A 2013 European survey of clinical practice patterns in the management of Graves' disease.

OBJECTIVE: Management of Graves' disease (GD) in Europe was published in 1987. Aim of this survey was to provide an update on clinical practice in Europe, and to compare it with a 2011 American survey. DESIGN: Members of the European Thyroid Association (ETA) were asked to participate in a survey on management of GD, using the same questionnaire of a recent American survey. RESULTS: A total of 147 ETA members participated. In addition to serum TSH and free T4 assays, most respondents would request TSH-receptor autoantibody (TRAb) measurement (85·6%) and thyroid ultrasound (70·6%) to confirm aetiology, while isotopic studies were selected by 37·7%. Antithyroid drug (ATD) therapy was the preferred first-line treatment (83·8%). Compared to the previous European survey, Europeans currently more frequently use TRAb measurement and thyroid ultrasound for diagnosis and evaluation, but first-line treatment remains ATDs in a similar percentage of respondents. Current clinical practice patterns differ from those in North America, where isotopic studies are more frequently used, and radioiodine (RAI) still is first-line treatment. When RAI treatment is selected in the presence of mild Graves' orbitopathy and/or associated risk factors for its occurrence/exacerbation, steroid prophylaxis is frequently used. The preferred ATD in pregnancy is propylthiouracil in the first trimester and methimazole in the second and third trimesters, similar to North America. CONCLUSIONS: Significant changes in clinical practice patterns in Europe were noted compared to the previous European survey, as well as persisting differences in diagnosis and therapy between Europe and North America.

Thyroid cancer yield in patients with Graves' disease.

The management of thyroid nodules in patients with Graves' disease remains an issue both of concern and controversy for those who care for these patients. At one time, thyroid cancer in patients with thyrotoxicosis was considered to be extremely rare, but this perception has proven to be incorrect. Several studies have demonstrated both an increased incidence of nodules and of thyroid cancer in patients with Graves' disease, with cancer rates varying from as low as 1% to as high as 9% of cases. These divergent estimates of malignancy rates in Graves' disease have predictably led to variability in management recommendations. Considerable controversy also exists as to whether or not thyroid cancer behaves more aggressively in patients with Graves' disease. Anecdotal experience and a number of studies have suggested an increased aggressiveness of papillary and follicular thyroid cancer in patients with Graves' disease, but these findings are not universal. Underlying both issues of the incidence and aggressiveness of thyroid cancer is the role of thyrotropin (thyroid stimulating hormone, TSH) in the development and stimulation of thyroid cancer. The association between TSH and thyroid cancer has long been known. TSH has a central role in thyroid growth and normal functioning and appears to play a similar part in the growth and development of thyroid cancer. The close relationship of TSH to the stimulating TSH-R antibodies (TSH-R AB) seen in Graves' disease has led to the perception that thyroid cancer occurring in the setting of Graves' disease may become more aggressive as a result of stimulation by these autoantibodies. This article will summarize the existing literature pertaining to thyroid cancer in Graves' disease, and suggest an evidence-based approach to the management of these patients.

Nuclear localization of thyroid transcription factor-1 correlates with serum thyrotropin activity and may be increased in differentiated thyroid carcinomas with aggressive clinical course.

Thyroid transcription factor 1 (TTF-1) is essential for thyroid differentiation and regulates expression of thyroglobulin, thyroid peroxidase, sodium/iodide symporter, and thyrotropin receptor (TSH-R) genes. Because thyrotropin (TSH) upregulates these same genes, we hypothesized TSH-R activation might increase TTF-1 and that TTF-1 might be differentially expressed in benign and malignant thyroid disease. TTF-1 expression and sub-cellular localization were determined by immunohistochemistry in 62 thyroid carcinomas, 15 benign lesions, and 2 normal thyroids. Nuclear TTF-1 was detected in benign (77%) and malignant lesions (69%), with similar intensity in both (1.1+/-0.19 versus 1.0+/-0.10). Nuclear TTF-1 staining correlated with the effective serum TSH level (p = 0.02) and patient age (p < 0.05). Nuclear TTF-1 was detected in 35 papillary thyroid carcinomas (PTC), of which 23% developed recurrent or persistent disease, and was absent from 18 PTC, of which only 6% recurred (p = 0.06). We conclude that nuclear TTF-1 correlates with serum TSH activity, increases with age, and may be increased in persistent or recurrent PTC.

The effect of antithyroid drug pretreatment on acute changes in thyroid hormone levels after (131)I ablation for Graves' disease.

Acute changes in thyroid hormone levels before and after radioiodine therapy for Graves' disease were compared in 42 patients randomized to receive either antithyroid drug pretreatment or no pretreatment. Five patients (11.9%), including 3 in the pretreatment arm and 2 in the no pretreatment arm experienced a late exacerbation of thyrotoxicosis after radioiodine therapy. The majority (19 of 21, 90.5%) of pretreated patients experienced a transient increase in free T(4) and free T(3) after discontinuation of antithyroid drugs, with little further elevation after radioiodine therapy. After stopping antithyroid drugs and before radioiodine administration, mean serum free T(4) values rose from 14.7 +/- 6.9 to 21.6 +/- 12.1 pmol/L, representing a 46.9% increase, whereas serum free T(3) levels rose from 4.9 +/- 1.7 to 8.1 +/- 6.3 pmol/L, representing a 65.3% increase. The average pretreated patient experienced a 52.4% increase [95% confidence interval (CI), +26.4% to +78.5%] in free T(4) and a 61.8% increase (95% CI, +23.5% to +100.0%) in free T(3). Conversely, the majority (19 of 21, 90.5%) of nonpretreated patients experienced a rapid decline in thyroid hormone levels after radioiodine treatment. Over the 14 days after radioiodine therapy mean free T(4) values in nonpretreated patients fell from 85.8 +/- 60.4 to 58.0 +/- 76.5 pmol/L, representing a 32.4% decrease, whereas mean free T(3) levels fell from 16.1 +/- 8.0 to 10.8 +/- 11.1 pmol/L, representing a 32.9% decrease. The average nonpretreated patient experienced a 20.6% decrease (95% CI, -47.3% to +7.0%) in free T(4) and a 24.3% decrease (95% CI, -1.2% to -47.4%) in free T(3) during this time period. Excluding 2 patients with a late exacerbation after radioiodine, 19 nonpretreated patients experienced a decrease in mean free T(4) values from 76.8 +/- 46.6 to 36.6 +/- 19.8 pmol/L, representing a 52.3% decrease, whereas mean free T(3) levels fell from 15.5 +/- 7.7 to 7.8 +/- 3.6 pmol/L, representing a 49.7% decrease. The average decrease in free T(4) levels among this subgroup of patients was 30.1% (95% CI, -4.6% to -55.6%), whereas the average decrease in free T(3) was 34.4% (95% CI, -13.7% to -55.1%). High levels of TSH receptor autoantibodies at diagnosis were associated with an acute worsening of thyrotoxicosis after stopping antithyroid drug pretreatment. We conclude that pretreatment with antithyroid drugs does not protect against worsening thyrotoxicosis after radioiodine, but may allow such patients to start from a lower baseline level should an aggravation in thyrotoxicosis occur. The findings support the recommendation that most patients with Graves' disease do not require antithyroid drug pretreatment before receiving radioiodine.

Serum thyroglobulin measurement. Utility in clinical practice.

Serum thyroglobulin measurement has greatly facilitated the clinical management of patients with differentiated thyroid cancer and a variety of other thyroid disorders. Thyroglobulin autoantibodies remain a significant obstacle to the clinical use of thyroglobulin measurement. The interpretation of any given thyroglobulin value requires the careful synthesis of all pertinent clinical and laboratory data available to the clinician. The diagnostic use of rhTSH-stimulated thyroglobulin levels has greatly facilitated the follow-up of low-risk patients with thyroid cancer. Although the measurement of thyroglobulin mRNA from peripheral blood is likely to affect the future management of these patients, it is expected that serum thyroglobulin measurement will continue to have a principal role in the care of patients with differentiated thyroid cancer.

Expression of the sodium iodide symporter and thyroglobulin genes are reduced in papillary thyroid cancer.

Altered expression of the gene encoding the sodium iodine symporter (NIS) may be an important factor that leads to the reduced iodine accumulation characteristic of most benign and malignant thyroid nodules. Both up- and down-regulation of NIS gene expression have been reported in thyroid cancer using several different methods. The goal of the present study was to accurately identify alterations in NIS gene expression in benign and malignant thyroid nodules using an accurate real-time quantitative RT-PCR assay system. Total RNA was prepared from 18 benign thyroid nodules, 20 papillary thyroid cancers, and 23 normal thyroid samples from 38 subjects. Quantitative RT-PCR was used to measure NIS and thyroglobulin (TG) mRNA expression in normal thyroid tissue and in each nodular tissue sample. Papillary thyroid cancer samples had significantly lower NIS mRNA expression (72 +/- 41 picogram equivalents [pg Eq]), than did benign nodules (829 +/- 385 pg Eq), or normal tissues (1907 +/- 868 pg Eq, P = 0.04). Most important, in the paired samples, NIS gene expression was decreased in each papillary thyroid cancer compared with normal tissue (69% median decrease; range, 40-96%; P = .013). Eleven of the 12 benign nodules also demonstrated lower NIS gene expression than the normal tissue (49% decrease; range, 2-96%; P = .04). Analysis of the paired samples demonstrated that Tg mRNA expression was significantly lower in each of the thyroid cancer samples than in corresponding normal tissue (759 +/- 245 pg Eq vs. 1854 +/- 542 pg Eq, P = .03). We have demonstrated a significant decrement in NIS gene expression in all papillary thyroid cancers and in over 90% of benign nodules examined compared with adjacent normal thyroid tissue, using a highly accurate quantitative RT-PCR technique. Similarly, thyroid cancers demonstrated significantly lower TG mRNA expression than corresponding normal thyroid. Reduced NIS expression may be an important factor in the impairment of iodine-concentrating ability of neoplastic thyroid tissues.

Diagnosis and management of the autonomously functioning thyroid nodule: the Walter Reed Army Medical Center experience, 1975-1996.

In order to characterize the clinical and laboratory features of autonomously functioning thyroid nodules (AFTNs), and to assess optimal diagnosis and management of patients with this disorder, we performed a retrospective analysis of 49 such patients over a 22-year period encompassing January 1975 to November 1996. The following data were analyzed: thyroid hormone levels, thyroid scintiscan, radioiodine uptake, fine-needle aspiration biopsy, triiodothyronine (T3) suppression testing, thyrotropin-releasing hormone (TRH) stimulation test, and thyroid ultrasound. Clinical outcomes assessed included persistent hyperthyroidism, hypothyroidism, and nodule shrinkage after treatment, or in patients followed without definitive therapy, nodule growth, spontaneous degeneration, and progression to hyperthyroidism. Biochemical hyperthyroidism, often subclinical, was found in 73.5% of patients at presentation and in an additional 24.4% of patients during subsequent follow-up. The introduction of sensitive thyrotropin (TSH) testing during the period of study resulted in a decrease in the use of the T3-suppression test and TRH stimulation test from 100% and 20%, respectively, in the period from 1976-1980, to 4% each in the period from 1991-1996. T3-thyrotoxicosis occurred in 12.2% of patients. Thyrotoxicosis at any time during the course of follow-up was positively correlated with nodule size at diagnosis. Definitive therapy, used in 42.8% of patients, consisted of radioiodine ablation (38.1%) or thyroidectomy (61.9%). No patient had recurrence of thyrotoxicosis after definitive therapy, but 25% became hypothyroid. During follow-up for a mean of 30.9 months, nodules enlarged in 25% of patients overall, or 33% of patients not receiving definitive therapy. Cystic degeneration was documented in 26.5% of patients, although this change rarely reversed subclinical hyperthyroidism. The diagnosis of an AFTN requires a demonstration of TSH-independent nodular hyperfunction. The introduction of sensitive TSH assays has simplified the evaluation of AFTN patients and revealed a high prevalence of subclinical thyroid hyperfunction in this disorder. In view of current increased awareness of adverse consequences associated with subclinical hyperthyroidism and the rarity of spontaneous resolution of hyperthyroidism in AFTN patients (despite a propensity for spontaneous hemorrhage), definitive therapy is recommended. Both radioiodine and hemithyroidectomy have high cure rates and a low posttreatment incidence of hypothyroidism.

Clinical features associated with an increased risk of thyroid malignancy in patients with follicular neoplasia by fine-needle aspiration.

The application of fine-needle aspiration (FNA) to the evaluation of the thyroid nodule has greatly enhanced the ability of the clinician to appropriately select patients for thyroidectomy. However, despite extensive experience with thyroid FNA, the cytological distinction of benign from malignant follicular neoplasia remains problematic. As a result, most patients with FNA findings of a follicular neoplasm are referred for thyroidectomy. The goal of the present study was to develop clinical criteria capable of predicting malignancy in patients with an FNA diagnosis of follicular neoplasm. Among 1121 patients undergoing thyroid FNA at two large teaching centers during the period 1990 to 1995, 149 patients had cytological findings consistent with a follicular neoplasm. Among 103 patients referred for thyroidectomy, 22 (21%) were found to have a malignancy in the biopsied nodule. Among patients subjected to thyroidectomy, the risk of malignancy was significantly higher when follicular neoplasia was present in a male (43% vs. 16% for females, p = 0.007), when the nodule was greater than 4 cm to palpation (40% vs. 13% for nodules less than 4 cm, p = 0.03), or when the nodule was judged to be solitary by palpation (25% vs. 6% for a dominant nodule in a multinodular goiter, p = 0.02). Bayesian analysis of the data reveals that after an FNA showing a follicular neoplasm, the risk of malignancy in males with large nodules was nearly 80%, compared with a rate of only 3% in females with small nodules. These results suggest that clinical features including gender, nodule size, and character of the gland by palpation can be systematically integrated into the decision analysis, thereby improving the selection of patients for surgical referral.

Immunodetection of manganese superoxide dismutase in cultured human retroocular fibroblasts using sera directed against the thyrotropin receptor.

The identification of antigenic targets in the retroocular autoimmune response of Graves' ophthalmopathy is likely to increase our understanding of mechanisms underlying this disorder. While a number of putative autoantigens have been identified on the basis of molecular weight or cell of origin, a determination of the significance of these antigens is contingent upon an identification of the amino acid sequence. Our group has previously identified immunoreactive retroocular fibroblast (ROF) proteins recognized by thyrotropin receptor (hTSH-R) antisera (anti-p1), at molecular weights of 95, 71, 41, and 14-25 kDa. In the present study, proteins detected by anti-p1 and visualized by Ponceau staining were isolated and processed for microsequencing. Ponceau staining revealed dense bands at molecular weights of 14 and 23 kDa, and a weak band at 41 kDa. N-terminal sequencing was performed on the prominent band at approximately 23 kDa, showing it to be manganese superoxide dismutase (MnSOD), a mitochondrial enzyme responsible for protection against oxygen free radical-associated cellular damage. Sequence comparison of MnSOD to the hTSH-R peptide, p1, revealed a linear segment of amino acid homology. Preincubation of anti-p1 with p1 blocked immunodetection of the 23 kDa band corresponding to MnSOD, and immunoprecipitation of ROF protein using anti-pi yielded protein recognized by anti-MnSOD. Autoimmunity against human recombinant MnSOD was further assessed by ELISA. Patients with Graves' disease (n = 53) had significantly higher ELISA indices than normal control subjects (n = 29), while patients with Hashimoto's thyroiditis had intermediate values. These results document MnSOD autoantibodies in patients with Graves' disease and suggest that this may result from an immune cross-reactivity between MnSOD and the TSH-receptor.

Superoxide radical production stimulates retroocular fibroblast proliferation in Graves' ophthalmopathy.

Retroocular fibroblast proliferation is believed to be a key component in the pathogenesis of Graves' ophthalmopathy. In the present study, we assessed the ability of superoxide radicals, generated using the xanthine oxidase/hypoxanthine system to induce cellular proliferation in cultured human retroocular fibroblasts obtained from two patients with severe Graves' ophthalmopathy and two control patients undergoing corrective eye surgery. In tissue obtained from patients with Graves' ophthalmopathy, fibroblast proliferation, as assessed by [3H]-thymidine incorporation, was induced by superoxide radicals in a dose-dependent manner. Xanthine oxidase or hypoxanthine alone had no proliferative effect, and control retroocular fibroblasts showed no proliferation in response to superoxide generation. Preincubation with the antithyroid drug methimazole, at concentrations ranging from 0-25 microM, prevented superoxide-induced fibroblast proliferation in a dose-response pattern. Preincubation with the xanthine oxidase inhibitor, allopurinol (1.0 mM) or the antioxidant nicotinamide (10 microM) also inhibited superoxide-induced fibroblast proliferation, whereas propylthiouracil (10 microM) had little effect. These studies suggest a pathway through which oxygen free radicals may contribute to the retroocular fibroblast proliferation observed in patients with Graves' ophthalmopathy.

Fine needle aspiration of thyroid nodules. Determinants of insufficiency rate and malignancy yield at thyroidectomy.

OBJECTIVE: To evaluate patient- and practice-specific determinants of the thyroid nodule fine needle aspiration (FNA) insufficiency rate and malignancy yield at a tertiary-care teaching hospital. STUDY DESIGN: All FNAs of thyroid nodules performed from August 1990 to October 1993 at the Walter Reed Army Medical Center Endocrinology Clinic were reviewed and the results analyzed for correlation with surgical outcome, scintiscanning result and operator experience. Provider-specific factors influencing the FNA insufficiency rate, surgical referral pattern and malignancy yield were evaluated. RESULTS: A total of 504 aspirations in 422 patients with thyroid nodules were included in the analysis. The sensitivity of FNA for detecting malignancy was 80%, specificity was 73.2%, and accuracy was 75.2%. A significant negative correlation was found between recent aspirator experience and the insufficiency rate. Repeat aspiration of nodules previously yielding benign cytology increased the malignancy yield. Surgical excision of nodules with insufficient aspirations gave a low malignancy yield, and aspiration of nodules that were "hot" on scintiscanning rarely yielded false positive FNA results. CONCLUSION: Specific limitations of thyroid nodule FNA include a large number of aspirates containing insufficient cytologic material and a variable malignancy yield. Specific recommendations based on the findings in this report are: the establishment of uniform criteria for judging specimen adequacy, the performance of repeat aspiration on thyroid nodules with previously benign aspirates, the abandonment of scintiscanning in the routine management of thyroid nodules and a conservative approach to clinically indolent nodules repeatedly found to have scant cellularity on FNA. Based on these findings, an algorithm for the diagnostic evaluation of a solid thyroid nodule can be constructed.

Immunoglobulins from Graves' disease patients stimulate phospholipase A2 and C systems in FRTL-5 and human thyroid cells.

We have studied the effects of immunoglobulin G from Graves' disease patients on phospholipase A2 (PLA2) and C(PLC) systems in FRTL-5 and human thyroid cells. Immunoglobulin G (IgG) from Graves' disease patients stimulated arachidonic acid (AA) release in a time- and dose-dependent manner. In FRTL-5 thyroid cells, removal of external calcium had no significant effect on the IgG (20 micrograms/ml)-induced AA release in FRTL-5 thyroid cells. U-73122 (3 mumol/l), a PLC inhibitor, and quinacrine (100 mumol/l) but not U-26384 (5 mumol/l), PLA2 inhibitors, blocked the IgG-induced (20 micrograms/ml) AA release in FRTL-5 thyroid cells. Immunoglobulin G (100 micrograms/ml) also stimulated accumulation of inositol-1,4,5-triphosphate (IP3) in a time- and dose-dependent (20-300 micrograms/ml) manner in FRTL-5 cells. Immunoglobulin G from Graves' disease patients induced a significant increase of IP3 production (p = 0.01) compared to IgG from normal subjects. Removal of external calcium had no significant effect on the IgG-induced IP3 production. The PLC inhibitor U-73122 completely blocked IgG-induced IP3 production from FRTL-5 thyroid cells. Also, in human thyroid cells, IgG from Graves' disease patients induced a significant increase of AA release (p = 0.001) and IP3 production (p = 0.004) compared to the IgG from normal subjects. These data indicate that IgG from Graves' disease patients induced PLA2 activity that was PLC dependent, a pattern referred to as sequential activation. Our studies suggest that IgG from Graves' disease patients activates PLA2 and PLC systems in FRTL-5 and human thyroid cells. These signal transduction pathways could be involved in the pathogenesis of Graves' disease and future studies are warranted to investigate this area.

Evaluation and management of the solid thyroid nodule.

A tremendous effort has been applied to the determination of optimum management strategies in patients with solid thyroid nodules. The systematic acquisition of experience with historical and physical examination features suggestive of malignancy and the careful crafting of noninvasive techniques to assist in this determination have each contributed to improvements in the safety and cost-effectiveness of management in these patients. Despite this progress, significant difficulties await resolution, including the preponderance of patients still subjected to thyroidectomy for benign follicular lesions and the reluctance of clinicians to abandon the use of diagnostic techniques that offer little useful information, such as routine scintillation scanning and diagnostic trials of suppressive therapy. An exciting area now in its infancy is the identification of useful molecular markers for the selection of the few malignant thyroid nodules from among the multitudes of benign lesions. As is true in diagnostic evaluation, uncertainty continues to be experienced by clinicians charged with proper nonsurgical management of the solid thyroid nodule. The use of thyroid hormone suppressive therapy, once considered a cornerstone of conservative management, has been cast in a new light revealing both the limited utility and potential harm associated with this approach. These uncertainties should not be viewed as impediments, but rather, as opportunities for growth, as it is controversy rather than complacency that stimulates new investigation and fresh approaches to old problems.

Thyrotropin receptor T cell epitopes in autoimmune thyroid disease.

The human TSH receptor represents the primary target of thyroid-stimulating immunoglobulins responsible for the hyperthyroidism of Graves' disease. In the present series of investigations, the distribution of T cell epitopes has been mapped using synthetic peptides spanning the entire extracellular region of the human TSH receptor. In vitro proliferative responses of the mononuclear cells were measured using flow cytometric analysis of bromodeoxyuridine incorporation into nuclei. In 8 of 11 samples from patients with Graves' disease, at least one (and up to 9) regions of the human TSH receptor induced proliferation, with the mean stimulation index being 39.8 +/- 47.3. No single universal stimulatory peptide was identified. In contrast, stimulation was not observed in three control subjects, while one control subject showed minimal stimulation (index of 5.7) to peptides encompassing a limited area (amino acids 31-65). The immunodominant epitope of patients with recent-onset Graves' disease was localized between amino acids 271 and 365, whereas the immunodominant epitope of patients with disease duration greater than 1 year localized between amino acids 91 and 215. We conclude that the bromodeoxyuridine incorporation method is a useful and important tool for detecting antigen-induced lymphocyte proliferation. The TSH receptor-specific T cells from different Graves' disease patients recognize variable distinct sites within the extracellular region of the TSH receptor, and the immunodominant epitope apparently shifts toward the N-terminus of the receptor protein during the course of treated Graves' disease.

Discontinuing antithyroid drug therapy before ablation with radioiodine in Graves disease.

OBJECTIVE: To determine the relative effects on thyroid hormone levels of discontinuing antithyroid drug therapy and subsequent ablation with radioiodine in patients with hyperthyroid Graves disease. DESIGN: A clinical trial with a prospective analysis of the relative change in thyroid hormone levels over time in response to therapy in two study groups. SETTING: An outpatient endocrine clinic at a tertiary care hospital. PATIENTS: 21 patients with a clinical diagnosis of hyperthyroid Graves disease scheduled to receive ablation therapy with radioiodine (131I): 17 patients were pretreated with antithyroid drugs, and 4 were not. METHODS: Antithyroid drugs were stopped 6 days before radioiodine therapy. Patients were monitored clinically and biochemically with measurement of free and total levels of thyroxine (T4) and triiodothyronine (T3) on days -6, -3, -1; the day of radioiodine therapy; and days 1, 2, 3, 4, 5, 7, and 14. RESULTS: Before radioiodine treatment and compared with baseline measurement, the mean increase in free T4 levels after discontinuation of antithyroid therapy was 86% (95% CI, 16.1% to 156%), with a concurrent mean increase in free T3 levels of 71.6% (CI, 31% to 112%). Radioiodine therapy resulted in a mean decrease in free T3 levels of 28.7% (CI, -44.1% to -13.2%), a mean decrease in total T3 levels of 22.9% (CI, -39.4% to -6.4%), and stability in free and total T4 levels rather than aggravation of thyrotoxicosis. A smaller group of patients not receiving antithyroid drugs experienced a course qualitatively similar to that of pretreated patients after 131I treatment, with a mean reduction in free T4 levels of 39.8% (CI, -69.9% to -9.7%) and a mean decrease in free T3 levels of 49.4% (CI, -93.7% to -5.1%). CONCLUSION: Short-term increases in thyroid hormone levels in patients with Graves disease receiving radioiodine ablation occur primarily as a result of discontinuing antithyroid therapy rather than as a result of treatment with 131I. Stability or decrease in thyroid hormone levels, rather than further elevation, occurs during the 2-week interval after ablation therapy with 131I. Antithyroid drug therapy before radioiodine ablation may have little effect on the short-term biochemical course after 131I therapy for Graves disease. The homogeneity of our sample regarding age, diagnosis, and general health may prevent application of these findings to other populations without further study.

TSH receptor gene expression in retroocular fibroblasts.

RNA was isolated from fibroblasts from the retroocular area, from endomysial fibroblasts obtained from orbital lateral rectus muscle, and from abdominal skin fibroblasts. The RNA was reverse transcribed into cDNA which was then used as a template for PCR with primers encompassing a portion (nucleotides 989-1235) of the extra-cellular domain of the human TSH receptor (hTSH-R). A definite 247 BP product was detected from fibroblast RNA by ethidium bromide staining, and was confirmed by hybridization with labelled hTSH-R cDNA. The product had homology with the known TSH-R cDNA. These studies indicate that human fibroblasts can express hTSH-R, and they suggest that a cross reactive immunologic response between anti-hTSH-R and these fibroblast TSH receptors may play a role in the genesis of Graves' ophthalmopathy.

Thyrotropin receptor antisera for the detection of immunoreactive protein species in retroocular fibroblasts obtained from patients with Graves' ophthalmopathy.

Autoimmunity against the TSH receptor (hTSH-R) is known to be the proximate cause of thyroidal activation in Graves' disease, but has not been definitively linked to extrathyroidal manifestations of this disorder, such as ophthalmopathy and pretibial myxedema. In an effort to increase our knowledge concerning mechanisms responsible for Graves' ophthalmopathy, we used antiserum directed against a highly immunogenic portion of the hTSH-R (amino acids 352-367; P1) to assess the presence of this receptor or immunologically related protein in cultured human retroocular fibroblasts obtained from patients with Graves' ophthalmopathy. Immunoenzymatic and immunofluorescent studies revealed specific staining of both cytoplasmic and cell membrane-associated protein in discrete vesicles. To further evaluate the immunoreactive species present in these cells, immunoblotting experiments were performed using hTSH-R-specific antisera (anti-P1) and sera obtained from patients with Graves' disease. Several protein bands were identified using both anti-P1 and Graves' disease patient sera, including species at mol wt of 95, 71, and 18 kilodaltons, the possible significance of which is discussed. The results support the hypothesis that immunity against the hTSH-R or related proteins contributes to the ophthalmopathy of Graves' disease.