Type 1A DiabetesImmunology and Polyglandular

Syndromes

Textbook on web with Teaching Slides

www.barbaradaviscenter.org

Develop Insulin 1 and insulin 2 Knockouts with B16 alanine-insulin 2

Insulin 1-KO Insulin 2-KOB:16ala-tg

X X

Insulin 1 - B Chain : FVKQHLCGPHLVEALYLVCGERGFFYTPKS

Insulin 2 - B Chain : FVKQHLCGSHLVEALYLVCGERGFFYTPMS

Insulin 1 (-)

Insulin 2 (-)

B:16ala-insulin 2 (+)

Tyrosine (TAC)

Alanine (GCC)

Nakayama et al. Prime role for an insulin epitope in the development of type 1 diabetes in NOD mice. Nature 435:220, 2005

“Stages” in Development of Type1 Diabetes

Age (years)

Genetic Predisposition

Bet

a ce

ll m

ass

(?Precipitating Event)

Overtimmunologicabnormalities

Normal insulinrelease

Progressiveloss insulinrelease

Glucosenormal

Overtdiabetes

C-peptidepresent

NoC-peptide

Stage I: Genetics• Polygenic-common

HLA DR+DQ+ other MHCInsulin gene PTPN22-lyp?CTLA-4

• “Monogenic”-rare

APS-I: AIRE mutation

IPEX syndrome: FoxP3 mutation

The Major Histocompatibility ComplexHLA: Human Leukocyte Antigens

0 base pairs 1 million

1 million 4 million

DPB1DPA1

LMP2TAP1

LMP7

TAP2DQB1

DQA1DRB1

DRA

CYP 21B C4A HSP70

TNFB C E A

MICA

Class I Region

MHC Class II Region

Class III Region

Human Leukocyte Antigen

human MHC

cell-surface proteins

important in self vs. nonself distinction

present peptide antigens to T cells

CLASS I: A,B,C CLASS II: DR,DQ,DP

HLAJ. Noble

TERMINOLOGY

DRB1*02

DQB1*0302DRB1*0401

DRB1*0401

DRB1*0301

DQB1*0302

DRB1*0401

DQB1*02

Allele:

Haplotype:

Genotype

J. Noble

Autoimmune Polyendocrine Syndromes

• APS-II (Autoimmune Polyendocrine)• APS-I (AIRE mutation) • IPEX (XPID): (Scurfy Mutation) • Anti-insulin Receptor Abs + “Lupus”• Hirata (Anti-insulin Autoantibodies)• POEMS (Plasmacytoma,..)• Thymic Tumors + Autoimmunity• Congenital Rubella + DM +Thyroid

IPEX: Immunodysregulation, Polyendocrinopathy, Enteropathy, X-linked

• Other Names XPID: X-linked polyendocrinopathy, immune dysfunction and diarrhea

XLAAD: X-Linked Autoimmunity Allergic Dysregulation

• Foxp3 Gene Mutation

• Loss of Regulatory T Lymphocytes

• Bone Marrow Transplant with Chimera “Cures”

BDC

APS-I• Autoimmune Polyendocrine Syndrome

Type 1• Autosomal Recessive mutations AIRE

(Autoimmune Regulator) gene• Mucocutaneous Candidiasis/Addison’s

Disease/Hypoparathyroidism• 18% Type 1 Diabetes• “Transcription Factor” in Thymus

BDC

TCR

MHC + Peptide

Autoreactive thymocyte

Self-peptides from "peripheral"

antigens

Tolerization of autoreactive thymocyte

MODEL AIRE Role in Preventing Autoimmunity

Thymic MedullaryEpithelial Cells

AIRE

Mathis/Benoist

Comparison APS-I and APS-II APS-I APS-II

• Onset Infancy• Siblings

AIRE gene mutated• Not HLA Associated• Immunodeficiency

AsplenismMucocutaneous Candidiasis

• 18% Type 1 DM

• Older Onset• Multiple Generations• DR3/4 Associated• No Defined

Immunodeficiency• 20% Type 1 DM

BDC

A family of diseases occurring in families

Type 1A Diabetes

Celiac Disease

Addison’s Disease

Thyroid AutoimmunityBDC

21-Hydroxylase Autoantibodies

0.5

1

1.5

2

Levels of autoantibodies

Healthy Controls Negatives PositivesType I Diabetics

n= 241 n= 817 n= 13

Figure 2

KnownAddison's

Yu et al, JCEM, 1999

Prevalence of TGA by HLA-DR amongst patients with type 1 DM, relatives of DM patients and

general population

0%

5%

10%

15%

20%

25%

DR3+ DR3-

IDDMRelativesPopulation

Prevalence

HLA-DR

BDC

Transglutaminase Autoantibodies and Marsh score (Disease Severity)

0.0

.5

1.0

1.5

2.0

2.5

tTG titer

0 1 2 3Marsh score

Spearman correlation, r = 0.569 p < 0.003

Hoffenberg, J. Peds 137:356 2000

Stage II: Precipitating Event

Diabetes Autoimmunity Study in the YoungSibling/offspring cohortGeneral population cohort

enrolled = 293 high risk 72

429 moderate risk 220

347 average - low risk 401

1,069 All 693

relatives 1,491 1,007

screened = 21,713

Stage III: Autoimmunity

Cytoplasmic ICA kindly provided by the discoverer Franco Bottazzo

Major Autoantibody Targets

• GAD65 (glutamic acid decarboxylase)

• IA-2 (ICA512): Insulinoma Associated Protein

• Insulin

Insulin Autoantibodies

• Usually the first autoantibody to appear• Highest levels in youngest children

developing type 1A diabetes• Mature high-affinity immune responses to

(pro)insulin anticipate the autoimmune cascade that leads to type 1 diabetes. Achenbach et al, J.Clin Invest 2004, 114:589

Stage IV: Progressive Loss Function

Stage V: Overt Diabetes

3

4

5

6

7

0 2 4 6 8 10 12 14

Hb

A1

c (%

)

3

4

5

6

7

0 2 4 6 8 10 12 14

3

4

5

6

7

0 2 4 6 8 10 12 14

Hb

A1

c (%

)

3

4

5

6

7

8

0 2 4 6 8 10 12 14

3

4

5

6

7

0 2 4 6 8 10 12 14

Hb

A1

c (%

)

3

4

5

6

7

0 2 4 6 8 10 12 14

3

4

5

6

7

0 2 4 6 8 10 12 14

3

4

5

6

7

0 2 4 6 8 10 12 14

3

4

5

6

7

0 2 4 6 8 10 12 14

3

4

5

6

7

0 2 4 6 8 10 12 14

Age (years)

Hb

A1

c (%

)

3

4

5

6

7

0 2 4 6 8 10 12 14

3

4

5

6

7

0 2 4 6 8 10 12 14

Age (years)

3

4

5

6

7

0 2 4 6 8 10 12 14

Age (years)

3

4

5

6

7

0 2 4 6 8 10 12 14

Age (years)

Hb

A1

c (%

)

3

4

5

6

7

0 2 4 6 8 10 12 14

A

Blood glucose values inControl vs. Daisy children

DAISY Control-FH Control no FH0

200

400

600

800

1000

1200

1400

Blo

od

glu

cose

, m

d/d

L

Barker et al, Diabetes Care 27: 1399, 2004

We can predict Type 1 diabetes.

We can prevent the disorder in animal models.

We cannot yet safely prevent in man.

NEXT

1. Improved T Cell Assays

2. Trials of antigen-specific therapies prior to autoantibodies.

3. Immunomodulator/Immunosuppressive Trials post-onset and with islet transplantation.

TRIALNET1-800-HALT-DM1

• Dalizumab+ MMF – New Onset Trial

• Oral Insulin Trial – Post Autoantibodies – Relative Screening

• With ITN: Anti-CD3 Trial Multiple course

• JDRF: Oral Insulin Prior to Anti-islet Autoantibodies being planned

Diabetes Autoimmunity Study in the Young (DAISY)

Also: Lars Stene, Patricia Graves, Heather Stanley, Jaime Keen, Peter Chase Carolyn Fronczak, Jennifer Barker, Akane Ide, Andrea Steck