谷氨酸脱羧酶抗体和胰岛细胞抗体联合检测对1型糖尿病？…

对９８４例糖尿病患者的胰岛细胞抗体、谷氨酸脱羧酶抗体和血清Ｃ肽进行了检测与分析了解ＩＣＡ和ＧＡＤＡ阳性率以及阳性患者的胰岛功能情况，以明确ＩＣＡ和ＧＡＤＡ检测对１型糖尿病早期诊断的意义。方法采用免疫组化法检测ＩＣＡ，ＥＬＩＳＡ法定量检测ＧＡＤＡ，放射免疫法检测血清空腹和餐后Ｃ肽。结果ＩＣＡ和（或）ＧＡＤＡ阳性（阳性组）１６８例（１７．０％）高于ＩＣＡ阳性率（１０．５％）和ＧＡＤＡ阳性率（１２．０％     

谷氨酸脱羧酶抗体和胰岛细胞抗体联合检测对1型糖尿病早期诊断的意义

目的　对９８４ 例糖尿病患者的胰岛细胞抗体（ＩＣＡ） 、谷氨酸脱羧酶抗体（ＧＡＤＡ） 和血清Ｃ肽进行了检测与分析,了解ＩＣＡ 和ＧＡＤＡ 阳性率以及阳性患者的胰岛功能情况,以明确ＩＣＡ 和ＧＡＤＡ检测对１ 型糖尿病早期诊断的意义。方法　采用免疫组化法检测ＩＣＡ,ＥＬＩＳＡ 法定量检测ＧＡＤＡ, 放射免疫法检测血清空腹和餐后Ｃ 肽。结果　ＩＣＡ 和（或）ＧＡＤＡ 阳性（ 阳性组）１６８ 例（１７ ．０％ ） 高于ＩＣＡ 阳性率（１０．５ ％） 和ＧＡＤＡ 阳性率（１２．０ ％ ,Ｐ＜ ０ ．０５） 。成年患者ＧＡＤＡ 阳性率（１０ ．５％ ） 高于ＩＣＡ（７．７ ％ , Ｐ＜ ０ ．０５） , 青少年患者ＩＣＡ 阳性率（４６．５ ％） 高于ＧＡＤＡ（３１．０％ ,Ｐ＜０．０１）。抗体阳性患者的空腹和餐后Ｃ肽〔（３２５ ±３６８）ｐｍｏｌ／Ｌ和（７４５±７６７）ｐｍｏｌ／Ｌ〕明显低于抗体阴性患者〔（７０１ ±４３４）ｐｍｏｌ／Ｌ和（１ ６１４ ±９６７）ｐｍｏｌ／Ｌ,Ｐ＜０ ．００１〕。结论　自身抗体阳性患者的胰岛功能明显低于阴性患者,提示自身抗体阳性患者胰岛功能有明显损伤。在成年糖尿病患者中ＧＡＤＡ检测较ＩＣＡ 更为重要,而在青少年糖尿病患者中则ＩＣＡ阳性     

2型糖尿病患者血清GAD抗体的定量测定及相关因素分析

为了获得２型糖尿病患者谷氨酸脱羧酶（ＧＡＤ）抗体阳性标准及阳性率,我们对８１例２型糖尿病患者的血清ＧＡＤ抗体进行了定量测定,并对其相关因素进行了分析。现将结果报告如下。资料与方法：初诊２型糖尿病（符合１９８５年ＷＨＯ制订的诊断标准）患者８１例,男３６例,女４５例;年龄４９．０±１０．３岁;病程４．５±４．３年。采用放免法测定其空腹血清ＧＡＤ抗体;ＧＡＤ抗体放免试剂盒由法国ＣＩＳ公司提供。所有患者同时测量身高、体重,计算体重指数,并采用馒头餐进行Ｃ－肽释放试验,计算Ｃ－肽面积〔ｐｍｏｌ／（Ｌ·ｈ）…     

成人晚发1型糖尿病相关抗体检测意义

将３２５例成人晚发１型糖尿病患者分成胰岛素（ＬＮＳ）分泌缺乏及非ＩＮＳ分泌缺乏两组,用间接酶联免疫吸附（ＥＬＩＳＡ）法测定其县岛细胞坑体（ＩＣＡ）、胰岛素抗体（ＩＡＡ）及谷氨酸脱羧酶抗体（ＧＡＤ－Ａｂ）,比较其相关性。结果两组ＩＣＡ、ＧＡＤ、Ａｂ阳性率、酮症发生率及体重指数有显著性差异。证明ＩＣＡ、ＧＡＤ－Ａｂ可作为成人晚发１型糖尿病的早期筛选指标。     

谷氨酸脱羧酶可诱导非肥胖糖尿病小鼠免疫耐受

目的 了解猪脑谷氨酸脱羧酶（ＧＡＤ）是否能预防非肥胖糖尿病（ＮＯＤ）小鼠的Ⅰ型糖尿病和影响其胰腺自身ＧＡＤ６５表达。方法 将ＧＡＤ５０μｇ与不完全弗氏佐 剂（ＦＩＡ）５０μｌ混合后给３２只４周龄ＮＯＤ雌性小鼠腹腔注射，同时１９只单独注射ＦＩＡ作为对照。每周测定体重、血糖，２０周龄时处死小鼠，观察其病理、血清Ｃ肽和ＧＡＤ抗体，并用逆转录ＰＣＲ进行胰岛ＧＡＤ６５表达半定量。结果 ２０周龄时，ＧＡＤ组小     

谷氨酸脱羧酶抗体诊断成人隐匿性自身免疫性糖尿病探讨

采用放射配体法检测谷氨酸脱羧酶（ＧＡＤ６５）抗体，对１９５例≥３５岁非酮症Ⅱ型糖尿病起病半年以上者和４５例正常对照者的观察表明：本组Ⅱ型糖尿病者ＧＡＤ６５抗体阳性率为１４．８％，高于正常对照者的２．２％；发病年龄〈４０岁、有酮症史、体重指数（ＢＭＩ）〈２１ｋｇ／ｍ＾２、空腹血清Ｃ肽〈０．３ｎｍｏｌ／Ｌ和（或）胰升糖素刺激后６分钟血清Ｃ肽〈０．６ｎｍｏｌ／Ｌ者，ＧＡＤ６５抗体阳性率均高于相应对照组（     

谷氨酸脱羧酶（GAD65）自身抗体的放射配体检测法

为建立一种诊断和预测胰岛素依赖型糖尿病（ＩＤＤＭ）的免疫学定量检测指标，改良了Ｐｅ－ｔｅｒｓｅｎ的谷氨酸脱羧酶自身抗体（ＧＡＤ－Ａｂ）放射配体分析法，以试管内转录和翻译的标记６５ｋＤ谷氨酸脱羧酶作抗原，以蛋白Ａ凝胶作为抗体沉淀剂，用液闪仪测ｃｐｍ值。对１５例初发ＩＤＤＭ和４０例对照的测定结果显示：ＩＤＤＭ组ｃｐｍ值显著高于对照组（Ｐ＜０．００１）；以对照组ｘ±２ｓ作为阳性标准，则ＩＤＤＭ组阳性率为６７％（１０／１５），对照组为２．５％（１／４０）。故改良的ＧＡＤ－Ａｂ放射配体分析法对初发ＩＤＤＭ诊断的特异性为９７．５％，敏感性为６７％。且操作简便，易于推广。     

RGD肽类似物RGDPe抑制血小板活性的体外实验

目的为寻找活性高的肽类血小板聚集抑制剂，我们合成了ＲＧＤ（Ａｒｇ－Ｇｌｙ－Ａｓｐ）肽类似物－ＲＧＤＰｅ（Ａｃ－Ａｒｇ－Ｇｌｙ－Ａｓｐ－ＮＨＣＨ２ＣＨ２Ｃ６Ｈ５），以验证其体外抗血小板聚集活性。方法以人血为标本，采用比浊法测定血小板聚集和同位素标记方法测定其竞争性抑制１２５Ｉ标记的纤维蛋白原（Ｆｇｎ）与血小板糖蛋白（ＧＰ）Ⅱｂ／Ⅲａ结合的能力，并与Ｓｉｇｍａ公司合成的ＲＧＤＳ（阳性对照）和生理盐水（阴性对照）比较。结果ＲＧＤＰｅ抑制１２５Ｉ－Ｆｇｎ与活化血小板ＧＰⅡｂ／Ⅲａ结合的ＩＣ５０＝３．６４±０．５５×１０－５Ｍ（ＲＧＤＳ：６．０３±１．２４×１０－５Ｍ），抗ＡＤＰ诱导的血小板聚集ＩＣ５０＝７６．４２±５５．４２μＭ（ＲＧＤＳ：１１４．６７±４０．５５μＭ）。结论ＲＧＤＰｅ有较强的抑制血小板聚集活性，可能在体内有预防血栓形成功效。     

免疫介导的罕见类型糖尿病

根据１９９８年美国糖尿病学会（ＡＤＡ）关于糖尿病的诊断和分型的报告１型糖尿病是胰岛β细胞损毁导致胰岛素绝对缺乏。１型糖尿病又分为ⅠＡ免疫介导型和ⅠＢ特发型。其中Ｂ类为不明病因的１型糖尿病,虽有持续的胰岛素缺乏和酮症倾向但无自身免疫的证据;虽有很强的遗传特征但无ＨＬＡ相关性。Ａ类以前曾被称为胰岛素依赖型糖尿病、１型糖尿病、青年型糖尿病。自身免疫性胰岛破坏的标志物有岛细胞自身抗体（ＩＣＡｓ）,胰岛素自身抗体（ＩＡＡｓ）,谷氨酸脱羧酶抗体（ＧＡＤ６５）以及酪氨酸磷酸酶ＩＡ－２和ＩＡ－β抗体;大约８５％…     

结核性脑膜炎脑脊液中粒细胞集落刺激因子的测定

本文采用ＥＬＩＳＡ法检测２３例结核性脑膜炎及２１例非结核性脑膜炎脑脊液中的Ｇ－ＣＳＦ。结脑组（０．６５＋０．３２ＯＤ）明显高于非结脑组（０．１５±０．１１ＯＤ）（Ｐ＜０．０１）。诊断结脑的敏感性为９１．３％，特异性为９０．５％。Ｇ－ＣＳＦ在抗感染的非特异性细胞免疫中起重要作用，细菌及其产物是刺激和调节Ｇ－ＣＳＦ产生的主要物质。     

胰岛自身抗体在诊断1型糖尿病中的价值

用受试者工作特性曲线和似然比的方法评价谷氨酸脱羧酶抗体 (GAD65 Ab)和胰岛细胞抗体 (ICA)对诊断 1型糖尿病的价值。GAD65 Ab优于ICA ;GAD65 Ab、ICA平行试验提高阳性检出率 ,GAD65 Ab、ICA的区间似然比 ,能反映 1型糖尿病患病概率的增减     

Islet cell and glutamic acid decarboxylase antibodies in hyperthyroid patients: at diagnosis and following treatment

Objectives. To study the frequency of islet cell (ICA) and glutamic acid decarboxylase (GAD-Ab) antibodies in patients with hyperthyroidism of different types at diagnosis before treatment and in the euthyroid state following treatment. Setting. Department of Endocrinology, Malmö University Hospital, Malmö, Sweden. Subjects and design. Blood samples were collected at diagnosis from 129 hyperthyroid patients, and about 6 months later, from 78 of the patients (euthyroid state). Ninety-two patients had Graves' disease (69 females and 23 males, median age 49 years, range 17–85 years), and 37 patients had toxic nodular goitre/solitary toxic adenoma (34 females and three males, median age 69 years, range 24–86 years). Interventions. Most patients were treated by radioactive iodine following the first blood sample. Main outcome measures. ICA and GAD-Ab in serum. Results. At diagnosis of Graves' disease, ICA were detected in two out of 92 (2.2%) patients, two out of 85 (2.4%) without diabetes mellitus and in the euthyroid state in one patient. None of the patients with toxic nodular goitre/solitary toxic adenoma had detectable ICA. At diagnosis of Graves' disease, GAD65-Ab as well as GAD67-Ab were detected in 11 out of 85 (13%) patients without diabetes. As many as six out of 11 GAD67-Ab-positive patients were GAD65-Ab negative. In the euthyroid state, GAD65-Ab were found in six out of 51 (12%) and GAD67-Ab in eight out of 51 (16%) of the non-diabetic Graves' disease patients. The frequencies of GAD65-Ab and GAD67-Ab in toxic nodular goitre/solitary toxic adenoma, diabetes excluded, were 3 and 0%, respectively, in the hyperthyroid state. Conclusion . The frequency of ICA in patients with hyperthyroidism is not increased as compared to the background population. GAD-Ab seems to be associated with Graves' disease and not with hyperthyroidism. The presence of GAD67-Ab in GAD65-Ab negative sera from patients with Graves' disease indicates autoreactivity against a specific GAD67 epitope.     

GAD65 antibody prevalence and association with thyroid antibodies, HLA-DR in Chinese children with type 1 diabetes mellitus

Persistent humoral autoimmunity to the enzyme glutamic acid decarboxylase (GAD) has been described in a substantial proportion of patients with type 1 diabetes mellitus. Higher prevalence of GAD antibody in diabetes patients using a new radioligand-binding assay with recombinant human GAD65 antibodies (GAD65Ab) has been seen in several studies. Using this method, we have reassessed the prevalence of GAD65Ab and investigated the association of GAD65Ab with HbA1C values, C-peptide values, HLA-DR typing and thyroid autoimmune antibody in 70 Chinese children with type 1 diabetes mellitus (mean age of onset 8.21+/-3.84 years, mean duration 3.39+/-2.54 years). Our result revealed that GAD65 antibodies were present in 54.3% (38/70) of diabetes children. There was no significant difference in gender, diabetes onset and duration, HbA1c, C-peptide concentration and frequencies of HLA DR3, DR4, DR9, DR3/DR4, DR3/DR9 and DR4/DR9 genotypes between GAD65Ab+ and GAD65Ab- groups. There was no negative correlation between GAD65Ab values and duration of diabetes in those with GAD65Ab positivity (r=-0.239, P>0.05). The frequencies of antimicrosomal and anti-thyroglobulin antibodies in GAD65Ab+ (13.5,8.1%, respectively) were not different from GAD65- patients (9.4,12.5%, respectively).     

Titre and combination of ICA and autoantibodies to glutamic acid decarboxylase discriminate two clinically distinct types of latent autoimmune diabetes in adults (LADA)

Aims/hypothesis: This study aimed to define the immunological parameters which could be used to identify patients with the distinct metabolic features of adult latent autoimmune diabetes. Methods: Sera of 312 patients with short-term diabetes (duration < 5 years) over 35 years of age at diagnosis were screened for ICA, GAD- and IA2-Ab by antibody assays validated in workshops. The antibody status was correlated with age, BMI, residual beta-cell function, measured by fasting C-peptide, onset of diabetes-related complications and markers of the metabolic syndrome (hypertension and hyperlipidaemia). Results: A total of 51 antibody positive patients were identified. These patients had lower fasting C-peptide and less neuropathy and hypertension compared with matched antibody-negative patients. However, only patients with two or more antibodies had reduced residual beta-cell function compared with antibody-negative or single antibody-positive (ICA or GAD-Ab only) patients. Patients with two or more antibodies were also leaner and had diabetes-related complications or hypertension less frequently than single antibody-positive or antibody negative-patients. IA2 antibody status did not substantially contribute to the diagnosis or differentiation of LADA patients. Conclusion/interpretation: We concluded that the combination of ICA and GAD antibodies and high titre of GAD antibodies are characteristic of patients with insulin deficiency with the clinical features of Type I (insulin-dependent) diabetes mellitus (LADA-type 1). Single antibody positivity and low titre antibodies are markers for LADA-type 2 associated with the clinical and metabolic phenotype of Type II (non-insulin-dependent) diabetes patients. [Diabetologia (2001) 44: 1005–1010] Received: 15 January 2001 and in revised form: 4 May 2001     

A novel radioligand binding assay to determine diagnostic accuracy of isoform-specific glutamic acid decarboxylase antibodies in childhood IDDM

Summary Insulin-dependent diabetes mellitus (IDDM) is associated with autoreactivity against GAD but the diagnostic sensitivity (positivity in disease) and specificity (negativity in health) of isoform-specific GAD antibodies have yet to be defined in assay systems suitable for screening large number of samples. One set of IDDM patient (n=10) and control (n=50) standard sera were used to develop quantitative antibody assays with in vitro synthesized recombinant ³⁵S-methionine-labelled GAD65 and GAD67, respectively, and protein A-Sepharose to separate free from antibody-bound ligand. Binding levels were not normally distributed (p<0.0001) and therefore, the diagnostic accuracy of GAD antibodies was analysed by the ROC plots in population-based, consecutively-diagnosed, recent onset, 0–14 year-old patients (n=105), and matched, healthy control subjects (n=157). The ROC plots showed that the diagnostic sensitivity of GAD65 antibodies was 77% and the specificity 92% compared with 8% and 98%, respectively for GAD67 antibodies. In the IDDM sera, GAD65 and GAD67 antibodies were concordant in 7% (6 of 81) and GAD65 antibodies and ICA in 89% (72 of 81) without a correlation between the autoantibody levels. Autoantibodies to recombinant human islet GAD65 are specific and sensitive markers for childhood IDDM in this immunoassay with in vitro synthesized ³⁵S-methioninelabelled recombinant GAD.Abbreviations IDDM insulin-dependent diabetes mellitus - GAD glutamic acid decarboxylase - ROC receiver-operating characteristic - ICA islet cell antibodies - JDF Juvenile Diabetes Foundation     

Glutamic acid decarboxylase and ICA512/IA-2 autoantibodies as disease markers and relationship to residual beta-cell function and glycemic control in young type 1 diabetic patients

Circulating autoantibodies (Ab) to islet autoantigens, glutamic acid decarboxylase (GAD(65)), and tyrosine phosphatase ICA512/IA-2 have been proposed as predictive markers of type 1 diabetes mellitus. To ascertain residual beta-cell function and the clinical relevance for monitoring autoimmunity after clinical manifestation of disease, we studied 63 children at diagnosis of type 1 diabetes (mean SD age 7.5 +/- 4 years) and 91 adolescent patients with type 1 diabetes (age 14.7 +/- 1.6 years) with a mean duration of disease of 7 +/- 3.5) years. Forty-two normal adolescent subjects (age 14.6 +/- 1.8 years) without a family history of diabetes were the control group. Anti-GAD(65) and ICA512/IA-2 Ab were assessed by a quantitative radioimmunoprecipitation assay. The relationship between humoral autoimmunity and clinical parameters was explored. GAD(65) and ICA512/IA-2 Ab were detected in 56% and 63% of newly diagnosed children and the prevalence was not different in relationship to clinical characteristics. Levels of GAD(65) Ab positively correlated with diagnosis age (P <.05). Both Ab were associated with islet cell antibodies (ICA) (P <.05), but one fifth of patients had at least 1 of the 2 Ab and absent ICA. At onset, only age showed a significant relationship to residual C-peptide secretion. Among the cohort of patients with diabetes of short-mid duration, GAD(65) and ICA512/IA-2 Ab were present in 44% and 45% of cases (P >.05 and P <.05 v newly diagnosed children, respectively) and more patients were identified by these Ab (68%) than by ICA alone (34%) (P <.05). In this cohort, levels of ICA512/IA-2 Ab negatively correlated with levels of glycosylated hemoglobin (HbA(1c)) (P <.005) and with daily insulin requirement (P <.05). Moreover, the presence of some residual C-peptide secretion was significantly associated with the presence of ICA512/IA-2 Ab (P <.05). Our findings confirm that positivity for either GAD(65) or ICA512/IA-2 Ab is a highly sensitive marker of type 1 diabetes in the pediatric age group, identifying a group of patients with absent ICA immunofluorescence. The persistence of Ab to islet tyrosine phosphatase possibly represents a marker of better glycemic control and less insulin requirement, indicating residual beta-cell function, thus conferring clinical and prognostic relevance to these Ab, as well as potential usefulness in intervention strategies.     

IA-2-autoantibodies complement GAD65-autoantibodies in new-onset IDDM patients and help predict impending diabetes in their siblings

Summary IA-2 has been identified as an autoantigen that is recognized by immunoglobulins from insulin-dependent diabetic (IDDM) patients. Using a liquid phase radiobinding assay, we performed an IA-2-autoantibody (IA-2-Ab) assay in 474 IDDM patients and 482 non-diabetic control subjects aged 0–39 years. IA-2-Ab were detected in 58 % of the patients and 0.8 % of control subjects. Their prevalence in patients was lower than that of islet cell autoantibodies (ICA; 73 %) or glutamic acid decarboxylase (M_r 65 kDa)-autoantibodies (GAD₆₅-Ab; 82 %) but higher than that of insulin autoantibodies (IAA; 42 %). IA-2-Ab were more frequent in patients under age 20 years (70 %) than between 20 and 40 years (45 %; p < 0.001). In the whole IDDM group, 92 % of patients were positive for at least one of the three molecular assays, which is higher than the positivity for the ICA assay (73 %). Only 1 % was negative in the molecular assays and positive in the ICA assay. IA-2-Ab levels were positively correlated with ICA titres (p < 0.001) and HLA DQ A1^*0301 – DQ B1*0302 (p < 0.003) by multivariate analysis. In a group of 481 non-diabetic siblings (age 0–39 years) of IDDM patients only 7 were IA-2-Ab positive (1.5 %). All seven were under age 20 years and positive for at least two other autoantibodies and for DQ A1^*0301 – DQB1*0302. Four of these seven developed IDDM during the 6–70-month follow-up period. The positive predictive value of IA-2-Ab (57 %) was higher than that of ICA, GAD₆₅-Ab or IAA alone, or in combination (≤ 20 %) but these calculations are restricted by the relatively short observation period and the small number of cases. The only IA-2-Ab-negative case of pre-diabetes was also negative for IAA and GAD₆₅-Ab, while it was strongly positive for ICA. In conclusion, IA-2-Ab show a high diagnostic specificity for IDDM and are predictive markers of impending diabetes in siblings of patients. In combination with other molecular antibody assays they may replace ICA testing in future. Our data also indicate that other autoantibodies than IA-2-Ab, GAD₆₅-Ab and IAA contribute to ICA. [Diabetologia (1997) 40: 95–99] Received: 18 September 1996 and in revised form: 8 October 1996     

Vitamin D receptor gene polymorphisms influence susceptibility to type 1 diabetes mellitus in the Taiwanese population

OBJECTIVE: Vitamin D and its receptor have been suggested to play a role in the pathogenesis of type 1 diabetes mellitus. We have therefore studied the influence of vitamin D receptor (VDR) gene polymorphisms on susceptibility to type 1 diabetes, and rates of glutamic acid decarboxylase (GAD65) autoantibody and islet cell autoantibody (ICA512) positivity. SUBJECTS: AND MEASUREMENTS One hundred and fifty-seven type 1 diabetic patients and 248 unrelated normal controls were recruited for this study. Genomic DNA was extracted from peripheral blood leucocytes. All type 1 diabetic patients and controls were genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP), for three restriction sites in the VDR gene, BsmI, ApaI and TaqI. The chi2 test was used to compare the frequency of the VDR gene polymorphisms in patients and normal controls. The association of VDR gene polymorphisms in type 1 diabetes with the presence of GAD65 and ICA512 autoantibodies were also examined using the chi2 test. RESULTS: The allele frequency of the BsmI and ApaI polymorphisms, but not TaqI polymorphism, differed between patients and controls (BsmI P = 0.015; ApaI P = 0.018; TaqI P = 0.266). However, after correction for the three different polymorphisms tested, only the BsmI was significant (pc = 0.045). CONCLUSIONS: Vitamin D receptor gene polymorphisms were associated with type 1 diabetes in a Taiwanese population. However, functional studies are needed to establish the role of the vitamin D receptor in the pathogenesis of type 1 diabetes mellitus.     

Increased risk for endocrine autoimmunity in Italian type 2 diabetic patients with GAD65 autoantibodies

OBJECTIVE: Glutamic acid decarboxylase (GAD)65 autoantibodies (GAD65Ab) in type 2 diabetic subjects with secondary failure to sulphonylurea treatment identify the so-called latent autoimmune diabetes of the adult (LADA). The aim of our study was to estimate the risk for endocrine autoimmunity in type 2 diabetic subjects with GAD65Ab. DESIGN AND PATIENTS: We analysed serum samples from 600 adult subjects with a clinical diagnosis of type 2 diabetes mellitus for the presence and levels of GAD65Ab and antibodies directed against the islet autoantigen IA-2/ICA512 (IA-2/ICA512Ab). All the patients had been treated initially with hypoglycaemic agents and/or diet for at least 1 year. GAD65Ab+ subjects were studied for the presence of thyroid peroxidase autoantibodies (TPOAb), 21 hydroxylase autoantibodies (21OHAb) and frequency of HLA class II haplotypes. RESULTS: GAD65Ab were found in 67/600 (11%) and IA-2/ICA512Ab in 12/600 (2%) subjects (P < 0.0001). The presence of GAD65Ab, but not that of IA-2/ICA512Ab, was significantly associated with insulin therapy, low BMI (P < 0.0001) and low basal C-peptide (P < 0.01). Islet-cell antibodies (ICA) were detected in 43/67 (64%) GAD65Ab+ and in 10/12 (83%) IA-2/ICA512Ab + subjects. TPOAb occurred more frequently in GAD65Ab+ (16/67, 24%) than in GAD65Ab-subjects (9/174, 5%) (P < 0.0001). 21OHAb were detected only in GAD65Ab+ subjects (3/67, 4.5%) (P = 0.03 vs. GAD65Ab-subjects). None of the 21OHAb+ subjects had metabolic or clinical signs of adrenal dysfunction. HLA-DRB1*03-DQA1*0501-DQB1*0201 (DR3-DQ2) was significantly more frequent in GAD65Ab+ subjects than in healthy controls (OR = 5.42, corrected P < 0.0026). The presence of TPOAb was significantly associated with DR3-DQ2 (P = 0.024). CONCLUSIONS: Our study demonstrates that the presence of GAD65Ab identifies a subgroup of type 2 diabetic patients with high risk for thyroid and adrenal autoimmunity, and that both GAD65Ab and TPOAb are associated with the presence of HLA-DR3-DQ2, in these patients.