Class II HLA genotype in fulminant type 1 diabetes: A nationwide survey with reference to glutamic acid decarboxylase antibodies

Aims/Introduction: Fulminant type 1 diabetes is a subtype of type 1 diabetes characterized by a remarkably abrupt onset of insulin‐deficient hyperglycemia within a few days. The aim of the present study was to clarify characteristic class II HLA genotypes in a large number of patients with fulminant type 1 diabetes to date. Materials and Methods: We analyzed the HLA‐DRB1 and DQB1 genotypes, and their haplotypes in 207 patients with fulminant type 1 diabetes and 325 control subjects in the Japanese population. Results: The frequencies of the DRB1*04:05‐DQB1*04:01 and DRB1*09:01‐DQB1*03:03 haplotypes were significantly higher, and those of the DRB1*01:01‐DQB1*05:01, DRB1*15:02‐DQB1*06:01 and DRB1*08:03‐DQB1*06:01 haplotypes were significantly lower in patients with fulminant type 1 diabetes than in the control subjects. Combination analysis showed that the frequencies of homozygotes with DRB1*04:05‐DQB1*04:01 [odds ratio (OR) 7.0] and DRB1*09:01‐DQB1*03:03 (OR 9.5) were significantly higher in patients with fulminant type 1 diabetes. Within a limited portion of patients with fulminant type 1 diabetes with antibodies to glutamic acid decarboxylase (GADab; n = 25), the frequency of DRB1*09:01‐DQB1*03:03, but not DRB1*04:05‐DQB1*04:01, was significantly higher than in control subjects (44.0% vs 13.7%; Pc < 0.05, OR 5.0). [Correction to last line of Results, added after online publication 29 July 2011: “OR 5.1” is changed to “OR 5.0”.] Conclusions: Our large‐scale study showed the characteristic class II HLA genotypes in fulminant type 1 diabetes, and implicated that genetic contribution to disease susceptibility is distinct between GADab‐positive and GADab‐negative fulminant type 1 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00139.x, 2012)     

Genetics of the HLA Region in the Prediction of Type 1 Diabetes

Type 1 diabetes (T1D) is one of the most widely studied complex genetic disorders, and the genes in HLA are reported to account for approximately 40–50% of the familial aggregation of T1D. The major genetic determinants of this disease are polymorphisms of class II HLA genes encoding DQ and DR. The DR-DQ haplotypes conferring the highest risk are DRB1*03:01-DQA1*05:01-DQB1*02:01 (abbreviated “DR3”) and DRB1*04:01/02/04/05/08-DQA1*03:01-DQB1*03:02/04 (or DQB1*02; abbreviated “DR4”). The risk is much higher for the heterozygote formed by these two haplotypes (OR = 16.59; 95% CI, 13.7–20.1) than for either of the homozygotes (DR3/DR3, OR = 6.32; 95% CI, 5.12–7.80; DR4/DR4, OR = 5.68; 95% CI, 3.91). In addition, some haplotypes confer strong protection from disease, such as DRB1*15:01-DQA1*01:02-DQB1*06:02 (abbreviated “DR2”; OR = 0.03; 95% CI, 0.01–0.07). After adjusting for the genetic correlation with DR and DQ, significant associations can be seen for HLA class II DPB1 alleles, in particular, DPB1*04:02, DPB1*03:01, and DPB1*02:02. Outside of the class II region, the strongest susceptibility is conferred by class I allele B*39:06 (OR =10.31; 95% CI, 4.21–25.1) and other HLA-B alleles. In addition, several loci in the class III region are reported to be associated with T1D, as are some loci telomeric to class I. Not surprisingly, current approaches for the prediction of T1D in screening studies take advantage of genotyping HLA-DR and HLA-DQ loci, which is then combined with family history and screening for autoantibodies directed against islet-cell antigens. Inclusion of additional moderate HLA risk haplotypes may help identify the majority of children with T1D before the onset of the disease.     

HLA-DRB1/DQB1 susceptibility for autoimmune polyglandular syndrome type II and III in south of Tunisia

Objectives

The aim of our study was to investigate the association of HLA-DRB1 and HLA-DQB1 alleles with autoimmune polyglandular syndromes (APS) type II and III in a southern Tunisian population.

Patients and methods

Sixty-two unrelated patients with APSII (n = 20) and APSIII (n = 42) and 146 healthy controls were genotyped for HLA class II alleles (DRB1*, DQB1*) by PCR-SSP technique.

Results

An increased frequencies of HLA-DQB1*03:02 (P = 0,02; OR = 2.98) in APSII patients, HLA-DRB1*03 (P = 3 10⁻⁶; OR = 4.28) and HLA-DQB1*02:01 (P = 0.04; OR = 1.95) in APSIII patients were found compared to healthy controls. Study of the HLA-DRB1*;DQB1* haplotype frequencies showed a higher occurrence of DRB1*04;DQB1*03:02 and DRB1*03;DQB1*02:01 in APSII patients (P = 4 10⁻³; OR = 3.31 and P = 0.03; OR = 2.74 respectively) whereas APSIII was only associated with DRB1*03;DQB1*02:01 (P = 7.2 10⁻⁸, OR = 4.71).

Conclusion

Our data suggest that the variation in class II HLA alleles and haplotypes could be a genetic factor involved in the susceptibility of APS syndrome.     

Newborn screening for HLA markers associated with IDDM: Diabetes Autoimmunity Study in the Young (DAISY)

Summary Autoimmunity causing insulin-dependent diabetes mellitus (IDDM) begins in early childhood due to interactions between genes and unknown environmental factors that may be identified through follow-up of a large cohort of genetically susceptible children. Such a cohort has been established using a simple and rapid cord blood screening for HLA alleles. The DRB1 and DQB1 second exon sequences were co-amplified using the polymerase chain reaction and hybridized with single and pooled sequence-specific oligonucleotide probes. Four individual probes were used to detect the susceptibility alleles DRB1^*03, DRB1*04, and DQB1^*0302 as well as the usually protective DRB1*15/16 (DR2) alleles. In addition, pooled probes allow the distinction of DR3/3 from the DR3/x genotype (where x is neither DR2, 3, nor 4) and DR4/4 from DR4/x. Among 5000 newborns from the general Denver population, we have found the high-risk genotype (DRB1^*03/DRB1*04, DQB1^*0302) to be present in 2.4 % of non-Hispanic whites, 2.8 % of Hispanics, and 1.6 % of African Americans. The moderate-risk genotypes (DRB1*04, DQB1^*0302/DRB1*04, DQB1^*0302, DRB1*04, DQB1^*0302/x, or DRB1*03/DRB1^*03) are present in 17 % of American non-Hispanic whites, 24 % of Hispanics and in 10 % of African Americans. These results demonstrate the feasibility of a large-scale newborn screening for genes associated with IDDM. The ultimate role for such a screening in future routine prediction and prevention of IDDM will depend on the availability of an effective and acceptable form of clinical intervention. [Diabetologia 1996) 39: 807–812] Received: 21 July 1995 and in revised form: 7 December 1995     

HLA class II gene associations in African American Type 1 diabetes reveal a protective HLA‐DRB1*03 haplotype

Aims

Owing to strong linkage disequilibrium between markers, pinpointing disease associations within genetic regions is difficult in European ancestral populations, most notably the very strong association of the HLA‐DRB1*03‐DQA1*05:01‐DQB1*02:01 haplotype with Type 1 diabetes risk, which is assumed to be because of a combination of HLA‐DRB1 and HLA‐DQB1. In contrast, populations of African ancestry have greater haplotype diversity, offering the possibility of narrowing down regions and strengthening support for a particular gene in a region being causal. We aimed to study the human leukocyte antigen (HLA) region in African American Type 1 diabetes.

Methods

Two hundred and twenty‐seven African American patients with Type 1 diabetes and 471 African American control subjects were tested for association at the HLA class II genes, HLA‐DRB1, HLA‐DQA1, HLA‐DQB1 and 5147 single nucleotide polymorphisms across the major histocompatibility complex region using logistic regression models. Population admixture was accounted for with principal components analysis.

Results

Single nucleotide polymorphism marker associations were explained by the HLA associations, with the major peak over the class II loci. The HLA association overall was extremely strong, as expected for Type 1 diabetes, even in African Americans in whom diabetes diagnosis is heterogeneous. In addition, there were unique features: the HLA‐DRB1*03 haplotype was split into HLA‐DRB1*03:01, which confers greatest susceptibility in these samples (odds ratio 3.17, 95% CI 1.72–5.83) and HLA‐DRB1*03:02, an allele rarely observed in Europeans, which confers the greatest protection in these African American samples (odds ratio 0.22, 95% CI 0.09–0.55).

Conclusions

The unique diversity of the African HLA region we have uncovered supports a specific and major role for HLA‐DRB1 in HLA‐DRB1*03 haplotype‐associated Type 1 diabetes risk.     

Relationship between HLA-DQ and -DR genotypes and clinical characteristics in a French population of Type 1 diabetic patients.

AIMS: The present study was designed to look for a heterogeneity in the association between Type 1 diabetes mellitus (DM) and class II alleles of major histocompatibility complex (MHC) according to clinical presentation and C-peptide secretion during the first year of the disease, in a population living in south of France. METHODS: HLA DRB1 and DQB1 genotypes were determined in 129 Caucasoid patients with Type 1 DM and compared to a control group (n = 88). In a subgroup of 46 young adult diabetic patients, basal and postglucagon C-peptide secretion was followed during the first year of the disease (at 0, 1, 3, 6, 9 and 12 months). RESULTS: The two main haplotypes associated with Type 1 DM were DRB1*04DQB1*0302 and DRB1*03DQB1*02. The genotypes DRB1* 04DQB1 *0302/DRB1*04DQB1*0302 and DRB1 *03DQB1*02/DRB1*04DQB1* 0302 were associated with an early onset of diabetes, while homozygosity for DRB1*03DQB1*02 was characterized by later onset. Levels of residual insulin secretion in patients genotyped DRB1*03DQA1*0501DQB1* 02/DRB1* 04DQA1*0301DQB1*0302 were higher than in patients genotyped DRB1* 3DQA1*0501DQB1*02/DRB1*XDQA1*XDQB1*X or DRB1* XDQA1* XDQB1*X/DRB1*XDQA1*XDQB1*X. CONCLUSIONS: This study confirms some clinical heterogeneity of Type 1 DM linked to HLA DR and DQ genotypes, and leads to a paradoxical finding: DQB1*02/ DQB1*0302 combination predisposes to an early onset in the whole population but residual secretion of insulin disappears more slowly in a subgroup of young adults with recently diagnosed diabetes. These data suggest that interrelations between MHC genotype and diabetogenic process could be different at various ages of life.     

Differential association of HLA with three subtypes of type 1 diabetes: fulminant, slowly progressive and acute-onset

Aim/hypothesis

We sought to clarify similarities and differences in the contribution of HLA to genetic susceptibility to three subtypes of type 1 diabetes: acute-onset, fulminant and slowly progressive.

Methods

We genotyped 545 Japanese patients with type 1 diabetes (338 acute-onset, 80 fulminant, 127 slowly progressive) and 396 control participants at HLA-DRB1, -DQB1, -A, -B and -C, and at 101 candidate single nucleotide polymorphisms (SNPs) in an 8.5 Mb region of the extended HLA.

Results

DRB1*0405-DQB1*0401, DRB1*0802-DQB1*0302 and DRB1*0901-DQB1*0303 were associated with acute-onset type 1 diabetes, with the DRB1*0405-DQB1*0401/DRB1*0802-DQB1*0302 genotype achieving the highest odds ratio of 42.7. DRB1*1501-DQB1*0602 and DRB1*1502-DQB1*0601 were negatively associated with acute-onset type 1 diabetes. A similar tendency was observed for slowly progressive type 1 diabetes. In contrast, only DRB1*0405-DQB1*0401 was associated with fulminant type 1 diabetes, with the DRB1*0405-DQB1*0401/DRB1*0405-DQB1*0401 genotype showing the highest odds ratio of 11.2. DRB1*0802-DQB1*0302, DRB1*0405-DQB1*0401/DRB1*0802-DQB1*0302 and DRB1*1501-DQB1*0602 were not associated with fulminant type 1 diabetes. The association of class I alleles and a panel of SNPs in an extended HLA region with fulminant type 1 diabetes was also different from that seen for the acute-onset and slowly progressive forms. The presence of both one and two susceptible haplotypes conferred susceptibility to slowly progressive type 1 diabetes, whereas the presence of two susceptible haplotypes was required to confer susceptibility to acute-onset and fulminant type 1 diabetes.

Conclusions/interpretation

These data suggest that HLA associations with fulminant type 1 diabetes are qualitatively different from those with other subtypes of type 1 diabetes, whereas the HLA contribution to slowly progressive type 1 diabetes is qualitatively similar to, but quantitatively different from, that in acute-onset type 1 diabetes.     

Receptor for advanced glycation end-products (RAGE) provides a link between genetic susceptibility and environmental factors in type 1 diabetes

Aims/hypothesis

This group of studies examines human genetic susceptibility conferred by the receptor for advanced glycation end-products (RAGE) in type 1 diabetes and investigates how this may interact with a western environment.

Methods

We analysed the AGER gene, using 13 tag SNPs, in 3,624 Finnish individuals from the FinnDiane study, followed by AGER associations with a high risk HLA genotype (DR3)-DQA1*05-DQB1*02/DRB1*0401-DQB1*0302 (n?=?546; HLA-DR3/DR4), matched in healthy newborn infants from the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Study (n?=?373) using allelic analysis. We also studied islets and circulating RAGE in NODLt mice.

Results

The rs2070600 and rs17493811 polymorphisms predicted increased risk of type 1 diabetes, whereas the rs9469089 SNP was related to decreased risk, on a high risk HLA background. Children from the DIPP study also showed a decline in circulating soluble RAGE levels, at seroconversion to positivity for type 1 diabetes-associated autoantibodies. Islet RAGE and circulating soluble RAGE levels in prediabetic NODLt mice decreased over time and were prevented by the AGE lowering therapy alagebrium chloride. Alagebrium chloride also decreased the incidence of autoimmune diabetes and restored islet RAGE levels.

Conclusions/interpretation

These studies suggest that inherited AGER gene polymorphisms may confer susceptibility to environmental insults. Declining circulating levels of soluble RAGE, before the development of overt diabetes, may also be predictive of clinical disease in children with high to medium risk HLA II backgrounds and this possibility warrants further investigation in a larger cohort.     

The HLA-B*3906 allele imparts a high risk of diabetes only on specific HLA-DR/DQ haplotypes

Aims/hypothesis

We investigated the risk associated with HLA-B*39 alleles in the context of specific HLA-DR/DQ haplotypes.

Methods

We studied a readily available dataset from the Type 1 Diabetes Genetics Consortium that consists of 2,300 affected sibling pair families genotyped for both HLA alleles and 2,837 single nucleotide polymorphisms across the major histocompatibility complex region.

Results

The B*3906 allele significantly enhanced the risk of type 1 diabetes when present on specific HLA-DR/DQ haplotypes (DRB1*0801-DQB1*0402: p?=?1.6?×?10^?6, OR 25.4; DRB1*0101-DQB1*0501: p?=?4.9?×?10^?5, OR 10.3) but did not enhance the risk of DRB1*0401-DQB1*0302 haplotypes. In addition, the B*3901 allele enhanced risk on the DRB1*1601-DQB1*0502 haplotype (p?=?3.7?×?10^?3, OR 7.2).

Conclusions/interpretation

These associations indicate that the B*39 alleles significantly increase risk when present on specific HLA-DR/DQ haplotypes, and HLA-B typing in concert with specific HLA-DR/DQ genotypes should facilitate genetic prediction of type 1 diabetes, particularly in a research setting.     

Transfer of the shared epitope through microchimerism in women with rheumatoid arthritis

Objective

Rheumatoid arthritis (RA) is an autoimmune disease that affects mostly women and is associated with HLA–DRB1 genes having in common a shared epitope sequence. In parallel, cells and/or DNA originating from pregnancy (microchimerism) persist for decades and could contribute to autoimmunity. The aim of this study was to examine whether microchimerism may be a source of the shared epitope among women with RA.

Methods

Women with RA and healthy women who lacked RA‐associated genes such as HLA–DRB1*01 (n = 33 and n = 46, respectively) and/or HLA–DRB1*04 (n = 48 and n = 64, respectively), were tested for DRB1*01 or DRB1*04 microchimerism by HLA‐specific quantitative polymerase chain reaction assays. As controls, alleles not associated with RA (DQB1*02 and DRB1*15/16) were also analyzed.

Results

Compared with healthy women, women (42% with RA had a higher frequency and higher levels of DRB1*04 microchimerism versus 8%; P = 0.00002) as well as DRB1*01 microchimerism (30% versus 4%; P = 0.0015). Moreover, no difference in microchimerism was observed for alleles not associated with RA.

Conclusion

Women with RA had microchimerism with RA‐associated HLA alleles, but not with non–RA‐associated HLA alleles, more often and at higher levels compared with healthy women. These observations are the first to indicate that microchimerism can contribute to the risk of an autoimmune disease by providing HLA susceptibility alleles.

     

Histocompatibility leucocyte antigens and closely linked immunomodulatory genes in autoimmune thyroid disease

OBJECTIVES: Associations between autoimmune thyroid disease and antigens of the major histocompatibility complex (MHC) have long been recognized. Graves' disease (GD) is associated with the histocompatibility leucocyte antigen (HLA) haplotype A*01-B*0801-DRB1*0301-DQA1*0501-DQB1*0201 (or B8/DR3) whereas autoimmune hypothyroidism (AIH) has been weakly associated with HLA DRB1*03, *04 and *11/*12 alleles (or DR3, DR4 and DR5). However, the presence of important immunoregulatory genes within the HLA Class II and III regions raises the possibility that these genes harbour the primary susceptibility locus. This study examines genetic variation across the MHC in UK Caucasoid subjects with autoimmune thyroid disease. PATIENTS AND METHODS: DNA extracted from venous blood samples from 215 patients with autoimmune thyroid disease (GD 135, AIH 77) and 267 control subjects was analysed. Genotyping was performed using polymerase chain reaction and sequence specific primers for HLA Class I and II alleles and polymorphisms within the TAP1, TAP2, tumour necrosis factor (TNF), lymphotoxin alpha (LTalpha), heat shock protein (HSP)70-1, HSP70-2 and HSP70-Hom genes. RESULTS: For GD, the strongest association was with DRB1*03 [56% patients positive vs. 24% controls, P = 2 x 10(-10), odds ratio (OR) 4.0]. Positive associations were also seen for DRB1*03 linked alleles, B*0801, DRB3*01/02, DQA1*05, DQB1*02 and DPB1*0101 (OR 2.3-3.4). Specific TNF and LTalpha alleles were strongly associated with GD (Pc = 3 x 10(-5) and 0.001) and weak associations were seen for HSP70-1 + 190C and HSP70-2 + 1267G polymorphisms (Pc = 0.05 and 0.01). These associations were not significant when DRB1*03 status was considered. Patients with AIH showed only a weak association with DQB1*03 (P = 0.02). CONCLUSIONS: These results show that, of the polymorphisms tested within the MHC, GD is most strongly associated with DRB1*03, and associations with other immunoregulatory genes previously described in Caucasian subjects most likely reflect linkage disequilibrium. AIH differs from GD, being less influenced by the MHC region.     

Human leukocyte antigen class II molecules confer both susceptibility and progression in Japanese patients with primary biliary cirrhosis

Along with twin and family studies, recent genome-wide association studies suggest that genetic factors contribute to the susceptibility and severity of primary biliary cirrhosis (PBC). Although several reports have demonstrated that the human leukocyte antigen (HLA) DRB1*08:03 allele is associated with disease susceptibility in Japan, the precise analysis of HLA haplotypes and the role of amino acid alignment have not been fully clarified. We investigated HLA class I A, B, and C and HLA class II DRB1 and DQB1 alleles and haplotypes in 229 Japanese patients with PBC and compared them with the published data of 523 healthy subjects. Significant associations were found with PBC susceptibility for the DRB1*08:03-DQB1*06:01 (13% versus 6%; P = 0.000025; odds ratio [OR] = 2.22) and DRB1*04:05-DQB1*04:01 haplotypes (17% versus 13%; P = 0.044; OR = 1.38). Conversely, there were significant protective associations with the DRB1*13:02-DQB1*06:04 (2% versus 5%; P = 0.00093; OR = 0.27) and DRB1*11:01-DQB1*03:01 haplotypes (1% versus 4%; P = 0.03; OR = 0.37). The frequency of the DRB1*09:01-DQB1*03:03 haplotype was significantly higher in patients who had received orthotopic liver transplantation (33% versus 11%; P = 0.0012; OR = 3.96). Furthermore, the frequency of serine at position 57 (P = 0.0000015; OR = 1.83) of the DRβchain differed the most in patients with PBC, compared with healthy subjects. CONCLUSION: This study established the role of HLA haplotypes in determining PBC susceptibility and progression in the Japanese population. Further resequencing of the HLA region is required to more precisely identify the genetic components of PBC.     

Molecular typing of HLA-class II alleles reveals an association with autoantibodies and disease subsets of systemic sclerosis in a North Indian (Kashmir) population

Aim of the workTo identify specific human leukocyte antigen (HLA)-Class II (DRB/DQB1/DPB1) alleles associated with systemic sclerosis (SSc) and to explore their relation with SSc autoantibodies, clinical manifestations, and disease subsets.Patients and methodsHLA-class II alleles (DRB1/DRB3/DRB4/DRB5/DQB1) were determined by DNA typing in 80 SSc cases and 60 matched controls and HLA-DPB1 in 40 SSc patients and 30 controls by allele-specific-polymerase chain reaction with sequence-specific primers (PCR-SSP).ResultsThe mean age of SSc patients was 36.9 ± 9.4 years; 76 females and 4 males (F:M 19:1) and a disease duration of 5.3 ± 3.3 years, they were 43(53.7%) limited and 37(46.2%) diffuse subtypes. SSc was significantly associated with DRB1*11, DRB1*01, DQB1*04, and DQB1*03*03 in a >4-fold manner, whereas DPB1*04 had a >7-fold increased risk compared to controls. There was a strong association between DRB1*11 (p = 0.04), DQB1*03*03 (p = 0.005), and DPB1*13 (p = 0.009) with anti-topoisomerase I (anti-topoI) whereas the frequency of DRB1*01 (p < 0.0001) was increased in patients with anti-centromere (ACA) positive SSc compared those negative (56% vs 25%; p < 0.0001). DRB1*03, DRB1*15, and DQB1*03*01 were SSc protective alleles in patients with positive ACA. Anti-topo I was associated with interstitial lung disease (ILD) (p < 0.01), whereas ACA with pulmonary arterial hypertension (PAH) (p = 0.01) and protection against ILD (p < 0.001). In addition, HLA-DRB1*03, DQB1*03*01and DPB1*03 were more frequent in patients with ILD than in patients without.ConclusionAssociations between specific HLA-class II alleles with certain SSc-specific autoantibodies (anti-topo I and ACA) were identified. Specific HLA associations with clinical and serological subtypes could serve as biomarkers of disease severity and progression in SSc.     

Frequency of DRB1-DQB1 two-locus haplotypes in tuberculosis: preliminary report

Analysis of correlation between tuberculosis (TB) and human leukocyte antigen (HLA) in populations from Asia and Latin America has shown conflicting results. The aim of this study was to evaluate the frequency of HLA-DRB1-DQB1 two-locus haplotypes of 61 TB patients and 125 healthy volunteers in the same ethnic group in Poland. DRB1 and DQB1 alleles were determined by PCR-SSP "low-resolution" and "high-resolution" methods. Our study showed that DRB1*1601 and DQB1*0502 alleles were more frequent, whereas DQB1*0201 was rarer in TB than in controls. DRB1*16-DQB1*05, DRB1*04-DQB1*03 and DRB1*1601-DQB1*0502 haplotype were more common, and DRB1*11-DQB1*03 less frequent in TB in comparison to controls. Positive linkage disequilibrium (LD) for DRB1*01-DQB1*05, DRB1*03-DQB1*02, DRB1*11-DQB1*03, DRB1*13-DQB1*06 and DRB1*15-DQB1*06 was found in controls. A trend towards the positive LD for DRB1*01-DQB1*05, DRB1*03-DQB1*02, DRB1*11-DQB1*03, DRB1*15-DQB1*06 and DRB1*16-DQB1*05 was shown in TB. The trend towards the positive LD for DRB1*16-DQB1*05 haplotype in TB patients was not observed in the control group. It seems likely that the presence of DRB1*1601, DQB1*0502 alleles and DRB1*1601-DQB1*0502, DRB1*04-DQB1*03, DRB1*14-DQB1*05 haplotypes may be related to a higher risk of developing TB, whereas low frequency of DQB1*0201 and DRB1*11-DQB1*03 haplotype may be linked to the resistance to TB.     

HLA-DR-DQ haplotypes and genotypes in Finnish patients with rheumatoid arthritis

OBJECTIVES: To elucidate the contribution of HLA-DR-DQ haplotypes and their genotypic combinations to susceptibility to rheumatoid arthritis, and to evaluate the various models for HLA associated risk for the disease in a series of Finnish patients. METHODS: 322 Finnish patients with rheumatoid arthritis were typed for common north European HLA-DR-DQ haplotypes and compared with a series of 1244 artificial family based control haplotypes. RESULTS: The association of the so called shared epitope (SE) haplotypes (DRB1*0401, *0404, *0408, and *01) with rheumatoid arthritis was confirmed. The DRB1*0401 haplotypes carried a far stronger risk for the disease than the (DRB1*01/10)-(DQA1*01)-DQB1*0501 haplotypes. Seven protective HLA haplotypes--(DRB1*15)-(DQA1*01)-DQB1*0602; (DRB1*08)-(DQA1*04)-DQB1*04; (DRB1*11/12)-DQA1*05-DQB1*0301; (DRB1*1301)-(DQA1*01)-DQB1*0603; (DRB1*1302)-(DQA1*01)-DQB1*0604; (DRB1*07)-DQA1*0201-DQB1*0303; and (DRB1*16)- (DQA1*01)-DQB1*0502--were identified. In accordance with the reshaped shared epitope hypothesis, all the protective DRB1 alleles in these haplotypes share either isoleucine at position 67 or aspartic acid at position 70 in their third hypervariable region motif. However, differences in the disease risk of haplotypes carrying the same DR but different DQ alleles were also found: (DRB1*07)-DQA1*0201-DQB1*0303 was protective, while (DRB1*07)-DQA1*0201-DQB1*02 was neutral. The same haplotypes carried different risks for rheumatoid arthritis depending on their combination in genotypes. CONCLUSIONS: When assessing the influence of HLA genes on the susceptibility to rheumatoid arthritis, not only should the HLA-DR or -DQ alleles or haplotypes be unravelled but also the genotype. The effect of HLA class II region genes is more complicated than any of the existing hypotheses can explain.     

Genetic contribution of major histocompatibility complex class II region to type 1 autoimmune hepatitis susceptibility in Venezuela.

AIMS: Autoimmune hepatitis (AIH) is a progressive liver disease characterized by the presence of circulating autoantibodies, hypergammaglobulinaemia and a favourable response to immunosuppressive treatment. Although the pathogenesis of type 1 AIH is unknown, disease susceptibility is partially determined by genes linked to the class II region of the major histocompatibility complex. Type 1 AIH has been associated with DRB1*03, DRB1*04 and DRB3 alleles in European and North American Caucasians, with DRB1*0405 in Japanese, with DRB1*0404 in Mexican, and with DRB1*1301 in Argentinean populations. METHODS: To analyse the molecular basis of these associations in Venezuela (mestizo population), we examined the frequency of human leucocyte antigens (HLA)-A -B -C, HLA-DQ and HLA-DR genes by low- and high-resolution oligonucleotide typing in a population of 41 type 1 AIH patients and 111 ethnic- and aged-matched healthy subjects. RESULTS: The frequencies of both DRB1(*)1301 (P<0.0001) and DRB1*0301 (P<0.005) were significantly higher in patients than in controls. In addition, patients showed a strong association with the DRB3 allele (P<0.01). In contrast, the DQB1*04 allele was significantly decreased in the patient group (P<0.01). The frequencies of haplotypes A*01-B*08-DQB1*02-DRB1*03-DRB3, DQB1*05-DRB1*1301, DQB1*06-DRB1*1301 and A*02-DRB1*1301, B*45-DRB3 were significantly increased in type 1 AIH patients compared with the controls (P<0.01). CONCLUSIONS: In conclusion, our data indicate that type 1 AIH predisposition in a Venezuelan mestizo population of different ethnic backgrounds is associated with DRB1*1301 and DRB1*0301 alleles. In addition, our findings suggest that protection against disease might be conferred by the DQB1*04 allele, with distinct ethnic differences from other populations.     

Use of class I and class II HLA loci for predicting age at onset of type 1 diabetes in multiple populations

Aims/hypothesis

The study aimed to assess, in multiple populations, the role of HLA alleles on early and late age at onset of type 1 diabetes.

Methods

Stepwise linear regression models were used to determine which HLA class I and class II risk alleles to include. High-resolution genotyping data for patients from the Type 1 Diabetes Genetics Consortium (T1DGC) collection (n?=?2,278) and four independent cohorts from Denmark, Sardinia and the USA (Human Biological Data Interchange [HBDI] and Joslin Diabetes Center) (n?=?1,324) (total n?=?3,602) were used to assess the role of HLA variation on age of onset and predict early onset (age ≤5?years) and late onset (age ≥15?years) of type 1 diabetes.

Results

In addition to carriage of HLA class I alleles A*24:02, B*39:06, B*44:03 and B*18:01, HLA class II DRB1-DQB1 loci significantly contributed to age at onset, explaining 3.4% of its variance in the combined data. HLA genotypes, together with sex, were able to predict late onset in all cohorts studied, with AUC values ranging from 0.58 to 0.63. Similar AUC values (0.59–0.70) were obtained for early onset for most cohorts, except in the Sardinian study, in which none of the models tested had significant predictive power.

Conclusions/interpretation

HLA associations with age of onset are consistent across most white populations and HLA information can predict some of the risk of early and late onset of type 1 diabetes. Considerable heterogeneity was observed between Sardinian and other populations, particularly with regard to early age of onset.     

Rare human leukocyte antigen genotype in two siblings with type 1 diabetes in a Japanese family clustered with type 1 diabetes

Multiplex families with type 1 diabetes are important for identification of rare variants that cannot be identified in case–control association studies. The very low incidence of type 1 diabetes in the Japanese population, however, makes identification of such families difficult. We identified a Japanese family in which three members developed type 1 diabetes, and studied the genotype of the human leukocyte antigen. All three members with type 1 diabetes had the DRB1*08:02‐DQB1*03:02 haplotype, which is specific to the Asian population and strongly susceptible for type 1 diabetes. In particular, a proband and his sister had the same genotype, DRB1*08:02‐DQB1*03:02/DRB1*08:02‐DQB1*03:02, which is extremely rare even in the Japanese population. Both parents also had DRB1*08:02‐DQB1*03:02, but in combination with different human leukocyte antigen haplotypes. Weakly susceptible DRB1*13:02‐DQB1*06:04 was present in the affected mother, and resistant DRB1*15:01‐DQB1*06:02 in the unaffected father. These data suggest DRB1*08:02‐DQB1*03:02 to be a contributing factor for familial clustering of type 1 diabetes in this family.     

HLA-dependent autoantibodies against post-translationally modified collagen type II in type 1 diabetes mellitus

Aims/hypothesis

In this study the involvement of oxidative stress in type 1 diabetes mellitus autoimmunity and the possible association with rheumatoid arthritis (RA) was investigated. We tested the hypothesis that oxidative stress induced by chronic hyperglycaemia triggers post-translational modifications and thus the formation of neo-antigens in type 1 diabetes, similar to the ones found in RA.

Methods

Collagen type II (CII), a known autoantigen in RA, was treated with ribose and various reactive oxygen species (ROS). Levels of antibodies specific to native and ROS-modified CII (ROS-CII) were compared in type 1 diabetes, type 2 diabetes and healthy controls, and related to the HLA genotype.

Results

Significantly higher binding to ROS-CII vs native CII was observed in type 1 diabetic patients possessing the HLA-DRB1*04 allele irrespective of variables of glucose control (blood glucose or HbA_1c). Type 1 diabetic patients carrying a DRB1*04 allele with the shared epitope showed the highest risk for ROS-CII autoimmunity, while the DRB1*0301 allele was protective. Conversely, native CII autoimmunity was not associated with any specific DRB1 allele. Positive and inverse seroconversion rates of response to ROS-CII were high in DRB1*04-positive type 1 diabetic patients.

Conclusion

Hyperglycaemia and oxidative stress may trigger genetically controlled autoimmunity to ROS-CII and may explain the association between type 1 diabetes mellitus and RA.     

Increased frequency of DRB1*11:01 in anti–hydroxymethylglutaryl‐coenzyme A reductase–associated autoimmune myopathy

Objective

To investigate the association of anti–hydroxymethylglutaryl‐coenzyme A reductase (anti‐HMGCR) myopathy with HLA class I and II antigens.

Methods

HLA antigens were determined in 1) 20 white and 8 African American anti‐HMGCR patients, 2) 487 white and 167 African American controls, and 3) 51 white subjects with mild self‐limited statin intolerance.

Results

White anti‐HMGCR patients had a higher frequency of the combination HLA–DR11, DQA5, and DQB7 than controls or statin‐intolerant subjects (70% versus 17%; odds ratio [OR] 11.7 [95% confidence interval (95% CI) 4.0–35.3], P = 4.1 × 10^?7 and 70% versus 21%; OR 8.3 [95% CI 2.2–33.9], P = 5.4 × 10^?4, respectively). This combination was not increased in African American anti‐HMGCR subjects compared to controls (13% versus 3%; OR 4.6 [95% CI 0.2–53.3], P = 0.2). However, DR11 was increased in African American anti‐HMGCR patients compared to controls (88% versus 21%; OR 26.4 [95% CI 3.1–590.3], P = 0.0002). High‐resolution mapping showed that 95% with DR11 had DRB1*11:01. DQA1 and DQB6 were less frequent in white anti‐HMGCR–positive patients compared to controls (25% versus 65%; OR 0.2 [95% CI 0.1–0.5], P = 5.5 × 10^?4 and 0% versus 45%; OR 0.0 [95% CI 0.0–0.3], P = 2.1 × 10^?5, respectively). DRB11 was not associated with particular disease features.

Conclusion

DRB1*11:01 is associated with an increased risk of anti‐HMGCR myopathy in whites and African Americans. These findings suggest a mechanistic link between statin exposure, increased HMGCR expression, and the possible presentation of HMGCR‐derived peptide(s) by DRB1*11:01.