Assays for thyroid-stimulating antibodies and thyrotropin-binding inhibitory immunoglobulins in children with Graves' disease

The risk factors for Graves' ophthalmopathy

PURPOSE

This review aimed to provide an overview of current research into the risk factors for Graves' ophthalmopathy (GO).

METHODS

To find information about the risk factors for GO, the research database PubMed was searched and relevant articles were obtained to extract information about risk factors.

RESULTS

Smoking has been widely accepted as an important risk factor and cigarette smoking cessation has been shown to improve the outcome and decrease the onset of GO. Radioactive iodine on the thyroid may induce hyperthyroidism and increase the occurrence of GO. Selenium deficiency is a risk factor for GO and the supplementation of selenium has been an adjuvant therapy. Decreasing stressful life events (SLE) may help improve GO. Imbalance in intestinal flora is essential to GO, with Yersinia enterocolitica and Escherichia coli both increased in the digestive tract of the individual with GO. In addition, controlling serum cholesterol may help improve GO since adipogenesis is an important pathological change in its pathogenesis. Considering the correlation between Graves' disease and GO, maintaining normal thyroid function hormone level is the first-line therapeutic strategy to prevent progression of GO. An increase in antibodies such as TSHR and IGF-1R is the main predictor of GO. Besides, gender and gene polymorphism are also risk factors towards GO.

CONCLUSIONS

Risk factors for GO arise from five sources: physical and chemical environment, social-psychological environment, biological environment, the human organism, and genetic codes. Risk factors within these categories may interact with each other and their mechanisms in promoting the development of GO are complex. Research into risk factors for GO may promote emerging fields related to GO such as control of autoantibodies and intestinal microbiota.

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.

Thyroid autoantibodies in adults with acquired binocular diplopia of unknown origin

Patients with acquired adult-onset strabismus mainly present with binocular diplopia. Although cranial nerve palsies are reportedly the most common cause of binocular diplopia in adults, thyroid disease can also cause diplopia. In patients with thyroid-associated ophthalmopathy, upper lid retraction and proptosis are the most common initial findings, but diplopia could be the first manifestation. So far, there has been little information on the diagnostic value of thyroid autoantibodies in patients with strabismus. Therefore, we examined adults with acquired binocular diplopia from 2008 to 2016 and evaluated the presence of thyroid autoantibodies and the relationship between thyroid autoantibody status and clinical characteristics in adults with acquired binocular diplopia. Thyroid autoantibody tests were performed for all patients, unless other causes of diplopia were identified. Fifty one (39%) of 132 patients were positive for thyroid autoantibodies. In the thyroid autoantibody-positive (TAb+) group, microsomal autoantibodies, thyroid-stimulating hormone receptor antibodies, thyroglobulin antibodies, and thyroid-stimulating antibodies were observed in 30, 27, 12, and 7 patients, respectively. The vertical deviation and grade of duction limitation were greater in the TAb+ group. The presence of ocular torsion was 15.5% and 39.5% in the TAb- and TAb+ groups, respectively. Thyroid autoantibody evaluation may be helpful in adults with idiopathic acquired binocular diplopia.

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.

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.

An update on thyroid-associated ophthalmopathy in children and adolescents

BACKGROUND

Risk of developing thyroid-associated ophthalmopathy (TAO) in children and adolescents is similar or may be even slightly higher than in adults. The aim of this article is to review and summarize current knowledge regarding diagnostic and therapeutic measures in pediatric TAO.

CONTENT

MEDLINE and EMBASE papers were searched using the terms 'pediatric Graves' ophthalmopathy' 'pediatric Graves' orbitopathy', 'thyroid-associated ophthalmopathy in childhood and adolescence' from the year 1970 to December 2015.

SUMMARY

TAO usually accompanies hyperthyreosis in Graves' disease, but may also occur in patients with hypothyreosis due to chronic lymphocytic thyroiditis (Hashimoto's disease) or in euthyroid patients. Current information regarding epidemiology, pathogenesis, symptoms and treatment of TAO in children and adolescents is presented. The course of the disease is usually mild, eye disturbances often regress after restoring euthyroidism and a 'wait and see' policy is appropriate in the majority of patients. In rare cases, sight-threatening complications [dysthyroid optic neuropathy (DON) or corneal breakdown] may develop and immediate surgical intervention might become necessary.

OUTLOOK

Close cooperation between pediatric endocrinologists and opthalmologists is extremely important to ensure best care and quality of life in patients with thyroid gland dysfunction. Further investigations on pathogenesis and course of TAO in children and adolescents should be performed for better management of this disease in this group of patients.

Predictive Factors of Development of Graves' Ophthalmopathy for Patients with Juvenile Graves' Disease

Background. Due to low incidence of Graves' ophthalmopathy (GO) among children, the manifestation is poorly analyzed, posing a risk to late identification of insidious disease. Purposes. To identify predictive factors that may influence the development of GO in pediatric and young patients with Graves' disease (GD). Methods. A cross-sectional study of patients newly diagnosed with pediatric or juvenile GD during 2002-2012 was conducted at the Hospital of Lithuanian University of Health Sciences. Ocular evaluation was based on European Group on Graves' Orbitopathy survey. The ocular manifestations were analyzed in relation to demographic, environmental, and clinical factors. Results. In total, 130 patients with juvenile GD were included; 29.2% had GO. Median age at GD onset was 17 yrs (IQR 4-29). Main symptoms of GO were eyelids retraction (73.7%), proptosis (65.8%), injection of conjunctiva (42.1%), and eyeball motility disturbance (21.1%). Major significant and independent risk factors for GO development were high initial concentration of FT4 (OR = 5.963), TTHAb (OR = 6.358), stress (OR = 6.030), and smoking (OR = 7.098). Conclusion. The major factors that could influence GO development were smoking, stress, and increased levels of initial TRAb, FT4. Slight proptosis, retraction of eyelids, and conjunctive injection were found as predominant ophthalmological symptoms in juvenile GO.

The treatment of Graves' disease in children and adolescents

Graves' disease (GD) accounts for 10%-15% of thyroid disorders in children and adolescents. The use of antithyroid drugs as the initial treatment option in GD is well accepted. An average two years remission is achieved in about 30% of children treated with antithyroid drugs. However, the optimal treatment duration and the predictive marker of remission after antithyroid drug therapy are still controversial. Additionally, (131)I therapy and surgery are considered the option for treatment in children and adolescents with GD. We review the treatment options for pediatric GD and the possible determinants of remission and relapse on antithyroid drug treatment in children and adolescents.

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

CONTEXT AND OBJECTIVE

The incidence of TSH receptor (TSHR) stimulating autoantibodies (TSAbs) in pediatric Graves' disease (GD) is controversial. This large, multicenter study evaluated the clinical relevance of TSAbs in children with GD both with Graves' orbitopathy (GO) and without orbital disease.

DESIGN

We conducted a cross-sectional retrospective study.

SETTING

Sera were collected in seven American and European academic referral centers and evaluated in a central laboratory. PATIENTS AND SAMPLES: A total of 422 serum samples from 157 children with GD, 101 control individuals with other thyroid and nonthyroid autoimmune diseases, and 50 healthy children were studied.

MAIN OUTCOME MEASURES

TSAbs were measured using a novel, chimeric TSHR bioassay and a cAMP response element-dependent luciferase. TSH binding-inhibitory Ig (TBII) and parameters of thyroid function were also determined.

RESULTS

In 82 untreated children with GD, sensitivity, specificity, and positive and negative predictive values for TSAb and TBII were: 100 and 92.68% (P = .031), 100 and 100%, 100 and 100%, and 100 and 96.15%, respectively. TSAb and TBII were present in 147 (94%) and 138 (87.9%) of the 157 children with GD (P < .039), respectively; and in 247 (94%) and 233 (89%) of the 263 samples from this group (P < .0075), respectively. In children with GD and GO, TSAb and TBII were noted in 100 and 96% (P < .001), respectively. Hyperthyroid children with GD and GO showed markedly higher TSAb levels compared to those with thyroidal GD only (P < .0001). No significant differences were noted for TBII between the two groups. After a 3-year (median) medical treatment, the decrease of TSAb levels was 69% in GD vs 20% in GD and GO (P < .001). All 31 samples of euthyroid children with GO were TSAb positive; in contrast, only 24 were TBII positive (P = .016). All children with Hashimoto's thyroiditis, nonautoimmune hyperthyroidism, type 1 diabetes, and juvenile arthritis and the healthy controls were TSAb and TBII negative.

CONCLUSIONS

Serum TSAb level is a sensitive, specific, and reproducible biomarker for pediatric GD and correlates well with disease severity and extrathyroidal manifestations.

Thyroid peroxidase antibody positivity and triiodothyronine levels are associated with pediatric Graves' ophthalmopathy

BACKGROUND

Graves' ophthalmopathy (GO) occurs commonly in children with Graves' disease (GD). However, there are limited studies on the clinical manifestations and thyroid autoantibodies in pediatric GO. The aim of this study was to investigate the prevalence and risk factors of GO in childhood GD.

METHODS

Clinical and biochemical data from children and adolescents with GD were retrospectively reviewed. Eighty patients under 19 years of age were included in the present study. We compared the clinical and biochemical differences between patients with and without GO.

RESULTS

Thirty-nine percent of the patients had GO, and 81% of the GO patients were females. Of these, two patients showed unilateral GO. Triiodothyronine (T3) levels were higher in GO patients than in those without GO. Anti-thyroglobulin antibody and thyroid stimulating hormone receptor antibody titers were not significantly different between the two groups. Anti-thyroid peroxidase antibody (TPO Ab) positivity was 68% in the patients with GO and only 47% in the patients without GO. In multivariate regression analysis, high T3 levels and TPO Ab positivity were related to the presence of GO.

CONCLUSION

In children and adolescents with GD, TPO Ab positivity and high T3 levels could act as predictive factors for the presence of GO.

Approach to the pediatric patient with Graves' disease: when is definitive therapy warranted?

Pediatric Graves' disease accounts for 10-15% of thyroid disorders in patients less than 18 yr of age. The onset of symptoms may be insidious and subsequently associated with a delay in diagnosis. Decreased concentration and poor school performance are frequent complaints and can be quite frustrating for the patient and family. Severe ophthalmopathy is uncommon. The diagnosis is established by the findings of an increased heart rate and goiter in the setting of a suppressed TSH and elevated T(3) and/or T(4). The majority of pediatric patients are initially placed on antithyroid medications and maintained on these medications for prolonged periods of time in hopes of achieving remission. Unfortunately, for many children and adolescents remission is unattainable, ultimately occurring in only 15-30% of patients. Several recent studies have suggested that the age of the patient, the degree of thyrotoxicosis at diagnosis, the initial response to therapy, and the level of TSH receptor antibodies serve as reasonable predictors of remission and relapse. However, a consensus on the utility of these markers has not been reached. The present clinical case describes an adolescent with Graves' disease and highlights the negative impact that prolonged medical therapy can have on quality of life and school performance; it reviews pertinent data on the diagnosis, comorbidities, and treatment options; and it identifies gaps in knowledge for when definitive therapy should be pursued. The case serves as a reminder that earlier discussion and decision for definitive therapy should be more commonplace in caring for our pediatric patients with Graves' disease.

Intermethod Variability in TSH-Receptor Antibody Measurement: Implication for the Diagnosis of Graves Disease and for the Follow-Up of Graves Ophthalmopathy

Background: We compared the analytical and clinical performance of 3 porcine thyroid receptor antibody (TRAb) methods (1 second- and 2 new third-generation systems) with the conventional TRAb assay based on the human recombinant TSH receptor (hTRAK).

Patients and Methods: We obtained sera from 86 patients with untreated Graves disease (GD) and 71 healthy controls. We measured TRAb concentrations by radioreceptor assay using the hTRAK (Brahms) or the porcine TSH receptor (pRRA) from Beckman-Coulter, by electrochemiluminescence immunoassay (ECLIA) with the Elecsys/Cobas (Roche), and by ELISA using the Medizym TRAb clone (Medipan).

Results: Between-run assay imprecision was ≤10% and ≤7.6% for hTRAK and ECLIA, but reached 14% and 14.9% for ELISA and pRRA, respectively. Maximal specificity and sensitivity close to 100% were obtained for hTRAK, ECLIA, and ELISA. pRRA failed to detect positive TRAbs in 5 GD patients. Although calibrated against the same reference standard 90/672, the assays displayed a high intermethod variability. The results were significantly higher by ECLIA and lower by ELISA and pRRA compared with hTRAK. Patients with ophthalmopathy had higher TRAb results by ELISA and pRRA than those without eye disease.

Conclusions: Second- and third-generation TRAb assays had similar diagnostic sensitivities in the diagnostic evaluation of GD. Despite the use of the same reference standard for calibration, high intermethod variability in TRAb assay results was seen in untreated GD patients. Assay harmonization is necessary for correct interpretation in the follow-up of Graves ophthalmopathy.

Predicting the likelihood of remission in children with Graves' disease: a prospective, multicenter study

OBJECTIVE

The optimal treatment for Graves' disease in children is controversial. Antithyroid medications are often used initially, but many children eventually require alternative therapies. We evaluated predictors of remission after 2 years of antithyroid medication use.

METHODS

We prospectively studied children who had Graves' disease and were treated with antithyroid medications. We compared children who achieved remission after 2 years with those who had persistent disease to determine which variables were associated with remission; multiple logistic regression and binary recursive partitioning analyses were used to evaluate interactions among predictive variables.

RESULTS

Of 51 children who completed the study, 15 (29%) achieved remission. Children who achieved remission had lower thyroid hormone concentrations at presentation than those with persistent disease (free thyroxine: 6.17 +/- 3.10 vs 9.86 +/- 7.54 ng/dL; total triiodothyronine: 431 +/- 175 vs 561 +/- 225 ng/dL). Children who achieved remission were also more likely to be euthyroid within 3 months of initiating propylthiouracil (82% vs 29%). Binary recursive partitioning analysis identified rapid achievement of euthyroid status after initiation of propylthiouracil, lower initial triiodothyronine, and older age as significant predictors of remission. CONCLUSIONS; Thyroid hormone concentrations at diagnosis, age, and initial response to propylthiouracil can be used to stratify patients according to the likelihood of remission after 2 years of antithyroid medication use. These data provide a useful guide for clinical decision-making regarding Graves' disease in children.

Anti-thyroid-stimulating hormone receptor antibodies determined by second-generation assay

BACKGROUND

The aim of our study was to determine the frequency of anti-thyroid-stimulating hormone (TSH) receptor antibodies (TRAb) in Tunisian patients with Graves' disease (GD) and to compare the validity of TRAb to that of thyroperoxidase (TPO-Ab) and thyroglobulin antibodies (TG-Ab).

METHODS

ELISA was used to determine the frequency of TRAb, TPO-Ab and TG-Ab in sera of 190 patients with GD. Patients were divided into four groups: those with untreated active GD (group A, n=71), those receiving treatment with anti-thyroid drugs (group B, n=85), those in relapse (group C, n=15) and those in remission (group D, n=19). Sera of 100 healthy blood donors served as controls.

RESULTS

The sensitivity of TRAb for the diagnosis of GD (95.8%) was significantly higher than that of TPO-Ab (73.2%) and TG-Ab (42.2%) (p=0.0005 and p<10(-7), respectively). The positive rate for TRAb was lower in group B than in group A (70.6% and 95.8%, respectively; p=0.0001). The levels of TRAb were significantly higher in group A than in group B (mean 30.1 and 14.2 IU/L, respectively; p=0.006).

CONCLUSIONS

TRAb, but neither TPO-Ab nor TG-Ab, is valuable in the diagnosis and management of patients with GD.