Age dependent type 1 diabetes pathogenesis Ake Lernmark

From Joerg Ermann & C. Garrison Fathman Nature Immunology 2, 759 - 761 (2001)

Insulitis

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. v v v Class I - INS VNTR -short tandem repeats - increase the risk by about 2-5 %. v CTLA-4 - long AT-repeats at the 5’ end UTR - increase the risk by about 2-3%.

ENVIRONMENTAL FACTORS * MONOZYGOTIC TWINS 20-30% CONCORDANCE. ** ONLY 10-15% OF NEW PATIENTS HAVE A PARENT OR SIBLING WITH THE DISEASE. VIRUS: MUMPS,COXSACKIE, RUBELLA, ECHO, ROTA, LJUNGAN AND OTHERS. FOOD ITEMS: NITROSAMINES, MILK PROTEINS GESTATIONAL INFECTIONS AND ABO INCOMPATIBILITY

VIRUS AND TYPE 1 DIABETES Coxsackie Human, mice (Yoon) Rubella Human, hamster Mumps Human Cytomegalovirus Human Rotavirus 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 hyperbilirubinemia Autoantibody 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.

R R R R R GENETIC EFFECTS ON AGE-DEPENDENT ONSET AND ISLET CELL ANTIBODIES IN TYPE 1 DIABETES. R PATIENTS: INCIDENT, 0-34 YEARS OF AGE n=971 R CONTROLS: MATCHED FOR AGE AND GENDER n=702 R HLA, INS VNTR AND CTLA-4 R GAD65A, IA-2A, IAA AND ICA LOGISTIC REGRESSION TO MODEL THE NATURAL LOGARITHM OF THE ODDS R

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

RISK FOR TYPE 1 DIABETES AS FUNCTION OF AGE, GENDER, HLA, AND IA-2Ab. THE ODDS FOR TYPE 1 DIABETES WITH IA-2Ab AT 5 YEARS OF AGE IS 11 TIMES THAT AT 34 YEARS OF AGE. THE ODDS FOR EACH ADDITIONAL DQ8: 1.5 TIMES FOR ONE DQ8 3.0 TIMES FOR TWO DQ8 THE ODDS OF EACH ADDITIONAL DQ2: DECREASES 0.27 TIMES FOR ONE DQ2 0.6 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 IAA AT 5 YEARS OF AGE IS 10 TIMES THAT AT 34 YEARS OF AGE. THE ODDS FOR EACH ADDITIONAL DQ8: 1.4 TIMES FOR ONE DQ8 2.1 TIMES FOR TWO DQ8 THE ODDS OF EACH ADDITIONAL INS VNTR CLASS I ALLELE: 1.5 TIMES FOR ONE CLASS I 2.2 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 ON GAD65Ab IAA - INS VNTR CONTRIBUTES IA-2Ab * USEFUL INFORMATION FOR PREDICTION?

COMBINATIONS OF ISLET CELL AUTO-ANTIBODIES PREDICT TYPE 1 DIABETES Click for larger picture

WHAT ABOUT CHILDREN AND TEENAGERS? * WASHINGTON PREDICTION STUDY: > 4 500 14 year olds were screened Follow 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 antibodies DIPP (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

IL-2 concentration(U/ml) 0,0 2,5 5,0 7,5 10,0 12,5 0,0 0,25 0,5 0,75 1,0 1,25 IL-2 concentration(U/ml) GAD65 antibody index

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 ON GAD65Ab IAA INS VNTR CONTRIBUTE IA-2Ab. * CHRONIC BETA-CELL AUTOIMMUNITY MAY BE MAINTAINED BY AUTOANTIBODY-FACILITATED T CELL RESPONSES.

Acknowledgement JINKO GRAHAM NORMAN BRESLOW CHRISTIANE HAMPE LUO DONG HELENA REIJONEN GERALD T NEPOM SWEDISH DIABETES REGISTRIES FOR CHILDREN AND ADULTS CHRISTIANE HAMPE LUO DONG TERRI DANIELS LISA HAMMERLE STEN-A. IVARSSON CORRADO CILIO