h 2rAra h 3
rAra h 6
rCor a 9
rSes i 3
nGly m 5nGly m 6
Proteins for storage of energy mainly in seedsRelatively less conserved proteins
pseudo-Pan-allergen (low degree of cross-reactivity)
“Voorraad of opslag eiwitten”
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 12
Pan-allergen sensitization in Europe
CRD and ISAC | De Boer, Nieuwhof, Bons and Menheere | April 23, 2013 13
ISAC and Component-resolved Diagnosis
Besides separate allergen components groups of pan- allergens can be distinguished
Conclusions and remarks
Components and pan-allergens are being associated with risks
Component-resolved Diagnosis can give insights in sensibilisations for separate allergen components
ISAC is a multiplex assay (an extensive number of components)
RAST is a single analyte assay (limited number of components)
inter-allergenic homogeneity
intra-allergenic heterogeneity