Bioassays for TSH Receptor Antibodies: Quo Vadis?

Clinical evaluation of an automated TSI bridge immunoassay in the diagnosis of Graves' disease and its relationship to the degree of hyperthyroidism

BACKGROUND

The rapid and accurate detection of thyroid-stimulating hormone (TSH) receptor antibodies has always been an urgent need for the clinical diagnosis and management of Graves' disease (GD). We aimed to evaluate the use of an automated thyroid-stimulating immunoglobulin (TSI) bridge immunoassay in the diagnosis of GD and to analyze the relationship between TSI and the degree of hyperthyroidism.

METHODS

A total of 227 new-onset GD patients, 29 Hashimoto thyroiditis, 43 non-autoimmune thyroid diseases and 37 euthyroid controls were consecutively recruited. All participants accepted the measurement of their serum thyroid function and thyroid-associated antibodies, including TSI being measured by an Immulite 2000 bridge immunoassay and TSH receptor autoantibodies (TRAb) being measured by a third-generation Roche electrochemiluminescence immunoassay. The quantitative consistency between the TSI and TRAb detection methods was analyzed by using Passing-Bablok regression and Bland-Altman plots. The diagnostic performance for GD was assessed by receiver operating characteristic (ROC) curve analysis.

RESULTS

Among 227 GD patients (174 females and 53 males, with a mean age of 39 years), the quantitative TSI was positively correlated with TRAb (r = 0.8099). According to the cut-off values proposed by the manufacturers (TSI: 0.55 IU/L, TRAb: 1.75 IU/L), the positive rates of TSI and TRAb in new-onset GD patients were 96.92% and 95.15%, respectively. Both TSI and TRAb levels positively correlated with FT₄ levels (TSI: r = 0.243, TRAb: r = 0.317; all P < 0.001) and FT₃ levels (TSI: r = 0.288, TRAb: r = 0.360; all P < 0.001) in new-onset GD patients. The ROC analysis showed that the optimal TSI cut-off value was 0.577 IU/L for GD diagnosis in this Chinese population, with a sensitivity of 96.92% and a specificity of 97.25%, respectively. The optimal TRAb cut-off value of was 1.38 IU/L, with a sensitivity of 96.92% and a specificity of 99.08%. There were no significant differences between the cut-off values obtained through the ROC analysis and those provided by the manufacturer for both TSI and TRAb when calculating their sensitivity and specificity in diagnosing GD. Among the 8 newly diagnosed GD cases with discordant qualitative antibody results, TSI was more likely than TRAb to match the clinical diagnosis of GD (6 TSI-positive vs. 2 TRAb-positive patients).

CONCLUSION

The automated TSI bridge immunoassay was positively correlated with thyroxine levels in new-onset GD patients and was more likely to be consistent with the clinical diagnosis of GD than with that of TRAb. The positive Immulite 2000 TSI cut-off value of 0.577 IU/L for GD diagnosis in the Chinese population were close to the value recommended by the manufacturer.

Clinical efficacy of thyroid-stimulating immunoglobulin detection for diagnosing Graves' disease and predictors of responsiveness to methimazole

BACKGROUND

As thyroid-stimulating immunoglobulins (TSI) are a sign of Graves' disease (GD), measuring TSI titers is becoming increasingly important for GD diagnosis. This study evaluated the diagnostic accuracy of a new fully automated TSI immunoassay (Immulite™ TSI assay) in GD patients and compared it to the third generation thyroid-stimulating hormone receptor antibody (TRAb) electrochemiluminescence assay (Elecsys Anti-TSHR assay). Additionally, clinical characteristics associated with responsiveness to methimazole in patients with newly diagnosed GD were preliminarily explored.

METHODS

This study involved 324 subjects, comprising patients with untreated GD (GD-UT), Graves' ophthalmopathy (GO) patients, GD patients who had been treated for > 12 months (GD-T), autoimmune thyroiditis (AIT) patients, and healthy subjects (HS). The Immulite™ TSI and Elecsys Anti-TSHR assay were performed on all samples. According to their responsiveness to methimazole, the GD-UT patients were divided into rapid and slow responder groups, and their clinical characteristics were compared.

RESULTS

A receiver operating characteristic (ROC) curve analysis of GD-UT patients showed that the optimal TSI cut-off value was 0.57 IU/L. Logistic regression revealed that age and initial FT4 and TSI levels in the middle-dose methimazole group were related to a rapid response, while the initial FT4 level, but not TSI, in the high-dose group was also associated with a rapid response.

CONCLUSIONS

The clinical diagnostic performance of the Immulite™ TSI assay for diagnosing GD was comparable to that of the Elecsys Anti-TSHR assay. The initial FT4 and TSI levels can be used as predictors of the responsiveness to methimazole in patients with newly diagnosed GD.

Correlation between serum anti-TSH receptor autoantibodies (TRAbs) and the clinical feature of Graves' orbitopathy

BACKGROUND

Graves' orbitopathy (GO) is the most common extrathyroidal manifestation of Graves' disease (GD). Several studies support the involvement of TSH receptor autoantibodies (TRAbs) in the pathogenesis of GO, and a correlation between GO features and TRAbs has been reported, but not confirmed by all studies. Thus, we conducted a cross-sectional investigation to determine whether there is a correlation between TRAbs and the clinical features of GO in an initial phase of the eye disease.

METHODS

Ninety consecutive patients with untreated GO (67 women and 23 men, age 48.9 ± 12.6 years) were included. Patients who had received treatments other than anti-thyroid drugs for hyperthyroidism or lubricants for GO were excluded. All patients underwent an endocrinological and ophthalmological evaluation, the latter including exophthalmometry, measurement of eyelid width, clinical activity score (CAS), visual acuity, assessment of diplopia, and NOSPECS score. TRAb levels were measured by a third-generation competitive immunoassay.

RESULTS

There was a statistically significant, direct correlation between serum TRAb levels and CAS by linear regression analysis (R = 0.278, P = 0.007). The correlation was confirmed by a multiple regression analysis (R = 0.285; P = 0.006) including age and FT3 levels, which also correlated with CAS. There were no relationships between TRAbs and exophthalmometry, eyelid aperture, degree of diplopia, visual acuity, and NOSPECS score.

CONCLUSIONS

The levels of TRAb in subjects with a recent-onset, untreated GO are directly correlated with the clinical activity of the disease, confirming a possible role of these antibodies in the pathogenesis of GO.

Predictive Factors for Changes in Quality of Life after Steroid Treatment for Active Moderate-to-Severe Graves' Orbitopathy: A Prospective Trial

OBJECTIVES

To investigate the predictive factors for changes in the quality of life (GO-QoL) of patients with Graves' orbitopathy (GO) prior to and after specific treatment.

METHODS

A prospective follow-up study was conducted at an academic tertiary referral orbital center with a joint thyroid-eye clinic on 100 consecutive patients with GO. Before and after the standard 12-week course of weekly intravenous methylprednisolone (cumulative dose 4.5 g), the GO-QoL questionnaire provided by the European Group on Graves' Orbitopathy (EUGOGO) was completed. Endocrine and ophthalmic assessments were performed at each visit.

RESULTS

All patients were biochemically euthyroid and untreated for GO at baseline and presented with active and moderate-to-severe disease. Both GO-QoL subscales (visual functioning [VF] and appearance [AP]) significantly increased after immunosuppressive therapy and showed a sustained improvement for 6 months. At baseline, demographic variables (sex, age, and smoking) influenced QoL in the stepwise linear regression (p < 0.01, adjusted R ² = 0.24 for VF and p < 0.01, adjusted R ² = 0.21 for AP). In contrast, 6 months after treatment, the improved QoL was now exclusively associated with ophthalmic parameters (p < 0.01, adjusted R ² = 0.47 for VF; p < 0.01, adjusted R ² = 0.23 for AP).

CONCLUSIONS

Predictive factors for GO-QoL differed not only between the 2 subscales but also before and after the first treatment of GO.

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.

Thyrotropin receptor antibody immunoassays may not be reliable in confirming diagnosis of Painless Thyroiditis

BACKGROUND

Scintigraphy using 99mTc-pertechnetate (TS) is the diagnostic test to differentiate thyroiditis following Graves' disease (GD) from painless thyroiditis (PT). However, TS may be contraindicated or unavailable.

OBJECTIVE

We compared the diagnostic effectiveness of two TSH receptor antibody (TRAb) immunoassays in untreated PT, already confirmed by qualitative and quantitative(99m) Tc-pertechnetate thyroid uptake (TCTU).

METHOD

TRAb assay and TS were performed in suspected PT patients. All 67 subjects (27 males) with confirmed diagnosis of PT based on qualitative (subjective) low uptake and quantitative uptake below 0.4% (Normal TcTU: 0.4-4%). During the period of study, we used two 2^nd generation TRAb assays.

RESULT

Mean age, TSH, free T4 and TcTU were 40.5± 12.7 years, 0.066±0.089 mIU/L, 2.46±2.18 ng/mL and 0.188±0.0503% respectively. Fifteen (22.39%) of our PT patients were TRAb positive. Sensitivity, specificity, accuracy, PPV and NPV of TRAb in predicting thyroiditis were 81%, 75%, 78.2%, 83.6% and 74.4% in Assay 1. The same parameters were 74%, 64%, 71.2%, 76.8% and 62.7% respectively in TRAb Assay 2. However, ROC curve did not reveal any difference between the two assays.

CONCLUSION

Negative TRAb value does not reliably distinguish PT from mild GD, in situations where TS is contraindicated or unavailable.

Systemic safety analysis of mycophenolate in Graves' orbitopathy

PURPOSE

The dual antiproliferative mechanism of mycophenolate appears to be beneficial in Graves' orbitopathy (GO).

METHODS

Safety data from the two published mycophenolate trials and the original database of the European Group on Graves' Orbitopathy (EUGOGO) trial were systematically analyzed. Treatment efficacy stratified by individual visual parameters of activity and severity were compared.

RESULTS

A total of 129 adverse events (AE) involving 50 patients (29.4%) were noted among all mycophenolate-treated patients. Mycophenolate sodium plus intravenous glucocorticoid (MPS + GC) group of the EUGOGO trial recorded significantly more AE (55.4% versus 4.6% of patients affected) and serious adverse events (SAE) (12.5% versus 0%) than mycophenolate mofetil (MMF) group of the Chinese trial. None of those SAE was side effect (SE). Most SE in MPS + GC group were mild. Gastrointestinal disorders, infection and liver dysfunction affected 8.8%, 7.1% and 1.2% of all mycophenolate-treated patients (versus 5.4%, 5.4% and 1.2% of all patients on GC monotherapy, respectively). MPS + GC did not significantly increase the risk of infection or liver dysfunction when compared to GC monotherapy. No cytopenia, serious infection or treatment-related mortality was reported. The much higher AE rates of mycophenolate trials in other autoimmune diseases or transplantations suggested that major mycophenolate toxicities were mostly dose- and duration dependent. Mycophenolate, either as monotherapy or as combination, achieved better overall response than GC monotherapy.

CONCLUSION

The risk-benefit ratio of low-dose mycophenolate treatment in active moderate-to-severe GO is highly favorable given its reassuring safety profile with low rate of mild-to-moderate SE and promising efficacy.

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.

Diagnostic testing for Graves' or non-Graves' hyperthyroidism: A comparison of two thyrotropin receptor antibody immunoassays with thyroid scintigraphy and ultrasonography

OBJECTIVE

Graves' disease (GD) is the most common cause of hyperthyroidism. In many cases, when the aetiological diagnosis of GD is not evident based on the clinical evaluation and thyroid function testing, it may become challenging to distinguish Graves' hyperthyroidism from other forms of thyrotoxicosis. The current study was primarly carried out to compare the diagnostic effectiveness of two TSH receptor antibody immunoassays (IMAs), ultrasonography and thyroid scintigraphy in hyperthyroidism scenario.

METHODS

We retrospectively analysed consecutive patients with newly diagnosed and untreated thyrotoxicosis who underwent thyroid functional tests, both TRAb and TSI measurements, thyroid scintigraphy and ultrasonography. TRAb assessment was carried out by Kryptor^® compact PLUS, while TSI by Immulite^® . Echo pattern 3 corresponded to 'thyroid inferno', and the final diagnosis of GD vs non-Graves' hyperthyroidism was made according to the thyroid scan (qualitative scintigraphy). Receiver operating characteristic (ROC) curves were drawn using the final diagnosis as reference. Clinical sensitivity and specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated for all the tests.

RESULTS

A total of 124 untreated hyperthyroid patients were included in our study (GD, n = 86 vs non-Graves' hyperthyroidism, n = 38). ROC curves showed that the optimal cut-off values associated with the highest diagnostic sensitivity and specificity was 0.7 IU/L for TRAb Kryptor^® (93 [85.4-97.4] and 86.8 [71.9-95.5]) and 0.1 IU/L for TSI Immulite^® (94.2 [86.9-98.1] and 84.2 [68.7-93.9]), respectively. For the echo pattern 3, we found a good sensitivity (92.1%) and a high PPV (95.2%) but a quite low specificity value (69.8%) and a relative low NPV (57.5%). For thyroid scintigraphy, the TcTU cut-off value of 1.3% corresponded to the best limit for sensitivity and specificity in our patients (95.3 [88.5-98.7] and 96.4 [81.6-99.4]). The Passing-Bablok regression equation and the Bland-Altman test showed a great degree of correlation and agreement existed between TRAb Kryptor^® and Immulite^® TSI results.

CONCLUSIONS

Thyroid scintigraphy remains the most accurate method to differentiate causes of thyrotoxicosis. However, TRAb assays can be alternatively adopted in this setting, limiting the use of thyroid scintigraphy (TcTU evaluation) to TRAb-negative patients. Thyoid US is less accurate than both TRAb/TSI and thyroid scintigraphy, but the 'thyroid inferno' pattern provides a high PPV for GD.

Serum Ratio of Free Triiodothyronine to Thyroid-Stimulating Hormone: A Novel Index for Distinguishing Graves' Disease From Autoimmune Thyroiditis

OBJECTIVE

Graves' disease (GD) and autoimmune thyroiditis (AIT) are two major causes of thyrotoxicosis that require correct diagnosis to plan appropriate treatment. The objectives of this study were to evaluate the usefulness of thyroid-related parameters for distinguishing GD from AIT and identify a novel index for differential diagnosis of thyrotoxicosis.

DESIGN

This retrospective study was performed using electronic medical records in Peking University People's Hospital (Beijing, China).

METHODS

In total, 650 patients with GD and 155 patients with AIT from December 2015 to October 2019 were included in cohort 1. Furthermore, 133 patients with GD and 14 patients with AIT from December 2019 to August 2020 were included in cohort 2 for validation of the novel index identified in cohort 1. All patients were of Chinese ethnicity and were newly diagnosed with either GD or AIT. Thyroid-related clinical information was collected before intervention by reviewing the patients' electronic medical records. Receiver operating characteristic curve analysis was used to identify the optimal cutoff for distinguishing GD from AIT.

RESULTS

In cohort 1, thyroid-stimulating hormone (TSH) receptor antibody was identified as the best indicator for distinguishing GD from AIT. The area under the receiver operating characteristic curve was 0.99(95% confidence interval: 0.98-0.99, p<0.0001)and the optimal cutoff was 0.84 IU/l (98% sensitivity and 99% specificity). The free triiodothyronine (FT3)/TSH ratio (FT3/TSH) was the second -best for distinguishing GD from AIT, the area under the receiver operating characteristic curve of FT3/TSH was 0.86 (95% confidence interval: 0.84-0.88, p<0.0001); its optimal cutoff was 1.99 pmol/mIU (79% sensitivity and 80% specificity). Its effectiveness was confirmed in cohort 2 (81% sensitivity and 100% specificity).

CONCLUSIONS

The FT3/TSH ratio is a new useful index for differential diagnosis of thyrotoxicosis, especially when combined with TRAb.

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.

Clinical utility of TSH receptor antibody levels in Graves' orbitopathy: a comparison of two TSH receptor antibody immunoassays

Introduction

Thyroid stimulating hormone (TSH) receptor antibodies (TRAB) play a role in the development of Graves’ orbitopathy (GO), and measurements of the TRAB level may be helpful in monitoring GO treatment.

Aim of the study

To assess the correlation of TRAB levels measured with two different assays: third-generation TRAB assay (TRAB Cobas) and novel Immulite assay (TRAB Immulite), in patients with moderate-to-severe GO treated with intravenous glucocorticoid pulse therapy (ivGCs).

Material and methods

Forty patients with active, moderate-to-severe GO underwent clinical and laboratory evaluation before, in the middle, and after ivGCs therapy. The correlation of TRAB levels with GO signs was evaluated. Laboratory and clinical findings were compared according to the response to ivGCs. TRAB concentration was measured with Immulite TSI assay and with Elecsys IMA.

Results

All patients were TRAB positive in both assays at the beginning of the treatment. The decrease of both TRAB Immulite and Cobas levels in serum during ivGCs was statistically significant. We observed strong correlation between both TRAB levels before and after ivGCs. There was no statistically significant difference in antibody levels between patients with good response and no response to the treatment. We did not find any correlation between antibody levels and GO features before the therapy, but measurements during ivGCs showed comparable correlation of both TRAB levels with GO activity.

Conclusions

We found similarity between Immulite assay and third-generation TRAB assay in the assessment of patients with GO treated with ivGCs. Both TRAB levels showed comparable correlation with GO activity during ivGCs therapy.

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.

Unexpected cause of fever in a patient with untreated HIV

We report a case of a 27-year-old man with a history of untreated HIV who presented with fever, rash and leg cramps. Initial suspicion was high for an infectious process; however, after an exhaustive evaluation, thyrotoxicosis was revealed as the aetiology of his symptoms. Recent intravenous contrast administration complicated his workup to determine the exact cause of hyperthyroidism. Differentiation between spontaneously resolving thyroiditis and autonomous hyperfunction was paramount in the setting of existing neutropenia and the need for judicious use of antithyroid therapy. The inability to enlist a nuclear scan in the setting of recent iodinated contrast administration prompted alternative testing, including thyroid antibodies and thyroid ultrasound. In this case, we will discuss the diagnostic challenges of thyrotoxicosis in a complex patient, the sequelae of iodine contrast administration, effects of iodine on the thyroid and the predictive value of other available tests.

Nivolumab-induced thyroid dysfunction lacking antithyroid antibody is frequently evoked in Japanese patients with malignant melanoma

BACKGROUND

Nivolumab, an anti-programmed cell death-1 monoclonal antibody, has improved the survival of patients with malignant melanoma. Despite its efficacy, nivolumab inconsistently induces thyroid dysfunction as an immune-related adverse event (irAE). This study aimed to evaluate nivolumab-induced thyroid dysfunction to determine the risks and mechanisms of thyroid irAEs.

METHODS

After excluding 10 patients, data of 24 patients with malignant melanoma (aged 17-85 years; 54% female) were retrospectively analyzed.

RESULTS

Thyroid irAEs were observed in seven patients (29%). Three patients had hypothyroidism after preceding transient thyrotoxicosis, and the other four patients had hypothyroidism without thyrotoxicosis. Levothyroxine-Na replacement was required in three patients. Antithyroid antibody (ATA) titer was elevated in one of four assessable patients. The average (±SD) time to onset of thyroid irAE was 33.6 (±21.9) weeks. The administration period of nivolumab was longer in patients with thyroid irAEs than in those without thyroid irAEs (P < 0.01). There were no significant differences between patients with and without thyroid irAEs regarding age, sex, tumor stage, response to nivolumab therapy, baseline thyroid function, antithyroid peroxidase antibody (anti-TPO Ab) and antithyroglobulin antibody (anti-Tg Ab).

CONCLUSIONS

Thyroid dysfunction was a common irAE of nivolumab in malignant melanoma. Neither anti-TPO Ab nor anti-Tg Ab was associated with the risk for nivolumab-induced thyroid dysfunction. A conventional ATA-independent mechanism might be involved in thyroid irAEs. Further studies are required to clarify the mechanism and identify the predictive factors of thyroid irAEs.

Graves' hyperthyroidism in pregnancy: a clinical review

Background

Graves’ hyperthyroidism affects 0.2% of pregnant women. Establishing the correct diagnosis and effectively managing Graves’ hyperthyroidism in pregnancy remains a challenge for physicians.

Main

The goal of this paper is to review the diagnosis and management of Graves’ hyperthyroidism in pregnancy. The paper will discuss preconception counseling, etiologies of hyperthyroidism, thyroid function testing, pregnancy-related complications, maternal management, including thyroid storm, anti-thyroid drugs and the complications for mother and fetus, fetal and neonatal thyroid function, neonatal management, and maternal post-partum management.

Conclusion

Establishing the diagnosis of Graves’ hyperthyroidism early, maintaining euthyroidism, and achieving a serum total T4 in the upper limit of normal throughout pregnancy is key to reducing the risk of maternal, fetal, and newborn complications. The key to a successful pregnancy begins with preconception counseling.

Diagnostic accuracy of a new fluoroenzyme immunoassay for the detection of TSH receptor autoantibodies in Graves' disease

Purpose

Thyrotropin receptor (TSHR) autoantibodies (TRAbs) are a hallmark of Graves’ disease (GD). The aim of this study was to evaluate the diagnostic accuracy of a new third generation automatic fluorescence enzyme immunoassay for TRAb measurement in GD, in comparison with two current IMAs.

Methods

Sera of 439 subjects (57 patients with untreated GD, 34 with treated GD, 15 with GD and Graves’ orbitopathy, 52 with multinodular non-toxic goiter, 86 with Hashimoto’s thyroiditis, 20 with toxic adenoma or toxic multinodular goiter, 55 with non-thyroid autoimmune diseases and 120 normal controls) were tested for TRAbs with the ELiA^™ anti-TSH-R assay (ThermoFischer Scientific, Uppsala, Sweden), the TRAK^™ RIA, Brahms (Thermo Scientific, Hennigsdorf, Germany) and the Immulite^™ TSI assay (Siemens Healthcare, Llanberis, UK).

Results

Sensitivity and specificity of the ELiA™ anti-TSH-R assay, TRAK™ RIA and Immulite™ TSI assay were 94.7% and 99.6, 100 and 98.2%, 100 and 98.2%, respectively. Spearman’s coefficient and Passing-Bablok regression showed a satisfactory correlation between EliA™ and TRAK™ [rho: 0.925; 95% CI: 0.883-0-953. Intercept: − 0.875 (95% CI: − 2.411 to 0.194); slope: 1.086 (95% CI: 0.941 to 1.248)], and between ELiA^™ and TSI^™ [rho: 0.947; 95% CI: 0.912 0.969. intercept: 1.085 (95% CI: 0.665 to 2.116); slope 1.315 (95% CI:1.116 to 1.700)].

Conclusions

The diagnostic performance of ELiA^™-TSH-R assay is comparable to that of some current TRAb assays. It may be adopted into clinical practice for the differential diagnosis of hyperthyroidism, to screen for transient hyperthyroidism, and to monitor disease activity and treatment effects.

Stimulating TSH receptor autoantibodies immunoassay: analytical evaluation and clinical performance in Graves’ disease

Background

Thyroid-stimulating hormone (TSH) receptor (TSHR) autoantibodies (TRAbs) are a heterogeneous group of antibodies (Abs) with different functionalities. Among all TRAbs, only the stimulating ones (S-TRAbs) are considered as the pathogenetic marker of Graves’ disease (GD). To date, the methods available for TRAbs testing are based on immunoassays (IMAs) which detect total serum TRAbs or bioassays which are not suitable in clinical practice, even though they discern Abs functionality. The aim of our work was to evaluate the analytical and clinical performance of a very recent IMA (Immulite TSI method), supposed to test only the serum concentration of S-TRAbs, in comparison with a current method for total TRAbs (Roche/Elecsys IMA).

Methods

We evaluated serum samples of 145 subjects: 46 with untreated (GD), 36 with chronic autoimmune thyroiditis, 3 with atrophic thyroiditis, 10 with multinodular non-toxic goiter and 50 healthy subjects.

Results

The method showed an optimal analytical sensitivity and high precision levels (LoB: 0.04 UI/L, LoD:0.07 UI/L, LoQ:0.14 UI/L, intra-assay CV: 4.2–5.9%, inter-assay: 4.5–7.2%). By receiver operating characteristics curve analysis, we obtained a value of 0.57 (sensitivity: 98.0%, specificity: 99.9%) as the best cut-off to distinguish GD, apart from four cases. Passing Bablok regression and Bland Altman analysis pointed out a good correlation and agreement with Roche method (R2 = 0.98, slope = 1.03, bias = −2.70).

Conclusions

The new method presents very promising analytical characteristics and could be adopted in clinical practice for GD diagnosis. Moreover, the test allows to accurately detect very low values of analyte with a further clinical utility in detecting earlier possible relapses.

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

BACKGROUND

Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2011, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid disease in women during pregnancy, preconception, and the postpartum period.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. The guideline task force had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid disease in pregnancy include recommendations regarding the interpretation of thyroid function tests in pregnancy, iodine nutrition, thyroid autoantibodies and pregnancy complications, thyroid considerations in infertile women, hypothyroidism in pregnancy, thyrotoxicosis in pregnancy, thyroid nodules and cancer in pregnant women, fetal and neonatal considerations, thyroid disease and lactation, screening for thyroid dysfunction in pregnancy, and directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid disease in pregnant and postpartum women. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with these disorders.

Evaluation of the first fully automated immunoassay method for the measurement of stimulating TSH receptor autoantibodies in Graves' disease

BACKGROUND

Thyroid stimulating hormone (TSH) receptor autoantibodies (TRAb) are pathogenetic and diagnostic hallmarks of Graves' disease (GD). Three varieties of TRAb have been described: stimulating (S-TRAb), blocking (B-TRAb), and apoptotic (A-TRAb) autoantibodies. Very recently, the first immunoassay method (Immulite TSI assay, Siemens Healthcare Diagnostics) declared to measure serum S-TRAb concentration, has been made available in an automated commercial platform. The aim of the study was to evaluate the ability of this new test to identify patients suffering from GD, in comparison with two current IMA methods for total TSH receptor autoantibodies (T-TRAb) measurement.

METHODS

Sera of 383 subjects [72 patients with untreated GD, 55 patients with autoimmune thyroiditis (AIT), 36 patients with multinodular non-toxic goiter, 100 patients with other non-thyroid autoimmune diseases (NTAD) and 120 healthy subjects (HS)] were evaluated.

RESULTS

The threshold obtained by receiver operating characteristic (ROC) analysis was 0.54 IU/L, very similar to that proposed by the manufacturer (0.55 IU/L). Thyroid-stimulating immunoglobulins (TSI) were positive in all GD patients and negative in all but three controls (clinical sensitivity and specificity of 100% and 98.7%, respectively). Passing and Bablok regression analysis and Bland-Altman plot showed an acceptable agreement between TSI Immulite assay and other two immunoassay methods (Cobas/Elecsys, Roche and TRAK RIA, BRAHMS Thermo Scientific).

CONCLUSIONS

The diagnostic performance of fully automated Immulite TSI assay in GD patients is at least comparable to that of current TRAb immunoassays (IMAs) suggesting the possibility of including such assay in rapid and cost-saving diagnostic and monitoring algorithms. However, our results do not provide full evidence that this assay is specific for S-TRAb only, and future studies comparing Immulite TSI assay to stimulating activity are required.

2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis

BACKGROUND

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This document describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

METHODS

The American Thyroid Association (ATA) previously cosponsored guidelines for the management of thyrotoxicosis that were published in 2011. Considerable new literature has been published since then, and the ATA felt updated evidence-based guidelines were needed. The association assembled a task force of expert clinicians who authored this report. They examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to update the 2011 text and recommendations. The strength of the recommendations and the quality of evidence supporting them were rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' orbitopathy; and management of other miscellaneous causes of thyrotoxicosis. New paradigms since publication of the 2011 guidelines are presented for the evaluation of the etiology of thyrotoxicosis, the management of Graves' hyperthyroidism with antithyroid drugs, the management of pregnant hyperthyroid patients, and the preparation of patients for thyroid surgery. The sections on less common causes of thyrotoxicosis have been expanded.

CONCLUSIONS

One hundred twenty-four evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Oxidative Stress and Upregulation of Antioxidant Proteins, Including Adiponectin, in Extraocular Muscular Cells, Orbital Adipocytes, and Thyrocytes in Graves' Disease Associated with Orbitopathy

BACKGROUND

Graves' orbitopathy (GO) is the main extrathyroidal manifestation associated with Graves' disease (GD). It is characterized by reduced eye motility due to an increased volume of orbital fat and/or of extraocular muscles (EOMs) infiltrated by fibrosis and adipose tissue. The pathogenetic mechanisms leading to fibrosis and adipogenesis are mainly based on the interaction between orbital fibroblasts and immune cells (lymphocytes and mast cells) infiltrating the GO EOMs.

METHODS

Analysis of the morphological status, oxidative stress (OS), and antioxidant defenses in the orbital muscular cells and adipocytes in GO patients compared with controls was conducted.

RESULTS

Both cell types are affected by OS, as shown by the increased expression of 4-hydroxynonenal, which leads to apoptosis in muscular cells. However, the EOMs and the adipocytes possess antioxidant defenses (peroxiredoxin 5 and catalase) against the OS, which are also upregulated in thyrocytes in GD. The expression of adiponectin (ApN) and proliferator-activated receptor gamma (PPARγ) is also increased in GO muscular cells and adipocytes. OS and antioxidant proteins expression are correlated to the level of blood antithyrotropin receptor antibodies (TSHR-Ab).

CONCLUSION

Even when TSHR-Ab level is normalized, OS and antioxidant protein expression is high in EOM muscular cells and adipocytes in GO compared with controls. This justifies a supplementation with antioxidants in active as well as chronic GO patients. Orbital muscular cells are also the sources of PPARγ and ApN, which have direct or indirect local protective effects against OS. Modulation of these proteins could be considered as a future therapeutic approach for GO.