Thyroid-stimulating antibody and TSH-binding inhibitor immunoglobulin in 277 Graves' patients and in 686 normal subjects

Short review: novel concepts in the approach to patients with amiodarone-induced thyrotoxicosis

INTRODUCTION

Amiodarone-induced thyrotoxicosis is associated with high morbidity and mortality rates. The approach to this condition is widely variable across different medical specialists and even among expert endocrinologists. As a matter of fact, the approach to amiodarone-induced thyrotoxicosis has always been considered difficult, due to diagnostic uncertainties easily resulting in missteps, and therapeutic challenges easily resulting in unresponsiveness or slow-responsiveness to the administered drugs.

PURPOSE

Our purpose is to review novelties emerged during the last years about this condition, with the aim to provide novel insights on the diagnostic and therapeutic management of this challenging condition.

Differential Diagnosis of Thyrotoxicosis by Machine Learning Models with Laboratory Findings

Differential diagnosis of thyrotoxicosis is essential because therapeutic approaches differ based on disease etiology. We aimed to perform differential diagnosis of thyrotoxicosis using machine learning algorithms with initial laboratory findings. This is a retrospective study through medical records. Patients who visited a single hospital for thyrotoxicosis from June 2016 to December 2021 were enrolled. In total, 230 subjects were analyzed: 124 (52.6%) patients had Graves’ disease, 65 (28.3%) suffered from painless thyroiditis, and 41 (17.8%) were diagnosed with subacute thyroiditis. In consideration that results for the thyroid autoantibody test cannot be immediately confirmed, two different models were devised: Model 1 included triiodothyronine (T3), free thyroxine (FT4), T3 to FT4 ratio, erythrocyte sediment rate, and C-reactive protein (CRP); and Model 2 included all Model 1 variables as well as thyroid autoantibody test results, including thyrotropin binding inhibitory immunoglobulin (TBII), thyroid-stimulating immunoglobulin, anti-thyroid peroxidase antibody, and anti-thyroglobulin antibody (TgAb). Differential diagnosis accuracy was calculated using seven machine learning algorithms. In the initial blood test, Graves’ disease was characterized by increased thyroid hormone levels and subacute thyroiditis showing elevated inflammatory markers. The diagnostic accuracy of Model 1 was 65–70%, and Model 2 accuracy was 78–90%. The random forest model had the highest classification accuracy. The significant variables were CRP and T3 in Model 1 and TBII, CRP, and TgAb in Model 2. We suggest monitoring the initial T3 and CRP levels with subsequent confirmation of TBII and TgAb in the differential diagnosis of thyrotoxicosis.

Graves’ Ophthalmopathy in the Setting of Primary Hypothyroidism

Graves’ ophthalmopathy (GO) is commonly associated with hyperthyroidism secondary to Graves’ disease (GD). Although rare, there have been case reports of it occurring in patients who are hypothyroid with underlying Hashimoto’s thyroiditis (HT), as well as in euthyroid patients. Below, we describe a case of GO developing in a patient who has hypothyroidism secondary to HT successfully treated with high-dose steroids.

We present a case of a 53-year-old female known to have primary hypothyroidism (Hashimoto’s thyroiditis) diagnosed at the age of 39 years and has been on levothyroxine since diagnosis. She presented to our endocrine clinic complaining of new-onset diplopia and periorbital swelling for five months. There is no previous hyperthyroid state or radioactive iodine therapy. Examination showed left-sided upper and lower eyelid swelling, limited abduction with diplopia, and mild punctate keratopathy. Laboratory investigation revealed positive thyroid-stimulating immunoglobulin of 500 IU/mL (normal value: <140 IU/mL) with thyroid-stimulating hormone (TSH) and free thyroxine (FT4) in the euthyroid range. She was found to have a small heterogeneous thyroid gland on ultrasound suggestive of atrophic thyroiditis, and magnetic resonance imaging (MRI) of the orbits demonstrated bilateral ocular proptosis with extraocular muscle enlargement.

The patient was diagnosed with active moderate-severe isolated GO with a background of HT, clinically and biochemically euthyroid on levothyroxine. She was referred to an ophthalmologist and was started on a course of high-dose oral prednisone tapered over three months, which was followed by oral selenium and botox injections to both medial recti muscles.

Graves’ ophthalmopathy is an uncommon presentation in hypothyroid and euthyroid patients but should be considered in the differential diagnosis. The incidence varies between studies from 2% to 7.5%. Awareness of this clinical presentation is important, as early detection and treatment can prevent visual complications. To date, there are no clear guidelines on how to treat GO with underlying HT. Treating our patient with high-dose steroids extrapolated from treating GO secondary to GD showed significant improvement in her symptoms.

Elevated Graves' Disease-Specific Thyroid-Stimulating Immunoglobulin and Thyroid Stimulating Hormone Receptor Antibody in a Patient With Subacute Thyroiditis

Subacute thyroiditis can be rarely associated with autoimmune thyroid disorders. It includes Graves' disease which is characterized by the presence of a highly specific antibody known as thyroid-stimulating hormone (TSH) receptor antibody (TRAb). There are three types of TRAb: TSH receptor stimulating antibody (TSAb) which stimulates the TSH receptor causing Graves' disease, TSH receptor blocking antibody (TBAb) which blocks the TSH receptor causing hypothyroidism, and a neutralizing antibody which does not alter the thyroid function. There are two assays used to check the TRAb: the thyroid-stimulating immunoglobulin (TSI) assay and the TSH receptor-binding inhibitor immunoglobulin (TBII) assay out of which the TSI assay measures the stimulating antibody which is specific for graves' disease. Although autoimmune thyroid disorders can rarely occur following subacute thyroiditis, their clinical presentation is usually compatible with the type of antibody detected in the patient’s serum.

We present a unique case of a 44-year-old patient who presented with subacute thyroiditis followed by the development of persistent hypothyroidism even in the presence of elevated Graves' disease-specific TSI and TRAb.

A systematic review of euthyroid Graves' disease (Review)

Euthyroid Graves' Disease (EGD) is a challenging pathology, due to its atypical clinical manifestations and the absence of abnormal thyroid function. Typically, thyroid ophthalmopathy is associated with elevated thyroid hormone levels and with the presence of thyrotropin receptor antibodies (TRAb) but a low percentage of patients remain euthyroid without developing hyperthyroidism during long-term follow-up periods. Although it is considered a different pathology, it shares a lot of similarities with Graves' disease, rendering the diagnosis more difficult. It is also important to note that ophthalmopathy may be the first clinical manifestation of Graves' disease and that thyroid function examinations do not present abnormalities over a long period. Treatment choices for euthyroid disease do not differ from those described in Graves' ophthalmopathy. However, it is considered that since euthyroid patients develop milder ophthalmic symptoms and their clinical activity score is lower, they tend to have better responses to treatment. Moreover, atypical sight-threatening cases such as exposure keratopathy and dysthyroid optic neuropathy with variable responses to therapy also exist. Disease management consists of a favorable collaboration between ophthalmologists and endocrinologists because patients with EGD can develop thyroid abnormalities over time. In conclusion, the diagnosis of EGD is difficult, clinical manifestations and evolution are variables depending on several factors, including the heterogeneity of TRAb. This review aimed to identify the characteristics of this disease by reviewing the clinical studies and case reports published in previous years.

Programmed Cell Death-Ligand 1 (PD-L1) gene Single Nucleotide Polymorphism in Graves' Disease and Hashimoto's Thyroiditis in Korean Patients

BACKGROUND

Programmed cell death-ligand 1 (PD-L1) has an important role in regulating immune reactions by binding to programmed death 1 (PD-1) on immune cells, which could prevent the exacerbation of autoimmune thyroid disease (AITD). The aim of this study was to evaluate the association of PD-L1 polymorphism with AITD, including Graves' disease (GD) and Hashimoto's thyroiditis (HT).

METHODS

A total of 189 GD patients, 234 HT patients, and 846 healthy age- and sex-matched controls were enrolled in this study. We analyzed PD-L1 single nucleotide polymorphism (SNP) (rs822339) and investigated the associations with clinical disease course and outcome.

RESULTS

Genotype frequency at the PD-L1 marker RS822339 in GD (P=0.219) and HT (P=0.764) patients did not differ from that among healthy controls. In patients with GD, the A/G or G/G genotype group demonstrated higher TBII titer (20.6±20.5 vs. 28.0± 25.8, P=0.044) and longer treatment duration (39.0±40.4 months vs. 62.4±65.0 months, P=0.003) compared to the A/A genotype group. Among patients in whom anti-thyroid peroxidase (TPO) antibody was measured after treatment of GD, post-treatment antiTPO positivity was higher in the A/G or G/G genotype group compared to the A/A genotype group (48.1% vs. 69.9%, P=0.045). Among patients with HT, there was no significant difference of anti-TPO antibody positivity (79.4% vs. 68.6%, P=0.121), anti-thyroglobulin antibody positivity (80.9% vs. 84.7%, P=0.661), or development to overt hypothyroidism (68.0% vs. 71.1%, P=0.632) between the A/A genotype group and the A/G or G/G genotype group.

CONCLUSION

The genotype frequency of PD-L1 (rs822339) is not different in patients with AITD compared with healthy controls. The intact PD-1/PD-L1 pathway in GD and HT might be important to maintain chronicity of AITD by protecting immune tolerance. However, the PD-L1 SNP could be associated with difficulty in achieving remission in patients with GD, which may be helpful to predict the possibility of longer treatment. Further studies are required to investigate the complex immune tolerance system in patients with AITD.

PROGNOSIS OF DIFFERENTIATED THYROID CARCINOMA IN PATIENTS WITH GRAVES DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: It is still controversial whether differentiated thyroid carcinoma (DTC) in patients with Graves disease (GD) can be more aggressive than non-Graves DTC. We conducted a systematic review and meta-analysis to examine the association between GD and prognosis in patients with DTC. Methods: We comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2019. We included published studies that compared the risk of mortality and prognosis between DTC patients with GD and those with non-GD. Data from each study were combined using the random-effects model. Results: Twenty-five studies from February 1988 to May 2018 were included (987 DTC patients with GD and 2,064 non-Graves DTC patients). The DTC patients with GD had a significantly higher risk of associated multifocality/multicentricity (odds ratio, 1.45; 95% confidence interval, 1.04 to 2.02; I², 6.5%; P = .381) and distant metastasis at the time of cancer diagnosis (odds ratio, 2.19; 95% confidence interval, 1.08 to 4.47; I², 0.0%; P = .497), but this was not associated with DTC-related mortality and recurrence/persistence during follow-up. Conclusion: Our meta-analysis demonstrates a statistically significant increased risk of multifocality/multicentricity and distant metastasis at the time of cancer diagnosis in DTC patients with GD than those without GD. Abbreviations: CI = confidence interval; DTC = differentiated thyroid carcinoma; GD = Graves disease; LN = lymph node; OR = odds ratio; PTC = papillary thyroid carcinoma; TC = thyroid carcinoma; TSAb = thyroid-stimulating antibody; TSH = thyroid-stimulating hormone.

Rapid Changes of Thyroid Function in a Young Woman with Autoimmune Thyroid Disease

OBJECTIVE

A conversion from Hashimoto's thyroiditis to Graves' disease and vice versa leads to diagnostic and therapeutic challenges.

CLINICAL PRESENTATION AND INTERVENTION

A 30-year-old female presented with overt hyperthyroidism and negative thyroid-stimulating hormone receptor antibodies (TRAbs). Since hashitoxicosis was assumed, the patient was treated with propranolol. Within the next few weeks, the patient developed severe overt hypothyroidism, which was treated with levothyroxine. However, after several more weeks, she presented with overt hyperthyroidism once again, this time showing elevated TRAbs.

CONCLUSION

We suggest educating patients and physicians to recognize changes in thyroid function and close monitoring of unclear cases of overt hyperthyroidism.

Usefulness of TSH receptor antibodies as biomarkers for Graves' ophthalmopathy: a systematic review

PURPOSE

Over the past several decades, many papers have been published about the usefulness of thyrotropin receptor antibodies (TRAbs) as biomarkers of Graves' ophthalmopathy (GO). However, results have been inconsistent. The purpose of this analysis is to determine a possible cause of these discrepancies and to examine the usefulness of TRAbs as biomarkers for GO, especially 'thyrotropin-binding inhibiting immunoglobulin (TBII)' and 'thyroid-stimulating antibody (TSAb)'.

METHOD

26 articles discussing the association between TRAbs and GO were selected which were then divided into three groups based on the study method and whether or not the patients had been treated for hyperthyroidism. From the results of the papers reviewed, a provisional conclusion was made and a theoretical model on the TBII-TSAb coordinate plane was developed to confirm that conclusion.

RESULTS

TSAb is reported to be significantly or strongly associated with GO in the studies of pre- and post-treated patients for hyperthyroidism. TBII is positively correlated, negatively correlated or uncorrelated with GO in studies of pre-treated patients. However, it is generally agreed upon that TBII and GO are closely correlated in studies of post-treated patients.

CONCLUSION

We conclude that the level of TBII may not be a reliable indicator of the current state of GO in pre-treated patients. Whereas, in post-treated patients, due to changes in the correlation between TBII and TSAb due to the effect of hyperthyroidism treatment, the level of TBII can be a more reliable indicator of GO. Furthermore, the current level of TBII is closely associated with the onset and severity of GO in the future and it can be a valid predictor of GO. However, the TSAb level appears to be more reliable.

Socioeconomic Disparities in the Presentation and Treatment of Graves' Disease and Thyroid Eye Disease

Thyroid eye disease (TED) is an inflammatory, autoimmune orbitopathy with multifactorial etiology. Clinical presentation of TED spans a range from mild surface irritation to vision threatening compressive optic neuropathy. Potential vision loss underscores the importance of understanding genetic and environmental factors influencing the severity of TED presentation. This review will describe the classic risk factors for TED, outline treatments for Graves' disease (GD) and TED, and describe newer evidence of socioeconomic disparities in TED presentation.

The clinical use of thyroid function tests

Laboratory tests are essential for accurate diagnosis and cost-effective management of thyroid disorders. When the clinical suspicion is strong, hormonal levels just confirms the diagnosis. However, in most patients, symptoms are subtle and unspecific, so that only biochemical tests can detect the disorder. The objective of this article is to do a critical analysis of the appropriate use of the most important thyroid function tests, including serum concentrations of thyrotropin (TSH), thyroid hormones and antithyroid antibodies. Through a survey in the MedLine database, we discuss the major pitfalls and interferences related to daily use of these tests and recommendations are presented to optimize the use of these diagnostic tools in clinical practice.

Negative correlation between bone mineral density and TSH receptor antibodies in long-term euthyroid postmenopausal women with treated Graves' disease

BACKGROUND

Thyrotoxicosis is a cause of secondary osteoporosis. High concentrations of triiodotironine (T3) in Graves' disease stimulate bone turnover, but it is unclear if euthyroidism will always normalize bone metabolism. Thyrotropin (TSH) is known to affect directly the bone metabolism through the TSH receptor and TSH receptor antibodies (TRAb) may have an important role in bone turn-over.The aim of our study was to determine, in pre and postmenopausal euthyroidism patients with previous overt hyperthyroidism due to Graves' disease the bone mineral density (BMD) as well as factors that could affect BMD in each group, including TRAb.

METHODS

Cross-sectional, non-interventional study. Fifty-seven patients with previous hyperthyroidism due to Graves' disease (premenopausal: 30, postmenopausal: 27) that remained euthyroid for at least 6 months prior to study were included and compared with fifty- two matched respective controls. Thyrotoxine (T4), TSH, TRAb and BMD were measured.

RESULTS

Only euthyroid postmenopausal patients with a history of hyperthyroidism due to Graves' disease showed lower whole body BMD than matched controls. The BMD expressed as Z-score was less in whole body and lumbar spine in postmenopausal in relation to premenopausal women with previous overt hyperthyroidism due to Graves' disease.In the postmenopausal patients, the Z-score of lumbar spine BMD correlated negatively with TRAb (r = -0,53, p < 0.008), positively with the time of evolution of the disease (r = +0.42, p < 0.032) and positively with the time of euthyroidism (r = + 0.50, p < 0.008), but neither with serum T4 nor TSH. In a multiple regression analysis TRAb was the only significant independent variable in relation to lumbar spine BMD (F = 3. 90, p < 0.01).

CONCLUSIONS

In euthyroid women with a history of Graves' hyperthyroidism, BMD was only affected in the postmenopausal group. The negative correlation of Z-score of lumbar spine BMD with TRAb suggests that this antibody may affect the bone metabolism.

Changes of TSH-Stimulation Blocking Antibody (TSBAb) and Thyroid Stimulating Antibody (TSAb) Over 10 Years in 34 TSBAb-Positive Patients with Hypothyroidism and in 98 TSAb-Positive Graves' Patients with Hyperthyroidism: Reevaluation of TSBAb and TSAb in TSH-Receptor-Antibody (TRAb)-Positive Patients

TWO TRABS: TSBAb and TSAb. TSBAb causes hypothyroidism. TSAb causes Graves' hyperthyroidism. TSBAb and TSAb block TSH-binding to cells as TRAb, measured as TSH-binding inhibitory immunoglobulin (TBII). We reevaluate TSBAb and TSAb. We studied TSBAb, TSAb, and TBII over 10 years in 34 TSBAb-positives with hypothyroidism and in 98 TSAb-positives with hyperthyroidism. Half of the 34 TSBAb-positives with hypothyroidism continued to have persistently positive TSBAb, continued to have hypothyroidism, and did not recover from hypothyroidism. Ten of the 98 TSAb-positives with hyperthyroidism continued to have positive TSAb and continued to have hyperthyroidism. TSBAb had disappeared in 15 of the 34 TSBAb-positives with hypothyroidism. With the disappearance of TSBAb, recovery from hypothyroidism was noted in 13 (87%) of the 15 patients. TSAb had disappeared in 73 of the 98 TSAb-positives with hyperthyroidism. With the disappearance of TSAb, remissions of hyperthyroidism were noted in 60 (82%) of the 73. Two of the 34 TSBAb-positives with hypothyroidism developed TSAb-positive Graves' hyperthyroidism. Two of the 98 TSAb-positive Graves' patients with hyperthyroidism developed TSBAb-positive hypothyroidism. TSBAb and TSAb are TRAbs. TSBAb-hypothyroidism and TSAb-hyperthyroidism may be two aspects of one disease (TRAb disease). Two forms of autoimmune thyroiditis: atrophic and goitrous. We followed 34 TSBAb-positive patients with hypothyroidism (24 atrophic and 10 goitrous) over 10 years. All of the 10 TSBAb-positive goitrous patients recovered from hypothyroidism and 19 (79%) of the 24 TSBAb-positive atrophic patients continued to have hypothyroidism.

Structured exercise program improves functional capacity and delays relapse in euthyroid patients with Graves' disease

PURPOSE

To evaluate short- and long-term effects of structured exercise program in euthyroid patients with Graves' disease.

METHODS

The study employed a retrospective case-control design. The exercise group (n = 62) underwent 3 weeks of structured exercise program consisting of daily walking, strengthening, and stretching exercises while the control group (n = 62) participated in leisure activities. Thyroid profile, aerobic capacity, and perceived fatigue were evaluated on in-patient admission and discharge. Time to discontinuation of anti-thyroid medication after discharge and time to relapse of symptoms were determined.

RESULTS

The exercise group increased estimated peak oxygen consumption (significant group-by-time ANOVA interaction, P < 0.001), decreased serum thyroxin (P = 0.038), increased serum thyrotropin (P = 0.071), and reported less fatigue (Fisher's exact test, p < 0.001) from admission to discharge. The anti-thyroid medication was withdrawn within 6 months of discharge in significantly greater proportion of subjects in the exercise than control group (84% vs. 18%). Conversely, the rate of relapse within 12 months of medication withdrawal was smaller in the exercise (29%) than control group (72%).

CONCLUSIONS

The results suggest that structured exercise program may normalize thyroid profile, improve aerobic capacity, and reduce fatigue on the short-term basis as well as reduce the need for anti-thyroid medication on the long-term basis.

Rituximab for thyroid eye disease

PURPOSE

To assess the efficacy and safety of rituximab-mediated B-lymphocyte depletion as treatment for thyroid eye disease (TED).

METHODS

Prospective, open-label, interventional clinical trial evaluating 12 patients with TED and Clinical Activity Scores (CAS) (VISA [vision, inflammation, strabismus and appearance/exposure] classification) of 4 or greater followed for 1 year after rituximab (1000 mg) treatment, administered intravenously on days 1 and 15. CAS, peripheral B-lymphocyte levels, thyroid autoantibody levels, and thyroid function tests were recorded at baseline, 4 weeks, 8 weeks, 12 weeks, 24 weeks, 36 weeks, and 52 weeks after the second infusion. The primary endpoint was a change from baseline in CAS. Thyroid-stimulating immunoglobulin and thyroid-stimulating hormone levels were also monitored over the 12-month postinfusion observation period.

RESULTS

CAS scores demonstrated a statistically significant decrease from baseline at each of the follow-up visits. Thyroid-stimulating immunoglobulin and thyroid-stimulating hormone levels demonstrated no statistically significant change from baseline. B-cell depletion was observed within 1 month after rituximab treatment, and peripheral B-lymphocyte counts started to increase 36 weeks after the infusion. B-cell depletion was well tolerated, and there were no adverse effects of the rituximab infusions.

CONCLUSIONS

CAS scores were significantly reduced over time in this group of 12 patients and appeared to be associated with rituximab infusion. The variable natural history of TED makes it difficult to definitively assign efficacy. The results support the continued investigation of rituximab for TED in a larger placebo-controlled trial.

Hashimoto's thyroiditis: TGAb, TPOAb, TRAb and recovery from hypothyroidism

Hashimoto described four patients with goiter. The histology of the goiter was characterized by diffuse lymphocytic infiltration, fibrosis and epithelial cell destruction. Thyroglobulin antibody (TGAb) and thyroid peroxidase antibody (TPOAb) have been used to diagnose Hashimoto's thyroiditis. Patients with positive TGAb and/or TPOAb have been assumed to have Hashimoto's thyroiditis. Approximately 10% of those with positive TGAb and/or TPOAb have hypothyroidism. There are two types of autoimmune thyroiditis: goitrous Hashimoto's thyroiditis and atrophic thyroiditis. The latter patients have blocking antibody (thyroid-stimulating hormone [TSH]-stimulation blocking antibody [TSBAb]). TSBAb is a TSH-receptor antibody (TRAb). TSBAb causes thyroid atrophy and hypothyroidism. TGAb and/or TPOAb do not necessarily cause hypothyroidism. Hypothyroid patients with Hashimoto's thyroiditis usually receive life-long l-thyroxine therapy. However, spontaneous recovery from hypothyroidism has been reported. Patients who had Hashimoto's hypothyroidism and then Graves' hyperthyroidism (and vice versa), have also been reported. Hashimoto's hypothyroidism and Graves' hyperthyroidism could be the opposite spectrums of one disease.

Clinical review about TRAb assay's history

Commercial assays to measure thyroid stimulating hormone (TSH) receptor (TSHR) autoantibodies (TRAb) have been available for the serological diagnosis of autoimmune thyroid diseases (AITD) for several years. The widespread assessment of this parameter has identified Graves' disease (GD) as a common organ-specific autoimmune disease. Within the present article we aim to review immunobiological and epidemiological aspects as well as diagnostic methods available for the detection of TRAb. Over the last decade, TRAb detection in GD became more sensitive since TRAb assays were being largely improved by named research groups. Therefore, functional assay (fas) and diagnostic sensitivity of current TRAb assays will be discussed. Within the second part of this review we will focus on clinical applications of TRAb measurement for outcome prediction of GD as well as the importance of this method to distinguish GD from other AITD.

Treatment of pretibial myxedema (PTM) with topical steroid ointment application with sealing cover (steroid occlusive dressing technique: steroid ODT) in Graves' patients

Localized pretibial myxedema (PTM) is a sign of Graves' disease. A 53-year-old man with Graves' disease was admitted with the development of PTM following radioisotope (131)I treatment for Graves' hyperthyroidism. TSH receptor antibody (TRAb) titer was also increased after (131)I treatment. TRAb was measured as thyroid stimulating antibody (TSAb) or TSH-binding inhibitory immunoglobulin (TBII). PTM was noted several months after (131)I treatment. The PTM-development seems to be associated with the increased TRAb-activities. The localized pretibial myxedema was effectively treated with topical steroid (triamcinolone acetonide) ointment application with sealing cover (steroid occlusive dressing technique: steroid ODT). We also report our experience of PTM-treatment with steroid ODT in 5 other PTM patients with positive TRAb. PTM was successfully treated with steroid ODT in two patients. In these two patients, the treatment was started within several months of the appearance of PTM. In the other 4 patients, the treatment was started 5-10 years after the appearance of PTM without any beneficial effects. Early detection and early treatment are necessary for the remission of PTM.

Thyroid stimulating immunoglobulin is often negative in children with Graves' disease

BACKGROUND

The diagnosis of Graves' disease (GD) is typically confirmed with a thyroid stimulating immunoglobulin (TSI) titer. While TSI is reported to be positive in >90% of patients with GD, our anecdotal experience suggests that TSI negative GD may be more common in children.

AIM

To investigate the incidence of TSI negative GD in our population and to compare patients with TSI negative vs TSI positive GD.

METHODS

Charts of children with GD seen in our pediatric endocrinology clinic over the past 5 years were reviewed.

RESULTS

Fifty-seven patients with GD were included. TSI was negative in 43% of patients. No significant differences were found in children with TSI negative vs TSI positive GD.

CONCLUSIONS

In patients with GD, the finding of a negative TSI titer usually creates diagnostic uncertainty. However, the fact that nearly half of our patients with GD were TSI negative suggests that this is common in children.

Association of an A/C single nucleotide polymorphism in programmed cell death-ligand 1 gene with Graves' disease in Japanese patients

OBJECTIVE

Programmed cell death-1 (PD-1) and its ligands (PD-L1 and PD-L2) inhibit T-cell proliferation and activation. This inhibition down-regulates the immune responses. The association of a PD-L1 polymorphism with Graves' disease (GD) was studied.

DESIGN

The association of an A/C polymorphism at position 8923 in PD-L1 intron 4 with GD was studied.

PATIENTS

The study included 327 GD patients and 192 controls, of which 252 GD patients were followed over 5-10 years.

MEASUREMENTS

PD-L1 intron 4 position 8923 A/C polymorphism was typed using the PCR-restriction fragment length polymorphism method.

RESULTS

The A/C genotype frequencies were significantly different between GD patients and controls. The A/C and C/C frequencies were higher in GD patients than in controls. The A/A frequencies were lower in GD patients than in controls. C-allele frequency was higher in GD patients than in controls. A total of 252 GD patients were followed over 5-10 years; 200 had discontinued antithyroid drugs (ATD) while 52 continued to take ATD. Of these 200, 176 continued to be in remission and 24 had relapsed into hyperthyroidism. Significant differences in the duration of positive TBII, positive thyroid-stimulating antibodies, and ATD treatment were noted between the patients in remission and those that had relapsed. Significant differences in the A- and C-allele frequencies were noted between the two. The C-allele frequency was higher in GD patients who did not achieve remission than in those who achieved remission.

CONCLUSION

An A/C polymorphism at position 8923 in PD-L1 is associated with GD. The PD-L1 polymorphism plays a role in GD development. GD patients with the C allele at position 8923 in PD-L1 gene had difficulty in achieving remission.

HLA class II distribution in Congolese with hyperthyroidism: preliminary results

OBJECTIVE

Incidence of the hyperthyroidism is continuously increasing, whereas our knowledge concerning the facilitating or etiologic factors of this increase are still partial. To evaluate some of these unknown factors, we started this preliminary study, in order to identify HLA genes in hyperthyroid Congolese, and to determine their susceptibilty in the appearance and development of hyperthyroidism at the Hospital Clinic of Kinshasa.

MATERIALS AND METHODS

Nine Congolese women with hyperthyroidism, and thirteen healthy controls (3 women and 10 men) were examined and compared for HLA-DR and HLA-DQ genes analyses, from August 2000 to August 2002. DRB1 and DQB1 alleles were identified, using the Polymerase Chain Reaction (PCR) and immobilized sequence-specific oligonucleotide (SSO HLA-DRB1 and DQB1 test) probes assays.

RESULTS

In the group with hyperthyroidism, three alleles (HLA-DR1, HLA-DR2, HLA-DR3) and an allele group (HLA-DR11,13,14) were found for DRB1 locus, while only one allele (HLA-DQB1*0602) was identified for DQB1 locus; allele group HLA-DR11,13,14 was the most frequent (allele frequency=0.50), followed by HLA-DR3 allele (allele frequency=0.222); 6 haplotypes were observed, with predominance of haplotype DR3/DR11,13,14 (genotype frequency=0.333), followed by haplotype DR11,13,14/DR11,13,14-DQB1*0602 (genotype frequency=0.222). In the group of healthy controls, three alleles (HLA-DR2, HLA-DR3, HLA-DR4) and an allele group (HLA-DR11,13,14) were identified for DRB1; HLA-DR2 allele was predominant (allele frequency=0.615), followed by allele group HLA-DR11,13,14 (allele frequency=0.231); a statistic significant difference was observed between the frequencies of DR2 allele and allele group DR11,13,14 in the healthy controls compared to those of hyperthyroid patients (p=0.02); 6 haplotypes were also detected in this group, the most frequent haplotype being HLA-DR2/DR2-DQB1*0602 (genotype frequency=0.540 versus 0.333 in the hyperthyroid group) (p=0.048). HLA-DQB1*0602 was dominant in the healthy controls group (allele frequency=0.890), versus HLA-DQB1*0302 (allele frequency=0.110).

CONCLUSIONS

HLA-DR2, HLA-DQB1*0602 and DR2/DR2-DQB1*0.602 would play a protective role against the hyperthyroidism, while DR3 allele, allele group DR11,13,14 and haplotype HLA-DR3/DR11,13,14 would predispose to this disease or to Graves' exophtalmopathy. A large and profound study is needed to confirm our preliminary results.

Continued suppression of serum TSH level may be attributed to TSH receptor antibody activity as well as the severity of thyrotoxicosis and the time to recovery of thyroid hormone in treated euthyroid Graves' patients

The cause of continued suppression of serum thyroid-stimulating hormone (TSH) levels during antithyroid drug therapy in some Graves' patients is unclear. Recently, there has been a notable explanation involving the direct inhibition of TSH receptor antibody (TRAb) on TSH secretion in the pituitary gland. The purpose of this study is to verify the relation between TRAb or other clinical parameters and the continued suppression of serum TSH level during antithyroid drug therapy in patients with Graves' disease. We reviewed the medical records of patients with Graves' disease between 1995 and 2002 at Samsung Medical Center. We selected 167 Graves' patients who had been euthyroid for at least 12 months after recovery of serum T3 and T4 levels during the antithyroid drug therapy. We analyzed the correlation of the interval until recovery of serum TSH with the pretreatment clinical parameters. We compared the recovery rates of suppressed TSH levels between pretreatment thyrotrophin-binding inhibitory immunoglobulin (TBII)-positive (>15%) and TBII-negative patients. We also compared the clinical parameters between two groups at the time of diagnosis and after recovery of thyroid hormone. Pretreatment serum T3 level, (131)I uptake, TBII activity, and the time to recovery of T3 or T4/free T4 level showed significant positive correlations with the interval until recovery of serum TSH level ( p < 0.05). Recovery rates of serum TSH levels at 3 months after recovery of thyroid hormone were significantly lower in pretreatment TBII-positive patients than those in TBII-negative patients ( p < 0.01). Serum TSH levels were significantly lower in TBII-positive patients at 3 months after recovery of thyroid hormone ( p < 0.05). TBII activities inversely correlated only with serum TSH levels at 3months after recovery of thyroid hormone ( p < 0.001). In conclusion, continued suppression of serum TSH level may be attributed to TRAb activity as well as the pretreatment severity of thyrotoxicosis and the time to recovery of thyroid hormone in patients with Graves' disease during antithyroid drug therapy.

TSH-Dependent expression of the LDL receptor-associated protein (RAP) in thyroid epithelial cells

The low density lipoprotein (LDL) receptor-associated protein (RAP) is an endoplasmic reticulum (ER)-resident molecular chaperone for several LDL receptor family members and it also binds to thyroglobulin (Tg), the thyroid hormone precursor. Disruption of the RAP gene in thyrocytes results in impaired Tg secretion. To gain further insights into the function of RAP in the thyroid, we investigated whether its expression in thyrocytes is regulated by thyroid-stimulating hormone (TSH), a feature common to all proteins involved in thyroid hormone secretion. We found by immunofluorescence that in FRTL-5 cells cultured in the presence of TSH, RAP is expressed intracellularly. The levels of expression increased after exposure to TSH, beginning at 48 hours, in a concentration-dependent manner as observed by immunofluorescence and Western blotting. Expression of RAP was also increased by TSH in primary cultures of human thyrocytes as observed by Western blotting. In hypothyroid mice with high serum TSH, RAP was markedly increased compared with euthyroid mice as observed by immunohistochemistry and Western blotting. Based on these findings, we concluded that RAP is expressed by thyrocytes in a TSH-dependent manner, both in cultured thyroid cells and in vivo.

Evaluation of management of Graves' disease in District General Hospital: achievement of consensus guidelines

The management of Graves' disease in a District General Hospital was audited. A local care pathway was designed, which was inclusive of diagnosis, treatment and follow-up. This was then compared with consensus guidelines proposed by the Royal College of Physicians. Forty-six patients with Graves' disease attended the endocrine clinic. The diagnosis was based on clinical and biochemical features of autoimmune thyrotoxicosis, a raised thyroid-stimulating hormone receptor antibody (TRAB) and a diffusely increased uptake in thyroid technetium scan. They were treated for 18 months with antithyroid medications, which was subsequently discontinued provided satisfactory euthyroid state was achieved. Patients were followed up to assess remission and relapse status. The audit suggested that care pathway was in keeping with the guidelines. A few excess TRAB tests were requested. The relapse rate was 42% in our series and one-third of them (33%) chose to continue medical therapy.

Juvenile thyrotoxicosis; can we do better?

Thyrotoxicosis remains a frustrating condition for the young person, family, and health professionals involved. The associated symptoms do not always suggest thyroid disease and patients can be unwell for many months before the diagnosis is made. The antithyroid drug regimen used to treat children and adolescents with thyrotoxicosis varies from one unit to another and yet the potentially life threatening side effects and remission rates post-treatment may be related to the regimen used. Most patients with thyrotoxicosis will need many years of drug therapy if the thyroid gland is not removed surgically or destroyed by radioiodine. Even "definitive" treatment will typically necessitate thyroxine replacement for life.

Thyroid autoantibodies

Although assays to detect thyroid autoantibodies have been available for more than 40 years, their place in the clinical management of thyroid disease has remained controversial; however, novel automated detection techniques using recombinant antigens are increasing the sensitivity and specificity of the assays, particularly for antibodies to the TSH receptor. In addition, new antigenic targets have been defined including the sodium-iodide symporter and four eye muscle proteins targeted in Graves' ophthalmopathy. This article summarizes the immunobiology, assay methodology and prevalence in thyroid diseases of each of the major thyroid autoantibodies before discussing the clinical indications for their use in thyroid diseases.

Prevalence of thyroid peroxidase, thyroglobulin and thyrotropin receptor antibodies in a long-term follow-up of juvenile Graves disease

OBJECTIVE

To relate the presence of thyroid peroxidase antibodies (TPO ab), thyroglobulin antibodies (Tg ab) and thyrotropin receptor antibodies (TSH-R ab) to the clinical course in a long-term follow-up of patients with juvenile Graves' disease (JGD).

DESIGN

Patients with JGD were drawn from a Danish retrospective study and reexamined.

RESULTS

A number of 105 patients were reexamined 4-21 years (median 10 years) after diagnosis. Three groups were formed: Gr.1: euthyroid patients with anti-thyroid drug (ATD) cessation more than 12 months before reexamination (n=41). Gr.2: patients still on ATD (n=24). Gr.3: subtotally thyroidectomized patients (n=40). Positive TPO ab titers were found in 75% of the patients. In 13% of the patients the titers were very high: >10,000 U/ml. Positive Tg ab were found in 51%. The prevalence of TPO ab and Tg ab was the lowest in group 3. Stimulating TSH-R ab titers were found in 13%. No patients had blocking TSH-R ab. The prevalence of TSH-R ab was 3% in the euthyroid patients, without surgery performed. 15% in the surgical patients, and 25% in the patients still on ATD.

CONCLUSIONS

Many JGD patients were euthyroid at the long-term follow-up in spite of high TPO ab and Tg ab titers. Stimulating TSH-R ab were rare (13%). According to this presence of TPO ab, Tg ab or TSH-R ab does not predict the final outcome of JGD. Further studies are needed.

Remission of Graves' hyperthyroidism predicted by smooth decreases of thyroid-stimulating antibody and thyrotropin-binding inhibitor immunoglobulin during antithyroid drug treatment

It is important to know whether a patient with Graves' disease will get into remission or not during antithyroid drug (ATD) treatment. Thyrotropin (TSH) receptor antibodies (TRAb) cause Graves' disease. Thyroid-stimulating antibody (TSAb) and TSH-binding inhibitor immunoglobulin (TBII) have been measured as TRAb to diagnose Graves' disease and to follow Graves' patients. Smooth decreases of TSAb and TBII during ATD treatment predict the remission of Graves' hyperthyroidism. We followed serial changes of TSAb and TBII in 58 Graves' patients before, during, and after ATD treatment; TSAb was measured as a stimulator assay, using porcine thyroid cells, and TBII as a receptor assay. Patterns of TSAb and TBII changes during ATD treatment differ from one patient to another. TSAb and TBII activities decreased and disappeared in 52 (group A) but continued to be high in the other 6 (group B); 39 of the 52 group A patients achieved remission, but all of the 6 group B patients with persistently positive TSAb and TBII continued to have hyperthyroidism. No differences in the initial TSAb and TBII activities were noted between the 52 group A patients and the 6 group B patients. Of the 52 group A patients in whom TSAb and TBII had disappeared, 44 had smooth decreases of TSAb and TBII (group A1), and 8 had complex changes of TSAb and/or TBII (group A2); 36 of the 44 group A1 patients (82%) but only 3 of the 8 group A2 patients (37%) continued to be in remission more than 1 year after ATD discontinuation. The number of remission in group A1 was significantly larger than that in group A2. No differences in the initial TSAb and TBII activities were noted between group A1 and group A2. More than 80% of group A1 patients, who had smooth decreases of TSAb and TBII, continued to be in remission longer than 1 year. We demonstrated that smooth decreases of TSAb and TBII during ATD treatment predicted the remission of Graves' hyperthyroidism. The Graves' patients can be classified into A1, A2, and B groups according to the patterns of TSAb and TBII changes during ATD treatment. Group A1 patients, who had smooth decreases of TSAb and TBII, had higher rate of remission than the others. Smooth decreases of TSAb and TBII during the early phase of ATD treatment are a reliable predictor of the remission.

Differences between changes in serum thyrotropin-binding inhibitory antibodies and thyroid-stimulating antibodies in the course of antithyroid drug therapy for Graves' disease

There has recently been controversy regarding whether the measurement of thyrotropin-binding inhibitory antibodies (TBIAb) is useful in the management of Graves' disease. Another method of assessing Graves' disease by measuring adenylate cyclase activity in thyroid cells, known as thyroid-stimulating antibodies (TSAb), differs from TBIAb not only in terms of assay but also in immunoglobulin type according to recent studies. In this study, the concentrations of TBIAb and TSAb were compared in serial serum samples collected from 29 patients with Graves' hyperthyroidism during 12 months of antithyroid drug therapy. Before therapy, there was a correlation between TBIAb and TSAb (r = 0.59). The radioactive iodine uptake (RAIU) was not significantly correlated with either TBIAb or TSAb (r = 0.20 and r = 0.29, respectively), and the serum free thyroxine (FT4) concentration was also not significantly correlated with either TBIAb or TSAb (r = 0.06 and r = 0.22, respectively). In patients with Graves' ophthalmopathy, TSAb levels were higher than in patients without ophthalmopathy (1015%+/-851% vs. 456%+/-323%, p<0.01), but the TBIAb levels were not significantly different. After antithyroid treatment, TBIAb did not decrease significantly (from 42.1%+/-20.8% to 20.5%+/-19.5%, p = 0.29). On the other hand, TSAb was significantly decreased after 12 months of treatment (from 649%+/-611% to 294%+/-205%, p< 0.05). These findings indicate that TBIAb and TSAb are not identical, and that TSAb has a closer relationship to thyroid function than TBIAb. In the clinical setting, determination of the serum TSAb level may provide a more accurate index of the thyroid status in Graves' disease patients receiving antithyroid therapy.

Factors at onset predictive of lasting remission in pediatric patients with Graves' disease followed for at least three years

Seventeen pediatric patients (mean age at diagnosis 10 yr and 9 mo +/- 2 yr and 9 mo) with Graves' disease treated with 0.3-0.7 mg/kg/day methimazole and followed for at least three years, during which drug suspension was attempted on attainment of good clinical and metabolic compensation, were retrospectively studied to look for factors predictive of lasting remission present at onset. Lasting remission was defined as a clinical and laboratory picture of euthyroidism lasting at least one year in the absence of treatment at the end of the follow-up. A distinction was drawn between patients who reached remission after one or two courses (groups 1 and 2) and those who never attained a lasting remission (group 3). TRAb (TBIAb) levels at onset were the only factor significantly correlated with the response to treatment. Age at diagnosis, goiter size and fT3 and fT4 concentrations were not significantly correlated with the clinical picture. The series was too small to allow any assessment of the real importance of these factors, though a generally better response was displayed by children over 11 years old, without appreciable or with very small goiter and moderately increased thyroid hormone levels at onset (fT3 < 25 pg/ml in 10/10 in groups 1 and 2 and 2/7 in group 3 patients; fT4 < 40 pg/ml in 7/10 in groups 1 and 2 and 3/7 in group 3 patients). It was also found that better results were obtained when the initial drug course was protracted for at least two years.

Augmentation of thyroid-stimulating antibody-stimulated cyclic adenosine monophosphate response by polyethylene glycol, polyvinyl alcohol, and dextran; highly sensitive porcine thyroid cell thyroid-stimulating antibody assay

Previously, we reported that 5% polyethylene glycol (PEG) (6000) augmented thyroid-stimulating antibody (TSAb)-stimulated cyclic adenosine monophosphate (cAMP) production in porcine thyroid cell (PTC) assay. This augmentation by PEG was specific to TSAb-stimulation. In this study we examined the effects of nonionic hydrophilic polymers such as PEG, polyvinyl alcohol (PVA), and dextran (DEX) on TSAb-stimulated cAMP production. We demonstrated that graded doses of PEG, PVA, and DEX augmented TSAb-stimulated cAMP productions; the prominent augmentations were observed with 5% PEG (20,000), 5% PEG (6000), 6% PEG (4000), 10% PVA, 14% DEX T-250, and 14% DEX T-70. PVA did not augment thyrotropin (TSH)-stimulated cAMP synthesis. Five percent PEG (20,000), 14% DEX T-250, and 14% DEX T-70 augmented TSH-stimulated cAMP synthesis very slightly. PEG, PVA, and DEX had no effects on the cAMP synthesis stimulated by GTPgammaS, forskolin, or pituitary adenylate cyclase activating polypeptide (PACAP), which stimulated adenylate cyclase. We also demonstrated that PEG, PVA, and DEX augmented the cAMP responses stimulated by small amounts (50 microL) of sera from Graves' patients; small amounts (50 microL) of sera could be used instead of purified immunoglobulin G (IgG). This may simplify the TSAb assay. We developed a highly sensitive simplified TSAb assay. PEG weakly augmented TSAb binding to isolated TSH receptor (thyrotropin-binding inhibitor immunoglobulin [TBII] increased slightly). The mechanisms of the augmentations of TSAb-stimulated cAMP productions by PEG, PVA, and DEX is not simply explained by increased binding of TSAb to the receptors. Some factors that enhance TSAb action at the receptor site are suggested.

Development of Graves' hyperthyroidism from primary hypothyroidism in a case of thyroid hemiagenesis

We report a 42-year-old female with right thyroid hemiagenesis who initially presented with hypothyroidism and then developed hyperthyroidism. The serum titer of thyroid-stimulating antibody was weakly positive in the initial hypothyroid state, and then markedly increased along with the development of hyperthyroidism, while thyroid stimulation-blocking antibody was continuously negative throughout the observation period. Thyroid histology of biopsied specimens during the hypothyroid state demonstrated diffuse thyroiditis with mononuclear cell infiltrations; however, the histology during the hyperthyroid state showed hyperplasia in follicular epithelial cells accompanied by partial lymphocyte infiltration. This is the first case of thyroid hemiagenesis associated with a conversion from primary hypothyroidism due to Hashimoto's thyroiditis to hyperthyroidism due to Graves' disease.