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Coeliac disease: pathogenesis Riccardo Troncone Department of Pediatrics & European Laboratory for the Investigation of Food-Induced Diseases University Federico II, Naples, Italy
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Coeliac disease: pathogenesis Riccardo Troncone - … · Coeliac disease: pathogenesis Riccardo Troncone ... • This means a longer activation of tyrosyne kinase receptors ... Protocol

May 30, 2018

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Page 1: Coeliac disease: pathogenesis Riccardo Troncone - … · Coeliac disease: pathogenesis Riccardo Troncone ... • This means a longer activation of tyrosyne kinase receptors ... Protocol

Coeliac disease:pathogenesis

Riccardo Troncone Department of Pediatrics & European Laboratory for the

Investigation of Food-Induced DiseasesUniversity Federico II, Naples, Italy

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Definition of Celiac Disease

CD is an immune-mediated systemic disorder elicited

by gluten and related prolamines in genetically

(mainly HLA) susceptible individuals, characterized

by the presence of variable combination of gluten-

dependent clinical manifestations, CD specific

antibodies, HLA DQ2 and DQ8 haplotypes and

enteropathy

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Genetics

Mechanisms

Prevention

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Risks for genotype groups in the population

Group Genotype DR Genotype group DQ Risk %

H1/H1 DR3/DR3 G1(Double DQ2)

21 %H1/H2 DR3/DR7

H2/H3 DR5/DR7G2

(DQ2 in trans)17 %

H1/H3 DR3/DR5

G3(DQ2 in cis)

6 %H1/H4 DR3/DR4

H1/H5 DR3/DRX*

H2/H2 DR7/DR7 G4(1/2 DQ2 and/or

DQ8)5 %H2/H4 DR7/DR4

H4/H4 DR4/DR4

H5 altri G5 0,6 %

Risk for an individual to develop the disease according to his genotype group

Bourgey M. et al. Gut 2007;56:1054-9

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Genetics of coeliac diseaseNon-HLA genes

- T-cell development in the thymus(THEMIS, RUNX3, TNFR SF14, ETS1)

- Immune detection of viral RNA (TLR7-8)

- T-B costimulation (CTLA4-ICOS-CD28, TNFR SF14, CD80, ICOS LG, TNFR SF9,

TNF SF4)

- Cytokine & chemokine receptors (2q11-12 ILR cluster (IL18 RAP), 3p21 chemokine (CCR5), 4q27

(IL2-21) , IL12A, TNFR SF18, CCR4)

- Non-identified pathways LPP

Dubois et al. Nat Genet 2010;42:295-302

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It is possible to establish a “risk profile”

Frequency distribution of non-HLA risk alleles in Cases and Controls

Romanos J. et al. Gastroenterology 2009;137:834-40

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Genetics

Mechanisms

Prevention

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Pathogenic mechanisms in celiac disease

Lamina propria

Gianfrani C. & Auricchio S.Prospettive in Pediatria 2008

Deamidated peptide

TG2

γ/δδδδ

APC

Q

E

IFN-g

Gliadin

TCRHLA-DQ2/8

T CD4+

CD4+ Tr1

IL-10TGFb

E

TCRHLA I-A 2

Macrophage/DC

IELCD94 HLA-E

IL-15

IFN-a

Innate responseAdaptive response

NKG2D

IL-15

CoX2↑↑↑↑CD83↑↑↑↑

CD25↑↑↑↑

MICA

31-4331-49 Virus

B Cell Anti-gliadin and

anti-TG2 Antibodies

Tyrosine-kinase receptors activation(EGF)

CD8

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Celiac disease: disease mechanisms

• Gliadin resistance to enzymatic digestion• Paracellular permeability alterations• Interference with endocytosis pathway • Activation of innate immunity mechanisms• Activation of lamina propria gliadin-

specific CD4+ (and CD8+) lymphocytes• Induction of autoantibodies (anti-

transglutaminase) and their pathogenetic role

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Gliadin resistance to enzymatic digestion

• Resistance to proteolysis by gastric, pancreatic and brush border enzymes due to high number of proline residues

• Polipeptides with high molecular weight (e.g. 33mer) final product of hydrolysis

• Efficacy of prolylendopeptidase of bacterial and fungal origin

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33mer (α2-gliadin 56-88)• Prodotto finale della digestione, resistente all’idrolisi a causa dell’elevato

contenuto in proline (13 su 33 residui)

• Contenente 6 copie parzialmente overlappanti di 3 epitopi T: potente stimolatore della risposta T

Khosla & Sollid, 2004

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Pathogenic mechanisms in celiac disease

Lamina propria

Gianfrani C. & Auricchio S.Prospettive in Pediatria 2008

Deamidated peptide

TG2

γ/δδδδ

APC

Q

E

IFN-g

Gliadin

TCRHLA-DQ2/8

T CD4+

CD4+ Tr1

IL-10TGFb

E

TCRHLA I-A 2

Macrophage/DC

IELCD94 HLA-E

IL-15

IFN-a

Innate responseAdaptive response

NKG2D

IL-15

CoX2↑↑↑↑CD83↑↑↑↑

CD25↑↑↑↑

MICA

31-4331-49 Virus

B Cell Anti-gliadin and

anti-TG2 Antibodies

Tyrosine-kinase receptors activation(EGF)

CD8

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Jabri B. et al. Nat Rev Immunol. 2009;9:858-70

Gliadin peptides and stress pathways

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P31-43 interferes with the endocytic

pathway

e.g. it delays EGFR in early endocytic vesicles increasing

trafficking of recycling endosomes

Possible model of P31-43 non T-cell mediated activity

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Interference of gliadin with endocytosis and its consequences

• Gliadin peptides interfere with endocytosis pathway delaying

maturation of vesicules from “early” to “late endosomes”

• This means a longer activation of tyrosyne kinase receptors (example

EGFR). The prolonged activation of EGFR causes on different

cellular and tissutal types (included small intestine mucosa) different

biological effects: rearrangement of actin and alterations of

permeability, proliferation and tissue remodeling, probably activation

of innate immunity (higher expression of IL15)

• It remains to be explained the higher susceptibility of celiac patients to

these biological activities of gliadin (on a genetic basis?)

Barone et al, Gut 2007

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Activation of innate immunity mechanisms

• Higher expression of IL15 at epithelial and lamina propria

levels in intestinal mucosa of celiac patients (induced by

p31-43)

• Higher epithelial infiltration of NK-like lymphocytes and

higher molecular expression (NKG2D) that facilitate

cytotoxicyty (induced by IL15)

• Higher MICA expression on intestinal epithelium (induced

by p31-43 and mediated by IL15). MICA is a target of

NK-like TCR independent cytotoxic cells

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Proinflammatory cytokines in CD

• αIFN

• IL15

• IL18

• γIFN

• IL17

• IL21

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Pathogenic mechanisms in celiac disease

Lamina propria

Gianfrani C. & Auricchio S.Prospettive in Pediatria 2008

Deamidated peptide

TG2

γ/δδδδ

APC

Q

E

IFN-g

Gliadin

TCRHLA-DQ2/8

T CD4+

CD4+ Tr1

IL-10TGFb

E

TCRHLA I-A 2

Macrophage/DC

IELCD94 HLA-E

IL-15

IFN-a

Innate responseAdaptive response

NKG2D

IL-15

CoX2↑↑↑↑CD83↑↑↑↑

CD25↑↑↑↑

MICA

31-4331-49 Virus

B Cell Anti-gliadin and

anti-TG2 Antibodies

Tyrosine-kinase receptors activation(EGF)

CD8

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Deamidation critical step for presentation of gliadin to T cells

Deamidation of glutamine residues in glutammic acid, by tissutal transglutaminase, is critical for peptide-molecule linkage HLA (HLADQ2 - DQ8)

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Patient

CD220201CD061204

CD171204CD280900

CD202006CD290306

CD230204CD090401

CD310504

CD410052

CD210205CD130406

CD410051

CD140102

ωωωω-glia gluten33-mer25-mer 18-mer17-merAG11 AG12 T65 13-mer glia-20 p(31-49) DQ2-γγγγ-I DQ2-γγγγ-II 14mer1 DQ2-γγγγ-III DQ2-γγγγ-IV DQ2-γγγγ-V 14mer2 DQ2-ωωωω-I glt-156 glt(19-39) glu-5

pos

pos

7/14 7/14 7/14 7/14 5/14 2/14 4/14 5/14 0/14 0/14 5/14 2/14 2/14 3/14 2/14 2/14 1/14 5/14 0/14 0/14 1/14

αααα-gliadins γγγγ-gliadins glutenin

Recognition pattern of gliadin immunogenic peptides

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We have identified a peptide, A-gliadin 123-132 (QLIPCMDVVL) which isspecifically recognized by HLA A2-restricted CD8+ T lymphocytes from coeliacpatients(Gianfrani et al J Immunol 2003; Mazzarella et al Gastroenterology 2008)

The extensive infiltration of CD8+ T lymphocytes in the intestinal mucosa is one of the hallmarks in CD

1:5 IEL:EC innormal mucosa

1:1 IEL:EC inCD mucosa

IELCD8 TCD8 T CD8 TCD8 T CD8 T

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medium pA2

pA2-induced CD25+ cells mainly localized under intestinal epithelium layer

Mazzarella et al Gastroenterology 2008

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Gliadin reactive Tr1 cells are present in celiac intestinal mucosa and are functional

�CD3+CD4+

�TCR α/βα/βα/βα/β+�B7 integrin+

�CD103neg

�CD45RO+

0

200

400

600

800

1000

1200

Tr1.7 Tr1.9

TCC

net

pg

/ml

IL-10

IL-4

TGF-βIL-2

γ-IFN

11.000 21000

Gianfrani C. et al J Immunol 2006

Stim

ulat

ion

inde

x

0

1

2

3

4

5

6

7

Th.6 (R)

Tr1.7 (S)

R + S R +R

70

1511

58

R:5x104

S:5x104

S:R 2:1

S:R 1:1

S:R 0.2:1

S:R 0.1:1

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Control mucosa Untreated mucosa

0

20

40

60

80

100

120

140

160

180 Untreated CD Treated CDControls

p<0.01

p<0.01

Fox

p3+

cel

ls/m

m2

lam

ina

prop

riaFoxp3+; CD4+

Foxp3 expression in celiac mucosa:

Mazzarella G. et al. submitted

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T-regulatory cells in CD

No defect in the presence of T-cell regulatory cells inCD mucosa

�Tr1 cells are present in CD mucosa and not in controls andsuppress the Th1 pathogenic T cells

�CD4+CD25+Foxp3+ are increased in CD mucosa might beto counteract the mucosal inflammation

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Genetics

Mechanisms

Prevention

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Prevention is possible?

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Breast feeding and coeliac diseaseMetaanalysis of observational studies

Akobeng et al, Arch Dis Child 2006; 91:39-43

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Early infant feeding practices and coeliac diseaseAge at gluten introduction

In a population at risk for CD (HLA-DR3 positive), early

exposition to gluten (before the 3rd month) or late

exposition (after the 7th month) are associated with a

significant increase in the production of antitissue

transglutaminase antibodies (Norris, JAMA 2005)

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Early infant feeding practices and coeliac diseaseAmount of gluten

• Sweden experienced a unique epidemic of celiac disease in

children <2 years of age. The epidemic was partly explained by

the increased proportion of infants introducing large amounts of

gluten after breast feeding was ended (Olsson, Pediatrics 2008)

• The practice of introducing abruptly high amount of gluten, often

without ongoing breast-feeding, might have contributed to the

unexpectedly high prevalence of 3% recently found in this cohort

(Myleus, JPGN 2009)

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Recommendations

• Breast feeding for at least 6 months

• Gradual introduction of gluten in the diet, not before the 4th month of life, possibly when the child is still breast fed

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And for those more at risk…

� Attribute the risk

�Active intervention?

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H1H1 H1H2 H1H3 H1H4 H1H5 H2H2 H2H3 H2H4 H2H5 H3H3 H3H4 H3H5 H4H4 H4H5 H5H5

H1H1 [8;29] [8;29] [8;29] [8;29] [8;29] [8;29]

H1H2 [7;29] [8;29] [7;29] [1;29] [7;29] [7;29] [7;29] [1;29] [8;24] [7;24] [1;24]

H1H3 [1;29] [1;29] [1;29] [1;29] [1;29] [1;29]

H1H4 [7;29] [1;29] [7;29] [1;29] [7;29] [1;29]

H1H5 [1;29] [1;29] [1;29] [1;29] [1;29]

H2H2 [7;24] [7;24] [1;24]

H2H3 [1;24] [1;24] [1;24] [1;24] [1;24] [1;24]

H2H4 [1;24] [1;24] [1;24]

H2H5 [1;24] [1;24] [1;24]

H3H3

H3H4

H3H5

H4H4

H4H5

H5H5

Risk evaluation based on parents’ genotype

Risk > 20%

15% < Risk < 20%

10% < Risk < 15%

1% < Risk < 10%

Risk < 1%

Risk for a proband’s brother according to DQ genotype of parents

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Which possible intervention

• Delay the age at gluten introduction

• Give small amounts of gluten during breast feeding

• ?? Introduce gluten together with immunomodulatory molecules

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Prevention of coeliac disease in at-risk babiesPREVENT-CD – 36383 – FP6

•••

•••

••

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ProtocolENROLLMENT

Families with at least one celiac member

BIRTH HLA type in umbilical cord blood

Positive HLA DQ2/DQ8 Negative HLA DQ2/DQ8

•Breast feeding•Intervention between 4th-6th month (100 mg gliadin/die)•Gradual gluten introduction after 6th month•Clinical and serologic controls every 3-6 months

Persistent positivity in serological tests

Clinical symptoms

INTESTINAL BIOPSY

Annual controls

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Frontiers in Coeliac Disease

• Genetics: Clue to pathogenesis

• Pathogenesis: Gluten and activation innate immunity

• Clinical spectrum: CD and gluten sensitivity

• Diagnosis: New protocols

• Therapy: Alternative to GFD

• Prevention: Identification of at risk subjects

and feeding pattern in the first

year of life

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University of Naples Federico IINaples

R Auricchio, S Auricchio, MV Barone, L Greco, M Maglio, F Paparo, D Zanzi

Istituto di Scienze dell’Alimentazione CNR Avellino

C Gianfrani, F Maurano, G Mazzarella, M Rossi