Clinical relevance of thyroid-stimulating autoantibodies in pediatric graves' disease-a multicenter study

Stimulating thyrotropin receptor antibodies in early pregnancy

OBJECTIVES

Thyrotropin-receptor antibodies (TRAb) are used to diagnose Graves' hyperthyroidism in pregnant women. Bioassays provide a measure of thyrotropin-receptor stimulatory antibodies (TSI) specifically. The objective was to measure TSI in pregnant women for establishment of a pregnancy-specific cut-off and comparison with immunoassay measurements of TRAb.

METHODS

The retrospective Danish study was performed within the North Denmark Region Pregnancy Cohort (2011-2015) that includes stored biobank samples from early pregnancy (median week 10) with immunoassay measurements of thyroid function parameters and TRAb. TSI were measured in the same samples using the Turbo TSI bioassay (Quidel/Ortho-Clinical Diagnostics) with a recommended cut-off of 0.0241 IU/L in non-pregnant adults. A pregnancy-specific TSI cut-off (95-percentile) was established using Regression on Order Statistics.

RESULTS

The established TSI cut-off was 0.0418 IU/L (95 % CI: 0.0417-0.0419). Among women with early pregnancy hyperthyroidism (n=438), 43 women (9.8 %) were TSI positive using the established cut-off, and these women had lower TSH (median 0.008 mIU/L) compared to women with TSI levels below 0.0241 (median TSH 0.040 mIU/L) or in the range from 0.0241 to 0.0418 (median TSH 0.033 mIU/L). Among the 438 women with early pregnancy hyperthyroidism, 22 women were positive for TSI and TRAb, 388 were negative for both, and 28 women were positive for either TSI or TRAb.

CONCLUSIONS

This is the first study on TSI measurements in a large cohort of early pregnant women. A pregnancy-specific cut-off for TSI was established and agreement in the classification with immunoassay measurements of TRAb was seen in 94 % of cases.

Molecular Biomarkers in Thyroid Eye Disease: A Literature Review

PURPOSE

Thyroid eye disease (TED) is the most common extrathyroidal manifestation of Graves disease. Patients may be severely affected with eyelid retraction, exophthalmos, diplopia, pain, and threatened vision. Autoantibodies against thyroid-stimulating hormone receptor and insulin-like growth factor 1 receptor have shown associations with pathophysiological and clinical traits. Autoantibodies against thyroid-stimulating hormone receptor is in current clinical use as biomarker, but not with unambiguous diagnostic performance. A biomarker with high diagnostic accuracy and/or prognostic capability would be of immense value in diagnosing TED, especially in subclinical cases or when TED precedes the thyroid dysfunction. This article is a literature review on molecular biomarkers of TED.

METHODS

A literature search was performed using PubMed and Embase. Studies on molecular biomarkers in blood, tear fluid, and urine were included in the review.

RESULTS

Forty-six papers were included, of which 30, 14, and 2 studies on biomarkers in blood, tears, and urine, respectively. Fourteen of the papers evaluated the diagnostic performance of various biomarkers, 12 in blood and 2 in tears. Most studies evaluated single biomarkers, but 3 tested a panel of several markers. Except for autoantibodies against thyroid-stimulating hormone receptor, the reported diagnostic performances for the biomarkers were not confirmed in independent cohorts. In 32 studies, no or insufficient performance data were given, but the findings indicated involvement of various biologic mechanisms in TED including inflammation, oxidative stress, fibrosis, lipid metabolism, and ocular surface microflora.

CONCLUSIONS

Currently, serum autoantibodies against thyroid-stimulating hormone receptor is the only molecular biomarker with clinical utility in patients with TED. Several potential biomarkers have been investigated, and particularly panels of multiple biomarkers in tears are promising. To improve patient care, biomarkers in TED should be studied further.

Dysthyroid Optic Neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) is a sight-threatening complication of thyroid eye disease (TED). This review provides an overview of the epidemiology, pathogenesis, diagnosis, and current therapeutic options for DON.

METHODS

A literature review.

RESULTS

DON occurs in about 5% to 8% of TED patients. Compression of the optic nerve at the apex is the most widely accepted pathogenic mechanism. Excessive stretching of the nerve might play a role in a minority of cases. Increasing age, male gender, smoking, and diabetes mellitus have been identified as risk factors. Diagnosis of DON is based on a combination of ≥2 clinical findings, including decreased visual acuity, decreased color vision, relative afferent pupillary defect, visual field defects, or optic disc edema. Orbital imaging supports the diagnosis by confirming apical crowding or optic nerve stretching. DON should be promptly treated with high-dose intravenous glucocorticoids. Decompression surgery should be performed, but the response is incomplete. Radiotherapy might play a role in the prevention of DON development and may delay or avoid the need for surgery. The advent of new biologic-targeted agents provides an exciting new array of therapeutic options, though more research is needed to clarify the role of these medications in the management of DON.

CONCLUSIONS

Even with appropriate management, DON can result in irreversible loss of visual function. Prompt diagnosis and management are pivotal and require a multidisciplinary approach. Methylprednisolone infusions still represent first-line therapy, and surgical decompression is performed in cases of treatment failure. Biologics may play a role in the future.

A NOVEL MONOCLONAL ANTIBODY DEGRADES THE THYROTROPIN RECEPTOR AUTOANTIBODIES IN GRAVES' DISEASE

OBJECTIVE

Autoantibodies (Ab) against the thyrotropin receptor (TSH-R-Ab) are key mediators for the pathogenesis of Graves' disease (GD). TSH-R-Ab degradation was evaluated using several immunoassays within an exploratory, controlled trial in patients with GD receiving a monoclonal antibody (mAb) targeting the neonatal crystallizable fragment receptor (FcRn).

METHODS

Serial measurements of TSH-R-Ab serum levels were performed using three different binding and cell-based assays in GD patients either on medication or on placebo.

RESULTS

In contrast to placebo where no changes were observed, a 12-week mAb therapy led to an early and significant decrease (> 60%) of the serum TSH-R-Ab serum levels in patients with thyroidal and extra-thyroidal GD, as unanimously shown in all three assays. These marked changes were noted already at week seven post baseline (P<0.0001 for the binding immunoassay and for the luciferase (readout) bioassay. The three TSH-R-Ab binding and bioassays highly correlated in the samples of both study groups (binding immunoassay versus luciferase bioassay r = 0.91, P < 0.001, binding vs. cyclic adenosine monophosphate (cAMP) bioassay, r = 0.86, P < 0.001, luciferase versus cAMP bioassay, r = 0.71, P = 0.006). The serological results correlated with the course of the extra-thyroidal clinical parameters of GD, i.e. clinical activity score and proptosis.

CONCLUSIONS

Targeting the FcRn markedly reduces the disease-specific TSH-R-Ab in patients with GD. The novel and rapid TSH-R-Ab bioassay improves diagnosis and management of GD patients.

Graves' disease: moving forwards

Graves' disease is a rare disorder that continues to present clinicians and families with a series of challenges. There are no new established treatments for children or adolescents, but the outcomes of recent clinical trials and meta-analyses have helped clinicians to prepare families for the road ahead. We have a more refined understanding of how to administer antithyroid drugs, which one to use and how long to treat the young person. We also have a greater insight into how best to reduce any risks associated with surgery and radioiodine. We understand more about long-term outcomes and their determinants and have greater awareness about the impact of the disease and its treatment on quality of life. A holistic approach to management is key to supporting and counselling young people and their families about the diagnosis and management options. In this review, we will discuss the recent literature and reflect on how this should be translated into clinical practice.

Recurrence risk of autoimmune thyroid and endocrine diseases

BACKGROUND AND OBJECTIVE

The recurrence risk ratio (λ) expresses the risk ratio of index patients' first-degree relatives developing a disease as compared to the general population and is a quantitative measure of the genetic contribution to the disease. This paper offers the results of a specialized center as well as a review of the pertinent literature.

METHODS

Data from 3315 consecutive subjects followed at an ORPHAN academic tertiary referral expert center for endocrine autoimmunity as well as 419 unrelated German families were collected. λ was assessed based on 806 well-documented subjects, 299 index patients with autoimmune glandular (AIGD) and non-endocrine diseases and 507 of their first-degree relatives (328 children, 179 siblings).

RESULTS

As many as 36% of relatives of patients with autoimmune diseases (AID) were affected by various autoimmune conditions. Twenty-five percent and 23% of all relatives had an AIGD or an autoimmune thyroid disease (AITD), respectively. Furthermore, 29% and 25% of relatives of index cases with polyglandular (PGA) and monoglandular (MGA) autoimmunity were affected. The recurrence risk for AITD was increased 16-fold in both children and siblings compared to the general population (λ, 95% CI 16, 11-21 and 16, 12-19, respectively). Furthermore, λ for AITD/AIGD was 21.62 (95% CI 14.17-30.69)/17.57 (11.80-24.36) and 13.48 (8.42-20.52)/10.68 (6.76-16.02) for siblings of patients with PGA and MGA, respectively. Overall, a strong genetic component for AITD and AIGD with a significant genetic impact on the development of PGA was demonstrated.

CONCLUSION

These novel results strongly recommend the screening for AITD and AIGD in children and siblings of index patients with AITD.

Teprotumumab for the treatment of thyroid eye disease

INTRODUCTION

Thyroid eye disease (TED) is an autoimmune disease characterized by inflammation of orbital and extraocular muscles. It induces proptosis and diplopia, leading to a worsening of quality of life (QoL) because of its impact on physical appearance, and visual function. The natural history involves an 'active TED,' which is an autoimmune inflammatory response targeting orbital soft tissues, and 'inactive TED,' where there is tissue expansion remodeling. To date, glucocorticoids represent the main medical therapy, even if often ineffective and associated with side effects.

AREAS COVERED

In TED, the autoimmune process leads to production of TSH-R and IGF-1 R autoantibodies. This induces inflammatory changes in the orbital tissue, and activation of fibroblasts with accumulation of glycosaminoglycans, leading to consequent proptosis, and diplopia. In two previous randomized, double-masked, placebo-controlled, parallel-group, multicenter trials, teprotumumab has been shown to be effective in improving proptosis, inflammation, diplopia, and QoL. More recently, it has been shown that teprotumumab is also effective in chronic-inactive TED. Teprotumumab was approved by the FDA on 21 January 2020 for the treatment of TED.

EXPERT OPINION

For the above-mentioned reasons teprotumumab represents a potential first line therapy for TED that could replace the use of steroids in the next future.

Cytokines in Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO), also known as thyroid eye disease (TED) or Graves' orbitopathy (GO), is a complex autoimmune condition causing visual impairment, disfigurement, and harm to patients' physical and mental health. The pathogenesis of TAO has not been fully elucidated, and the mainstream view is that coantigens shared by the thyroid and orbit trigger remodeling of extraocular muscles and orbital connective tissues through an inflammatory response. In recent years, cytokines and the immune responses they mediate have been crucial in disease progression, and currently, common evidence has shown that drugs targeting cytokines, such as tocilizumab, infliximab, and adalimumab, may be novel targets for therapy. In this review, we summarize the research development of different cytokines in TAO pathogenesis in the hope of discovering new therapeutic targets.

The Role of TPOAb in Thyroid-Associated Orbitopathy: A Systematic Review

INTRODUCTION

Thyroid-associated orbitopathy (TAO) is one of the most common autoimmune inflammatory disorders of the orbit. The presence of anti-thyroid antibodies is believed to play a role in the pathogenesis and clinical status of the TAO patients. Herein, we review the usefulness of TPOAb as a biomarker for TAO.

METHODS

A systematic search in MEDLINE library was conducted. Results: Twenty studies were included. TPO is expressed in orbital tissues, and the polymorphism rs11675434 SNP has proven to be associated with clinically evident TAO. Studies in pediatric patients have shown a positive correlation between high TPOAb levels and TAO. In contrast, results in adults are inconsistent. Some studies imply a protective role of TPOAb, yet the majority did not find any association. Some authors have suggested an implication of TPOAb in the pathophysiology of TAO in TRAb-negative patients.

CONCLUSIONS

The role of TPOAb in TAO remains unclear and controversial.

A systematic review of multimodal clinical biomarkers in the management of thyroid eye disease

Thyroid Eye Disease (TED) is an autoimmune disease that affects the extraocular muscles and periorbital fat. It most commonly occurs with Graves' Disease (GD) as an extrathyroidal manifestation, hence, it is also sometimes used interchangeably with Graves' Ophthalmopathy (GO). Well-known autoimmune markers for GD include thyroid stimulating hormone (TSH) receptor antibodies (TSH-R-Ab) which contribute to hyperthyroidism and ocular signs. Currently, apart from radiological investigations, detection of TED is based on clinical signs and symptoms which is largely subjective, with no established biomarkers which could differentiate TED from merely GD. We evaluated a total of 28 studies on potential biomarkers for diagnosis of TED. Articles included were published in English, which investigated clinical markers in tear fluid, orbital adipose-connective tissues, orbital fibroblasts and extraocular muscles, serum, thyroid tissue, as well as imaging biomarkers. Results demonstrated that biomarkers with reported diagnostic power have high sensitivity and specificity for TED, including those using a combination of biomarkers to differentiate between TED and GD, as well as the use of magnetic resonance imaging (MRI). Other biomarkers which were upregulated include cytokines, proinflammatory markers, and acute phase reactants in subjects with TED, which are however, deemed less specific to TED. Further clinical investigations for these biomarkers, scrutinising their specificity and sensitivity on a larger sample of patients, may point towards selection of suitable biomarkers for aiding detection and prognosis of TED in the future.

Prevalence of autoantibodies in patients with juvenile idiopathic arthritis: results from the German inception cohort ICON-JIA

BACKGROUND

An association of different autoimmune diseases is suspected. In juvenile idiopathic arthritis (JIA), only few and partially conflicting data on the co-existence of other autoimmune disorders are available. The prevalence of autoantibodies in patients with JIA in Germany is not known.

METHODS

Samples from 499 patients (median age at time of blood collection 11 years, median disease duration 4.4 years) in the prospective, multicenter inception cohort of children newly diagnosed with JIA (ICON-JIA) were analysed for the presence of anti-thyroid antibodies, celiac disease-specific antibodies (anti-tTG IgA, anti-tTG IgG), and connective tissue disease-associated antibodies (CTD-screen).

RESULTS

A total of 76 (15.2%) patients had either clinically diagnosed autoimmune comorbidity or elevated autoantibodies. Of 21 patients with clinical autoimmune comorbidity, only 8 were also serologically positive at the time of testing, while 55 patients had autoantibodies without clinical diagnosis. Thus, 63 patients (12.6%) had at least one elevated autoantibody. Antibodies against thyroglobulin were found in 3% and against thyreoperoxidase in 4% of the samples. TSH receptor antibodies could not be detected in any of the 499 patients. Tissue transglutaminase antibodies were elevated in 0.4% of the patients. A positive screen for CTD-specific antinuclear antibodies was found in 7%, but only rarely specific antibodies (anti-dsDNA 1.4%, anti-SS-A and -SS-B 0.2% each, anti-CENP-B 0.4%) were confirmed.

CONCLUSIONS

In our study, a specific correlation between JIA and other autoimmune phenomena could not be confirmed. The lack of well-matched control groups makes interpretation challenging. Further data need to corroborate the suspected increased risk of developing other autoimmune phenomena in JIA patients.

Clinical value of functional thyrotropin receptor antibodies in Serbian patients with Graves' orbitopathy

PURPOSE

Thyrotropin receptor autoantibodies (TSH-R-Ab) are heterogeneous in their biological function and play a significant role in the pathophysiology of both Graves' disease and Graves' orbitopathy (GO). The clinical significance and utility of determining functional TSH-R-Ab in a Serbian collective were evaluated.

METHODS

91 consecutive patients with GO were included in this study. Total TSH-R-Ab concentration, referred to as TSH-R binding inhibitory immunoglobulins (TBII) was detected using a competitive-binding immunoassay. Stimulating and blocking TSH-R-Ab (TSAb and TBAb) were measured with cell-based bioassays.

RESULTS

Stimulating TSAb activity and TBII positivity were detected in 85 of 91 (93.4%) and 65 of 91 (71.4%) patients with GO (P < 0.001). Blocking TBAb activity was observed in only one patient who expressed dual stimulating and blocking TSH-R-Ab activity. The sensitivity rates for differentiating between clinically active versus inactive and mild versus moderate-to-severe GO were 100% and 100% for TSAb, respectively. In contrast, these were 82% and 87% only for TBII. Seven of eight (87.5%) and one of eight (12.5%) euthyroid patients with GO were TSAb and TBII positive, respectively (P < 0.031). TSAb serum levels significantly predicted GO activity compared to TBII (odds ratio, OR, 95%CI: 3.908, 95%CI 1.615-9.457, P = 0.003; versus 2.133, 0.904-5.032, P = 0.084, univariate analysis; and OR 4.341, 95%CI 1.609-11.707, P = 0.004; versus 2.337, 0.889-6.145, P = 0.085 multivariate analysis).

CONCLUSION

Stimulating TSAb are highly prevalent in patients with GO and show superior clinical characteristics and predictive potential compared to the traditionally used TBII.

Diagnostic accuracy of Immulite® TSI immunoassay for thyroid-associated orbitopathy in patients with recently diagnosed Graves' hyperthyroidism

PURPOSE

The Immulite® thyroid stimulating immunoglobulin (TSI) immunoassay is a relatively new commercial assay that has shown good diagnostic accuracy in Graves' hyperthyroidism (GH). However, its clinical utility in thyroid-associated orbitopathy (TAO) is less clear. The purpose of this study was to assess the diagnostic accuracy of the Immulite® TSI immunoassay for TAO and investigate the associations between TSI and other clinical measures.

METHODS

One hundred and forty patients that had been diagnosed with GH within the previous 12 months were recruited. Identification and grading of TAO were performed at enrolment and serum samples were analysed using the Immulite® TSI immunoassay.

RESULTS

Of the 140 participants recruited, 75 (53.6%) had TAO. Age, sex and time since GH diagnosis were similar between those with and without TAO (p ≥ 0.300). TSI level tended to decrease with increasing time from GH diagnosis (Spearman's ρ - 0.28, 95% CI - 0.43, - 0.12). TSI levels were higher among those with than those without TAO (median 4.0 vs. 2.7 IU/L, respectively, p = 0.037). There was no correlation between TSI level and inflammatory index score (ρ = 0.14, 95% CI - 0.03, 0.30) or clinical severity (p = 0.527) among those with TAO. TSI level showed poor diagnostic accuracy for TAO (area under the receiver operating characteristic curve 0.60, 95% CI 0.51, 0.70).

CONCLUSIONS

Although Immulite® TSI level was higher in the presence of TAO, it showed poor diagnostic accuracy and no correlation with clinical markers of TAO severity or activity.

Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans

Soybeans are rich in proteins and lipids and have become a staple part of the human diet. Besides their nutritional excellence, they have also been shown to contain various functional components, including isoflavones, and have consequently received increasing attention as a functional food item. Isoflavones are structurally similar to 17-β-estradiol and bind to estrogen receptors (ERα and ERβ). The estrogenic activity of isoflavones ranges from a hundredth to a thousandth of that of estrogen itself. Isoflavones play a role in regulating the effects of estrogen in the human body, depending on the situation. Thus, when estrogen is insufficient, isoflavones perform the functions of estrogen, and when estrogen is excessive, isoflavones block the estrogen receptors to which estrogen binds, thus acting as an estrogen antagonist. In particular, estrogen antagonistic activity is important in the breast, endometrium, and prostate, and such antagonistic activity suppresses cancer occurrence. Genistein, an isoflavone, has cancer-suppressing effects on estrogen receptor-positive (ER+) cancers, including breast cancer. It suppresses the function of enzymes such as tyrosine protein kinase, mitogen-activated kinase, and DNA polymerase II, thus inhibiting cell proliferation and inducing apoptosis. Genistein is the most biologically active and potent isoflavone candidate for cancer prevention. Furthermore, among the various physiological functions of isoflavones, they are best known for their antioxidant activities. S-Equol, a metabolite of genistein and daidzein, has strong antioxidative effects; however, the ability to metabolize daidzein into S-equol varies based on racial and individual differences. The antioxidant activity of isoflavones may be effective in preventing dementia by inhibiting the phosphorylation of Alzheimer's-related tau proteins. Genistein also reduces allergic responses by limiting the expression of mast cell IgE receptors, which are involved in allergic responses. In addition, they have been known to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. Further, it also has positive effects on menstrual irregularity in non-menopausal women and relieving menopausal symptoms in middle-aged women. Recently, soybean consumption has shown steep increasing trend in Western countries where the intake was previously only 1/20-1/50 of that in Asian countries. In this review, I have dealt with the latest research trends that have shown substantial interest in the biological efficacy of isoflavones in humans and plants, and their related mechanisms.

A cyclic peptide significantly improves thyroid function, thyrotropin-receptor antibodies and orbital mucine /collagen content in a long-term Graves' disease mouse model

BACKGROUND

BALB/c mice which received long-term immunizations of adenovirus (Ad) expressing thyrotropin receptor A-subunits (TSHR) developed stable Graves' disease (GD). TSHR-derived cyclic peptide 19 (P19) was identified as effective therapy in this model.

METHODS

In Ad-TSHR mice, we investigated shorter disease intervals up to 4 months for histological alterations of the orbits, fine tuning of anti-TSHR antibodies (Ab) and free thyroxine (fT4) hormone levels by using novel detection methods in an independent laboratory. Therapy (0.3 mg/kg P19 or vehicle) was given intravenously after the fourth Ad-TSHR immunization (week 11) and continued until week 19.

RESULTS

Thyrotropin binding inhibitory immunoglobulins (TBII, bridge immunoassay), blocking (TBAb) and stimulating (TSAb) TSHR-Ab (both cell-based bioassays) and serum levels of fT4 were significantly elevated at week 11 in Ad-TSHR-immunized mice versus none in control mice. For the first time, TSAb, TBAb, and thyroperoxidase-Ab were detected in 17 of 19, 12/19 and 6/19 Ad-TSHR immunized mice, respectively at week 21. Also, for the first time, this study showed that P19 treatment markedly reduced serum TBII (p < 0.0001), serum fT4 (p = 0.02), and acidic mucins and collagen content in the orbital tissue of Ad-TSHR-immunized mice.

CONCLUSION

P19 significantly improved thyroid function, confirming previous results in an independent second laboratory. A relevant shift of anti-TSHR antibody subpopulations in response to P19 therapy may help explain its immunological effects. Moreover, P19 exerted a beneficial effect on mucine and collagen content of orbital tissue. Hence, P19 offers a potential novel therapeutic approach for GD and associated orbitopathy.

Intravenous rituximab therapy for active Graves' ophthalmopathy: a meta-analysis

AIM

The successful treatment of Graves' ophthalmopathy (GO) remains a challenge, while the efficacy of rituximab (RTX) is at present controversial. The aim of this meta-analysis was to investigate the potential impact of intravenous RTX therapy in patients with GO.

METHODS

We performed a search in the PubMed, Embase, and Web of Science databases for relevant studies published before July 2020. The primary outcome was the change of clinical activity score (CAS), and secondary outcomes were the change of proptosis and TSH receptor antibodies (TRAb). A meta-analysis was conducted to calculate the standard mean difference (SMD) for these outcomes by using fixed- or random-effect models.

RESULTS

Analysis of outcomes in 152 patients collected from 12 published articles was conducted. Compared to baseline value, CAS was significantly decreased at 1, 6, 12, and >12 months after RTX treatment. For proptosis, the results revealed no significant decrease at 1-3, 6, and ≥12 months. Moreover, the pooled analysis employed in this meta-analysis showed no significant difference of TRAb at 1 month, but significant declines were observed at 6 and ≥12 months.

CONCLUSION

Our results strongly suggest that intravenous RTX treatment has an acute and long-lasting beneficial effect on decreasing both CAS and TRAb. The study also indicates that the effect of RTX on proptosis is limited. There is evidently a need to investigate the mechanism behind RTX ineffectiveness on proptosis and explore other therapeutic regimens for the reduction of proptosis.

Thyrotropin receptor antibodies and Graves' orbitopathy

CONTEXT AND PURPOSE

The thyrotropin receptor (TSHR) is the key autoantigen in Graves' disease (GD) and associated orbitopathy (GO). Antibodies targeting the TSHR (TSHR-Ab) impact the pathogenesis and the course of GO. This review discusses the role and clinical relevance of TSHR-Ab in GO.

METHODS

Review of the current and pertinent literature.

RESULTS

GO is the most common extrathyroidal manifestation of GD and is caused by persistent, unregulated stimulation of TSHR-expressing orbital target cells (e.g. fibroblasts and pre-adipocytes). Serum TSHR-Ab and more specifically, the stimulatory Ab (TSAb) are observed in the vast majority of patients with GD and GO. TSHR-Ab are a sensitive serological parameter for the differential diagnosis of GO. TSHR-Ab can be detected either with conventional binding immunoassays that measure binding of Ab to the TSHR or with cell-based bioassays that provide information on their functional activity and potency. Knowledge of the biological activity and not simply the presence or absence of TSHR-Ab has relevant clinical implications e.g. predicting de-novo development or exacerbation of pre-existing GO. TSAb are specific biomarkers of GD/GO and responsible for many of its clinical manifestations. TSAb strongly correlate with the clinical activity and clinical severity of GO. Further, the magnitude of TSAb indicates the onset and acuity of sight-threatening GO (optic neuropathy). Baseline serum values of TSAb and especially dilution analysis of TSAb significantly differentiate between thyroidal GD only versus GD + GO.

CONCLUSION

Measurement of functional TSHR-Ab, especially TSAb, is clinically relevant for the differential diagnosis and management of GO.

RAGE and HMGB1 Expression in Orbital Tissue Microenvironment in Graves' Ophthalmopathy

Graves' ophthalmopathy (GO) is a chronic autoimmune inflammatory disorder involving orbital tissues. A receptor for advanced glycation end products (RAGE) and its ligand high mobility group box 1 (HMGB1) protein trigger inflammation and cell proliferation and are involved in the pathogenesis of various chronic inflammatory diseases. This study was aimed to evaluate RAGE and HMGB1 expression in GO to determine its potential clinical significance. To the best of our knowledge, this is the first study showing RAGE and HMGB1 expression in orbital tissue using immunohistochemistry. Sections of orbital adipose tissue obtained from patients diagnosed with GO (23 patients; 36 orbits) and normal controls (NC) (15 patients; 15 orbits) were analyzed by immunohistochemistry for RAGE and HMGB1 expression. Expression profiles were then correlated with clinical data of the study group. RAGE and HMGB1 expression were elevated in GO patients in comparison with NC (p = 0.001 and p = 0.02, respectively). We observed a correlation between RAGE expression and occurrence of dysthyroid optic neuropathy (DON) (p = 0.05) and levels of TSH Receptor Antibodies (TRAb) (p = 0.01). Overexpression of RAGE and HMGB1 might be associated with GO pathogenesis. In addition, RAGE and HMGB1 proteins may be considered as promising therapeutic targets, but this requires further research.

The role of laboratory medicine in the diagnosis of the hyperthyroidism

Hyperthyroidism is a clinical condition characterized by inappropriately high synthesis and secretion of thyroid hormones by the thyroid gland. It has multiple aetiologies, manifestations and potential therapies. Graves' disease is the most common form of hyperthyroidism, due to the production of autoantibodies against thyrotropin receptor, capable of over-stimulating thyroid function. A reliable diagnosis of hyperthyroidism can be established on clinical grounds, followed by the evaluation of serum thyroid function tests (thyrotropin first and then free thyroxine, adding the measurement of free triiodothyronine in selected specific situations). The recent guidelines of both the American and European Thyroid Associations have strongly recommended the measurement of thyrotropin receptor autoantibodies for the accurate diagnosis and management of Graves' disease. If autoantibody test is negative, a radioiodine uptake should be performed. Considering the most recent laboratory improvements, binding assays can be considered the best first solution for the measurement of thyrotropin receptor autoantibodies in diagnosis and management of overt cases of Graves' disease. In fact, they have a satisfactory clinical sensitivity and specificity (97.4% and 99.2%, respectively) being performed in clinical laboratories on automated platforms together with the other thyroid function tests. In this setting, the bioassays should be reserved for fine and complex diagnoses and for particular clinical conditions where it is essential to document the transition from stimulating to blocking activity or vice versa (e.g. pregnancy and post-partum, related thyroid eye disease, Hashimoto's thyroiditis with extrathyroidal manifestations, unusual cases after LT4 therapy for hypothyroidism or after antithyroid drug treatment for Graves' disease). Undoubtedly, technological advances will help improve laboratory diagnostics of hyperthyroidism. Nevertheless, despite future progress, the dialogue between clinicians and laboratory will continue to be crucial for an adequate knowledge and interpretation of the laboratory tests and, therefore, for an accurate diagnosis and correct management of the patient.

Type 1 Diabetes and Autoimmune Thyroid Disease-The Genetic Link

Type 1 diabetes (T1D) and autoimmune thyroid disease (AITD) are the most frequent chronic autoimmune diseases worldwide. Several autoimmune endocrine and non-endocrine disorders tend to occur together. T1D and AITD often cluster in individuals and families, seen in the formation of autoimmune polyendocrinopathy (AP). The close relationship between these two diseases is largely explained by sharing a common genetic background. The HLA antigens DQ2 (DQA1*0501-DQB1*0201) and DQ8 (DQA1*0301-DQB1*0302), tightly linked with DR3 and DR4, are the major common genetic predisposition. Moreover, functional single nucleotide polymorphisms (or rare variants) of various genes, such as the cytotoxic T-lymphocyte- associated antigen (CTLA4), the protein tyrosine phosphatase non-receptor type 22 (PTPN22), the interleukin-2 Receptor (IL2Ra), the Vitamin D receptor (VDR), and the tumor-necrosis-factor-α (TNF) that are involved in immune regulation have been identified to confer susceptibility to both T1D and AITD. Other genes including cluster of differentiation 40 (CD40), the forkhead box P3 (FOXP3), the MHC Class I Polypeptide-Related Sequence A (MICA), insulin variable number of tandem repeats (INS-VNTR), the C-Type Lectin Domain Containing 16A (CLEC16A), the Erb-B2 Receptor Tyrosine Kinase 3 (ERBB3) gene, the interferon-induced helicase C domain-containing protein 1 (IFIH1), and various cytokine genes are also under suspicion to increase susceptibility to T1D and AITD. Further, BTB domain and CNC homolog 2 (BACH2), C-C motif chemokine receptor 5 (CCR5), SH2B adaptor protein 3 (SH2B3), and Rac family small GTPase 2 (RAC2) are found to be associated with T1D and AITD by various independent genome wide association studies and overlap in our list, indicating a strong common genetic link for T1D and AITD. As several susceptibility genes and environmental factors contribute to the disease aetiology of both T1D and AITD and/or AP subtype III variant (T1D+AITD) simultaneously, all patients with T1D should be screened for AITD, and vice versa.

A Novel Long-Term Graves' Disease Animal Model Confirmed by Functional Thyrotropin Receptor Antibodies

INTRODUCTION

A novel long-term murine model for Graves' disease (GD) using repeated, long-term immunizations with recombinant adenovirus expressing the extracellular A-subunit of the human thyrotropin receptor (Ad-TSHR) was applied to evaluate the functional anti-TSHR-antibody (TSHR-Ab) profile.

METHODS

BALB/c mice received 7 immunizations with either 10¹⁰ plaque-forming units of Ad-TSHR or control Ad-GFP. Naïve (nonimmuized native) mice were also studied. Three 3-weekly immunizations were followed by 4-weekly boosts until the 7th immunization. Blocking (TBAb) and stimulating (TSAb) TSHR-Ab were measured with bioassays. Assay cut-offs for TBAb/TSAb were at 34% inhibition and a specimen-to-reference ratio (SRR) of 140%.

RESULTS

Nineteen (8 Ad-TSHR-, 4 Ad-GFP-immunized, and 7 native) mice were investigated. All native mice were negative for TSHR-binding inhibitory immunoglobulins (TBII) prior to immunization. Native and Ad-GFP mice were negative in weeks 17 and 27 for TBII and TBAb/TSAb. In native mice, the free thyroxine (fT4) levels (median [25th percentile; 75th percentile]) were in the upper normal range (1.2 ng/mL [1.1; 1.6]) prior to immunization, at weeks 17 (2.2 ng/mL [2.1; 2.4]) and 27 (1.4 ng/mL [1.1; 1.7]), respectively. In contrast, in Ad-TSHR-immunized mice, fT4 values were markedly increased at weeks 17 (4.4 ng/mL [3.9; 6]) and 27 (4.5 ng/mL [4.2; 6]) compared to those in Ad-GFP mice (2 ng/mL [1.8; 2.1] and 1.4 ng/mL [1.1; 1.6]), respectively (p = 0.0008, p = 0.001). In contrast, at week 17, in Ad-TSHR mice, the mean TBII, TBAb, and TSAb levels were 40 IU/L (40; 40); 62% inhibition (38; 69), and 116% SRR (97; 185), respectively; at week 27, they were 40 IU/L (39; 40); 65% inhibition (34; 80) and 95% SRR (63; 187), respectively. Three serum samples from Ad-TSHR mice (38%) demonstrated dual TBAb/TSAb positivity.

CONCLUSIONS

TBAb/TSAb were highly prevalent in Ad-TSHR-immunized mice, thus confirming the successful establishment of a novel, long-term murine model for GD. All TBAb- and TSAb-positive Ad-TSHR-immunized mice were TBII-positive. Thus, the binding immunoassay did not differentiate between TSHR-Ab functionality.

Management of Graves Thyroidal and Extrathyroidal Disease: An Update

CONTEXT

Invited update on the management of systemic autoimmune Graves disease (GD) and associated Graves orbitopathy (GO).

EVIDENCE ACQUISITION

Guidelines, pertinent original articles, systemic reviews, and meta-analyses.

EVIDENCE SYNTHESIS

Thyrotropin receptor antibodies (TSH-R-Abs), foremost the stimulatory TSH-R-Abs, are a specific biomarker for GD. Their measurement assists in the differential diagnosis of hyperthyroidism and offers accurate and rapid diagnosis of GD. Thyroid ultrasound is a sensitive imaging tool for GD. Worldwide, thionamides are the favored treatment (12-18 months) of newly diagnosed GD, with methimazole (MMI) as the preferred drug. Patients with persistently high TSH-R-Abs and/or persistent hyperthyroidism at 18 months, or with a relapse after completing a course of MMI, can opt for a definitive therapy with radioactive iodine (RAI) or total thyroidectomy (TX). Continued long-term, low-dose MMI administration is a valuable and safe alternative. Patient choice, both at initial presentation of GD and at recurrence, should be emphasized. Propylthiouracil is preferred to MMI during the first trimester of pregnancy. TX is best performed by a high-volume thyroid surgeon. RAI should be avoided in GD patients with active GO, especially in smokers. Recently, a promising therapy with an anti-insulin-like growth factor-1 monoclonal antibody for patients with active/severe GO was approved by the Food and Drug Administration. COVID-19 infection is a risk factor for poorly controlled hyperthyroidism, which contributes to the infection-related mortality risk. If GO is not severe, systemic steroid treatment should be postponed during COVID-19 while local treatment and preventive measures are offered.

CONCLUSIONS

A clear trend towards serological diagnosis and medical treatment of GD has emerged.

Long-term outcomes of graves disease in children treated with anti-thyroid drugs

BACKGROUND

Graves disease (GD) is the most common cause of thyrotoxicosis in children and adolescents, accounting for 15% of all thyroid diseases during childhood. Anti-thyroid drugs (ATD) are recommended as the first-line treatment in children and adolescents. However, the remission rate is lower in children than in adults, and the optimal treatment duration and favorable factors associated with remission remain unknown. We aimed to investigate long-term outcomes of pediatric GD patients receiving ATD.

METHODS

We retrospectively reviewed medical charts of 396 GD subjects from 1985 to 2017 at MacKay Children's Hospital. Ninety-six patients were excluded from the analyses, including 71 patients followed for less than one year, 6 patients who received radioactive therapy and 19 patients who received surgery. The remaining 300 patients initially treated with ATD and followed up for more than 1 year constituted our study population.

RESULTS

The 300 patients comprised 257 (85.7%) females and 43 (14.3%) males. Their median age at diagnosis was 11.6 (range 2.7-17.8) years with 11 patients (3.7%) younger than 5 years. Their median follow-up period was 4.7 (range 1.1-23.9) years. Overall, 122 patients achieved the criteria for discontinuing ATD treatment, and seventy-nine (39.9%) patients achieved remission, with a median follow-up period of 5.3 (range 1.5-20.1) years. Patients in the remission group were more likely to be aged <5 years (remission vs. relapse vs. ongoing ATD; 11.4 vs. 0 vs. 2.6%, P = 0.02), less likely to have a family history of thyroid disease (24.1 vs. 42.1 vs. 52.6%, P = 0.001), and had lower TSH receptor antibody (TRAb) levels (42.8 vs. 53.6 vs. 65.1%, P = 0.02) at the time of diagnosis.

CONCLUSION

Long-term ATD remains an effective treatment option for GD in children. Pediatric GD patients aged <5 years, having no family history of thyroid disease and having initial lower TRAb levels were more likely to achieve remission.

Prospective Trial of Functional Thyrotropin Receptor Antibodies in Graves Disease

CONTEXT

Scarce data exist regarding the relevance of stimulatory (TSAb) and blocking (TBAb) thyrotropin receptor antibodies in the management of Graves disease (GD).

OBJECTIVE

To evaluate the clinical utility and predictive value of TSAb/TBAb.

DESIGN

Prospective 2-year trial.

SETTING

Academic tertiary referral center.

PATIENTS

One hundred consecutive, untreated, hyperthyroid GD patients.

METHODS

TSAb was reported as percentage of specimen-to-reference ratio (SRR) (cutoff SRR < 140%). Blocking activity was defined as percent inhibition of luciferase expression relative to induction with bovine thyrotropin (TSH, thyroid stimulating hormone) alone (cutoff > 40% inhibition).

MAIN OUTCOME MEASURES

Response versus nonresponse to a 24-week methimazole (MMI) treatment defined as biochemical euthyroidism versus persistent hyperthyroidism at week 24 and/or relapse at weeks 36, 48, and 96.

RESULTS

Forty-four patients responded to MMI, of whom 43% had Graves orbitopathy (GO), while 56 were nonresponders (66% with GO; P < 0.01). At baseline, undiluted serum TSAb but not thyroid binding inhibitory immunoglobulins (TBII) differentiated between thyroidal GD-only versus GD + GO (P < 0.001). Furthermore, at baseline, responders demonstrated marked differences in diluted TSAb titers compared with nonresponders (P < 0.001). During treatment, serum TSAb levels decreased markedly in responders (P < 0.001) but increased in nonresponders (P < 0.01). In contrast, TBII strongly decreased in nonresponders (P = 0.002). All nonresponders and/or those who relapsed during 72-week follow-up period were TSAb-positive at week 24. A shift from TSAb to TBAb was noted in 8 patients during treatment and/or follow-up and led to remission.

CONCLUSIONS

Serum TSAb levels mirror severity of GD. Their increase during MMI treatment is a marker for ongoing disease activity. TSAb dilution analysis had additional predictive value.

A Novel Anti-CD40 Monoclonal Antibody, Iscalimab, for Control of Graves Hyperthyroidism-A Proof-of-Concept Trial

CONTEXT

The CD40-CD154 co-stimulatory pathway plays an important role in the pathogenesis of Graves disease (GD) by promoting autoreactive B-cell activation.

OBJECTIVE

Evaluate efficacy and safety of a human, blocking, nondepleting anti-CD40 monoclonal antibody, iscalimab, in hyperthyroid patients with GD.

DESIGN

Open-label, phase II proof-of-concept study.

SETTING

Multicenter.

PATIENTS

Fifteen with GD.

INTERVENTION

Patients received 5 doses of iscalimab at 10 mg/kg intravenously over 12 weeks.

MAIN OUTCOME MEASURES

Thyroid-related hormones and autoantibodies, plasma soluble CD40, free CD40 on B cells, soluble CXCL13, pharmacokinetics, and safety were assessed.

RESULTS

The iscalimab intervention resulted in complete CD40 engagement for up to 20 weeks. A clinical response and biochemical euthyroidism was observed in 7 of 15 (47%) patients. Free and total triiodothyronine and thyroxine normalized in 7 patients who did not receive any rescue medication with antithyroid drugs (ATD), and 2/15 (13.3%) showed normal thyrotropin. Six (40%) patients required ATD. Four of 7 responders relapsed after treatment completion. Serum concentrations of thyrotropin receptor autoantibodies (TSH-R-Ab) significantly declined in all patients (mean 15.3 IU/L vs 4.0 IU/L, 66% reduction; P < 0.001) and TSH-R-Ab levels normalized in 4 (27%). Thyroperoxidase and thyroglobulin autoantibodies significantly decreased in responders. Iscalimab rapidly reduced serum CXCL13 concentrations (P < 0.001). Twelve (80.0%) patients reported at least 1 adverse event (AE). All treatment-related AE were mild or moderate and resolved by end of the study.

CONCLUSION

Iscalimab was generally safe and clinically effective in a subgroup of hyperthyroid GD patients. The potential therapeutic benefit of iscalimab should be further tested.

Graves' disease: developments in first-line antithyroid drugs in the young

Introduction: First-line treatment for most young people with Graves' disease (GD) will include the administration of a thionamide antithyroid medication (ATD); Carbimazole (CBZ), Methimazole (MMZ), or rarely, propylthiouracil (PTU). GD is a challenge for families and clinicians because the likelihood of remission following a course of ATD is lower in young people when compared to adults, yet the risk of adverse events is higher. An overall consensus regarding the optimal ATD treatment regimen is lacking; how ATD are prescribed, for how long and how the associated risk of adverse events is managed varies between clinicians, units and nations. This partly reflects clinician and family uncertainty regarding outcomes.Areas covered: This review will focus on some of the key articles published in the field of thionamide ATD in children. It will highlight key issues that need to be discussed with families as well as addressing the approach and controversies in the treatment of GD. This article does not reflect a formal systematic review of the literature.Expert opinion: New strategies in areas such as immunomodulation may see the development of new antithyroid drug treatments that, either in isolation or in combination with thionamide therapy, may increase the likelihood of long-term remission.

Comparison of a Novel Homogeneous Cyclic Amp Assay and a Luciferase Assay for Measuring Stimulating Thyrotropin-Receptor Autoantibodies

OBJECTIVE

Stimulating thyrotropin-receptor antibodies (TSAb) cause Graves' disease (GD). We tested a novel homogeneous fluorescent 3',5' cyclic adenine monophosphate (cAMP) assay for the detection of TSAb in a bioassay.

METHODS

Chinese hamster ovary (CHO) cell lines expressing either a chimeric (MC4) or wild-type (WT) TSH-R were incubated with the adenyl cyclase activator forskolin, a human TSAb monoclonal antibody (M22), and with sera from GD patients. Intracellular cAMP levels were measured using a Bridge-It® cAMP assay, and the results were compared with a luciferase-based bioassay.

RESULTS

Both cell lines were stimulated with forskolin concentrations (0.006-200 µM) in a dose-dependent manner. The linear range in the MC4 and WT cells was 0.8-25 and 3.1-50 µM, respectively. Levels of cAMP and luciferase in forskolin-treated MC4 and WT cells were positively correlated (r = 0.91 and 0.84, both p < 0.001). The 50% maximum stimulatory concentration of forskolin was more than 16-fold higher for the CHO-WT cells than the CHO-MC4 cells in the cAMP assay and 4-fold higher in the luciferase assay. Incubation of both cell lines with M22 (0.006-50 ng/mL) resulted in a dose-dependent increase in cAMP levels with linear ranges for the MC4 and WT cells of 0.8-12.5 and 0.2-3.125 ng/mL, respectively. Comparison of cAMP and luciferase levels in M22-treated MC4 and WT cells also showed a positive correlation (r = 0.88, p < 0.001 and 0.75, p = 0.002). A positive correlation was also noted when using patient samples (r = 0.96, p < 0.001) that were all TSH-R-Ab binding assay positive.

CONCLUSION

The novel, rapid, simple-to-perform cAMP assay provides TSAb-mediated stimulatory results comparable to a luciferase-based bioassay.

Glucocorticoids in Graves' orbitopathy: mechanisms of action and clinical application

BACKGROUND

Graves' orbitopathy (GO) is the most frequent extrathyroidal manifestation of the autoimmune Graves' disease. GO significantly impacts quality of life and has a psycho-social morbidity. Inflammation and swelling of the orbital tissue often leads to proptosis, diplopia, and decrease of visual acuity. Due to the inflammatory background of the disease, glucocorticoids (GC) have been used as a first-line treatment for decades.

METHODS

PubMed and MeSH database were searched for original articles, clinical trials, reviews, and meta-analyses published between 1 January 2000 and 31 March 2020 and pertaining to both the mechanism of action and immunological effects of GC as well as to the treatment of GO by GC. The publications were evaluated according to their setting and study design.

RESULTS

GC act through genomic (trans-activation and trans-repression) and rapid non-genomic mechanisms. GC in general, and the intravenous (IV) administration of GC in particular, markedly decrease the activity and number of the most potent antigen-presenting dendritic cells. According to the internationally acknowledged European Thyroid Association Guidelines for the management of GO, weekly IVGC application over 12 weeks is recommended as first-line treatment for patients with active and severe GO. The daily and cumulative dose should be tailored according to clinical severity, for example, 4.5 g of IV methylprednisolone for the inflammatory component versus 7.5 g in the presence of diplopia and severe proptosis. Fast and significant improvements in orbital symptoms and signs are noted in 65-70% of patients. Long-term experience over decades, and worldwide availability at low cost, underline the clinical and therapeutic relevance of GC. Adverse events are rarely severe, dose-dependent, and usually reversible, hence easy to handle by medical investigators. Oral GC application on a daily basis is characterized by high bioavailability but reduced efficacy and increased toxicity.

CONCLUSION

IVGC still represents the standard of care in active/severe GO. Innovative biologicals, like monoclonal antibodies targeting the thyrotropin/Insulin-like growth factor-1 receptors or pro-inflammatory cytokines (e.g., Interleukin-6) should be compared with standard GC treatment with respect to short- and long-term efficacy, safety, costs, and global availability.

Thyroid Peroxidase Revisited - What's New?

Thyroid peroxidase (TPO) is an enzyme that participates in thyroid hormone biosynthesis. TPO is also a major autoantigen in autoimmune thyroid diseases (AITD). In this review, we summarize the latest developments in the field of TPO research. We present the current understanding of immunodominant serologic determinants, frequency of TPO-specific autoantibodies in the population, as well as genetic and environmental factors contributing to their development. Moreover, we report recent progress in the clinical utilities of TPO autoantibody testing, including thyroid dysfunctions and extra-thyroidal disorders.

Autoimmune polyglandular diseases

Autoimmune polyglandular diseases (APD) are defined as the presence of two autoimmune -induced endocrine failures. With respect to the significant morbidity and potential mortality of APD, the diagnostic objective is to detect APD at an early stage, with the advantage of less frequent complications, effective therapy and better prognosis. This requires that patients at risk be regularly screened for subclinical endocrinopathies prior to clinical manifestation. Regarding the time interval between manifestation of first and further endocrinopathies, regular and long-term follow-up is warranted. Quality of life and psychosocial status are poor in APD patients and involved relatives. Familial clustering is high in patients with APD. Considering the high incidence of one or more endocrinopathies in first-degree relatives of patients with APD, family members should be regularly screened since they may also develop autoimmune endocrinopathies. Multidisciplinary management of these multiplex families in specialized centers is warranted.

Immunological Aspects of Graves' Ophthalmopathy

The body's autoimmune process is involved in the development of Graves' disease (GD), which is manifested by an overactive thyroid gland. In some patients, autoreactive inflammatory reactions contribute to the development of symptoms such as thyroid ophthalmopathy, and the subsequent signs and symptoms are derived from the expansion of orbital adipose tissue and edema of extraocular muscles within the orbit. The autoimmune process, production of antibodies against self-antigens such as TSH receptor (TSHR) and IGF-1 receptor (IGF-1R), inflammatory infiltration, and accumulation of glycosaminoglycans (GAG) lead to edematous-infiltrative changes in periocular tissues. As a consequence, edema exophthalmos develops. Orbital fibroblasts seem to play a crucial role in orbital inflammation, tissue expansion, remodeling, and fibrosis because of their proliferative activity as well as their capacity to differentiate into adipocytes and myofibroblasts and production of GAG. In this paper, based on the available medical literature, the immunological mechanism of GO pathogenesis has been summarized. Particular attention was paid to the role of orbital fibroblasts and putative autoantigens. A deeper understanding of the pathomechanism of the disease and the involvement of immunological processes may give rise to the introduction of new, effective, and safe methods of treatment or monitoring of the disease activity.

Immunotherapies for thyroid eye disease

PURPOSE OF REVIEW

Thyroid eye disease is a complex autoimmune disorder which causes substantial morbidity. It can result in orbital disfigurement, double vision, and visual loss. Consequently, it has a substantial negative effect on quality of life, mental health, and socioeconomic status. Most signs and symptoms of thyroid eye disease (TED) can be explained by the expansion of the orbital contents. Steroids are the mainstay of treatment in TED. However, recurrence may occur once steroids are withdrawn. Furthermore, in most cases, normal orbital anatomy is not restored, and skilled rehabilitative surgery is required to reduce disfigurement, double vision, and to preserve vision. Therefore, novel, causal, and more efficacious treatment strategies are warranted.

RECENT FINDINGS

In the last decade, the pathophysiology of TED has also been revised with the identification of new potential therapeutic targets. Recent clinical trials have shown that considerable benefit may be derived from the addition of antiproliferative agents (e.g., mycophenolate sodium) in preventing deterioration after steroid cessation. In addition, targeted biologic therapies have shown promise, including teprotumumab (anti-IGFR) which appears to substantially reduce proptosis, rituximab (anti-CD20) which reduces inflammation and tocilizumab (anti-IL-6) which potentially benefits both of these parameters.

SUMMARY

This short review summarizes the recent research developments in this area.

Autoimmune Polyendocrinopathy

CONTEXT

This mini-review offers an update on the rare autoimmune polyendocrinopathy (AP) syndrome with a synopsis of recent developments.

DESIGN AND RESULTS

Systematic search for studies related to pathogenesis, immunogenetics, screening, diagnosis, clinical spectrum, and epidemiology of AP. AP (orphan code ORPHA 282196) is defined as the autoimmune-induced failure of at least two glands. AP is divided into the rare juvenile type I and the adult types II to IV. The prevalence is 1:100,000 and 1:20,000 for types I and types II to IV, respectively. Whereas type I (ORPHA 3453) is a monogenetic syndrome with an autosomal recessive transmission related to mutations in the autoimmune regulator (AIRE) gene, types II to IV are genetically complex multifactorial syndromes that are strongly associated with certain alleles of HLA genes within the major histocompatibility complex located on chromosome 6, as well as the cytotoxic T lymphocyte antigen 4 and the protein tyrosine phosphatase nonreceptor type 22 genes. Addison disease is the major endocrine component of type II (ORPHA 3143), whereas the coexistence of type 1 diabetes and autoimmune thyroid disease is characteristic for type III (ORPHA 227982). Genetic screening for the AIRE gene is useful in patients with suspected type I, whereas serological screening (i.e., diabetes/adrenal antibodies) is required in patients with monoglandular autoimmunity and suspected AP. If positive, functional endocrine testing of the antibody-positive patients as well as serological screening of their first-degree relatives is recommended.

CONCLUSION

Timely diagnosis, genetic counseling, and optimal long-term management of AP is best offered in specialized centers.

High Titers of Thyrotropin Receptor Antibodies Are Associated With Orbitopathy in Patients With Graves Disease

CONTEXT

Serum TSH receptor autoantibody (TSH-R-Ab) is a biomarker of Graves disease (GD). Studies have shown that the levels of this TSH-R-Ab have clinical significance.

OBJECTIVE

To differentiate between thyroidal GD only and Graves orbitopathy (GD + GO).

DESIGN

Controlled, follow-up study.

SETTING

Academic tertiary referral center for GD + GO.

SUBJECTS

Sixty patients with GD, GD + GO, and controls.

INTERVENTION

Serial serum dilution analyses with six automated, ELISA, and cell-based assays for TSH-R-Ab.

MAIN OUTCOME MEASURE

Differentiation among GD phenotypes.

RESULTS

All undiluted samples of hyperthyroid-untreated GD patients were positive with the six assays but became negative at dilution 1:9 in four of six assays. In contrast, all undiluted samples of hyperthyroid-untreated GD + GO patients remained positive up to dilution 1:81, P < 0.001. At high dilutions 1:243, 1:729, 1:2187, and 1:6561, the rate of stimulating TSH-R-Ab positivity in the bioassay for GD + GO patients was 75%, 35%, 5%, and 0%, respectively (all P < 0.001). The five ELISA and/or automated assays confirmed this marked difference of anti-TSH-R-Ab detection between GD-only and GD + GO. In comparison, the baseline-undiluted samples of GD vs GD + GO showed an overlap in the ranges of TSH-R-Ab levels. Subsequent to 12-month methimazole treatment, samples from euthyroid GD + GO patients were still TSH-R-Ab positive at the high dilution of 1:243. In contrast, all GD samples were negative already at dilution 1:3. A GD patient with TSH-R-Ab positivity at dilution 1:729 developed de novo GO.

CONCLUSIONS

TSH-R-Ab titers, as determined by dilution analysis, significantly differentiate between GD and GD + GO.

Thyrotropin Receptor Blocking Antibodies

Autoantibodies (Ab) against the thyroid-stimulating hormone receptor (TSHR) are frequently found in autoimmune thyroid disease (AITD). Autoantibodies to the TSHR (anti-TSHR-Ab) may mimic or block the action of TSH or be functionally neutral. Measurement of anti-TSHR-Ab can be done either via competitive-binding immunoassays or with functional cell-based bioassays. Antibody-binding assays do not assess anti-TSHR-Ab functionality, but rather measure the concentration of total anti-TSHR binding activity. In contrast, functional cell-based bioassays indicate whether anti-TSHR-Ab have stimulatory or blocking activity. Historically bioassays for anti-TSHR-Ab were research tools and were used to study the pathophysiology of Graves' disease and Hashimoto's thyroiditis. In the past, bioassays for anti-TSHR-Abs were laborious and time-consuming and varied widely in performance from laboratory to laboratory. Recent advances in the development of cell-based assays, including the application of molecular engineering, have led to significant improvements that have enabled bioassays to be employed routinely in clinical laboratories. The prevalence and functional significance of TSHR blocking autoantibodies (TBAb) in autoimmune hypothyroidism has been less well investigated compared to TSHR stimulating Ab. There is an increasing body of data, however, that demonstrate the clinical utility and relevance of TBAb, and thus the importance of TBAb bioassays, in the diagnosis and management of patients with AITD. In the present review, we summarize the different methods used to measure TBAb, and discuss their prevalence and clinical relevance.

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.

Celiac disease and endocrine autoimmunity - the genetic link

Celiac disease is a small intestinal inflammatory disease with autoimmune features that is triggered and maintained by the ingestion of the storage proteins (gluten) of wheat, barley and rye. The prevalence of celiac disease is increased in patients with monoglandular and/or polyglandular autoimmunity and their relatives. Between 10 and 30% of patients with celiac disease are thyroid and/or type 1 diabetes antibody positive, while around 5 to 7% of patients with autoimmune thyroid disease and/or type 1 diabetes are IgA anti-tissue transglutaminase antibody positive. The close relationship between celiac disease and endocrine autoimmunity is largely explained by sharing a common genetic background. The HLA antigens DQ2 (DQA1*0501-DQB1*0201) and/or DQ8 (DQA1*0301-DQB1*0302), that are tightly linked to DR3 and DR4, respectively, are the major common genetic predisposition. Moreover, functional single nucleotide polymorphisms of various genes that are involved in immune regulation have been identified as "overlap" susceptibility genes for both celiac disease and monoglandular or polyglandular autoimmunity. While plausible, it remains to be established how far a gluten free diet may prevent or ameliorate glandular autoimmunity. In conclusion, all patients with celiac disease should be screened for type 1 diabetes and/or autoimmune thyroid disease. Conversely, patients with the above autoimmune endocrine disorders should be also screened for celiac disease.

Stimulatory TSH-Receptor Antibodies and Oxidative Stress in Graves Disease

CONTEXT

We hypothesized that TSH-receptor (TSHR) stimulating antibodies (TSAbs) are involved in oxidative stress mechanisms in patients with Graves disease (GD).

METHODS

Nicotinamide adenine dinucleotide phosphate oxidase, isoform 2 (NOX2); oxidative parameters; and oxidative burst were measured in serum, urine, and whole blood from patients with GD and control subjects. Superoxide production was investigated in human embryonic kidney (HEK)-293 cells stably overexpressing the TSHR. Lipid peroxidation was determined by immunodot-blot analysis for protein-bound 4-hydroxy-2-nonenal (4-HNE) in human primary thyrocytes and HEK-293-TSHR cells.

RESULTS

Serum NOX2 levels were markedly higher in hyperthyroid untreated vs euthyroid treated patients with GD, hyperthyroid patients with toxic nodular goiter, and euthyroid healthy control subjects (all P < 0.0001). Urine oxidative parameters were increased in patients with GD vs patients with toxic goiter (P < 0.01) and/or control subjects (P < 0.001). The maximum of the zymosan A- and phorbol 12,13-dibutyrate-induced respiratory burst of leukocytes was 1.5-fold higher in whole blood from hyperthyroid patients with GD compared with control subjects (P < 0.001 and P < 0.05). Monoclonal M22 TSAbs stimulated cAMP (HEK cells) in a dose-dependent manner. M22 (P = 0.0082), bovine TSH (P = 0.0028), and sera of hyperthyroid patients with GD (P < 0.05) increased superoxide-specific 2-hydroxyethidium levels in HEK-293 TSHR cells after 48-hour incubation vs control subjects. In contrast, triiodothyronine (T3) did not affect reactive oxygen species (ROS) production. In primary thyrocytes, the 4-HNE marker was higher in patients with GD vs control subjects at 6 and 48 hours (P = 0.02 and P = 0.04, respectively). Further, after 48-hour incubation of HEK-293 TSHR cells with patient sera, 4-HNE was higher in patients with untreated GD compared with control subjects (P < 0.05).

CONCLUSIONS

Monoclonal M22 and polyclonal serum TSAbs augment ROS generation and/or induce lipid peroxidation.

Thyroid Stimulating Hormone Receptor Antibodies in Thyroid Eye Disease-Methodology and Clinical Applications

BACKGROUND

Thyroid stimulating hormone receptor antibodies (TSHR-Ab) cause autoimmune hyperthyroidism and are prevalent in patients with related thyroid eye disease (TED).

PURPOSE

To provide a historical perspective on TSHR-Ab and to present evidence-based recommendations for clinical contemporary use.

METHODS

The authors review the recent literature pertaining to TSHR-Ab in patients with TED and describe the various immunoassays currently used for detecting TSHR-Ab and their clinical applications.

RESULTS

We provide a historical summary and description of the various methods used to detect TSHR-Ab, foremost, the functional TSHR-Ab. Increasing experimental and clinical data demonstrate the clinical usefulness of cell-based bioassays for measurements of functional TSHR-Ab in the diagnosis and management of patients with autoimmune TED and in the characterization of patients with autoimmune-induced hyperthyroidism and hypothyroidism. Thyroid stimulating hormone receptor antibodies, especially the functional stimulating antibodies, are sensitive, specific, and reproducible biomarkers for patients with autoimmune TED and correlate well with clinical disease activity and clinical severity. Unlike competitive-binding assays, bioassays have the advantage of indicating not only the presence of antibodies but also their functional activity and potency.

CONCLUSIONS

Measurement of TSHR-Ab (especially stimulating antibodies) is a clinically useful tool for the management of patients with TED.

Graves' disease in children

R1 The diagnosis of Graves' disease in children is based on detecting a suppression of serum TSH concentrations and the presence of anti-TSH receptor antibodies. 1/+++. R2 Thyroid ultrasound is unnecessary for diagnosis, but can be useful for assessing the size and homogeneity of the goiter. 2/+. R3. Thyroid scintigraphy is not required for the diagnosis of Graves' disease. 1/+++. R4. The measurement of T4L and T3L levels is not necessary for the diagnosis of Graves' disease in children but can be useful for the management and assessment of prognosis. 1/++. R5. In the absence of TSH receptor autoantibodies, the possibility of genetically inherited hyperthyroidism must be considered. 1/++. R6. Drug therapy is the primary line of treatment for children and consists of imidazole, carbimazole or thiamazole, with an initial dosage of 0.4 to 0.8mg/kg/day (0.3 to 0.6mg/kg/day for thiamazole) depending on the initial severity, up to maximum of 30mg. 1/++. R7. Propylthiouracil is contraindicated for children with Grave's disease. 1/+++. R8. Before starting treatment, it may be useful to perform a CBC in order to assess the degree of neutropenia caused by hyperthyroidism. It is not necessary to perform systematic CBCs during follow-up. 2/+. R9. An emergency CBC should be performed if symptoms include fever or angina. If neutrophil counts are <1000/mm³, synthetic antithyroid therapy should be discontinued or decreased and may be permanently contraindicated in severe (<500) and persistent neutropenia. Otherwise treatment may be resumed. 1/++. R10. Transaminases levels should be measured before initiating treatment. Systematic monitoring of liver function is not consensually validated. 2/+. R11. In cases of jaundice, digestive disorders or pruritus, measuring liver enzymes (AST, ALT), total and conjugated bilirubin and alkaline phosphatases is indicated. 1/++. R12. Patients and parents should be informed of the possible side effects of antithyroid agents. 1/+. R13. Therapeutic education of parents and children is important in ensuring the best possible treatment compliance. 2/++. R14. Given the specificities involved in the treatment of Graves' disease in children, medical care should be provided by a specialist accustomed to treating endocrinopathies in pediatric patients. 2/+. R15. Depending on patient age, the severity of the disease at diagnosis and the persistence of anti-TSH receptor antibodies, the initial course of treatment must take place over an extended period of 3 to 6 years. R16.The anticipated success rates of medical treatment (50% of patients in remission following several years of treatment) should be explained to the family and the child. The possibility that radical treatment may be required in case of failure or intolerance of medical treatment should also be discussed. 1/++. R17.In females with Graves' disease, it is important to explain that they must undergo an assessment by an endocrinologist before planning future pregnancies, from the start of pregnancy and during the course of pregnancy. This is true in all female patients, even those in remission after medical treatment, or those who have undergone radical treatment. R18.Indications for a radical treatment can arise in cases of: 1/+: contraindication to antithyroid agents; poorly controlled hyperthyroidism due to lack of compliance; relapse despite prolonged medical treatment; a request made by the family and child for personal reasons. R19.Surgery is the radical method of treatment used in children under 5 years of age, or in cases of very large, nodular, or compressive goiters. 2/++. R20. The surgeon's experience in dealing with thyroidectomies in children is likely to be the most significant determining factor in limiting the morbidity of the procedure (alongside any collaboration between a pediatric surgeon and an adult surgeon). 1/++. R21 When radical treatment is indicated, I-131 treatment may be discussed after 5 years (but more often after puberty), if the goiter is not too large. Experience from monitoring Graves' disease in North American children is reassuring. 1/++.

Diagnosis and management of hyperthyroidism from prenatal life to adolescence

Hyperthyroidism in children is a rare heterogeneous syndrome characterized by excessive thyroid hormone production. Its manifestations differ according to disease severity. For all forms of hyperthyroidism, treatment aims to restore a euthyroid state, enabling the child to demonstrate appropriate metabolism, growth, and neurocognitive development. Graves' disease is the most frequent cause of hyperthyroidism in children. Treatment modalities include antithyroid drugs, with the advantage that prolonged treatment for several years can be followed by freedom from medical intervention in about 40-50% of cases. It may also be treated with radioactive iodine or, less frequently, thyroidectomy, these more radical treatments both necessitating subsequent lifelong levothyroxine treatment. Particular care is required in the management of pregnant women with Graves' disease. Fetal and neonatal forms of hyperthyroidism are transient and rare, but nevertheless serious. Here, we provide an overview of the best approach to hyperthyroidism diagnosis and management, from fetal development to adolescence.

2018 European Thyroid Association Guideline for the Management of Graves' Hyperthyroidism

Graves' disease (GD) is a systemic autoimmune disorder characterized by the infiltration of thyroid antigen-specific T cells into thyroid-stimulating hormone receptor (TSH-R)-expressing tissues. Stimulatory autoantibodies (Ab) in GD activate the TSH-R leading to thyroid hyperplasia and unregulated thyroid hormone production and secretion. Diagnosis of GD is straightforward in a patient with biochemically confirmed thyrotoxicosis, positive TSH-R-Ab, a hypervascular and hypoechoic thyroid gland (ultrasound), and associated orbitopathy. In GD, measurement of TSH-R-Ab is recommended for an accurate diagnosis/differential diagnosis, prior to stopping antithyroid drug (ATD) treatment and during pregnancy. Graves' hyperthyroidism is treated by decreasing thyroid hormone synthesis with the use of ATD, or by reducing the amount of thyroid tissue with radioactive iodine (RAI) treatment or total thyroidectomy. Patients with newly diagnosed Graves' hyperthyroidism are usually medically treated for 12-18 months with methimazole (MMI) as the preferred drug. In children with GD, a 24- to 36-month course of MMI is recommended. Patients with persistently high TSH-R-Ab at 12-18 months can continue MMI treatment, repeating the TSH-R-Ab measurement after an additional 12 months, or opt for therapy with RAI or thyroidectomy. Women treated with MMI should be switched to propylthiouracil when planning pregnancy and during the first trimester of pregnancy. If a patient relapses after completing a course of ATD, definitive treatment is recommended; however, continued long-term low-dose MMI can be considered. Thyroidectomy should be performed by an experienced high-volume thyroid surgeon. RAI is contraindicated in Graves' patients with active/severe orbitopathy, and steroid prophylaxis is warranted in Graves' patients with mild/active orbitopathy receiving RAI.

Celiac Disease and Glandular Autoimmunity

Celiac disease is a small intestinal inflammatory disease with autoimmune features that is triggered and maintained by the ingestion of the storage proteins (gluten) of wheat, barley, and rye. Prevalence of celiac disease is increased in patients with mono- and/or polyglandular autoimmunity and their relatives. We have reviewed the current and pertinent literature that addresses the close association between celiac disease and endocrine autoimmunity. The close relationship between celiac disease and glandular autoimmunity can be largely explained by sharing of a common genetic background. Further, between 10 and 30% of patients with celiac disease are thyroid and/or type 1 diabetes antibody positive, while around 5–7% of patients with autoimmune thyroid disease, type 1 diabetes, and/or polyglandular autoimmunity are IgA anti-tissue transglutaminase antibody positive. While a gluten free diet does not reverse glandular autoimmunity, its early institution may delay or even prevent its first manifestation. In conclusion, this brief review highlighting the close association between celiac disease and both monoglandular and polyglandular autoimmunity, aims to underline the need for prospective studies to establish whether an early diagnosis of celiac disease and a prompt gluten-free diet may positively impact the evolution and manifestation of glandular autoimmunity.

Treatment of Graves' disease in children: The Portuguese experience

INTRODUCTION

Graves' disease (GD) is an autoimmune thyroid disease, common in adults but rare in children. The best therapeutic approach remains controversial.

OBJECTIVES

To ascertain the current treatment of pediatric GD in Portugal and to assess the clinical and biochemical factors that determine definitive/long-term remission after treatment with antithyroid drugs (ATDs).

PATIENTS AND METHODS

A retrospective analysis of data about pediatric GD treatment collected from a nationwide survey conducted by the Portuguese Society of Pediatric Endocrinology and Diabetology from May to August 2013. Population was categorized based on sex, age, use of ATDs, dosage, treatment duration, adverse reactions, thyrotropin receptor-stimulating antibody (TRAB) titer, remission and remission/relapse rates, and definitive treatment, and divided into group A (with ongoing treatment) and group B (with treatment stopped). Group B was subdivided into 'Remission', 'Remission+relapse' and 'No remission' subgroups based on the course of disease. The same parameters were compared between both groups.

RESULTS

Survey response rate was 77%; 152 subjects, 116 female, mean age at diagnosis 11.23±3.46 years. They all started treatment with ATDs, 70.4% with thiamazole, with a mean treatment duration of 32.38±28.29 months, and 5.9% had adverse effects. Remission rate was 32.6%. Lower age at diagnosis correlated with higher remission rates. Treatment duration was longer when propylthiouracil was used. Initial TRAB titer was significantly higher in the 'No remission' group. Surgery and radioiodine were used as second-line treatments.

CONCLUSION

Our study results were similar to those reported in the literature. Age and TRAB titer were identified as potential clinical and laboratory determinants of remission. Based on risk/benefit analysis, it was concluded that treatment should be individualized based on age, accessibility to treatments, and physician's experience.

The Influence of Juvenile Graves' Ophthalmopathy on Graves' Disease Course

Purpose

To investigate juvenile Graves' ophthalmopathy (GO) signs and compare Graves' disease (GD) course in patients with or without GO.

Patients and Methods

There were analyzed data (visual acuity, proptosis, palpebral fissure measurements, clinical activity score (CAS), and the course of GD) of 67 children who have been newly diagnosed with GD. 26.9% of patients with GD had signs of ophthalmopathy (GO+), and 73.1% were without ophthalmopathy (GO−).

Results

Upper eyelid retraction (72.3%), proptosis (66.7%), and soft tissue changes (27.8−38.9%) were in GO+ patients. The palpebral fissure, CAS, and proptosis values were greater in the GO+ group than in the GO− group (p < 0.001). GD course in GO+ patients was longer than that in GO− patients (p < 0.001). The duration of the first remission was longer in GO− than in GO+ patients (p < 0.001). The duration of first remission was longer than one year for 61.2% in GO− and 33.3% in GO+ patients (p < 0.02).

Conclusion

The common manifestations of juvenile GO patients were upper eyelid retraction, proptosis, and soft tissue involvement. The study demonstrates that pediatric patients with GO are more likely to have a severe course of autoimmune thyroid disease.

Performance and Specificity of 6 Immunoassays for TSH Receptor Antibodies: A Multicenter Study

BACKGROUND

The measurement of TSH receptor (TSHR) antibodies is warranted for diagnosis of Graves' disease (GD).

OBJECTIVE

The performance, detection sensitivity, and specificity of 6 TSHR immunoassays were compared.

METHODS

Two bioassays and 4 binding assays (Kronus, Immulite, Kryptor, Dynex) were compared in a dilution study performed in patients with autoimmune thyroid disease. Both bioassays were compared to 2 binding assays using stimulatory (M22) and blocking (K1-70) monoclonal antibody (MAb) mixtures.

RESULTS

Thirty samples from stimulatory (TSAb)-positive/blocking (TBAb)-negative patients with GD were diluted serially and measured in all assays. Samples were positive until dilution 1:2,187 in the TSAb bioassay, 1:81 in the Immulite (p < 0.002 vs. bioassay) and Kronus ELISA (p = 0.039) assays, and 1:27 in the Kryptor and Dynex ELISA (p < 0.001 vs. bioassay). Ten samples from TBAb-positive/TSAb-negative patients with GD or Hashimoto's thyroiditis were positive in all binding assays. None of the binding assays differentiated between TSAb and TBAb. Mixtures of 100% K1-70 (200 ng/mL), 80% K1-70 + 20% M22, 60% K1-70 + 40% M22, 40% K1-70 + 60% M22, 20% K1-70 + 80% M22, and 100% M22 (20 ng/mL) tested positive in both Immulite (26.4, 20.2, 15.2, 10.5, 6.3, 2.00 IU/L) and Kronus assays (27.1, 23.3, 19.3, 12.0, 5.7, 2.2 IU/L). These MAb mixtures were tested in the TBAb bioassay and showed 82, 61, 24 (negative), -26 (negative), -77 (negative), and -95% (negative) inhibition, respectively.

CONCLUSIONS

The sample dilution study showed higher detection sensitivity for the TSAb bioassay, and the antibody mixture study demonstrated exclusive specificity of the bioassays over all automated and ELISA binding assays.