Childhood screening for type 1 diabetes comparing automated multiplex Antibody Detection by Agglutination-PCR (ADAP) with single plex islet autoantibody radiobinding assays.

BACKGROUND: Two or more autoantibodies against either insulin (IAA), glutamic acid decarboxylase (GADA), islet antigen-2 (IA-2A) or zinc transporter 8 (ZnT8A) denote stage 1 (normoglycemia) or stage 2 (dysglycemia) type 1 diabetes prior to stage 3 type 1 diabetes. Automated multiplex Antibody Detection by Agglutination-PCR (ADAP) assays in two laboratories were compared to single plex radiobinding assays (RBA) to define threshold levels for diagnostic specificity and sensitivity. METHODS: IAA, GADA, IA-2A and ZnT8A were analysed in 1504 (54% females) population based controls (PBC), 456 (55% females) doctor's office controls (DOC) and 535 (41% females) blood donor controls (BDC) as well as in 2300 (48% females) patients newly diagnosed (1-10 years of age) with stage 3 type 1 diabetes. The thresholds for autoantibody positivity were computed in 100 10-fold cross-validations to separate patients from controls either by maximizing the χ2-statistics (chisq) or using the 98th percentile of specificity (Spec98). Mean and 95% CI for threshold, sensitivity and specificity are presented. FINDINGS: The ADAP ROC curves of the four autoantibodies showed comparable AUC in the two ADAP laboratories and were higher than RBA. Detection of two or more autoantibodies using chisq showed 0.97 (0.95, 0.99) sensitivity and 0.94 (0.91, 0.97) specificity in ADAP compared to 0.90 (0.88, 0.95) sensitivity and 0.97 (0.94, 0.98) specificity in RBA. Using Spec98, ADAP showed 0.92 (0.89, 0.95) sensitivity and 0.99 (0.98, 1.00) specificity compared to 0.89 (0.77, 0.86) sensitivity and 1.00 (0.99, 1.00) specificity in the RBA. The diagnostic sensitivity and specificity were higher in PBC compared to DOC and BDC. INTERPRETATION: ADAP was comparable in two laboratories, both comparable to or better than RBA, to define threshold levels for two or more autoantibodies to stage type 1 diabetes. FUNDING: Supported by The Leona M. and Harry B. Helmsley Charitable Trust (grant number 2009-04078), the Swedish Foundation for Strategic Research (Dnr IRC15-0067) and the Swedish Research Council, Strategic Research Area (Dnr 2009-1039). AL was supported by the DiaUnion collaborative study, co-financed by EU Interreg ÖKS, Capital Region of Denmark, Region Skåne and the Novo Nordisk Foundation.

Seroreactivity Against Tyrosine Phosphatase PTPRN Links Type 2 Diabetes and Colorectal Cancer and Identifies a Potential Diagnostic and Therapeutic Target.

Colorectal cancer (CRC) and diabetes are two of the most prevalent chronic diseases worldwide with dysregulated receptor tyrosine kinase signaling and strong co-occurrence correlation. Plasma autoantibodies represent a promising early diagnostic marker for both diseases before symptoms appear. In this study, we explore the value of autoantibodies against receptor-type tyrosine-protein phosphatase-like N (PTPRN; full-length or selected domains) as diagnostic markers using a cohort of individuals with type 2 diabetes (T2D), CRC, or both diseases or healthy individuals. We show that PTPRN autoantibody levels in plasma discriminated between patients with T2D with and without CRC. Consistently, high PTPRN expression correlated with decreased survival of patients with CRC. Mechanistically, PTPRN depletion significantly reduced invasiveness of CRC cells in vitro and liver homing and metastasis in vivo by means of a dysregulation of the epithelial-mesenchymal transition and a decrease of the insulin receptor signaling pathway. Therefore, PTPRN autoantibodies may represent a particularly helpful marker for the stratification of patients with T2D at high risk of developing CRC. Consistent with the critical role played by tyrosine kinases in diabetes and tumor biology, we provide evidence that tyrosine phosphatases such as PTPRN may hold potential as therapeutic targets in patients with CRC.

Genetic variation at ERBB3/IKZF4 and sexual dimorphism in epitope spreading in single autoantibody-positive relatives.

AIMS/HYPOTHESIS: We examined whether the non-HLA susceptibility locus ERBB3/IKZF4 influences progression of type 1 diabetes stage specifically according to sex. METHODS: SNPs of ERBB3 (rs2292239 T/G) and IKZF4 (rs1701704 G/T) were screened by allelic discrimination quantitative PCR assay in first-degree relatives of type 1 diabetes patients who had developed at least one circulating autoantibody. The effect of ERBB3/IKZF4 genotypes and sex, on the progression of single autoantibody positivity to multiple autoantibody positivity and from multiple autoantibody positivity to diabetes, was studied by Kaplan-Meier analysis and multivariate Cox regression. RESULTS: In the cohort of autoantibody-positive first-degree relatives, the risk allele frequencies for ERBB3 rs2292239 (T) and IKZF4 rs1701704 (G) were increased. There was a significant male excess at the stage of multiple autoantibody positivity (p = 0.021). In Kaplan-Meier survival analysis, progression from single to multiple antibody positivity was delayed in female participants with genotype ERBB3 GG (p = 0.018, vs ERBB3 TG+TT) or IKZF4 TT (p = 0.023, vs IKZF4 GT+GG), but not in male participants. In multivariate Cox regression models, the interaction effects between female sex and ERBB3 GG (p = 0.012; HR = 0.305 [95% CI 0.120, 0.773]) or between female sex and IKZF4 TT (p = 0.011; HR = 0.329 [95% CI 0.140, 0.777]) emerged as potential determinants of delayed progression to multiple autoantibodies. The progression from multiple autoantibody positivity to type 1 diabetes appeared not to be influenced by ERBB3/IKZF4. CONCLUSIONS/INTERPRETATION: In siblings and offspring of type 1 diabetes patients, polymorphism in region ERBB3/IKZF4 may affect disease progression at the level of epitope spreading in female individuals. Our findings suggest that interaction between sex and ERBB3/IKZF4 may contribute to the post-pubertal male excess in type 1 diabetes.

Fulminant Type 1 Diabetes Mellitus Accompanied by Positive Conversion of Anti-insulin Antibody after the Administration of Anti-CTLA-4 Antibody Following the Discontinuation of Anti-PD-1 Antibody.

An 80-year-old woman with malignant melanoma received 20 cycles of anti-programmed death 1 (PD-1) antibody (nivolumab) treatment and showed normal glucose tolerance. Three weeks after switching to anti-cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) antibody (ipilimumab), her plasma glucose level was elevated to 639 mg/dL, her HbA1c was 7.7%, and her fastening serum C-peptide immunoreactivity was undetectable. Anti-glutamic acid decarboxylase and insulinoma-associated protein-2 antibodies were negative. She was diagnosed with fulminant type 1 diabetes mellitus (F1DM). Remarkably, her anti-insulin antibody was positively converted, and her Sialylated Carbohydrate Antigen, Krebs von den Lungen-6 levels increased after ipilimumab therapy. She possessed F1DM-susceptible Human Leukocyte Antigen-DR4. A fluorescence activated cell sorting analysis showed an altered T-cell population. This case of F1DM highlights specific mechanisms underlying pancreatic beta cell immunity.

Construction of a novel vaccine by conjugating a B-cell epitope of DPP4 to peptide IA2(5)-P2-1 to significantly control type 1 diabetes in NOD mice.

Type 1 diabetes is a chronic organ-specific autoimmune disease in which selective destruction of insulin-producing ß cells leads to impaired glucose metabolism and its attendant complications. IA2(5)P2-1, a potent immunogenic carrier which designed by our laboratory, can induce high titer specific antibodies when carry a B cell epitope, such as B cell epitopes of DPP4, xanthine oxidase, and Urate transporter protein. In this report, we describe a novel multi-epitope vaccine composing a peptide of DPP4, an anti-diabetic B epitope of Insulinoma antigen-2(IA-2) and a Th2 epitope (P2:IPALDSLTPANED) of P277 peptide in human heat shock protein 60 (HSP60). Immunization with the multi-epitope vaccine in non-obese diabetic (NOD) mice successfully induced specific anti-DPP4 antibody, inhibited plasma DPP4 activity, and increased serum GLP-1 level. Moreover, this antibody titer was correlated with the dose of immunization (20µg, 100µg). Inoculation of this vaccine in NOD mice significantly control blood glucose level, improved glucose excursion and increased insulin level in vivo. Consistent with a lower diabetic and insulitis incidence, a induced splenic T cells proliferation and tolerance were observed. IFN-γ secretion reduced and IL-10 increased significantly in the D41-IA2(5)-P2-1 treated mice compared to P277 and control group due to the potential immunomodulatory effect of the epitope in the vaccine. Immunohistochemical analysis and cytometry showed a rebalance of Th1/Th2 in NOD mice. Our results demonstrate that this multi-epitope vaccine may serve as a promising therapeutic approach for type 1 diabetes.

Tracking the Antibody Immunome in Type 1 Diabetes Using Protein Arrays.

We performed an unbiased proteome-scale profiling of humoral autoimmunity in recent-onset type 1 diabetes (T1D) patients and nondiabetic controls against ∼10 000 human proteins using a Nucleic Acid Programmable Protein Array (NAPPA) platform, complemented by a knowledge-based selection of proteins from genes enriched in human pancreas. Although the global response was similar between cases and controls, we identified and then validated six specific novel T1D-associated autoantibodies (AAbs) with sensitivities that ranged from 16 to 27% at 95% specificity. These included AAbs against PTPRN2, MLH1, MTIF3, PPIL2, NUP50 (from NAPPA screening), and QRFPR (by targeted ELISA). Immunohistochemistry demonstrated that NUP50 protein behaved differently in islet cells, where it stained both nucleus and cytoplasm, compared with only nuclear staining in exocrine pancreas. Conversely, PPIL2 staining was absent in islet cells, despite its presence in exocrine cells. The combination of anti-PTPRN2, -MLH1, -PPIL2, and -QRFPR had an AUC of 0.74 and 37.5% sensitivity at 95% specificity. These data indicate that these markers behave independently and support the use of unbiased screening to find biomarkers because the majority was not predicted based on predicted abundance. Our study enriches the knowledge of the "autoantibody-ome" in unprecedented breadth and width.

Capillary blood islet autoantibody screening for identifying pre-type 1 diabetes in the general population: design and initial results of the Fr1da study.

INTRODUCTION: Type 1 diabetes can be diagnosed at an early presymptomatic stage by the detection of islet autoantibodies. The Fr1da study aims to assess whether early staging of type 1 diabetes (1) is feasible at a population-based level, (2) prevents severe metabolic decompensation observed at the clinical manifestation of type 1 diabetes and (3) reduces psychological distress through preventive teaching and care. METHODS AND ANALYSIS: Children aged 2-5 years in Bavaria, Germany, will be tested for the presence of multiple islet autoantibodies. Between February 2015 and December 2016, 100 000 children will be screened by primary care paediatricians. Islet autoantibodies are measured in capillary blood samples using a multiplex three-screen ELISA. Samples with ELISA results >97.5th centile are retested using reference radiobinding assays. A venous blood sample is also obtained to confirm the autoantibody status of children with at least two autoantibodies. Children with confirmed multiple islet autoantibodies are diagnosed with pre-type 1 diabetes. These children and their parents are invited to participate in an education and counselling programme at a local diabetes centre. Depression and anxiety, and burden of early diagnosis are also assessed. RESULTS: Of the 1027 Bavarian paediatricians, 39.3% are participating in the study. Overall, 26 760 children have been screened between February 2015 and November 2015. Capillary blood collection was sufficient in volume for islet autoantibody detection in 99.46% of the children. The remaining 0.54% had insufficient blood volume collected. Of the 26 760 capillary samples tested, 0.39% were positive for at least two islet autoantibodies. DISCUSSION: Staging for early type 1 diabetes within a public health setting appears to be feasible. The study may set new standards for the early diagnosis of type 1 diabetes and education. ETHICS DISSEMINATION: The study was approved by the ethics committee of Technische Universität München (Nr. 70/14).

Discovery of a Selective Islet Peptidome Presented by the Highest-Risk HLA-DQ8trans Molecule.

HLA-DQ2/8 heterozygous individuals are at far greater risk for type 1 diabetes (T1D) development by expressing HLA-DQ8trans on antigen-presenting cells compared with HLA-DQ2 or -DQ8 homozygous individuals. Dendritic cells (DC) initiate and shape adaptive immune responses by presenting HLA-epitope complexes to naïve T cells. To dissect the role of HLA-DQ8trans in presenting natural islet epitopes, we analyzed the islet peptidome of HLA-DQ2, -DQ8, and -DQ2/8 by pulsing DC with preproinsulin (PPI), IA-2, and GAD65. Quality and quantity of islet epitopes presented by HLA-DQ2/8 differed from -DQ2 or -DQ8. We identified two PPI epitopes solely processed and presented by HLA-DQ2/8 DC: an HLA-DQ8trans-binding signal-sequence epitope previously identified as CD8 T-cell epitope and a second epitope that we previously identified as CD4 T-cell epitope with increased binding to HLA-DQ8trans upon posttranslational modification. IA-2 epitopes retrieved from HLA-DQ2/8 and -DQ8 DC bound to HLA-DQ8cis/trans. No GAD65 epitopes were eluted from HLA-DQ. T-cell responses were detected against the novel islet epitopes in blood from patients with T1D but scantly detected in healthy donor subjects. We report the first PPI and IA-2 natural epitopes presented by highest-risk HLA-DQ8trans. The selective processing and presentation of HLA-DQ8trans-binding islet epitopes provides insight in the mechanism of excessive genetic risk imposed by HLA-DQ2/8 heterozygosity and may assist immune monitoring of disease progression and therapeutic intervention as well as provide therapeutic targets for immunotherapy in subjects at risk for T1D.

A multiplex assay combining insulin, GAD, IA-2 and transglutaminase autoantibodies to facilitate screening for pre-type 1 diabetes and celiac disease.

At the current time, multiple candidate interventions are being proposed to abrogate or slow progression to type 1 diabetes (T1D) among islet autoantibody (iAb) positive subjects, but mass screening for eligible subjects and the general population remains a laborious and inefficient process. We have recently developed and extensively validated nonradioactive iAb assays using electrochemiluminescense (ECL) detection with an excellent sensitivity and specificity compared to the gold-standard radioassays. Using ECL detection on a platform from MesoScale Discovery (MSD) allows the measurement of four antibodies in a single well using a small blood volume (6 µl). In the present study using a MSD QuickPlex 4-Spot plate, we successfully combined three iAb to insulin (IAA), GAD65 (GADA), and IA-2 (IA-2A) with tissue transglutaminase autoantibodies (TGA) in a single well of a 96 well plate. We tested 40 new onset T1D patients, all positive for at least one iAb and a half of them positive for TGA by radioassay, as well as 50 healthy controls. The multiplex assay retained 100% sensitivity and 100% specificity for all four autoantibodies in terms of positivity identified in patients versus normal controls compared to the corresponding standard radioassays and our single ECL assays. The multiplex ECL assay was able to identify more positivity than current radioassays for IAA and TGA. The development of this multiplex assay will facilitate high-throughput screening for T1D and celiac disease risk in the general population.

HLA-DR4-associated T and B cell responses to specific determinants on the IA-2 autoantigen in type 1 diabetes.

Autoantibodies to IA-2 in type 1 diabetes are associated with HLA-DR4, suggesting influences of HLA-DR4-restricted T cells on IA-2-specific B cell responses. The aim of this study was to investigate possible T-B cell collaboration by determining whether autoantibodies to IA-2 epitopes are associated with T cell responses to IA-2 peptides presented by DR4. T cells secreting the cytokines IFN-γ and IL-10 in response to seven peptides known to elicit T cell responses in type 1 diabetes were quantified by cytokine ELISPOT in HLA-typed patients characterized for Abs to IA-2 epitopes. T cell responses were detected to all peptides tested, but only IL-10 responses to 841-860 and 853-872 peptides were associated with DR4. Phenotyping by RT-PCR of FACS-sorted CD45RO(hi) T cells secreting IL-10 in response to these two peptides indicated that these expressed GATA-3 or T-bet, but not FOXP3, consistent with these being Th2 or Th1 memory T cells rather than of regulatory phenotype. T cell responses to the same two peptides were also associated with specific Abs: those to 841-860 peptide with Abs to juxtamembrane epitopes, which appear early in prediabetes, and those to peptide 853-872 with Abs to an epitope located in the 831-862 central region of the IA-2 tyrosine phosphatase domain. Abs to juxtamembrane and central region constructs were both DR4 associated. This study identifies a region of focus for B and T cell responses to IA-2 in HLA-DR4 diabetic patients that may explain HLA associations of IA-2 autoantibodies, and this region may provide a target for future immune intervention to prevent disease.

Type 2 diabetes mellitus in children and adolescents.

On the basis of strong research evidence and consensus, type 1 diabetes mellitus (DM) remains the most common form of DM in children and adolescents. The incidence of type 2 DM in the pediatric population is rapidly increasing because of the obesity epidemic, and minority groups are disproportionately affected. (2) (10) (19) On the basis of some research evidence and consensus, it can be challenging to initially differentiate between type 2 DM and type 1 DM clinically because of the increased prevalence of obesity, the complex interplay of autoimmunity and obesity, and common symptoms at presentation. (1) (10) (19) Significant evidence and consensus support a genetic basis for the development of type 2 DM in children. Physicians should routinely screen at risk children older than age 10 years for DM. Screening criteria include obesity, a family history of type 2 DM, a minority racial or ethnic background, acanthosis nigricans, or other diseases associated with insulin resistance, including polycystic ovary syndrome, hypertension, or dyslipidemia. (1) (10) (18) (19) On the basis of consensus, diagnosis of type 2 DM can be confirmed by an elevated fasting blood glucose level greater than 126 mg/dl (7.0 mmol/L), an elevated 2-hour plasma glucose greater than 200 mg/dL (11.1 mmol/L) on an oral glucose tolerance test, an elevated random blood glucose greater than 200 mg/dL (11.1 mmol/L), or a hemoglobin A1c level greater than 6.5% with suggestive symptoms. (10) According to strong research evidence and consensus, once the diagnosis has been made, treatment should be based on the acuity of presentation and should focus on lifestyle modification and on normalizing hyperglycemia to minimize complications. Metformin is currently first-line treatment for type 2 DM in children and adolescents older than age 10 years who present nonacutely. (18) (19) Strong research evidence and consensus demonstrate that because type 2 DM has an insidious onset, microvascular and macrovascular complications can be present at the time of diagnosis. Patients should be screened for the presence of complications when the diagnosis of type 2 DM is made and in follow-up. (6) (10).

Types of pediatric diabetes mellitus defined by anti-islet autoimmunity and random C-peptide at diagnosis.

OBJECTIVE: To test the hypothesis that anti-islet autoantibody expression and random serum C-peptide obtained at diagnosis define phenotypes of pediatric diabetes with distinct clinical features. SUBJECTS: We analyzed 607 children aged <19 yr consecutively diagnosed with diabetes after exclusion of 13% of cases with secondary diabetes (e.g., cystic fibrosis related, steroid induced) and 7.3% of cases lacking measurement of C-peptide and/or autoantibodies. METHODS: Autoantibody positivity (A+) was defined as ≥ 1 positive out of GAD65, insulin, and ICA512 antibodies. Preserved beta-cell function (ß+) was defined as random serum C-peptide at diagnosis ≥ 0.6 ng/mL. Body mass index (BMI) was measured at median 1.2 months after diagnosis. Characteristics at diagnosis and 2 yr (range 18-30 months) after diagnosis were compared among groups. RESULTS: Autoantibody expression and C-peptide at diagnosis defined the following groups: A+ß- (52.1% of the children), A+ß+ (32.8%), A-ß+ (12.5%), and A-ß- (2.6%). These four groups differed in gender, race/ethnicity, and clinical characteristics at diagnosis [i.e., age, pubertal development, obesity/overweight, diabetic ketoacidosis, glycemia, and hemoglobin A1c (HbA1c)] and at 2 yr (i.e., clinical diagnosis, treatment, and HbA1c) (all p < 0.0001). Among all ß+ children, C-peptide >2 ng/mL was associated with lower HbA1c at onset (p = 0.0001) and, in the A+ß+ subgroup, with higher frequency of achieving HbA1c < 7% at 2 yr (p = 0.03). All three patients (0.7% of total) with monogenic diabetes (maturity onset diabetes of the young, MODY) were A-ß+ with C-peptide between 0.6 and 2 ng/mL. CONCLUSIONS: Anti-islet autoantibodies status and serum random C-peptide at diagnosis define four distinct phenotypes of pediatric diabetes with prognostic value.

Characteristics of rapid vs slow progression to type 1 diabetes in multiple islet autoantibody-positive children.

AIMS/HYPOTHESIS: Islet autoantibody-positive children progress to type 1 diabetes at variable rates. In our study, we asked whether characteristic autoantibody and/or gene profiles could be defined for phenotypes showing extreme progression. METHODS: Autoantibodies to insulin (IAA), GAD (GADA), insulinoma-associated antigen-2 (IA-2A) and zinc transporter 8 (ZnT8A) were measured in follow-up sera, and genotyping for type 1 diabetes susceptibility genes (HLA-DR/HLA-DQ, INS variable number of tandem repeats [VNTR] and single nucleotide polymorphisms at PTPN22, PTPN2, ERBB3, IL2, SH2B3, CTLA4, IFIH1, KIAA0350 [also known as CLEC16A], CD25, IL18RAP, IL10, COBL) was performed on the DNA samples of children born to a parent with type 1 diabetes and prospectively followed from birth for up to 22 years. RESULTS: Of the 1,650 children followed, 23 developed multiple autoantibodies and progressed to diabetes within 3 years (rapid progressors), while 24 children developed multiple autoantibodies and remained non-diabetic for more than 10 years from seroconversion (slow progressors). Rapid and slow progressors were similar with respect to HLA-DR/HLA-DQ genotypes, development of IAA, GADA and ZnT8A, and progression to multiple autoantibodies. In contrast, IA-2A development was considerably delayed in the slow progressors. Furthermore, both groups were effectively distinguished by the combined presence or absence of type 1 diabetes susceptibility alleles of non-HLA genes, most notably IL2, CD25, INS VNTR, IL18RAP, IL10, IFIH1 and PTPN22, and discrimination was improved among children carrying high-risk HLA-DR/HLA-DQ genotypes. CONCLUSIONS/INTERPRETATION: Our data suggest that genotypes of non-HLA type 1 diabetes susceptibility genes influence the likelihood or rate of diabetes progression among children with multiple islet autoantibodies.

The core cysteines, (C909) of islet antigen-2 and (C945) of islet antigen-2ß, are crucial to autoantibody binding in type 1 diabetes.

Cysteines are thought integral to conformational epitopes of islet antigen-2 (IA-2) autoantibodies (IA-2A), possibly through disulfide bond formation. We therefore investigated which cysteines are critical to IA-2A binding in patients with newly diagnosed type 1 diabetes. All 10 cysteines in the intracellular domain of IA-2 were modified to serine by site-directed mutagenesis, and the effects of these changes on autoantibody binding in comparison with wild-type control were investigated by radiobinding assay. Mutation of the protein tyrosine phosphatase (PTP) core cysteine (C909) in IA-2 caused large reductions in autoantibody binding. In contrast, little or no reduction in binding was seen following substitution of the other cysteines. Modification of the core cysteine (C945) in IA-2ß also greatly reduced autoantibody binding. Lysine substitution of glutamate-836 in IA-2 or glutamate-872 in IA-2ß resulted in modest reductions in binding and identified a second epitope region. Binding to IA-2 PTP and IA-2ß PTP was almost abolished by mutation of both the core cysteine and these glutamates. The core cysteine is key to the major PTP conformational epitope, but disulfide bonding contributes little to IA-2A epitope integrity. In most patients, at disease onset, >90% of antibodies binding to the PTP domain of IA-2 recognize just two epitope regions.

GADA positivity at onset of type 1 diabetes is a risk factor for the development of autoimmune thyroiditis.

AIM: To evaluate whether the presence of diabetes-specific autoantibodies may predict the development of autoimmune thyroiditis (AIT) in children with type 1 diabetes (T1D). METHODS: Glutamic acid decarboxylase antibodies (GADA), tyrosine phosphatase IA2 antibodies (IA2A), and insulin autoantibodies (IAA) were determined at T1D onset in 341 children and adolescents. Thyroid antibodies (anti-TG, anti-TPO), thyroid stimulating hormone (TSH), T(3) and T(4) were measured in 335 patients at T1D onset and thereafter annually with a follow-up time of 1-15 yr. In case of thyroid antibody positivity and/or TSH elevation, thyroid gland sonography was performed. Treatment with l-thyroxine was started if persistent elevation of TSH and/or thyroid volume was present. RESULTS: The majority of patients (92.1%) had at least one T1D antibody (71.6% GADA, 73.0% IA2A, and 44.9% IAA). GADA positive patients were older than those without GADA (p < 0.001). Thyroid autoimmunity was found in 15 of 335 patients (4.5%) at T1D onset with female preponderance (p = 0.013). At the end of follow-up, 70 patients (20.9%) had developed thyroid autoantibodies [cumulative incidence (CI) 0.36 ± 0.06 at 10 yr of T1D]. In 30 patients (9.0%), AIT was diagnosed up to 9.4 yr after T1D onset (CI 0.24 ± 0.06 at 10 yr). AIT incidence was not influenced by IAA or IA2A positivity. In multivariate analysis, GADA positive patients were estimated to have a 3.5-fold increased risk of AIT (CI 0.31 ± 0.11 at 10 yr) compared to those without GADA (p = 0.024). CONCLUSION: Based on the present results, a special focus should be given to GADA positive patients concerning screening for AIT as they are at increased risk to develop autoimmune thyroiditis.

Elevated expression of MCP-1, IL-2 and PTPR-N in basal ganglia of Tourette syndrome cases.

BACKGROUND: Post-infectious autoimmunity has been implicated in pathogenesis of Tourette's syndrome (TS) but no evidence of inflammation in central nervous system has been reported yet. We evaluated the expression of genes encoding selected inflammatory factors in post-mortem specimen of adult TS patients: interferon-γ (a cytokine released from CD8 and Thelper 1 CD4 subset of T lymphocytes), interleukin-2 (IL-2, a growth factor derived from T lymphocytes), interleukin-1 ß (a cytokine involved in initiation of inflammation), monocyte chemotactic factor -1 (MCP-1, a marker of chronic inflammation) and CD45 (pan-leukocytic marker). For validation purposes, we determined expression of three genes that were previously reported to be elevated in post-mortem specimen of other TS cases: protein tyrosine phosphatase receptor-N (PTPR-N), PTPR-U and recoverin. METHODS: Total RNA was isolated from formalin fixed brain tissue sections of basal ganglia area from four patients with TS and four control subjects, and real-time reverse transcription-polymerase chain reaction analysis was employed to quantitatively evaluate gene expression of the selected genes. RESULTS: Significantly increased expression of MCP-1, IL-2 and PTPR-N was observed in TS cases (6.5-fold, 2.3-fold and 16.1-fold increase, respectively, p<0.05). CONCLUSIONS: Elevated expression of MCP-1 and IL-2 supports the possibility of chronic inflammatory processes in the basal ganglia. Replication of elevated expression of PTPR-N in TS specimen suggests that pathway(s) involving this molecule may be important in TS pathogenesis.

Effects of therapy in type 1 and type 2 diabetes mellitus with a peptide derived from islet neogenesis associated protein (INGAP).

BACKGROUND: Islet neogenesis associated protein (INGAP) has beta cell regenerating effects in experimental models. METHODS: Subjects with T1DM (N = 63) and T2DM (N = 126) received 300 or 600 mg/day of INGAP peptide in a 90 day, randomized, double-blind, placebo-controlled trial. RESULTS: In T1DM, on-treatment Arginine-stimulated C-peptide (AUC(0-30)) significantly increased from baseline in the 600 mg group (p = 0.0058 versus placebo); no significant changes were seen in the 300 mg group. In T2DM, stimulated C-peptide was significantly better preserved in the 600 mg group compared to placebo at day 120, 30 days after washout (p = 0.031 versus placebo), but did not reach statistical significance during treatment or in the 300 mg group. In T2DM, A1C decreased significantly more in the 600 mg group compared to placebo at day 90 (-0.94% versus -0.47%, respectively, p = 0.009) and day 120, 30 days after washout (-0.73% versus -0.24%, respectively, p = 0.013). This was accompanied by significant reductions in mean glucose. No difference from placebo was detected in the 300 mg group or in T1DM. Injection site reactions were the most common adverse event, occurring in 8 (36%) of placebo, 19 (90%) of 300 mg, and 15 (75%) of 600 mg groups (T1DM) and 14 (33%) of placebo, 27 (64%) of 300 mg, and 29 (69%) of 600 mg groups (T2DM). CONCLUSIONS: INGAP peptide increases C-peptide secretion in T1DM and improves glycaemic control in T2DM. Longer-term exposure, more frequent dosing, better tolerated formulations or combination with other therapies may be necessary to achieve optimal clinical response.

Prediction of HLA-DQ8beta cell peptidome using a computational program and its relationship to autoreactive T cells.

The goal was to identify HLA-DQ8-bound beta cell epitopes important in the T cell response in autoimmune diabetes. We first identified HLA-DQ8 (DQA1*0301/DQB1*0302) beta cell epitopes using a computational approach and then related their identification to CD4 T cell responses. The computational program (TEA-DQ8) was adapted from one previously developed for identifying peptides bound to the I-A(g7) molecule and based on a library of naturally processed peptides bound to HLA-DQ8 molecules of antigen-presenting cells. We then examined experimentally the response of NOD.DQ8 mice immunized with peptides derived from the Zinc transporter 8 protein. Log-of-odds scores on peptides were experimentally validated as an indicator of peptide binding to HLA-DQ8 molecules. We also examined previously published data on diabetic autoantigens, including glutamic acid decarboxylase-65, insulin and insulinoma-associated antigen-2, all tested in NOD.DQ8 transgenic mice. In all examples, many peptides identified with a favorable binding motif generated an autoimmune T cell response, but importantly many did not. Moreover, some peptides with weak-binding motifs were immunogenic. These results indicate the benefits and limitations in predicting autoimmune T cell responses strictly from MHC-binding data. TEA-DQ8 performed significantly better than other prediction programs.

Gene silencing of phogrin unveils its essential role in glucose-responsive pancreatic beta-cell growth.

OBJECTIVE: Phogrin and IA-2, autoantigens in insulin-dependent diabetes, have been shown to be involved in insulin secretion in pancreatic beta-cells; however, implications at a molecular level are confusing from experiment to experiment. We analyzed biological functions of phogrin in beta-cells by an RNA interference technique. RESEARCH DESIGN AND METHODS: Adenovirus-mediated expression of short hairpin RNA specific for phogrin (shPhogrin) was conducted using cultured beta-cell lines and mouse islets. Both glucose-stimulated insulin secretion and cell proliferation rate were determined in the phogrin-knockdown cells. Furthermore, protein expression was profiled in these cells. To see the binding partner of phogrin in beta-cells, coimmunoprecipitation analysis was carried out. RESULTS: Adenoviral expression of shPhogrin efficiently decreased its endogenous expression in pancreatic beta-cells. Silencing of phogrin in beta-cells abrogated the glucose-mediated mitogenic effect, which was accompanied by a reduction in the level of insulin receptor substrate 2 (IRS2) protein, without any changes in insulin secretion. Phogrin formed a complex with insulin receptor at the plasma membrane, and their interaction was promoted by high-glucose stimulation that in turn led to stabilization of IRS2 protein. Corroboratively, phogrin knockdown had no additional effect on the proliferation of beta-cell line derived from the insulin receptor-knockout mouse. CONCLUSIONS: Phogrin is involved in beta-cell growth via regulating stability of IRS2 protein by the molecular interaction with insulin receptor. We propose that phogrin and IA-2 function as an essential regulator of autocrine insulin action in pancreatic beta-cells.

Radiobinding assay for detecting autoantibodies to single epitopes.

Autoantibodies, a hallmark of autoimmune disease, are directed against diverse antigens and epitopes. This diversity aids in characterising disease progression and identifying disease-associated autoantibodies. Here we aimed to develop a sensitive assay to detect and quantify epitope-specific autoantibodies. We generated constructs to integrate known peptide epitopes into the TrxA protein, and used these to in vitro synthesize radio-labelled proteins for a radiobinding assay (RBA). This assay was first validated with an animal model using mice immunized with the MOG(40-55) peptide. Using type 1 diabetes-associated protein tyrosine phosphatase-like autoantigen IA-2 as a human model, we expressed IA-2(609-621), IA-2(619-631), or IA-2(609-631) peptide in the TrxA construct and used the RBA to test sera from 113 patients with type 1 diabetes and 87 controls. Antibodies were detected to the IA-2(609-631) epitope in 37 of 113 patient sera and one control; 17 sera were reactive to the IA-2(609-621) (JM1) epitope, and 16 to the IA-2(619-631) (JM2) epitope. Interestingly, a novel third epitope (JM3) was identified in 7 sera that reacted to IA-2(609-631) but not the JM1 and JM2 sub-specificities. An ELISA using IA-2(609-631) was less sensitive than the RBA, as it detected only some of the JM1 and JM3 antibody positive sera and none of the JM2. Mutagenesis of single IA-2(609-631) amino acids in combination with the RBA showed that antibodies to JM2 and JM3 were highly diverse in their specific residue requirements. Our strategy using in vitro synthesized antigens and the RBA was thus a highly sensitive and versatile method to identify epitopes and quantify epitope-specific antibodies.