Latent Autoimmune Diabetes Of The Adult Research Articles

Utility of Fasting C-Peptide for the Diagnostic Differentiation of Patients with Type 1, Type 2 Diabetes, MODY, and LADA.

The prevalence of obesity has increased in patients with type 1 diabetes (T1D) and latent autoimmune diabetes of the adult (LADA), limiting the use of clinical features such as the body mass index for its differentiation with type 2 diabetes (T2D). Additionally, some patients with maturity-onset diabetes of the young (MODY) or LADA are misdiagnosed as having T2D. The evaluation of autoantibodies and genetic testing are not fully available. We aimed to evaluate the utility of a widely available and less expensive diagnostic tool such as C-peptide to differentiate between T1D, T2D, MODY, and LADA. Our study included 38 patients with T1D, 49 with T2D, 13 with MODY, and 61 with LADA. We recorded anthropometric measurements, biochemical profiles, and antidiabetic treatment and determined C-peptide, anti-GAD65, and anti-IA2 antibodies. C-peptide concentration differed significantly among populations (T1D: 0.2 ng/mL; T2D: 2.4 ng/mL; MODY: 1.14 ng/mL; LADA: 1.87 ng/mL). Through a ROC curve, we observed that the C-peptide cut-off point of 0.95 ng/mL allows differentiation between T1D and T2D (sensitivity 82%, specificity 77%); 0.82 ng/mL between T1D and LADA (sensitivity 82%, specificity 77%); and 1.65 ng/mL between T2D and MODY (sensitivity 72%, specificity 72%). C-peptide is useful for the diagnostic differentiation of patients with type 1, type 2 diabetes, MODY, and LADA.

1332-P: Comparison of Clinical Characteristics of People Living with Latent Autoimmune Diabetes of the Adult (LADA) and Type 1 Diabetes (T1D) in the Canadian BETTER Registry

Introduction: LADA is known for a slow progression of autoimmune destruction of beta-cells with cases that span a spectrum between classic T1D and T2D phenotypes. To date, lacking a good understanding of LADA has prohibited the release of specific clinical practice guidelines and subsequently an optimal management. Methodology: Cross-sectional analysis of online clinical questionnaires in the Canadian BETTER registry; participants can specify having received a diagnosis of LADA or T1D. Data was analyzed for the first 1464 participants; 131 (9%) reported LADA and 1333 (91%) T1D. Results: At registration; LADA vs T1D were 49 ± 13 y.o. vs 42 ± 15 y.o; 61% vs. 62% females; diabetes duration 10 ± 9 vs. 24 ± 15 years. LADA vs. T1D were older at diagnosis (39 ± 12 vs. 18 ± 12 years old; p<0.001), only half started insulin in first year of diagnosis (52 vs. 97%; p<0.001), more often reported a family history of T1D (46 vs. 32%; p=0.001). For comparable glycemic control (HbA1c < 8.6 mmol/l, <7%, 38 vs. 32%), fewer cases with LADA reported at least an episode in last month of level II hypoglycemia <54 mg/dL (3.0mmol/L) 63% vs. 77%; p= 0.004, severe hypoglycemia rates were 8% vs. 12%, p=0.15. Diabetes related hospitalizations were 10% in LADA vs. 6%, p=0.11, insulin pumps and glucagon were less used in LADA. In a matched analysis for diabetes duration and gender (1:1), glycemic control was still statistically comparable in LADA vs. T1D (HbA1c <7%: 38 vs 35%, p=0.12) as well as rates of nephropathy (6% vs. 11%, p=0.22), neuropathy (12% vs. 7%, p=0.23) and retinopathy (6% vs. 9%, p=0.07) yet with more cardiovascular disease (5% vs. 2%; p=0.02) and less coeliac disease (3 vs. 5%; p=0.001). Data analysis of 3000 participants is ongoing in early 2023. Conclusion: Reported differences may impact LADA management. This study sets the stage for building a prospective Canadian cohort of LADA to undergo deep phenotyping, genotyping and interventional trials. Disclosure M.Issa: None. A.Brazeau: Other Relationship; Dexcom, Inc., Diabète québec, Ordre des diététistes nutritionnistes du Québec, Research Support; Canadian Institutes of Health Research, Fonds de recherche du Québec en Santé. S.Haag: Other Relationship; Omnipod. A.Roy-fleming: None. V.Messier: None. N.Taleb: Consultant; Viatris Inc.

Masqueraders: how to identify atypical diabetes in primary care

Diabetes mellitus is a complex set of conditions that impacts 34 million Americans. While type 1 diabetes, type 2 diabetes, and gestational diabetes are most frequently encountered, there are many other types of diabetes with which healthcare providers are less familiar. These atypical forms of diabetes make up nearly 10% of diabetes cases and can masquerade as type 1 or 2 diabetes mellitus (T1DM or T2DM), and the treatment may not be optimized if the diagnosis is not accurate. Atypical forms include monogenic diabetes (formally known as maturity-onset diabetes of the young [MODY]), latent autoimmune diabetes of the adult (LADA), ketosis-prone diabetes, and secondary diabetes. This paper will detail the defining characteristics of each atypical form and demonstrate how they can masquerade astype 1 or 2 diabetes mellitus. Gestational diabetes mellituswill not be discussed in this article.

Patient-Specific Risk Factors and Clinical Correlates of Euglycemic Diabetic Ketoacidosis in Patients on Sodium-Glucose Co-Transporter-2 Inhibitors

Background: Sodium-Glucose Co-Transporter-2 Inhibitors (SGLT-2i) association with euglycemic diabetic ketoacidosis (EDKA) has been well reported. The underlying mechanism is mainly enhanced lipolysis and ketone bodies’ reabsorption. They also stimulate the pancreatic alpha cells and inhibit the beta cells, thereby causing an imbalance in glucagon/insulin levels, further contributing to lipolysis and ketogenesis. SGLT-2i were also found to cause EDKA in all types of diabetes, even uncovering undiagnosed Latent Autoimmune Diabetes of the Adult (LADA). Methods: Numerous electronic databases were systematically searched to identify patient-specific risk factors and clinical characteristics of EDKA in patients on SGLT-2i. The patient’s symptoms, clinical profile, laboratory results, and precipitants for EDKA were reviewed. Results: A total of 96 case reports identifying 116 patients with EDKA was fully reviewed. EDKA was twice prevalent in females (66.3%) than males (33.6%); median age was 52.15 ± 13.47, BMI was 29.3 ± 7.0. Among the 116 DKA events in SGLT-2i 92 (79.3%) were associated with Type-2 DM, 15 (12.9%) were Type-1 DM, 8 (6.9%) in LADA. Common symptoms were nausea (48.7%), vomiting (47%), and abdominal pain (28.2%). Canagliflozin was the most common SGLT-2i (40.5%), followed by Empagliflozin (29.3%) and Dapagliflozin (25.9%). The most common precipitant was surgery (17.2%), followed by infection (14.7%), fasting (11.2%), and Keto Diet (9.5%); others being reduced insulin use, alcoholism, and cancer. At presentation, average blood glucose was 196.8 ± 96.5, pH 7.1 ± 0.16, HCO3 8.7 ± 5.7 mmol/L, potassium 4.3 ± 1.03, anion-gap 24.2 ± 6.8 mmol/L, and the average HbA1C was 9.24 ± 2.08. Urine Ketones were positive in 81.89% of patients. 17 patients had pancreatic autoantibodies testing, and 7 were positive (41.2%) for glutamic acid decarboxylase-65 antibodies (anti-GAD-65). As a result, 7 patients were newly diagnosed with LADA who were previously misdiagnosed with type-2 DM. Conclusion: SGLT2i induced EDKA was found to be more predominant in females and type-2 DM. Diabetics should be educated on risk factors and consult physicians before commencing a dietary or exercise change. Physicians should be vigilant in diagnosing EDKA by thoughtful measurement of urine ketones and anti-GAD-65 testing can help diagnose underlying LADA.

Efficacy of a glucose meter connected to a mobile app on glycemic control and adherence to self-care tasks in patients with T1DM and LADA: a parallel-group, open-label, clinical treatment trial.

The main aim of the study was to evaluate the patients' glycemic control and adherence to self-care tasks. Patients with type 1 diabetes mellitus (T1DM) or latent autoimmune diabetes of the adult (LADA) using a multiple daily injection (MDI) regimen with carbohydrate counting (n = 25, Subgroup B) or fixed insulin dose (n = 25, Subgroup C) were allocated to use the application (app) for 12 weeks. Both subgroups were compared with each other and against a control group (n = 25, Group A) comprising patients with T1DM or LADA treated with continuous subcutaneous insulin infusion (CSII) in a parallel-group, open-label, clinical treatment trial. All patients had glycated hemoglobin (A1C) levels measured and were asked to fill out the Diabetes Self-Management Profile (DSMP) questionnaire at study start and end. The patients were instructed to measure capillary glucose six times daily in study weeks 4, 8, and 12. Mean A1C levels decreased 0.725% in Subgroup C in intragroup analysis (p = 0.0063), and had a mean variation of 0.834% compared with Group A (p = 0.003). Mean DSMP scores increased 5.77 points in Subgroup B in intragroup analysis (p = 0.0004) and increased by a mean of 6.815 points in relation to Group A (p = 0.002). OneTouch Reveal improved both A1C levels and DSMP scores in patients with T1DM or LADA compared with standard treatment (CSII).

O18 Novedoso inmunoensayo multiplex para la detección simultánea y discriminativa de los principales marcadores de autoinmunidad en diabetes mellitus

Introducción: los principales marcadores de autoinmunidad en diabetes mellitus tipo 1 (DM1) son los que presentan especificidad hacia: glutamato decarboxilasa (GADA), tirosina fosfatasa 2 asociada a insulinoma (IA-2A) y la isoforma 8 del trasportador de zinc (ZnT8A). Su detección es fundamental como apoyo diagnóstico de DM1 y para establecer la presencia de diabetes autoinmune latente del adulto (LADA) a fin de garantizar el tratamiento adecuado en forma oportuna. El método de referencia para su detección (ensayo de unión a radioligando, RBA) es altamente sensible y específico, pero costoso, contaminante del medio ambiente y su ejecución se limita a centros con infraestructura y personal habilitados por la entidad regulatoria. Por ello, es imprescindible el desarrollo de métodos alternativos que facilite el acceso al diagnóstico a un mayor número de pacientes.Objetivos: desarrollar un inmunoensayo basado en citometría de flujo (CF) para la determinación combinada y discriminativa de los principales marcadores de DM1: GADA, IA-2A y ZnT8A.Materiales y métodos: se ensayaron 10 sueros de pacientes pediátricos con reciente diagnóstico de DM1 y 20 sueros de individuos controles normales (SHN). Se empleó un modelo de doble paratope incubando las muestras con microesferas de poliestireno de 4, 5 y 7 mmadsorbidas con los antígenos recombinantes Trx-GAD, Trx-IA-2 y Trx-ZnT8, respectivamente, y las correspondientes proteínas biotiniladas. Luego de una incubación overnight a 4 ºC, los inmunocomplejos formados se detectaron empleando estreptavidina-ficoeritrina y se adquirió en un citómetro de flujo. Todas las muestras fueron evaluadas en paralelo por RBA.

Glycemic variability assessed by continuous glucose monitoring and the risk of diabetic retinopathy in latent autoimmune diabetes of the adult and type2 diabetes.

Aims/IntroductionThe relationship between glycemic variability (GV) and diabetic complications has gained much interest and remains under debate. Furthermore, the association of GV with diabetic complications has not been examined in latent autoimmune diabetes of the adult (LADA). Therefore, we evaluated the relationships among several metrics of GV with diabetic retinopathy (DR) in patients with LADA and type 2 diabetes mellitus.Materials and MethodsA total of 192 patients with LADA and 2,927 patients with type 2 diabetes mellitus were enrolled. After continuous glucose monitoring for 72 h, three metrics of GV including standard deviation, coefficient of variation and mean amplitude of glycemic excursions were calculated. DR was assessed by fundus photography performed with a digital non‐mydriatic camera.ResultsThe prevalence of DR was 20.3 and 26.4% in LADA and type 2 diabetes mellitus patients (P < 0.001), respectively. Generally, LADA patients had fewer cardiometabolic risk factors than type 2 diabetes mellitus patients, and all GV metrics were significantly higher in LADA than in type 2 diabetes mellitus. In the multivariate logistic regression analysis, no metrics for GV were identified as independent risk factors of DR (standard deviation: P = 0.175; coefficient of variation: P = 0.769; mean amplitude of glycemic excursions: P = 0.388) in LADA. However, the standard deviation was significantly associated with DR (OR 1.15, P = 0.017) in patients with type 2 diabetes mellitus after adjusting for confounders. The independent relationships of coefficient of variation and mean amplitude of glycemic excursions with DR (P = 0.194 and P = 0.251, respectively) did not reach statistical significance in type 2 diabetes mellitus.Conclusions GV is more strongly associated with DR in type 2 diabetes than in LADA, suggesting that different glucose‐lowering strategies should be used for these two types of diabetes.

Autoimmunity in Patients with Type 2 Diabetes in Newfoundland and Labrador

Latent Autoimmune Diabetes of the Adult (LADA) is a slowly progressive form of diabetes associated with autoantibody positivity. LADA shares characteristics with type 1 and 2 diabetes (T1D, T2D) but is often misdiagnosed as T2D. Epidemiologic data shows patients with LADA may account for 2 to 12% of all cases of diabetes. The aim of the study was to collect information on prevalence of autoimmunity in patients with T2D and describe their characteristics in Newfoundland and Labrador, Canada. A cross- sectional study design was used to collect data in 140 patients. The frequency of GAD 65 antibody, ICA, Insulin and C-peptide levels was examined by radioimmunoassay and enzyme-linked immunosorbent assays. We collected data on height, weight, Body Mass Index (BMI) and tested for Thyroid Stimulating Hormone and Glycosylated Hemoglobin levels. Data collected included age at diagnosis, family history and number of co-morbidities. Adults 18 years and above with T2D were included. Pregnant and lactating females were excluded. SPSS version 24 was used to analyze data. Results obtained showed 13 (8 males and 5 females, p 0 .181) of the 132 patients tested were GAD 65 positive thus placing prevalence of LADA in NL at 9.7%. Baseline characteristics were similar in both GAD 65 positive and negative patients. None of the patients tested were positive for ICA antibodies thereby improving our confidence that the sample did not contain any patients with T1D. Prevalence of GAD 65 was higher in the patients requiring Insulin whereas the C-peptide levels were lower. BMI was high in both GAD 65 positive and negative group with data trending towards higher BMI in the GAD 65 positive group. GAD 65 positivity was associated with older age group, higher BMI which is different from reported literature indicating that older age and obesity have a predictive value in diagnosis of T2D but not in LADA. Disclosure S.J. Iqbal: None.

Clinical Characteristics of GADA-Positive Patients with Diabetes and the Role of GAD Antibody Assay to Reclassify the Diagnosis in a Limited Resource Setting

Patients with diagnosis of T2DM may also have islet antibodies typically associated with T1DM, as Latent Autoimmune Diabetes of the Adult (LADA). More than 90% of LADA patients in have antibodies against Glutamic Acid Decarboxylase (GADA). Prevalence of LADA is between 4% and 12% of all adults with a clinical T2D phenotype. T1DM in a limited resource setting is generally diagnosed based mainly on clinical features which may lead to misclassified diagnosis. We utilised GAD antibody assay to reassess the challenging referred cases in our speciality centre by biochemical evaluation. We explore the clinical characteristics one-year post diagnosis of T1DM to reclassify the diagnosis in 20 patients (males = 15, females = 5). The complications reported at the time of diagnosis were, peripheral neuropathy (n=3), hypoglycaemia (n=2), peripheral vascular disease (n=1) and amputation of both toes (n=1). Five patients reported positive family history. Mean age (years) 33 ± 8.4, 95% CI 29 - 37, min 18, max 55. Mean levels of HbA1c (%) was 11 ± 3.1, 95% CI 9.6 - 13, min 7.4, max 17. Mean levels of GAD antibody (IU /ml) was 50 ± 84, 95% CI 11 - 90, min 3.6, max 255. Patients were categorised into subgroups by GADA status, GADA low: ≤ 200 IU ml (n=, GADA high: &amp;gt; 200 IU/ml. Three patients reported high GADA levels of which two were males and one female and two reported complications as amputation and hypoglycaemia. Following reclassification, nine patients were re-diagnosed as T2DM with the management plan shifted from primarily insulin based regimen to oral antidiabetics approach. Two patients each were re-diagnosed as Maturity Onset Diabetes of the Young (MODY) and early onset T2DM. Our study highlights the importance of GAD antibody assay for an early precise diagnosis in a limited resource setting. Disclosure P.J. Goswami: None. B.D. Saboo: None. K.K. Patel: None. B.N. Patel: None. N. Wadhwa: None.

Decreased quality of life and treatment satisfaction in patients with latent autoimmune diabetes of the adult.

ObjectivesOur main aim was to assess the quality of life (QoL) and treatment satisfaction (TS) of subjects with LADA (latent autoimmune diabetes of the adult) and compare these measures with those of patients with other diabetes types, i.e., type 1 (T1DM) and type 2 diabetes mellitus (T2DM).MethodsThis was a cross-sectional study with a total of 48 patients with LADA, 297 patients with T2DM and 124 with T1DM. The Audit of Diabetes-Dependent Quality of Life (ADDQoL-19) questionnaire and the Diabetes Treatment Satisfaction Questionnaire (DTSQ) were administered. Relevant clinical variables were also assessed. The data analysis included comparisons between groups and multivariate linear models.ResultsThe LADA patients presented lower diabetes-specific QoL (p = 0.045) and average weighted impact scores (p = 0.007) than the T2DM patients. The subgroup of LADA patients with diabetic retinopathy (DR) who were treated with insulin had a lower ADDQoL average weighted impact score than the other diabetic groups. Although the overall measure of TS was not different between the LADA and T2DM (p = 0.389) and T1DM (p = 0.091) groups, the patients with LADA showed a poorer hyperglycemic frequency perception than the T2DM patients (p < 0.001) and an improved frequency of hypoglycemic perception compared with the T1DM patients (p = 0.021).ConclusionsThe current findings suggest a poorer quality of life, especially in terms of DR and insulin treatment, among patients with LADA compared with those with T1DM and T2DM. Hyperglycemia frequency perception was also poorer in the LADA patients than in the T1DM and T2DM patients. Further research with prospective studies and a large number of patients is necessary.

The Case Files

The Case Files

Secreted Frizzled-Related Protein 4 (SFRP4) is Elevated in Patients with Diabetes Mellitus.

Recently, SFRP4 was identified as a molecular link between islet inflammation and defective insulin secretion. Gene co-expression analysis detected a molecule associated with type 2 diabetes mellitus (T2D), elevated HbA1c, and reduced insulin secretion in mice as well as in a pilot sample of humans. To our knowledge SFRP4 has never been investigated in patients with different types of diabetes. We included 179 patients: 46 with type 1 diabetes (T1D), 30 age matched healthy controls for patients with T1D (CO-T1D), 55 with T2D, 37 with latent autoimmune diabetes of the adult (LADA) and 30 healthy controls (CO) for patients with T2D and LADA. Apart from anthropometric data, lipids and renal parameters were assessed. SFRP4 levels were measured by a commercial ELISA. Patients with diabetes had significant higher SFRP4 levels than CO: T2D vs. CO: 37.1±26.7 vs. 8.8±3.0 ng/ml, p<0.001; LADA vs. CO: 15.6±6.2 vs. 8.7±3.0 ng/ml, p<0.001; T1D vs. CO-T1D: 24.6±17.9 vs. 16.9±4.5 ng/ml, p=0.011. SFRP4 levels were correlated with age, BMI, HbA1c, HDL-cholesterol, and triglycerides. A multivariate model revealed HDL-cholesterol, triglycerides and BMI as predictors for SFRP4. This is the first study demonstrating that SFRP4 is significantly increased in patients with different types of diabetes suggesting that this protein is generally involved in islet dysfunction and potentially subclinical inflammation irrespective of type of diabetes.

Latent autoimmune diabetes of the adult: current knowledge and uncertainty.

Patients with adult-onset autoimmune diabetes have less Human Leucocyte Antigen (HLA)-associated genetic risk and fewer diabetes-associated autoantibodies compared with patients with childhood-onset Type 1 diabetes. Metabolic changes at diagnosis reflect a broad clinical phenotype ranging from diabetic ketoacidosis to mild non-insulin-requiring diabetes, also known as latent autoimmune diabetes of the adult (LADA). This latter phenotype is the most prevalent form of adult-onset autoimmune diabetes and probably the most prevalent form of autoimmune diabetes in general. Although LADA is associated with the same genetic and immunological features as childhood-onset Type 1 diabetes, it also shares some genetic features with Type 2 diabetes, which raises the question of genetic heterogeneity predisposing to this form of the disease. The potential value of screening patients with adult-onset diabetes for diabetes-associated autoantibodies to identify those with LADA is emphasized by their lack of clinically distinct features, their different natural history compared with Type 2 diabetes and their potential need for a dedicated management strategy. The fact that, in some studies, patients with LADA show worse glucose control than patients with Type 2 diabetes, highlights the need for further therapeutic studies. Challenges regarding classification, epidemiology, genetics, metabolism, immunology, clinical presentation and treatment of LADA were discussed at a 2014 workshop arranged by the Danish Diabetes Academy. The presentations and discussions are summarized in this review, which sets out the current ideas and controversies surrounding this form of diabetes.What’s new? Latent autoimmune diabetes of the adult (LADA) is an autoimmune diabetes defined by adult-onset, presence of diabetes associated autoantibodies, and no insulin treatment requirement for a period after diagnosis. Immunologically, glutamic acid decarboxylase 65 autoantibodies are by far the most common autoantibody in adult-onset diabetes. LADA is the most prevalent form of adult-onset autoimmune diabetes and probably the most prevalent form of autoimmune diabetes in general. LADA shares genetic features with both type 1 and type 2 diabetes. Phenotypically, LADA patients are often misdiagnosed as having type 2 diabetes. LADA patients generally have worse HbA1c levels than type 2 diabetes patients. Clinically, LADA patients tend to have a lower mean age at diabetes onset, lower body mass index and more frequent need for insulin treatment than patients with type 2 diabetes. Management of LADA may require a dedicated strategy, yet currently there is a paucity of randomized controlled trial data.

A rare combination of type 3 autoimmune polyendocrine syndrome (APS-3) or multiple autoimmune syndrome (MAS-3).

ContextType 3 autoimmune polyendocrine syndrome (APS-3) is defined by the presence of an autoimmune thyroid disease and another autoimmune illness, excluding Addison’s disease; this is a frequent combination.Case presentationWe report the case of a 55 years old female patient with APS-3, with seven clinical or latent autoimmune manifestations. At 49 years of age she was admitted at the General Hospital for leukopenia, weight loss, tremors, anxiety and diarrhea. The personal history revealed ulcerative colitis and, during the last year, episodes of fever with migrant arthralgia and cutaneous lesions. The patient was evaluated for thyroid function and imaging, mielobiopsy, glycaemic control, gastrointestinal and rheumatologic disorders with specific biochemical tests, imaging and endoscopic procedures. We concluded that the patient was affected by APS-3, characterized by the association of Graves’ disease, autoimmune leukopenia, latent autoimmune diabetes of the adult (LADA), autoimmune gastritis, ulcerative colitis, Sjögren’s and anti-phospholipid syndromes. The patient started low doses of corticosteroid drugs for leukopenia, underwent 131I therapy for hyperthyroidism and later started substitutive thyroid therapy with l-thyroxine, insulin therapy for LADA, mesalazine for ulcerative colitis and artificial tears for Sjögren’s syndrome.ConclusionsIn this article we report a complex case of APS-3, characterized by the association of seven different autoimmune diseases, which required a complex therapeutic strategy.

Natural history and immunopathogenesis of type 1 diabetes

Type 1 diabetes (T1D) develops in the majority of cases as result of chronic progressive β-cell destruction. This inflammatory damage depends on a selective loss of immune tolerance, that leads to an extensive infiltration of both helper and cytotoxic T-lymphocytes in the pancreatic islets. The autoimmune mechanism is proven by the presence of a pool of autoantibodies (Abs) against structural and secretory β-cell proteins even before the disease onset (anti glutamic acid decarboxylase [GAD], anti-tyrosine phosphatase [IA 2], anti-insulin). This process, once started, and in presence of 2 or more Abs, leads to the disease in almost every subject. Different pathogenic components participate in the development of T1D, considered, therefore, a typical multifactorial autoimmune disease. Genetic features, immunological aspects and environmental factors have a different weight in determining the onset of type 1 diabetes depending on the age at the diagnosis. The genetic susceptibility extends from a marked effect in childhood-onset T1D to the relatively limited effect detected in LADA (Latent Autoimmune Diabetes of the Adult), as shown, for example, by the age-dependent diminishing twin concordance. It is clear, therefore, that there is a continuum in the pathological factors that lead to an age-related increased influence of immunological and environmental components despite the reduction in genetics weight. It is interesting to note that new elements are emerging in the natural history and immunopathogenesis of T1D including epidemiology, genetics, immunology and the effect of environment on clinical presentation.

Autoantibodies to GAD65 and IA-2 in canine diabetes mellitus

Diabetes mellitus in dogs shares many characteristics with the human type 1 disease and virtually all diabetic dogs require insulin therapy to control hyperglycaemia. Insulin deficiency is suspected to result from immune-mediated destruction of pancreatic beta cells in some cases. Human patients suffering from Type 1A (immune-mediated) diabetes or latent autoimmune diabetes of the adult (LADA) demonstrate circulating autoantibodies against the 65 kDa isoform of glutamic acid decarboxylase (GAD65) and/or insulinoma antigen-2 (IA-2). The aims of the current study were to develop radio-immunoassays to detect serum antibodies against recombinant canine GAD65 and IA-2 and to identify diabetic dogs showing serological evidence of autoreactivity to these pancreatic beta cell antigens. Canine GAD65 and the 3′ end of IA-2 (coding for amino acids 771–979 of the intracellular domain) were amplified by PCR from cDNA prepared from canine insulinoma tissue and cloned into the pCRII vector. The canine sequences were later confirmed by identifying GAD2 and PTPRN genes from the dog genome assembly. Recombinant 35S-methionine-radiolabelled canine GAD65 and IA-2 (771–979) proteins were used in radio-immunoprecipitation assays to screen sera from 30 newly diagnosed diabetic dogs and 30 control dogs. Four of 30 canine diabetic patients had significant GAD65 autoreactivity ( p < 0.01) compared to controls and 3 dogs were positive for autoantibodies to IA-2 (771–979). Two diabetic dogs showed dual autoantigen reactivity. These preliminary data indicate that serological reactivity to GAD65 and IA-2 is present in a proportion of diabetic dogs and suggests that, in some cases, canine diabetes is associated with an autoimmune response to these antigens.

Distinct Monocyte Gene-Expression Profiles in Autoimmune Diabetes

OBJECTIVE—There is evidence that monocytes of patients with type 1 diabetes show proinflammatory activation and disturbed migration/adhesion, but the evidence is inconsistent. Our hypothesis is that monocytes are distinctly activated/disturbed in different subforms of autoimmune diabetes.RESEARCH DESIGN AND METHODS—We studied patterns of inflammatory gene expression in monocytes of patients with type 1 diabetes (juvenile onset, n = 30; adult onset, n = 30) and latent autoimmune diabetes of the adult (LADA) (n = 30) (controls subjects, n = 49; type 2 diabetic patients, n = 30) using quantitative PCR. We tested 25 selected genes: 12 genes detected in a prestudy via whole-genome analyses plus an additional 13 genes identified as part of a monocyte inflammatory signature previously reported.RESULTS—We identified two distinct monocyte gene expression clusters in autoimmune diabetes. One cluster (comprising 12 proinflammatory cytokine/compound genes with a putative key gene PDE4B) was detected in 60% of LADA and 28% of adult-onset type 1 diabetic patients but in only 10% of juvenile-onset type 1 diabetic patients. A second cluster (comprising 10 chemotaxis, adhesion, motility, and metabolism genes) was detected in 43% of juvenile-onset type 1 diabetic and 33% of LADA patients but in only 9% of adult-onset type 1 diabetic patients.CONCLUSIONS—Subgroups of type 1 diabetic patients show an abnormal monocyte gene expression with two profiles, supporting a concept of heterogeneity in the pathogenesis of autoimmune diabetes only partly overlapping with the presently known diagnostic categories.

Diabetes auto-imune latente do adulto ou diabetes melito tipo 2 magro?

The prevalence of latent autoimmune diabetes of the adult (LADA) varies according to the population studied, criteria used and antibodies analyzed. In a series of 256 patients > 25 years, we found that 26 (10.2%) were anti-GAD antibody (GADA) positive and 16 of them (6.3%) progressed without initial insulin requirement. Although controversy exists, the following diagnostic criteria for LADA are suggested: age between 25 and 65 years; absence of ketoacidosis or symptomatic hyperglycemia at diagnosis or immediately thereafter, without insulin requirement for 6-12 months; and presence of autoantibodies (especially GADA). Autoimmunity and insulin resistance coexist in LADA and the contribution of these factors seems to be reflected in GADA titers. A subgroup, which is phenotypically and in terms of insulin requirement similar to type 2 diabetic patients, seems to be better identified based on the presence of low GADA titers, especially when these antibodies are present alone. On the other hand, subjects with high GADA titers and multiple antibodies show a phenotype close to that of classical DM 1 and are at a higher risk of premature beta-cell failure. Compared to GADA-negative diabetics, patients with LADA present a higher prevalence of other autoantibodies (anti-TPO, anti-21-hydroxylase and antibodies associated with celiac disease) and a higher frequency of genotypes and haplotypes indicating a risk for DM 1. Patients with high GADA titers may benefit from early insulinization and avoiding the use of sulfonylureas, delaying beta-cell failure. In contrast, patients with low GADA titers do not seem to have any disadvantage when managed as type 2 diabetic patients (GADA negative).

Influence of Family History of Diabetes on Incidence and Prevalence of Latent Autoimmune Diabetes of the Adult

The aim of this study was to investigate the association between family history of diabetes (FHD) and prevalence and incidence of latent autoimmune diabetes of the adult (LADA), type 1 diabetes, and type 2 diabetes. The results were based on cross-sectional data from 64,498 men and women (aged >or=20 years) who were in the Nord-Trøndelag Health Study, which included 128 cases of LADA, 1,134 cases of type 2 diabetes, and 123 cases of type 1 diabetes. In addition, prospective data on 46,210 subjects, which included 80 incident cases of LADA, observed between 1984 and 1986 and 1995 and 1997 were available. Patients with LADA had antibodies against GAD and were insulin independent at diagnosis. FHD was associated with a four times (odds ratio [OR] 3.92 [95% CI 2.76-5.58]) increased prevalence of LADA. Corresponding estimates for type 2 and type 1 diabetes were 4.2 (3.72-4.75) and 2.78 (1.89-4.10), respectively. Patients with LADA who had FHD had lower levels of C-peptide (541 vs. 715 pmol/l) and were more often treated with insulin (47 vs. 31%) than patients without FHD. Prospective data indicated that subjects with siblings who had diabetes had a 2.5 (1.39-4.51) times increased risk of developing LADA during the 11-year follow-up compared with those without. This study indicates that FHD is a strong risk factor for LADA and that the influence of family history may be mediated through a heritable reduction of insulin secretion.

HLA-DQ genotypes in classic type 1 diabetes and in latent autoimmune diabetes of the adult.

In 1993-1996, islet autoantibodies, C-peptide, and HLA-DQ genotypes were evaluated in 345 insulin-treated diabetic patients of all ages from the Skaraborg Diabetes Registry 5-6 years after their diagnosis and in 216 control subjects from the Skaraborg County, Sweden, population. The aims of this study were to clarify the importance of age at diagnosis of diabetes for HLA-DQ associations in patients with classic type 1 diabetes and whether patients considered to have latent autoimmune diabetes of the adult differed in their human leukocyte antigen (HLA) associations. An abnormally low fasting C-peptide value was used as the definition of type 1 diabetes, found in 182 of 345 (53%) patients. No major associations between age at diagnosis and HLA susceptibility or protective genotypes were detected in type 1 diabetic patients. Among the 163 patients with preserved beta-cell function, the frequency of HLA protective genotypes was clearly decreased (5% vs. 42%) in the 46 of 163 with islet antibodies compared with the 117 of 163 antibody-negative patients. The authors conclude that there were no major effects of age at diagnosis on HLA-DQ associations in classic type 1 diabetic patients, whereas lack of HLA-DQ protective genotypes was a feature of patients with slow-progressing type 1 diabetes (latent autoimmune diabetes of the adult).