Small Nerve Fiber Damage and Langerhans Cells in Type 1 and Type 2 Diabetes and LADA Measured by Corneal Confocal Microscopy

PurposeIncreased corneal and epidermal Langerhans cells (LCs) have been reported in patients with diabetic neuropathy. The aim of this study was to quantify the density of LCs in relation to corneal nerve morphology and the presence of diabetic neuropathy and to determine if this differed in patients with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and latent autoimmune diabetes of adults (LADA).MethodsPatients with T1DM (n = 25), T2DM (n = 36), or LADA (n = 23) and control subjects (n = 23) underwent detailed assessment of peripheral neuropathy and corneal confocal microscopy. Corneal nerve fiber density (CNFD), branch density (CNBD), length (CNFL) and total, immature and mature LC densities were quantified.ResultsLower CNFD (P < 0.001), CNBD (P < 0.0001), and CNFL (P < 0.0001) and higher LC density (P = 0.03) were detected in patients with T1DM, T2DM, and LADA compared to controls. CNBD was inversely correlated with mature (r = –0.5; P = 0.008), immature (r = –0.4; P = 0.02) and total (r = –0.5; P = 0.01) LC density, and CNFL was inversely correlated with immature LC density (r = –0.4; P = 0.03) in patients with T1DM but not in patients with T2DM and LADA.ConclusionsThis study shows significant corneal nerve loss and an increase in LC density in patients with T1DM, T2DM, and LADA. Furthermore, increased LC density correlated with corneal nerve loss in patients with T1DM.     

Longitudinal changes in epitope recognition of autoantibodies against glutamate decarboxylase 65 (GAD65Ab) in prediabetic adults developing diabetes

We analysed the beta cell-specific autoimmunity reflected in autoantibodies to the smaller isoform of glutamate decarboxylase (GAD65Ab) in the prediabetic period of GAD65Ab-positive healthy adults who developed Type 2 diabetes (T2D) during a follow-up period of 10 years. We found that of the adults that tested GAD65Ab-positive at baseline (n=25), six developed T2D and one developed Type 1 diabetes (T1D). Of the subjects that tested GAD65Ab-negative at baseline (n=2209), 81 developed T2D, one developed T1D and four developed unclassified diabetes, indicating that the risk for GAD65Ab-positive healthy adults to develop diabetes is increased sixfold. The GAD65Ab epitopes were characterized in a competition radioligand binding assay using recombinant Fab derived of GAD65-specific monoclonal antibodies. We observed that the GAD65Ab epitope specificities in the prediabetic period changed dynamically. Specifically, the binding to a middle and a C-terminal epitope increased during the follow-up period (P=0 x 03), causing a significant increase in the number of epitopes recognized (P=0 x 03). These findings are similar to previous observations of dynamic changes in the prediabetic period of schoolchildren at high risk for T1D development. However, the character of the epitopes differs between the two populations, suggesting differences in the beta cell-specific autoimmune response in the prediabetic period of patients with latent autoimmune diabetes in adults (LADA) and T1D.     

羧基肽酶-H抗体阳性成人隐匿性自身免疫性糖尿病患者体内Th1、Th2亚型T淋巴细胞增殖情况观察

目的 了解人胰岛自身抗原CPH介导的T细胞亚群免疫的特点,初步揭示CPH抗体参与的自身免疫破坏的机制.方法 收集20名LADA和20名青少年Ⅰ型糖尿病患者和20名健康人的血液,利用流式细胞仪分离出Th1、Th2亚型的T淋巴细胞,通过CPH/GAD刺激,了解不同亚型T淋巴细胞的增殖情况.结论 初步证明了CPH-Ab阳性的LADA与GAD-Ab阳性LADA和青少年TIDM的病理生理机制的差别,也证实了在LADA的检测中CPH-Ab和GAD-Ab有着同等重要的地位.     

CTLA-4 promoter polymorphisms are associated with latent autoimmune diabetes in adults

The cytotoxic T lymphocyte antigen-4 (CTLA-4) molecule is an important regulator of T-cell activation and a susceptibility candidate for autoimmune diseases. To evaluate the impact of CTLA-4 promoter allelic variants of the CTLA-4 gene in latent autoimmune diabetes in adults (LADA), the MH30 (rs231806), -1147 (rs16840252), and -318 (rs5742909) single nucleotide polymorphisms (SNPs) were studied in a population of Estonian origin, including 61 LADA patients and 230 controls. The MH30 GG genotype (p = 0.0051) and the G allele (p = 0.0023) were significantly associated with LADA. The frequency distribution of alleles and genotypes of rs16840252 and rs5742909 SNPs were not significantly different between the patient and control groups. The frequency of the CTLA-4 GCC (p = 0.000073) haplotype was significantly higher in LADA patients, whereas the frequency of the CTLA-4 CCC (p = 0.0019) was significantly lower in LADA patients in comparison with the control group. The current study confirms the involvement of CTLA-4 gene promoter polymorphisms in the susceptibility of LADA and extends our previous findings of associations with other CTLA-4 polymorphisms.     

羧基肽酶-H抗体阳性成人隐匿性自身免疫糖尿病患者的TNF-α、IL-12，IL-18、IFN-γ水平观察

目的观察羧基肽酶-H抗体（CPH—Ab）阳性成人隐匿性自身免疫糖尿病（LADA）患者的肿瘤坏死因子α（TNF—α）、白介素-12（IL-12）、白介素-18（IL-18）、干扰素-γ（IFN-γ）的水平。方法时13例LADA患者、20例2型糖尿病（T2DM）患者及加例健康对照者，采用双抗夹心酶联免疫吸附法（ELISA）检测TNF—α、IL—12、IL—18、IFN-γ的含量。结果LADA组各项指标水平与T2DM组和对照组相比均有升高（均P〈0．05）；T2DM组TNF—α、IFN-γ水平较对照组升高（P〈0．05）；T2DM组IL—12、IL—18水平与对照组比较无明显差异（P〉0.05）。结论LADA患者体内活跃着细胞介导的细胞免疫反应，LADA诊断采取直接检测针对胰岛细胞自身抗原的细胞免疫反应要优于检测针对同一抗原的自身抗体水平。     

Diabetes mellitus among young adults in Sri Lanka—role of GAD antibodies in classification and treatment: The Sri Lanka Young Diabetes study

AIMS/HYPOTHESIS: Diabetes mellitus is increasing among young adult South Asians. The aim of this study was to determine the prevalence and phenotypic characteristics of diabetes subtypes based on GAD65 autoantibody (GADA) status in those with young adult-onset diabetes in Sri Lanka. METHODS: Clinical, metabolic and GADA data were available for 992 consecutively recruited individuals with diabetes aged < or =45 years (age at diagnosis 16-40 years). Participants were classified according to the following definitions: type 1 diabetes, insulin-dependent <6 months from diagnosis; latent autoimmune diabetes in adults (LADA), GADA-positive, age > or =30 years and insulin-independent > or =6 months from diagnosis; type 2 diabetes, GADA-negative and insulin-independent > or =6 months from diagnosis. RESULTS: The median (interquartile range) age at diagnosis and diabetes duration were 33.0 (29.0-36.1) and 4.0 (1.1-7.1) years, respectively; 42.1% were male. GADA positivity was seen in 5.4% of participants (n = 54) and GADA levels negatively correlated with age at diagnosis (p < 0.0001), BMI (p < 0.0001) and time to insulin requirement (p = 0.006). Type 1 diabetes, type 2 diabetes and LADA were present in 7.0%, 89.7% and 2.6%, respectively. The remaining 0.7% of the participants were GADA-positive, insulin independent > or =6 months from diagnosis and were diagnosed at age <30 years. The metabolic syndrome and homeostasis model assessment of beta cell function (HOMA %B) were lowest in GADA-positive type 1 diabetes and increased progressively in latent autoimmune diabetes, GADA-negative type 1 diabetes and type 2 diabetes. Among those requiring insulin, 69.2% had fasting C-peptide levels in the lowest quartile, whereas only 19.5% were GADA-positive (p < 0.0001). CONCLUSIONS/INTERPRETATION: The prevalence of GADA-positive autoimmune diabetes is low among individuals with young adult-onset diabetes in Sri Lanka. Young-onset diabetic phenotypes appear as a continuum from autoimmune type 1 diabetes to type 2 diabetes.     

LADA患者血清IL-12、IL-18及血淋巴细胞亚群研究

与2型糖尿病组及正常对照组相比,成人隐匿性自身免疫糖尿病(LADA)组外周血淋巴细胞亚群有明显变化,白细胞介素12(IL12)、白细胞介素18(IL18)水平亦升高。LADA存在明显细胞免疫紊乱,并与胰岛功能密切相关。     

Experience of the introduction of routine antibody testing in primary care and of running a trial for latent autoimmune diabetes in adults (LADA)

This brief report discusses the introduction of routine Glutamic Acid Decarboxylase Antibody (GADA) testing in primary care for newly diagnosed diabetes. GADA testing is well used and the majority of people found to be positive are initiated on insulin rapidly and progress to require a basal bolus regime.