Seasonal variation in relapse rate of graves' disease after thionamide drug treatment

HLA Class I Upregulation and Antiviral Immune Responses in Graves Disease

CONTEXT

The origin of Graves disease (GD) remains elusive. However, evidence of an association between GD and viral infections is emerging. Human leukocyte antigen (HLA) class I presents viral antigens to circulating immune cells and plays a crucial role in the defense against viral infections.

OBJECTIVE

This work aimed to investigate HLA class I expression, enterovirus presence, and the viral immune response proteins signal transducer and activation of transcription 1 (STAT1) and protein kinase R (PKR) in thyroid tissue from GD patients.

METHODS

We collected thyroid tissue from core needle biopsies or surgical specimens from 48 GD patients and 24 controls. Standard immunohistochemistry was used to detect HLA class I and enteroviral capsid protein 1 (VP1) on formalin-fixed and paraffin-embedded tissue. STAT1 and PKR were examined by combined immunofluorescence staining. HLA class I expression score was the main outcome measure.

RESULTS

The HLA class I expression score, which takes both proportion and intensity of immunostaining into account, was significantly higher in GD patients (3.1 ± 3.3) than in controls (0.5 ± 0.9) (P < .001). Significantly more VP1 positive thyroid cells were found GD samples (50.1 ± 30.5%) than in controls (14.9 ± 10.5%) (P < .001). STAT1 and HLA class I were found within the same thyroid cells and PKR and VP1 were also colocalized within thyroid cells.

CONCLUSION

HLA class I is upregulated in GD and enterovirus protein is prevalent in thyroid tissue. The colocalization of HLA class I with STAT1 and VP1 with PKR indicates an antiviral tissue response. These findings support the concept of a link between viral infections and GD.

Graves' disease in children in the two decades following implementation of an iodine prophylaxis programme

Grave’s disease (GD) is a form of thyroid autoimmune disease characterised by hyperthyroidism. It is a rare clinical problem in paediatrics. Development of disease is the result of genetic susceptibility and some environmental factors. One of the best-documented environmental factors involved in thyroid autoimmunity is iodine excess. The aim of our study was to analyse the clinical course and response to pharmacological treatment in children diagnosed with Graves’ disease in first two decades after mandatory salt iodination. Records of 94 children diagnosed with GD in the years 1998-2017 were analysed. Medical data of patients was compared between two decades following implementation of iodine prophylaxis: 1998-2007 (first-decade group – FDG) and 2008-2017 (second-decade group – SDG); 34 and 60 patients, respectively. Medical data of FDG was obtained from archival records and previous analysis performed in 2006. Data of 60 patients from SDG were obtained from currently available medical records. Results were statistically analysed using Microsoft Excel and Statistica 11 software. Results: In our study, after mandatory salt iodination, the tendency of an increase in newly diagnosed GD in children without family susceptibility was observed. The antibody profile indicates the significant contribution of the autoimmune process involving all thyroid antigens; therefore, the term “autoimmune hyperthyroidism” seems to be more appropriate than classical GD in this group of patients. The first-choice treatment with methimazole rarely causes adverse events during the therapy, and they have benign character.

The microbiota and autoimmunity: Their role in thyroid autoimmune diseases

Since the 1970s, the role of infectious diseases in the pathogenesis of Graves' disease (GD) has been an object of intensive research. The last decade has witnessed many studies on Yersinia enterocolitica, Helicobacter pylori and other bacterial organisms and their potential impact on GD. Retrospective, prospective and molecular binding studies have been performed with contrary outcomes. Until now it is not clear whether bacterial infections can trigger autoimmune thyroid disease. Common risk factors for GD (gender, smoking, stress, and pregnancy) reveal profound changes in the bacterial communities of the gut compared to that of healthy controls but a pathogenetic link between GD and dysbiosis has not yet been fully elucidated. Conventional bacterial culture, in vitro models, next generation and high-throughput DNA sequencing are applicable methods to assess the impact of bacteria in disease onset and development. Further studies on the involvement of bacteria in GD are needed and may contribute to the understanding of pathogenetic processes. This review will examine available evidence on the subject.

A possible link between the Epstein-Barr virus infection and autoimmune thyroid disorders

The Epstein-Barr virus (EBV), also known as human herpesvirus 4, is a member of the Herpesviridae virus family. EBV infection can cause infectious mononucleosis (IM) in the lytic phase of EBV's life cycle. Past EBV infection is associated with lymphomas, and may also result in certain allergic and autoimmune diseases. Although potential mechanisms of autoimmune diseases have not been clearly elucidated, both genetic and environmental factors, such as infectious agents, are considered to be responsible for their development. In addition, EBV modifies the host immune response. The worldwide prevalence of autoimmune diseases shows how common this pathogen is. Normally, the virus stays in the body and remains dormant throughout life. However, this is not always the case, and a serious EBV-related illness may develop later in life. This explains the chronic course of autoimmune diseases that is often accompanied by exacerbations of symptoms. Based on the present studies, EBV infection can cause autoimmune diseases, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), rheumatoid arthritis (RA), Sjögren's syndrome, and autoimmune hepatitis. The EBV has also been reported in patients with autoimmune thyroid disorders. Although EBV is not the only agent responsible for the development of autoimmune thyroid diseases, it can be considered a contributory factor.

Detection of enterovirus in the thyroid tissue of patients with graves' disease

The etiology and pathogenesis of Graves' disease (GD) are still unknown, although it is thought that both genetic and environmental factors are important. Some indirect evidence implies that a viral infection may be a possible etiologic factor in autoimmunity. The main objective of this study was to examine direct evidence of the presence of enteroviruses (EVs) in the thyroid tissue of patients with GD. Thyroid tissue from 22 patients with newly diagnosed GD was obtained by core needle biopsy, while tissue from 24 patients with chronic GD and 24 control subjects without any autoimmune thyroid diseases was collected during neck surgery. Formalin-fixed, paraffin-embedded thyroid tissue samples were examined for the presence of enterovirus capsid protein using immunohistochemistry and for enterovirus RNA using in situ hybridization. Enterovirus capsid protein was detected in 17 (37%) patients and in 4 (17%) control subjects (P = 0.103). Enterovirus RNA was identified in thyroid tissue from nine (20%) patients, but in none of the control subjects (P = 0.016). Eight (90%) of the nine virus RNA positive patients were also positive for enterovirus protein. This is the first study to analyze thyroid tissue for EVs, including patients with untreated, newly diagnosed GD. The results suggest that EVs are more frequently present in thyroid tissue of patients than controls. Further studies are indicated to explore this association to find out if a low-grade chronic enteroviral infection might be involved in the pathogenesis of GD and if this could offer new therapeutic and preventive opportunities.

Viruses and thyroiditis: an update

Viral infections are frequently cited as a major environmental factor involved in subacute thyroiditis and autoimmune thyroid diseases This review examines the data related to the role of viruses in the development of thyroiditis.

Our research has been focused on human data. We have reviewed virological data for each type of thyroiditis at different levels of evidence; epidemiological data, serological data or research on circulating viruses, direct evidence of thyroid tissue infection. Interpretation of epidemiological and serological data must be cautious as they don't prove that this pathogen is responsible for the disease. However, direct evidence of the presence of viruses or their components in the organ are available for retroviruses (HFV) and mumps in subacute thyroiditis, for retroviruses (HTLV-1, HFV, HIV and SV40) in Graves's disease and for HTLV-1, enterovirus, rubella, mumps virus, HSV, EBV and parvovirus in Hashimoto's thyroiditis. However, it remains to determine whether they are responsible for thyroid diseases or whether they are just innocent bystanders. Further studies are needed to clarify the relationship between viruses and thyroid diseases, in order to develop new strategies for prevention and/or treatment.

Radioiodine treatment for pediatric Graves' disease

BACKGROUND

Pediatric Graves' disease (GD) is an autoimmune disease in which excessive amounts of thyroid hormones circulate in the blood. Treatments for pediatric GD include antithyroid drugs (ATD), thyroidectomy and radioiodine. Up to date, the optimal therapy remains controversial.

OBJECTIVES

To assess the effects of radioiodine treatment for pediatric GD.

SEARCH STRATEGY

Studies were obtained from computerized searches of MEDLINE, EMBASE, The Cochrane Library, China National Infrastructure (CNKI) and paper collections of conferences held in Chinese.

SELECTION CRITERIA

Randomised controlled trials, controlled clinical trials and prospective cohort studies comparing the effects of radioiodine with ATD or thyroidectomy with a duration of follow-up at least one year.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality, extracted data and interviewed authors of all potentially relevant studies by telephone or electronic mail to verify randomization procedures. One author entered data into a data extraction form and another author verified the results of this procedure.

MAIN RESULTS

Two prospective controlled clinical trials involving 167 patients were included. All of them were of low quality. Radioiodine treatment versus ATD showed benefits in achieving euthyroidism (relative risk (RR) 1.70, 95% confidence interval (CI) 1.29 to 2.24). Radioiodine treatment showed a higher incidence of hypothyroidism compared with ATD (RR 6.46, 95% CI 1.16 to 35.81). No significant differences in modifying Graves' opthalmopathy (worsening or appearance) between radioiodine treatment and ATD (RR 1.30, 95% CI 0.56 to 3.00) were observed. No trial evaluated mortality, health related quality of life, economic outcomes or compliance with treatments.

AUTHORS' CONCLUSIONS

The limited results in Chinese suggest that a gland specific lower dosage of radioiodine treatment is potentially effective for pediatric GD, but a significant higher incidence of hypothyroidism compared with ATD was observed. However, we could not identify a well-designed trial to provide strong evidence for radioiodine in the treatment of pediatric GD. High-quality randomised controlled clinical trials are needed to guide treatment choice.