Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, we describe the isolation, expression, and characterization of a new member of the transmembrane protein tyrosine phosphatase family from human brain, designated IA-2 beta. The 3853-bp cDNA encodes 986 amino acids with a molecular mass of 108,044 daltons (a predicted pI value of 5.8). The intracellular domain of human IA-2 beta is 74% identical to human IA-2. Northern blot analysis showed that IA-2 beta cDNA recognized two transcripts (approximately 5.0 kb and 4.0 kb) in four of five human insulinomas, one glucagonoma, and in normal human brain, pituitary, and pancreas, but not in a variety of other normal tissues. Rabbit antiserum, raised against the intracellular domain of IA-2 beta, reacted with pancreatic islets. Treatment of in vitro-translated full-length IA-2 beta protein with trypsin converted it into a 37-kD fragment. Using recombinant human IA-2 beta, we developed a radioimmunoprecipitation assay to measure autoantibodies in the sera of patients with insulin-dependent diabetes mellitus (IDDM). Seventy-six new-onset IDDM patients were tested. Thirty-seven percent (28 of 76) of the IDDM sera-but less than 1% of the control sera (1 of 174)-reacted with IA-2 beta. The same IDDM sera tested for autoantibodies to IA-2 and glutamic acid decarboxylase (GAD65) showed that 64% (49 of 76) and 57% (43 of 76), respectively, were positive. All but two of the IA-2 beta autoantibody-positive sera also reacted with IA-2, supporting the close sequence similarity between the two molecules. Combination of any two markers, such as IA-2 beta and IA-2, or IA-2 beta and GAD65, or IA-2 and GAD65, revealed that 67%, 74%, and 87% of IDDM sera were positive for autoantibodies, respectively. Blocking of IDDM sera with recombinant IA-2, IA-2 beta, or GAD65 resulted in marked inhibition of reactivity of IDDM sera with pancreatic islet sections as measured by islet cell autoantibody immunofluorescence. This result suggests that these three autoantigens are the major targets of islet-cell autoantibody reactivity.
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PMID:Autoantigens in insulin-dependent diabetes mellitus: molecular cloning and characterization of human IA-2 beta. 922 May 40

Islet antigens associated with type 1 diabetes include a recently identified protein tyrosine phosphatase-like molecule IA-2, which contains the intracellular fragment IA-2ic. To determine whether combinations of antibodies including those to IA-2 characterize and predict type 1 diabetes, we studied antibodies to IA-2, IA-2ic, glutamic acid decarboxylase (GAD65), and islet cell antibodies (ICAs) in 1) 60 newly diagnosed type 1 diabetic patients followed for 1 year, 2) 31 monozygotic twin pairs discordant for type 1 diabetes followed up to 12 years (11 twins developed diabetes), 3) 18 dizygotic twin pairs discordant for type 1 diabetes, and 4) normal healthy control subjects. Newly diagnosed type 1 diabetic patients frequently had antibodies to IA-2 (62%), IA-2ic (67%), GAD65 (77%), and ICAs (85%). The intracellular fragment of IA-2 probably contains the immunodominant epitope as 137 of 143 samples with IA-2 antibodies from type 1 diabetic patients also had IA-2ic antibodies. Monozygotic twins were usually discordant for antibody specificities. Concordance was higher in monozygotic than matched dizygotic twins for both antibody combinations (33 vs. 6%, P < 0.05) and the development of diabetes (33 vs. 0%, P < 0.01). In monozygotic twins, all the antibodies were highly predictive of type 1 diabetes (positive predictive values all >87%), although antibodies were also detected in twins at low risk of disease. In summary, IA-2 emerges as a major antigen associated with type 1 diabetes and distinct from GAD65. Type 1 diabetes-associated autoimmunity, which is probably induced by environmental factors, does not necessarily herald progression to the disease. However, genetic factors may influence the development of combinations of disease-associated antibodies and the progression to type 1 diabetes.
Diabetes 1997 Aug
PMID:Value of antibodies to islet protein tyrosine phosphatase-like molecule in predicting type 1 diabetes. 923 50

Presymptomatic autoantibody markers of insulin-dependent (Type 1) diabetes mellitus (IDDM) are less well characterized in adults than in children. We quantitated anti-GAD, anti-ICA512 and ICA by titration to endpoint and compared frequencies and levels in 139 Finnish women from whom 390 serum samples had been archived during antecedent pregnancies for 10 years before and up to 1 year after diagnosis of diabetes. Also, we compared the autoantibody status in adults with IDDM with that of children with newly diagnosed IDDM. Of the 35 women seropositive for 1 or more autoantibodies, 77% developed IDDM, 11% non-insulin-dependent (Type 2) diabetes mellitus (NIDDM), 9% gestational diabetes mellitus requiring insulin (GDM-ins) and 3% GDM controlled by diet. The frequency of antibodies during the 10-year presymptomatic period was 83% for anti-glutamic acid decarboxylase (GAD), 52% for anti-ICA512 and 41% for islet cell antibodies (ICA) for those who developed IDDM, 25%, 17%, and 0% for NIDDM, 12%, 4%, and 8% for GDM-ins and 1%, 0%, and 1% for GDM-diet. Anti-GAD was found most consistently in early samples; 13 of 15 with a single autoantibody at their first test had anti-GAD. Among those who developed IDDM, the frequency of anti-GAD was constant, anti-ICA512 increased threefold, and ICA increased slightly before diagnosis. Levels of the autoantibodies varied between subjects, but were relatively stable in individual subjects. Comparison of tests on the women, and children after diagnosis of IDDM, showed the frequencies and levels to be the same for anti-GAD but lower for anti-ICA512 and ICA in adults. Our observations show in women the long latency of seropositivity before overt IDDM, the predominance of anti-GAD among these three serological markers, and the presence of these markers in NIDDM presumably representing a NIDDM phase of autoimmune insulitis.
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PMID:Autoantibodies associated with presymptomatic insulin-dependent diabetes mellitus in women. 927 95

Women with gestational diabetes mellitus (GDM) have a considerable risk of developing diabetes later in life. To determine the predictive value of autoantibody markers in gestational diabetic pregnancy for the development of type 1 diabetes postpartum, we tested 437 patients with GDM (289 women treated with diet only [GDM-A] and 148 requiring insulin treatment during pregnancy [GDM-B]) for antibodies to islet cells (ICAs), GAD (GADAs), and tyrosine phosphatase ICA512/IA-2 (IA2As). We prospectively followed them with repeated oral glucose tolerance tests and antibody determinations for up to 7 years postpartum (mean, 1.6 years; range, 0-7.2 years). The cumulative risk of diabetes up to 5 years postpartum was 17% (95% CI 12-22%). The risk of type 1 diabetes was 3% (2-5%) by 9 months and 7% (4-9%) 2 years after delivery. At delivery, 8.5% of all patients were ICA+, 9.5% were GADA+, 6.2% were IA2A+, and 18.1% were positive for at least one antibody (12.6% for GDM-A vs. 30.4% for GDM-B, P < 0.0001). During follow-up, GADAs persisted in 75%, ICAs in 35%, and IA2As in 30% of the subjects positive for the respective marker at delivery. By 2 years postpartum, 29% (19-39%) of patients positive for at least one antibody developed type 1 diabetes, compared with 2% (1-4%) of antibody-negative patients (P < 0.0001). Thereby, the risk for type 1 diabetes 2 years postpartum increased with the number of antibodies present at delivery from 17% (6-28%) for one antibody, to 61% (30-91%) for two antibodies, and to 84% (55-100%) for 3 antibodies. Risk of progression to type 1 diabetes postpartum was also associated with the status of parity. Women with one or more pregnancies before the index pregnancy had a higher risk for type 1 diabetes 2 years after delivery (14.7% [4.9.-24.5%]) than women having their first (i.e., index) pregnancy (5% [2.9-7.1%]) (P < 0.006). A comparison of different prediction strategies showed that single antibody screening with GADA yielded the highest sensitivity of 63% (45-75%), compared with ICA (48% [31-65%]) and IA2A (34% [13-47%]). Combined screening with two autoantibodies increased sensitivity to 74% (58-90%) and 75% (60-92%) when using GADA plus ICA or GADA plus IA2A, respectively. Screening with all three markers improved sensitivity further to 82% (67-100%). Beta-cell autoantibodies determined at delivery in women with GDM are highly predictive for the development of type 1 diabetes postpartum. Autoantibody screening in pregnant women with GDM from populations at high risk for type 1 diabetes should therefore be considered to allow early diagnosis and appropriate therapy.
Diabetes 1997 Sep
PMID:Prediction of type 1 diabetes postpartum in patients with gestational diabetes mellitus by combined islet cell autoantibody screening: a prospective multicenter study. 928 47

IA-2 and IA-2 beta are major autoantigens in insulin-dependent diabetes mellitus (IDDM) and the precursors, respectively, of a 40-and 37-kDa tryptic fragment that reacts with IDDM sera. In the present study, by amino acid sequencing of recombinant IA-2 and IA-2 beta, we determined the tryptic cleavage sites involved in the generation of these fragments. Both cleavage sites are immediately after an arginine residue at position 653 for IA-2 and position 679 for IA-2 beta. The resulting tryptic fragments are 326 and 307 amino acids in length and retain their ability to react with IDDM sera. In contrast to IA-2 and IA-2 beta, other members of the protein tyrosine phosphatase (PTP) family (i.e., RPTP kappa, RPTPmu, NU-3, SHP, and 3CH134) are completely susceptible to digestion by trypsin. Sequence analysis revealed five conserved cysteine residues in IA-2 and IA-2 beta that are not present in other PTPs. Reduction and alkylation of IA-2 and IA-2 beta recombinant proteins resulted in loss of both resistance to digestion by trypsin and reactivity with autoantibodies in IDDM sera. It is concluded that disulfide bond formation plays a critical role in the maintenance of antigenic structure and that the autoantibodies to IA-2/IA-2 beta in IDDM sera recognize conformational epitopes.
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PMID:Autoantibodies to IA-2 and IA-2 beta in insulin-dependent diabetes mellitus recognize conformational epitopes: location of the 37- and 40-kDa fragments determined. 931 67

Nonobese diabetic (NOD) mice develop spontaneous insulin-dependent diabetes mellitus (IDDM), and the pancreas-infiltrating T cells invariably show a Th1 phenotype. We demonstrated here that the interleukin (IL)-12 antagonist (p40)2 can deviate the default Th1 development of naive T cell receptor (TCR)-transgenic CD4+ cells to the Th2 pathway in vitro. Although (p40)2 does not modify the cytokine profile of polarized Th1 cells, it prevents further recruitment of CD4- cells into the Th1 subset. To study the involvement of Th1 and Th2 cells in the initiation and progression of IDDM, we targeted endogenous IL-12 by administration of (p40)2 in NOD mice. (p40)2 administration to NOD mice inhibits interferon-gamma but not IL-10 production in response to lipopolysaccharide (LPS) or to the putative autoantigen IA-2. Serum immunoglobulin isotypes determined after (p40)2 treatment indicate an increase in Th2 and a decrease in Th1 helper activity. Administration of (p40)2 from 3 weeks of age onwards, before the onset of insulitis, results in the deviation of pancreas-infiltrating CD4+ but not CD8+ cells to the Th2 phenotype as well as in the reduction of spontaneous and cyclophosphamide-accelerated IDDM. After treating NOD mice with (p40)2 from 9 weeks of age, when insulitis is well established, few Th2 and a reduced percentage of Th1 cells are found in the pancreas. This is associated with a slightly decreased incidence of spontaneous IDDM, but no protection from cyclophosphamide-accelerated IDDM. In conclusion, deviation of pancreas-infiltrating CD4+ cells to Th2 is associated with protection from IDDM. However, targeting IL-12 after the onset of insulitis, when the pancreas contains polarized Th1 cells, is not sufficient to induce an effective immune deviation able to significantly modify the course of disease.
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PMID:Deviation of pancreas-infiltrating cells to Th2 by interleukin-12 antagonist administration inhibits autoimmune diabetes. 934 77

Sardinia and Finland have the highest incidence of insulin-dependent diabetes mellitus (IDDM) in the world. Therefore, both regions represent ideal observatories for investigating the environmental, genetic and immunological factors which have led to this dramatic increase. We have concentrated our efforts on Sardinia. Among several projects, there is the mapping of the island for hot and cold spots for overt IDDM. In order to map the island for pre-IDDM, we have collected and bled around 10,000 school children (age 6-14 years) and we are now in the process of enrolling around 30,000 new-born babies. We report here our initial results, which show that progression to IDDM is accompanied in both cohorts by the presence of a combination of islet-cell antibodies with either glutamic acid decarboxylase or IA-2 antibodies or both. This approach should lead to the design of reliable models of IDDM prediction in the general population, which will benefit an early insulin treatment and, hopefully, an effective prevention of the disease.
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PMID:Sardinia: a battlefield approach to type I diabetes epidemiology. Sardinia-IDDM Study Groups. 935 Apr 51

Insulin-dependent diabetes (IDD) is a chronic immune-endocrine disease in which there is a progressive destruction of insulin-secreting pancreatic beta cells, caused primarily by autoreactive T cells. Many islet cell proteins including insulin, glutamic acid decarboxylase, and tyrosine phosphatase antigens (IA-2) are targeted by the autoimmune responses in IDD patients. Since its discovery 75 years ago, insulin has been the major player in the clinical management of hyperglycaemia in these patients. The morbidity and mortality associated with IDD derives mainly from the complications of the disease. However, routine insulin injections seldom achieve a consistent, near-normal glucose level, where multiple daily doses of the hormone involve considerable restrictions to a normal lifestyle. In terms of economics, the management of diabetes is expensive, and in the USA diabetes alone accounts for one seventh of the healthcare budget. These clinical, lifestyle and economic issues emphasize the need to investigate alternative preventative measures in IDD treatment. Recent reports suggest a pivotal role for insulin in various aspects of the immune system. In this study, insulin and B-chain were used to modulate autoimmune responses in non-obese diabetic mice, findings which have therapeutic implications in man.
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PMID:Insulin in diabetes prevention. 935 Apr 52

Apart from genes in the HLA complex (IDDM1) and the variable number of tandem repeats in the 5' region of the insulin gene (INS VNTR, IDDM2), several other loci have been proposed to contribute to IDDM susceptibility. Recently, linkage and association have been shown between the cytotoxic T lymphocyte-associated protein 4 (CTLA-4) gene on chromosome 2q and IDDM. In a registry-based group of 525 recent-onset IDDM patients <40 years old we investigated the possible interactions of a CTLA-4 gene A-to-G transition polymorphism with age at clinical disease onset and with the presence or absence of established genetic (HLA-DQ, INS VNTR) and immune disease markers (autoantibodies against islet cell cytoplasm (ICA); insulin (IAA); glutamate decarboxylase (GAD65-Ab); IA-2 protein tyrosine phosphatase (IA-2-Ab)) determined within the first week of insulin treatment. In new-onset IDDM patients. G-allele-containing CTLA-4 genotypes (relative risk (RR)= 1.5; 95% confidence interval (CI) = 1.2-2.0; P < 0.005) were not preferentially associated with age at clinical presentation or with the presence of other genetic (HLA-DR3 or DR4 alleles; HLA-DQA1*0301-DQB1*0302 and/or DQA1*0501-DQB1*0201 risk haplotypes; INS VNTR I/I risk genotype) or immune (ICA, IAA, IA-2-Ab, GAD65-Ab) markers of diabetes. For 151 patients, thyrogastric autoantibodies (anti-thyroid peroxidase, anti-thyroid-stimulating hormone (TSH) receptor, anti-parietal cell, anti-intrinsic factor) were determined, but association between CTLA-4 risk genotypes and markers of polyendocrine autoimmunity could not be demonstrated before or after stratification for HLA- or INS-linked risk. In conclusion, the presence of a G-containing CTLA-4 genotype confers a moderate but significant RR for IDDM that is independent of age and genetic or immune disease markers.
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PMID:CTLA-4 gene polymorphism confers susceptibility to insulin-dependent diabetes mellitus (IDDM) independently from age and from other genetic or immune disease markers. The Belgian Diabetes Registry. 935 55

Strategies for assessing risk of progression to IDDM, based on single and combined autoantibody measurement, were evaluated in 2,855 schoolchildren (median age 11.4 years) and 256 children with newly diagnosed IDDM (median age 10.2 years), recruited to a population-based study in the Oxford region. In 256 children with IDDM, levels of antibodies > or =97.5th centile of the schoolchild population were found in 225 (88%) for islet cell antibodies (ICAs), in 190 (74%) for antibodies to GAD, in 193 (75%) for antibodies to protein tyrosine phosphatase IA-2 (IA-2), and in 177 (69%) for autoantibodies to insulin (IAAs). Estimates of risk of progression to IDDM within 10 years, derived by comparing the distribution of antibody markers in the two populations (schoolchildren and children with IDDM), were 6.7% (ICAs), 6.6% (GAD antibodies), 5.6% (IA-2 antibodies), and 4.8% (IAAs) for schoolchildren with levels above the 97.5th centile, increasing to 20, 23, 24, and 11%, respectively, for antibody levels >99.5th centile. Most children with IDDM had multiple antibody markers, and 89% of those diagnosed over age 10 years had > or =2 antibodies above the 97.5th centile, as compared against 0.7% of schoolchildren, in whom this combination gave a 27% 10-year estimated risk of IDDM. Risk increased but sensitivity fell as combined antibody thresholds were raised, or the number of antibodies above the threshold was increased. Strategies based on detection of > or =2 antibodies with primary testing for GAD and IA-2 antibodies and second line testing for ICAs and/or IAAs were evaluated. Detection of at least two markers selected from GAD antibodies > or =97.5th centile and/or IA-2 antibodies > or =99.5th centile and/or ICAs > or =97.5th centile identified 0.25% of schoolchildren and 83% of children with newly diagnosed IDDM, with an estimated risk of 71% (95% CI 57-91). Although confirmation from prospective studies is still needed, this analysis suggests that antibody combinations can predict diabetes in the general population.
Diabetes 1997 Nov
PMID:Prediction of IDDM in the general population: strategies based on combinations of autoantibody markers. 935 15


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