Insulinoma-associated Protein 2 Research Articles

The expression of GADA, ZnT8A and IA-2A in patients with type 1 diabetes mellitus with thyroid disease and their correlation with thyroid autoantibodies.

The aim of this research was to study the expression of anti-glutamate decarboxylase antibody (GADA), zinc transporter-8 autoantibody (ZnT8A), and insulinoma-associated protein-2 antibody (IA-2A) in patients with type 1 diabetes (T1DM) with thyroid disease (TD) and its correlation with thyroid autoantibodies. 380 patients with T1DM were included in the study, of which 313 patients with T1DM alone were included in the control group. In the TD group, 41 patients with T1DM and Hashimoto's thyroiditis (HT) were included, and 26 cases of T1DM patients with Graves' disease were included in the Graves group. The clinical features of the control group, the HT group, and the Graves group were compared. The positive rates of insulin autoantibodies in the control group and the TD group were analyzed. The clinical characteristics of patients with and without insulin autoantibody positivity were compared. The positive rates of thyroid autoantibodies in T1DM patients with positive GADA, ZnT8A, IA-2A, and different numbers of positive insulin autoantibodies were analyzed. The levels of total cholesterol (TC) and thyroid stimulating hormone (TSH) in the HT group were significantly higher than those in the control and Graves groups, and the levels of free thyroid hormone (FT4) and low-density lipoprotein cholesterol (LDL-C) were significantly lower than those in the control and Graves groups (p<0.001). The levels of TC and TSH in the Graves group were significantly lower than those in the control group, the levels of HbA1c, LDL-C, and FT4 were significantly higher than those in the control group, and the levels of FT3 were significantly higher than those in the control and HT groups (p<0.001). The levels of C peptide, triglyceride (TG), and LDL-C of insulin autoantibodies positive patients were significantly lower than those of negative patients (p<0.05). The positive rates of GADA, ZnT8A, and IA-2A in the TD group, as well as the positive rates of double antibodies and triple antibodies, were significantly higher than those of the control group (p<0.05). In T1DM patients, the positive rates of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) in GADA and IA-2A-positive patients were significantly higher than those in GADA and IA-2A-negative patients (p<0.05). The positive rate of TPOAb in ZnT8A-positive patients was significantly higher than that in ZnT8A-negative patients (p<0.05). The positive rates of TRAb, TPOAb, and TGAb in T1DM patients positive for two of the three insulin autoantibodies and three insulin autoantibodies were significantly higher than those positive for one of the three insulin autoantibodies (p<0.001). TD can exacerbate the disorder of glucose and lipid metabolism in patients with T1DM, and multiple insulin autoantibodies positive T1DM patients it is more likely to have thyroid autoantibody positivity. It is suggested that patients with aggravated glucose and lipid metabolism and multiple insulin autoantibody positivity should be routinely screened for thyroid antibodies to help early diagnosis of TD.

Production and antigenicity analysis of a recombinant insulinoma associated protein-2 in HEK293 cells

Insulinoma-associated protein-2 (IA-2) is a transmembrane glycoprotein belonging to the tyrosine phosphatase-like protein family as well as an important autoantigen in the diagnosis of type 1 diabetes. IA-2 products have been marketed in Europe and the United States. At present, commercially available IA-2 antigens are either the recombinant IA-2ic domain or the IA-2 naturally extracted from bovine islets. However, the recombinant IA-2 antigen displays weak positive in clinic practice, which often results in occasional detection failures, thus cannot completely replace the naturally extracted IA-2 antigen. In this study, an HEK293 expression system was used to explore the production of recombinant IA-2. An IA-2 transmembrane fragment (IA-2 TMF) located at amino acid position 449-979, also known as the natural membrane protein form of IA-2, was produced in HEK293 through transfection, and both the expression conditions and dissolution conditions of the membrane protein were also optimized. The purified membrane protein yield was 0.78 mg/L cell culture. Subsequently, the antigen activity of IA-2 TMF was compared with RSR rhIA-2 through enzyme linked immunosorbent assay. The serum of 77 type 1 diabetes patients and 32 healthy volunteers were detected. Receiver operating characteristic curve (ROC) curve was used to characterize the sensitivity and specificity of the test results. The results showed that the sensitivity of IA-2 TMF was 71.4% (55/77), while the sensitivity of RSR rhIA-2 was 63.6% (49/77), and the specificity of both antigens were all 100%. There was no significant difference in specificity between the two antigens, but the sensitivity of IA-2 TMF was appreciably better than that of the imported gold standard RSR rhIA-2 antigen. In conclusion, the recombinant IA-2 TMF produced in HEK293 cells can be used as a raw material to develop in vitro diagnostic reagents for type 1 diabetes.

ODP166 Autoantibody Positivity and Random C-peptide Profile in Young Ethnic South Indian Population with Diabetes Mellitus

Abstract The islet cell autoantibody and beta-cell reserve profiles of young-onset diabetes patients in India are not only heterogeneous but also differ from those in the rest of the world. We sought to assess 3 standard islet cell autoantibodies and random C-peptide in the young ethnic South Indian population with diabetes mellitus attending the Endocrinology OPD of our tertiary care. A total of 190 young diabetes patients aged between 12-30 years were screened for inclusion in the study. Known cases of gestational diabetes and those on diabetogenic drugs were excluded. Additionally, those with clinical features suggestive of pancreatic diabetes or maturity-onset diabetes of young (MODY), or any diabetes-associated syndromic disorders were also excluded. Finally, 138 eligible young diabetes patients were included in the study. The islet cell autoantibodies against glutamic acid decarboxylase (GAD), insulinoma-associated protein-2 (IA-2), zinc transporter (ZnT8)was measured by sandwich ELISA technique using a human GAD ELISA kit (Euroimmun, Germany), human IA2 ELISA kit (Euroimmun, Germany), human ZnT8 ELISA kit (RSR diagnostics, USA) respectively. Random C-peptide was measured with chemiluminescence immunoassay analyser Advia Centaur XP. Diagnosis of T1DM was based on the requirement of immediate insulin replacement therapy for hyperglycemia with or without acute-onset ketosis with random C-peptide (&amp;lt;0.6 ng/ml) with /without any of islet cell antibodies. Diagnosis of T2DM is based on the history of control of hyperglycemia with oral hypoglycemic agents with documentation of adequate beta-cell reserve (random C-peptide ≥ 0.6 ng/ml) while maintaining euglycemia. Based on the patient characteristics, treatment profile, islet cell antibody status, and beta-cell reserve as assessed by random C-peptide levels, 82 were classified as T1DM, and 48 were classified as T2DM. The rest 8 patients were categorized as unclassified diabetes. GAD antibody was seen in 54(66%) of 82 T1DM patients. Islet cell autoantibody negativity was documented in 21(26%) of T1DM patients. IA-2 and ZnT8 antibodies contributed to an additional 7(8%) to islet cell antibody positivity in T1DM patients. IA-2 antibody positivity was low and random C-peptide was undetectable in many cases of T1DM in our study and is probably due to prolonged duration of diabetes in many T1DM patients. Autoantibody positivity was seen in 4(8%) T2DM patients. These patients need to be followed up for possible evolution of latent autoimmune diabetes in adults.

Type 1 diabetes-related autoimmune antibodies in women with gestational diabetes mellitus and the long-term risk for glucose intolerance.

AimsTo characterize women with gestational diabetes mellitus (GDM) positive for type 1 diabetes-related autoimmune antibodies (T1D-related autoantibodies) in pregnancy and to evaluate their risk for long-term glucose intolerance.MethodsIn a multi-centric prospective cohort study with 1843 women receiving universal screening for GDM with a 75 g oral glucose tolerance test (OGTT), autoantibodies were measured in women with GDM: insulin autoantibodies (IAA), islet cell antibodies (ICA), insulinoma-associated protein-2 antibodies (IA-2A) and glutamic acid decarboxylase antibodies (GADA). Long-term follow-up ( ± 4.6 years after delivery) with a 75 g OGTT and re-measurement of autoantibodies was done in women with a history of GDM and autoantibody positivity in pregnancy.ResultsOf all women with GDM (231), 80.5% (186) received autoantibody measurement at a mean of 26.2 weeks in pregnancy, of which 8.1% (15) had one positive antibody (seven with IAA, two with ICA, four with IA-2A and two with GADA). Characteristics in pregnancy were similar but compared to women without autoantibodies, women with autoantibodies had more often gestational hypertension [33.3% (5) vs. 1.7% (3), p<0.001] and more often neonatal hypoglycemia [40.0% (6) vs. 12.5% (19), p=0.012]. Among 14 of the 15 autoantibody positive women with an early postpartum OGTT, two had impaired fasting glucose (IFG). Of the 12 women with long-term follow-up data, four tested again positive for T1D-related autoantibodies (three positive for IA-2A and one positive for ICA and IAA). Five women were glucose intolerant at the long-term follow-up of which two had IA-2A (one had IFG and one had T1D) and three without autoantibodies. There were no significant differences in long-term characteristics between women with and without autoantibodies postpartum.ConclusionsSystematic screening for T1D-related autoantibodies in GDM does not seem warranted since the low positivity rate for autoantibodies in pregnancy and postpartum. At 4.6 years postpartum, five out of 12 women were glucose intolerant but only two still had autoantibodies. In women with clinically significant increased autoantibody levels during pregnancy, postpartum autoantibody re-measurement seems useful since the high risk for further increase of autoantibody levels.

The Shape of the Oral Glucose Tolerance Test-Glucose Response Curve in Islet Cell Antibody-Positive vs. -Negative Obese Youth Clinically Diagnosed with Type 2 Diabetes.

BackgroundThe oral glucose tolerance test (OGTT)-glucose response curves (GRCs; incessant increase, monophasic, and biphasic) reflect insulin sensitivity and β-cell function, being worse in the former and superior in the latter. Here, we examined if the OGTT-GRC pattern is worse in obese antibody (glutamic acid decarboxylase 65-kDa [GAD65] and insulinoma-associated protein-2 [IA-2])-positive (Ab+) vs. –negative (Ab–) youth clinically diagnosed with type 2 diabetes (CDX-T2D).MethodsForty-seven obese youth, 15 Ab+ and 32 Ab–, were divided into three OGTT-GRC groups: incessant increase, monophasic, and biphasic. The prevalence of OGTT-GRC, clamp-measured insulin sensitivity, and β-cell function was compared.ResultsIncessant increase OGTT-GRC is the most frequent curve type and is three-fold higher in Ab+ vs. Ab– youth CDX-T2D. In Ab+ youth, there was up to 40% lower second-phase insulin secretion in the incessant increase group vs. the other two groups combined (monophasic and biphasic). In Ab– youth, while first- and second-phase insulin secretion was significantly lower in the incessant increase vs. the other two groups combined, overall β-cell function was less impaired than in Ab+ youth. In neither Ab– or Ab+ youth was OGTT-GRC related to hepatic or peripheral insulin sensitivity.ConclusionSevere insulin deficiency, a characteristic of type 1 diabetes, seems to be related to higher prevalence of incessant increase in Ab+ vs. Ab– obese youth.

Clinical features, biochemistry, and HLA-DRB1 status in youth-onset type 1 diabetes in Sudan.

To further understand clinical and biochemical features, and HLA-DRB1 genotypes, in new cases of diabetes in Sudanese children and adolescents. Demographic characteristics, clinical information, and biochemical parameters (blood glucose, HbA1c, C-peptide, autoantibodies against glutamic acid decarboxylase 65 [GADA] and insulinoma-associated protein-2 [IA-2A], and HLA-DRB1) were assessed in 99 individuals <18 years, recently (<18 months) clinically diagnosed with T1D. HLA-DRB1 genotypes for 56 of these Arab individuals with T1D were compared to a mixed control group of 198 healthy Arab (75%) and African (25%) individuals without T1D. Mean ± SD age at diagnosis was 10.1 ± 4.3 years (range 0.7-17.6 years) with mode at 9-12 years. A female preponderance was observed. Fifty-two individuals (55.3%) presented in diabetic ketoacidosis (DKA). Mean ± SD serum fasting C-peptide values were 0.22 ± 0.25 nmol/L (0.66±0.74 ng/ml). 31.3% were autoantibody negative, 53.4% were GADA positive, 27.2% were IA-2A positive, with 12.1% positive for both autoantibodies. Association analysis compared to 198 controls of similar ethnic origin revealed strong locus association with HLA-DRB1 (p < 2.4 × 10-14 ). Five HLA-DRB1 alleles exhibited significant T1D association: three alleles (DRB1*03:01, DRB1*04:02, and DRB1*04:05) were positively associated, while three (DRB1*10:01, DRB1*15:02, and DRB1*15:03) were protective. DRB1*03:01 had the strongest association (odds ratio=5.04, p=1.7 × 10-10 ). Young Sudanese individuals with T1D generally have similar characteristics to reported European-origin T1D populations. However, they have higher rates of DKA and slightly lower autoantibody rates than reported European-origin populations, and a particularly strong association with HLA-DRB1*03:01.

Genetic Composition and Autoantibody Titers Model the Probability of Detecting C-Peptide Following Type 1 Diabetes Diagnosis.

We and others previously demonstrated that a type 1 diabetes genetic risk score (GRS) improves the ability to predict disease progression and onset in at-risk subjects with islet autoantibodies. Here, we hypothesized that GRS and islet autoantibodies, combined with age at onset and disease duration, could serve as markers of residual β-cell function following type 1 diabetes diagnosis. Generalized estimating equations were used to investigate whether GRS along with insulinoma-associated protein-2 autoantibody (IA–2A), zinc transporter 8 autoantibody (ZnT8A), and GAD autoantibody (GADA) titers were predictive of C-peptide detection in a largely cross-sectional cohort of 401 subjects with type 1 diabetes (median duration 4.5 years [range 0–60]). Indeed, a combined model with incorporation of disease duration, age at onset, GRS, and titers of IA–2A, ZnT8A, and GADA provided superior capacity to predict C-peptide detection (quasi-likelihood information criterion [QIC] = 334.6) compared with the capacity of disease duration, age at onset, and GRS as the sole parameters (QIC = 359.2). These findings support the need for longitudinal validation of our combinatorial model. The ability to project the rate and extent of decline in residual C-peptide production for individuals with type 1 diabetes could critically inform enrollment and benchmarking for clinical trials where investigators are seeking to preserve or restore endogenous β-cell function.

Evaluation for type 1 diabetes associated autoantibodies in diabetic and non-diabetic Australian terriers and Samoyeds

BackgroundEvidence for an autoimmune etiology in canine diabetes is inconsistent and could vary based on breed. Previous studies demonstrated that small percentages of diabetic dogs possess autoantibodies to antigens known to be important in human type 1 diabetes, but most efforts involved analysis of a wide variety of breeds. The objective of this study was to evaluate the presence of glutamic acid decarboxylase 65 (GAD65), insulinoma-associated protein 2 (IA-2), and zinc transporter 8 (ZnT8) autoantibodies in diabetic and non-diabetic Australian Terriers and Samoyeds, two breeds with comparatively high prevalence of diabetes, in the United States.ResultsThere was no significant difference in the proportion of samples considered positive for GAD65 or ZnT8 autoantibodies in either breed evaluated, or for IA-2 autoantibodies in Australian Terriers (p > 0.05). The proportion of IA-2 autoantibody positive samples was significantly higher in diabetic versus non-diabetic Samoyeds (p = 0.003), but substantial overlap was present between diabetic and non-diabetic groups.ConclusionsThe present study does not support GAD65, IA-2, or ZnT8 autoantibodies as markers of autoimmunity in canine diabetes in Samoyeds or Australian Terriers as measured using human antigen sandwich enzyme-linked immunosorbent (ELISA) assays. Future studies using canine specific assays as well as investigation for alternative markers of autoimmunity in these and other canine breeds are warranted.

Decreased HLA-DQ expression on peripheral blood cells in children with varying number of beta cell autoantibodies

The risk for type 1 diabetes is strongly associated with HLA-DQ and the appearance of beta cell autoantibodies against either insulin, glutamate decarboxylase (GAD65), insulinoma-associated protein-2 (IA-2), or zinc transporter 8 (ZnT8). Prolonged exposure to autoantibodies may be related to T cell exhaustion known to occur in chronic infections or autoimmune disorders. It was hypothesized that autoantibody exposure may affect HLA-DQ expression on peripheral blood cells and thereby contribute to T cell exhaustion thought to be associated with the pathogenesis of type 1 diabetes. The aim of this study was to determine whether autoantibody exposure as an expression of autoimmunity burden was related to peripheral blood cell HLA-DQ cell surface expression in either 1) a cross-sectional analysis or 2) cumulative as area under the trajectory of autoantibodies during long term follow-up in the Diabetes Prediction in Skåne (DiPiS) study. Children (n = 67), aged 10–15 years were analyzed for complete blood count, HLA-DQ cell surface median fluorescence intensity (MFI), autoantibody frequency, and HLA genotypes by Next Generation Sequencing. Decreased HLA-DQ cell surface MFI with an increasing number of autoantibodies was observed in CD16+, CD14+CD16−, CD4+ and CD8+ cells but not in CD19+ cells and neutrophils. HLA-DQ cell surface MFI was associated with HLA-DQ2/8 in CD4+ T cells, marginally in CD14+CD16− monocytes and CD8+ T cells. These associations appeared to be related to autoimmunity burden. The results suggest that HLA-DQ cell surface expression was related to HLA and autoimmunity burden.

Clinical manifestation and islet β-cell function of a subtype of latent autoimmune diabetes in adults (LADA): positive for T cell responses in phenotypic type 2 diabetes.

To investigate the possibility of identifying a subtype of latent autoimmune diabetes in adults (LADA), T-LADA (T cell responses-positive and autoantibody-negative) from patients with phenotypic type 2 diabetes (T2D) by enzyme-linked immunospot (ELISPOT). Eighty-two patients with phenotypic T2D were studied. Autoantibodies against glutamic acid decarboxylase (GAD), insulinoma-associated protein-2 and zinc transporter 8 were measured by radioligand assay. Thirty-nine Ab+ and 43 Ab- patients with phenotypic T2D were enrolled for T cell assay of responses to GAD65 and C-peptide antigen by ELISPOT. (1) Eleven of 43 Ab- participants with phenotypic T2D were demonstrated interferon (IFN)-γ secreting T cells by ELISPOT, while 13 of 39 Ab+ patients with phenotypic T2D were positive for T cells responses to islet antigens. (2) The onset ages of T cell+ people with phenotypic T2D were younger than that of T cell- individuals (42.7 ± 9.3 vs. 48.2 ± 10.2years, P = 0.025). Moreover, T cell+ patients with T2D displayed a significantly lower fasting C-peptide (FCP) compared with T cell- participants [0.28 (0.02-0.84) vs. 0.42 (0.05-1.26) nmol/L, P = 0.013]. (3) Ab-T+ group had a significantly lower FCP compared with Ab-T- group [0.31 (0.13-0.84) vs. 0.51 (0.07-1.26) nmol/L, P = 0.023]. By measuring T cell responses to islet antigens in patients with phenotypic T2D, we identified a specific subtype of LADA who may be associated with worse basal β-cell function than classic T2D (Ab-T-).

The Evolving Landscape of Autoantigen Discovery and Characterization in Type 1 Diabetes.

Type 1 diabetes (T1D) is an autoimmune disease that is caused, in part, by T cell–mediated destruction of insulin-producing β-cells. High risk for disease, in those with genetic susceptibility, is predicted by the presence of two or more autoantibodies against insulin, the 65-kDa form of glutamic acid decarboxylase (GAD65), insulinoma-associated protein 2 (IA-2), and zinc transporter 8 (ZnT8). Despite this knowledge, we still do not know what leads to the breakdown of tolerance to these autoantigens, and we have an incomplete understanding of T1D etiology and pathophysiology. Several new autoantibodies have recently been discovered using innovative technologies, but neither their potential utility in monitoring disease development and treatment nor their role in the pathophysiology and etiology of T1D has been explored. Moreover, neoantigen generation (through posttranslational modification, the formation of hybrid peptides containing two distinct regions of an antigen or antigens, alternative open reading frame usage, and translation of RNA splicing variants) has been reported, and autoreactive T cells that target these neoantigens have been identified. Collectively, these new studies provide a conceptual framework to understand the breakdown of self-tolerance, if such modifications occur in a tissue- or disease-specific context. A recent workshop sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases brought together investigators who are using new methods and technologies to identify autoantigens and characterize immune responses toward these proteins. Researchers with diverse expertise shared ideas and identified resources to accelerate antigen discovery and the detection of autoimmune responses in T1D. The application of this knowledge will direct strategies for the identification of improved biomarkers for disease progression and treatment response monitoring and, ultimately, will form the foundation for novel antigen-specific therapeutics. This Perspective highlights the key issues that were addressed at the workshop and identifies areas for future investigation.

Prevalence of diabetes and presence of autoantibodies against zinc transporter 8 and glutamic decarboxylase at diagnosis and at follow up of Graves\u2019 disease

PurposeThe aim of this work was to investigate, in patients with newly diagnosed Graves’ disease (GD), the frequency of islet autoantibodies including autoantibodies against Zink transporter 8 (ZnT8A), as well as to investigate the relation between thyroid autoantibodies, islet autoantibodies and diabetes both before GD diagnosis and at follow-up.MethodsBlood samples from 278 patients with newly diagnosed GD were analyzed for autoantibodies against glutamic acid decarboxylase (GADA), insulinoma-associated protein-2 (IA2-A), three variants of zinc transporter 8 (ZnT8A), thyroid peroxidase (TPOA) and the TSH receptor (TRAb). Information on other autoimmune diseases, as well as development of diabetes during follow up was gathered from patient’s medical journal.ResultsAt GD diagnosis, 13.7% were positive for islet autoantibodies, with the majority being positive for GADA (8.7%) and ZnT8A (7.6%). TPOA were found positive in 71% and TRAb in 83%. No association was found between islet autoantibodies and thyroid autoantibodies or diabetes diagnosis during follow up. Positive association was found between islet autoantibodies and all forms of diabetes, diagnosed both before and after GD (OR: 2.5, CI: 1.1–6.8, p = 0.03) but not to other autoimmune diseases at GD diagnosis.ConclusionsThe incidence of GADA and ZnT8A in patients with GD is high and might indicate wide range endocrine autoimmunity, as well as risk for non-autoimmune diabetes rather than exclusively mark beta cell autoimmunity and type 1 diabetes.

Childhood thyroid autoimmunity and relation to islet autoantibodies in children at risk for type 1 diabetes in the diabetes prediction in skåne (DiPiS) study

Background: The aim was to determine prevalence and age at seroconversion of thyroid autoimmunity in relation to islet autoantibodies, gender and HLA-DQ genotypes in children with increased risk for type 1 diabetes followed from birth.Methods: In 10-year-old children (n = 1874), blood samples were analysed for autoantibodies against thyroid peroxidase (TPOAb), thyroglobulin (TGAb), glutamic acid decarboxylase 65 (GADA), Zink transporter 8 (ZnT8R/W/QA), insulinoma-associated protein-2 (IA-2A), insulin (IAA) and HLA-DQ genotypes. Prospectively collected samples from 2 years of age were next analysed for TPOAb, and TGAb and, finally, in confirming samples at 11–16 years of age along with TSH and FT4. Frequencies were tested with Chi-square or Fischer’s exact tests, autoantibody levels with Wilcoxon and correlations between autoantibody levels with Spearman’s rank correlation test.Results: The prevalence of thyroid autoimmunity was 6.9%, overrepresented in girls (p < .001) also having higher TPOAb levels at 10 years (p = .049). TPOAb was associated with GADA (p = .002), ZnT8R/W/QA (p = .001) and IA-2A (p = .001) while TGAb were associated with ZnT8R/W/QA (p = .021). In boys only, TPOAb were associated with GADA (p = .002), IA-2A (p = .001), ZnT8R/W/QA (p = .001) and IAA (p = .009), and TGAb with GADA (p = .013), IA-2A (p = .005) and ZnT8R/W/QA (p = .003). Levels of IA-2A correlated to both TPOAb (p = .021) and to TGAb (p = .011). In boys only, levels of GADA and TGAb correlated (p = .009 as did levels of IA-2A and TPOAb (p = .013). The frequency and levels of thyroid autoantibodies increased with age. At follow-up, 22.3% had abnormal thyroid function or were treated with thyroxine.Conclusions: Thyroid autoimmunity and high TPOAb levels were more common in girls. In contrast, in boys only, there was a strong association with as well as correlation between levels of thyroid and islet autoantibodies. It is concluded that while girls may develop autoimmune thyroid disease (AITD) independent of islet autoantibodies, the risk for thyroid disease in boys may be linked to concomitant islet autoimmunity.

Thyroid and Islet Autoantibodies Predict Autoimmune Thyroid Disease at Type 1 Diabetes Diagnosis.

Screening of autoimmune thyroid disease in children with type 1 diabetes is important but varies between clinics. To determine the predictive value of thyroid autoantibodies, thyroid function, islet autoantibodies, and HLA-DQ at diagnosis of type 1 diabetes for autoimmune thyroid disease during follow-up. Forty-three Swedish pediatric endocrinology units. At diagnosis of type 1 diabetes, autoantibodies against thyroid peroxidase (TPOAb), thyroglobulin (TGAb), glutamic acid decarboxylase (GADA), insulin, insulinoma-associated protein-2, and 3 variants of zinc transporter 8 (ZnT8W/R/QA) HLA-DQA1-B1 genotypes and thyroid function were analyzed in 2433 children. After 5.1 to 9.5 years, information on thyroxine treatment was gathered from the Swedish National Board of Health and Welfare's Prescribed Drug Register. Thyroxine was prescribed to 6% of patients. In patients <5 years of age, female sex [hazard ratio (HR) = 4.60; P = 0.008] and GADA (HR = 5.80; P = 0.02) were predictors. In patients 5 to 10 years old, TPOAb (HR = 20.56; P < 0.0001), TGAb (HR = 3.40; P = 0.006), and thyroid-stimulating hormone (TSH) (HR = 3.64; P < 0.001) were predictors, whereas in 10 to 15 year olds, TPOAb (HR = 17.00; P < 0.001) and TSH (HR = 4.11; P < 0.001) predicted thyroxine prescription. In addition to TPOAb and TSH, GADA at diagnosis of type 1 diabetes is important for the prediction of autoimmune thyroid disease in children <5 years of age.

Validation of a rapid type 1 diabetes autoantibody screening assay for community-based screening of organ donors to identify subjects at increased risk for the disease.

The Network for Pancreatic Organ donors with Diabetes (nPOD) programme was developed in response to an unmet research need for human pancreatic tissue obtained from individuals with type 1 diabetes mellitus and people at increased risk [i.e. autoantibody (AAb)-positive] for the disease. This necessitated the establishment of a type 1 diabetes-specific AAb screening platform for organ procurement organizations (OPOs). Assay protocols for commercially available enzyme-linked immunosorbent assays (elisas) determining AAb against glutamic acid decarboxylase (GADA), insulinoma-associated protein-2 (IA-2A) and zinc transporter-8 (ZnT8A) were modified to identify AAb-positive donors within strict time requirements associated with organ donation programmes. These rapid elisas were evaluated by the international islet AAb standardization programme (IASP) and used by OPO laboratories as an adjunct to routine serological tests evaluating donors for organ transplantation. The rapid elisas performed well in three IASPs (2011, 2013, 2015) with 98-100% specificity for all three assays, including sensitivities of 64-82% (GADA), 60-64% (IA-2A) and 62-68% (ZnT8A). Since 2009, nPOD has screened 4442 organ donors by rapid elisa; 250 (5·6%) were identified as positive for one AAb and 14 (0.3%) for multiple AAb with 20 of these cases received by nPOD for follow-up studies (14 GADA+, two IA-2A(+) , four multiple AAb-positive). Rapid screening for type 1 diabetes-associated AAb in organ donors is feasible, allowing for identification of non-diabetic, high-risk individuals and procurement of valuable tissues for natural history studies of this disease.

Cord blood insulinoma-associated protein 2 autoantibodies are associated with increased risk of type 1 diabetes in the population-based Diabetes Prediction in Skåne study.

The aim of this study was to examine the effect of cord blood autoantibodies on the risk for type 1 diabetes in children followed prospectively from birth. The Diabetes Prediction in Skåne (DiPiS) study consists of 35,853 children from the general population born during 2000-2004. Samples were collected at birth and analysed for HLA genotypes and autoantibodies to glutamate decarboxylase 65 (GAD65), insulin and insulinoma-associated protein 2 (IA-2). After adjusting for HLA, sex, maternal age and parental type 1 diabetes, independent associations with risk of diabetes were assessed using multivariate Cox proportional hazards models. In total, 151 children (0.4%) had developed type 1 diabetes by the end of 2013 at a median age of 5.8 years (0.8-12.2 years). In the multivariate analysis, the presence of IA-2 autoantibodies (IA-2A) in cord blood (HR 6.88, 95% CI 1.46,32.4; p = 0.003), but not maternal diabetes (HR 1.38, 95% CI 0.24,7.84; p = 0.71), was associated with risk of developing type 1 diabetes. No increased risk could be seen for the presence of autoantibodies to GAD65 or insulin. Our study indicates that the presence of cord blood IA-2A superimposes maternal diabetes and other cord blood islet autoantibodies as a predictor of type 1 diabetes development in the child. These findings may be of significance for future screening and study protocols on type 1 diabetes prediction.

Neuropeptide Y is a minor autoantigen in newly diagnosed type 1 diabetes patients

Autoantibodies (A) against Neuropeptide Y (NPY), was reported in 9% newly diagnosed type 1 diabetes (T1D) patients. A single nucleotide polymorphism (SNP) at rs16139 (T1128C) within the NPY-gene identified an amino acid substitution from leucine (L) to proline (P) (L7P) associated with both glucose tolerance and type 2 diabetes. We aimed to determine: (i) the influence of autoantibodies to leucine neuropeptide Y (NPY-LA) and autoantibodies to proline neuropeptide Y (NPY-PA) on the diagnostic sensitivity of type 1 diabetes (T1D), (ii) the association of NPYA with major islet autoantibodies, and (iii) the association of NPYA with HLA-DQ genotypes in newly diagnosed T1D patients. Serum from the HLA-DQ typed T1D patients (n = 673; median age 10 yr) from Skåne, Sweden, were analyzed for autoantibodies against NPY-L and NPY-P in a radioligand binding assay, and against glutamic acid decarboxylase 65 (GAD65), insulin, insulinoma associated protein-2 (IA-2), and zinc transporter 8 (ZnT8) in addition to islet cell antibodies (ICA). A total of 1006 subjects (median age 9 yr) were used as controls. A total of 9.2% (n = 62) of the T1D patients were positive for NPY-LA (p < 0.001) and 7.6% (n = 51) for NPY-PA (p < 0.001) compared to 1.1% (n = 11) in controls. The NPY-LA and NPY-PA appeared together (κ = 0.63; p < 0.001) and the median levels correlated (R² = 0.603; p < 0.001). T1D patients diagnosed after 10 yr of age were at an increased risk for NPYA at diagnosis [odds ratio (OR = 2.46; 95% CI 1.46-4.16; p = 0.001)] adjusted for age at diagnosis, gender, autoantibody positivity, and HLA. NPY is a minor autoantigen in children with newly diagnosed T1D. Therefore, NPY autoantibodies may be investigated in T1D autoimmunity.

Children followed in the TEDDY study are diagnosed with type 1 diabetes at an early stage of disease.

The Environmental Determinants of Diabetes in the Young (TEDDY) study is designed to identify environmental exposures triggering islet autoimmunity and type 1 diabetes (T1D) in genetically high-risk children. We describe the first 100 participants diagnosed with T1D, hypothesizing that (i) they are diagnosed at an early stage of disease, (ii) a high proportion are diagnosed by an oral glucose tolerance test (OGTT), and (iii) risk for early T1D is related to country, population, human leukocyte antigen (HLA)-genotypes and immunological markers. Autoantibodies to glutamic acid decarboxylase (GADA), insulinoma-associated protein 2 (IA-2) and insulin (IAA) were analyzed from 3 months of age in children with genetic risk. Symptoms and laboratory values at diagnosis were obtained and reviewed for ADA criteria. The first 100 children to develop T1D, 33 first-degree relatives (FDRs), with a median age 2.3 yr (0.69-6.27), were diagnosed between September 2005 and November 2011. Although young, 36% had no symptoms and ketoacidosis was rare (8%). An OGTT diagnosed 9/30 (30%) children above 3 yr of age but only 4/70 (5.7%) below the age of 3 yr. FDRs had higher cumulative incidence than children from the general population (p < 0.0001). Appearance of all three autoantibodies at seroconversion was associated with the most rapid development of T1D (HR = 4.52, p = 0.014), followed by the combination of GADA and IAA (HR = 2.82, p < 0.0001). Close follow-up of children with genetic risk enables early detection of T1D. Risk factors for rapid development of diabetes in this young population were FDR status and initial positivity for GADA, IA-2, and IAA or a combination of GADA and IAA.

抗GAD抗体陰性かつ抗IA-2抗体陽性を呈した高齢発症1型糖尿病の1例

An 83-year-old Japanese woman given a diagnosis of type 2 diabetes mellitus 3 years previously was hospitalized for markedly elevated plasma glucose (386 mg/dl) and glycated hemoglobin (9.3%) levels. Laboratory study results showed urinary connecting peptide immunoreactivity (CPR) concentrations of 8.9 μg/day and serum CPR levels <0.2 ng/ml before and 0.3 ng/ml 6 min after glucagon administration, indicating decreased insulin secretion. Although antiglutamic acid dehydrogenase (GAD) antibody levels were negative, insulinoma-associated tryrosine phosphatase-like protein-2 (IA-2) antibody levels were positive (50 U/ml), leading to a diagnosis of type 1 diabetes mellitus. Furthermore, human leukocyte antigen (HLA) typing revealed DRB1*0901, a diabetes-susceptibility gene. Intensive insulin therapy was initiated. This was a rare case of elderly-onset type 1 diabetes.

No Relation Between Cystic Fibrosis–Related Diabetes and Type 1 Diabetes Autoimmunity

Diabetes is the most common comorbidity in individuals with cystic fibrosis. The etiology is poorly understood. Data on the presence of diabetes autoantibodies are conflicting, and little is known about type 1 diabetes gene associations. Our goal was to determine the prevalence of antibodies and HLA haplotypes known to be associated with type 1 diabetes in cystic fibrosis–related diabetes (CFRD). Patients with CFRD with fasting hyperglycemia were recruited from the University of Minnesota. Serum for antibodies and buffy coats for HLA were sent for analysis to the Barbara Davis Center for Childhood Diabetes (BDC). All patients gave informed consent. The Eisenbarth laboratory at BDC serves as the autoantibody/HLA reference laboratory for large national diabetes studies. Insulin, insulinoma-associated protein 2 (IA-2), GAD65, and zinc transporter 8 (ZnT8) autoantibodies were measured by radioimmunoassay …