Genetics of latent autoimmune diabetes in adults.

Slowly progressive insulin-dependent diabetes mellitus (IDDM), like classical IDDM, is also associated with genetic markers. HLA-DR3 but not DR4 is associated with latent autoimmune diabetes in adults (LADA). In GAD65 antibody-positive Finnish LADA patients, DQB1*0302 is positively associated with the disease. Alleles of the MHC class I chain-related A (MICA) gene located centromeric to the HLA-B gene is associated with LADA. Allele 5.1 of MICA was associated with both LADA and adult-onset Italian IDDM patients when compared to controls. This finding was also observed in Indian and Latvian patients with LADA. These findings suggest that certain genetic markers distinguish LADA better.

Prevalence of ICA-12 and other autoantibodies in north Indian patients with early-onset diabetes.

This study attempts to assess the prevalence of various autoantibodies in early-onset diabetics in northern India, with emphasis on antibodies against glutamic acid decarboxylase (GAD65), IA-2, ICA-12, 21-hydroxylase (21-OH), and tissue transglutaminase (TTG). GAD65 and IA-2 antibodies were found to be present in approximately 26% of cases of type 1 diabetes. A subset of patients clinically diagnosed to have MMDM appears to have an autoimmune etiology, with more than 20% showing serpositivity for IA-2 antibodies. Antibodies against ICA-12 were prevalent in both type 1 diabetes and MMDM. Approximately one of seven patients with type 1 diabetes showed erological evidence of celiac disease.

Increased autoantibodies to SOX13 in Swedish patients with type 1 diabetes.

This article aims to estimate the prevalence of SOX13 antibodies in Swedish patients with type 1 diabetes and healthy controls. The patients (n = 102; median age 35 years [range, 9-89]) were newly diagnosed with type 1 diabetes in a defined area in southern Sweden during 1995-1998. Islet cell antibodies (ICA) were analyzed with immunofluorescence, while glutamic acid decarboxylase antibodies (GADA), tyrosine phosphatase antibodies (IA-2A), and antibodies against the transcription factor SOX13 (SOX13Ab) were analyzed with radioimmunoprecipitating assays. SOX13Ab were found in 9.8% (10/102) of type 1 patients compared to 2.0% (2/99) in healthy controls (P = 0.033). At least one of the four autoantibodies (ICA, GADA, IA-2A or SOX13Ab) were identified in 67% (68/102) of the patients. Samples positive for IA-2A were only in one case positive also for SOX13Ab. IA-2A-positive patients were often positive also for ICA and GADA (19/27), and the same combination was also common for SOX13Ab-positive patients (6/10). Only 2.0% (2/102) were positive for SOX13Ab alone. ICA, GADA and IA-2A were more frequent in younger patients (

Autoantibodies to tissue transglutaminase in patients from eastern India with malnutrition-modulated diabetes mellitus, insulin-dependent diabetes mellitus, and non-insulin-dependent diabetes mellitus.

Antibodies to tyrosine phosphatase (IA2-Ab) and glutamate decarboxylase 65 (GAD65-Ab) are major markers for IDDM in Caucasians. TTG-Ab is specific for celiac disease. Celiac disease is caused by ingestion of the protein gliadin, a component of wheat gluten, and usually resolves on its withdrawal. Ten to twenty percent of celiac disease patients also have IDDM. The aim of the study was to estimate the prevalence of TTG-Ab in MMDM (n = 71), IDDM (n = 74), and NIDDM (n = 216) and 122 controls from Cuttack in eastern India. MMDM patients are typically young at onset with low body mass index, require insulin for glycemic control, have insulin resistance, and do not develop ketosis on withdrawal of insulin. TTG-Ab was evaluated by radioimmunoassay using in vitro translated recombinant human 35S-TTG. In controls, TTG-Ab was present in 3/122 (2%); in MMDM, TTG-Ab was present in 14/71 (20%); 11/74 (15%) IDDM (P < 0.05 vs. controls) and 23/216 (11%) NIDDM (P < 0.05 vs. controls) were also positive for TTG-Ab. We conclude that MMDM, IDDM, and NIDDM patients from Cuttack have a significantly high proportion of TTG-Ab compared to healthy controls. The highest significance is seen with MMDM patients. It is important to note that subclinical celiac disease must be considered in the differential diagnosis of MMDM.

GAD65 and ICA512 antibodies in undernourished and normally nourished south Indian patients with diabetes.

The frequency of GAD65 and ICA512 antibodies in Indian IDDM patients is similar to that in Caucasians. The aim of the study was to test whether undernutrition is associated with autoimmunity as evidenced by increased or decreased autoantibody formation in both clinically diagnosed IDDM and NIDDM patients from south India. The prevalence of GAD65 and ICA512 autoantibodies in controls from south India was 4% and 2%, respectively. One hundred thirty-one diabetic patients (undernourished [UNDM], n = 67; and normal nourished [NNDM], n = 64) were assayed for GAD65 and ICA512 autoantibodies. None were obese. All patients were new onset or with duration <5 years. GAD65 autoantibodies were present in 73/131 (55%), and ICA512 antibodies were present in 43/131 (33%) of patients. The results suggest that GAD65 and ICA512 antibody frequencies are neither significantly increased nor decreased in UNDM patients compared to NNDM patients. In addition, the increased frequency of autoantibodies among NIDDM compared to IDDM in both nutrition groups suggests high prevalence of slow-onset IDDM. In conclusion, undernutrition does not predispose to autoimmunity in south Indian diabetic patients.

Islet autoantibodies in Latvian subjects with non-insulin-dependent diabetes mellitus: slow-onset type 1 diabetes or polyendocrine autoimmunity?

In Latvia diabetes mellitus is diagnosed using the WHO's clinical criteria; assays for the detection of autoantibodies are not available, and hence slowly progressive autoimmune diabetes is likely to be missed. Autoantibodies against glutamic acid decarboxylase (GAD65) and protein tyrosine phosphatase (IA-2) among patients with clinically diagnosed NIDDM identify group of patients with slow-onset type 1 diabetes or LADA. The aim of this study was to estimate the risk of polyendocrine autoimmunity among clinically diagnosed NIDDM patients from Latvia. One hundred NIDDM patients and 100 healthy controls were tested for GAD65 and IA-2 autoantibodies as well as 21-hydroxylase (21-OH) and tissue transglutaminase (TTG) antibodies by RIA assay. Age at onset was >or= 30 years, and duration of disease less than 5 years. Of 100 patients, 85 were on oral hypoglycemic agents and 15 were on insulin. Body mass index (BMI) under 19 was recorded in 1% (1 of 100 cases), while overweight (BMI > 25.5 in females and 27 in males) was documented in 45% (45 of 100 cases). GAD65 antibodies were found in 30 of 100 (30%) and IA-2 antibodies in 40 of 100 (40%) patients. Either GAD65 or IA-2 antibodies were found in 55 of 100 (55%). None of the patients carried antibodies against 21-OH and only 1 of 100 (1%) carried antibodies against TTG. From the results obtained in our study we conclude that in Latvian adult NIDDM subjects, islet autoantibodies identify groups of slow-onset type 1 diabetes but not polyendocrine autoimmunity.

Women diagnosed with gestational diabetes mellitus do not carry antibodies against minor islet cell antigens.

Women with gestational diabetes mellitus (GDM) have considerable risk for developing both type 1 and type 2 diabetes in life. Autoantibodies against glutamic acid decarboxylase (GAD65) and tyrosine phosphatase (IA-2) are strongly associated with autoimmune diabetes and can be useful in early identification of the development of type 1 diabetes in women with GDM. On the other hand antibodies against minor islet antigens in adults can be predictors for autoimmune polyendocrine syndrome. The aim of our study was to estimate the prevalence of autoantibodies against minor antigens-tissue transglutaminase (TTG), ICA12, and 21-hydroxylase (21-0H)-in GDM patients from southern India. Eighty-six serum samples from GDM subjects and 114 samples from healthy controls were tested for the presence of GAD65 and IA-2Ab as well as for the presence of 21-OH, TTG, and ICA12Ab by radiobinding assay with in vitro translated recombinant human 35S-GAD65, IA-2, TTG, ICA12, and 21-OH antigens. We observed the presence of GAD65 or IA-2 autoantibodies in 41% (35/86) of GDM patients, while none of the patients tested positive for any of the minor autoantibodies. Our results demonstrate that there is a high prevalence of autoantibodies in GDM subjects that are at higher risk of developing autoimmune diabetes later, but none of the patients carries antibodies against minor antigens, which could predict autoimmune polyendocrine syndrome in adults.

Autoimmune diabetes in 26 villages outside Madras.

Autoimmune diabetes is one of the most common chronic diseases in the world. Autoantibodies against major antigens GAD65 and IA-2 as well as some minor antibodies are markers for autoimmune diabetes already several years before clinical onset in most populations. Screening the population for these autoantibodies can help identify subjects at risk for developing type 1 diabetes. In our study we screened 20,903 inhabitants in 26 villages outside Madras for diabetes. Among them 3.64% were detected to be diabetic. The aim of our study was to detect the presence of glutamic acid decarboxylase (GAD65), tyrosine phosphates (IA-2) and tissue transglutaminase (TTG) antibodies. We studied 169 individuals from this population, 75 of them were diagnosed as diabetics, based on presence of sugar in the urine and an elevated blood sugar, 58 had hypertension, and 36 were healthy subjects. We used radioimmunoassay with in vitro translated and transcribed human recombinant 35S-GAD65, IA-2 and TTG antigens. We observed presence of GAD65Ab in 10%, IA-2Ab in 5%, and TTGAb in 5% in diabetic subjects, while the healthy subjects and people with hypertension didn't carry any of these antibodies. We conclude that prevalence of autoimmune diabetes mellitus based on antibody screening in this population is significantly high.

BCG vaccination and GAD65 and IA-2 autoantibodies in autoimmune diabetes in southern India.

This paper reports a study to determine whether BCG vaccination is associated with an increase or decrease in GAD65 and I-A2 autoantibodies in cases of IDDM and NIDDM in southern India. It is concluded that BCG vaccination has an immunomodulatory role in these diseases.

Antibodies to new beta cell antigen ICA12 in Latvian diabetes patients.

In Latvia diabetes mellitus is diagnosed using the WHO's clinical criteria, and assays for the detection of autoantibodies are not available. In consequence, slowly progressive autoimmune diabetes or LADA is likely to be missed. Antibodies to GAD65 and IA-2 are the major immunological markers in autoimmune diabetes. Recently, a new beta cell antigen, called ICA12, has been identified, which has a homology to the SOX family of transcription factors. The aim of the study was to analyze the prevalence of ICA12 antibodies in diabetes mellitus patients and controls from Latvia and to see whether this antigen is important in revealing autoimmunity when antibodies against major antigens are not present. We studied 88 IDDM patients and 100 NIDDM patients as well as controls for the prevalence of GAD65, IA-2, and ICA12 antibodies by radioligand binding assay (RIA) using (35)S-labeled islet antigens. We found ICA12Abs in 26 of 88 IDDM patients (30%) vs. 4% in healthy controls (4/100) and in 9 of 100 NIDDM patients (9%) vs. 2% controls (2/100). ICA12Abs alone are present in only 3% (3/88) of the patients with IDDM and 1% (1/100) of the NIDDM patients. We conclude that ICA12 represents the minor antigens in autoimmune diabetes and that, as a minor antigen, ICA12 alone does not contribute significantly in revealing new cases of autoimmunity.

Newborn screening for high-risk human leukocyte antigen markers associated with insulin-dependent diabetes mellitus: the ABIS study.

Type 1 (insulin-dependent) diabetes mellitus is associated with specific high-risk HLA DQ and DR haplotypes and islet cell antibodies. IDDM susceptibility in Caucasians is more strongly associated with DQ2/DQ8 (DQA1*0501-DQB1*0201/DQA1*0301-DQB1*0302) and DQ6 (B1*0604) than with DRB1*03/DRB1*04, while a single copy of DQ6 (B1*0602) gives sufficient protection against type 1 diabetes. As a part of the ABIS (All Babies in Southeast Sweden) study we have done typing of DQA1, DQB1, and DRB1 by polymerase chain reaction (PCR) amplification of the second exon of the genes, manually dot-blotting onto nylon membranes synthetic sequence-specific oligonucleotide (SSO) probes, 3' end-labeling with (32)P-dCTP, and hybridization followed by stringency washes and autoradiography using the SSO probe. Among 3756 newborns born in southeast Sweden we have found the high-risk genotype DQ2/DR3-DO8/DR4 to be present in 1%, haplotype DQ8/DR4 in 7.8%, and haplotype DQ2/DR3 in 9.6%. DQ2/DR3 or DQ8/DR4 was carried by 16.4% of newborns; the low-risk DQ6 molecule was carried by newborns as follows: DQ2/DR3-DQ6/DR15, 1.3%; DQ8/DR4-DQ6/DR15, 1.3%; and DQ6/DR15, 9.4%. We conclude from our results that the high incidence of IDDM in Sweden is at least in part due to increased prevalence of high-risk HLA haplotypes compared to protective haplotypes (20% vs. 13%) in the general population.

ICA12 autoantibodies are associated with non-DR3/non-DR4 in patients with latent autoimmune diabetes in adults from northern India.

Associations of HLA-DR3/DQ2 with GAD65 and DR4 with IA-2 antibodies in insulin-dependent diabetes mellitus (IDDM) and DR3/DQ2 with GAD65 antibodies in latent autoimmune diabetes in adult (LADA) patients are known. The aim of the present study was to look for association of HLA DR and DQ with GAD65, IA2 and ICA12 antibodies in IDDM (n = 97), LADA (n = 32), and malnutrition-modulated diabetes mellitus (MMDM) (n = 22) patients from northern India. HLA genotyping was done by the PCR-SSO method. Antibodies to GAD65, IA-2, and ICA-12 were assayed by radioimmunoassay using (35)S-labeled recombinant human GAD65, IA2, and ICA12 using the in vitro transcription-translation method. We found DR3 (29% vs. 11%) and DQ2 (36% vs. 14%) were increased in GAD65 antibody-positive compared to GAD65 antibody-negative IDDM patients (P > 0.05). ICA 12 antibodies were increased in either DR3 or DR4 (84% vs. 69%) positives compared to non-DR3/DR4 IDDM patients (P > 0.05). However in LADA patients, ICA12 was increased in non-DR3/DR4 patients compared to DR3- or DR4-positive patients (P < 0.05). In conclusion, in LADA patients, ICA 12 is associated with non-DR3/DR4 patients. No association between HLA and autoantibodies was seen in MMDM patients.

DR3 is associated with type 1 diabetes and blood group ABO incompatibility.

Type 1 diabetes is associated with autoimmunity against pancreatic beta cells. ABO incompatibility is associated with ABO immunization during pregnancy. Type 1 diabetes is associated with certain HLA DR and DQ haplotypes. The mechanism by which blood group incompatibility is associated with the risk of type 1 diabetes is not known. We propose that certain HLA alleles contribute to the development of both type 1 diabetes and ABO blood group incompatibility. We studied 57 children with ABO blood group incompatibility, 118 children with type 1 diabetes, and 98 age- and sex-matched unrelated healthy controls from Linköping. Typing of HLA DQA1, DQB1, and DRB1 was done on DNA extracted from peripheral blood, by PCR amplification, manual dot-blotting onto nylon membranes, synthetic sequence-specific oligonucleotide (SSO) probe 3' end-labeling with 32P-dCTP, and hybridization followed by stringency washes and autoradiography. We observed that DR3 allele was more frequent in patients with ABO incompatibility when compared to healthy controls (OR = 2.7, P(c) < 0.05). Patients with type 1 diabetes had significantly higher frequency of DR3, DQ2, DR4, and DQ8 alleles when compared to healthy controls. No significant difference was observed in frequency of DR3 between ABO blood group incompatibility and type 1 diabetes patients. We conclude that DR3 is associated with both the development of type 1 diabetes and ABO incompatibility.

Microsatellite allele 5 of MHC class I chain-related gene a increases the risk for insulin-dependent diabetes mellitus in latvians.

Insulin-dependent diabetes mellitus (IDDM) is one of the most common chronic diseases. It is an autoimmune, polygenic disease, associated with several genes on different chromosomes. The most important gene is human leukocyte antigen (HLA), also known as major histocompatibility complex (MHC), which is located on chromosome 6p21.3. HLA-DQ8/DR4 and DQ2/DR3 are positively associated with IDDM and DQ6 is negatively associated with IDDM in most Caucasian populations. The MICA gene is located in the MHC class I region and is expressed by monocytes, keratinocytes, and endothelial cells. Sequence determination of the MICA gene identifies 5 alleles with 4, 5, 6, and 9 repetitions of GCT or 5 repetitions of GCT with 1 additional insertion (GGCT), and the alleles are referred to as A4, A5, A5.1, A6, and A9. Analysis of allele distribution among 93 Latvian IDDM patients and 108 healthy controls showed that allele A5 of MICA is significantly increased in IDDM patients [33/93 (35%)] compared to healthy controls [22/108 (20%)] (OR = 2.15; P = 0.016). In conclusion, we believe that MICA may play an important role in the etiopathogenesis of IDDM.

MHC class I chain-related gene a alleles distinguish malnutrition-modulated diabetes, insulin-dependent diabetes, and non-insulin- dependent diabetes mellitus patients from eastern India.

Insulin-dependent diabetes mellitus (IDDM) is a polygenic disorder with an autoimmune basis for disease development. In addition to HLA, a second susceptibility locus for IDDM has been identified to lie in the major histocompatibility class III region. MIC-A is located in the MHC class III region and is expressed by monocytes, keratinocytes, and endothelial cells. Sequence determination of the MIC-A gene identifies trinucleotide repeat (GCT) microsatellite polymorphism in exon 5. Five alleles with 4, 5, 6, and 9 repetitions of GCT or 5 repetitions of GCT with 1 additional nucleotide insertion (GGCT) are identified. The alleles are A4, A5, A5.1, A6, and A9. The aim of our study was to find the association of MIC-A alleles with IDDM, malnutrition-modulated diabetes mellitus (MMDM), and non-insulin-dependent diabetes mellitus (NIDDM) patients. IDDM (n = 52), MMDM (n = 41), NIDDM (n = 212), and healthy controls (n = 73) from Cuttack, in eastern India, were studied. Of the 212 NIDDM patients analyzed, 96 of them were found to be positive for either GAD65 or IA-2 antibodies. Autoantibodies to GAD65 and IA-2 were measured by radioligand binding assay using (35)S-labeled recombinant human GAD65 and IA-2 in an in vitro transcription/translation system. Autoantibody-positive NIDDM patients (n = 96) and adult healthy controls for NIDDM (n = 113) were also compared. These autoantibody-positive NIDDM patients are considered as slow-onset IDDM or latent autoimmune diabetes in adults (LADA) patients. The samples were analyzed for MIC-A by PCR amplification, and fragment sizes were determined in an ABI prism DNA sequencer. The results of the MIC-A typing are: allele 9 of MIC-A is positively associated (OR 3.62; P < 0.001), and allele 4 is negatively associated (OR 0.31; P < 0.05) with MMDM patients compared to controls. Allele 5 is positively associated with IDDM (OR 2.64; P < 0.05) when compared to controls. Allele 5.1 is positively associated in the autoantibody-positive NIDDM patients compared to adult controls. Our findings of a significant increase of allele A9 in MMDM patients compared to healthy controls suggest that MMDM is immunogenetically different from IDDM in eastern India. MIC-A is important in the pathogenesis of MMDM patients from Cuttack. MIC-A alleles distinguish acute-onset IDDM from slow-onset IDDM, indicating that this molecule may be important for delaying the onset of IDDM with the result that these patients are diagnosed clinically as NIDDM.

Tumor necrosis factor-alpha allele 2 shows an association with insulin-dependent diabetes mellitus in Latvians.

Insulin-dependent diabetes mellitus (IDDM) is one of the most common chronic diseases. It is an autoimmune disease. Genes contributing the most for development of IDDM are located on chromosome 6p21.3 in the region called the major histocompatibility complex (MHC). HLA-DQ8/DR4 and DQ2/DR3 have shown positive association with IDDM, while DQ6 has negative association with IDDM in most Caucasian populations. The location of the tumor necrosis factor alpha (TNF-alpha) gene in the MHC suggests the role of TNF in the etiology of IDDM as an autoimmune disease. The TNF region contains several polymorphisms that are associated with different levels of TNF-alpha production and susceptibility to autoimmune and infectious diseases. Ninety-two Latvian IDDM patients corresponding to WHO diagnostic criteria and 107 unrelated age- and sex-matched healthy controls were analyzed for the frequency of TNF-alpha alleles to test the hypothesis that TNF-alpha is associated with IDDM. We found that TNF-alpha microsatellite allele 2 is associated with IDDM, 29/92 (32%), versus 14/107 (13%) in healthy controls. The test of the strongest association of the MICA A5 allele and TNF-alpha allele 2 with IDDM showed that both are independently associated with the disease.

Microsatellite allele A5.1 of MHC class I chain-related gene A is associated with latent autoimmune diabetes in adults in Latvia.

NIDDM is one of the most common forms of diabetes. The diagnosis is based on WHO classification, which is a clinical classification and misses the autoimmune diabetes in adults. Therefore, among the clinically diagnosed NIDDM cases, there can be a certain number of patients with latent autoimmune diabetes in adults (LADA). The MICA gene is located in the MHC class I region and is expressed by monocytes, keratinocytes, and endothelial cells. Sequence determination of the MICA gene identifies trinucleotide repeat (GCT) microsatellite polymorphism, which identifies 5 alleles with 4, 5, 6, and 9 repetitions of GCT (A4, A5, A6, and A9) or 5 repetitions of GCT with 1 additional G insertion for allele A5.1. From our previous studies, we have shown that microsatellite allele A5 of MICA is associated with IDDM. The aim of this study was to test the hypothesis that certain MICA alleles are associated with LADA among clinically diagnosed NIDDM. Out of 100 clinically diagnosed NIDDM patients, 49 tested positive for GAD65 and IA-2 antibodies by use of 35S RIA. Samples from these 49 patients and 96 healthy controls were analyzed for MICA by PCR amplification, and fragment sizes were determined in an ABI prism DNA sequencer. Our results show that MICA allele A5.1 is significantly increased in antibody-positive (GAD65 or IA-2) NIDDM patients [35/49 (72%)] when compared to healthy controls [22/96 (23%)] (OR = 8.4; P < 0.0001). However, we do not see any association with each of the antibodies separately. From our study, we conclude that (a) MICA allele A5.1 is associated with LADA and (b) MICA may play an important role in the etiopathogenesis of LADA.