Metamorphic thyroid autoimmunity

Actual Associations between HLA Haplotype and Graves' Disease Development

The association between HLA and the risk of Graves’ disease (GD) has been analyzed for many years. However, the results were often inconsistent and mostly regarded Asian populations. The purpose of our study was to perform HLA genotyping using a next-generation sequencing (NGS) method in Caucasians, to find out which alleles are eventually correlated with GD morbidity as well as which of them can be considered protective. HLA-A, -B, -C, -DQB1, -DRB1 were genotyped using a next-generation sequencing method in 2376 persons, including 159 GD patients and 2217 healthy controls. We have demonstrated a significant association between the risk of GD and the following alleles: HLA-B*08:01, -B*39:06, -B*37:01, -C*07:01, -C*14:02, -C*03:02, -C*17:01, -DRB1*03:01, -DRB1*11:01, -DRB1*13:03, -DRB1*01:03, -DRB1*14:01, -DQB1*03:01, DQB1*02:01. The alleles HLA-B*39:06, -B*37:01, -C*14:02, -C*03:02, -C*17:01, -DRB1*14:01 are novel GD-associated, previously not-reported independent ones with no linkage disequilibrium with other high-risk alleles. On the other hand, the frequencies of HLA-B*07:02, -C*07:02, -C*03:04, DRB1*07:01, -DQB1*02:02, -DQB1*03:03 were significantly lower in GD compared to controls. This study demonstrated the actual relationships between HLA and GD based on the NGS method and provided a novel set of alleles as a reliable tool for an individual personalized risk assessment.

Radioactive Iodine for the Treatment of Subclinical Thyrotoxicosis Grade 1 and 2: Outcome of up to 18-Year Follow Up

BACKGROUND

Subclinical thyrotoxicosis (SCT) is associated with significant morbidity and mortality, specifically increased risk of atrial fibrillation and cardiovascular death. The management is ill-defined due to the scarcity of randomised controlled studies. Some clinicians recommend radioiodine (RAI) treatment however its long-term outcome is unknown. Therefore, further data is needed to provide robust evidence-based guidelines.

METHODS

A prospective, single-protocol analysis of the outcome of SCT patients (Grade 1; 0.1-0.4 mIU/L and Grade 2; <0.1 mIU/L) treated with mean dose of 427 MBq of I¹³¹, followed up for up to 18 years. Thyroid function tests were measured at 4-6 weeks, 3-, 6-, and 12-months post-RAI, and annually thereafter. Cure was defined as achieving a euthyroid/hypothyroid state.

RESULTS

Seventy-eight patients with a median age of 68 years (range 36-84) and varying aetiology [55 toxic multinodular goitre (TMNG), 10 toxic nodule (TN) and 13 Graves' disease (GD)] were followed up for a median period of 7.5 years (range 1-18). The cure rate was 100%. The rates of hypothyroidism in TMNG, TN and GD were 23.6%, 30% and 38.5% respectively. The median time to hypothyroidism was 6 and 12 months in GD and TMNG/TN respectively. No differences in outcome between Grade 1 versus Grade 2 were observed.

CONCLUSION

RAI using single mean dose of 427 MBq is effective and safe, irrespective of aetiology or grade of TSH suppression. GD patients become hypothyroid within the first year, whilst TMNG/TN for up to 9-years. Thus after 12 months of follow up, annual thyroid function monitoring is advised.

Graves disease in infancy: a patient presentation and literature review

SUMMARY

We describe a case of an infant who presented with clinical features of hyperthyroidism. The child was found to be tachycardic, hypertensive and diaphoretic, she was noted to have poor weight gain and difficulty in sleeping. The child was admitted to the pediatric intensive care unit for care. She was found to have biochemical evidence of hyperthyroidism with positive thyroid stimulating immunoglobulin. She responded well to methimazole and propranolol and had a remarkable recovery. She is the youngest patient to be diagnosed with Graves disease in the English literature, at 12 months of life.

LEARNING POINTS

Hyperthyroidism must always be considered even at very young age, for patient presenting with poor weight gain and hyperdynamic state. Autoimmune diseases are becoming more common in infancy. Craniosynostosis and increased height for age are well-documented consequences of untreated hyperthyroidism in developing children.

The clinical phenotype of Graves' disease occurring as an isolated condition or in association with other autoimmune diseases

PURPOSE

Graves' disease (GD) can present as an isolated disease (iGD) or in association with other autoimmune diseases (aGD). The aim of this study, performed in two Endocrine referral centers settled in different geographical areas of Italy, was to compare the anthropometric, clinical, and biochemical phenotype of iGD patients with that of the aGD ones.

METHODS

Clinical history, physical examination data, serum levels of TSH, FT4, FT3, thyroglobulin (TgAb), thyroid-peroxidase (TPOAb) and TSH-receptor (TRAb) antibody, presence of Graves' orbitopathy (GO), and thyroid ultrasound examination at disease diagnosis were recorded.

RESULTS

68 aGD and 136 iGD patients were consecutively recruited. At diagnosis, aGD and iGD patients did not differ for F/M ratio, age at presentation, thyroid function parameters, serum levels of TRAb, TgAb, TPOAb, presence of GO, and thyroid volume. The serum levels of TRAb were strongly correlated with the circulating concentrations of both FT3 (ρ = 0.667; p < 0.0001) and FT4 (ρ = 0.628; p < 0.001) in iGD patient, but not in the aGD ones (FT3: ρ = 0.231; p = 0.058; FT4: ρ = 0.096; p = 0.435). Compared with iGD patients, the aGD ones displayed a higher rate of transition from the previous hypothyroidism to hyperthyroidism (χ² = 6.375; p = 0.012).

CONCLUSION

Despite similar anthropometric, clinical, and biochemical features at diagnosis, aGD patients display a higher rate of transition from a thyroid functional status to the other as compared with iGD patients.

Phenotypic Expression of Autoimmunity in Children With Autoimmune Thyroid Disorders

Autoimmune thyroid diseases (AITDs), including Hashimoto's thyroiditis (HT) and Graves' disease (GD), tend to aggregate with other non-thyroidal autoimmune diseases (NTADs). Aim of this Mini-review is to report the most recent insights concerning the clustering of NTADs in pediatric patients with either HT or GD, the pathophysiology of AITDs and the metamorphic thyroid autoimmunity. A systematic literature research of the last 15 years, according to EQUATOR statement, was carried out through MEDLINE via PubMed (http://www.ncbi.nlm.nih.gov/pubmed/) Embase, CINAHL, Cochrane Library, based on the following keywords: (autoimmune thyroid disease OR Hashimoto thyroiditis OR Grave's disease) AND (autoimmune comorbidities OR extra-thyroidal autoimmune disorders) AND (children OR adolescents OR pediatrics) AND (celiac disease OR type 1 diabetes mellitus OR arthropathies OR cutaneous diseases) AND (Turner syndrome OR Down syndrome). One-hundred and twenty-eight manuscripts were extrapolated but only seventeen were eligible. On the basis of the available reports it may be inferred that clustering of NTADs can be significantly modified by both patients' age at AITDs presentation and association with Down's syndrome (DS). Particularly, the association of AITDs with celiac disease and type 1 diabetes was most commonly reported in children than in adults. A sequential shifting from HT to GD has been described in children with AITDs, and it seems to be more frequent in children with DS than in those without DS. Coexistence of autoimmune diseases might be the result of a complex interaction among genetics, environment and epigenetic modifications that are able to affect gene expression, immune system response and, finally, the pathogenesis of autoimmune diseases.

Association between Hashimoto's thyroiditis and cholelithiasis: a retrospective cohort study in Taiwan

OBJECTIVE

To investigate the relation of Hashimoto's thyroiditis (HT) to cholelithiasis and cholecystectomy in a retrospective population-based study.

SETTING

Cohort study.

PARTICIPANTS

We identified 1268 patients aged ≥20 years with HT between 2000 and 2010 as the study cohort.

PRIMARY AND SECONDARY OUTCOME MEASURES

Patients without HT were randomly selected from a database and propensity-matched with the study cohort at a 1:4 ratio according to age, sex, comorbidities and year of the index date to measure the incidence of cholelithiasis and cholecystectomy.

RESULTS

The cumulative incidence of cholelithiasis was higher in the HT cohort than that in the non-HT cohort (log-rank test, p<0.001), with a 1.91-fold higher risk of choleithiasis (95% CI 1.58 to 2.33) after adjustment for comorbidities. The age-specific relative risk of cholelithiasis in the HT cohort was higher than that in the non-HT cohort for patients aged ≥50 years (adjusted HR (aHR)=2.59, 95% CI 1.33 to 5.03). The sex-specific relative risk of cholelithiasis in the HT cohort was higher than that in the non-HT cohort for women (aHR=1.99, 95% CI 1.63 to 2.44). Compared with those in the non-HT cohort, patients with HT without (aHR=1.95, 95% CI 1.53 to 2.49) and with (aHR=1.94, 95% CI 1.51 to 2.49) thyroxine treatment were associated with a higher risk of cholelithiasis. Compared with those in the non-HT cohort, patients with HT had a higher risk of cholecystectomy (aHR=1.28, 95% CI 1.02 to 1.61).

CONCLUSIONS

Inability to obtain information on several potential confounding factors and misclassification of important covariates are the major limitations of the study. Our study indicates HT per se was associated with the development of cholelithiasis, which has been validated by the association between cholecystectomy and HT. Surveys and health education on cholelithiasis in women aged ≥50 years with HT should be considered by clinicians, and further prospective research should be done on this topic.

Thyroid Disorders in Subjects with Down Syndrome: An Update

Down syndrome (DS) is the commonest chromosomal disorder among live born infants. DS is associated with increased risk of endocrine abnormalities particularly thyroid gland disorders. The spectrum of thyroid dysfunction in patients with DS include congenital hypothyroidism, subclinical hypothyroidism, acquired hypothyroidism (autoimmune - non autoimmune), and hyperthyroidism. This review will focus on the characteristics of the different presentations of thyroid abnormalities in DS, screening and management recommendations. (www.actabiomedica.it)

Epidemiological and clinical aspects of autoimmune thyroid diseases in children with Down's syndrome

Aim of this commentary is to report the main peculiarities that have been found to characterize the phenotypic expression of autoimmune thyroid diseases (AITDs) in children with Down's syndrome (DS). According to recent reports, DS children are, per se, more exposed to the risk of both Hashimoto's thyroiditis (HT) and Graves' disease (GD), irrespective of other concomitant risk factors, such as female gender and family antecedents for AITDs. In the context of extra-thyroidal autoimmune disorders, the ones that preferentially aggregate with AITDs in DS children are alopecia areata and vitiligo. Another peculiar aspect, in DS children, is that HT presents with a more severe biochemical picture, which furtherly deteriorates over time. By contrast, GD does not demonstrate a more severe clinical and biochemical picture with respect to that generally observed in patients without DS. Finally, DS children might be at higher risk of progressing from HT toward GD over time.

Thyroid function test evolution in children with Hashimoto's thyroiditis is closely conditioned by the biochemical picture at diagnosis

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Aim of this commentary is to summarize the salient literature views on the relationships between presentation and evolution patterns of thyroid function in children with Hashimoto’s thyroiditis (HT).

According to the most recent reports, children with HT and subclinical hypothyroidism (SH) are more prone to the risk of developing severe thyroid dysfunctions over time, if compared to those presenting with euthyroidism.

In contrast, children presenting with HT and either overt or subclinical hyperthyroidism are incline to exhibit a definitive resolution of the hyperthyroid phase within some months, although there is a wide variability between the different individuals.

The natural history of frank hypothyroidism in the children with HT has never been investigated so far, since in these cases an immediate onset of replacement treatment is mandatory.

Conclusions

1) a deterioration of thyroid status over time may be observed especially in the children presenting with SH, but also in those presenting with euthyroidism; 2) a definitive resolution of the hyperthyroid phase is generally observed in those presenting with either overt or subclinical hyperthyroidism.

Five-Year Prospective Evaluation of Thyroid Function Test Evolution in Children with Hashimoto's Thyroiditis Presenting with Either Euthyroidism or Subclinical Hypothyroidism

BACKGROUND

Whether the course of thyroid function in Hashimoto's thyroiditis (HT) differs in children who present with either euthyroidism or subclinical hypothyroidism (SH) has been incompletely investigated.

AIM

Using a five-year prospective evaluation of 234 children with HT and no prognostic risk factors, this study investigated whether the evolution of the thyroid status is influenced by the biochemical pattern at initial diagnosis.

RESULTS

In the entire series, thyrotropin values significantly increased during follow-up, while free thyroxine values decreased and the proportion of children with a thyroid dysfunction increased from 27.3% to 47.4% (p = 0.0001). An increasing proportion of cases with severe thyroid dysfunction was identified, especially among the 64 patients presenting with SH (group B), but also among the 170 children presenting with euthyroidism (group A) at initial diagnosis. At the end of follow-up, the prevalence of children with overt hypothyroidism was 12.3% in group A compared with 31.2% in group B (p = 0.0007). In the overall population, however, the majority of patients (52.6%) exhibited biochemical euthyroidism at the end of follow-up.

CONCLUSIONS

Children with HT may develop a deterioration of thyroid status during the first five years of disease. Such a trend may be observed, even in the patients who initially present with a mild biochemical picture (either SH or euthyroidism). A total of 57.1% of initially euthyroid children remain euthyroid, and 40.6% of patients with initial SH normalize thyroid function within five years after HT diagnosis. The patients presenting with SH are more prone to the risk of developing severe thyroid dysfunction over time.

Five-year prospective evaluation of thyroid function in girls with subclinical mild hypothyroidism of different etiology

AIM

To follow-up for 5 years thyroid status evolution in 127 girls with mild (TSH 5-10 mU/l) subclinical hypothyroidism (SH) of different etiologies.

PATIENTS

The population was divided into two age-matched groups of 42 and 85 girls with either idiopathic (group A) or Hashimoto's thyroiditis (HT)-related SH (group B). Group B was in turn divided into three subgroups, according to whether SH was either isolated or associated with Turner syndrome (TS) or Down syndrome (DS).

RESULTS

At the end of follow-up the rate of girls who became euthyroid was higher in group A (61.9% vs 10.6%), whereas the rates of patients who remained SH (55.3% vs 26.2%), became overtly hypothyroid (30.6% vs 11.9%) or required levothyroxine (l-T4) therapy (63.5% vs 23.8%) were higher in group B. Among the girls of group B, the risk of remaining SH or developing overt hypothyroidism was higher in the subgroups with TS or DS than in those with isolated HT.

CONCLUSIONS

Long-term prognosis of mild and idiopathic SH is frequently benign, even though a l-T4 treatment may be needed throughout follow-up in almost a quarter of cases; long-term prognosis is different in the girls with either idiopathic or HT-related SH; and the association with either TS or DS impairs the outcome of HT-related SH.

The association with Turner syndrome significantly affects the course of Hashimoto's thyroiditis in children, irrespective of karyotype

Only few studies have investigated to now whether the association with Turner syndrome (TS) may affect the course of Hashimoto's thyroiditis (HT) in children. Aim of this study was to ascertain whether the presentation and long-term course of HT in TS children may be characterized by a peculiar and atypical pattern. The clinical and biochemical findings at HT diagnosis in 90 TS children (group A) were compared with those recorded in 449 girls with HT but without TS (group B); in group A patients, thyroid function tests were re-evaluated after a median time interval of 4.9 years. At HT diagnosis median TSH levels and the rate of cases presenting with a thyroid dysfunction picture were significantly lower in group A, irrespective of karyotype abnormalities. In group A only 34.8 % of the girls who had initially presented with euthyroidism remained euthyroid even at re-evaluation, whilst 67.7 % of those who had presented with subclinical hypothyroidism became overtly hypothyroid over time; also such evolutive pattern was irrespective of karyotype abnormalities. (1) In TS girls, HT presents with a milder hormonal pattern, which often deteriorates over time; (2) these biochemical features are not necessarily linked with a specific karyotype.

Metamorphic thyroid autoimmunity in Down Syndrome: from Hashimoto's thyroiditis to Graves' disease and beyond

BACKGROUND

It is known that Hashimoto's thyroiditis (HT) may progress to Graves' disease (GD) and that this phenomenon may be more frequent in the patients with Down syndrome (DS).

AIMS

To shed light on the relationships between Down syndrome (DS) and metamorphic thyroid autoimmunity.

PATIENTS AND METHODS

We reconstructed the conversion process from HT to GD in 12 DS children. All the data recorded at HT diagnosis and throughout the time interval from entry to GD presentation were retrospectively taken from patients' files, as well as those recorded at GD diagnosis and during the subsequent evolution. From GD diagnosis all patients underwent methimazole treatment, at a dose that was adjusted on the basis of clinical findings and thyroid tests.

RESULTS

Time interval between HT and GD was not different in the seven patients who received during that time a L-thyroxine (L-T4) treatment than in those who were not treated. After methimazole onset all patients exhibited a prolonged remission of hyperthyroidism. In 8/12 patients this treatment is still being continued 2-7 years after its initiation. The mean methimazole dosage needed to maintain euthyroidism in these eight patients was 0.12 ± 0.02 mg/kg/day. In the remaining four patients methimazole was withdrawn from 1.9 to 7 years after its initiation and no relapses were recorded 2.0-2.1 years after its withdrawal. These patients developed, 0.1-0.3 years after methimazole withdrawal, a picture of overt hypothyroidism and needed treatment with L-T4, that is now being continued. No patients needed non-pharmacological therapies.

CONCLUSIONS

1) DS children might be incline to manifest over time a phenotypic metamorphosis from HT to GD and to subsequently fluctuate from hyperthyroidism to hypothyroidism; 2) in DS GD may have a mild biochemical and clinical course.

Peculiarities of autoimmune thyroid diseases in children with Turner or Down syndrome: an overview

Aim of this commentary is to summarize the salient literature news on the relationships between autoimmune thyroid diseases (ATDs) and either Down syndrome (DS) or Turner syndrome (TS).According to literature reports both Hashimoto's thyroiditis (HT) and Graves' disease (GD) are more frequent in children with DS or TS than in those without these chromosomopathies.An up-regulation of proinflammatory cytokines might be responsible for the enhanced susceptibility of TS children to ATDs, whereas a dysregulation of immune system may favor the development of ATDs in DS.In TS children biochemical presentation of HT is less severe than in peer controls. In both DS and TS GD picture at the time of diagnosis is not significantly different than in the pediatric general population.The evolution over time of GD in DS and TS does not differ from that observed in the pediatric general population, whereas the evolution of HT in both TS and DS is more severe than in girls without these chromosomopathies.

CONCLUSIONS

The association with TS or DS is able to affect both epidemiology and course of ATDs by conditioning: a) an increased susceptibility to these disorders; b) a less severe biochemical presentation and a more severe evolutive pattern of HT in TS girls; c) a more severe biochemical presentation and evolution of HT in DS patients.

In young patients with Turner or Down syndrome, Graves' disease presentation is often preceded by Hashimoto's thyroiditis

BACKGROUND

It is known that, in the general population, there exists a continuum between Hashimoto's thyroiditis (HT) and Graves' disease (GD) within the spectrum of autoimmune thyroid diseases, although the mechanisms involved in the metamorphosis from HT to GD or vice versa have not been elucidated as of yet. The aim of this study was to ascertain whether the association with Down or Turner syndromes (DS and TS) may affect the switching process from HT to GD.

METHODS

Thirty-five young GD patients with either DS or TS (group A) and 109 age-matched GD patients with neither DS nor TS were retrospectively investigated in order to either confirm or exclude antecedents of HT. The investigations were based on either clinical records or questionnaires addressed to family pediatricians. Retrospective investigations also aimed to ascertain how many patients in each group exhibited a biochemical picture of either subclinical or overt hypothyroidism at the time of HT diagnosis, and how many had received levothyroxine (L-T4) therapy prior to the onset of GD. In both groups, all the patients with documented antecedents of HT underwent an assessment of their iodine status after GD diagnosis.

RESULTS

Antecedents of HT were significantly more common in group A than in group B (25.7% vs. 3.7%, p=0.0004), with a time interval between HT and GD that was significantly higher in group A (p=0.003). Both thyroid function and autoimmunity tests at HT presentation and the prevalence of patients who underwent L-T4 therapy prior to GD diagnosis were not significantly different in the two groups, nor was the iodine status after GD diagnosis.

CONCLUSIONS

In young patients with TS or DS, GD presentation is often (25.7% of cases) preceded by HT. This evolution trend does not seem to be conditioned by either thyroid tests at HT diagnosis, or L-T4 treatment, or iodine status alterations. Patients with these chromosomopathies and coexisting HT may be at high risk of progressing to GD. The pathophysiological bases of these findings need to be clarified.

Subclinical hyperthyroidism when presenting as initial manifestation of juvenile Hashimoto's thyroiditis: first report on its natural history

BACKGROUND

Due to the lack of specific pediatric studies, no data are available about natural history of endogenous subclinical hyperthyroidism (SH) in childhood.

AIMS

(a) To investigate for the first time the natural history of SH [suppressed thyrotropin (TSH) and normal free thyroxine free thyroxine (FT4) levels] when presenting as initial manifestation of Hashimoto's thyroiditis (HT) in childhood (group A); (b) to compare spontaneous evolution of HT-related SH with that observed in age-matched patients with HT-related frank hyperthyroidism (suppressed TSH and elevated FT4 levels), i.e., Hashitoxicosis Htx (group B).

RESULTS

In the 11 patients of group A, TSH normalization spontaneously occurred 1-24 months after diagnosis, while in the 10 patients of group B it occurred 3-9 months after diagnosis, with no differences between the 2 groups in terms of time interval from entry to TSH normalization. In group A, this time interval was related to baseline thyroid peroxidase antibodies (r=0.78, p = 0.04). During follow-up, eight patients of each group remained euthyroid, whereas two became hypothyroid (in both groups) and one developed Graves' disease (in group A).

CONCLUSION

(a) HT should be included among the causes of endogenous SH in pediatric age; (b) in children with HT-related SH, spontaneous normalization of TSH levels occurs within the first 24 months after diagnosis, as well as in age-matched patients with Htx; (c) in both these conditions, a further deterioration of thyroid function might re-present in some patients during follow-up; (d) Ht-related SH and Htx might be possibly seen as different biochemical stages along the same continuum.

Hashimoto's thyroiditis in childhood: presentation modes and evolution over time

Aim of this survey is to report the most recent views about Hashimoto’s thyroiditis (HT) natural history according to the different presentations. In children presenting with either euthyroidism or subclinical hypothyroidism HT spontaneous course is frequently characterized by a trend towards deterioration of thyroid function, whereas in those presenting with overt hyperthyroidism a definitive resolution of hyperthyroid phase is to be expected. Another possible even though unusual outcome of HT is the conversion to Graves’ disease.

[Spontaneous hypothyroidism in 4 patients with Graves-Basedow disease]

We present 4 patients with Graves' disease who developed spontaneous hypothyroidism during follow-up. The two most plausible physiopathologic mechanisms for this development were progressive autoimmune-mediated destruction of the thyroid follicular epithelium and a predominance of blocking antibodies to the thyroid-stimulating hormone (TSH) receptor at the expense of stimulating antibodies in the same patient. Description of these patients not only illustrates the heterogeneous nature of this disease, but also the interrelation among its distinct clinical forms.