Age dependent type 1 diabetes pathogenesis

Ake Lernmark

FromJoerg Ermann &

C. Garrison Fathman Nature Immunology

2, 759 - 761 (2001)

Insulitis

Residual -cell function in newonset Type 1 diabetes

Age C-peptide level within normal range

(years) At diagnosis One year Two years

0-15 20% 10% <5%

15-34 60% 55% 46%

rhw 5/99

Type 1 diabetes genes

v HLA DQ2, DQ8, or both, represents almost 90% of all type 1 diabetes patients younger than 20 years of age. The risk of DQ2/8 heterozygotes decreases with increasing age.The protection of DQ6.2 is attenuated by increasing age and is lost at about 35 years of age.

vClass I - INS VNTR -short tandem repeats - increase the risk by about 2-5 %.

v CTLA-4 - long AT-repeats at the 5’ end UTR - increasethe risk by about 2-3%.

v

v

ENVIRONMENTAL FACTORS

VIRUS: MUMPS,COXSACKIE, RUBELLA, ECHO,ROTA, LJUNGAN AND OTHERS.

FOOD ITEMS: NITROSAMINES, MILK PROTEINS

* MONOZYGOTIC TWINS 20-30% CONCORDANCE.** ONLY 10-15% OF NEW PATIENTS HAVE A

PARENT OR SIBLING WITH THE DISEASE.

GESTATIONAL INFECTIONS AND ABO INCOMPATIBILITY

VIRUS AND TYPE 1 DIABETES

Coxsackie Human, mice (Yoon)Rubella Human, hamsterMumps HumanCytomegalovirus HumanRotavirus Human

CBV4 T cell activation (Vbeta analysis): T1DM=controls (Varela-Calvino et al. 2001)

CBV4 T cell proliferation: T1DM > controls (Juhela et al 2000)CBV4-specific T-cell epitopes: T1DM = controls

(Martilla et al. 2001)No or little cross reactivity between molecular mimicry regions

(Several authors)

ABO and hyperbilirubinemiaAutoantibody Controls ABO immunization Hyperbilirubinemia

IA-2Ab 1,4% (4/288) 6,6% (10/151)* 1,6% (5/311)

GAD65Ab 1,6% (5/320) 2,6% (4/151) 1,3% (4/311)

ICA 0,6% (2/320) 4,0% (6/151)** 4,2% (13/311)***

Difference compared to controls: * p=0.007; ** p=0.015; *** p=0.003.

All samples are cord blood.

Diagnostic sensitivity and specificityof autoantibodies for Type 1 diabetes

Autoantigen Sensitivity Specificity

Insulin 40-70% 99%

GAD65 70-80% 99%

IA-2 50-70% 99%

rhw12/98

GENETIC EFFECTS ON AGE-DEPENDENT ONSET AND ISLET CELL ANTIBODIES IN TYPE 1 DIABETES.

R

R

R

R

R

PATIENTS: INCIDENT, 0-34 YEARS OF AGE n=971

CONTROLS: MATCHED FOR AGE AND GENDERn=702

HLA, INS VNTR AND CTLA-4

GAD65A, IA-2A, IAA AND ICA

LOGISTIC REGRESSION TO MODEL THE NATURALLOGARITHM OF THE ODDS

0 10 20 30

B0 DQ8, Males

0.8

0.6

0.4

0.2

0 10 20 30

A0 DQ8, Females

0 DQ2

0 DQ2

Age at clinical onset (years)

0 10 20 30

B0 DQ8, Males

0.8

0.6

0.4

0.2

0 10 20 30

A0 DQ8, Females

0 DQ2

1 DQ2

0 DQ2

1 DQ2

Age at clinical onset (years)

0 10 20 30

B0 DQ8, Males

0.8

0.6

0.4

0.2

0 10 20 30

A0 DQ8, Females

0 DQ2

1 DQ2

2 DQ2

0 DQ2

1 DQ2

2 DQ2

Age at clinical onset (years)

RISK FOR TYPE 1 DIABETES AS FUNCTION

OF AGE, GENDER, HLA AND GAD65A. THE ODDS TO DEVELOP TYPE 1 DIABETES:

A FEMALE WITH GAD65Ab HAS 3 TIMES THE RISK OF A MALE.

COMPARED TO A FIVE YEAR OLD WITH GAD65Ab BUT NO DQ2: 3 TIMES HIGHER RISK WITH ONE DQ2 8 TIMES HIGHER RISK WITH TWO DQ2

DQ2 DOES NOT AFFECT THE RISK FOR A GAD65AB POSITIVE 34 YEAR OLD

0.8

0.6

0.4

0.2

0.00 10 20 30 0 10 20 30

A B0 DQ8, Females

0 DQ2 0 DQ2

0 DQ8, Males

Age at clinical onset (years)

0.8

0.6

0.4

0.2

0.00 10 20 30 0 10 20 30

A B0 DQ8, Females

0 DQ2

1

0 DQ2

1

0 DQ8, Males

Age at clinical onset (years)

0.8

0.6

0.4

0.2

0.00 10 20 30 0 10 20 30

A B0 DQ8, Females

0 DQ2

1

2

0 DQ2

1

2

0 DQ8, Males

Age at clinical onset (years)

RISK FOR TYPE 1 DIABETES AS FUNCTION OF AGE, GENDER, HLA, AND IA-2Ab.

THE ODDS FOR TYPE 1 DIABETES WITH IA-2AbAT 5 YEARS OF AGE IS 11 TIMES THAT AT34 YEARS OF AGE.

THE ODDS FOR EACH ADDITIONAL DQ8:1.5 TIMES FOR ONE DQ83.0 TIMES FOR TWO DQ8

THE ODDS OF EACH ADDITIONAL DQ2:DECREASES0.27 TIMES FOR ONE DQ20.6 TIMES FOR TWO DQ2

Insulin autoantibodies are associated with a combination of HLA-DQ8 and INS VNTR.

Click for larger picture

RISK FOR TYPE 1 DIABETES AS FUNCTION OF AGE, GENDER, HLA, INS VNTR AND IAA.

THE ODDS FOR TYPE 1 DIABETES WITH IAAAT 5 YEARS OF AGE IS 10 TIMES THAT AT34 YEARS OF AGE.

THE ODDS FOR EACH ADDITIONAL DQ8:1.4 TIMES FOR ONE DQ82.1 TIMES FOR TWO DQ8

THE ODDS OF EACH ADDITIONAL INS VNTRCLASS I ALLELE:

1.5 TIMES FOR ONE CLASS I2.2 TIMES FOR TWO CLASS I

SUMMARY, SO FAR……...

* MULTIPLE ENVIRONMENTAL FACTORS. *GESTATIONAL EFFECTS.

* HLA HAS THE MAJOR GENETIC EFFECT - INS VNTR AND OTHER GENETIC FACTORS CONTRIBUTE.

* AGE-DEPENDENT EFFECTS OF HLA AND ONGAD65AbIAA - INS VNTR CONTRIBUTESIA-2Ab

* USEFUL INFORMATION FOR PREDICTION?

COMBINATIONS OF ISLET CELL

AUTO-ANTIBODIES

PREDICT

TYPE 1 DIABETES

0

20

40

60

80

100

0 2 4 6 8 10

Years of follow-up

Three autoantibodies

Two autoantibodies

One autoantibody

Click for larger picture

WHAT ABOUT CHILDREN AND TEENAGERS?

* WASHINGTON PREDICTION STUDY:> 4 500 14 year olds were screenedFollow up 9 years.All 15 children developing diabetes were predicted. No false negatives.

No false positives. Hagopian et al. Diabetes Care 2002

* SCREENING NEWBORNS: HLA and antibodiesDIPP (Finland), TRIGR (international), DAISY (Denver, CO), PANDA (Gainesville, FL),ABIS (South East Sweden), DiPiS (South Sweden)MELBOURNE NEWBORN STUDY

TYPE 1 DIABETES IS A T-CELL MEDIATED DISEASE

* Poor antigen quality has hampered novel technologies to detect T-cells reactive with GAD65, proinsulin (PI), and IA-2.

* The second T cell IDS workshop reported GAD65 (Diamyd Medical) generated in insect cells that stimulate relevant clones and

does not inhibit third-party antigens.

* A PI preparation generated in bacteria was free of effects on proliferation to third-party antigens and low in endotoxin.

* These preparations should be useful to develop robust and sensitive assays of autoantigen-specific T cells that predict diseases.

* Peakman et al. Report of phase II of the Second International Immunology of Diabetes Society Workshop for Standardization of T-cell assays. Diabetes 50:1749-54, 2001.

GAD65Ab modulate GAD65 antigen presentation.

• T-cell hybridomas• DRB1*0401

restricted• GAD65 peptide

274-286 dependent• APC from

DRB1*0401 subjects• IL-2 release response

• GAD65Ab positive sera from new onset children at various end-point titers

Reijonen et al Diabetes 2001

GAD65Ab ENHANCE ANTIGENPRESENTATION

0 .0 2 .5 5 .0 7 .5 10 .0 12 .5

1306

853

898

826

613

708

652

686

591

673

622

IL -2 concentration (U /m l)

0.00 0.25 0 .50 0.75 1.00 1.25

1306

853

898

826

613

708

652

686

591

673

622

G A D 65 antibod y indexGAD65 antibody index

1,251,00,750,50,250,0IL-2 concentration(U/ml)

0,0 2,5 5,0 7,5 10,0 12,5

ANTIBODY-MEDIATED POTENTIATION OF ANTIGEN-PRESENTATION.

• GAD65Ab mediated potentiation of antigen presentation may explain:

• Preservation of conformation dependent GAD65Ab before diagnosis.

• Preservation of conformation dependent GAD65Ab after diagnosis when beta cells are gone.

• Acceleration of beta cell destruction by recruiting new CD4 and CD8 T cells.

SUMMARY AND CONCLUSIONS

* HLA HAS THE MAJOR EFFECT - OTHER GENETIC FACTORS SUCH AS INS VNTR AND CTLA-4 CONTRIBUTE.

* MULTIPLE ENVIRONMENTAL FACTORS. *GESTATIONAL EFFECTS.

*EARLY T CELL RESPONSES ARE KEY TO INITIATION OF BETA CELL AUTOIMMUNITY.

* AGE-DEPENDENT EFFECTS OF HLA AND ONGAD65AbIAA INS VNTR CONTRIBUTEIA-2Ab.

* CHRONIC BETA-CELL AUTOIMMUNITY MAY BE MAINTAINED BY AUTOANTIBODY-FACILITATED T CELL RESPONSES.

Acknowledgement

• CHRISTIANE HAMPE• LUO DONG• TERRI DANIELS• LISA HAMMERLE

• STEN-A. IVARSSON• CORRADO CILIO

• JINKO GRAHAM• NORMAN BRESLOW

• HELENA REIJONEN• GERALD T NEPOM

• SWEDISH DIABETES REGISTRIES FOR CHILDREN AND ADULTS