Association of subclass distribution of insulin antibody with glucose control in insulin-treated type 2 diabetes mellitus: a retrospective observational study.

Objective: To examine the distribution and effects of the subclass of insulin antibodies on glucose control and side events in patients with type 2 diabetes treated with premixed insulin analog. Methods: A total of 516 patients treated with premixed insulin analog were sequentially enrolled from the First Affiliated Hospital of Nanjing Medical University from June 2016 to August 2020. Subclass-specific insulin antibodies (IAs) (IgG1-4, IgA, IgD, IgE, and IgM) were detected in IA-positive patients by electrochemiluminescence. We analyzed glucose control, serum insulin, and insulin-related events between IA-positive and IA-negative groups, as well as among patients with different IA subclasses. Results: Overall, 98 of 516 subjects (19.0%) were positive for total IAs after premixed insulin analog therapy; of these participants, 92 had subclass IAs, and IgG-IA was the predominant subclass, followed by IgE-IA. IAs were associated with serum total insulin increase and local injection-site reactions but not glycemic control and hypoglycemia. In the subgroup analysis in patients with IA-positive, the IgE-IA and IA subclass numbers were more associated with increased serum total insulin levels. Additionally, IgE-IA might be correlated more strongly with local responses and weakly with hypoglycemia, while IgM-IA might be correlated more strongly with hypoglycemia. Conclusion: We concluded that IAs or IA subclasses might be associated with unfavorable events in patients receiving premixed insulin analog therapy, which can be used as an adjunctive monitoring indicator in clinical insulin trials.

Dynamics of Islet Autoantibodies During Prospective Follow-Up From Birth to Age 15 Years.

CONTEXT: We set out to characterize the dynamics of islet autoantibodies over the first 15 years of life in children carrying genetic susceptibility to type 1 diabetes (T1D). We also assessed systematically the role of zinc transporter 8 autoantibodies (ZnT8A) in this context. DESIGN: HLA-predisposed children (N = 1006, 53.0% boys) recruited from the general population during 1994 to 1997 were observed from birth over a median time of 14.9 years (range, 1.9-15.5 years) for ZnT8A, islet cell (ICA), insulin (IAA), glutamate decarboxylase (GADA), and islet antigen-2 (IA-2A) antibodies, and for T1D. RESULTS: By age 15.5 years, 35 (3.5%) children had progressed to T1D. Islet autoimmunity developed in 275 (27.3%) children at a median age of 7.4 years (range, 0.3-15.1 years). The ICA seroconversion rate increased toward puberty, but the biochemically defined autoantibodies peaked at a young age. Before age 2 years, ZnT8A and IAA appeared commonly as the first autoantibody, but in the preschool years IA-2A- and especially GADA-initiated autoimmunity increased. Thereafter, GADA-positive seroconversions continued to appear steadily until ages 10 to 15 years. Inverse IAA seroconversions occurred frequently (49.3% turned negative) and marked a prolonged delay from seroconversion to diagnosis compared to persistent IAA (8.2 vs 3.4 years; P = .01). CONCLUSIONS: In HLA-predisposed children, the primary autoantibody is characteristic of age and might reflect the events driving the disease process toward clinical T1D. Autoantibody persistence affects the risk of T1D. These findings provide a framework for identifying disease subpopulations and for personalizing the efforts to predict and prevent T1D.

The association between anti-insulin aspart antibodies and the pharmacokinetic and pharmacodynamic characteristics of fast-acting insulin aspart in children and adolescents with type 1 diabetes.

BACKGROUND: Fast-acting insulin aspart (faster aspart) is a novel formulation of insulin aspart (IAsp) ensuring ultrafast absorption and effect. AIM: To compare the pharmacokinetics between faster aspart and IAsp, based on free or total IAsp measurement, and investigate the association between anti-IAsp antibodies and faster aspart and IAsp pharmacological properties in children and adolescents with type 1 diabetes (T1D). METHODS: In a randomized, two-period crossover trial, 12 children, 16 adolescents, and 15 adults (6-11, 12-17, and 18-64 years) received 0.2 U/kg double-blindsingle-dose subcutaneous faster aspart or IAsp followed by a standardized liquid meal test. RESULTS: Across age groups, the pharmacokinetic profile was left-shifted including greater early exposure for faster aspart vs IAsp irrespective of free or total IAsp assay. Onset of appearance occurred 2.4 to 5.0 minutes (free) or 1.8 to 3.0 minutes (total) earlier for faster aspart vs IAsp (P < .05). Treatment ratios (faster aspart/IAsp) for 0 to 30 minutes IAsp exposure were 1.60 to 2.11 and 1.62 to 1.96, respectively (children, free: P = .062; otherwise P < .05). The ratio of free/total IAsp for overall exposure (AUCIAsp,0-t ) was negatively associated with anti-IAsp antibody level across age. Pooling with a previous similar trial showed no clear association between anti-IAsp antibodies and meal test 1- or 2-hour postprandial glucose increment independent of age and insulin treatment (R2 ≤ .070; P ≥ .17). CONCLUSIONS: In children and adolescents with T1D, faster aspart provides ultrafast pharmacokinetics irrespective of free or total IAsp assay. Elevated anti-IAsp antibodies are associated with higher total IAsp concentration, but do not impact faster aspart and IAsp glucose-lowering effect.

Regional variation of human pancreatic islets dimension and its impact on beta cells in Indian population.

Background & objectives: Islet of Langerhans, the endocrine pancreas plays a significant role in glucose metabolism. Obesity and insulin resistance are the major factors responsible for beta cell dysfunction. Asian Indian population has increased susceptibility to diabetes in spite of having lower BMI. The morphology of islets plays a significant role in beta cell function. The present study was designed for better understanding the morphology, composition and distribution of islets in different parts of the pancreas and its impact on beta cell proportion. Methods: We observed islet morphology and beta cell area proportion by Large-scale computer-assisted analysis in 20 adult human pancreases in non-diabetic Indian population. Immunohistochemical staining with anti-synaptophysin and anti-insulin antibody was used to detect islet and beta cells respectively. Whole slide images were analyzed using ImageJ software. Results: Endocrine proportion were heterogeneously increasing from head to tail with maximum islet and beta cell distribution in the tail region. Larger islets were predominately confined to the tail region. The islets in Indian population were relatively smaller in size, but they have more beta cells (20%) when compared to American population. Interpretation & conclusions: The beta cells of larger islets are functionally more active than the smaller islets via paracrine effect. Thus, reduction in the number of larger islets may be one of the probable reasons for increased susceptibility of Indians to diabetes even at lower BMI. Knowledge about the regional distribution of islets will help the surgeons to preserve the islet rich regions during surgery.

Insulin Autoimmune Syndrome: a rare case of hypoglycaemia resolving with immunosuppression.

We report a case of a 58-year-old male presenting with confusion and hypoglycaemia. There had been no prior exposure to oral hypoglycaemic agents or insulin. He was found to have inappropriate endogenous hyperinsulinaemia. Insulinoma was excluded by detailed endocrine assessment. Insulin antibodies were positive in keeping with a diagnosis of insulin autoimmune syndrome (IAS). He was treated with prednisolone 5mg once daily and nutritional supplements leading to resolution of acute confusion and hypoglycaemic episodes. The patient also had severe psoriasis and following discharge was treated with a variety of immunosuppressant therapies. This was associated with disappearance of insulin antibodies after twelve months of follow up. While it is possible that there was spontaneous resolution of insulin antibodies, we speculate that his prednisolone and immunosuppressant therapy may have suppressed insulin antibody production. There are several well recognised associations with IAS and autoimmune conditions, including Grave's disease, systemic lupus erythematous and rheumatoid arthritis. To our knowledge this is the first reported case of insulin autoimmune syndrome, resolving with immunosuppressant treatment of psoriasis.

Could ZnT8 antibodies replace ICA, GAD, IA2 and insulin antibodies in the diagnosis of type 1 diabetes?

BACKGROUND: The zinc transporter 8 (ZnT8) is an islet ß-cell secretory granule membrane protein coded by the SLC30A8 gene, identified as a novel autoantigen in human type 1 diabetes (T1D). As no data of ZnT8ab in Algerian patients have been reported, we aim to evaluate the prevalence of ZnT8ab in young Algerians with T1D and determine whether ZnT8ab could be a better diagnostic tool to replace the other conventional autoantibodies detected in patients with type 1 diabetes. For this purpose, we evaluated the prevalence of islets cells antibodies (ICA), glutamic acid decarboxylase (GAD), islet antigen type 2 (IA2), insulin (IA) autoantibodies (ab) and for the first time in Algeria, the zinc transporter 8 (ZnT8) in young Algerian patients with type 1 diabetes. PATIENTS AND METHODS: In our cross-sectional study, 160 patients between 1 and 35 years old, diagnosed with type 1 diabetes were enrolled. ICAab was analyzed by indirect immunofluorescence (IIF), GADab, IA2ab, IAab and ZnT8ab were analyzed by ELISA, fasting blood glucose was performed by enzymatic method (glucose-oxidase) and HbA1c by turbid metric method. RESULTS: Our cohort was composed with 74 males and 86 females (OR=1.16); the mean of age was 14.09 [1-35] years old and the median diabetes duration was 4.10 [1-18] years. Our cohort had a mean of HbA1c of 9.22 [5.40-15]%, the mean of birth weight was 3360.52 [2200-4800]g; the mean of BMI was 19.30 [16.04-22.46]kg/m2. Out of 160 patients, 44 (27.5%) were under mother breastfeeding and 116/160 (72.5%) were under artificial feeding. One antibody, at least, was found in 94.38% and the ZnT8ab was significantly more positive in females (70.3%) than in males (10.7%) (***P=8.033×10-15). The concentration of ZnT8ab was higher in females than in males (females=122.25UI/mL versus males=51.38UI/mL; *P=0.03); ICAab, GADab and ZnT8ab were more present in patients with consanguineous parents (***P=0.0002, *P=0.019 and *P=0.03; respectively) CONCLUSION: Our study on ZnT8ab in T1D is the first in the Maghreb region and we observed a prevalence of 46.25%. The positivity of ZnT8ab enabled us to classify in T1DA 50% of diabetics with obvious T1D phenotype and negative routine autoantibodies, thus ZnT8ab is a good tool for differential diagnosis of type 1 diabetes. According to our results, a simultaneous analysis for ZnT8 and IA2 autoantibodies can be a better and efficient diagnosis of type 1A diabetes from the beginning of the disease.

A novel LIPS assay for insulin autoantibodies.

AIMS: Insulin autoantibodies (IAA) are often the first marker of autoimmunity detected in children in the preclinical phase of type 1 diabetes (T1D). Currently, the vast majority of laboratories adopt the radiobinding micro-assay (RBA) for measuring IAA. Our aim was to replace RBA with a novel non-radioactive IAA Luciferase Immuno Precipitation System (LIPS) assay with improved performance. METHODS: We developed (pro)insulin antigens with alternative placements of a NanoLuc™ luciferase reporter (NLuc). Performance in LIPS was evaluated by testing sera from new onset T1D (n = 80), blood donors (n = 123), schoolchildren (n = 186), first-degree relatives (FDRs) from the Bart's Oxford family study (n = 53) and from the Belgian Diabetes Registry (n = 136), coded sera from the Islet Autoantibody Standardization Program (IASP) (T1D n = 50, blood donors n = 90). RESULTS: IAA LIPS based on B chain-NLuc proinsulin or B chain-NLuc insulin, in which NLuc was fused at the C-terminus of the insulin B chain, required only 2 µL of serum and a short incubation time, showed high concordance with RBA (Spearman r = 0.866 and 0.833, respectively), high assay performance (B chain-NLuc proinsulin ROC-AUC = 0.894 and B chain-NLuc insulin ROC-AUC = 0.916), and an adjusted sensitivity at 95% specificity ranking on par with the best assays submitted to the two most recent IASP workshops. In FDRs, the IAA LIPS showed improved discrimination of progressors to T1D compared to RBA. CONCLUSIONS: We established a novel high-performance non-radioactive IAA LIPS that might replace the current gold standard RBA and find wide application in the study of the IAA response in T1D.

The Role of Age and Excess Body Mass Index in Progression to Type 1 Diabetes in At-Risk Adults.

Background: Given the global rise in both type 1 diabetes incidence and obesity, the role of body mass index (BMI) on type 1 diabetes pathophysiology has gained great interest. Sustained excess BMI in pediatric participants of the TrialNet Pathway to Prevention (PTP) cohort increased risk for progression to type 1 diabetes, but the effects of age and obesity in adults remain largely unknown. Objective: To determine the effect of age and sustained obesity on the risk for type 1 diabetes in adult participants in the TrialNet PTP cohort (i.e., nondiabetic autoantibody-positive relatives of patients with type 1 diabetes). Research Design and Methods: Longitudinally accumulated BMI >25 kg/m2 was calculated to generate a cumulative excess BMI (ceBMI) for each participant, with ceBMI values ≥0 kg/m2 and ≥5 kg/m2 representing sustained overweight or obese status, respectively. Recursive partitioning analysis yielded sex- and age-specific thresholds for ceBMI that confer the greatest risk for type 1 diabetes progression. Results: In this cohort of 665 adults (age 20 to 50 years; median follow-up, 3.9 years), 49 participants developed type 1 diabetes. Age was an independent protective factor for type 1 diabetes progression (hazard ratio, 0.95; P = 0.008), with a threshold of >35 years that reduced risk for type 1 diabetes. In men age >35 years and women age <35 years, sustained obesity (ceBMI ≥5 kg/m2) increased the risk for type 1 diabetes. Conclusions: Age is an important factor for type 1 diabetes progression in adults and influences the impact of elevated BMI, indicating an interplay of excess weight, age, and sex in adult type 1 diabetes pathophysiology.

Diagnosis of insulin autoimmune syndrome using polyethylene glycol precipitation and gel filtration chromatography with ex vivo insulin exchange.

CONTEXT: Insulin-binding antibodies may produce severe dysglycaemia in insulin-naïve patients ('insulin autoimmune syndrome' (IAS) or Hirata disease), while rendering routine insulin assays unreliable. OBJECTIVE: To assess the performance of clinically used insulin assays and an optimal analytical approach in the context of IAS. DESIGN: Observational biochemical study of selected patients with hyperinsulinaemic hypoglycaemia. PATIENTS: Three patients without diabetes with recurrent spontaneous hyperinsulinaemic hypoglycaemia and 'positive' insulin antibodies. MEASUREMENTS: A panel of clinically used insulin assays (Siemens ADVIA® Centaur, Siemens Immulite® 2000, DiaSorin LIAISON® XL, PE AutoDELFIA® and the Beckman Coulter Access® 2) were used before and after plasma dilution or polyethylene glycol (PEG) precipitation. Anti-insulin IgG antibodies were measured by Isletest™ -IAA ELISA. Gel filtration chromatography (GFC) was undertaken with and without preincubation of plasma with exogenous insulin. RESULTS: Dilution of IAS plasma with assay-specific buffer increased insulin recovery, supporting negative immunoassay interference by antibodies. PEG precipitation of IAS plasma decreased insulin recovery using all assays except the Immulite® 2000. GFC discriminated high molecular weight and monomeric insulin, while ex vivo addition of exogenous insulin to plasma increased insulin bound to antibody, thereby improving the sensitivity of detection of insulin immunocomplexes. CONCLUSIONS: Immunoprecipitation with PEG must be used with caution in screening for insulin-antibody complexes as results are assay dependent. GFC with addition of exogenous insulin can identify significant insulin immunocomplexes with enhanced sensitivity, with attendant greater clinical utility and avoidance of radiolabelled reagents.

ECL-IAA and ECL-GADA Can Identify High-Risk Single Autoantibody-Positive Relatives in the TrialNet Pathway to Prevention Study.

BACKGROUND: Relatives with single positive islet autoantibodies have a much lower risk of progression to diabetes than those with multiple autoantibodies. MATERIALS AND METHODS: TrialNet subjects positive for single autoantibody to insulin (mIAA) (n = 50) or single autoantibody to glutamic acid decarboxylase (GADA) (n = 50) were analyzed using new electrochemiluminescence (ECL) assays (ECL-IAA and ECL-GADA, respectively) at their initial visit and longitudinally over time. Affinity assays were performed on a subset of single autoantibody-positive subjects at initial and most recent visits. RESULTS: After a mean follow-up of 5.3 years, 20 subjects developed type 1 diabetes. Among either single GADA or single mIAA subjects, those who were positive in the ECL assay showed higher affinity at the initial visit, and affinity results stayed consistent over time. No converting events from low to high or high to low affinity were seen over time. CONCLUSIONS: Confirmed positivity for ECL is associated with high affinity and can help staging of risk for type 1 diabetes in single autoantibody-positive subjects.

Evaluation of immunogenicity of LY2963016 insulin glargine compared with Lantus® insulin glargine in patients with type 1 or type 2 diabetes mellitus.

AIMS: To compare the immunogenicity profiles and the potential effects on clinical outcomes of LY2963016 insulin glargine (LY IGlar) and Lantus® insulin glargine (IGlar), products with identical primary amino acid sequences, in patients with type 1 or type 2 diabetes mellitus (T1DM or T2DM). METHODS: To assess immunogenicity, anti-insulin glargine antibodies (measured as percent binding) were compared between treatments in 52-week (open-label) and 24-week (double-blind) randomized studies in total study populations of patients with T1DM (N = 535) and T2DM (N = 756), respectively, and two subgroups of patients with T2DM: insulin-naïve patients and those reporting prestudy IGlar treatment (prior IGlar). Relationships between insulin antibody levels and clinical outcomes were assessed using analysis of covariance and partial correlations. Insulin antibody levels were assessed using Wilcoxon rank sum. Treatment comparisons for treatment-emergent antibody response (TEAR) and incidence of detectable antibodies were analysed using Fisher's exact test. RESULTS: No significant treatment differences were observed for insulin antibody levels, incidence of detectable anti-insulin glargine antibodies, or incidence of TEAR [overall and endpoint, by last-observation-carried-forward (LOCF)] in patients with T1DM or patients with T2DM, including the insulin-naïve subgroup. A statistically significant difference was noted in the overall incidence of detectable antibodies but not at endpoint (LOCF) nor in TEAR for the prior IGlar subgroup of patients with T2DM. Insulin antibody levels were low (<5%) in both treatment groups. Insulin antibody levels or developing TEAR was not associated with clinical outcomes. CONCLUSIONS: LY IGlar and IGlar have similar immunogenicity profiles; anti-insulin glargine antibody levels were low for both treatments, with no observed effect on efficacy and safety outcomes.

Use of Dried Capillary Blood Sampling for Islet Autoantibody Screening in Relatives: A Feasibility Study.

BACKGROUND: Islet autoantibody testing provides the basis for assessment of risk of progression to type 1 diabetes. We set out to determine the feasibility and acceptability of dried capillary blood spot-based screening to identify islet autoantibody-positive relatives potentially eligible for inclusion in prevention trials. MATERIALS AND METHODS: Dried blood spot (DBS) and venous samples were collected from 229 relatives participating in the TrialNet Pathway to Prevention Study. Both samples were tested for glutamic acid decarboxylase, islet antigen 2, and zinc transporter 8 autoantibodies, and venous samples were additionally tested for insulin autoantibodies and islet cell antibodies. We defined multiple autoantibody positive as two or more autoantibodies in venous serum and DBS screen positive if one or more autoantibodies were detected. Participant questionnaires compared the sample collection methods. RESULTS: Of 44 relatives who were multiple autoantibody positive in venous samples, 42 (95.5%) were DBS screen positive, and DBS accurately detected 145 of 147 autoantibody-negative relatives (98.6%). Capillary blood sampling was perceived as more painful than venous blood draw, but 60% of participants would prefer initial screening using home fingerstick with clinic visits only required if autoantibodies were found. CONCLUSIONS: Capillary blood sampling could facilitate screening for type 1 diabetes prevention studies.

Detection of insulitis by pancreatic scintigraphy with 99mTc-labeled IL-2 and MRI in patients with LADA (Action LADA 10).

OBJECTIVE: Pancreatic scintigraphy with interleukin-2 radiolabeled with (99m)Tc ((99m)Tc-IL-2) is a technique used to image chronic inflammatory-mediated disorders. We used this method to detect a signal consistent with the presence of insulitis in patients with autoimmune diabetes. Positive and negative controls (patients with pancreatic carcinoma and type 2 diabetes, respectively) also were studied. RESEARCH DESIGN AND METHODS: We examined 25 patients with autoimmune diabetes (16 with recently diagnosed type 1 diabetes, 9 with latent autoimmune diabetes in adults [LADA]), 6 with type 2 diabetes, and 7 with pancreatic carcinoma (the latter two groups were used as negative and positive controls, respectively). All patients underwent (99m)Tc-IL-2 scintigraphy and contrast-enhanced MRI of the pancreas. To validate positive controls, samples were taken from patients with pancreatic carcinoma during surgery for histological and immunohistochemical investigations. RESULTS: Pancreatic accumulation of (99m)Tc-IL-2 was detected in patients with autoimmune diabetes (61% positive) and, notably, in 6 of 9 patients with LADA; semiquantitative evaluation of pancreatic uptake of (99m)Tc-IL-2 showed higher values in patients with autoimmune diabetes (both childhood and LADA) and pancreatic carcinoma than in those with type 2 diabetes (4.45 ± 1.99, 4.79 ± 1.1, and 4.54 ± 1.62 vs. 2.81 ± 0.63; P = 0.06, P = 0.01, and P = 0.04, respectively). In patients with pancreatic carcinoma, pancreatic interleukin-2 receptor expression correlated with pancreatic (99m)Tc-IL-2 uptake (r = 0.8; P = 0.01). In patients with LADA, (99m)Tc-IL-2 uptake inversely correlated with duration of disease (r = 0.7; P = 0.03). CONCLUSIONS: Autoimmune diabetes in adults is associated with increased pancreatic (99m)Tc-IL-2 uptake, indicating the presence of insulitis, particularly within 1 year of the beginning of insulin therapy, similar to type 1 diabetes at diagnosis.

Impact of anti-insulin antibodies on islet transplantation outcome: data from the GRAGIL Network.

BACKGROUND: In patients with type 1 diabetes, insulin antibodies (IA), altering the pharmacokinetics of circulating insulin, might be associated with high glucose concentration, prolonged hypoglycemia, and higher insulin requirement. The impact of IA on islet transplantation has never been explored. Our aim was to evaluate islet transplantation results at 1 year according to the presence of IA. METHODS: Our work is a retrospective, case-control study, comparing IA-negative and IA-positive patients among the cohort of patients with type 1 diabetes transplanted within the Swiss-French GRAGIL network between 2003 and 2010. RESULTS: Data about IA were available for 17 patients. Before islet transplantation, 10 patients (59%) were screened positive for IA. At 12 months after transplantation, IA-positive patients reached insulin independence less frequently than IA-negative patients (cumulative incidence of insulin independence, 22.2% vs. 71.4%; P=0.02); ß score was ≥7 in 43% of IA-negative patients versus 0% in IA-positive patients (P=0.022). When comparing IA-positive patients with IA-negative patients, insulin dose was 0.15 U/kg (0.10-0.18 U/kg) versus 0.01 U/kg (0-0.09 U/kg) (P=0.2); HbA1c was 6.1% (5.8%-6.3%) versus 6.1% (5.9%-6.8%) (P=0.16); basal C-peptide level was 460 ρmol/L (350-510 ρmol/L) versus 265 ρmol/L (177-405 ρmol/L) (P=0.28); occurrence of hypoglycemia was 12.5% versus 16.5% (P=0.9); and homeostatic model assessment insulin resistance was 1.25 (1-2.4) versus 0.7 (0.52-0.92) (P=0.01). CONCLUSION: After islet transplantation, IA-positive patients achieved insulin independence less frequently, exhibiting lower ß score and higher homeostatic model assessment insulin resistance compared with IA-negative patients. However, in both groups, islet transplantation restored good glycemic control and drastically reduced hypoglycemia and insulin requirements.

Development of an ultra-sensitive enzyme immunoassay for human insulin autoantibodies.

OBJECTIVES: We developed an ultrasensitive enzyme immunoassay (ICT-EIA) for insulin autoantibody (IAA) measurements to better understand the pathophysiology of diabetes. DESIGN AND METHODS: We developed ICT-EIA for IAA and measured IAA in 24 patients with type 1 diabetes, 30 patients with type 2 diabetes, 30 patients with methimazole-treated Graves' disease, 20 patients with Hashimoto's disease, 9 patients with hyperinsulinemia, and 73 healthy control subjects. RESULTS: The conventional ELISA identified 3 patients with type 1 diabetes and 2 patients with type 2 diabetes as IAA positive, whereas 15 patients with type 1 diabetes, 7 patients with type 2 diabetes, and 4 patients with methimazole-treated Graves' disease were identified as IAA positive using ICT-EIA. CONCLUSIONS: The ICT-EIA is an ultrasensitive and specific assay for IAA, and its use may provide a better understanding of the role of IAA in diabetes onset and progression.

Distinguishing persistent insulin autoantibodies with differential risk: nonradioactive bivalent proinsulin/insulin autoantibody assay.

A subset of children develops persistent insulin autoantibodies (IAA; almost always as the only islet autoantibody) without evidence of progression to diabetes. The aim of the current study was the development and characterization of the performance of a nonradioactive fluid phase IAA assay in relation to standard IAA radioassay. We developed a nonradioactive IAA assay where bivalent IAA cross-link two insulin moieties in a fluid phase. The serum samples positive for anti-islet autoantibodies from 150 newly diagnosed patients with diabetes (Barbara Davis Center plus Diabetes Autoantibody Standardization Program [DASP] workshop) and 70 prediabetic subjects who were followed to diabetes were studied. In addition, sequential samples from 64 nondiabetic subjects who were persistently IAA(+) were analyzed. With 99th percentile of specificity, the new assay with the technology from Meso Scale Discovery Company (MSD-IAA) detects as positive 61% (61 of 100) of new-onset patients and 80% (56 of 70) of prediabetic patients compared with our current fluid phase micro-IAA radioassay (mIAA; 44 and 74%, respectively). In addition, MSD-IAA demonstrated better sensitivity than our mIAA from blinded DASP workshop (68 vs. 56% with the same 99% specificity). Of 64 IAA(+) nondiabetic subjects, 25% (8 of 32) who had only IAA and thus the low risk for progression to diabetes were positive with MSD-IAA assay. In contrast, 100% (32 of 32) high-risk children (IAA plus other islet autoantibodies) were positive with MSD-IAA. The IAA detectable by radioassay, but not MSD-IAA, were usually of lower affinity compared with the IAA of the high-risk children. These data suggest that a subset of IAA with current radioassay (not MSD-IAA) represents biologic false positives in terms of autoimmunity leading to diabetes. We hypothesize that factors related to the mechanism of loss of tolerance leading to diabetes determine high affinity and MSD-IAA reactivity.

Interaction of enterovirus infection and cow's milk-based formula nutrition in type 1 diabetes-associated autoimmunity.

BACKGROUND: Enteral virus infections and early introduction of cow's milk (CM)-based formula are among the suggested triggers of type 1 diabetes (T1D)-associated autoimmunity, although studies on their role have remained contradictory. Here, we aimed to analyse whether interactions between these factors might clarify the controversies. MATERIALS: The study population comprised 107 subjects developing positivity for at least two T1D-associated autoantibodies and 446 control subjects from the Finnish diabetes prediction and prevention cohort. Enterovirus, rotavirus, adenovirus, respiratory syncytial virus and bovine insulin-binding antibodies were analysed from prospective serum samples at 3-24 months of age. Data on infant cow's milk exposure were available for 472 subjects: 251 subjects were exposed to cow's milk before 3 months of age and 221 subjects later in infancy. RESULTS: Signs of an enterovirus infection by 12 months of age were associated with the appearance of autoimmunity among children who were exposed to cow's milk before 3 months of age. Cox regression analysis revealed a combined effect of enterovirus infection and early cow's milk exposure for the development of ICA and any of the biochemically defined autoantibodies (p = 0.001), of IAA (p = 0.002), GADA (p = 0.001) and IA-2A (p = 0.013). CONCLUSIONS: The effect of enterovirus infection on the appearance of T1D-associated autoimmunity seems to be modified by exposure to cow's milk in early infancy suggesting an interaction between these factors. Moreover, these results provide an explanation for the controversial findings obtained when analysing the effect of any single one of these factors on the appearance of T1D-associated autoimmunity.

Role of beta-cell autoantibodies as a predictor marker in diabetic patients and their relationship to glycemic control.

To evaluate glutamic acid decarboxylase autoantibodies (GAD65), islet cell autoantibodies (ICA) and insulin autoantibodies (IAA) as disease markers and their relationship to certain residual beta-cell function as well as glycemic control among patients with diabetes mellitus. Also, to evaluate of the level of CD4+CD25+(Treg) out of CD4 cells among patients with immune mediated diabetes mellitus (DM). The study included 80 individuals divided into: 40 diabetic patients (group A) and 20 risk siblings (group B) of diabetic father or mother or both. 20 healthy individuals enrolled as control group (group C) all were with no family history of DM. GAD, ICA, IAA autoantibodies and C-peptide were determined by ELISA. HbA1 by ion exchange chromatography and measurement of the expression of CD4+CD25+ (T reg) by flowcytometry. The most frequently encountered antibody in adult and children groups was GAD65, followed by ICA. But in risk group the most frequently antibody was ICA, followed by GAD. In the risk group, there was no statistical difference in the level of CD4+CD25+ in comparison with control group. There was significant decrease in the percentage of CD4+CD25+ in adult and children patients groups with positive autoantibodies than those with negative autoantibodies. In conclusions, at the time of diagnosis the majority of patients with type I diabetes have autoantibodies that are reactive to islet antigens. GAD, ICA, IAA are of value for predicting IDDM in sibling of diabetic parents type I. CD4+CD25+ Treg cells may actively suppress activation of the immune system and prevent pathological self-reactivity.