Association of thyrotrophin receptor antibodies with the clinical features of Graves' ophthalmopathy

OBJECTIVE: Graves' ophthalmopathy (GO) and Graves' hyperthyroidism are closely associated diseases and thought to be caused by the same autoimmune process. An obvious explanation for this would be the presence of autoantibodies reacting with an autoantigen present in the orbit and the thyroid gland. The TSH-Receptor (TSH-R) antibodies are a likely candidate, because they cause Graves' hyperthyroidism and the TSH-R appears to be present also in orbital tissues. If TSH-R antibodies are responsible for the ophthalmopathy one would expect their titres to correlate with clinical characteristics of the eye disease. The aim of the present study is to see whether TSH-R antibodies are related to the activity and severity of the thyroid-associated ophthalmopathy. DESIGN AND PATIENTS: TSH-R antibody levels were measured as TBII (TRAK assay), and TSI (cAMP response of a TSH-R transfected cell line) in serum of 63 patients with untreated moderately severe GO, accompanying Graves' thyroid disease; all patients had been euthyroid for > 2 months. RESULTS: TBII and TSI titres were strongly related to each other. TBII or TSI titres did not correlate with thyroidal or orbital disease duration, nor with TPO antibody levels. In contrast, we found a striking and highly significant correlation between the Clinical Activity Score (CAS) of the eye disease, and both TBII (r = 0.54; P < 0.0001) and TSI (r = 0.50; P < 0.0001). In addition, a weaker but significant relation was found between proptosis (in mm) and TBII (r = 0.36; P = 0.004) and TSI (r = 0.49; P = 0.0001). No correlation was found with eye muscle motility. CONCLUSION: TSH-R antibody levels correlate directly with clinical features of Graves' ophthalmopathy. The results support the hypothesis of a pathogenetic role of TSH-R antibodies and the TSH-R in the orbit of Graves' ophthalmopathy patients.     

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.     

The possible contribution of anti-Gal to Graves' disease.

Anti-Gal is a natural antibody specific for the alpha-galactosyl epitope. Previous studies suggested that Graves' disease (GD) patients had elevated anti-Gal titers compared to normal controls, but titers returned to normal after treatment. We developed an anti-Gal enzyme-linked immunosorbent assay (ELISA) using the property of anti-Gal to bind tightly to mouse laminin. We found no significant correlations between anti-Gal and thyroidstimulating immunoglobulin (TSI) or free thyroxine (T(4)) in untreated hyperthyroid GD patients (n = 15) without clinical ophthalmopathy or euthyroid, previously treated GD patients with ophthalmopathy. There was a significant regression between TSI and free T(4) in the hyperthyroid patients (p < 0.01). Addition of total anti- Gal antibody to the regression showed a trend toward improved correlation (p = 0.15 for improved correlation relative to TSI and free T(4) alone), suggesting it may stimulate GD thyroid tissue. However, in contrast to previous studies we found hyperthyroid patients (n = 20) had lower levels of anti-Gal immunoglobulin G (IgG) (18.4 +/- 4.0 vs. 41.8 +/- 8.9) than normals (n = 36 p < 0.05). Interestingly, hyperthyroid patients without clinical ophthalmopathy tended to have lower IgG anti-Gal levels than euthyroid patients with ophthalmopathy (p = 0.1). Hyperthyroidism significantly lowers anti-Gal, but the possible increase of anti-Gal in patients with ophthalmopathy suggests anti-Gal may play a role in ophthalmopathy, or may reflect the euthryoid status of these patients. This trend needs further study.     

Patients with severe Graves' ophthalmopathy have a higher risk of relapsing hyperthyroidism and are unlikely to remain in remission

OBJECTIVE: To evaluate the relationship between severity of Graves' ophthalmopathy (GO) and relapse/remission rate of associated thyroid disease. PATIENTS AND METHODS: One hundred and fifty-eight patients with Graves' disease (GD) were seen within the first 6-12 months after the onset of GO and were followed for at least 18 months. During treatment, GO was classified as mild (n = 65) or severe course (n = 93) by severity and activity scores. All patients received standard anti-thyroid drug (ATD) treatment for 1 year, and in cases of relapse another cycle of ATD, thyroidectomy or radioiodine therapy. RESULTS: Following ATD treatment, 27 patients (42%) with a mild course of GO went into thyroid disease remission, while only seven (8%) patients with a severe course of GO achieved remission (P < 0.0001). Eventually, 32 patients (49%) with a mild course needed definitive thyroid therapy and the remaining 9% preferred another cycle of ATD. However, among patients with a severe GO course, 84% needed definitive therapy (P < 0.0001) and 8% opted for another course of ATD treatment. The probability of relapse could also be predicted by TBII levels 12 months after initiation of ATD therapy, as 96.8% of patients with TBII levels above 7.5 IU/l relapsed (odds ratio 24.3). CONCLUSION: Patients with severe GO and high TBII are unlikely to go into remission. This allows early decision-making regarding definitive treatment of the thyroid in GD patients with severe GO or very high TBII levels.     

Clinical results of anti-inflammatory therapy in Graves' ophthalmopathy and association with thyroidal autoantibodies

OBJECTIVE: Graves' ophthalmopathy (GO) is clinically associated with autoimmune thyroid disease, and autoantibodies to thyroidal antigens, especially to the TSH-receptor (TRAb), might be involved in the disease process. While there is mounting evidence that TRAb are associated with GO at the onset of the disease, so far no studies have looked at the association between thyroidal autoantibodies and the clinical outcome of GO therapy. The aim of this retrospective study was to evaluate whether TSH binding inhibitory immunoglobulins (TBII) and thyroid stimulating antibodies (TSAb) are still associated with the clinical activity and severity of GO after the completion of anti-inflammatory therapy. In addition, we wanted to elucidate whether thyroid peroxidase (TPO) or thyroglobulin (TG) autoantibodies (TPOAb and TGAb) are in any way related to GO. DESIGN PATIENTS AND MEASUREMENTS: Clinical activity score (CAS) and the severity of GO (modified NOSPECS score) were assessed in 108 patients with GO after steroid therapy and, if indicated, orbital irradiation. Patients were grouped according to their clinical presentation and autoantibody levels (TBII, TSAb, TPOAb and TGAb) were measured. After therapy for hyperthyroidism, all patients were clinically euthyroid but showed clear heterogeneity for GO 4-12 months after the end of anti-inflammatory therapy. Fifty-two patients had inactive GO, 41 had moderately active and 15 still had very active (non-responsive) GO. Concerning severity, 27 patients had mild GO, 64 moderately severe and 17 severe GO. RESULTS: TBII titres were still positive in 14 (93%) of 15 patients in the non-responsive group (CAS > 6) compared to 22 (42%) of 52 patients (P < 0.001) with post-therapeutic inactive GO (CAS 相似文献   

Thyroid autoantibody profiles in ophthalmic dominant and thyroid dominant Graves' disease differ and suggest ophthalmopathy is a multiantigenic disease

background Thyroid‐associated ophthalmopathy (TAO) occurs in 25–50% of patients with Graves’ disease (GD) and is occasionally seen in hypothyroid Hashimoto's disease or euthyroid individuals. The link between TAO and hyperthyroidism remains unclear. We hypothesized that qualitative or quantitative differences in thyroid antibodies might determine individual predisposition to these features. methods In a prospective study over 3 years, thyroid antibody levels were measured in all patients diagnosed at the Singapore National Eye Centre to have GD. These patients had no known history of thyroid disease, presented with eye complaints and diagnosis was made by an ophthalmologist. A total of 31 patients were identified. Antibody levels were compared against 71 consecutive patients referred to a thyroid clinic (TC) for thyrotoxic symptoms in whom the diagnosis of GD was confirmed by a thyroidologist. findings Thyroid autoantibody profiles of patients diagnosed at the ophthalmology centre (OC) and TC differed markedly. OC patients had significantly higher TSI (P = 0·003) but lower TPOAb (P = 0·008) and TgAb levels (P < 0·001). In contrast, TC patients had higher free T4 (P = 0·048) and higher TBII levels (P < 0·001). Antibody levels were correlated with four parameters of ophthalmopathy – chronic lid retraction, lid swelling, proptosis and extraocular myopathy (EOM). On univariate logistic regression analysis, TSI was a positive predictor and TPOAb and TgAb negative predictors of all four features. In the absence of TgAb, the odds ratios for individual TAO features ranged from 2·8 to 7·9, with corresponding values of 3·9–10·2 when TPOAb was absent. In stepwise logistic regression analysis, TSI was the strongest independent predictor of all aspects studied: lid fullness P = 0·001, proptosis P = 0·001, lid retraction P = 0·008, EOM P = 0·009. Among smokers, TPOAb were significantly lower (P = 0·044) but no association between smoking and the other antibodies was observed. interpretation The study demonstrates markedly different thyroid autoantibody profiles in newly diagnosed GD patients with ophthalmic dominant as opposed to thyroid dominant features. It suggests differing antibody patterns are associated with predisposition to hyperthyroidism and orbitopathy. In addition, an association between smoking and low TPOAb levels was noted.     

Thyroid-stimulating antibody is related to Graves' ophthalmopathy, but thyrotropin-binding inhibitor immunoglobulin is related to hyperthyroidism in patients with Graves' disease.

We investigated the relationship between thyroid function or ophthalmopathy of Graves' disease and thyrotropin receptor antibodies (TRAb) in 155 untreated patients with Graves' hyperthyroidism. All patients were examined by ophthalmologists, and underwent computed tomography of the orbit and measurement of serum free triiodothyronine (FT3), free thyroxine (FT4), thyrotropin-binding inhibitor immunoglobulin (TBII), and thyroid stimulating antibodies (TSAb). Patients were divided into three groups according to the presence of orbital fat increase (OFI) and extraocular muscle enlargement (EME): 57 patients without OFI and EMO formed the no Graves' ophthalmopathy (NGO) group; 55 patients with OFI but without EMO formed the OF group; 43 patients with EME with or without OFI formed the EM group. The FT3, FT4, and thyroid weight increased in the order of the EME, NGO, and OFI groups. TSAb increased in the order of the NGO, OFI, and EME groups, and TSAb was significantly greater in the EME and OFI than in the NGO group. TBII was not significantly different among the three groups, but was lower in EME than NGO. There was a significant positive correlation between TBII and FT3 or FT4 in all patients combined as well as in all three groups, but correlation between TSAb and FT3 or FT4 was very weak in all groups, and that between TSAb and FT3 was not significant in the EM group In the relationship between ophthalmopathy and TRAb, the sum of the scores of eyelid swelling, proptosis, and extraocular muscle enlargement was taken as a measure of the overall severity of the Graves' ophthalmopathy (GO). TSAb was significantly correlated with the GO score, but there was no correlation between TBII and GO scores. In conclusion, TSAb was correlated with ophthalmopathy but TBII was related to hyperthyroidism.     

血清甲状腺自身抗体、碘摄入量与Graves病发病及临床转归的关系

目的探讨血清甲状腺刺激性抗体（TSAb）、甲状腺刺激阻断性抗体（TSBAb）等甲状腺自身抗体、碘摄入量与Graves病（GD）甲状腺功能亢进症（甲亢）发病和转归的关系。方法测定3个不同碘摄入量地区63例临床甲亢患者的血清TSAb、TSBAb、促甲状腺激素结合抑制免疫球蛋白（TBⅡ）、甲状腺过氧化物酶抗体（TPOAb）和甲状腺球蛋白抗体（TGAb）,2年后随访。TSAb和TSBAb采用转染了重组人促甲状腺素受体的中国仓鼠卵巢细胞（rhTSHR—CHO细胞）生物法测定。结果初访GD甲亢患者TSAb、TBⅡ和TSBAb的阳性率分别为80．9％、61．7％和6．4％,TSAb和TBⅡ任-抗体阳性率为91．5％,显著高于对照组。TSAb和TBⅡ的一致率为59．6％。GD甲亢患者TSAb与TBⅡ（r=0．407）、甲状腺球蛋白（r=0、301）、甲状腺体积（r=0．317）正相关。初访碘过量地区GD甲亢患者TSAb阳性率（91．7％）显著高于轻度碘缺乏地区（66．7％）,3个地区GD患者TBⅡ、TPOAb、TGAb阳性率、活性和甲状腺体积无统计学差异。随访时患者分为甲状腺功能恢复组（G1）和未恢复组（G2）。G1组TSAb活性和甲状腺体积显著下降。当TPOAb滴度显著增高,且随访时继续保持高滴度时,甲状腺功能不易恢复。此时TSAb对甲状腺功能的影响降为次要因素。结论TSAb对GD甲亢的诊断和判断临床转归的意义大于TBⅡ,联合应用二者能提高GD甲亢患者促甲状腺激素受体抗体的检出率;GD甲亢的转归与TSAb、TPOAb浓度和甲状腺体积有关。     

Limited genetic susceptibility to severe Graves' ophthalmopathy: no role for CTLA-4 but evidence for an environmental etiology.

Graves' disease (GD) is an autoimmune thyroid disease (AITD) characterized by hyperthyroidism and by the occurrence of a distinctive ophthalmopathy (orbitopathy), which presents with varying degrees of severity. Graves' disease clusters in families but the importance of heredity in the pathogenesis of the associated ophthalmopathy is unclear. We have studied the family history of 114 consecutive, ethnically mixed patients with severe Graves' ophthalmopathy (GO). Patients were selected by unambiguous single ascertainment. Seventy-seven percent of patients were female and 59% smoked. The mean age at onset of their GD was 43 years (range 17-78 years). Forty-one patients (36%) had a family history of AITD, defined as a first- and/or a second-degree relative affected with either Graves' disease (GD) or Hashimoto's thyroiditis (HT). The segregation ratio for AITD in nuclear families in our ascertained Graves' ophthalmopathy families was 0.07 (0.12 in Caucasians only). Hence, the higher prevalence of AITD among relatives of Graves' ophthalmopathy patients agreed with the known genetic predisposition to AITD and this predisposition was stronger in women than in men. However, only 3 of the 114 patients had a family history of severe Graves' ophthalmopathy (all second-degree relatives) and the segregation ratio for GO was 0. These data did not support a major role for familial factors in the development of severe Graves' ophthalmopathy distinct from Graves' disease itself. In addition, we tested 4 candidate genes, human leukocyte antigen (HLA), tumor necrosis factor-beta (TNF-beta), CTLA-4 and the thyrotropin receptor (TSHR), for association with Graves' ophthalmopathy. These were negative except for the HLA and CTLA-4 genes, which were found to be weakly associated with GO giving similar relative risk (RR) as in GD patients without ophthalmopathy. These data suggested that environmental factors, rather than major genes, were likely to predispose certain individuals with AITD to severe Graves' ophthalmopathy. Smoking remains one example of such potential external insults.     

More on smoking habits and Graves' ophthalmopathy

Since a relationship between cigarette smoking and the occurrence of Graves' ophthalmopathy has been recently postulated, we reviewed the smoking habits of 1730 women, including subjects without thyroid disease, with nontoxic goiter (NTG), toxic nodular goiter or toxic adenoma (TNG), Hashimoto's thyroiditis (HT), Graves' disease without ophthalmopathy (GD) or with ophthalmopathy (GO). The prevalence of smokers in NTG, TNG and HT was about 30%, not different from that of controls. Smokers were 47.9% in GD and 64.2% in GO groups. The latter figures were highly different from those of the other groups and also from each other. The percentage of heavy smokers was higher in patients with more severe ophthalmopathy. No clear explanation for this phenomenon can be offered. The absence of a high prevalence of smokers among patients with non-toxic goiter, nonautoimmune hyperthyroidism and Hashimoto's thyroiditis, limits the impact that smoking might have had in the pathogenesis of goiter, hyperthyroidism and autoimmune phenomena of GD and GO.     

Clinical experience with a human thyroid cell bioassay for thyroid-stimulating immunoglobulin

A sensitive, specific, and practical bioassay for thyroid-stimulating immunoglobulin (TSI) is now available for clinical use. Fifty-seven of 61 patients with untreated hyperthyroid Graves' disease were TSI positive (sensitivity, 93%). TSI was undetectable in all normal subjects and in patients with Hashimoto's thyroiditis (without concurrent Graves' ophthalmopathy), nontoxic goiter, and toxic nodular goiter (specificity, 100%). The prevalence of TSI in serum declined after therapy, particularly during methimazole or propylthiouracil treatment. TSI correlated well with relapse or remission after antithyroid drug therapy. All 12 patients who were TSI negative at the time of discontinuing antithyroid drug therapy remained in remission (average follow-up of 10 months). TSI values in Graves' disease correlated better with thyroid dysfunction than with ophthalmopathy. Prenatal TSI activity tended to be higher in mothers of infants who developed neonatal Graves' disease than in at-risk mothers who delivered normal infants. However, there was considerable overlap between the two groups.     

The influence of the exon 1 polymorphism of the cytotoxic T lymphocyte antigen 4 gene on thyroid antibody production in patients with newly diagnosed Graves' disease.

Increasing evidence supports the genetic susceptibility for thyroid antibody (TAb) production in patients with autoimmune thyroid disease, and recently, it has been shown that the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene is most likely a major TAb susceptibility gene. To assess the relationship between exon 1 CTLA-4 gene polymorphism and TAb production, we genotyped 67 patients with newly diagnosed Graves' disease. Free thyroid hormones and TAb were measured, including thyroglobulin antibodies (TgAb), thyroid peroxidase antibodies (TPOAb), and thyroid-stimulating antibodies (TSAb). AA genotype was found in 25 patients, AG genotype in 34 patients, and GG genotype in 8 patients. G allele carrying genotypes showed significantly higher frequency of positive TPOAb (p < 0.005) and TgAb (p < 0.05) compared to AA genotype. Furthermore, the median values of TPOAb were significantly higher in the group with G allele (p < 0.002). However, the median values of TgAb and TSAb did not differ significantly between both groups and similarly, CTLA-4 genotype showed no association with serum free thyroxine (T(4)) and Graves' ophthalmopathy. In conclusion, our findings suggest that G allele carrying genotype of the CTLA-4 gene influences higher production of TPOAb and TgAb, and therefore, support the hypothesis that CTLA-4 gene plays a major role in TAb production.     

Antithyroid drugs inhibit radioiodine-induced increases in thyroid autoantibodies in hyperthyroid Graves' disease.

Methimazole (MMI) has been reported to affect prognosis in hyperthyroid Graves' disease patients treated with radioiodine (131I). In the present study, serum concentrations of thyroxine (T4), triiodothyronine (T3), thyroglobulin (Tg), thyrotropin-binding inhibitory immunoglobulin (TBII), thyroglobulin antibody (TgAb), and thyroid-peroxidase antibody (TPOAb) were measured serially for 1 year in patients with Graves' disease after 131I treatment either given alone (group 1, 41 patients) or followed by an antithyroid drug (group 2, 19 patients). The effect of antithyroid drugs on these parameters was analyzed retrospectively. Mean serum concentrations of T4 and T3 both decreased to normal within 3 months after 131I treatment in both groups. Serum Tg concentrations in group 1 showed significant transient increases (about four times the basal value) 1 month after 131I administration. Titers of TBII, TgAb, and TPOAb in group 1 also increased transiently after 131I treatment, with the maximum increase at 3 months. Antithyroid drugs significantly lessened 131I-induced increases in serum concentrations of Tg and all thyroid autoantibodies tested. One year after 131I treatment, 33 of 41 patients (80%) were euthyroid or hypothyroid in group 1; this was true for only 4 of 19 group II patients (22%). The results indicate that administering antithyroid drugs after 131I treatment reduced 131I-induced damage to the thyroid and reduced therapeutic efficacy of 131I in hyperthyroidism. Drug treatment also inhibited release of Tg and blunted 131I-induced increases in titers of thyroid autoantibodies.     

Usefulness of soluble ICAM-1 measurements for the evaluation of the disease activity and efficiency of therapy in patients with infiltrative Graves' ophthalmopathy

The authors studied serum levels of soluble intercellular adhesion molecule-1 (ICAM-1) in patients with progressive Graves' ophthalmopathy (GO), stable GO, hyperthyroid Graves' disease (GD) without GO and in healthy controls. The highest serum concentrations of sICAM-1 were observed in patients with progressive GO. In patients with stable GO and GD mean serum levels of sICAM-1 were elevated to a lesser degree. Mean serum concentrations of sICAM-1 decreased significantly during treatment of patients with the progressive GO parallel to the improvement of the eye changes. In patients with hyperthyroid GD serum levels of sICAM-1 decreased significantly after they had become euthyroid. Mean sICAM-1 level in the euthyroid GD was markedly decreased in comparison to the group of patients with progressive GO and slightly elevated when compared to stable GO. In conclusion, serum levels of sICAM-1 seems to be a good parameter of disease activity in progressive infiltrative GO. The decrease in sICAM-1 concentrations in patients with the progressive GO closely corresponds to the improvement of the clinical picture of the progressive GO.     

CORRELATION OF ORBITAL COMPUTED TOMOGRAPHY AND ANTIBODIES IN PATIENTS WITH HYPERTHYROID Graves''DISEASE

The purpose of this study was to elucidate the incidence of orbital changes in computed tomography, and the relationships of orbital changes with eye-muscle antibody (EMAb), thyrotrophin-binding inhibitor immunoglobulin (TBII), antithyroglobulin antibody (TgAb) and anti-thyroid microsomal antibody (MsAb), in 55 consecutive patients with hyperthyroid Graves' disease. EMAb was demonstrated by an immunoperoxidase technique. The results showed that the prevalence of orbital fat increase, extraocular muscle enlargement, lacrimal gland enlargement and optic nerve swelling were 54.5, 41.8, 21.8 and 16.5% respectively. There were 32.7% of patients without any orbital changes. The patients with extraocular muscle enlargement, lacrimal gland enlargement and optic nerve swelling had higher titres of EMAb than the patients without these orbital changes. The patients with lacrimal gland enlargement had a lower TBII index than those without. There was no difference in TgAb or MsAb between the patients with extraocular muscle enlargement, lacrimal gland enlargement, optic nerve swelling or orbital fat increase and those patients without these orbital changes. The patients with extraocular muscle enlargement, optic nerve swelling and orbital fat increase had a higher degree of exophthalmos than the patients without these orbital changes. EMAb was negatively correlated with TBII. However, there was no correlation between EMAb and TgAb or MsAb. The degree of exophthalmos was positively correlated with EMAb and negatively correlated with age. There was no correlation between exophthalmos and TBII, TgAb or MsAb. In conclusion, although the pathogenesis of orbital changes and hyperthyroidism is different, a close link between these two entities is suggested by the high incidence of orbital changes in hyperthyroid Graves' disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Association of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) gene polymorphism and non-genetic factors with Graves' ophthalmopathy in European and Japanese populations

OBJECTIVE: The development and severity of Graves' ophthalmopathy (GO) may result from a complex interplay of genetic and environmental factors. The aim of this study was to investigate the association of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) gene polymorphism and non-genetic factors (age, sex, cigarette smoking) with GO in two different populations, Polish-Caucasians and Japanese. DESIGN: We investigated the distribution of CTLA-4 A49G polymorphism in 264 Caucasian patients with Graves' disease (GD), of which 95 had clinically evident GO (NOSPECS class >or=3) and 319 Japanese patients with GD, of which 99 had ophthalmopathy. The control groups consisted of healthy Polish adults (n=194), Polish centenarians (n=51) and Japanese adults (n=112). RESULTS: Allele G and G/G genotype were significantly increased in Caucasian patients with GD (48% and 25% respectively) and in Japanese patients with GD (69% and 47% respectively) compared with control groups. There were no significant differences in the G allele and G/G genotype frequencies in GO patients compared with GD patients without ophthalmopathy. Multiple logistic regression analysis demonstrated that cigarette smoking (P=0.03, odds ratio (OR)=1.7) and age of onset of GD over 42 Years (P=0.08; OR=1.6) were contributing factors associated with susceptibility to GO in Polish patients. In Japanese patients, a younger age of onset of GD had an effect on the development of GO (P=0.02, OR=1.8). CONCLUSIONS: (i) Allele G and G/G genotype confer genetic susceptibility to GD; (ii) CTLA-4 A49G polymorphism is not associated with the development of GO; (iii) different non-genetic factors may contribute to GO in different populations.     

Graves'' ophthalmopathy in relation to cigarette smoking and ethnic origin

OBJECTIVE: We aimed to study the effect of cigarette smoking on the prevalence and severity of Graves' ophthalmopathy (GO). PATIENTS: One hundred and fifty-five newly diagnosed patients with Graves' disease (GD) were diagnosed clinically and by routine biochemical methods. Twenty-five per cent (39) were of Asian origin. METHODS: Eye signs were classified according to the American Thyroid Association Classification. A detailed smoking questionnaire and data from hospital notes were used to calculate an index of cigarette consumption. RESULTS: Thirty-four per cent of all patients had Graves' ophthalmopathy, and the prevalence in males (26%) and females (36%) did not differ significantly. There was a prevalence of 42% among Europeans compared to 7.7% in Asians (P = 0.0002). The overall risk for Europeans for developing Graves' ophthalmopathy was 6.4 (1.78-22.7 confidence interval) times higher than for Asians. Corrected for the ethnic factor the increased risk from smoking for Europeans was 2.4 (1.12-5.18, 95% confidence interval) times higher. There was a significant dose effect (P = 0.008). CONCLUSIONS: The present findings confirm an effect of cigarette smoking on Graves' ophthalmopathy and in addition show that Europeans have a substantially greater risk of developing Graves' ophthalmopathy than have Asians.     

Thyrotropin receptor autoantibodies are independent risk factors for Graves' ophthalmopathy and help to predict severity and outcome of the disease

OBJECTIVE: The objective of this study was to examine whether TSH-receptor antibody [TSH binding inhibitory antibodies (TBII)] levels are associated with the severity of Graves' ophthalmopathy (GO) over the entire course of the disease. METHODS AND PATIENTS: A total of 159 patients with GO were followed for 12-24 months. One year after the first symptoms of GO, all patients were classified into mild or severe GO according to their clinical manifestations. TBII were measured every 3 months after onset of GO. Receiver operating characteristic plot analysis was performed to assess the power to discriminate both patient groups by TBII (specificity >90%). RESULTS: TBII levels and prevalence at each time point during follow-up were significantly higher in patients with a severe course of GO compared with patients with a mild course of GO. Prognostic statements on the course of the disease were possible for about half of the GO patients at all time points (except the first). If at first presentation and at consecutive time points TBII levels were less than 5.7, 2.6, 1.5, 1.5, 1.5, and 1.5 IU/liter, the patients had a 2.3- to 15.6-fold higher chance of a mild course. If 5-8 months after GO onset and at consecutive time points TBII levels were above 8.8, 5.1, 4.8, 2.8, and 2.8 IU/liter, the patients had a 8.7- to 31.1-fold higher risk of a severe course. This relationship of TBII to the severity was independent from age and smoking. CONCLUSION: Follow-up measurements of TBII allow, in half of the patients, assessment of the prognosis of GO and, therefore, could be of additional help for the disease management.     

THE ACUTE CHANGES IN THYROID STIMULATING IMMUNOGLOBULINS,THYROGLOBULIN AND THYROGLOBULIN ANTIBODIES FOLLOWING SUBTOTAL THYROIDECTOMY*

The acute changes in thyroid adenylate cyclase stimulating immunoglobulins (TACSI), TSH binding inhibiting immunoglobulins (TBII), thyroglobulin (Tg) and thyroglobulin antibodies (TgAb) in serum after subtotal thyroidectomy were studied in thirteen patients with Graves' disease (GD) and thirteen patients with non-toxic goitre (NG). Prior to operation eight patients with GD were TACSI positive (mean ± SEM: 135·18%) and within 8 h following surgery TACSI increased and became positive in all thirteen patients (mean 172 ± 20%). There was a parallel increase in Tg and a decline in TgAb. A secondary rise in TACSI was observed 3–4 days after operation followed by a gradual fall which was associated with an increase in TgAb reaching a maximum 10 days after surgery. TACSI were still detectable 1 month postoperatively, but had disappeared by 3 months. In four of nine patients with GD TBII were present prior to operation. Immediately after surgery TBII decreased significantly (P < 0·05) and two of the four patients who were TBII positive became permanently negative, while the other two patients remained positive. A transient increase of the mean TBII levels was observed 5 days after surgery. Two of thirteen patients with NG were TACSI positive before operation and no significant changes were observed after surgery. The mean levels were significantly lower than in GD. Tg was measurable in eleven patients and showed a lower increase than in GD following surgery. TgAb were present in two patients prior to operation but disappeared in one and in the other one the changes following surgery were similar to the changes in GD.     

Why measure thyroglobulin autoantibodies rather than thyroid peroxidase autoantibodies?

Autoantibodies to thyroglobulin (TgAb) and thyroid peroxidase (TPOAb) are of immunoglobulin G (IgG) class and have high affinities for their respective autoantigens. Both autoantibodies are markers of thyroid autoimmunity and they can be measured by a variety of assays. From the clinical perspective, TgAb are less prevalent than TPOAb and less useful than TPOAb for prediction of thyroid dysfunction. Moreover, TgAb interfere with Tg measurements to monitor metastases in thyroid cancer. However, increasing evidence suggests that these TgAb provide a surrogate for Tg. In terms of disease pathogenesis, Tg has been suggested to play a role in Graves' ophthalmopathy. Pending further studies, TgAb epitopes could distinguish between individuals who are euthyroid or who have clinical disease. A final, intriguing reason for measuring and characterizing TgAb is the interest these autoantibodies have rekindled in their autoantigen. It is conceivable that Tg polymorphisms, combined with the explosive mix of iodine, TPO and H2O2 necessary for thyroid hormone synthesis, inadvertently provide the trigger for the autoimmune thyroid response.