We characterize the clinical and laboratory characteristics of 5 patients with Graves’ thyrotoxicosis whose serum free thyroxine (fT4) concentration decreased unexpectedly to low levels on conventional doses of carbimazole (CMZ) therapy. The initial fT4 mean was 40.0 pM, range 25-69 pM. Thyroid volume by ultrasound measured as mean 11 ml, range 9.0-15.6 ml. Initial TSI levels measured 1487% to >4444%. Serum fT4 fell to low-normal or hypothyroid levels within 3.6 to 9.3 weeks of initiating CMZ 5 to 15 mg daily, and subsequently modulated by fine dosage adjustments. In one patient, serum fT4 fluctuated in a “yo-yo” pattern. There also emerged a pattern of low normal/low serum fT4 levels associated with discordant low/mid normal serum TSH levels respectively, at normal serum fT3 levels. The long-term daily-averaged CMZ maintenance dose ranged from 0.7 mg to 3.2 mg. Patients with newly diagnosed Graves' hyperthyroidism who have small thyroid glands and markedly elevated TSI titres appear to be “ATD dose sensitive.” Their TFT on ATD therapy may display a “central hypothyroid” pattern. We suggest finer CMZ dose titration at closer follow-up intervals to achieve biochemical euthyroidism.
carbimazole ; Thyroid Stimulating Immunoglobulin ; Immunoglobulins, Thyroid-Stimulating ; Immunologic Tests ; Graves disease

BACKGROUND: Selenium (Se) shows potential benefit in Graves' disease (GD) especially those with active Graves' ophthalmopathy(GO).  
OBJECTIVES: To evaluate the efficacy of Se supplementation among patients with GD and GO.
METHODOLOGY: We performed a meta-analysis of trials evaluating the efficacy of Se supplementation among adult patients with GD and active GO, versus either placebo or an alternative drug, and on top of standard therapy. Results were presented as mean differences, standard errors, and 95% confidence intervals,and graphically presented as forest plots.Estimates were calculated using the inverse variance method for continuous variables and pooled using the fixed effects model. I2 and Chi2 tests were used to assess heterogeneity.
RESULTS: Only  two  trials  were  ultimately  included  in  the  analysis. Both studies totaled 197 participants with GD and non-severe  GO  on  standard  therapy,  and  compared  Se  supplementation to placebo. The only common outcomes of  interest  were  changes  in  TSH  receptor  antibody  (TRAB)  and thyroid peroxidase antibody (TPOAB) titers. We found no statistically significant difference in either TRAB (95% CI,-1.38  [-3.19,  0.44],  p=0.14)  or  TPOAB  (95%  CI,  36.66  [-32.56, 105.88], p=0.30) titers between Se and placebo groups on follow  up.However,our analysis was limited by the small number of included studies, a small sample size, and lack of other synthesizable outcomes.
CONCLUSION: This is the  first  meta-analysis  summarizing  the available data on Se supplementation in patients with GD and  non-severe  GO.We found no statistically significant differences in both TRAB and TPOAB titers between Se and placebo groups. We recommend larger studies to validate these findings. 

Thyrotropin-binding Inhibitory Immunoglobulin ; Graves Ophthalmopathy ; Selenium ; Iodide Peroxidase ; Immunoglobulins, Thyroid-stimulating ; Graves Disease ; Thyroid Microsomal Antibodies ; Autoantibodies ; Forests ; Thyroid Gland

It has been reported that receptor-bound blocking type TSH receptor antibody (TRAb) can be converted to the stimulating type by anti-human IgG antibodies. To evaluate the relationship between the conversion of receptor-bound blocking type TRAb to the stimulating type and the biological activity of blocking type TRAb, we compared converting activities of blocking type TRAb from 10 patients with primary nongoitrous hypothyroidism with both the doses of blocking type TRAb which show 50% inhibition of 125I-bTSH binding to the TSH receptor and those which show 50% inhibition of TSH-stimulated cAMP production in cultured rat thyroid cells (FRTL-5). The additions of anti-human IgG antibody to FRTL-5 cell-bound blocking IgGs resulted in the increase in cAMP production in a dose-dependent manner and the converting activities (percent increase of cAMP production) also depended on the doses of blocking IgGs. The converting activities were significantly correlated with the doses of blocking IgGs which showed 50% inhibition of 125I-bTSH binding to the TSH receptor (r = 0.71, p = 0.011). And these converting activities were also significantly correlated with the doses of blocking IgGs which showed 50% inhibition of TSH-stimulated cAMP increase (r = 0.81, p = 0.002), and were negatively correlated with thyroid stimulation blocking antibody activities (r = 0.58, p = 0.02). We have demonstrated that all cell-bound blocking type TRAb were converted to the stimulating type by anti-human IgG antibody and the degree of conversion was negatively correlated with the biological activity of blocking type TRAb.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult ; Aged ; Antibodies/*immunology ; Autoantibodies/*immunology ; Binding, Competitive ; Female ; Humans ; Immunoglobulin G/*immunology ; Immunoglobulins, Thyroid-Stimulating ; Middle Aged ; Receptors, Thyrotropin/*immunology ; Thyroid Gland/*immunology

We investigated the optimal condition of thyroid stimulating antibody(TSAb) assay using Chinese hamster ovary cells transfected with cDNA of human TSH receptor(TSHr-CHO) stably expressing functional TSH receptors. The extracellular cAMP responses of TSHr-CHO cells to the stimulation of bTSH or Graves' IgG were observed in three different incubation media. Stimulation indices of extracellular cAMP were higher when sucrose containing NaCl-free isotonic Hank's balanced salt solution(HBSS)(media A)was used as incubation media than those of NaCl-free hypotonic HBSS(media B) or those of NaCl containing isotonic HBSS(media C). The incubation of TSHr-CHO cells in media B caused marked increase in the basal cAMP level without concomittant fold-increase in the stimulated cAMP level at various doses of bTSH and Graves' IgG. Decreasing the stimulation indices of extracellular cAMP, use of media B failed to detect TSAb activities in two TSAb-positive Graves' IgG tested. In case of media C, extracellular cAMP responses are poor at 0.001 and 0.1U/L of bTSH and at all doses of Graves' IgG tested(0.5, 1, 5g/L). The incubation of TSHr-CHO cells in media B caused significant increase in the number of trypan blue-stained, nonviable cells(5.7+-1.5, 7.6+-1.9 and 8.5+-1.6% at 1, 2 and 3h of incubation, respectively; p<0.01) comparing to those incubated in media A or media C(about 2-3% in both media). Those decrease in the viability of TSHr-CHO cells when incubated in hypotonic incubation media may explain the decrease in the stimulation index of extracellular cAMP with the use of media B in contrast to the case of FRTL-5 cells. TSAb assay of 87 consecutive fresh Graves' patients with TSHr-CHO cells using media A detected TSAb activities in 90%(78 patients) of them, and moreover TSAb activities showed significant positive correlation with the pre-treatment serum T_3 and free T_4 levels of those patients. We conclude that TSAb assay with TSHr-CHO cells is a sensitive and physiologically relevant assay system to measure TSAb activities merely through measurements of extracellular cAMP provided that the cells are incubated in NaCl-free isotonic incubation media.
Animals ; Asian Continental Ancestry Group ; Biological Assay ; Cricetinae ; Cricetulus ; DNA, Complementary ; Female ; Humans ; Humans ; Immunoglobulin G ; Immunoglobulins, Thyroid-Stimulating ; Ovary ; Receptors, Thyrotropin ; Sucrose ; Thyroid Gland ; Thyrotropin

BACKGROUND: It has been known that most of thyroid stimulating antibodies (TSAbs) may interact with epitopes near N-terminal, and thyroid stimulation blocking antibodies (TSBAbs) near C-terminal on the extracellular domain of TSH receptor. However, many authors have reported different results about epitopes reacting with TSH receptor autoantibody (TRAb). TSBAbs inhibit thyroid stimulation of TSH and TSAbs at the receptor level. However, it has been reported that there are some TSBAbs which bind to the other sites, not TSH receptor, or block post-reeeptor process. These findings raise the possibility that TRAbs may be heterogeneous according to the mechanism of action. In order to investigate the heterogeneity of TRAb, we undertook immuno-precipitation using synthetic peptides of TSH receptor and measured TRAb activities by FRTL-5 cells and chimeric CHO cells. METHODS: We studied 102 patients with autoimmune thyroid disease (Graves disease 32, Hashimotos thyroiditis 29, atrophic thyroiditis 41) and 35 healthy persons. Three synthetic peptide fragments of TSH receptor were used to perform immunoprecipitation with serum or IgG of patients and healthy persons, TSAb and TSBAb activities were measured by FRTL-5 cells and CHO cells transfected with wild-type and 2 mutant TSH receptor cDNA (Mc2, Mc1+2). Mc2 and Mcl+2 were rnade to substitute amino acid residues of 90-165, 8-165 of the TSH receptor with corresponding residues of LH/CG receptor, respectively. RESULTS: Two out of 10 IgGs extracted from Graves disease and 2 out of 9 IgGs from atrophic thyroiditis had specific bidings over 0.84% in immunoprecipitation with peptide I (amino acid residue 35-50). Four out of 18 IgGs from Graves disease, 9 out of 41 IgGs from atrophic thyroiditis, and 6 out of 14 IgGs from Hashimotos thyroiditis had specific bidings over 0.84% in immunoprecipitation with peptide II (amino acid residue 317-332). Only 2 out of 10 IgGs from Graves disease had specific bidings over 0.84% in immunoprecipitation with peptide III (amino acid residue 341-358). When 10 IgGs extracted from Graves disease were reacted with wild-type, Mc2, and Mcl+2 CHO cells, 7 IgGs in wild-type and 4 IgGs in Mc2 had positive for TSAb activities. In 10 IgGs from atrophic thyroiditis, 5 in wild-type, 5 in Mc2, and 3 in Mcl+2 CHO cells had positive for TSBAb activities. In Hashimoto's thyroiditis, only 1 with hyperthyroidism had positive for TSAb activity in wild-type and 1 with hypothyroidism had positive for TSBAb activities in both of wild-type and Mc2 CHO cells. Therefore, patients with Graves disease were divided into at least 3 groups according to the TSAb activities measured by wild-type, Mc2, Mcl+ 2 CHO cells and TBII activities. And patients with atrophic thyroiditis were divided into at least 4 groups according to the TBII activities, TSBAb activities by wild-type, Mc2, Mcl+2 CHO cells and FRTL-5 cells. CONCLUSION: From these results, epitopes of TSH receptor reacting with TSAb or TSBAb in autoimmune thyroid disease may be scattered in the TSH receptor, although epitopes of TSAb tend to be near N-terminal and those of TSBAb near C-terminal. Graves disease or atrophic thyroiditis were divided into 3 or 4 groups according to the TBII and TRAb activities. Therefore, TRAb detected in autoimmune thyroid disease may be heterogenous.
Animals ; Antibodies, Blocking ; Autoantibodies* ; CHO Cells ; Cricetinae ; DNA, Complementary ; Epitopes ; Graves Disease ; Humans ; Hyperthyroidism ; Hypothyroidism ; Immunoglobulin G ; Immunoglobulins, Thyroid-Stimulating ; Immunoprecipitation ; Peptide Fragments ; Peptides ; Population Characteristics* ; Receptors, Thyrotropin* ; Thyroid Diseases* ; Thyroid Gland* ; Thyroiditis

Thyroid stimulating antibody which results in the development of hyperthyroidism and goiter in Graves' patients used to be measured by using rat thyroid cells, FRTL-5. However, this assay has disadvantages: decreased sensitivity due to differences in species, and fastidious culture conditions for FRTL-5 cells. Thus, we recently created stably transfected Chinese hamster ovary(CHO) cells containing the human TSH receptor(hTSHR-CHO) and developed optimal conditions for the measurement of thyroid stimulating antibody using hTSHR-CHO cells. In this study, to evaluate the clinical relevance of thyroid stimulating antibody measurement using hTSHR-CHO cells, we measured thyroid stimulating antibody activities of IgGs from Graves' disease and other thyroid disease using hTSHR-CHO cells, and compared to those of thyroid stimulating antibody assays using FRTL-5 cells. 1) The cut off value of positive thyroid stimulating antibody activity measured in hTSHR-CHO cells was 145%(above the mean +2SD) which was lower than 165% in FRTL-5 cells. The intra-assay and inter-assay variances were 3.9% to 9.0% and 12.7% to 1.6%, respectively. 2) Thyroid stimulating antibody activity was detected in 90% of patients with untreated Graves' disease when patients initially presented. Further, in patients seen initially but already under therapy, 75% had positive values if they were hyperthyroid but only 43% had IgGs with activity if they were euthyroid. Patients in clinical remission after therapy showed positive values in 23% of cases. Only 2 of 25 patients with Hashimoto's thyroiditis showed weak thyroid stimulating antibody activity, none of 18 patients with nodular nontoxie goiter, 1 of 15 patients with primary myxedema, and 2 of 33 control patients with no thyroid disease. Thus, the detection frequency and specificity of the assay with hTSHR-CHO cells was excellent for this type bioassay.3) The detection frequency of thyroid stimulating antibody activity by hTSHR-CHO cells assay system(90%) was higher than that by FRTL-5 cells assay system(66%) in untreated Graves' patients. Those two activities were positively correlated with each other(r=0.52, p<0.001). However, some IgGs showed discrepancy of the thyroid stimulating antibody activity measured in hTSHR-CHO cells and in FRTL-5 cells; 56 of 87 patients were positive in both cells system, 8 of 87 were negative in both cells system, 1 of 87 was only positive in FRTL-5 cells and 22 of 87 were only positive in hTSHR-CHO cell system. Thus, 73%(22/30) of IgGs showing negative values of thyroid stimulating antibody activities in FRTL-5 cells were detected its activities in hTSHR-CHO cells system.In summary, thyroid stimulating antibody assay with hTSHR-CHO cells exhibited so excellent sensitivity and specificity that this technique should be used for clinical practice as well as basic research.
Animals ; Antibodies ; Asian Continental Ancestry Group ; Cricetinae ; Cricetulus ; Female ; Goiter ; Graves Disease ; Humans ; Hyperthyroidism ; Immunoglobulin G ; Immunoglobulins, Thyroid-Stimulating ; Myxedema ; Ovary ; Rats ; Receptors, Thyrotropin ; Sensitivity and Specificity ; Thyroid Diseases ; Thyroid Gland ; Thyroiditis ; Thyrotropin

BACKGROUND: The Chinese hamster ovary cells transfected with human TSH receptor cDNA (hTSHR-CHO), expressing functional human TSH receptors, are known to be more sensitive in detection of thyroid stimulating antibodies than FRTL-5 cells. There has been no report on the usefulness of these cells to measure thyroid stimulation blocking antibody (TSBAb) activity which is frequently found in patients with primary myxedema, METHODS: We established the optimal assay condition of measurement of TSBAb using hTSHR-CHO cells, and simultaneously measured TSBAb activities with FRTL-5 cells and with hTSHR-CHO cells in 49 patients with primary myxedema, compared them with their thyrotropin binding inhibitor immunoglobulin (TBII) activities. RESULTS: 1) hTSHR-CHO cells specifically bound bTSH and were stimulated by bTSH in terms of cyclic AMP generation in a dose dependent manner. 2) Myxedema IgG suppressed TSH-stimulated cAMP production of hTSHR-CHO cells in a dose dependent manner reaching plateau at the concentration of I g/L. Normal pooled IgG has no suppressive action at the concentration of less than 1 g/L, but caused significant suppression at the concentration of greater than 1g/L. 3) TSBAb activities measured by hTSHR-CHO cells in 49 patients with primary myxedema were as follows: Four of 25 TBII-negative cases (16%) and 22 of 24 TBII-positive cases (92%) had TSBAb activities. Most of TSBAb positive patients (95%), especially in TBII positive cases, showed very high activities of more than 90%. 4) TSBAb activities measured by hTSHR-CHO cells and those by FRTL-5 cells were both positive in 24 patients (49%), both negative in 18 patients (37%), and were discrepant in 7 patients (14%). The TSBAb activities measured with hTSHR-CHO cells and those measured with FRTL-5 cells were significantly correlated (r=0.71, p< 0.01). 5) Forty five percent of patients with primary myxedema had all of 3 kinds of activities (TBII, hTSHR-CHO cell TSBAb, FRTL-5 cell TSBAb), 37% of them had none of 3 activities and 18% of them had 1 or 2 kinds of activities only. CONCLUSION: The usefulness of hTSHR-CHO cells in measurements of TSBAb activities were confirmed. The TSBAb activities of most patients with primary myxedema measured by hTSHR-CHO cells were concordant with those measured by FRTL-5 cells. However, a small subset of patients (18%) had discrepant results in assays of TSH receptor antibodies according to the differences in TSH receptors (rat, human and porcine) used in assay. Such discrepancy may be explained by heterogeneity in epitopes for blocking TSH receptor antibodies.
Animals ; Antibodies ; Asian Continental Ancestry Group* ; Cricetinae ; Cricetulus* ; Cyclic AMP ; DNA, Complementary ; Epitopes ; Female ; Humans ; Humans* ; Hypothyroidism* ; Immunoglobulin G ; Immunoglobulins ; Immunoglobulins, Thyroid-Stimulating ; Myxedema ; Ovary* ; Population Characteristics ; Receptors, Thyrotropin* ; Thyroid Gland* ; Thyrotropin