MHC Class I Chain-Related Gene-A Is Associated with IA2 and IAA but Not GAD in Swedish Type 1 Diabetes Mellitus

MHC Class I Chain-Related Gene-AIs Associated with IA2 and IAAbut Not GAD in Swedish Type 1Diabetes Mellitus

MANU GUPTA,a JINKO GRAHAM,b BRIAN MCNEENY,b MARIANZARGHAMI,c MONA LANDIN-OLSSON,d WILLIAM A. HAGOPIAN,e

JERRY PALMER,d AKE LERNMARK,c AND CARANI B. SANJEEVIa

aDepartment of Molecular Medicine, Karolinska Institutet, S-17176 Stockholm,SwedenbDepartment of Statistics and Actuarial Science, Simon Fraser University,Burnaby V5A 1S6, CanadacDepartment of Medicine, University of Washington, Seattle 98195-7710,WashingtondDepartment of Medicine, University of Lund, Lund 98108, SwedenePacific Northwest Research Institute, Seattle 98195, Washington

ABSTRACT: In type 1 diabetes mellitus (T1DM), the frequency of anti-bodies against insulin (IAA), glutamic acid decarboxylase-65 (GAD65),ICA512/IA2 (IA2), and islet cell antigens (ICA) vary with human leuko-cyte antigen (HLA) composition of the patient. IAA, IA2 autoantibodies,and ICA are increased in DQ8 positives; GAD65 antibodies are increasedin DQ2 positives. MHC class I chain-related gene-A (MICA) is anothergenetic marker that has been proposed to be associated with T1DM.In this article, we looked at microsatellite polymorphism of MICA andits association with autoantibodies (IAA, IA2, and GAD65) in SwedishT1DM patients and if the association explains its importance in earlyevents in autoimmune response. We studied 635 T1DM patients between0–35 years. Frequency of MICA5/5 was positively associated with theformation of IAA and IA2 antibodies considered individually or in com-bination (odds ratio [OR], 95% CI, Pc: [IAA+ versus IAA–] : 4.94,2.09–11.62, <0.0005; [IA2+ versus IA2–] : 2.65, 1.52–4.59, 0.0015; [IAAand/or IA2+ versus rest]: 9.83, 2.37–40.78, <0.0015; [IAA and IA2+versus rest]: 3.51, 2.01–6.15, <0.0015). Also, –5.1/5.1 was increased inIAA+ patients compared to IAA– patients (2.82, 1.64–4.83, <0.0005).All patients positive for –5/5 developed at least one of the three antibodies.

Address for correspondence: Dr. C.B. Sanjeevi, Karolinska Institute, Department of MolecularMedicine, Karolinska Hospital Campus, CMM; L5:01, S-17176, Stockholm, Sweden. Voice: +46-8-51776254; fax: +46-8-51776179.

e-mail: [email protected]

Ann. N.Y. Acad. Sci. 1079: 229–239 (2006). C© 2006 New York Academy of Sciences.doi: 10.1196/annals.1375.036

229

230 ANNALS NEW YORK ACADEMY OF SCIENCES

Frequency of MICA5.1 was decreased in IAA+ (0.54, 0.36–0.81, 0.017),in IA2A+ (0.63, 0.45–0.88, 0.04), in IAA and/or IA2A+ (0.52, 0.33–0.84, 0.044), and in IAA and IA2A+ (0.55, 0.39–0.78, 0.0055) patientswhen compared with patients negative for corresponding antibodies. Fre-quency of MICA9, 5/5.1, and 5.1/9 was decreased in IAA+ compared toIAA– patients (0.51, 0.32–0.79, 0.021; 0.22, 0.11–0.44, <0.005; and 0.39,0.22–0.69, 0.026, respectively). Frequency of MICA9 and –5.1/9 was alsodecreased in IAA and/or IA2 antibody-positive patients while MICA5/5.1decreased in patients positive for IAA and IA2 antibody both together.IAA and IA2 antibodies are believed to appear early during the autoim-mune reaction against beta cells. Thus, according to our data, MICA–5/5and –5.1/5.1 is associated with early autoimmunity in T1DM patients.Our study suggests that MICA gene polymorphism is associated withautoantibody formation and that the polymorphism especially MICA5/5and –5.1/5.1 are important in early events of autoimmune reaction.

KEYWORDS: T1DM; MICA; GAD65; IA2; IAA

INTRODUCTION

Type 1 diabetes (T1DM) is an autoimmune disease marked by infiltra-tion of mononuclear cells into the pancreatic islets.1 Autoantibodies that de-velop against islet antigens like insulin (IAA), glutamic acid decarboxylase-65(GAD65), ICA512/IA2 (IA2), and islet cell antibodies (ICAs) are the markersfor the disease.2,3 ICAs, the traditional marker of T1DM can be detected inaround 70–90% of T1DM at and prior to disease onset and between 0% and5% healthy control subjects. ICAs have multiple and variable target moleculesincluding GAD65 and IA2.3,4 In majority of the T1DM cases, immune reactionagainst islet antigens and consequent formation of autoantibodies begins muchbefore the disease is diagnosed clinically.5–7 Retrospective studies have shownthat >90% of T1DM patients are positive for either antibody at diagnosis.8

For this reason, autoantibody markers have been used as markers for screeningprograms.3

Human leukocyte antigen (HLA) class II molecules-DQ and -DR are knownto be the genetic markers of T1DM.9 DR3-DQA1∗0501-DQB1∗0201 (DR3-DQ2) and DR4-DQA1∗0301-DQB1∗0302 (DR4-DQ8) are positively associ-ated with the disease and DR15-DQA1∗0102-DQB1∗0602 (DR15-DQ6) isnegatively associated with the disease in Swedish Caucasians.10

It has been reported that frequency of immune markers, such as IAA, GAD65autoantibodies, IA2 autoantibodies, and ICA varies with age at clinical onset,gender, and HLA composition of the patients.11–13 In Swedish T1DM, IAA,IA2 autoantibodies, and ICA are increased in DQ8 positives and are inverselyrelated to age-at-onset; GAD65 autoantibodies are increased in DQ2 positivesand are positively associated with age-at-onset; GAD65 autoantibodies andICA are increased in females while IA2 autoantibodies are increased in malepatients.11

GUPTA et al.: MICA AND AUTOANTIBODIES IN SWEDISH T1DM 231

Among many other genes, besides HLA class II, which have been linkedwith T1DM, one is MHC class I chain-related gene-A (MICA).14–16 MICA isa member of MIC family that consists of five genes: MICA, -B, -C, -D and-E. Of these, MIC-C, MIC-D, and MIC-E are pseudogenes while MICA andMIC-B are functional genes. MICA gene is located telomeric to the tumornecrosis factor (TNF-a) gene between the B-associated transcript (BAT-1) andthe HLA-B genes. MICA gene codes for MHC class I-like molecules with threedistinct extracellular domains (a 1, 2, and 3), a transmembrane (TM) segment,and a cytoplasmic tail, each coded by a separate exon. Unlike classical class Imolecules, MICA lacks association with b2-microglobulin.17

Sequence analysis of exon 5 (which codes the TM region of the protein) ofMICA gene has revealed trinucleotide repeat (GCT) polymorphism.18 So far, 5alleles of the exon 5 of the MICA gene, which consist of 4, 5, 6, or 9 repetitionsof GCT, or 5 repetitions of GCT with an additional insertion of G (GGCT) havebeen identified.18 These alleles have accordingly been named A4, A5, A6, A9,and A5.1. Also, MICA carries numerous nonsynonymous polymorphisms inthe sequence encoding extracellular region in the a-2 domain.19,20

MICA molecules are stress induced and their expression has been recognizedon intestinal epithelium and epithelial tumors. MICA molecules act as ligandsfor an activating receptor NKG2D on NK cells, gd T-cells, and CD8ab-Tcells.17,21 MICA molecules can be expressed on cell surface under stress con-ditions, for example, viral infection.21 Recently, NK cells have been shown tocontribute to beta cell destruction after CBV4 infection in NOD mice with per-turbed interferon signaling in beta cells.22 Though little is known about the roleof MICA in autoimmunity, based on the above facts, we speculate that certainenvironmental factors, for example, viruses can act as inducers of MICA in theislets and that activation of NKG2D receptor bearing NK cells or ab-T cellsthrough MICA may be one of the mechanism of initiation of T1DM patho-genesis. In this regard, microsatellite polymorphism in MICA gene TM regionhas been shown to be associated with T1DM in various populations.14–16,23–26

If MICA has a role in autoimmune response to b cell antigens, which even-tually leads to formation of autoantibodies to insulin, GAD65, IA2, and ICA,we speculate that the polymorphism of MICA gene might be associated withthe presence of autoantibodies. In this article, we looked if the microsatellitepolymorphism of MICA is associated with autoantibody formation and if theassociation explains its importance in early events in autoimmune response.

SUBJECTS AND METHODS

The present analysis is based on data from two population-based matchedcase–control studies described elsewhere.10 Patients received diagnoses andclassifications according to the World Health Organization (WHO) criteria. Inthe first study, all incident patients with T1DM who were younger than 15 years


and received a diagnosis anywhere in Sweden between September 1, 1986 andDecember 31, 1987 were asked to participate. Matched control subjects wereselected as described.27 The second study comprised incident patients withdiabetes who were 15- to 34-years old and received their diagnosis anywherein Sweden between January 1, 1987 and December 31, 1988; matched con-trol patients were also ascertained.28 The protocol for patient registration andsampling was the same regardless of age. The two studies administered overoverlapping years included a total of 971 incident patients with T1DM and 702control subjects. Of these, DNA samples from 670 patients (male = 397 andfemale = 273) and 534 healthy controls (male = 274 and female = 260) wereavailable for MICA typing. The current report is based on data from patientsalone. The study was approved by the ethics committee of Karolinska Institute,Stockholm, Sweden and informed consent was obtained from all participatingpatients and controls.

METHODS

Genetic Markers

MICA Genotyping

MICA alleles were determined using a fluorescence-based automated frag-ment size analysis. The TM region of the MICA gene (exon 5) was amplified bypolymerase chain reaction (PCR) using 5′-CCTTTTTTTCAGGGAAAGTGC-3′ as the forward primer and 5′-CCTTACCATCTCCAGAAACTGC-3′ as thereverse primer.18 The reverse primer was labeled at the 5′ end with the flu-orescent reagent HEX or 6-FAM (Pharmacia Biotech, Bjorkgatan, Sweden).The 12.5-mL PCR containing 20 ng of genomic DNA was carried out in aprogrammable thermal controller (PTC-100; MJ Research, Inc., Oldendorf,Germany). Following amplification, the numbers of GCT trinucleotide repeatunits were determined using Perkin-Elmer ABI 373 DNA sequencer (Perkin-Elmer, Norwalk, CT) and output file was analyzed with Genescan and Geno-typer softwares (Perkin-Elmer). MICA genotyping for the exon 5 microsatellitepolymorphism was successfully determined for 635 of 670 diabetic patients.

HLA Typing

HLA typing of DQA1 and DQB1 was carried out by PCR amplification of thesecond exon of the genes followed by dot blot hybridizations using sequence-specific oligo probes and by restriction fragment length polymorphism for DRtyping.29,30 Results for these have already been published.10,11,29 The numberof individuals for whom both MICA and HLA-DR were available were 601patients.


Immune Markers

Insulin Antibodies

IAA measured by radiobinding assay using acid–charcoal extraction andcold insulin displacement have been described elsewhere.31,32 IAA measure-ments were available on 557 patients.

Glutamate Decarboxylase Autoantibodies

For 0–15 years, antibodies to radiolabeled human Mr 65,000 GAD65 werequantified by immunoprecipitation assay using fluorographic densitometryas described earlier.33,34 For 15- to 35-year olds, GAD65 were radiolabeledby coupled in vitro transcription and translation, as described.35 Positive andnegative control sera were included in each assay and the antibody levels wereexpressed as an index defined as (cpm in unknown sample-negative control) /(positive control–negative control). GAD65 autoantibody index measurementswere available on 618 patients.

IA2 or ICA512

Antibodies to ICA512/IA2 were measured by radiobinding immunoassay.36

The 3′ portion of the ICA512cDNA: residues 602–979 (corresponding to thecytoplasmic portion of the protein) was amplified by RT-PCR from humanHTB-14 glioblastoma cells.37 In vitro translation with35S-methionine yieldeda polypeptide of 46 kDa highly precipitable by diabetic sera. Radiobindingassays used scintillation counting of protein A-Sepharose pellets. The levelsof IA2 were expressed as index calculated with the same formula as used forGAD65 radioassay. The results for IA2 were available for 615 patients.

Statistical Analysis

The odds ratio (OR) was calculated as described previously.38,39 Differencesin allele or genotype frequencies between the antibody-positive diabetics andthe antibody-negative diabetics were tested by the x2 method. Yates’ correc-tion or the Fisher’s exact tests were used when necessary. The P values werecorrected (Pc) for the number of comparisons, according to the number ofalleles or genotypes observed among diabetic subjects (5 for MICA alleles; 15for MICA genotypes, and 52 for MICA–HLA haplotypes). A Pc < 0.05 wasconsidered significant.


RESULTS

MICA and Single Antibody

IAA

Frequency of MICA –5/5 and –5.1/5.1 were significantly increased in IAA-positive group compared to IAA-negative group (OR, 95% confidence in-terval [CI], Pc: 4.94, 2.09–11.62, <0.0005 and 2.82, 1.64–4.83, <0.0005,respectively). Among alleles, frequency of MICA5.1 and MICA9 (OR, 95%CI, Pc: 0.54, 0.36–0.81, 0.017 and 0.51, 0.32–0.79, 0.021, respectively) andamong genotypes frequency of MICA5/5.1 and –5.1/9 were significantly de-creased in IAA-positive patients compared to IAA-negative patients (OR, 95%CI, Pc: 0.22, 0.11–0.44, <0.005 and 0.39, 0.22–0.69, 0.026, respectively)(TABLE 1).

IA2 Autoantibodies

Frequency of MICA5/5 was significantly increased (OR, 95% CI, Pc:2.65, 1.52–4.59, 0.0015) and MICA5.1 (OR, 95% CI, Pc: 0.63, 0.45–0.88,0.04) was decreased in IA2 autoantibody-positive patients compared to IA2autoantibody-negative patients (TABLE 1). We did not observe any signifi-

TABLE 1. Frequency of MICA alleles and genotypes in T1DM patients between 0 and35 years of age positive for IAA and those positive for IA2A versus those negative forcorresponding autoantibodies

IAA+ IAA− IA2+ IA2−n = 408 % n = 149 % n = 372 % n = 243 %

MICA5 149 36.52 57 38.26 151 40.59 81 33.33MICA5.1 221 54.17 102 68.45a 201 54.03 158 65.02g

MICA6 63 15.44 37 24.83 59 15.86 51 20.99

MICA9 62 15.20 39 26.17b 63 16.94 56 23.05

MICA5/5 70 17.16 6 4.02c 65 17.47 18 7.40h

MICA5/5.1 16 3.92 23 15.43d 28 7.53 20 8.23MICA5.1/5.1 114 27.94 18 12.08e 84 22.58 49 20.16

MICA5.1/9 30 7.35 25 16.78f 30 8.06 36 14.81

a = 0.54, 0.36–0.81, 0.017.b = 0.51, 0.32–0.79, 0.021.c = 4.94, 2.09–11.62, <0.0005.d = 0.22, 0.11–0.44, <0.005.e = 2.82, 1.64–4.83, <0.0005.f = 0.39, 0.22–0.69, 0.026.g = 0.63, 0.45–0.88, 0.04.h = 2.65, 1.52–4.59, 0.0015.


cant differences in frequencies of other MICA alleles or genotypes in IA2autoantibody-positive compared to -negative patients.

GAD65 Autoantibodies

None of the alleles or genotypes of MICA were associated with the presenceor absence of GAD65 autoantibodies (data not shown).

MICA and Two Antibodies

IAA/IA2 Autoantibodies

When patients positive for either IAA or IA2 autoantibodies were comparedwith those negative for both antibodies, frequency of MICA–5/5 was increased(OR, 95% CI, Pc: 9.83, 2.37–40.78, <0.0015) while that of MICA –5.1 and –9as well as –5.1/9 were decreased in those with antibody positivity (OR, 95%CI, Pc: 0.52, 0.33–0.84, 0.044; 0.48, 0.29–0.80, 0.032 and 0.35, 0.19–0.65,0.02, respectively) (TABLE 2).

When patients positive for both IAA and IA2 autoantibodies were comparedwith those negative for either or both the antibodies, frequency of MICA5/5 wasincreased (OR, 95% CI, Pc: 3.51, 2.01–6.15, <0.0015) while that of MICA5.1and –5/5.1 was decreased in those with antibody positivity (OR, 95% CI, Pc:0.55, 0.39–0.78, 0.0055 and 0.34, 0.16–0.69, 0.037, respectively) (TABLE 2).

GAD65/IA2 Autoantibodies

When patients positive for either GAD65 autoantibodies or IA2 autoanti-bodies were compared with those negative for both antibodies or when patientspositive for both GAD65 autoantibodies and IA2 autoantibodies were com-pared with those negative for either or both the antibodies, frequencies of noneof the alleles or genotypes of MICA differed significantly in any group (datanot shown).

MICA and Three Antibodies

All patients with any of the three antibodies were positive for MICA5/5 andnone of the patients with zero antibodies was positive for MICA5/5. MICA6was decreased in the group carrying any of the three antibodies (OR, 95% CI,Pc: 0.26, 0.12–0.56, 0.0045) or in group with all three antibodies (OR, 95% CI,Pc: 0.21, 0.09–0.49, 0.0025) when compared to the group with no antibodies(data not shown).


MICA and HLA Together and Autoantibodies

In all the stratifications done above according to the presence or absenceof one or two antibodies, we also analyzed MICA alleles (5, 5.1, 6) togetherwith DR3, with DR4 and with DR3-DR4 (heterozygous). We did not find anydifference in frequencies of MICA–HLA combinations when stratified for thepresence or absence of autoantibodies.

DISCUSSION

MICA is Associated with Autoantibody Formation

In our study, MICA5/5 was associated with the formation of both IAA andIA2 antibodies considered either individually or together. MICA5.1/5.1 wasalso associated with the formation of IAA alone. MICA5.1 was negativelyassociated with the formation of either IAA or IA2 antibodies considered

TABLE 2. Frequency of MICA alleles and genotypes in T1DM patients (0–35 years) pos-itive for IAA or IA2 versus those negative for both autoantibodies (2a); positive for bothIAA and IA2 versus those negative for either autoantibody

IAA or IA2+ IAA or IA2−N = 439 % N = 99 %

MICA5 170 38.72 33 33.33MICA5.1 240 54.67 69 69.69a

MICA6 71 16.17 24 24.24

MICA9 70 15.95 28 28.28b

MICA5/5 74 16.86 2 2.02c

MICA5/5.1 28 6.38 11 11.11MICA5.1/5.1 110 25.06 16 16.16

MICA5.1/9 34 7.70 19 19.2d

IAA & IA2+ IAA & IA2−N = 279 % N = 259 %

MICA5 110 39.43 93 35.91MICA5.1 141 50.54 168 64.86e

MICA6 38 13.62 57 22.01MICA9 41 14.70 57 22.01

MICA5/5 58 20.79 18 6.94f

MICA5/5.1 11 3.94 28 10.81g

MICA5.1/5.1 76 27.24 50 19.31MICA5.1/9 18 6.45 35 13.51

a = 0.52, 0.33–0.84, 0.044.b = 0.48, 0.29–0.80, 0.032.c = 9.83, 2.37–40.78, <0.0015.d = 0.35, 0.19–0.65, 0.020.e = 0.55, 0.39–0.78, 0.0055.f = 3.51, 2.01–6.15, <0.0015.g = 0.34, 0.16–0.69, 0.037.


individually or in combination. MICA–9 and –5.1/9 were negatively associatedwith IAA and with IAA and/or IA2 antibody formation while MICA–5/5.1 wasnegatively associated with IAA formation and with formation of both IAAand IA2 antibodies together. We did not find polymorphism in MICA geneto be associated either with GAD65 antibody formation or ICA formation.The present study, to our knowledge, is the first one to show the associationbetween MICA gene polymorphism and autoantibody formation in T1DM.

MICA is Important in Early Events During Autoimmunity

In majority of cases of T1DM, IAA, and IA2 antibodies are believed toappear first.40 MICA molecules are a part of innate immune system that in-teract with and activate NK cells and gdT.17 The role of polymorphic MICAmolecules in T1DM pathogenesis is not known. However, we speculate thatafter an environmental trigger, for example, viral infection, MICA moleculesare upregulated, probably, on pancreas or beta cells in specific. These MICAmolecules being a part of innate immune system apparently play a role in theinitial stages of autoimmune reaction. In this regard, it is a very interestingobservation that MICA gene polymorphism especially genotype 5/5 is associ-ated with the formation IAA and IA2 antibodies, which are believed to formearly during the autoimmune reaction. Another interesting observation wasthat all subjects carrying MICA5/5 developed at least one of the three antibod-ies tested. Thus, the presence of MICA5/5 in addition to IAA or IA2 would bea valuable marker for prediction strategies.

MICA5.1 has been associated with older onset of T1DM.16 Also, frequencyof GAD65 antibodies is positively and IAA and IA2 antibodies is negativelyassociated with the age-at-onset of the disease.11 In our analysis, MICA5.1 wasnegatively associated with the formation of IAA and IA2 antibodies consideredindividually or in combination. Interestingly, MICA5.1 was associated with theformation of GAD65 antibodies before correction of P value (P = 0.043, Pc =NS; data not shown). This hints toward the importance of MICA5.1 in GAD65antibody formation, which is a marker for the older onset of T1DM.

In conclusion, our study suggests that (a) MICA gene polymorphism isassociated with autoantibody formation and (b) MICA gene polymorphismespecially MICA5/5 and –5.1/5.1 are important in early events of autoimmunereaction.

REFERENCES

1. SCHRANZ, D.B. & A. LERNMARK. 1998. Immunology in diabetes: an update. Dia-betes Metab. Rev. 14: 3–29.

2. CHRISTIE, M.R. et al. 1994. Antibodies to islet 37k antigen, but not to glutamatedecarboxylase, discriminate rapid progression to IDDM in endocrine autoimmu-nity. Diabetes 43: 1254–1259.


3. BONIFACIO, E. & P.J. BINGLEY. 1997. Islet autoantibodies and their use in predictinginsulin-dependent diabetes. Acta Diabetol. 34: 185–193.

4. BORG, H. et al. 2000. Islet cell antibody frequency differs from that of glutamicacid decarboxylase antibodies/IA2 antibodies after diagnosis of diabetes. ActaPaediatr. 89: 46–51.

5. LINDBERG, B. et al. 1999. Islet autoantibodies in cord blood from children whodeveloped type I (insulin-dependent) diabetes mellitus before 15 years of age.Diabetologia 42: 181–187.

6. SEISSLER, J. et al. 1996. Combined screening for autoantibodies to IA-2 and anti-bodies to glutamic acid decarboxylase in first degree relatives of patients withIDDM. The DENIS Study Group. Deutsche Nikotinamid Interventions-Studie.Diabetologia 39: 1351–1356.

7. TUOMILEHTO, J. & H. YLIHARSILA. 1998. Antibodies as predictors of insulin-dependent diabetes mellitus before the clinical onset. Nutrition 14: 403–405.

8. DECOCHEZ, K. et al. 2000. High frequency of persisting or increasing islet-specificautoantibody levels after diagnosis of type 1 diabetes presenting before 40 yearsof age. The Belgian Diabetes Registry. Diabetes Care 23: 838–844.

9. REDONDO, M.J. & G.S. EISENBARTH. 2002. Genetic control of autoimmunity intype I diabetes and associated disorders. Diabetologia 45: 605–622.

10. GRAHAM, J. et al. 1999. Negative association between type 1 diabetes and HLADQB1∗0602- DQA1∗0102 is attenuated with age at onset. Swedish ChildhoodDiabetes Study Group. Eur. J. Immunogenet. 26: 117–127.

11. GRAHAM, J. et al. 2002. Genetic effects on age-dependent onset and islet cellautoantibody markers in type 1 diabetes. Diabetes 51: 1346–1355.

12. LESLIE, R.D., M.A. ATKINSON & A.L. NOTKINS. 1999. Autoantigens IA-2 and GADin type I (insulin-dependent) diabetes. Diabetologia 42: 3–14.

13. VANDEWALLE, C.L. et al. 1995. High diagnostic sensitivity of glutamate decar-boxylase autoantibodies in insulin-dependent diabetes mellitus with clinical on-set between age 20 and 40 years. Belgian Diabetes Registry. J. Clin. Endocrinol.Metab. 80: 846–851.

14. GUPTA, M. et al. 2003. Association between the transmembrane region polymor-phism of MHC class I chain related Gene-A and type 1 diabetes mellitus inSweden. Hum. Immunol. 64: 553–561.

15. GAMBELUNGHE, G. et al. 2000. Association of MHC class I chain-related A (MIC-A) gene polymorphism with type I diabetes. Diabetologia 43: 507–514.

16. GAMBELUNGHE, G. et al. 2001. Two distinct MICA gene markers discriminatemajor autoimmune diabetes types. J. Clin. Endocrinol. Metab. 86: 3754–3760.

17. BAHRAM, S. 2000. MIC genes: from genetics to biology. Adv. Immunol. 76: 1–60.18. OTA, M. et al. 1997. Trinucleotide repeat polymorphism within exon 5 of the

MICA gene (MHC class I chain-related gene A): allele frequency data in the ninepopulation groups Japanese, Northern Han, Hui, Uygur, Kazakhstan, Iranian,Saudi Arabian, Greek and Italian. Tissue Antigens 49: 448–454.

19. GROH, V. et al. 1998. Recognition of stress-induced MHC molecules by intestinalepithelial gammadelta T cells. Science 279: 1737–1740.

20. BRAUD, V.M., D.S. ALLAN & A.J. MCMICHAEL. 1999. Functions of nonclassicalMHC and non-MHC-encoded class I molecules. Curr. Opin. Immunol. 11: 100–108.

21. GROH, V. et al. 2001. Costimulation of CD8alphabeta T cells by NKG2D viaengagement by MIC induced on virus-infected cells. Nat. Immunol. 2: 255–260.

22. FLODSTROM, M. et al. 2002. Target cell defense prevents the development of dia-betes after viral infection. Nat. Immunol. 3: 373–382.


23. LEE, Y.J. et al. 2000. Polymorphism in the transmembrane region of the MICAgene and type 1 diabetes. J. Pediatr. Endocrinol. Metab. 13: 489–496.

24. ZAKE, L.N. et al. 2002. MHC class I chain-related gene alleles 5 and 5.1 aretransmitted more frequently to type 1 diabetes offspring in HBDI families. Ann.N. Y. Acad. Sci. 958: 309–311.

25. PARK, Y. et al. 2001. MICA polymorphism is associated with type 1 diabetes inthe Korean population. Diabetes Care 24: 33–38.

26. KAWABATA, Y. et al. 2000. Age-related association of MHC class I chain-relatedgene A (MICA) with type 1 (insulin-dependent) diabetes mellitus. Hum. Im-munol. 61: 624–629.

27. LANDIN-OLSSON, M. et al. 1992. Predictive value of islet cell and insulin autoan-tibodies for type 1 (insulin-dependent) diabetes mellitus in a population-basedstudy of newly-diagnosed diabetic and matched control children. Diabetologia35: 1068–1073.

28. LANDIN-OLSSON, M. et al. 1992. Islet cell and thyrogastric antibodies in 633 con-secutive 15- to 34-yr-old patients in the diabetes incidence study in Sweden.Diabetes 41: 1022–1027.

29. SANJEEVI, C.B. et al. 1995. Polymorphic amino acid variations in HLA-DQ areassociated with systematic physical property changes and occurrence of IDDM.Members of the Swedish Childhood Diabetes Study. Diabetes 44: 125–131.

30. KOCKUM, I. et al. 1999. Complex interaction between HLA DR and DQ in confer-ring risk for childhood type 1 diabetes. Eur. J. Immunogenet. 26: 361–372.

31. PALMER, J.P. et al. 1983. Insulin antibodies in insulin-dependent diabetics beforeinsulin treatment. Science 222: 1337–1339.

32. HEGEWALD, M.J. et al. 1992. Increased specificity and sensitivity of insulin anti-body measurements in autoimmune thyroid disease and type I diabetes. J. Im-munol. Methods 154: 61–68.

33. HAGOPIAN, W.A. et al. 1993. Quantitative assay using recombinant human isletglutamic acid decarboxylase (GAD65) shows that 64K autoantibody positivityat onset predicts diabetes type. J. Clin. Invest. 91: 368–374.

34. HAGOPIAN, W.A. et al. 1995. Glutamate decarboxylase-, insulin-, and islet cell-antibodies and HLA typing to detect diabetes in a general population-basedstudy of Swedish children. J. Clin. Invest. 95: 1505–1511.

35. FALORNI, A. et al. 1994. Radioimmunoassay detects the frequent occurrence of au-toantibodies to the Mr 65,000 isoform of glutamic acid decarboxylase in Japaneseinsulin-dependent diabetes. Autoimmunity 19: 113–125.

36. KAWASAKI, E. et al. 1996. Autoantibodies to protein tyrosine phosphatase-likeproteins in type I diabetes. Overlapping specificities to phogrin and ICA512/IA-2. Diabetes 45: 1344–1349.

37. LAN, M.S. et al. 1994. Molecular cloning and identification of a receptor-typeprotein tyrosine phosphatase, IA-2, from human insulinoma. DNA Cell Biol.13: 505–514.

38. MIETTINEN, O. 1976. Estimability and estimation in case-referent studies. Am. J.Epidemiol. 103: 226–235.

39. WOOLF, B. 1955. On estimating the relation between blood group and disease. Ann.Hum. Genet. 19: 251–253.

40. WINTER, W.E., N. HARRIS & D. SCHATZ. 2002. Immunological markers in thediagnosis and prediction of autoimmune type 1a diabetes. Clin. Diabetes 20:183–191.

Documents

MHC Class I Chain-Related Gene-A Is Associated with IA2 and IAA but Not GAD in Swedish Type 1 Diabetes Mellitus