Lin J

Frequency, Immunogenetics, and Clinical Characteristics of Latent Autoimmune Diabetes in China (LADA China Study): A Nationwide, Multicenter, Clinic-Based Cross-Sectional Study

Adult non–insulin requiring diabetes includes latent autoimmune diabetes of adults (LADA), distinguished from type 2 diabetes by the presence of islet autoantibodies. LADA China determined the characteristics of Chinese LADA. This nationwide, multicenter, clinic-based cross-sectional study was conducted in 46 university-affiliated hospitals in 25 Chinese cities. All 4,880 ketosis-free diabetic patients (<1 year postdiagnosis, without insulin therapy for >6 months, aged ≥30 years) had GAD antibody (GADA) and HLA-DQ genotype measured centrally with clinical data collected locally. GADA-positive subjects were classified as LADA. Of the patients, 5.9% were GADA positive with LADA. LADA showed a north-south gradient. Compared with GADA-negative type 2 diabetes, LADA patients were leaner, with lower fasting C-peptide and less metabolic syndrome. Patients with high GADA titers are phenotypically different from those with low GADA titers, while only a higher HDL distinguished the latter from those with type 2 diabetes. HLA diabetes–susceptible haplotypes were more frequent in LADA, even in those with low-titer GADA. HLA diabetes-protective haplotypes were less frequent in LADA. Our study implicates universal immunogenetic effects, with some ethnic differences, in adult-onset autoimmune diabetes. Autoantibody positivity and titer could be important for LADA risk stratification and accurate therapeutic choice in clinical practice.

Protective effects of 1-α-hydroxyvitamin D3 on residual β-cell function in patients with adult-onset latent autoimmune diabetes (LADA)

Previous in vitro and in vivo studies have demonstrated that vitamin D could prevent pancreatic β‐cell destruction and reduce the incidence of autoimmune diabetes. In children with type 1 diabetes, vitamin D treatment produces moderate protective effects on residual β‐cell function and has proven to be safe. Therefore, we hypothesized that vitamin D might have protective effects on β‐cell function in patients with latent autoimmune diabetes in adults (LADA), a form of slowly progressive autoimmune type 1 diabetes.

The Diagnostic Value of Zinc Transporter 8 Autoantibody (ZnT8A) for Type 1 Diabetes in Chinese

Zinc transporter‐8 (ZnT8) was recently identified as a novel autoantigen in human type 1 diabetes (T1D). Autoantibody to ZnT8 (ZnT8A) was detected in up to 80% of patients with new‐onset T1D and 26% of patients with T1D otherwise classified as negative on the basis of existing markers. As no data of ZnT8A in Chinese have been reported, we aim to evaluate the utility of ZnT8A for diagnosis of autoimmune T1D in Chinese relative to other autoantibody markers.

Rosiglitazone preserves islet β-cell function of adult-onset latent autoimmune diabetes in 3 years follow-up study

The newly developed insulin sensitizer-thiazolidinediones have the potential to downregulate inflammation and autoimmune response. The objective of this study was to observe the beneficial effects on beta-cell function in the LADA patients treated with rosiglitazone. 54 LADA patients were assigned to oral hypoglycemic agents group (GAD-Ab<175 U/mL and FCP>0.3 nmol/L) or early insulin administration group (GAD-Ab>or=175 U/mL or GAD-Ab<175 U/mL and FCP<or=0.3 nmol/L). Then, those patients were randomly assigned to receive sulfonylureas (SUs group) or rosiglitazone (RSG group) therapy, or to receive insulin alone (INS group) or rosiglitazone plus insulin (INS+RSG group). Plasma glucose, HbA1c, fasting C-peptide (FCP) and C-peptide after 2h 75-g glucose load (PCP) were determined every 6 months. The levels of PCP and delta CP were higher in RSG group compared with those in SUs group after the 18th month. The PCP level (after the 12th month) and delta CP level (after the 18th month) in INS+/-RSG group were higher than those in INS group. Rosiglitazone combined with insulin wherever or not preserved beta-cell function in LADA patients after 3 years.

DNA methylation impairs TLR9 induced Foxp3 expression by attenuating IRF-7 binding activity in fulminant type 1 diabetes.

Fulminant type 1 diabetes (FT1D) is an extremely aggressive disease characterized by the abrupt onset of insulin-deficient hyperglycemia. However, the precise mechanisms underlying disease etiology almost remain unclear. As mice deficient in regulatory T cells (Tregs) are prone to the development of an FT1D-like phenotype, we thus investigated whether FT1D patients manifest Treg deficiency and explored the related mechanisms. We first noted a significant reduction for Foxp3 and CTLA4 expression levels in PBMCs of FT1D patients. IRF-7 was found to selectively bind to the Foxp3 promoter, and by which it promotes Foxp3 transcription. Therefore, ectopic IRF-7 expression significantly promoted Foxp3 and CTLA4 expression in PBMCs, while knockdown of IRF-7 manifested opposite effect. Importantly, stimulation of PBMCs with CpG ODN, a ligand for TLR9, significantly induced Foxp3 expression, demonstrating that TLR9 signaling positively regulates Treg development. However, knockdown of IRF-7 expression almost completely diminished the enhancing effect of TLR9 signaling on Foxp3 expression, suggesting that IRF-7 is a downstream molecule of TLR9 signaling and is essential for TLR9 induced Treg generation. Of interestingly note, the Foxp3 promoter in FT1D patients was hypermethylated, indicating that DNA methylation could be a causative factor responsible for the reduced Foxp3 expression in FT1D patients. Indeed, our mechanistic studies revealed that DNA methylation blocked IRF-7 binding to the Foxp3 promoter. Together, our data support the notion that environmental insults in genetic predisposed subjects trigger Foxp3 promoter hypermethylation, which then prevents IRF-7 binding to the Foxp3 promoter and impairs Treg development/functionality contributing to the pathogenesis of FT1D.

Fulminant type 1 diabetes mellitus exhibits distinct clinical and autoimmunity features from classical type 1 diabetes mellitus in Chinese.

Fulminant type 1 diabetes mellitus (T1DM) is characterized by abrupt onset of hyperglycemia and rapid progression to ketoacidosis. This study aimed at examining the clinical and autoimmunity features of fulminant T1DM in Chinese.

High titre of antiglutamic acid decarboxylase autoantibody is a strong predictor of the development of thyroid autoimmunity in patients with type 1 diabetes and latent autoimmune diabetes in adults

Objectiveu2002 Type 1 diabetes mellitus (T1DM) is frequently associated with autoimmune thyroid diseases (AITD), but little is known about the risk of AITD in latent autoimmune diabetes in adults (LADA). We evaluated the genetic and immunological factors involved in the development of thyroid autoimmunity in patients with LADA and T1DM.

Modulation of monocyte hyperresponsiveness to TLR ligands by 1,25-dihydroxy-vitamin D3 from LADA and T2DM.

To investigate the differences of Toll-like receptors (TLRs) expression and response of monocyte and modulation of 1,25-dihydroxy-vitamin D3 on monocyte activity. Peripheral blood monocytes were collected from 23 healthy controls, 18 latent autoimmune diabetes in adults (LADA), and 22 type 2 diabetes mellitus (T2DM), respectively. CD14, TLR2 and TLR4 expression were analyzed. Moreover, the effect of 1,25-dihydroxy-vitamin D3 (1,25(OH)(2)D3) on monocyte response to lipoteichoic acid (LTA) and lipopolysaccharide (LPS) was evaluated in vitro by measuring phosphorylation level of NF-kappaB-p65 and associated cytokine production. Monocytes showed significantly higher surface CD14 expression from LADA compared with that from T2DM and controls, and high expression of TLR4 from LADA and T2DM than controls. After incubation with LPS or LTA, decreased surface expressions of CD14 were observed on monocytes from T2DM and controls, in contrast to the increased on monocytes from LADA. Activation of NF-kappaB and amounts of IL-1beta and TNF-alpha production by stimulation with ligands significantly increased in LADA and T2DM, which was modulated by 1,25(OH)(2)D3 to similar level, as compared to controls. The modulation of 1,25(OH)(2)D3 on monocytes makes us to consider more potency of vitamin D3 as therapy in LADA and T2DM.

Latent Autoimmune Diabetes in Adults With Low-Titer GAD Antibodies: Similar Disease Progression With Type 2 Diabetes: A Nationwide, Multicenter Prospective Study (LADA China Study 3)

OBJECTIVE This study investigated the relationship between GAD autoantibody (GADA) titers and changing of β-cell function in patients with latent autoimmune diabetes in adults (LADA). RESEARCH DESIGN AND METHODS This 3-year prospective study enrolled 95 subjects from 15 Chinese cities including 25 high-titer (GADA ≥180 units/mL) LADA patients, 42 low-titer (GADA <180 units/mL) LADA patients, and 28 type 2 diabetic patients, the latter two groups as controls of similar age, sex, and BMI. Clinical characteristics were determined annually, including glycosylated hemoglobin (HbA1c), fasting C-peptide (FCP), and 2-h postprandial C-peptide (PCP). RESULTS Despite similar initial FCP and PCP, FCP and PCP both decreased more in subjects with high GADA titer (FCP from mean 0.49 nmol/L at entry to 0.13 nmol/L at the third year; P < 0.05) than with low GADA titer (FCP from mean 0.48 to 0.38 nmol/L) and type 2 diabetes (FCP from mean 0.47 to 0.36 nmol/L); the latter two groups being similar. After 3 years, residual β-cell function (FCP >0.2 nmol/L) was detected in only 42% with an initial high GADA titer compared with 90% with a low GADA titer and 97% with type 2 diabetes (P < 0.01 for both). GADA positivity at the third year persisted more in subjects with initially high GADA (92%) than with low GADA (26%) titers (P < 0.01). CONCLUSIONS In selected LADA patients, initial GADA titers identified subjects with different degrees of persistent autoimmunity and disease progression. LADA patients with a low GADA titer had metabolic phenotypes and loss of β-cell function similar to type 2 diabetic patients.

From Type 1, through LADA, to type 2 diabetes: a continuous spectrum?

This study aims to explore whether diabetes mellitus from T1DM, through LADA, to T2DM presents a continuous spectrum in terms of HLA‐DQ genetic background. We recruited 223 patients with autoimmune T1DM, 215 with LADA, 206 with T2DM, and 228 nondiabetic controls, and then defined their HLA‐DQA1 and –DQB1 genotypes and haplotypes. T1DM patients were divided into two groups depending on age of onset of disease: juvenile‐onset (JO; before the age of 20) and adult‐onset (AO; after the age of 20). LADA patients were sorted according to the GADA titer: the LADA1 group had titers higher than 175 U/mL, whereas the LADA2 group had lower titers. The susceptible haplotypes of T1DM were DQA1*03‐DQB1*0303, DQA1*03‐DQB1*0401, and DQA1*05‐DQB1*0201. The protective haplotype was DQA1*0102‐DQB1*0602. The frequency of DQA1*03‐DQB1*0303 in JO, AO, LADA1, LADA2, T2DM, and control groups were 38.2%, 34.2%, 25.3%, 18.9%, 17.5%, and 16.5%, respectively. The frequencies of DQA1*05‐DQB1*0201 were 21.2%, 15.0%, 12.7%, 4.6%, 3.6% and 3.3%; the frequencies of DQA1*03‐DQB1*0401 were 11.3%, 9.4%, 11.3%, 5.4%, 4.4% and 3.3%; and the frequencies of DQA1*0102‐DQB1*0602 were 1.4%, 1.7%, 0.7%, 4.6%, 7.0%, and 5.3%. The linear‐by‐linear association showed that the frequency of DQA1*03‐DQB1*0303, DQA1*05‐DQB1*0201, and DQA1*03‐DQB1*0401 presented a decremental tendency in JO, AO, LADA1, LADA2, T2DM, and control groups. The preliminary data demonstrated that the susceptible haplotypes of the HLA‐DQ gene present a continuous spectrum from typical T1DM, through LADA, to T2DM, which deserves further investigation.