BDC Keystone Genetics Type 1 Diabetes www.barbaradaviscenter.org Immunology of diabetes book with Teaching Slides
PRACTICAL Trailnet screens relatives and new onset patients for autoantibodies and HLA when appropriate for free 1-800-halt-dm1 GAD Dynal commercial laboratory excellent assay re sensitivity BDC has laboratory re outside samples: liping.yu@ucdenver.edu (only ZnT8 at present and anti-interferon and HLA re DM) Book Immunology diabetes with slides www.barbaradaviscenter.org
893 newly diagnosed diabetic subjects (Age: 0.92 to 24.65 yrs) AutoAb to GAD65, ICA512bdc,insulin (IA-2ic, ICA, ZnT8) #4: ZnT8 antibodies: Beta Cell Zinc Transporter* 753 patients, >= 1 autoantibodies (84.3%) 140 patients, negative for all autoantibodies (15.7%) *ZnT8 Patent BDC
AB positive DM C-peptide (pg/ml) 6000 5500 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 0 2 4 6 8 10 12 14 Diabetes duration (years)
AB negative DM C-peptide (pg/ml) 6000.0 5500.0 5000.0 4500.0 4000.0 3500.0 3000.0 2500.0 2000.0 1500.0 1000.0 14.1 19.1 13.1 15.7,15 8.0 11.5 6.6 12,122 14.5 patient sister 17.2 2.9 3.3 22.9 14.3 11.8 8.2 500.0 0.0 0 2 4 6 8 10 12 14 Duration of diabetes (years)
JDRF npod 37 yo 20 yrs DM Ab- C-peptide=.2 Atkinson PI
Islets with Beta Cells
Pseudoatrophic islets
Monogenic IPEX syndrome Autoimmune Polyendocrine Type 1 Polygenic Autoimmune Polyendocrine Type 2 Type 1A diabetes
9 Months of Age
Mutation of FoxP3 gene - Controls regulatory T cells Approximately 80% of children with syndrome develop diabetes Bone marrow transplant can reverse
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
Eisenbarth GS, Gottlieb PA. NEJM 350:2068-79 2004
RISK OF TYPE 1 DM Proband with DM % Diabetes % Autoantibody+ General Population 0.3% 4% >=1 Antibody Offspring 1% 4.1% Sibling 6% 7.4% Dizygotic Twin 6% 10% Mother 2% 5% Father 4.6% 6.5% Both Parents 10%?? Monozygotic Twin 60% 70-80%
% Diabetes 100 90 80 70 60 50 40 30 20 10 Proband Diabetes Non-Proband Antibodies Non-Proband Diabetes 0 0 0 10 20 30 40 50 60 70 80 Age N = 83 100 90 80 70 60 50 40 30 20 10 % Antibody Positive Redondo, Jeffrey, Fain, Eisenbarth, Orban NEJM 359:2849 2008
6.50 2.25 2.00 1.75 1.50 1.25 1.00 HLA Insulin production & metabolism Locus Immunity β cell apoptosis protection Unknown function
The IDDM2 Locus Predisposing IDDM2 Class I VNTR 26-63 repeats 21 alleles Insulin Gene (INS) Protective IDDM2 Class III VNTR 140-200 repeats 15 alleles Insulin Gene (INS) VNTR = Variable Number of Tandem Repeats
Antigen Endocytosis APC MHC II CD4 + T cell T Cell Receptor Trimolecular Complex
The Major Histocompatibility Complex Human Chromosome 6 Class II Class III Class I DP DQ DR B C A Antigen Processing Genes Complement Proteins Cytokines Class I-like genes and pseduogenes Mouse Chromosome 17 Class III Class II Class I Class I K I-A I-E D L
Human Chromosome 6 Class II Class III Class I DP DQ DR B C A Allele: Haplotype: DRB1*0401 DRB1*0401 DQB1*0302 Genotype: DRB1*0401 DQB1*0302 DRB1*0301 DQB1*0201 Type 1 Diabetes: Molecular, Cellular and Clinical immunology http://www.uchsc.edu/misc/diabetes/eisenbook.html
HBDI Series: Transmission from Parents with second haplotype not DQ2 or DQ8 90 80 70 60 50 40 30 20 10 0 N= 406/333/33/ 79/ 72/ 55/ 55/ 44/ 42/ 38/ 29/ 37/ 4 DQ8 DQ2 0401/0402 0102/0502 0101/0501 0102/0604 03/0303 03/0301 0501/0301 0201/02 0103/0603 0102/0602 0101/0503(1401)
NEwborn Cohort (NEC) General population cohort (SOC) Sibling/Offspring Cohort screened = 33,096 Enrolled 391 high risk (2.4 %) 456 moderate risk 384 average-low risk 1,231 offspring 51 111 509 siblings 49 65 254 671 368 Total enrolled 2,270
Haplotype Sharing Siblings Share Both Haplotypes Family A Haplotypes A B Siblings Share One Haplotype Family B Siblings Share No Haplotypes Family C C D A B C D A B C D HLA-A 1 2 29 30 1 2 29 30 1 2 29 30 HLA-DRB1 3 3 4 4 3 3 4 4 3 3 4 4 Father Mother Father Mother Father Mother Diabetic Proband DAISY Sibling Diabetic Proband DAISY Sibling Diabetic Proband DAISY Sibling HLA-A 1 29 1 29 1 29 1 30 1 29 2 30 HLA-DRB1 3 4 3 4 3 4 3 4 3 4 3 4 A C A C A C A D A C B D
% Autoantibody Positive 100 Siblings at high risk 90 (Share 2) Siblings at low risk 80 (Share 0 or 1) N = 29 70 60 50 40 30 20 10 N = 19 0 0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 Age (y) % With Diabetes 100 90 80 70 60 50 40 30 20 10 0 0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 Age (y) Aly et al. PNAS 103:14074-9 2006
Autoantibody Positive (%) 30 High Risk 25 (no protective alleles) Low Risk (DRB1*0403 20 or DPB1*0402) 15 10 5 Diabetes (%) 0 0.0 2.5 5.0 7.5 10.0 12.5 Age (years) 30 High Risk 25 (no protective alleles) Low Risk (DRB1*0403 20 or DPB1*0402) 15 10 5 0 0.0 2.5 5.0 7.5 10.0 12.5 Age (years) Baschal et al. Diabetes 56:2405-9 2007
Transglutaminase autoantibodies (5% celiac disease) 21-Hydroxylase autoantibodies (1% positive: predictive Addison s disease) Sensitive TSH assay (hypothyroidism very common)
Spontaneous Animal Models BB rat Homozygosity Lymphopenia (Ch4;Ian) RT1-U U class II (Ch 20) Additional Loci (Ch2,18,X) NOD mouse Polygenic: class II + class I loci + IL-2 linked polymorphism + >12 iddm loci Long-EvansTokushima Rat RT1-U U MHC Homozygosity Chr 11-Cblb gene BDC
TCR MHC PEPTIDE INS B:9-23
AA Peptide Side Chains I-A g7 Peptide
H S L V 9 13 E A L 16 A Y L V C 23 G R E G Barbara Davis Center
% of Diabetes Free 100 80 60 40 20 ins1+, ins2- (n=24) B16:A Insulin ins1-, ins2- (n=31, P<0.0001) 0 0 10 20 30 40 50 60 Weeks Nakayama et al. Nature 435:220-3 2005
ARG(22) GLU GLY CYS VAL LEU TYR LEU ALA(14)
TCR MHC PEPTIDE INS B:9-23
Antigen Presenting Cell Peptide V V D J J Chr. 14 Chr. 6
THOUGHTS IMMUNE MEDIATED DIABETES HAS A NUMBER OF GENETIC CAUSES DEFINING NON-AUTOIMMUNE IMPORTANT HLA ALLELES MAJOR DETERMINANT IN TERMS OF DIAGNOSIS AND PREDICTION TRIALS IN EXTREME RISK PATIENTS PLANNED/UNDERWAY