Disappearance of thyrotropin-blocking antibodies and spontaneous recovery from hypothyroidism in autoimmune thyroiditis

A follow-up study on factors affecting the recovery of patients with hypothyroidism in different selenium environments

BACKGROUND

Hypothyroidism is a major manifestation of autoimmune thyroid diseases (AITD). We previously reported that a low selenium (Se) status was linked to an elevated prevalence of thyroid diseases. We hypothesized that Se status may also influence the restoration of thyroid function. Thus, this study aimed to investigate the factors affecting the recovery of thyroid function in patients with (sub-)clinical hypothyroidism, with a specific focus on Se status.

METHODS

We conducted a 6-year prospective cohort study comparing two counties with different Se concentrations. Demographic and disease data were collected from 1,190 individuals (549 Se-adequate and 641 Se-deficient) who completed a follow-up study in 2019. In addition, urinary iodine (I) levels, thyroid function, and serum and nail Se levels were measured. Logistic regression was used to investigate the relationship between Se deficiency and recovery of thyroid function.

RESULTS

Sex and smoking status was similar between the two counties studied. Thyroid function recovery rate was significantly higher in Se-deficient counties (46.0% vs. 30.6%, P = 0.008). In the multivariate analysis, our results show that female sex (odds ratio [OR] (95% confidence interval [CI]) = 1.875 (1.080-3.257), P = 0.026] and increasing age [OR (95%CI) = 1.028(1.007-1.049), P = 0.009] were associated with the recovery rate. Additionally, our study revealed that while Se status was significant in the univariate analysis, this association appeared to disappear in the multivariate analysis.

CONCLUSIONS

Female sex and increasing age have unfavorable effects on the recovery of thyroid function in patients over 30 years of age with (sub-) clinical hypothyroidism.

Genetic and Chemical Controls of Sperm Fate and Spermatocyte Dedifferentiation via PUF-8 and MPK-1 in Caenorhabditis elegans

Using the nematode C. elegans germline as a model system, we previously reported that PUF-8 (a PUF RNA-binding protein) and LIP-1 (a dual-specificity phosphatase) repress sperm fate at 20 °C and the dedifferentiation of spermatocytes into mitotic cells (termed "spermatocyte dedifferentiation") at 25 °C. Thus, double mutants lacking both PUF-8 and LIP-1 produce excess sperm at 20 °C, and their spermatocytes return to mitotically dividing cells via dedifferentiation at 25 °C, resulting in germline tumors. To gain insight into the molecular competence for spermatocyte dedifferentiation, we compared the germline phenotypes of three mutant strains that produce excess sperm-fem-3(q20gf), puf-8(q725); fem-3(q20gf), and puf-8(q725); lip-1(zh15). Spermatocyte dedifferentiation was not observed in fem-3(q20gf) mutants, but it was more severe in puf-8(q725); lip-1(zh15) than in puf-8(q725); fem-3(q20gf) mutants. These results suggest that MPK-1 (the C. elegans ERK1/2 MAPK ortholog) activation in the absence of PUF-8 is required to promote spermatocyte dedifferentiation. This idea was confirmed using Resveratrol (RSV), a potential activator of MPK-1 and ERK1/2 in C. elegans and human cells, respectively. Notably, spermatocyte dedifferentiation was significantly enhanced by RSV treatment in the absence of PUF-8, and its effect was blocked by mpk-1 RNAi. We, therefore, conclude that PUF-8 and MPK-1 are essential regulators for spermatocyte dedifferentiation and tumorigenesis. Since these regulators are broadly conserved, we suggest that similar regulatory circuitry may control cellular dedifferentiation and tumorigenesis in other organisms, including humans.

Thyroid autoantibodies

Thyroid-stimulating hormone (TSH) receptor antibody (TSH-R-Ab or TRAb) testing plays a pivotal role in arriving at the aetiological diagnosis in patients with thyrotoxicosis. A positive test establishes the diagnosis of Graves' disease (GD) while a negative result in conjunction with imaging studies supports other possible aetiologies. In patients with GD, TRAb levels at diagnosis and at the time of withdrawal of antithyroid drugs can identify patients who are unlikely to achieve remission and guide clinical management decisions. We provide an algorithm that incorporates TRAb in the decision-making process for the management of thyrotoxicosis. The utility of TRAb in predicting the risk of fetal and neonatal thyroid dysfunction is established and widely accepted in guidelines. TRAb may also help in the diagnosis of Graves' orbitopathy, especially in euthyroid or hypothyroid patients and its role in guiding its management is evolving as a useful adjunct to the clinical parameters used in making therapeutic decisions.Anti-thyroid peroxidase antibodies (TPOAb) and anti-thyroglobulin antibodies (TgAb) indicate thyroid autoimmunity. The most common use of TPOAb is to identify patients at a higher risk of progression to treatment-requiring hypothyroidism. They also aid the diagnosis of immune thyroiditis and Hashimoto's encephalopathy. Thyroglobulin measurement is used to help guide differentiated thyroid cancer treatment. TgAb is used as an accompanying test with thyroglobulin measurement as its presence can interfere with the thyroglobulin assay. A negative TgAb result reduces the likelihood of, but does not exclude, interference with thyroglobulin assay.

Graves’ Ophthalmopathy in the Setting of Primary Hypothyroidism

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

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

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

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

TSH-receptor autoantibodies in patients with chronic thyroiditis and hypothyroidism

OBJECTIVES

The reported prevalence of TSH-receptor (TSHR) autoantibodies (TRAb) in patients with chronic thyroiditis (CT) range from 0 to 48%. The objective was to study the prevalence of TRAb in patients with CT and hypothyroidism and to correlate it with gender, age, thyroid dimensions, TSH levels, and autoimmune diseases.

METHODS

The study comprised 245 patients with CT and hypothyroidism (median age 42 years, 193 females, 52 males) and 123 Italian healthy subjects matched for sex and age as controls. TRAb were tested with ELISA using a >2.5 IU/L cut off for positivity. TSHR blocking (TBAb) and TSHR stimulating autoantibodies (TSAb) were measured in 12 TRAb-positive patients using bioassays with Chinese hamster ovary (CHO) cells expressing wild-type or R255D-mutated TSHR.

RESULTS

TRAb positivity was found in 32/245 (13.1%) patients and significantly correlated (p<0.05) with TSH levels. TRAb positivity was significantly higher in males vs. females (p=0.034), in females 16-45 years of age vs. >45 years of age (p<0.05) and in patients with reduced vs. normal/increased thyroid dimensions (p<0.05). Linear regression analysis showed a correlation between TRAb concentrations with age (p<0.05) and TRAb concentrations with TSH (p<0.01). In bioassay with TSHR-R255D all 12 patients tested were TBAb-positive while 33% were also TSAb-positive suggesting the presence of a mixture of TRAbs with different biological activities in some patients.

CONCLUSIONS

TRAb have been found in patients with CT and hypothyroidism. A mixture of TBAb and TSAb was found in some patients and this may contribute to the pathogenesis of thyroid dysfunction during the course of the disease.

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

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

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

The effect of radioiodine treatment on the characteristics of TRAb in Graves' disease

BACKGROUND

Graves' disease (GD) is one of the most common autoimmune thyroid diseases (AITDs) in humans, and thyrotropin receptor antibody (TRAb) is a characterized autoantibody in GD. The use of radioactive iodine therapy (RAI) for GD treatment is increasing.

OBJECTIVES

We studied the biological properties of TRAb and evaluated the effect of RAI therapy on TRAb in GD patients.

METHODS

In total, 225 patients (22 onset GD patients without ¹³¹I therapy, 203 GD patients treated with ¹³¹I therapy) and 20 healthy individuals as normal controls were included in this study. Clinical assessments were performed, and we examined in vitro the biological properties of TRAb in the 22 onset GD patients and 20 controls as well as 84 GD patients with ¹³¹I therapy.

RESULTS

Serum TRAb and thyroid peroxidase antibody (TPOAb) levels increased in the initial year of RAI treatment, and both antibodies decreased gradually after one year. After 5 years from radioiodine treatment, TRAb and TPOAb levels decreased in 88% and 65% of GD patients, respectively. The proportion of patients positive for thyroid-stimulatory antibody (TSAb) was significantly higher in the 7-12-month group, and thyroid-blocking antibody (TBAb) levels were elevated after one year in half of the patients who received ¹³¹I treatment.

CONCLUSIONS

Treatment of GD patients with radioiodine increased TPOAb and TRAb (their main biological properties were TSAbs) within the first year after therapy, and the main biological properties of elevated TRAb were TBAbs after 1 year.

Clinical Outcomes After Discontinuation of Thyroid Hormone Replacement: A Systematic Review and Meta-Analysis

Background: Levothyroxine (LT4) is one of the most commonly prescribed medications. Although considered a life-long replacement therapy, LT4 therapy can be discontinued for some patients. This study aims at: (i) reviewing the evidence on clinical outcomes of patients undergoing thyroid hormone replacement discontinuation, (ii) identifying the predictors of successful discontinuation, and (iii) systematically appraising frameworks used for deprescribing thyroid hormone. Methods: We searched multiple bibliographic databases, including Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus, from inception to February 2020 for studies in which thyroid hormone replacement was discontinued. Clinical outcomes assessed included: proportion of patients that remained euthyroid or needed to restart thyroid hormone replacement after discontinuation and frequency of clinical symptoms of hypothyroidism and adverse effects. We also evaluated predictors for discontinuation and deprescribing frameworks. Reviewers (F.J.K.T., N.B., N.M.S.O., S.M.) evaluated studies for inclusion, extracted data, and assessed methodological quality independently and in duplicate. Results: Seventeen observational studies at moderate to high risk of bias met inclusion criteria, including a total of 1103 patients (86% women) with an age range of 2-81 years. Approximately a third of patients undergoing thyroid hormone discontinuation remained euthyroid at follow-up (37.2%, 95% confidence interval [CI 24.2-50.1%], I² 97.5%). Subgroup analysis showed that patients with a previous diagnosis of overt hypothyroidism (OH) were less likely to remain euthyroid (11.8% [CI 0.4-23.2%], I² 90.3%) than patients with a prior diagnosis of subclinical hypothyroidism (SCH) (35.6% [CI 8.2-62.9%], I² 94.0%). No study followed a framework for systematically deprescribing LT4. Conclusions: Low-quality evidence suggests that up to a third of patients remained euthyroid after thyroid hormone discontinuation, with a higher proportion of patients with an initial diagnosis of SCH remaining euthyroid than patients with an initial diagnosis of OH. A deprescribing framework focusing on adequate selection of patients for deprescribing LT4 and a systematic process is warranted to guide clinicians in re-evaluating the need for LT4 in their patients.

Investigation of TSH receptor blocking antibodies in childhood-onset atrophic autoimmune thyroiditis

Atrophic autoimmune thyroiditis (AAT) is a type of autoimmune hypothyroidism without goiter. TSH receptor-blocking antibodies (TSBAb) are involved in its etiology in adults. Reportedly, this disease is extremely rare in children. In this study, we aimed to investigate the prevalence of TSBAb during AAT onset in children using a commercially available cell-based bioassay TSAb kit. We conducted a multicenter retrospective observational study. We collected data of patients with AAT who were < 15 yr old, enrolled in a collaborative research group, and diagnosed since July 2003. AAT was defined as acquired autoimmune hypothyroidism without thyroid enlargement. Eighteen patients (including 15 females) whose TSH receptor antibody (TRAb) or TSBAb levels were measured within a year from the initial visit were included. The median age at diagnosis was 9.3 years, and the estimated time between onset and diagnosis was 2.6 yr. The positive rate for either TSBAb or TRAb was 38.8% (95% confidence interval: 18.3–59.5%). There were no significant differences in age, the estimated time between onset and diagnosis, and FT4 levels at diagnosis between the TSBAb-positive and -negative groups. Unlike previous reports, we showed that the prevalence of TSBAb-positivity in childhood-onset AATs is not rare, as in adults.

Clinical Course of Euthyroid Subjects With Positive TSH Receptor Antibody: How Often Does Graves' Disease Develop?

Background

Thyroid stimulating hormone receptor antibody (TRAb) is detected in the serum of patients with Graves’ disease (GD). This study aims to investigate the prevalence of euthyroid individuals showing positive results for TRAb and to clarify the clinical course of thyroid function and TRAb levels in these subjects.

Objective

Subjects were female patients who newly visited our hospital for a screening test prior to fertility treatment and showed normal thyroid function and volume without nodules between 2014 and 2017. After excluding subjects with a history of thyroid disease, 5,622 subjects were analyzed.

Results

Forty-seven of the 5,622 subjects showed positive results for TRAb (reference range, <2.0 IU/L) at the initial visit. Median initial TRAb was 2.9 IU/L (range, 2.0-14.7 IU/L) and median follow-up was 18.3 months (range, 0-66.5 months). Six of the 47 subjects (12.8%) developed GD and median duration until development was 6.6 months (range, 1.2-13.2 months). Median TRAb values initially and at diagnosis of GD for those 6 patients were 3.7 IU/L (range, 2.7-5.1 IU/L) and 7.2 IU/L (range 3.6-21.4 IU/L), respectively. TRAb results turned negative for 20 of the 47 subjects but remained positive despite normal thyroid function in 13 of the 47 subjects.

Conclusion

GD developed over time in 12.8% of euthyroid young female patients showing positive TRAb within a median of 6.6 months. A positive result for TRAb itself did not mean development of GD, so other factors must be essential for the pathogenesis of GD.

Non-Conventional Clinical Uses of TSH Receptor Antibodies: The Case of Chronic Autoimmune Thyroiditis

Anti TSH receptor antibodies (TSHrAb) are a family of antibodies with different activity, some of them stimulating thyroid function (TSAb), others with blocking properties (TBAb), it is a common finding that antibodies with different function might coexist in the same patient and can modulate the function of the thyroid. However, most of the labs routinely detect all antibodies binding to the TSH receptor (TRAb, i.e. TSH-receptor antibodies detected by binding assay without definition of functional property). Classical use of TSHr-Ab assay is in Graves' disease where they are tested for diagnostic and prognostic issues; however, they can be used in specific settings of chronic autoimmune thyroiditis (CAT) as well. Aim of the present paper is to highlight these conditions where detection of TSHr-Ab can be of clinical relevance. Prevalence of TSHrAb is different in in the 2 main form of CAT, i.e. classical Hashimoto's thyroiditis and in atrophic thyroiditis, where TBAb play a major role. Simultaneous presence of both TSAb and TBAb in the serum of the same patient might have clinical implication and cause the shift from hyperthyroidism to hypothyroidism and vice versa. Evaluation of TRAb is recommended in case of patients with Thyroid Associated Orbitopathy not associated with hyperthyroidism. At present, however, the most relevant recommendation for the use of TRAb assay is in patients with CAT secondary to a known agent; in particular, after treatment with alemtuzumab for multiple sclerosis. In conclusion, the routine use of anti-TSH receptor antibodies (either TRAb or TSAb/TBAb) assay cannot be suggested at the present for diagnosis/follow up of patients affected by CAT; there are, however, several conditions where their detection can be clinically relevant.

Clinical factors predicting the successful discontinuation of hormone replacement therapy in patients diagnosed with primary hypothyroidism

BACKGROUND

Although reversible in some patients, primary hypothyroidism is considered a permanent condition requiring lifelong hormone therapy. This study aimed to investigate the factors predicting the successful discontinuation of levothyroxine (L-T4) therapy in patients with primary hypothyroidism.

METHODS

A retrospective study was performed in primary hypothyroidism patients who met inclusion criteria: patients who maintained stable L-T4 therapy for more than 1 year, following gradual dose reduction of L-T4 based on the clinical decision (L-T4 tapering); patients receiving either no L-T4 or a fixed minimum dose for more than 1 year after L-T4 tapering. Reduction in L-T4 dosage by 12.5-50 μg within 3 months was considered as L-T4 tapering. Serum free T4, TSH, and clinical symptoms were evaluated before, during and after tapering. Logistic regression and decision tree analyses were performed to predict the successful discontinuation of L-T4.

RESULTS

Among 382 patients, 22.5% and 58.4% showed successful discontinuation (T4-Discontinued) and dose reduction (T4-Reduced) of L-T4 therapy, while other did not obtained any reduction of L-T4 dose (T4-Unchanged). The median number of tapering visit was 1.0 (range, 1.0-4.0). In T4-Discontinued group, the TSH level and the positive rate of anti-thyroperoxidase at the time of L-T4 initiation were lower, the duration of L-T4 therapy was shorter, and the maintenance dose of L-T4 at the time of tapering was lower than those in the T4-Unchanged group. In ultrasonography, normal parenchyma was preserved in the T4-Discontinued group while others showed higher rates of heterogeneous or hypoechoic parenchymal changes. Among those different characteristics, the longer duration of L-T4 therapy and the higher maintenance dose of L-T4 at the time of tapering significantly predicted the failure of discontinuation of L-T4 in multivariate analysis. A decision tree showed that patients with a duration of L-T4 therapy >4.6 years had lower success rate of discontinuation.

CONCLUSION

Shorter duration of L-T4 therapy and lower L-T4 dose at the time of tapering are the predictable factors for successful L-T4 tapering in stably maintained primary hypothyroidism patients.

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.

Hypothesis: Persistently normal TSH levels may be used to recognize patients with transient forms of hypothyroidism and to suggest treatment withdrawal

There are no text-book recommendations on when or if treatment should or could be stopped in patients with a diagnosis of hypothyroidism, and these patients usually receive lifelong thyroxine therapy (despite the fact that some of them may have forms of transient hypothyroidism that will later recover function). Since TSH fluctuations during thyroxine treatment are common and a lack of this fluctuation might be used to identify patients who no longer need thyroxine treatment, we hypothesize that by offering patients with persistently controlled TSH levels a withdrawal trial of thyroxine treatment we may identify those who no longer need life-long treatment.

Hyperthyroidism in an infant of a mother with autoimmune hypothyroidism with positive TSH receptor antibodies

BACKGROUND

Neonatal hyperthyroidism is rare, seen in infants of mothers with Graves' disease (GD), with transplacental transfer of thyroid-stimulating hormone receptor (TSHR) antibodies (TRAbs). We describe a neonate with severe hyperthyroidism due to TRAbs, born to a mother with autoimmune hypothyroidism.

CASE PRESENTATION

A baby boy born preterm at 35 weeks had irritability, tachycardia and proptosis after birth. The mother had autoimmune hypothyroidism, from age 10, with thyroxine replacement and normal thyroid function throughout her pregnancy. She had never been thyrotoxic. There was a family history of Hashimoto's thyroiditis (HT) and GD. The baby's thyroid function on day 3 demonstrated gross thyrotoxicosis, TSH<0.01 mIU/L (normal range [NR]<10 mIU/L), free thyroxine (FT4)>77 pmol/L (20-35), free triiodothyronine (FT3) 15.4 pmol/L (4.2-8.3) and TRAb 18.4 IU/L (<1.8). The mother's TRAb was 24.7 IU/L. Thyrotoxicosis required propranolol and carbimazole (CBZ). Thyroid function normalized within 10 days. The baby was weaned off medication by 7 weeks. He remains euthyroid.

CONCLUSIONS

We postulate that this mother had co-existing destructive thyroiditis and thyroid-stimulating antibodies (TSAbs) and TSHR blocking antibodies (TBAb), rendering her unable to raise a thyrotoxic response to the TSAbs but with predominant TSAb transmission to her infant. Maternal history of any thyroid disorder may increase the risk of transmission to an infant, requiring a careful clinical assessment of the neonate, with important implications for future pregnancies.

Adding carbimazole to levothyroxine increases triiodothyronine and improves outcome in patients with primary hypothyroidism: a preliminary study from Egypt

BACKGROUND

Many hypothyroid patients are not tolerant and not satisfied with levothyroxine (LT4). Older studies used large doses of both carbimazole and LT4 for Hashimoto's thyroiditis (HT), because Graves' disease (GD) and HT were considered as very closely related syndromes produced by thyroid autoimmunity.

OBJECTIVE

The aim of the study was to determine the outcome after adding small doses of carbimazole to reduced doses of LT4 for patients with primary hypothyroidism, who are unable to tolerate LT4.

METHODS

The study is a non-randomized, single arm, interventional study. It included 19 female patients diagnosed with primary hypothyroidism who could not tolerate LT4. Subjects were recruited from the outpatient clinic of AL-Azhar University Hospital in Damietta, Egypt from January to March 2015. They were divided into two groups; group 1 included 10 patients with HT and 2 patients with non-specified primary hypothyroidism, and group 2 included 7 patients with subtotal thyroidectomy for GD. All patients received carbimazole (10 mg/day) beside LT4 (25 μg thrice/week) for 10 weeks. Statistical analysis of the data was done by SPSS version 20, using paired-sample t-test, ANOVA, Chi square, and Pearson coefficient test.

RESULTS

There was significant increase in free triiodothyronine (FT3) in addition to significant improvement in depression and LT4 tolerance in the whole population. There was non-significant improvement in TSH in group 1 (p=0.053). Surprisingly, in group 2, in spite of significant increase in TSH (p=0.007) and non-significant decrease in free thyroxine (FT4), there was non-significant increase in FT3. Whether carbimazole improves the pathology of the hypothyroid gland or the peripheral deiodination of T4 to T3 (where the serum and tissue levels of the latter may be responsible for improvement of symptoms) is in need of investigation.

CONCLUSIONS

Adding carbimazole to LT4 improves FT3, LT4 tolerance, and depression in primary hypothyroid female patients. Further studies are required to determine the appropriate doses of this regimen in different cases.

CLINICAL TRIAL REGISTRATION

This study was registered at Thai Clinical Trials Registration center (http://www.clinicaltrials.in.th) with registration ID: TCTR20170123003.

FUNDING

The study received no fund or grant.

Analytical Performance and Validation of a Bioassay for Thyroid-Blocking Antibodies

BACKGROUND AND OBJECTIVE

A cell-based bioassay for the measurement of thyroid blocking autoantibodies (TBAb) has been recently reported. The analytical performance and validation of this bioassay is assessed and described.

METHODS

Chinese hamster ovary cells expressing a chimeric thyrotropin receptor were treated with bovine (b) TSH and different concentrations of an immunoglobulin G (IgG) monoclonal human TBAb (K1-70). TBAb was measured as a function of luciferase activity relative to bTSH alone and expressed as percent inhibition. Results obtained in the chimeric cell line were compared with those of a wild-type cell line. Analytical performance studies were subsequently performed with the chimeric cell line only.

RESULTS

Immunodepletion of K1-70 IgG by using a protein G-Sepharose column showed that positive percent inhibition in the TBAb bioassay was detectable from K1-70 IgG only. The limit of blank was determined to be 12.2%. The limit of detection was 14% inhibition, equivalent to 0.4 ng/mL K1-70, while the limit of quantitation was 22% (coefficient of variation [CV] 12%) equivalent to 0.625 ng/mL K1-70. The dynamic range was between 14 ± 3.7 (mean % inhibition ± standard deviation) and 101 ± 2.6, equivalent to 0.4-10 ng/mL K1-70. The linear range was between 22 ± 2.6 and 93 ± 0.6 inhibition, equivalent to 0.625-5 ng/mL K1-70. The upper limit of the 99th percent reference range was 34% inhibition. In two laboratories, CV values for the intra- and inter-assay precisions for K1-70 ranged from 2% to 12% and from 1.7% to 14.5%, respectively. For patient sera, the CV values for the intra- and inter-assay precisions ranged from 3% to 9% and from 3% to 11%, respectively. No interference was found when follicle-stimulating hormone, luteinizing hormone, and human chorionic gonadotrophin were tested in the TBAb bioassay. The median of % inhibition values in 40 TBAb positive sera from patients with autoimmune thyroid disease were 93.5 (range 25-103) and 92 (range 64-107) for the wild type and chimeric cell lines, respectively. Further, all 40 samples of patients with various non-thyroidal autoimmune diseases were TBAb negative.

CONCLUSIONS

This TBAb bioassay exhibits excellent analytical performance and high level of reproducibility.

High cut-off value of a chimeric TSH receptor (Mc4)-based bioassay may improve prediction of relapse in Graves' disease for 12 months

There are scarce reports regarding a functional prognostic value of thyroid-stimulating autoantibody (TSAb) levels using a thyroid-stimulating hormone receptor chimera (Mc4) in Graves' disease (GD) in iodine sufficient area. The aim of this study was to investigate whether Mc4-TSAb can predict GD remission/relapse after antithyroid drug (ATD) treatment and to compare Mc4-TSAb with a binding assay using M22 monoclonal antibody (M22-TRAb) in GD patients. We retrospectively reviewed the results of M22-TRAb and Mc4-TSAb in GD patients treated with ATD for 12 months. GD patients who underwent ATD treatment for at least 12 months were included. We compared the predictive values of M22-TRAb and Mc4-TSAb for GD remission and relapse. Of the 92 patients, 60 (65.2%) achieved remission and 32 (34.8%) relapsed within 12 months. In receiver operating characteristic analysis, there were no significant differences in the area under the curves (AUCs) between Mc4-TSAb [AUC=0.79 (95% CI 0.69-0.89)] and M22-TRAb [AUC=0.69 (95% CI 0.58-0.81)]. The optimal predictive cut-off values of M22-TRAb and Mc4-TSAb were 2.23 IU/L and 230%, respectively. At a high Mc4-TSAb cut-off, the better specificity of 85.0% and positive predictive value (PPV) of 69.0% were shown compared with those at the best cut-off for M22-TRAb. In conclusion, a high cut-off for an Mc4 assay may improve the predictive value of relapse with superior specificity and PPV compared with M22-TRAb in treated GD.

Nongoitrous autoimmune thyroiditis with facial palsy

We report a case of severe hypothyroidism with nongoitrous, autoimmune thyroiditis and pituitary hyperplasia in a 13-year-old boy, who presented with sudden palsy on the left side of his face. Prednisolone and antiviral medication was administered. However, the facial palsy did not improve completely. The medications were replaced with thyroxine, and the facial palsy recovered. Endocrinological testing showed severe hypothyroidism as follows: thyroid stimulating hormone (TSH) level >100 µIU/mL, T4 of 1.04 µg/dL, T3 of 0.31 ng/mL, and free T4 of 0.07 ng/dL. Level of serum antithyroid peroxidase antibodies was 1,933.39 IU/mL, and that of antithyroglobulin antibodies was 848.16 IU/mL. Level of TSH receptor antibodies was >40 IU/L. Bioassay result for TSH receptor stimulating antibodies was negative. Thyroid sonography revealed no increase in the size or vascularity of the bilateral gland. Thyroid scintigraphy with 99mTc showed decreased uptake, and magnetic resonance imaging demonstrated an enlarged pituitary gland.

Thyroid autoantibodies in pregnancy: their role, regulation and clinical relevance

Autoantibodies to thyroglobulin and thyroid peroxidase are common in the euthyroid population and are considered secondary responses and indicative of thyroid inflammation. By contrast, autoantibodies to the TSH receptor are unique to patients with Graves' disease and to some patients with Hashimoto's thyroiditis. Both types of thyroid antibodies are useful clinical markers of autoimmune thyroid disease and are profoundly influenced by the immune suppression of pregnancy and the resulting loss of such suppression in the postpartum period. Here, we review these three types of thyroid antibodies and their antigens and how they relate to pregnancy itself, obstetric and neonatal outcomes, and the postpartum.

Autosomal-dominant chronic mucocutaneous candidiasis with STAT1-mutation can be complicated with chronic active hepatitis and hypothyroidism

PURPOSE

To describe a case of autosomal-dominant (AD)-chronic mucocutaneous candidiasis (CMC) with a signal transducer and activator of transcription (STAT) 1 gene mutation, and some of the important complications of this disease such as chronic hepatitis.

METHODS

We present a 23-year-old woman with CMC, chronic active hepatitis, and hypothyroidism. Her father also had CMC. We performed several immunological analyses of blood and liver samples, and searched for gene mutations for CMC in the patient and her father.

RESULTS

We identified the heterozygous substitution c.821 G > A (p.Arg274Gln) in the STAT1 gene of both the patient and her father. The level of β-glucan induced interferon (IFN)-γ in her blood cells was significantly low. Immunoblot analysis detected serum anti-interleukin (IL)-17 F autoantibody. She was found to have increased (low-titer) antibodies related to her hypothyroidism and hepatitis. Her serum IL-18 levels fluctuated with her AST and ALT levels. Liver biopsy revealed CD68-positive cell infiltration and IL-18 expression in the sinusoidal regions. These results suggest that the chronic active hepatitis in this patient may be exacerbated by the excessive IL-18 accumulation caused by recurrent mucocutaneous fungal infection, and decreased IFN-γ production.

CONCLUSIONS

AD-CMC is known to be caused by a gain-of-function mutation of the STAT1 gene. Chronic active hepatitis is a rare complication of AD-CMC, with currently unknown pathogenesis. It seems that the clinical phenotype in this patient is modified by autoimmune mechanisms and cytokine dysregulation. AD-CMC can be complicated by various immune disorders including autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy.

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

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

Case report: rapid spontaneous recovery from severe hypothyroidism in 2 teenage girls

Background

While it is recognized that patients sometimes recover from autoimmune hypothyroidism, little is known about how rapidly this may occur.

Case reports

Two 13 year old girls had severe primary hypothyroidism (total T4 14.2 nmol/L with TSH 468 miU/L and total T4 7.7 nmol/L with TSH 183 miU/L) accompanied by goiter and positive thyroid peroxidase antibodies. There were delays in starting thyroid hormone replacement, and complete reversal of hypothyroidism was documented within 2 months in both cases. One of the girls had recurrence of severe hypothyroidism after being euthyroid for 18 months.

Review of literature

There are few published studies which have looked systematically at reversibility of acquired hypothyroidism, but one Japanese study found that recovery from autoimmune hypothyroidism may occur within weeks. Other causes of primary hypothyroidism (TSH-blocking antibodies, iodine excess, medications) seem less likely, so this probably represents rapid spontaneous reversal of autoimmune hypothyroidism.

Conclusion

Patients with severe autoimmune hypothyroidism may have spontaneous normalization of thyroid tests within weeks to months after diagnosis. This suggests that reevaluating the need for thyroid hormone replacement in selected patients with persistently normal TSH during therapy should be considered.

Natural recovery from antiglomerular basement membrane glomerulonephritis is associated with glomeruli-infiltrating CD8α+CD11c+MHC class II+ cells

BACKGROUND/AIMS

In an antiglomerular basement membrane glomerulonephritis (GN) model, GN-resistant Lewis (LEW) rats naturally recover from early glomerular inflammation (days 21-23). We have previously identified a glomeruli-infiltrating CD8α(+)CD11(high)MHC II(+) cell (GIL CD8α(+) cell) in GN-prone Wistar Kyoto (WKY) rats, which terminates glomerular inflammation through inducing T cell apoptosis prior to glomerular fibrosis at days 35-40. We investigated if GIL CD8α(+) cells were also associated with the recovery in LEW rats.

METHODS

GIL CD8α(+) cells in LEW rats were characterized; their infiltration was observed in connection with T cell apoptosis in glomeruli.

RESULTS

An influx of GIL CD8α(+) cells into inflamed glomeruli was confirmed in the immunized LEW rats at days 17-22, which was much earlier than days 28-35 in WKY rats. Notably, LEW rats had a GIL CD8α(+)CD11(high) subpopulation after day 17, while WKY rats lacked this population until after day 30. Analyses further revealed a large number of clustered apoptotic CD4(+) or CD3(+) T cells in the glomeruli during recovery (day 23) in LEW rats, as compared to day 35 (transition to fibrosis) in WKY rats. Thus, infiltration of GIL CD8α(+) cells coincided with decline of glomerular inflammation and T cell apoptosis during recovery in LEW rats. Isolated GIL CD8α(+) cells were able to infiltrate glomeruli in both WKY and LEW rats at day 20.

CONCLUSION

Our data revealed a strong association between GIL CD8a+ cells and recovery from early glomerular inflammation. It raises a possibility of involvement of GIL CD8a+ cells in the recovery.

Erythrocyte zinc concentration as an indicator to distinguish painless thyroiditis-associated transient hypothyroidism from permanent hypothyroidism

Red blood cell (RBC) zinc (Zn) concentration reflects a patient's mean thyroid hormone level over the preceding several months. The aim of this study was to examine whether RBC Zn level can be used as an indicator to distinguish painless thyroiditis-associated transient hypothyroidism (TH) from permanent hypothyroidism (PH). RBC Zn level was measured in 30 untreated PH patients with Hashimoto's thyroiditis and 7 untreated TH patients with painless thyroiditis in whom preceding transient thyrotoxicosis had been confirmed. RBC Zn concentration was significantly lower in TH patients than that in PH patients. There was a positive correlation between RBC Zn and serum TSH, and the latter was clearly lower in TH patients than that in PH patients. However, RBC Zn level was again significantly lower in TH patients than PH patients despite of the comparable serum TSH levels in both groups when RBC Zn was evaluated in patients with serum TSH levels of less than 50 mU/L. Thus TH patients could be identified with RBC Zn measurement, allowing us avoidance of unnecessarily prolonged T4 administration to them.

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

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

Clinical review about TRAb assay's history

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

Prevalence and functional significance of thyrotropin receptor blocking antibodies in children and adolescents with chronic lymphocytic thyroiditis

CONTEXT

TSH receptor (TSHR) blocking antibodies (Abs) inhibit TSH-induced thyroid growth and function in some adults with chronic lymphocytic thyroiditis (CLT), but their role in the pediatric age range is unknown.

OBJECTIVES

Our objectives were: 1) to determine the prevalence of TSHR blocking Abs in children and adolescents with CLT and 2) assess their functional significance both in vivo and in vitro.

DESIGN AND SETTING

This was a retrospective study in a referral outpatient setting.

PATIENTS

Sera from a total of 87 CLT patients and 33 controls were studied.

MAIN OUTCOME MEASURES

TSHR Abs were measured by both ELISA and bioassay.

RESULTS

Eight of 87 children and adolescents with CLT (9.2%), including one as young as 4 yr of age, had TSHR Abs in serum as measured by ELISA. The prevalence was significantly higher in individuals whose serum TSH concentration was 20 mU/liter or greater within 3 months of study than in less hypothyroid patients (eight of 45 vs. none of 42, P < 0.005). Conversely, TSHR Ab-positive patients were significantly more hypothyroid at diagnosis but only when the analysis was restricted to those with severe hypothyroidism was a decreased prevalence of goiter observed. IgG purified from TSHR Ab sera retained the TSH binding-inhibitory activity and TSHR Ab-positive sera inhibited TSH-induced stimulation of cAMP significantly more than normal.

CONCLUSIONS

TSHR-blocking Abs contribute significantly to the severity of the hypothyroidism in some children with CLT, but as compared with adults, they appear to play less of a role in determining the presence or absence of a goiter.

Thyroid volume in hypothyroidism due to autoimmune disease follows a unimodal distribution: evidence against primary thyroid atrophy and autoimmune thyroiditis being distinct diseases

CONTEXT

Primary overt autoimmune hypothyroidism is often divided into primary idiopathic hypothyroidism with thyroid atrophy (Ord's disease) and hypothyroidism with goitre (Hashimoto's disease).

OBJECTIVE

The aim of the present study was to characterize the two subtypes of disease.

DESIGN AND SETTING

This was a population-based study identifying patients newly diagnosed with overt autoimmune hypothyroidism.

PATIENTS

We prospectively identified all patients with incident overt autoimmune hypothyroidism in a Danish population cohort, and 247 patients were invited to join a comprehensive program including thyroid ultrasonography and measurements of thyroid autoantibodies. Of the 144 patients investigated (58% of all invited), 139 were compared with 556 sex-, age-, and region-matched controls from the cohort.

RESULTS

Patients had lower median (11.6 ml vs. 13.5 ml, P = 0.001) and a more dispersed distribution of thyroid volumes compared with controls (P < 0.001). Log thyroid volume showed a Gaussian distribution in both males and females with no bimodal pattern. Nearly all patients had measurable thyroid autoantibodies, but with increasing thyroid volume (quartile I, II, III, and IV), levels of circulating antibodies were higher (median thyroid peroxidase autoantibody 1540, 3122, 4686, and 7058 kU/liter; median thyroglobulin autoantibody 72, 143, 119, and 1195 kU/liter), and thyroid volume correlated negatively with echogenicity (r = -0.21, P = 0.011). Patients with the smallest volumes were biochemically more hypothyroid at diagnosis (median serum T(4) 21.0, 45.5, 45.0, and 36.7 nmol/liter; median serum TSH 81.0, 40.9, 45.4, and 55.6 mU/liter). No difference between groups was observed in prevalence of TSH receptor autoantibody (14.7, 5.6, 14.7, and 8.3%) or duration of symptoms before hypothyroidism was diagnosed.

CONCLUSIONS

In primary autoimmune hypothyroidism, thyroid volume follows a normal distribution. Cases with thyroid atrophy and goiter are only extremes within this distribution and do not represent separate disorders. However, patients with low vs. high thyroid volume differ with respects to several characteristics.

Turner's syndrome and subclinical autoimmune thyroid disease: a two-year follow-up study

Although autoimmune thyroid disease (AITD) is frequent in Turner's syndrome (TS), followup studies are scant, and there are none regarding subclinical thyroiditis. We investigated thyroid function and morphology in 17 patients with TS (mean age 14.6 years) with transient and asymptomatic variations of TSH and/or thyroid hormones. Our 2-year follow-up included measurements of TSH, free T4, T3 and TPO and Tg antibodies, ultrasound (US) (first and last evaluations) and scintigraphy (first evaluation). Thyroid volume was evaluated relative to the patients' stature. Fourteen had abnormal hormones, including four with hypothyroidism and one with hyperthyroidism, ten had positive antibodies, and all had abnormalities on US; uptake was normal in 14/16. Abnormal hormones were independent of antibodies, number of US findings, age, time of disease and volume. At the end of the follow-up, antibodies were associated with a high number of abnormal US features, particularly heterogeneous texture. Our results indicate that recurring thyroid hormone variations in TS are due to chronic AITD.

Partial recovery of adrenal function in a patient with autoimmune Addison's disease

OBJECTIVE

To our knowledge, no case of remission in autoimmune Addison's disease has previously been reported. We describe a patient with primary adrenal insufficiency caused by autoimmune adrenalitis in whom partial remission was observed after 7 yr.

CASE

A 39-yr-old male was referred because of extreme fatigue, weight loss, anorexia, nausea, and bouts of fever. During physical examination hyperpigmentation was seen. Laboratory tests showed a plasma cortisol of 0.02 micromol/l (08:30 h). Cortisol failed to increase during the ACTH stimulation test (0.02 to 0.03 micromol/l) and ACTH was markedly elevated (920 pmol/l). Adrenal auto-antibodies were weakly positive. A CT-scan showed no evidence of calcifications or other abnormalities of the adrenal glands. The diagnosis of autoimmune Addison's disease was made and replacement therapy with hydrocortisone and fludrocortisone was started. During the following years the dose of hydrocortisone was gradually decreased. Eventually, the patient decided to stop his medication completely. A repeated ACTH-stimulation test revealed a basal cortisol of 0.25 micromol/l and a peak cortisol of 0.30 micromol/l with a basal ACTH of 178 pmol/l. The patient did not have any complaints.

CONCLUSION

Recovery of adrenal insufficiency, due to causes other than autoimmune adrenalitis, has been reported in the past. If our case of partial recovery of autoimmune adrenalitis is not unique this could have profound effects on treatment and follow-up of Addison's disease.

Long-term outcome of hormonal status in Taiwanese children with Hashimoto's thyroiditis

The objective of this prospective study was to evaluate both thyroid function in children with Hashimoto's thyroiditis and the necessity of lifetime thyroxine replacement therapy. A total of 47 patients with goiter and positive thyroid auto-antibodies participated in the study. Serum thyroxine and thyrotropin levels and titers of thyroid auto-antibodies were checked regularly throughout the follow-up period. At the beginning of the study, 25 patients were diagnosed as euthyroid, but at the end of the study, 22 patients initially diagnosed with euthyroidism remained euthyroid, while eight patients with subclinical hypothyroidism and three patients with overt hypothyroidism had become euthyroid. Thus, of the 22 patients with thyroid dysfunction at diagnosis, subclinical or overt, 11 became euthyroid during the follow-up period. The effect of thyroxine treatment on thyroid auto-antibody titers was not significant.

CONCLUSION

Our data shows that Hashimoto's thyroiditis in children has a benign course and that thyroid function in one half of the patients with thyroid dysfunction at diagnosis reverts to normal. Careful follow-up of thyroid function is important in order to determine the necessity and timing of thyroxine replacement therapy.

Thyroid autoantibodies in cord blood sera from children and adolescents with autoimmune thyroiditis

Autoimmune thyroid disease is common among women of childbearing age. Thyroid autoantibodies are predominantly of the immunoglobulin G (IgG)-type and pass the placental barrier from mother to child. Recent studies have suggested a pathogenetic role for transplacentally transmitted autoantibodies in the development of autoimmune disease. The aim of the present study was to investigate if children and adolescents with autoimmune thyroiditis (AIT) have been exposed to thyroid autoantibodies already in utero. Cord blood sera taken at delivery from 34 newborns who had developed AIT during childhood and adolescence, and sera from 31 of their mothers, were analyzed for the presence of autoantibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TgAb), and compared to 233 randomly selected control children and their mothers. The prevalence of TPOAb in cord blood sera was elevated among the children and adolescents with AIT compared to controls (38% versus 14%; odds ratio [OR] 4.12, p < 0.001). An increased prevalence of TPOAb was also found among their mothers (29% versus 15%; OR 2.17, p < 0.048). No significant difference in the prevalence of TgAb was found either between children with AIT and the control children (18% versus 9%; OR 2.16, p < 0.15), or between their mothers and the control mothers (23% versus 12%; OR 2.17, p < 0.16). Most of the TPOAb-positive children had TPOAb-positive mothers, indicating the maternal origin of their TPOAb. In conclusion, a large proportion of children who later developed AIT had already been exposed to transplacentally transmitted TPOAb in utero. Whether these autoantibodies have any pathogenetic role in the development of AIT in offspring or if they simply mirror the inheritance of AIT, remains to be investigated.

Autoimmune thyroid disease with fluctuating thyroid function

The authors describe the case of a woman with autoimmune thyroid disease, who presented with hypothyroidism but went on to develop hyperthyroidism.

Autoimmune thyroid disease in pregnant women and their offspring

OBJECTIVE

To present an overview of autoimmune thyroid disease (AITD) that can occur in pregnancy.

METHODS

The major thyroid antibodies that can traverse the maternal-fetal circulation and affect the fetus are summarized, those women at risk of having affected fetuses are identified, and the diagnosis, course, and treatment of AITD in maternal and neonatal patients are discussed.

SUMMARY

AITD, including Graves' disease and autoimmune thyroiditis, is common in women of childbearing age. Rarely, the fetus can be affected because of transplacental passage of maternal IgG. Of the thyroid autoantibodies found in AITD, only those directed against the thyroid-stimulating hormone (TSH) receptor have been shown to cause fetal thyroid dysfunction. Both transient neonatal hyperthyroidism and hypothyroidism have been described, as has delayed onset of neonatal hyperthyroidism due to the coexistence of stimulating and blocking TSH receptor antibodies. In general, affected infants are those born to mothers with the most potent antibody activity, and the duration of the neonatal thyroid dysfunction is dependent on the antibody titer and the rate of metabolic clearance from the infant's circulation. If fetal hyperthyroidism is suspected, maternal TSH receptor antibodies should be measured during the third trimester of pregnancy. For neonatal hypothyroidism, this measurement in the mother or baby soon after birth will suffice. Screening for the presence of TSH receptor antibodies by radioreceptor assay is the most cost-effective approach. If results are positive, bioassay should be done to determine the nature of the antibody activity. Women at risk of having babies with neonatal hyperthyroidism include those with a history of previous affected infants, with difficult to control thyrotoxicosis, or with a history of Graves' disease and development of hypothyroidism either spontaneously or as a result of thyroid gland ablation. Transient neonatal hypothyroidism due to TSH receptor-blocking antibodies should be suspected in any infant with hypothyroidism born to a mother with AITD (particularly those with previously affected offspring).

CONCLUSION

Treatment of maternal hyperthyroidism must consider both maternal and fetal thyroid status. In general, the lowest dose of antithyroid medication sufficient to produce maternal euthyroidism or slight hyperthyroidism is used. In pregnant women with hypothyroidism, doses of L-thyroxine should be sufficient to normalize maternal thyroid function without regard to the fetus. Identification and treatment of affected infants soon after birth will ensure a normal outcome. Whether inadequately treated maternal hypothyroidism is associated with a permanent intellectual deficit in the offspring is currently unknown.

Development of hyperthyroidism following primary hypothyroidism: a case report

Development of hyperthyroidism following primary hypothyroidism is uncommon, and only a few documented cases have been reported. Alterations in thyroid-stimulating hormone receptor antibodies in serum are currently considered to play the main role in the pathophysiology, but the exact mechanism is still unknown. Here, we report the case of a 60-year-old man with disturbed consciousness due to hyponatremia. Thyroid function tests showed primary hypothyroidism with a high anti-microsomal antibody titer (1:6,400). The patient experienced weight loss and exophthalmos 6 years later. Serum thyroid hormone levels were increased and thyroxine treatment was discontinued, but the patient remained thyrotoxic 2 months later. 131I thyroid uptake was 40.9% at 24 hours, and bilateral thyroid lobes were not enlarged with diffuse radioactivity. Six months later, the patient was still thyrotoxic and therapy with methimazole 10 mg/day was started. He is now taking methimazole and is euthyroid.

SENSITIVE THYROID-STIMULATING ANTIBODY ASSAY WITH HIGH CONCENTRATIONS OF POLYETHYLENE GLYCOL FOR THE DIAGNOSIS OF GRAVES' DISEASE

The aim of the present study was to determine the usefulness of a newly developed thyroid-stimulating antibody (TSAb) assay. We developed a highly sensitive TSAb (sTSAb) assay with 22.5% polyethylene glycol-precipitated crude IgG. The thyroid-stimulating hormone (TSH) receptor antibody (TRAb) causes Graves' disease and TRAb has been measured as TSH-binding inhibitor immunoglobulin (TBII) and thyroid-stimulating antibody (TSAb). The TSAb stimulates the thyroid glands and causes hyperthyroidism. In addition to investigating the usefulness of the newly developed sTSAb assay, we also investigated the frequencies of positive TRAb in thyrotoxic patients with subacute thyroiditis, painless thyroiditis or a solitary toxic nodule. We studied 700 untreated Graves' patients with hyperthyroidism and 923 normal controls. We also studied thyrotoxic patients with subacute thyroiditis, painless thyroiditis or a solitary toxic nodule. Conventional TSAb (cTSAb) and sTSAb were measured as TSAb, whereas porcine TBII (pTBII) and human recombinant TBII (hTBII) were measured as TBII. Levels of cTSAb and sTSAb were determined in 923 normal controls and 629 untreated Graves' patients and cTSAb and sTSAb were found to be normally distributed in normal controls, but not in untreated Graves' patients. Receiver operating characteristic (ROC) curve analysis demonstrated that cTSAb and sTSAb had high sensitivity and specificity for Graves' disease. Of the patients investigated, 96.5% of untreated Graves' patients were positive for sTSAb and/or pTBII. Some untreated Graves' patients who were negative for cTSAb were positive for sTSAb. Paired determinations of cTSAb and sTSAb were performed in 146 untreated Graves' patients. A positive correlation was found between cTSAb and sTSAb. Titres of sTSAb were higher than those of cTSAb and sTSAb had high sensitivity. Of the 35 untreated Graves' hyperthyroid patients who were negative for cTSAb, 18 (51%) were positive for sTSAb. Of the 36 untreated Graves' patients who were negative for hTBII, nine (25%) were positive for sTSAb. Some untreated Graves' patients who were negative for cTSAb were positive for sTSAb and some who were negative for hTBII and pTBII were positive for sTSAb. 5. Some thyrotoxic patients with subacute thyroiditis or painless thyroiditis were positive for TRAb. However, the frequency of TRAb-positive patients was low in this group. None of the patients with a solitary toxic nodule was positive for TRAb. In conclusion, sTSAb had higher sensitivity than cTSAb. Graves' patients who were cTSAb negative and hTBII negative could be sTSAb positive. The sTSAb indicates TSAb activity, but pTBII and hTBII do not necessarily do so. We recommended that the sTSAb is used in Graves' patients.

Autoimmune thyroid diseases: etiology, pathogenesis, and dermatologic manifestations

Autoimmune thyroid disease (AITD) including Graves' disease, Hashimoto's thyroiditis, and idiopathic hypothyroidism (atrophic Hashimoto's thyroiditis) is of vital concern to the dermatologist. This article reviews the cutaneous manifestations of Graves' disease and Hashimoto's thyroiditis. Recognition of dermatologic manifestations of AITD may alert practitioners to investigate for these disorders. The immune response involved in the pathogenesis of AITD is detailed. Current understanding of the role of genetic and environmental factors, antigens, and apoptosis are elaborated. The future holds exciting insight into the etiology, pathogenesis, and treatment of AITD.

TSH-receptor antibody measurement in patients with various thyrotoxicosis and Hashimoto's thyroiditis: a comparison of two two-step assays, coated plate ELISA using porcine TSH-receptor and coated tube radioassay using human recombinant TSH-receptor

The aim of this study was to compare two two-step assays, a new coated plate (CP) ELISA assay (TRAb ELISA) using purified porcine TSH-receptors (pTSH-R) and a coated tube assay (CT) using recombinant human TSH-receptors (hTSH-R) (DYNO(R) test TRAK human). The same serum samples were used for the determination by both assays in patients with 100 untreated Graves' disease (GD), 30 silent thyroiditis (ST), 10 subacute thyroiditis (SAT) and 87 Hashimoto's thyroiditis (HT). In sera from patients with untreated GD, pTBII and hTBII were positive in nearly all cases except the same one, whereas the thirty sera from the ST had positive values of pTBII in one case and of hTBII in 4 cases. In the one ST case of both pTBII and hTBII positive, hyperthyroidism developed following ST, although the remaining ST cases including the three hTBII-positive cases were not followed by hyperthyroidism after ST attack. A positive value of hTBII was observed in one of 10 patients with SAT, whereas none of them was pTBII positive. In the 87 patients with HT, positive values of pTBII were recognized in 9 patients, whereas hTBII is positive in 10 patients. Serum TSAb and TSBAb activities were analyzed in the hTBII positive 7 patients. As a result, TSAb was all positive except one and TSBAb positive in 4 cases. Since there is no significant difference in the sensitivity and specificity between the two assays in the differentiation of thyrotoxicosis as well as the frequency of finding positive values in patients with HT, it is reasonable to conclude that the clear advantage of sensitivity for clinical application in the new CP and CT assays may be derived from the coated plate or coated tube assay itself, which probably excludes the effect of anti-TSH antibodies and HAMA, and is unrelated to the use of human or porcine TSH-receptors.

Epidemiology and prevention of clinical and subclinical hypothyroidism

Iodine deficiency is the most common cause of hypothyroidism worldwide. In persons living in iodine-replete areas, causes are congenital, spontaneous because of chronic autoimmune disease (atrophic autoimmune thyroiditis or goitrous autoimmune thyroiditis [Hashimoto's thyroiditis]), or iatrogenic because of goitrogens, drugs, or destructive treatment for thyrotoxicosis. Screening for congenital hypothyroidism exists and its use prevents mental retardation. The prevalence of spontaneous hypothyroidism is between 1% and 2% and is more common in older women and 10 times more common in women than in men. A significant proportion of subjects have asymptomatic chronic autoimmune thyroiditis and 8% of women (10% of women over 55 years of age) and 3% of men have subclinical hypothyroidism. Approximately one third of patients with newly diagnosed overt hypothyroidism have received destructive therapy for hyperthyroidism and indefinite surveillance is required. There is not much that can be done to prevent the occurrence of spontaneous autoimmune hypothyroidism, but if identified early, something can be done to prevent progression to overt disease. Controversy exists as to whether healthy adults would benefit from screening for autoimmune thyroid disease because a significant proportion of subjects tested will have evidence of mild thyroid failure. Case finding in women at menopause or visiting a primary care physician with nonspecific symptoms appears justified.

Immunology primer

The immune system, through a complex interplay of highly specialized cells and a seemingly endless number of soluble mediators, works to ensure protection from the potentially harmful pathogens that we encounter in our lifetime. The development of the immune system is a compromise between the necessity to recognize foreign peptides in the context of self-molecules (MHC) and the need to be tolerant to all self-peptides. Despite the large number of mechanisms in place to ensure the removal or suppression of self-reactive lymphocytes, the system is not 100% effective, with the occasional result of autoimmunity. A number of autoimmune disorders occur together and a better understanding of the genetic basis underlying this association should lead to an enhanced ability to predict, diagnose, and develop therapies aimed at preventing and treating these diseases.

TSH-receptor antibody measurement for differentiation of hyperthyroidism into Graves' disease and multinodular toxic goitre: a comparison of two competitive binding assays

OBJECTIVES

Graves' disease is characterized by stimulating autoantibodies to the TSH-receptor (TRAb). The aim of this study was to compare the performance of a new TRAb assay based on competitive binding to recombinant human TSH-receptors (H-TRAb) with an assay employing purified porcine TSH-receptors (P-TRAb). Furthermore, to evaluate the applicability of the H-TRAb assay to discriminate between patients with hyperthyroidism due to Graves' disease (GD) and multinodular toxic goitre (MNTG).

DESIGN AND MEASUREMENTS

H-TRAb and P-TRAb were measured in patients with newly diagnosed hyperthyroidism due to GD (n = 106) and MNTG (n = 94). For comparison, TRAb was measured in patients with primary autoimmune hypothyroidism, euthyroid subjects with an enlarged thyroid gland by ultrasound, and healthy controls (n = 100 for each group). Patients were consecutively included from a population survey.

RESULTS

If the cut-off values recommended by the manufacturer for TSH-receptor antibody positivity were used for evaluation, the sensitivity of the H-TRAb assay vs. the P-TRAb assay in diagnosing GD was: 95.3/67.9% (P < 0.001). Specificity was (H/P-TRAb): 99/99%. The sensitivity of P-TRAb was increased if the upper 97.5% limit of measurements in controls was used as cut-off (H-TRAb vs. P-TRAb: 95.3/80.2%, P < 0.001). Specificity (H/P-TRAb): 98/98%. The difference between assay performance may partly be due to a better technical performance of the H-TRAb assay with more reliable results in the low range of measurements. However, even in GD patients with clearly measurable TRAb, 25% had a P-TRAb < 50% of the value expected from the H-TRAb measurement. This suggests that a subgroup of patients produce TRAb with a higher affinity for the human than the porcine TSH receptor. A relatively high proportion of patients with MNTG were TRAb positive (H-TRAb/P-TRAb: 17/9%). Characteristics of H-TRAb positive and negative MNTG patients were compared. There was no difference between size of thyroid gland and number of nodules by ultrasonography. H-TRAb positive patients had significantly higher serum T4 and T3 and a greater number were TPO-Ab positive.

CONCLUSIONS

H-TRAb diagnosed Graves' disease with a high sensitivity and specificity than P-TRAb. The high occurrence of TRAb in multinodular toxic goitre might in part reflect an overlap between Graves' disease and multinodular toxic goitre in some patients.

Thyroid autoantibodies

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

Anti-TSH receptor antibodies in clinical practice

Anti-thyroid stimulating hormone receptor antibodies are pathophysiologic and clinical indicators in autoimmune thyroid diseases, not only in Graves' disease. The detection of these antibodies is useful for diagnostic and management purposes. The presence and titers of anti-TSH receptor antibodies, however, have to be interpreted in light of the clinical and other biological characteristics of each patient. Newer, more sensitive assays of anti-TSH receptor antibodies may increase their significance in the diagnosis and management of autoimmune thyroid diseases and Graves' disease.

When to treat mild hypothyroidism

The availability and wide acceptance of TSH assays for primary assessment of thyroid function has led to the recognition that mild thyroid hormone deficiency is characterized by elevation of the serum TSH concentration despite a normal free thyroxine level. Other conditions can also cause isolated serum TSH elevation, and these conditions can be distinguished from mild thyroid failure usually based-on clinical and circumstantial observations alone. Thyroxine treatment of patients with mild hypothyroidism has been shown in most, but not all, clinical trials to lower atherogenic lipid levels and relieve certain somatic and neuropsychiatric symptoms. Such treatment also prevents the progression to overt hypothyroidism, which is particularly likely in patients who are older, who have circulating thyroid autoantibodies, or who have a serum TSH greater than 10 mU/L. After the optimal thyroxine dose has been defined, long-term monitoring of patients with an annual clinical evaluation and serum TSH measurement is appropriate. The high prevalence of mild hypothyroidism, particularly in older women, and its subtle clinical presentation have led some authorities to recommend a low threshold for case-finding or routine population screening for the disorder.