Prevalence of autoantibody-negative diabetes is not rare at all ages and increases with older age and obesity

Approach to the obese adolescent with new-onset diabetes

The prevalence of both type 1 and type 2 diabetes among children and adolescents has been steadily increasing over the last few decades. However, as the general pediatric population becomes more obese and more ethnically diverse, reliance on phenotypic characteristics for distinguishing between these types of diabetes is becoming increasingly untenable. Yet, the recognition of differences in treatment strategies, associated disorders, and both short- and long-term diabetes and cardiovascular outcomes supports the importance of diagnostic efforts to make a distinction between diabetes types. An approach to determination of diabetes type is discussed, focused on the presence or absence of autoimmunity and assessment of β-cell function. At the time of diagnosis, it is generally not possible to be certain of diabetes type, and therefore, initial treatment decisions must be made based on aspects of the presenting physiology, with adjustments in treatment approach made as the individual's course proceeds and additional information becomes available. The apparent overlap between type 1 and type 2 diabetes that occurs in obese adolescents has resulted in some controversy regarding mixed forms of diabetes that are ultimately semantic, but this does raise interesting questions about the treatment of type 1 diabetes in the presence of an insulin-resistant phenotype. Finally, the lack of information about the efficacy of treatment of cardiovascular risk factors, such as dyslipidemia and hypertension, along with the well-documented challenges in adherence to chronic illness treatment in this population, creates substantial challenges.

Polyendocrinopathy in children, adolescents, and young adults with type 1 diabetes: a multicenter analysis of 28,671 patients from the German/Austrian DPV-Wiss database

OBJECTIVE

To investigate diabetes-specific autoantibodies and additional autoimmune phenomena in a large cohort of young patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Data from 28,671 patients <30 years with type 1 diabetes from 242 specialized centers in Germany and Austria were analyzed.

RESULTS

At least one beta-cell antibody was present in 81.6% of patients. beta-cell-Ab-negative patients were significantly younger at diabetes onset (P < 0.0001). A total of 19.6% had positive thyroid antibodies with female predominance (62%, P < 0.0001). Antibodies to tissue transglutaminase were present in 10.7%, with a significantly longer duration of diabetes (P < 0.0001). Parietal cell antibodies were found in 283 patients, associated with older age (P < 0.001), and adrenal antibodies were present in 94 patients. In 575 patients, at least three different autoimmune phenomena were present.

CONCLUSIONS

Thyroid autoimmunity and antibodies suggestive for celiac disease are the most prevalent additional immune phenomena in type 1 diabetes. Parietal/adrenal antibodies are rare.

Multidisciplinary management of type 2 diabetes in children and adolescents

Although once considered a disease of adults, the prevalence of type 2 diabetes in youth is increasing at a significant rate. Similar to adults, youth with type 2 diabetes are at increased risk for developing hypertension, lipid abnormalities, renal disease, and other diabetes-related complications. However, children and adolescents with type 2 diabetes also face many unique management challenges that are different from adults with type 2 diabetes or children with type 1 diabetes. To deliver safe, effective, high-quality, cost-effective health care to adolescents with type 2 diabetes, reorganization and redesign of health care systems are needed. Multidisciplinary health care teams, which allow individuals with specialized training to maximally utilize their skills within an organized diabetes treatment team, may increase efficiency and effectiveness and may improve outcomes in children with type 2 diabetes. This review article provides a brief review of type 2 diabetes in children and adolescents, provides an overview of multidisciplinary health care teams, and discusses the role of multidisciplinary health care management in youth with type 2 diabetes.

Dimorphic histopathology of long-standing childhood-onset diabetes

AIMS/HYPOTHESIS

Childhood diabetes is thought to usually result from autoimmune beta cell destruction (type 1A) with eventual total loss of beta cells. Analysis of C-peptide in children characterised at diabetes onset for autoantibodies shows heterogeneous preservation of insulin secretion in long-standing diabetes. The aim of this study was to characterise the pancreases of childhood-onset diabetes in order to define the pathological basis of this heterogeneity.

METHODS

We evaluated 20 cadaveric organ donor pancreases of childhood-onset long-term patients for disease heterogeneity and obtained corresponding C-peptide measurements.

RESULTS

Pancreases from the majority of cadaveric donors contained only insulin-deficient islets (14 of 20). The remaining six patients (30%) had numerous insulin-positive cells within at least some islets, with two different histological patterns. Pattern A (which we would associate with type 1A diabetes) had lobular retention of areas with 'abnormal' beta cells producing the apoptosis inhibitor survivin and HLA class I. In pattern B, 100% of all islets contained normal-appearing but quantitatively reduced beta cells without survivin or HLA class I.

CONCLUSIONS/INTERPRETATION

Our data demonstrate that C-peptide secretion in long-standing diabetic patients can be explained by two different patterns of beta cell survival,possibly reflecting different subsets of type 1 diabetes.

Banting Lecture 2009: An unfinished journey: molecular pathogenesis to prevention of type 1A diabetes

The Banting Medal for Scientific Achievement Award is the American Diabetes Association's highest scientific award and honors an individual who has made significant, long-term contributions to the understanding of diabetes, its treatment, and/or prevention. The award is named after Nobel Prize winner Sir Frederick Banting, who codiscovered insulin treatment for diabetes.

Dr. Eisenbarth received the American Diabetes Association's Banting Medal for Scientific Achievement at the Association's 69th Scientific Sessions, June 5–9, 2009, in New Orleans, Louisiana. He presented the Banting Lecture, An Unfinished Journey—Type 1 Diabetes—Molecular Pathogenesis to Prevention , on Sunday, June 7, 2009.

Attacking the source: anti-PDX-1 responses in type 1 diabetes

Type 1 diabetes (T1D) develops as a consequence of abnormal responses against several self-antigens, eventually leading to the autoimmune attack and destruction of the insulin-producing beta cells in the pancreas. In this issue of Laboratory Investigation, Li et al propose the transcription factor Pancreatic and duodenal homeobox 1 (PDX-1) as a T1D autoantigen by demonstrating autoreactivity to this pancreas-specific protein in both the NOD mouse model and patients with T1D. Because of the known roles of PDX-1 in pancreatic development as well as beta cell maintenance and function, targeting of PDX-1 expressing cells may result in the elimination of not only beta cells but also the progenitor cells required for regeneration of insulin-producing cells.

Early over expression of messenger RNA for multiple genes, including insulin, in the Pancreatic Lymph Nodes of NOD mice is associated with Islet Autoimmunity

BACKGROUND

Autoimmune diabetes (T1D) onset is preceded by a long inflammatory process directed against the insulin-secreting beta cells of the pancreas. Deciphering the early autoimmune mechanisms represents a challenge due to the absence of clinical signs at early disease stages. The aim of this study was to identify genes implicated in the early steps of the autoimmune process, prior to inflammation, in T1D. We have previously established that insulin autoantibodies (E-IAA) predict early diabetes onset delineating an early phenotypic check point (window 1) in disease pathogenesis. We used this sub-phenotype and applied differential gene expression analysis in the pancreatic lymph nodes (PLN) of 5 weeks old Non Obese Diabetic (NOD) mice differing solely upon the presence or absence of E-IAA. Analysis of gene expression profiles has the potential to provide a global understanding of the disease and to generate novel hypothesis concerning the initiation of the autoimmune process.

METHODS

Animals have been screened weekly for the presence of E-IAA between 3 and 5 weeks of age. E-IAA positive or negative NOD mice at least twice were selected and RNAs isolated from the PLN were used for microarray analysis. Comparison of transcriptional profiles between positive and negative animals and functional annotations of the resulting differentially expressed genes, using software together with manual literature data mining, have been performed.

RESULTS

The expression of 165 genes was modulated between E-IAA positive and negative PLN. In particular, genes coding for insulin and for proteins known to be implicated in tissue remodelling and Th1 immunity have been found to be highly differentially expressed. Forty one genes showed over 5 fold differences between the two sets of samples and 30 code for extracellular proteins. This class of proteins represents potential diagnostic markers and drug targets for T1D.

CONCLUSION

Our data strongly suggest that the immune related mechanisms taking place at this early age in the PLN, correlate with homeostatic changes influencing tissue integrity of the adjacent pancreatic tissue. Functional analysis of the identified genes suggested that similar mechanisms might be operating during pre-inflammatory processes deployed in tissues i) hosting parasitic microorganisms and ii) experiencing unrestricted invasion by tumour cells.

Testing for monogenic diabetes among children and adolescents with antibody-negative clinically defined Type 1 diabetes

AIMS

Monogenic diabetes is frequently misdiagnosed as Type 1 diabetes. We aimed to screen for undiagnosed monogenic diabetes in a cohort of children who had a clinical diagnosis of Type 1 diabetes but were pancreatic autoantibody-negative.

METHODS

We studied 252 patients diagnosed clinically with Type 1 diabetes between 6 months and 17 years of age. Pancreatic autoantibodies [islet cell autoantibodies (ICA), glutamic acid decarboxylase antibodies (GADA) and/or insulinoma-associated antigen-2 antibodies (IA2A)] were absent in 25 cases (9.9%). The most frequent genes involved in monogenic diabetes [KCNJ11 and INS for neonatal diabetes and HNF1A and HNF4A for maturity-onset diabetes of the young (MODY)] were directly sequenced.

RESULTS

Two of the 25 (8%) antibody-negative patients had de novo heterozygous mutations in INS; c.94G>A (G32S) and c.265C>T (R89C). The two patients presented with non-ketotic hyperglycaemia at 8 and 11 months of age. In contrast, the four antibody-positive patients who presented at a similar age (6-12 months) had a more severe metabolic derangement, manifested as ketosis in all four cases, with ketoacidosis in two. At ages 15 and 5 years, both INS mutation patients were prescribed a replacement dose of insulin with good glycaemic control [glycated haemoglobin (HbA(1c)) 7.0 and 7.2%]. No mutations were found in KCNJ11, HNF1A or HNF4A.

CONCLUSIONS

The identification of patients with monogenic diabetes from children with clinically defined Type 1 diabetes may be helped by clinical criteria including the absence of pancreatic autoantibodies.

Relation of obesity to consummatory and anticipatory food reward

This report reviews findings from studies that have investigated whether abnormalities in reward from food intake and anticipated food intake increase risk for obesity. Self-report and behavioral data suggest that obese relative to lean individuals show elevated anticipatory and consummatory food reward. Brain imaging studies suggest that obese relative to lean individuals show greater activation of the gustatory cortex (insula/frontal operculum) and oral somatosensory regions (parietal operculum and Rolandic operculum) in response to anticipated intake and consumption of palatable foods. Yet, data also suggest that obese relative to lean individuals show less activation in the dorsal striatum in response to consumption of palatable foods and reduced striatal D2 dopamine receptor density. Emerging prospective data also suggest that abnormal activation in these brain regions increases risk for future weight gain and that genotypes associated with lowered dopamine signaling amplify these predictive effects. Results imply that individuals who show greater activation in the gustatory cortex and somatosensory regions in response to anticipation and consumption of food, but who show weaker activation in the striatum during food intake, may be at risk for overeating, particularly those at genetic risk for lowered dopamine receptor signaling.

Update on nonautoimmune diabetes in children

Over the last two decades, nonautoimmune-mediated type 2 diabetes mellitus (T2DM) has become a clinical entity of increasing importance among adolescents. Yet, research specific to adolescent T2DM is in its infancy. Our understanding of the epidemiology of T2DM among adolescents is complicated by variability in definition, incomplete knowledge of novel autoimmune epitopes, the presence of individuals with phenotypic overlap between type 1 and type 2 diabetes, and inadequate understanding of the contribution of common single-gene defects. Furthermore, a higher ratio of diagnosed to undiagnosed cases and a strong relationship with the onset of puberty suggest unique aspects of the pathophysiology in adolescents. Investigators have begun to address these areas while also identifying important relationships with the intrauterine development. Well-designed clinical studies are currently examining the adolescent-specific challenges in prevention and treatment of T2DM, whereas a number of associations struggle to provide screening and treatment guidelines to practitioners based on limited understanding of the phenomenon. Finally, there is growing understanding of medium- and long-term morbidity and mortality in early adulthood. Given the likelihood that early-onset T2DM will have important implications for future public health, continued attention to all aspects of this complex social, economic, and physiological disorder is critical.

The TrialNet Natural History Study of the Development of Type 1 Diabetes: objectives, design, and initial results

OBJECTIVES

TrialNet's goal to test preventions for type 1 diabetes has created an opportunity to gain new insights into the natural history of pre-type 1 diabetes. The TrialNet Natural History Study (NHS) will assess the predictive value of existing and novel risk markers for type 1 diabetes and will find subjects for prevention trials.

RESEARCH DESIGN AND METHODS

The NHS is a three-phase, prospective cohort study. In phase 1 (screening), pancreatic autoantibodies (glutamic acid decarboxylase, insulin, ICA-512, and islet cell antibodies) are measured. Phase 2 (baseline risk assessment) includes oral glucose tolerance tests (OGTTs) in antibody-positive subjects and estimation of 5-yr diabetes risks according to the OGTT and number of confirmed positive antibody tests. Phase 3 (follow-up risk assessments) requires OGTTs every 6 months. In phases 2 and 3, samples are collected for future tests of T-lymphocyte function, autoantibody isotypes, RNA gene expression, and proteomics. The primary outcome is diabetes onset.

RESULTS

Of 12 636 relatives screened between March 2004 and December 2006, 605 (4.8%) were positive for at least one biochemical antibody. Of these, 322 were confirmed antibody positive and completed phase 2, of whom 296 subjects were given preliminary 5-yr diabetes risks of <25% (n = 132), > or =25% (n = 36), and > or =50% (n = 128) where the latter two categories represent different subjects based on number of confirmed positive antibodies (2, > or =25%; 3 or more, > or =50%) and/or an abnormal OGTT (> or =50%).

CONCLUSIONS

The NHS is identifying potential prevention trial subjects and is assembling a large cohort that will provide new natural history information about pre-type 1 diabetes. Follow-up to diabetes will help establish the biological significance and clinical value of novel type 1 diabetes risk markers.

Improved T cell assay for identification of type 1 diabetes patients

Diabetes mellitus is comprised primarily of two clinically separate diseases: type 1 (T1D) and type 2 diabetes (T2D). T1D is a cell-mediated autoimmune disease directed against the beta cells and characterized by autoantibody (Ab) and T cell reactivity to islet proteins whereas, T2D is non-autoimmune. Despite the fact that the pathological process in autoimmune diabetes involves T cells, immune markers of diabetes have primarily centered on the presence of circulating serum islet autoantibodies. In two masked NIH sponsored workshops, our cellular immunoblotting T cell assay, which uses isolated human islets separated into 18 molecular weight fractions, has been validated to be able to distinguish T1D patients from controls with excellent specificity and sensitivity. In this study, we utilized the first workshop to select eight molecular weight fractions of human islets that were the most discriminatory between T1D patients and controls. Using these eight molecular weight fractions identified in the first workshop, we validated the preferential recognition of these 8 blot sections in a second workshop. We then re-calculated the sensitivity and specificity of the cellular immunoblotting assay for both workshops using only the data from these 8 blot sections.We observed increases in both sensitivity and specificity compared to the original workshop data for both workshops. The use of 8 instead of 18 molecular weight regions allows for a significant reduction in the amount of blood needed from patients, thus allowing cellular immunoblotting to be performed on pediatric patients participating in immunomodulatory studies. This improved T cell assay, which directly measures islet reactive T cell responses in autoimmune diabetes patients with excellent sensitivity and specificity, will likely improve patient follow-up during intervention studies.

Single nucleotide transcription factor 7-like 2 (TCF7L2) gene polymorphisms in antiislet autoantibody-negative patients at onset of diabetes

CONTEXT

There is controversy as to whether type 2 diabetes genetic susceptibility contributes to type 1 diabetes, and it is not known what proportion of islet autoantibody-negative new onset subjects have type 2 diabetes risk alleles.

OBJECTIVES

We designed this study to evaluate whether two type 2 diabetes-associated single nucleotide polymorphisms (SNPs) of transcription factor 7-like 2 (TCF7L2) gene are associated with the development of islet autoantibody-negative diabetes vs. islet autoantibody-positive diabetes in young patients and whether these SNPs are associated with specific clinical phenotypes.

DESIGN

Autoantibody against glutamic acid decarboxylase 65, islet cell antibody 512bdc (form of IA-2), insulin, ZnT8 transporter, and cytoplasmic islet cell antibody were assayed in patients with new onset diabetes seen at the Barbara Davis Center using sera obtained within 2 wk of diagnosis. We genotyped two noncoding variants in the TCF7L2 gene, rs12255372 and rs7903146, in diabetic subjects and normal controls.

RESULTS

A total of 140 patients (15.7%) were negative for all islet autoantibodies among 893 subjects less than age 25 at the onset of diabetes. The allele and genotype frequencies of two SNPs showed that these are associated (odds ratio up to 4) with the development of diabetes in the autoantibody-negative diabetic cohort, but not in the autoantibody-positive diabetic cohort.

CONCLUSION

TCF7L2 type 2 diabetes susceptibility alleles are associated with islet autoantibody-negative but not autoantibody-positive new onset diabetes in young patients.

New-onset diabetes in an obese adolescent: diagnostic dilemmas

BACKGROUND

A 14-year-old, obese, African American boy presented to his pediatrician with polyuria, polydipsia, and a significant unintentional weight loss. He was dehydrated, with high levels of blood sugar and urinary ketones. He had no history of previous illnesses and was not taking any medications. He had a family history of type 2 diabetes mellitus.

INVESTIGATIONS

Physical examination included assessing stigmata of insulin resistance, and measuring blood pressure, pulse, and BMI. Blood samples were obtained for measurement of venous blood pH, bicarbonate, serum glucose, electrolytes, HbA(1C), aminotransferases and lipids. Urine was sampled for measurement of ketones. Subsequently, measurements of fasting C-peptide and immunoassays for insulin autoantibodies (IAA), islet-cell autoantibodies (ICA-512) and glutamic acid decarboxylase autoantibodies (GAD-65) were performed.

DIAGNOSIS

New-onset diabetes mellitus with diabetic ketoacidosis, initially diagnosed as type 2 diabetes mellitus, but later determined as type 1 diabetes mellitus.

MANAGEMENT

After treatment of diabetic ketoacidosis with hydration and insulin infusion, the patient was discharged on subcutaneous insulin. He was diagnosed with type 2 diabetes mellitus and was transferred to oral insulin-sensitizing agents. He re-presented 18 months later with an insulin requirement during an asthma exacerbation treated with steroids. Due to the worsening of his diabetic symptoms, the patient was tested for islet autoantibodies and was found to be positive for GAD-65 and IAA, that is, diagnostic of type 1 diabetes mellitus. He has continued to require subcutaneous insulin.

Prolonged honeymoon phase in an adolescent with diabetes and thyrotoxicosis provides support for the accelerator hypothesis

A 14-yr-old female presented with diabetes and Graves' disease. Eighteen months later, she was euthyroid on carbimazole, and her haemoglobin A1c (HbA1c) was normal (5.2%) on a small insulin dose (0.3-0.4 units/kg/day). An assessment of her pancreatic beta-cell reserve, determined by comparing HbA1c and insulin dose, suggested that this was greater than other patients with type 1 diabetes in our service 18 months postdiagnosis (n = 185). We suspect that excess thyroid hormone led to an insulin-resistant state and accelerated her presentation with hyperglycaemia. Insulin resistance fell once normal thyroid function was restored and helped to attenuate further beta-cell destruction when beta-cell mass was relatively well preserved.

HLA class II alleles specify phenotypes of ketosis-prone diabetes

OBJECTIVE

Ketosis-prone diabetes (KPD) comprises four subgroups based on the presence or absence of beta-cell autoantibodies (A+ or A-) and beta-cell functional reserve (beta+ or beta-). Genetic factors could contribute to their distinctive phenotypes. Our aim was to specify the role of HLA class II alleles associated with susceptibility or resistance to autoimmune type 1 diabetes in determining KPD phenotypes.

RESEARCH DESIGN AND METHODS

A total of 185 adults presenting with diabetic ketoacidosis were followed longitudinally for a mean of 5.5 years, with measurements of autoantibodies, beta-cell functional reserve, insulin sensitivity, and insulin requirement. Frequencies of susceptibility and resistance alleles at HLA DQA1, DQB1, and DRB1 loci were correlated with clinical and phenotypic features of KPD subgroups and compared with those of ethnic-specific population control subjects.

RESULTS

Susceptibility alleles were more frequent (P < 0.0001) in the two A+ than the two A- KPD subgroups; in the latter, the frequency was no greater than in population control subjects (except for DQB1*0302). Susceptibility alleles differentiated the two clinically similar beta- subgroups (more frequent in A+beta- than A-beta- KPD; P < 0.01). Resistance alleles were more frequent in the two beta+ than the two beta- KPD subgroups (P < 0.01). The frequencies of certain susceptibility (e.g., DQB1*02) and resistance (DQB1*0602) alleles were higher in African-American A-beta+ KPD patients than in African-American control subjects. DQB1*0302 was more frequent in all KPD subgroups compared with control subjects.

CONCLUSIONS

HLA class II alleles associated with susceptibility or resistance to autoimmune type 1 diabetes help specify the four subgroups of KPD. Inheritance of these alleles may influence long-term beta-cell functional reserve.

Changed presentation of Hashimoto's thyroiditis in North-Eastern Sicily and Calabria (Southern Italy) based on a 31-year experience

OBJECTIVE

To quantify the yearly prevalence of Hashimoto's thyroiditis at our Division and evaluate changes in its clinical presentation over the period 1975-2005.

DESIGN

We have reviewed retrospectively the clinical records of patients admitted to a university hospital located in Messina, Sicily (Italy), from January 1, 1975, through December 31, 2005. This facility attracts patients from North-Eastern Sicily and most of Calabria, the Italian region across the Straits. HT was diagnosed based on various combinations of clinical, laboratory, and instrumental findings. The study group consisted of 4064 HT patients diagnosed during these 31 years.

MAIN OUTCOME

We evaluated these indexes on a yearly basis: number of new HT diagnoses; age at presentation; male-to-female ratio; functional status; goitrous or nongoitrous variants with or without nodule(s); above-normal titers or levels of serum thyroid autoantibodies (thyroglobulin antibodies and thyroperoxidase antibodies). Several indexes have changed over those 31 years. Particularly, HT has become 10 times more common than it was until the early 1990s and males are relatively more represented. Patients are relatively younger, with a nongoitrous thyroid; the rate of S-Hypo exceeds largely the rate of O-Hypo. Serum thyroid autoantibodies have become less frequently positive, and when positive, they are present at a lower concentration.

CONCLUSIONS

Only environmental changes, as opposed to genetic changes, can account for such alterations in the presentation of HT in our geographical area.

The natural history of type 1A diabetes

We can now predict the development of Type 1A (Immune Mediated) diabetes primarily through the determination of four biochemically characterized islet autoantibodies [insulin, GAD65, IA-2 (ICA512) and (Znt8)]. Prediction is possible because beta-cell destruction is chronically progressive and very slow in most, but not all individuals. We can also prevent type 1A diabetes in animal models and a major goal is the prevention of type 1A diabetes in man with multiple clinical trials underway.

[Heterogeneity of type 1 diabetes mellitus]

Type 1 diabetes (T1D) comprises all forms of autoimmune-mediated and idiopathic beta-cell destruction leading to absolute insulin deficiency. The etiological heterogeneity of T1D has been recognized for the last decades, but it has been divided into only two subtypes so far: autoimmune (T1D)A and non-autoimmune (T1D)B mediated. Polygenic T1DA (isolated or associated to other autoimmune diseases) is the most prevalent type of T1D. T1DA might be part of rare monogenic syndromes related to mutations in the autoimmune regulator gene (AIRE) and FOXp3. Non-autoimmune forms of T1D correspond to approximately 4 to 7% of newly diagnosed T1D and include T1DB, as well as other types of atypical diabetes, for example fulminant type 1 diabetes and adult ketosis-prone diabetes. A new expression of diabetes in young with insulin resistance and obesity, along with the presence of pancreatic autoimmunity markers, namely auto-antibodies to islet cell antigens, is called double diabetes (DD), T1DA plus type 2 diabetes. Evidence has been collected concerning the potential effect of obesity-linked cytokines in amplifying the autoimmune response in DD. Therefore all these issues are presented and discussed in this review as the concept of heterogeneity of Type 1 Diabetes.

Seasonality of month of birth differs between type 1 diabetes patients with pronounced beta-cell autoimmunity and individuals with lesser or no beta-cell autoimmunity

OBJECTIVE

To establish whether children with type 1 diabetes mellitus (T1D) with signs of pronounced beta-cell-specific autoimmunity as reflected by high autoantibody titers or positivity for several beta-cell-specific autoantibodies show a different pattern of month of birth (MOB) compared with children with T1D and low beta-cell autoimmunity and that of the general population.

RESEARCH DESIGN AND METHODS

Cosinor analysis was used to analyze MOB rhythmicity in Swedish children with new onset T1D (n = 572), in whom the glutamate decarboxylase autoantibody (GAD65Ab) titer was determined and compared with that in 833 healthy children, and in 505 children with T1D in Berlin, in whom the titers of autoantibodies to insulin, GAD65, and islet antigen-2 were compared with the MOB pattern in the general population (n = 446 571).

RESULTS

In both cohorts of children with T1D, we found that children with either a high GAD65Ab titer (above the 80th percentile) or positivity for three beta-cell-specific autoantibodies differed in their pattern of MOB from the healthy population.

CONCLUSIONS

Our past and present observations support the hypothesis that the autoimmune process leading to childhood T1D is in part triggered in the perinatal period by viral infections in genetically susceptible individuals. The present study suggests that the process is linked to titer levels of autoantibodies.

The cation efflux transporter ZnT8 (Slc30A8) is a major autoantigen in human type 1 diabetes

Type 1 diabetes (T1D) results from progressive loss of pancreatic islet mass through autoimmunity targeted at a diverse, yet limited, series of molecules that are expressed in the pancreatic beta cell. Identification of these molecular targets provides insight into the pathogenic process, diagnostic assays, and potential therapeutic agents. Autoantigen candidates were identified from microarray expression profiling of human and rodent pancreas and islet cells and screened with radioimmunoprecipitation assays using new-onset T1D and prediabetic sera. A high-ranking candidate, the zinc transporter ZnT8 (Slc30A8), was targeted by autoantibodies in 60-80% of new-onset T1D compared with <2% of controls and <3% type 2 diabetic and in up to 30% of patients with other autoimmune disorders with a T1D association. ZnT8 antibodies (ZnTA) were found in 26% of T1D subjects classified as autoantibody-negative on the basis of existing markers [glutamate decarboxylase (GADA), protein tyrosine phosphatase IA2 (IA2A), antibodies to insulin (IAA), and islet cytoplasmic autoantibodies (ICA)]. Individuals followed from birth to T1D showed ZnT8A as early as 2 years of age and increasing levels and prevalence persisting to disease onset. ZnT8A generally emerged later than GADA and IAA in prediabetes, although not in a strict order. The combined measurement of ZnT8A, GADA, IA2A, and IAA raised autoimmunity detection rates to 98% at disease onset, a level that approaches that needed to detect prediabetes in a general pediatric population. The combination of bioinformatics and molecular engineering used here will potentially generate other diabetes autoimmunity markers and is also broadly applicable to other autoimmune disorders.

Update in type 1 diabetes

CONTEXT

Type 1 diabetes is a heterogeneous disorder characterized by severe beta-cell loss. The great majority of patients have type 1A or immune-mediated diabetes.

SYNTHESIS

There has been recent progress in defining the genetics, pathogenesis, and natural history of the disease. In addition, there is a major effort to develop immunotherapies to prevent the disorder and to cure the disease with islet transplantation, and there is potential for dramatic improvement in care with introduction of continuous glucose monitoring devices. The discovery of "metabolic memory" underscores the importance of excellent metabolic control. With comprehensive care, major microvascular complications (e.g. blindness and renal failure) are preventable for most patients.

CONCLUSION

The existence of multiple "competing" technologies to deal with this devastating disorder holds promise of improved outcomes.