Latent (slowly progressing) autoimmune diabetes in adults

About 10% of patients with the clinical presentation of type 2 diabetes suffer from an autoimmune form of diabetes associated with a rapid decline of residual β-cell mass and subsequent development of insulin dependency. In this condition, called latent autoimmune diabetes in adults (LADA), there are clinical and metabolic features intermediate between type 1 and type 2 diabetes. Recent studies provide novel information on the immune markers associated with progressive β-cell loss in LADA patients. However, LADA pathogenesis is still poorly understood; further studies are needed to establish general recommendation for preventing and treating this subtype of autoimmune diabetes.     

Latent autoimmune diabetes in adults (LADA) in Asian and European populations

Diabetes mellitus is a chronic disorder caused by relative or absolute insulin deficiency and characterized by chronic hyperglycaemia. It is expected that by year 2025, 80% of all type 2 diabetic patients will be living in developing or low‐ and middle‐income countries. Among Asians, there has been an overall increase in abdominal obesity; however, the risk of diabetes in these populations starts at much lower body mass index as compared to Caucasians. A significant proportion of diabetic patients with adult‐onset, initially nonrequiring insulin treatment, have diabetes‐associated autoantibodies in their sera. A new subclass of diabetes with the designation of latent autoimmune diabetes of adult‐onset (LADA) has been proposed for this category of subjects. Studies have demonstrated that patients with autoimmune diabetes, characterized by the presence of glutamic decarboxylase autoantibodies display a different clinical phenotype from classical type 2 diabetes without glutamic decarboxylase autoantibodies. This subset of phenotypic type 2 diabetes subjects with islet autoantibodies tend to have sulphonylurea failure and need insulin treatment earlier in the disease process. Diagnosing LADA at an initial stage will be important so that insulin can be initiated earlier, facilitating improved glycemic control sooner as well as the preservation of residual beta‐cell function in adult‐onset autoimmune diabetes. Because of differences in dietary habits, environmental factors, and phenotypic characteristics between European and Asian populations, there may be heterogeneity in the prevalence and other characteristics of LADA in these two populations.     

Latent autoimmune diabetes in adults (LADA) should be less latent

Latent autoimmune diabetes in adults (LADA) is the term coined to describe adults who have a slowly progressive form of autoimmune or type 1 diabetes that can be treated initially without insulin injections. The diagnosis of LADA is currently based on three clinical criteria: (1) adult age at onset of diabetes; (2) the presence of circulating islet autoantibodies, which distinguishes LADA from type 2 diabetes; and (3) insulin independence at diagnosis, which distinguishes LADA from classic type 1 diabetes. The prevalence of LADA in adults presenting with non-insulin-requiring diabetes is approximately 10%. Recognition of LADA expands the concept and prevalence of autoimmune diabetes, but LADA remains poorly understood at both a clinical and research level. In this perspective, we review the nomenclature, diagnostic criteria, genetics, pathology and therapy of LADA, to arrive at recommendations that might advance knowledge and management of this form of diabetes.A perspective commissioned by the Immunology of Diabetes Society and dedicated to the memory of Umberto di Mario.     

Equivalent insulin resistance in latent autoimmune diabetes in adults (LADA) and type 2 diabetic patients

Insulin resistance is a primary component in the pathophysiology of type 2 diabetes. In latent autoimmune diabetes in adults (LADA), insulin resistance has been reported to be significantly lower than in autoantibody-negative type 2 diabetes (T2DM), but whether this might be related to differences in body mass index (BMI) has not been excluded. Furthermore, previous studies have used limiting inclusive criteria for LADA, requiring only the presence of GADA or IA-2A. To apply more inclusive criteria for LADA, consistent with recent recommendations, we defined LADA by clinical manifestations characteristic of T2DM, but with the presence of any combination of GADA, IA-2A, ICA, or IAA. We recruited 43 LADA patients, 70 T2DM patients, and 150 non-diabetic controls. Insulin resistance was assessed by both the homeostasis model assessment and the quantitative insulin sensitivity check index, and BMI was calculated. We found that insulin resistance in LADA is equivalent to that of T2DM. When insulin resistance is assessed as a function of BMI, both diabetic populations demonstrated an insulin resistance equally greater than normal controls. The interaction between insulin resistance and BMI in the two diabetic groups was significantly different from that demonstrated in non-diabetic controls. In summary, LADA demonstrates insulin resistance of similar magnitude to T2DM, but with the concurrent component of an immune attack against the pancreatic beta-cells. LADA patients may be at significant risk for metabolic consequences of insulin resistance other than glucose metabolism, such as those described in the metabolic syndrome. As complications and treatment regimens specific to LADA are realized, improved means of identification of LADA will become increasingly important.     

Prevalence of latent autoimmune diabetes of adults (LADA) in Southern Spain

OBJECTIVE: To study the prevalence of diabetes mellitus and islet autoantibodies in an adult population from Southern Spain. RESEARCH AND METHODS: A cross-sectional study in Southern Spain of 1226 people, age 18-65 years. Clinical data were obtained and a blood sample taken to measure autoantibodies (glutamic acid decarboxylase antibodies (GADAb), tyrosine phosphatase antibodies (IA2Ab), and insulin antibodies (IAA)). An oral glucose tolerance test (OGTT) was also given to 982 of the subjects. RESULTS: The overall prevalence of diabetes mellitus according to the WHO 1979 criteria was 10.9% and according to the ADA 1997 criteria it was 14.7% (8.8% were unaware of their diabetes). The prevalence of impaired fasting glucose (IFG) was 12.4% and of impaired glucose tolerance (IGT) 11.5%. The prevalence of GADAb+ in the general population was 0.9% and in the diabetic population 3.7%. There were no significant differences between groups in the prevalence of IA2Ab or IAA (both were 0.8% in the general population). Of the three autoantibodies studied, only GADAb were significantly different in the diabetic population (P=0.0006). CONCLUSIONS: The prevalence of Type 2 diabetes and LADA are high in the south of Spain.     

成人隐匿性自身免疫性糖尿病患者胰岛β细胞功能的6年前瞻性研究

目的探讨谷氨酸脱羧酶抗体(GAD-Ab)阳性的成人隐匿性自身免疫性糖尿病(LADA)患者胰岛β细胞功能变化的特点及其影响因素.方法GAD-Ab阳性的LADA患者45例(LADA 1组16例,LADA2组29例),年龄28～68岁;GAD-Ab阴性的2型糖尿病(T2DM)患者45例(T2DM 1组16例,T2DM 2组29例),年龄26～68岁.每半年随访一次,LADA 1组和T2DM1组随访至第6年,LADA 2组和T2DM 2组随访至第1.5年.测定空腹C肽(FC-P)和100 g馒头餐后2 h C肽(2 hC-P)及糖代谢控制指标.采用放射配体法测定GAD-Ab,放免法测定C-P.结果LADA 1组的FC-P较入组时下降50%以上,随访第1.5年时为25%,随访第2.5年平均水平呈显著性下降[(396±189)pmol/L对(573±289)pmol/L,P＜0.05]直至第6年,而T2DM 1组的FC-P在随访期间则无显著变化(P＞0.05);LADA患者平均每年FC-P下降15.8%(4.0%～91.0%),而T2DM平均为5.2%(-3.5%～35.5%,P=0.000).LADA患者的FC-P与GAD-Ab滴度呈负相关(r=-0.483,P=0.000)FC-P平均每年下降百分数的相关因素为GAD-Ab滴度、体质指数(BMI)和发病年龄(r分别为0.408、-0.301和-0.523,P＜0.05).结论LADA患者胰岛β细胞功能减退的速率是T2DM的3倍,但其个体间异质性较大;GAD-Ab滴度是其重要预测因子,且发病年龄和BMI亦有一定预测作用.     

Latent autoimmune diabetes in adults (LADA) in South Wales: incidence and characterization

Aim To define the incidence and characteristics of latent autoimmune diabetes in adults (LADA). Methods We estimated the incidence of LADA by examining the incidence of Type 2 diabetes and calculating the proportion that were antibody positive. The incidence of Type 2 diabetes was calculated by analysis of computer records of 35 out of 36 general practices in Swansea. In addition, thirty‐two practices participated in recruiting people with Type 2 diabetes to have glutamic acid decarboxylase (GAD) antibody testing. Results The crude proportion of Type 2 patients testing positive for GAD antibodies (GADA) was 4.0% (28/683). This figure did not change when we analysed only the practices that tested more than 60% of all eligible patients. In these practices, 79% (387/487) of all eligible patients were GADA tested and 14/387 [3.6% (95% confidence interval: 2.1–6.1%)] were classified as having LADA. This gives an incidence of LADA of 9 per 100 000 (95% confidence interval: 4.4–17.8 per 100 000) people per year registered with a general practitioner. Patients testing positive for GADA were more likely to have a lower body mass index, other antibodies, to present with acute symptoms and to have higher glycated haemoglobin. Conclusions This is the first study of the incidence of LADA in primary care. People with LADA make up a significant proportion of people with apparent Type 2 diabetes. Patients with LADA are likely to be symptomatic, have poorer glycaemic control and have other autoimmune antibodies.     

Insulin intervention in slowly progressive insulin-dependent (type 1) diabetes mellitus

OBJECTIVE: We tested the hypothesis that insulin therapy rather than sulfonylurea (SU) treatment is preferable to reverse or preserve beta-cell function among patients with slowly progressive insulin-dependent (type 1) diabetes (SPIDDM) or latent autoimmune diabetes in adults. METHODS: This multicenter, randomized, nonblinded clinical study screened 4089 non-insulin-dependent diabetic patients for glutamic acid decarboxylase autoantibodies (GADAb). Sixty GADAb-positive non-insulin-requiring diabetic patients with a 5-yr duration or shorter of diabetes were assigned to either the SU group (n = 30) or the insulin group (n = 30). Serum C-peptide responses to annual oral glucose tolerance tests were followed up for a mean of 57 months. The primary endpoint was an insulin-dependent state defined by the sum of serum C-peptide values during the oral glucose tolerance test (SigmaC-peptide) less than 4 ng/ml (1.32 nmol/liter). RESULTS: The progression rate to an insulin-dependent state in the insulin group (three of 30, 10%) was lower than that in the SU group (13 of 30, 43%; P = 0.003, log-rank). Longitudinal analysis demonstrated that SigmaC-peptide values were better preserved in the insulin group than in the SU group. Multiple regression analysis demonstrated that insulin treatment, a preserved C-peptide response, and a low GADAb titer at entry were independent factors in preventing progression to an insulin-dependent state. Subgroup analysis suggested that insulin intervention was highly effective for SPIDDM patients with high GADAb titers [> or =10 U/ml (180 World Health Organization U/ml)] and preserved beta-cell function [SigmaC-peptide > or = 10 ng/ml (3.31 nmol/liter)] at entry. No severe hypoglycemic episodes occurred during the study. CONCLUSIONS: Insulin intervention to preserve beta-cell function is effective and safe for patients with SPIDDM or latent autoimmune diabetes in adults.     

成人隐匿性自身免疫性糖尿病与HLA-DQ、DR基因的关联性

探讨成人隐匿性自身免疫性糖尿病（LADA）与HLA-DQ、DR基因的关联性. 方法用聚合酶链反应序列特异性引物（PCR-SSP）检测60例正常人、41例1型糖尿病人（TlDM）和39例LADA患者的HLA-DR、DQ基因频率. 结果HLA-DR3、DR4、HLA-DQA1＊0301、HLA-DQB1＊0201与TlDM的易感性相关;HLA-DR15、HLA-DQB1＊0601与T1DM的保护性相关.HLA-DR4、HLA-DQA1＊0301、HLA-DQB1＊0201与LADA的易感性相关,HLA-DQB1＊0601的基因频率在LADA组中显著高于TlDM组（P＜0.05）. 结论不同的遗传背景可能是影响LADA和TlDM起病方式及病情进展的重要因素之一.     

Rosiglitazone combined with insulin preserves islet beta cell function in adult-onset latent autoimmune diabetes (LADA)

BACKGROUND: LADA is thought to result from the chronic autoimmune destruction of the insulin-producing pancreatic beta cells. In addition to antidiabetic effects, the newly developed insulin sensitizer-thiazolidinediones have the potential to increase the insulin content of islet cells by downregulating local inflammation and autoimmune response. Therefore, we hypothesized that LADA patients might benefit from thiazolidinediones treatment. METHODS: LADA patients, with a fasting C-peptide (FCP) of 0.3 nmol/L or more, were enrolled and randomly assigned to receive subcutaneous insulin alone (insulin group, n = 12) or rosiglitazone plus insulin (insulin + RSG group, n = 11) to compare the impacts on islet beta cell function. Plasma glucose, HbA 1c, fasting C-peptide (FCP) and C-peptide after 2 h 75-g glucose load (PCP) were determined every 6 months. GAD-Ab and C-peptide were measured with radioimmune assays. Islet beta cell function was evaluated by PCP and DeltaCP(DeltaCP = PCP-FCP). RESULTS: All of the 23 patients have been followed up for 6 months, 17 cases for 12 months and 14 for 18 months. (1) During 6 months' follow-up, there were no significant changes for DeltaCP and PCP levels in both groups. (2) PCP and DeltaCP levels in insulin + RSG group patients stayed steady during the 12 months' observation (P = 0.161 for both PCP and DeltaCP), while in the insulin alone group, both FCP (P = 0.021) and PCP (P = 0.028) levels decreased significantly. Furthermore, PCP (P = 0.004) and DeltaCP(P = 0.015) differences between 12th month and baseline were higher in insulin + RSG group than those in the insulin group. (3) When observed up to 18 months, PCP and DeltaCP levels in insulin + RSG group patients still stayed steady, while PCP and DeltaCP levels decreased more in the insulin alone group. CONCLUSIONS: This pilot study suggests that rosiglitazone combined with insulin may preserve islet beta cell function in LADA patients.     

Insulin and glucagon secretion are suppressed equally during both hyper- and euglycemia by moderate hyperinsulinemia in patients with diabetes mellitus

Hyper- and euglycemic clamp studies were performed in patients with noninsulin-dependent diabetes mellitus to examine the effects of exogenous insulin administration on insulin and glucagon secretion. Plasma glucose was kept at the fasting level [mean, 10.0 +/- 0.2 (+/- SE) mmol/L; hyperglycemic clamp], and graded doses of insulin (1, 3, and 10 mU/kg.min, each for 50 min) were infused. The plasma C-peptide level gradually decreased from 523 +/- 66 to 291 +/- 43 pmol/L (n = 13; P less than 0.005) by the end of the hyperglycemic clamp study. After 90 min of equilibration with euglycemia (5.4 +/- 0.1 mmol/L; euglycemic clamp), the same insulin infusion protocol caused a similar decrease in the plasma C-peptide level. With the same glucose clamp protocol, physiological hyperinsulinemia for 150 min (676 +/- 40 pmol/L), obtained by the infusion of 2 mU/kg.min insulin, caused suppression of the plasma C-peptide level from 536 +/- 119 to 273 +/- 65 pmol/L during hyperglycemia and from 268 +/- 41 to 151 +/- 23 pmol/L during euglycemia (n = 9; P less than 0.005 in each clamp). Plasma glucagon was suppressed to a similar degree in both glycemic states. These results demonstrate that 1) insulin secretion in non-insulin-dependent diabetes mellitus is suppressed by high physiological doses of exogenous insulin in both the hyper- and euglycemic states, the degree of inhibition being independent of the plasma glucose level; and 2) glucagon secretion is also inhibited by such doses of exogenous insulin.     

Insulin and glucagon secretion in diabetic and non-diabetic patients with circulating islet cell antibodies

Summary Thirty-nine patients (14 non-diabetics, 8 chemical diabetics, and 17 overt diabetics) with circulating islet cell antibodies (ICA) were studied. Insulin and glucagon secretion after oral (100 g) and intravenous glucose loading (200 mg/kg bolus injection followed by an infusion of 20 mg/min over 60 min) and arginine infusion (25 g over 30 minutes) were evaluated in these patients and in non diabetic and diabetic ICA-negative controls. In the non-diabetic groups with or without ICA, insulin and glucagon responses to glucose were similar. Moreover, in ICA positive patients the response of these hormones to arginine infusion was reduced. Similar alterations in insulin and glucagon secretion were observed in the ICA positive and negative patients with chemical or overt diabetes. In particular, fasting hyperglucagonaemia and glucagon hyperresponse to arginine are associated with a lack of insulin secretion in the patients with overt diabetes. Hormonal differences between diabetics with and without ICA could not be detected.This work was previously presented at the 12th Meeting of the European Association for the Study of Diabetes, Helsinki, September 1976 and published in abstract form in Diabetologia12, 422 (1976)     

Family history of type 1 and type 2 diabetes and risk of latent autoimmune diabetes in adults (LADA)

BackgroundA family history of diabetes (FHD) is a strong predictor of diabetes risk, yet has rarely been investigated in latent autoimmune diabetes in adults (LADA). This study therefore investigated the risk of LADA and type 2 diabetes (T2D) in relation to FHD, taking into account the type of diabetes in relatives.MethodsData from a population-based study were used, including incident cases of LADA [glutamic acid decarboxylase antibody (GADA)-positive, n = 378] and T2D (GADA-negative, n = 1199), and their matched controls (n = 1484). First-degree relatives with disease onset at age < 40 years and taking insulin treatment were classified as type 1 diabetes (T1D) or, if otherwise, as T2D. Odds ratios (ORs) were adjusted for age, gender, BMI, education and smoking. Cases were genotyped for high- and low-risk HLA genotypes.ResultsBoth FHD–T1D (OR: 5.8; 95% CI: 3.2–10.3) and FHD–T2D (OR: 1.9; 95% CI: 1.5–2.5) were associated with an increased risk of LADA, whereas the risk of T2D was associated with FHD–T2D (OR: 2.7; 95% CI: 2.2–3.3), but not FHD–T1D. In LADA patients, FHD–T1D vs FHD–T2D was associated with higher GADA but lower C-peptide levels, lower prevalence of low-risk HLA genotypes (5.0% vs 28.6%, respectively; P = 0.038) and a tendency for higher prevalence of high-risk genotypes (90.0% vs 69.1%, respectively; P = 0.0576).ConclusionThe risk of LADA is substantially increased with FHD–T1D but also, albeit significantly less so, with FHD–T2D. This supports the idea of LADA as a mix of both T1D and T2D, but suggests that the genes related to T1D have greater impact. LADA patients with FHD–T1D had more T1D-like features, emphasizing the heterogeneity of LADA.     

Clinical and metabolic characteristics of patients with latent autoimmune diabetes in adults (LADA): Absence of rapid beta-cell loss in patients with tight metabolic control

Aim and methodsThe present study compared the clinical and metabolic characteristics of latent autoimmune diabetes in adults (LADA) with type 2 diabetes, as well as the residual beta-cell function and progression to insulin treatment, over a 2-year follow-up period, of antibody (Ab)-positive and Ab-negative patients who achieved tight glycaemic control (HbA_1c 7.0 ± 0.8% and 6.5 ± 0.9%, respectively, at the time of entry into the study).ResultsGlutamic acid decarboxylase antibodies (GADA) and/or islet cell antibodies (ICA) were detected in 10% of patients presenting with non-insulin-dependent diabetes. Around half of Ab-positive patients required insulin treatment during the follow-up. Ab-positive patients displayed lower stimulated C-peptide levels both at entry and during the follow-up compared with Ab-negative patients, although no significant decline in C-peptide levels was observed in either subgroup over two years. Nevertheless, Ab-positive patients progressed more frequently to insulin treatment, and stimulated C-peptide tended to decrease in LADA patients who subsequently required insulin, whereas it remained stable in those who were non-insulin-dependent. In those who progressed, the trend towards C-peptide decline persisted even after starting insulin treatment.ConclusionLADA patients demonstrate lower residual beta-cell function than do type 2 diabetes patients. However, those who achieve tight metabolic control do not present with a rapid decline in beta-cell function. Further studies are needed to determine the optimal treatment strategy in such patients.