Graves' ophthalmopathy in the absence of elevated free thyroxine and triiodothyronine levels: prevalence, natural history, and thyrotropin receptor antibody levels.

The aims of this study were to (a) determine the prevalence of patients without elevated thyroid hormone levels in Graves' ophthalmopathy (GO) using current generation free thyroid hormone assays, (b) measure the prevalence of thyrotropin receptor antibodies (TRAb) in these cases, and (c) identify possible predictors of hyperthyroidism. Over a 30-month period, 1020 cases of thyroid eye disease were evaluated, of which only 19 (1.9%) met the diagnostic criteria. Ten (1%) had subclinical thyrotoxicosis, 7 (0.7%) were euthyroid, and 2 (0.2%) were hypothyroid as determined by a third-generation thyrotropin (TSH) assay. TRAb levels were measured in 16 of these 19 patients. The prevalence of TRAb varied according to the assay used. Polyethylene glycol-extracted thyroid-stimulating immunoglobulin (PEG-TSI), unfractionated thyroid-stimulating immunoglobulin (uTSI), first-generation porcine TSH-binding inhibitory immunoglobulin (pTBII), and second-generation human TSH-binding inhibitory immunoglobulin (hTBII) assays were positive in 93.8%, 50%, 18.8%, and 81.3% of patients, respectively. TRAb was detected by at least one method in all patients. Patients were followed up for 15 to 45 months. Hyperthyroidism developed in 4 patients (25%). Suppressed TSH levels and elevated TBII were predictors of hyperthyroidism. When sensitive assays are used, the prevalence of GO patients without elevated thyroid hormone levels is extremely low. The sensitivities of assays for TRAb detection differ substantially in these cases. PEG extraction improves the detection rate of TSI (p = 0.02), and hTBII assays improve the detection of TBII in these patients (p = 0.002). The high prevalence of TRAb in such cases supports a role for these antibodies in the pathogenesis of thyroid-associated eye disease.     

Sensitive thyrotropin and thyrotropin-receptor antibody determinations one month after discontinuation of antithyroid drug treatment as predictors of relapse in Graves' disease.

OBJECTIVE: After primary successful antithyroid drug treatment (ATDT), Graves' disease has a relapse rate of 30% to 50%. Previous studies have evaluated age, gender, goiter volume, smoking habits, and the presence of thyrotropin-receptor antibodies (TRAb) as predictive markers to facilitate an individualized patient management. Despite higher sensitivity and specificity of the new second generation human TSH-receptor assay, the predictive value of TRAb for relapse of hyperthyroidism is still controversial. In a recent prospective multicenter study we have previously shown that suppressed or low TSH values predict both early (persistence) and late relapse of Graves' disease. We now present a more detailed analysis of the predictive value of TSH and TRAb for recurrent hyperthyroidism. METHODS: Four weeks after withdrawal of ATDT, 96 patients were available for thyroid function tests, including a sensitive third-generation TSH assay and a second-generation recombinant TSH receptor assay. Relapse of Graves' disease was evaluated for a total follow-up of 2 years. RESULTS: Within 2 years, 47 of 96 patients (49%) developed relapse of hyperthyroidism. Nine patients relapsed within the first 4 weeks after withdrawal of ATDT and were thus considered to have persistent Graves' disease. Ten of 15 other patients with TSH levels below 0.3 mU/L without overt hyperthyroidism relapsed within 2 years. Twenty-five of 65 patients with normal TSH (0.3-3.0 mU/L) and 3 of 4 patients with TSH values above 3 mU/L also had recurrent hyperthyroidism. After ATDT cessation, TSH had a positive predictive value of 70% and a negative predictive value of 62% (specificity 85%) for relapse of Graves 'disease. Mean TRAb levels in the group of patients with relapse were significantly higher (11.1 IU/L +/- 0.17) than TRAb values in the remission group (4.5 IU/L +/- 0.6), p < 0.001. Using a cutoff value of 1.5 IU/L, TRAb had low positive and negative predictive values of 49% and 54%, respectively (specificity, 14%), but with a cutoff level of 10 IU/L, predictive values improved to 83% and 62%, respectively (specificity, 92%). Combination of TSH and TRAb determinations did not further improve prediction of relapse. Other factors such as gender, age, goiter volume, smoking habits, presence of thyroid-associated ophthalmopathy, and urinary iodine excretion did not show a significant influence on relapse rate. CONCLUSION: Low TSH values 4 weeks after ATDT withdrawal predict relapse of Graves' disease, both early (persistence) and, to a lesser extend, within 2 years of follow-up. Also, TRAb above 10 IU/L found in a small subset of patients, correlated with a higher relapse rate.     

Transition of nodular toxic goiter to autoimmune hyperthyroidism triggered by 131I therapy.

The use of 131I treatment in nodular toxic goiter is widely accepted. In this article, we describe transition of nodular toxic goiter into an autoimmune toxic goiter with development of thyrotropin receptor antibodies (TRAb) as a side effect of 131I treatment. In this retrospective study, 149 patients with nodular toxic goiter (100 with multinodular goiter, 49 with a solitary autonomously functioning toxic nodule) were studied. Of these 149 patients 100 became permanently euthryoid after 1 dose of 131I, and due to persistent hyperthyroidism, 32 patients needed 2-5 doses to became euthyroid. After becoming euthyroid, none of these 132 patients had relapse of hyperthyroidism in the follow-up period. Based on evaluation of the thyroid hormone variables, 17 of 149 patients had a distinctly different pattern in the changes in thyroid hormones. They developed an increase in FT4I 3-6 months posttreatment after an initial fall in FT4I. Twelve of these 17 patients were treated with antithyroid drugs before the initial 131I dose. On samples of frozen sera (-20 degrees C) anti-thyroid peroxidase (TPO) and TRAb were followed for 6 months after 131I treatment in these 17 patients. A similar follow-up was done in 20 patients (10 with and 10 without antithyroid drug pretreatment), randomly selected from the patients who did not relapse. In the remaining 112 patients, anti-TPO and TRAb levels were measured only before the 131I treatment. Of the 17 patients with relapse, 6 developed TRAb concomitant with recurrence of hyperthyroidism (4% of the study group). In 5 of the 17 patients TRAb values remained absent throughout the follow-up period. The remaining 6 patients had elevated TRAb values before 131I treatment. Among the 132 patients who did not relapse, an additional 7 cases with presence of TRAb were found. A total of 9% of the study group was found to have TRAb before 131I pretreatment. Anti-TPO was found in 20 of 149 patients (13%) before 131I treatment. Complications, either hypothyroidism or TRAb-associated hyperthyroidism, were seen in 8 of 20 patients (40%) with anti-TPO before 131I treatment, compared to 9 of 129 (7%) without (p<0.005). In conclusion, TRAb and a Graves' like hyperthyroidism can be triggered by 131I treatment in patients with nodular toxic goiter. The presence of anti-TPO seem to be a marker of an increased risk of development of TRAb-associated hyperthyroidism as well as hypothyroidism, but both side effects can be seen despite the absence of anti-TPO autoantibodies.     

TSH-receptor antibody measurement for differentiation of hyperthyroidism into Graves' disease and multinodular toxic goitre: a comparison of two competitive binding assays

OBJECTIVES: Graves' disease is characterized by stimulating autoantibodies to the TSH-receptor (TRAb). The aim of this study was to compare the performance of a new TRAb assay based on competitive binding to recombinant human TSH-receptors (H-TRAb) with an assay employing purified porcine TSH-receptors (P-TRAb). Furthermore, to evaluate the applicability of the H-TRAb assay to discriminate between patients with hyperthyroidism due to Graves' disease (GD) and multinodular toxic goitre (MNTG). DESIGN AND MEASUREMENTS: H-TRAb and P-TRAb were measured in patients with newly diagnosed hyperthyroidism due to GD (n = 106) and MNTG (n = 94). For comparison, TRAb was measured in patients with primary autoimmune hypothyroidism, euthyroid subjects with an enlarged thyroid gland by ultrasound, and healthy controls (n = 100 for each group). Patients were consecutively included from a population survey. RESULTS: If the cut-off values recommended by the manufacturer for TSH-receptor antibody positivity were used for evaluation, the sensitivity of the H-TRAb assay vs. the P-TRAb assay in diagnosing GD was: 95.3/67.9% (P < 0.001). Specificity was (H/P-TRAb): 99/99%. The sensitivity of P-TRAb was increased if the upper 97.5% limit of measurements in controls was used as cut-off (H-TRAb vs. P-TRAb: 95.3/80.2%, P < 0.001). Specificity (H/P-TRAb): 98/98%. The difference between assay performance may partly be due to a better technical performance of the H-TRAb assay with more reliable results in the low range of measurements. However, even in GD patients with clearly measurable TRAb, 25% had a P-TRAb < 50% of the value expected from the H-TRAb measurement. This suggests that a subgroup of patients produce TRAb with a higher affinity for the human than the porcine TSH receptor. A relatively high proportion of patients with MNTG were TRAb positive (H-TRAb/P-TRAb: 17/9%). Characteristics of H-TRAb positive and negative MNTG patients were compared. There was no difference between size of thyroid gland and number of nodules by ultrasonography. H-TRAb positive patients had significantly higher serum T4 and T3 and a greater number were TPO-Ab positive. CONCLUSIONS: H-TRAb diagnosed Graves' disease with a high sensitivity and specificity than P-TRAb. The high occurrence of TRAb in multinodular toxic goitre might in part reflect an overlap between Graves' disease and multinodular toxic goitre in some patients.     

1085例各种甲状腺疾病患者及正常人的血清促甲状腺受体抗体含量分析

目的 制备富含甲状腺刺激阻断性抗体(TSBAb)抗原决定簇的重组TrxTSHRc蛋白为抗原,建立人血清酶联免疫吸附(ELISA)技术,检测正常人血清促甲状腺素受体抗体(TRAb),计算阳性切限值并应用于临床甲状腺疾病特别是桥本甲状腺炎(HT)的检测分析.方法以重组TrxTSHRc蛋白为抗原,通过不同的抗原包被量、不同的血清稀释度优化,建立间接ELISA检测方法(TRAb-C ELISA以检测TSBAb为主).以此方法检测1 085例各种甲状腺疾病患者及部分正常人群血清TRAb.结果本法检测正常人A405值((-x)±s)为0.319±0.107,阳性切限值((-x)±2 s)为0.533,正常人组阳性率3.30%(9/272);HT患者阳性率66.01%(336/509),其中伴甲状腺功能减退者阳性率77.78%(252/324)、伴甲状腺功能亢进者52.94%(63/119)、甲状腺功能正常者31.82%(21/66);初发Graves病患者阳性率41.86%(44/105);治疗1年Graves病患者阳性率17.86%(5/28);单纯性甲状腺肿患者阳性率6.98%(3/43);亚急性甲状腺炎患者阳性率11.1%(5/45);非毒性结节性甲状腺肿患者阳性率8.70%(6/69);甲状腺腺瘤患者阳性率3.2%(1/31).结论TRAb-C ELISA以检测TSBAb为主,此法对自身免疫性甲状腺疾病,尤其是HT的诊断、疗效观察及预后有重要意义.     

Relationship between thyroid autoimmunity and Yersinia enterocolitica antibodies.

It has previously been proposed that subclinical Yersinia enterocolitica infection may play a role in autoimmune thyroid disease (AITD). In this study, we investigated the relationship between the thyroid autoantibodies and the antibodies that produced against different serotypes of Y. enterocolitica. A total of 215 subjects were included into the study (65 newly diagnosed Graves' disease [GD], 57 Hashimoto's thyroiditis [HT], 53 nontoxic diffuse goiter [NTDG], and 40 subjects for control group [CG]). Thyroid receptor antibodies (TRAb), thyroid and agglutinating antibodies against Y. enterocolitica serotype O:3, O:5, O:8, O:9 were measured in the blood samples. The highest incidence of Y. enterocolitica antibody positivity was measured in GD (53.8% for O:3, 29.2% for O:5, 44.6% for O:8, and 40% for O:9) and followed by HT. In patients with GD, TRAb levels were also higher than in patients with HT, NTDG, and CG. There was no difference between NTDG and CG in respect to the titer levels and the positivity of both TRAb and Y. enterocolitica antibodies. There was also a weak linear correlation between TRAb level and the titer of antibodies against Y. enterocolitica antigens. It can be concluded that Y. enterocolitica infection may play a role in etiology of GD in Turkey.     

Graves病患者血清0：3型耶尔森菌抗体测定及临床意义

应用ＥＬＩＳＡ法测定１４１例Ｇｒａｖｅｓ病患者血清０：３型耶尔森菌（ＹＥ）抗体。同时检测８１例正常人、３６例桥本甲状腺炎、１６例单纯性甲状腺肿、１０例甲状腺腺瘤或腺癌和４例亚急性甲状腺炎。阳性率分别为：正常对照组１６．０％，Ｇｒａｖｅｓ病组５５．３％，桥本甲状腺炎组４１．７％，单纯性甲状腺肿组２５．６％，甲状腺腺瘤和腺癌组１０．０％，４例亚急性甲状腺炎均为阴性。初步观察到ＹＥ抗体与ＴＳＨ受体抗体（ＴＲＡｂ）之间存在相关性（Ｐ＜０．０１）。ＹＥ抗体的测定对于研究耶尔森菌感染在Ｇｒａｖｅｓ病发病机制中的作用、明确病因、协助诊断和指导治疗均有重要意义。     

促甲状腺激素受体抗体（TRAb）检测在甲状腺疾病鉴别诊断中的应用

目的分析血清促甲状腺激素受体抗体（TRAb）测定在甲状腺疾病临床诊断中的应用价值。方法采用放射受体分析和放射免疫分析法,测定373例甲状腺疾病患者血清TRAb和T3、T4、TSH、FT3、FT4含量,并根据以上参数的含量为标准,把患者分为单纯性甲状腺肿组、桥本氏病组、原发性甲减组、甲状腺功能亢进（甲亢）组、药物性甲减组,以45例非甲状腺疾病血清中TRAb和T3、T4、TSH、FT3、FT4含量作为对照组。结果单纯性甲状腺肿组、桥本氏病组血清TRAb含量与正常对照组无差异（χ^2=0.462,P〉0.05）;甲亢组、原发性甲减组血清TRAb含量明显高于正常对照组（χ^2=17.035,P〈0.01）;药物性甲减组血清TRAb含量与甲亢组差异显著（χ^2=4.804,P〈0.05）,与正常组比较亦有显著性差异（χ^2=9.071,P〈0.05）;血清TRAb含量与各组间T3、T4、FT3、FT4及TSH浓度之间无显著相关性（χ^2=0.325,P〉0.05）。结论血清TRAb含量的监测对甲状腺疾病的诊断、鉴别诊断、疗效观察等具有临床应用价值。     

Thyrotropin receptor autoantibodies induce human thyroid cell growth and c-fos activation.

Graves' disease encompasses hyperthyroidism and a diffuse goiter associated with autoantibodies to the TSH receptor (TRAb). Although the cause of the goiter formation has been attributed to TRAb, the limited growth pattern of human adult thyroid cells in vitro has caused such a conclusion to be based on studies of nonhuman thyroid cell growth. We have recently characterized a predictable and precise technique for the measurement of human thyroid cell proliferation and function using fetal thyroid cells and have used this system to examine the influence of TRAb on human thyroid cell growth. Highly purified human immunoglobulin G (hIgG) preparations from normal individuals (n = 5) had no significant influence on human thyroid cell growth. However, hIgG from patients with detectable TRAb (TRAb-hIgG) (n = 13) induced a dose-related increase in extracellular cAMP (maximum effect at 0.1 mg/ml) and a 3-fold increase in human thyroid cell growth over a 4-day period (maximum effect at 1.5 mg/ml). Under basal thyroid cell culture conditions there were detectable, but low, levels of mRNA specific for the protooncogene c-fos, and this was markedly, and rapidly, induced by the addition of TRAb-hIgG but not normal hIgG. These data demonstrate induction of cellular growth by TRAb-hIgG in an homologous human thyroid cell culture system. Such observations support the hypothesis that goiter formation in patients with Graves' disease is, at least in part, secondary to the growth stimulating activity of TRAb-hIgG.     

Performance of a third‐generation TSH‐receptor antibody in a UK clinic

Background UK national guidelines recommend the measurement of TSH receptor antibodies (TRAb) in certain clinical scenarios. A commercial third‐generation TRAb autoantibody M22‐biotin ELISA assay was introduced in May 2008 in our centre. Objective To evaluate the diagnostic performance of a TRAb assay in a retrospective and subsequently a prospective cohort in a UK centre. Design A retrospective review of patients with thyroid disease followed by a prospective observational study in consecutive patients with newly found suppressed serum thyrotrophin (TSH). Patients and Measurements Medical records of 200 consecutive patients with thyroid disorders who had TRAb measured since the introduction of the assay. In a prospective study 44 patients with newly identified hyperthyroidism (TSH < 0·02 mIU/l) had sera assayed for TRAb prior to their clinic appointment at which a final diagnosis was sought. Results In the retrospective cohort, the manufacturer’s cut‐off point of TRAb ≥0·4 U/l resulted in a positive predictive value (PPV) of 95%, sensitivity 85%, specificity 94% and negative predictive value (NVP) 79% to diagnose Graves’ disease using defined criteria. Receiver operating characteristic (ROC) analysis determined an optimal cut‐off point of TRAb ≥3·5 U/l with a 100% specificity to exclude patients without Graves’ disease at the cost though of a lower sensitivity (43%). In the prospective study, the sensitivity, PPV, specificity and NPV were all 96% using the ≥0·4 U/l cut‐off. When combining hyperthyroid patients from both cohorts the assay sensitivity and specificity at ≥0·4 U/l cut‐off were 95% and 92% respectively. A positive TRAb result increased the probability of Graves’ disease for a particular patient by 25–35% and only six (2·5%) patients had a diagnosis of hyperthyroidism of uncertain aetiology after TRAb testing. Conclusions The assay studied specifically identifies patients with Graves’ disease. It is a reliable tool in the initial clinical assessment to determine the aetiology of hyperthyroidism and has the potential for cost‐savings.     

TSH-receptor antibodies determined by the first, second and third generation assays and thyroid-stimulating antibody in pregnant patients with Graves' disease

The measurement of TSH receptor antibody (TRAb) has been recommended to predict the risk of neonatal hyperthyroidism (NH) in pregnant women with Graves' disease (GD). For the first generation TRAb (TRAb1) assay with commercial kit (Brahms, Berlin, Germany; or Cosmic co., Tokyo, Japan) an arbitrary limit of 40 U/l or 50% was suggested to indicate risk when measured late in pregnancy. In order to substitute TRAb1 with the second generation TRAb using porcine TSH receptor (pTRAb2) and human recombinant TSH receptor (hTRAb2) and the third generation TRAb (TRAb3) assay for this purpose, we measured TRAb in these four methods late in pregnancy in a total of 62 pregnant women with Graves' disease. The data showed that no cases with TRAb1 >50% has been missed if the TRAb1 assay was replaced by the pTRAb2, hTRAb2 or TRAb3 assay using their equivalent cut-off value of 70%, 10 IU/l, and 75%, respectively, but that an additional group of women would have been included in the risk group, especially in the TRAb3 assay. Next, the effect of maternal TRAb on thyroid function of offspring was studied in the 47 pregnant women with GD (43 with TRAb1 <50% and 4 with TRAb1 >50% during late pregnancy). In 2 women who gave birth to hyperthyroid children at days 6 and 14 of life, the maternal sera had strongly positive levels of TRAb1 (73.5% and 84.1%), pTRAb2 (84.9% and 91.5%), hTRAb2 (40.68 IU/L and 89.70 IU/L) and TRAb3 (92.1% and 93.5%) late in pregnancy, with one case displaying high positive (1114.3%) thyroid stimulating antibody (TSAb) level and the other case had moderate positive (433%) TSAb level. Of the remaining 45 women, 43 had TRAb1 <50% and the other 2 had TRAb >50% including 1 with low TSAb positive and 1 with positive thyroid stimulating blocking antibody (TSBAb) and negative TSAb; all of them gave birth to euthyroid children. Finally, a serial study regarding TRAb in 23 women with Graves' disease during pregnancy showed that TRAb1, pTRAb2, hTRAb2, TRAb3 value and TSAb level decreased significantly as pregnancy progressed. In conclusion, the present study supported TRAb as a useful marker to predict the risk of NH.     

Iodine status, thyroid function, thyroid volume and thyroid autoimmunity in patients with type 1 diabetes mellitus in an iodine-replete area

OBJECTIVE: To analyze the prevalence and clinical significance of thyroid autoimmunity, thyroid volume and iodine status in patients with type 1 diabetes mellitus compared with age and sex matched healthy controls, in an iodine-deficiency improved area. METHOD: Fifty-eight patients with type 1 DM, 30 female and 28 male, who attended the pediatric endocrinology clinic of Karadeniz Technical University Hospital were included into the study. They were compared with 58 healthy children matched for sex and age. Routine thyroid function parameters, thyroid autoantibodies (TPOAb, TGAb and TRAb) and urinary iodine excretion were measured and thyroid volume was determined by ultrasonography (US). RESULTS: Twenty-six patients (44.8%) in diabetic patients and 20 subjects (34.5%) in the control group had thyroid autoantibody positivity. TPOAb and TGAb positivity were significantly high in diabetic patients (P=0.01 and P=0.032, respectively). Thyroid US revealed a thyroid volume of 6.6+/-3.5 ml (median 6.4 ml, range 1.117.2 ml) in the diabetic patients compared with 3.7+/-2 ml (median 3.1 ml, range 0.8-8.6 ml) in the control group (P=0.0001). Median urinary iodine levels of both groups were clearly above the threshold level for iodine deficiency, but 26 patients with type 1 DM (44.8%) and 16 controls (27.5%) had urinary iodine excretion below 100 microg/L, and 21 (36.2%) of diabetic patients and two subjects (3.4%) of the control group were consistent with severe iodine deficiency. No significant differences were noted in diabetic patients in terms of age, duration and metabolic control of the disease and thyroid volume when compared according to the autoantibody presence. Additionally, there were no significant differences between the iodine deficient and iodine sufficient diabetic patients in terms of age, sex, duration of disease, HbA1c, thyroid hormones and thyroid volumes. Thyroid autoimmunity was lower in patients with iodine deficiency (38.4% vs. 50%), but not statistically significant. CONCLUSION: We found that type 1 DM patients had larger thyroid volume compared with healthy control groups, and a large portion of them had the markers of autoimmune thyroid disease and iodine deficiency. Surprisingly, we found that a large portion of the healthy children had TRAb positivity. We proposed that TRAb must be considered in community surveys or prevalence studies of autoimmune thyroid disorders in iodine-replete areas. Additionally, prospective longitudinal studies are needed to determine the clinical significance of TRAb positivity in diabetic patients.     

Serum thyrotropin receptor antibodies concentrations in patients with Graves' disease before, at the end of methimazole treatment, and after drug withdrawal: evidence that the activity of thyrotropin receptor antibody and/or thyroid response modify during the observation period.

AIM AND METHODS: We performed a quantitative retrospective analysis of serum thyrotropin receptor antibody (TRAb) concentrations measured by a second-generation radioreceptor assay in 58 patients with Graves' disease (GD) at the onset of the disease, at the end of 18 month methimazole (MMI) treatment, and after MMI withdrawal in order to evaluate the correlation between the presence of these antibodies and the relapse of hyperthyroidism. Sixty healthy subjects were enrolled as a control group. RESULTS: Before MMI treatment the best cutoff TRAb value for identifying patients with GD was 1.45 UI/L (specificity, 100%; sensitivity, 98.3%). At the end of MMI treatment, serum TRAb concentrations were significantly lower (p < 0.001) than those measured at baseline, but they were still significantly higher (p < 0.001) than those found in the control subjects. At the end of MMI treatment, 44 patients (75.9%) had positive TRAb values (>1.45 UI/L). After MMI withdrawal (median, 15 months), 34 patients (58.6%) became hyperthyroid, 4 patients (6.9%) became hypothyroid, and 20 patients (34.5%) remained euthyroid. There was a significant correlation between serum TRAb concentrations at the end of MMI treatment and the percentage of patients who became hyperthyroid (r: 0.56; p < 0.001) and the time of appearance of hyperthyroidism (r: -0.38; p = 0.03). All 4 patients with TRAb values below 0.9 UI/L at the end of MMI treatment remained euthyroid throughout the follow-up period. Among the 27 patients who had serum TRAb values higher than 4.4 UI/L, 23 developed hyperthyroidism and 4 hypothyroidism. The TRAb values between 0.9 and 4.4 UI/L did not discriminate between the 27 patients (46.6%) who remained euthyroid from those who had relapse of hyperthyroidism. Thus a different TRAb end of treatment cutoff was calculated to identify patients who became again hyperthyroid. This TRAb cutoff value was 3.85 UI/L (sensitivity, 85.3%; specificity, 96.5%). All but 1 patient who had serum TRAb values above 3.85 UI/L became hyperthyroid after MMI was withdrawn (positive predictive value, 96.7%). In these patients, relapse of hyperthyroidism was independent of the changes in serum TRAb concentrations (r: 0.27; p = 0.15) and occurred after a median period of 8 weeks (range, 4-48). Hyperthyroidism also developed in 5 of 24 patients who had serum TRAb concentrations lower than 3.85 UI/L at the end of MMI treatment. In these 5 patients the relapse of hyperthyroidism occurred after a median period of 56 weeks (range, 24-120) and was always accompanied by an increase in serum TRAb concentrations. CONCLUSIONS: TRAb persist in the blood of most patients with GD after 18 months of MMI treatment. Both the frequency and the time of appearance of hyperthyroidism are closely correlated with serum TRAb concentrations at the end of MMI treatment. Our data would suggest that TRAb maintain stimulating activity after a full course of MMI treatment in the large majority of patients with GD. However, it is likely that the potency of these antibodies and/or the thyroid response to them change during treatment, as suggested by the different values measured in euthyroid control subjects and in euthyroid patients after MMI treatment.     

The role of circulating immune complexes in the pathogenesis of Graves' disease

It has recently been reported that many immunological abnormalities including the presence of TSH-receptor antibody (TRAb) were found in Graves' disease (GD). Circulating immune complexes (CIC) have also been detected in the serum of patients with GD as observed in systemic lupus erythematosus, which is thought to be a typical model of immune complex disease. The role of CIC in pathogenesis of hyperthyroidism, however, remains to be elucidated. Therefore, to clarify pathophysiological functions of CIC in GD, the levels of it in those patients were compared with their symptoms, those of TRAb, and lymphoblastogenesis (LBG) induced by phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM). The subjects were forty patients with GD without any medication, one hundred and nine patients with GD on medication with methimazole (MMI), and fifteen healthy volunteers. CIC was measured by three different methods; polyethyleneglycol precipitation method (PEG), Clq binding assay (Clq), and Protein A binding assay (PA). The normal range was estimated with the mean plus or minus two times the standard deviation of normal controls. In untreated GD, CIC determined by PEG, Clq and PA widely distributed from normal range to high levels. The positive rates of CIC determined by PEG, Clq, PA, and any one method of these three were 17.5%, 22.5%, 30.0% and 52.5%, respectively. LBG using incorporation of tritiated thymidine showed the decreases in PHA and Con A, and the increases in PWM in patients with GD. The positive rates of CIC determined by PEG and PA were significantly higher in patients without goiter or with small one than those with large one (p less than 0.05). CIC measured by all three of PEG, Clq and PA showed negative correlation with TRAb significantly (p less than 0.05, p less than 0.01, p less than 0.01, respectively). On the other hand, CIC measured by Clq showed significant negative correlation with serum thyroxine concentration (p less than 0.01). The levels of CIC, TRAb and PWM-induced LBG decreased following the tapering dose of MMI sufficient to keep patients in euthyroid state. In consequence, there were no longer any correlations between CIC and TRAb after thyroid function was normalized. These observations suggest that CIC's which have huge molecular weight or have ability to bind Fc receptor on K cell, macrophage, neutrophil, and other immune cells may be one of the factors to inhibit the goitrogenic action of TRAb, and that CIC's which have ability to activate the complement system may be one of the factors to inhibit the stimulation of secretion of thyroid hormone by TRAb.(ABSTRACT TRUNCATED AT 400 WORDS)     

Clinical value of the first automated TSH receptor autoantibody assay for the diagnosis of Graves' disease (GD): an international multicentre trial

Background  Most recently, a new rapid and fully automated electrochemiluminescence immunoassay for the determination of TSH receptor autoantibodies (TRAb) based on the ability of TRAb to inhibit the binding of a human thyroid-stimulating monoclonal antibody (M22) has been established.
Objective  To evaluate this assay system in clinical routine based on an international multicentre trial and to compare the results with other established TRAb assays.
Patients and measurements  Totally 508 Graves' disease (GD), 142 autoimmune thyroiditis, 107 subacute thyroiditis, 109 nonautoimmune nodular goitre, 23 thyroid cancer patients and 446 normal controls were retrospectively evaluated.
Results  ROC plot analysis revealed an area under curve of 0·99 (95% CI: 0·99–1·0) indicating a high assay sensitivity and specificity. The highest sensitivity (99%) and specificity (99%) was seen at a cut-off level of 1·75 IU/l. Here, the calculated positive predictive value was 95%, whereas the negative predictive value was 100%. Applying the ROC plot-derived cut-off of 1·75 IU/l we found a sensitivity for TRAb positivity within the group of newly diagnosed GD patients of 97% which is in accordance to the sum of different nonautomated porcine TSH receptor-based assays with a sensitivity of 94% indicating an excellent analytical performance of the new assay format. Detailed comparison of the automated and the sum of manual assays revealed a near identical specificity.
Conclusion  Our results demonstrate that this new assay system has a high sensitivity for detecting GD and specificity for discriminating from other thyroid diseases. This assay may represent the future technology for rapid fully automated TRAb detection.     

Measurement of thyroid blood flow area is useful for diagnosing the cause of thyrotoxicosis.

We have utilized color Doppler ultrasonography (CDU) to evaluate the thyroid blood flow area (TBFA) quantitatively, and we propose criteria to differentiate Graves' disease (GD) and destruction-induced thyrotoxicosis (DT) in patients with thyrotoxicosis. We studied 32 patients with diffuse toxic goiter, 21 with GD in the euthyroid state, 12 with chronic thyroiditis in the euthyroid state, and 31 normal individuals. TBFA was calculated as (thyroid blood flow area/thyroid area) x 100%. CDU showed high sensitivity (84%) and specificity (90%) in distinguishing GD from DT when TBFA was between 7.7% and 8.8%. Using CDU to diagnose GD in cases with TBFA >or=8% or positive serum anti-thyrotropin receptor antibody (TRAb), the sensitivity was 95% and the specificity was 90%, which are similar results to those obtained when GD was diagnosed by radioactive iodine uptake (sensitivity 100%, specificity 90%). Therefore, CDU is a more useful and economical method of distinguishing GD patients with TBFA of 8% or above from DT than measurement of TRAb or radioactive iodine uptake.     

Detection of chronic hepatitis C virus infection by four diagnostic systems: first-generation and second-generation enzyme-linked immunosorbent assay, second-generation recombinant immunoblot assay and nested polymerase chain reaction analysis.

Serum samples from 100 patients with non-A, non-B hepatitis-related chronic liver disease and 100 patients with hepatitis B-related chronic liver disease were tested by first-generation and second-generation enzyme-linked immunosorbent assays, a second-generation recombinant immunoblot assay and the nested polymerase chain reaction. In non-A, non-B hepatitis-related chronic liver disease, second-generation enzyme-linked immunosorbent assay (anti-c22 and/or c200) and second-generation recombinant immunoblot assay showed 98% positivity, whereas first-generation enzyme-linked immunosorbent assay (anti-c100-3) showed 89% positivity. The two second-generation recombinant immunoblot assay-negative samples were positive by nested polymerase chain reaction, but one second-generation recombinant immunoblot assay-positive sample was polymerase chain reaction negative. However, when this second-generation recombinant immunoblot assay-positive sample was tested by polymerase chain reaction using another set of primers, it was polymerase chain reaction positive. Therefore, 100% of the non-A, non-B hepatitis-related chronic liver disease serum samples were hepatitis C virus RNA positive by polymerase chain reaction. Nine hepatitis B-related chronic liver disease samples were first-generation enzyme-linked immunosorbent assay positive. Of the eight second-generation enzyme-linked immunosorbent assay-positive hepatitis B-related chronic liver disease samples, six were first-generation enzyme-linked immunosorbent assay positive and five were second-generation recombinant immunoblot assay positive and polymerase chain reaction positive. One indeterminate second-generation recombinant immunoblot assay sample was polymerase chain reaction negative. Therefore, second-generation recombinant immunoblot assay appears to be as useful as polymerase chain reaction for detecting a chronic hepatitis C virus infection, although some discrepancies were noted.(ABSTRACT TRUNCATED AT 250 WORDS)     

自由基在地方性甲状腺肿发病学上的可能作用

对缺碘地区的正常人，甲状腺生理肿大及Ⅱ度甲状腺肿三组人群进行了细胞抗氧化能力和免疫功能的测定。结果表明，缺碘可以导致ＬＰＯ含量增高；ＳＯＤ活性下降；ＩｇＡ和ＩｇＭ含量增高，ＴＲＡｂ阳性检出率升高。因缺碘而致的细胞抗氧化能力下降及自由基的损伤作用可能诱发甲状腺自家免疫的发生，自由基损伤作用导致的自家免疫的病理过程可能是地甲肿发病学中的一个重要继发环节。     

The different types of hyperthyroidism in Europe. Results of a prospective survey of 924 patients

In a prospective multicentric study, 924 untreated hyperthyroid patients were investigated, coming consecutively within one year into 17 thyroid centers of 6 European countries. With the aid of clinical information, evaluation of thyroid scan and centrally assayed thyroid hormones, thyroid antibodies, TSH-binding inhibiting immunoglobulins (TBII), and urinary iodine, different types of hyperthyroidism could be shown. Two types of hyperthyroidism could be defined directly: autonomous adenoma in cases of hot nodules in thyroid scan and Graves' disease, defined as hyperthyroidism with eye symptoms, and/or measurable TBII levels. The remainder, called "non-classifiable", included TBII negative Graves' patients, comprising of Hashitoxicosis, toxic nodular goiter, and other multifocal autonomies. 9.2% of the patients had an autonomous adenoma, 59.6% Graves' disease, and 31.2% unclassified hyperthyroidism. The main and significant difference between these types were mean age, goiter size, nodularity, and severity of the disease, being especially expressed in Graves' disease. Graves' patients had significantly increased T3/T4 ratios. Using as additional criteria diffuse regular uptake and/or increased T3/T4 ratios for immunogenic types of hyperthyroidism at least half of the 31.2% unclassified hyperthyroidism are probably Graves' disease. Forming two groups of iodine-deficient areas (IDA) and iodine-sufficient areas (ISA) according to the urinary iodine, it was possible to elucidate some characteristics independently of local factors. Autonomous adenoma was more frequent in IDA (10.1%) than in ISA (3.2%). Differences in iodine supply are reflected in the three types of hyperthyroidism by a significant higher prevalence of goiter, thyroid nodularity, lower thyroid hormone concentrations, and a higher rate of T3 toxicosis in IDA.(ABSTRACT TRUNCATED AT 250 WORDS)     

The prevalence of elevated serum C-reactive protein levels in inflammatory and noninflammatory thyroid disease.

C-reactive protein (CRP) levels have not been routinely used to diagnose thyroid disease, although many thyroid conditions involve inflammation. This study was intended to determine whether CRP levels could differentiate between inflammatory and noninflammatory thyroid conditions, especially between type II inflammatory amiodarone-induced thyrotoxicosis (AIT) and type I iodine-induced AIT. Serum high-sensitivity CRP levels were measured in 100 euthyroid controls (7 taking amiodarone) and 353 patients with one of the following thyroid conditions: AIT, subacute thyroiditis, toxic diffuse goiter, nodular goiter, Hashimoto's thyroiditis, shortterm hypothyroidism, or postpartum thyroiditis. No patients with nontoxic multinodular goiter (n = 34), toxic nodular goiter (n = 23), or toxic diffuse goiter, either untreated (n = 49) or euthyroid while taking methimazole (n = 33), had positive CRP levels (>10 mg/L). The occurrence of positive CRP levels among patients with Hashimoto's thyroiditis (n = 35), short-term hypothyroidism (n = 38), and postpartum thyroiditis (n = 70) did not differ significantly from controls. The occurrence of positive CRP values did not differ significantly between patients with type I and type II AIT and controls. Six of 7 patients (86%) with untreated subacute thyroiditis had positive CRP levels (p < 0.00001). These results indicate that there is only a limited role for measurement of CRP levels in the diagnosis of thyroid diseases other than subacute thyroiditis.