Interferon alpha treatment and thyroid dysfunction

Interferon autoantibodies as signals of a sick thymus

Type I interferons (IFN-I) are key immune messenger molecules that play an important role in viral defense. They act as a bridge between microbe sensing, immune function magnitude, and adaptive immunity to fight infections, and they must therefore be tightly regulated. It has become increasingly evident that thymic irregularities and mutations in immune genes affecting thymic tolerance can lead to the production of IFN-I autoantibodies (autoAbs). Whether these biomarkers affect the immune system or tissue integrity of the host is still controversial, but new data show that IFN-I autoAbs may increase susceptibility to severe disease caused by certain viruses, including SARS-CoV-2, herpes zoster, and varicella pneumonia. In this article, we will elaborate on disorders that have been identified with IFN-I autoAbs, discuss models of how tolerance to IFN-Is is lost, and explain the consequences for the host.

Prevalence, Risk Factors, and Clinical and Biochemical Characteristics of Alemtuzumab-Induced Graves Disease

OBJECTIVE

Atypical Graves disease (GD) is a common complication in multiple sclerosis (MS) patients treated with alemtuzumab. We present epidemiological, clinical, and biochemical characteristics of alemtuzumab-induced GD.

METHODS

Retrospective follow-up study of MS patients treated with alemtuzumab from 2014 to 2020, including clinical course of GD, pregnancy outcome, and thyroid eye disease (TED).

RESULTS

We enrolled 183 of 203 patients (90%, 68% women) treated with alemtuzumab at 4 hospitals in Norway. Seventy-five (41%) developed thyroid dysfunction, of whom 58 (77%) had GD. Median time from the first dose of alemtuzumab to GD diagnosis was 25 months (range, 0-64). Twenty-four of 58 GD patients (41%) had alternating phases of hyper- and hypothyroidism. Thyrotropin receptor antibodies became undetectable in 23 of 58 (40%) and they could discontinue antithyroid drug treatment after a median of 22 (range, 2-58) months. Conversely, 26 (44%) had active disease during a median follow-up of 39 months (range, 11-72). Two patients (3%) received definitive treatment with radioiodine, 6 (10%) with thyroidectomy. Nine developed TED (16%), 7 had mild and 2 moderate to severe disease. Four patients completed pregnancy, all without maternal or fetal complications. Patients who developed GD had a lower frequency of new MS relapses and MRI lesions than those without.

CONCLUSION

GD is a very common complication of alemtuzumab treatment and is characterized by alternating hyper- and hypothyroidism. Both remission rates and the prevalence of TED were lower than those reported for conventional GD. Pregnancies were uncomplicated and GD was associated with a lower risk of subsequent MS activity.

Two Cases of Chronic Central Serous Chorioretinopathy Successfully Treated with Systemic Interferon Alpha

Chronic central serous chorioretinopathy (CSCR) is a sight threatening disease that can lead to legal blindness. Verteporfin photodynamic therapy is the main treatment for chronic CSCR, however, there has been a critical worldwide shortage of verteporfin. Other medical treatments have been attempted with variable efficacy. Interferons have shown efficacy in treating uveitis and associated macular edema. We report 2 cases of treatment refractory chronic CSCR successfully treated with subcutaneous injection of interferon alpha with significant anatomical and functional improvement. To our knowledge, this is the first report observing the therapeutic potential of systemic interferon alpha in the treatment of chronic CSCR. A large randomized controlled clinical trial would help to better evaluate the safety and efficacy of systemic PEG-IFNα2a in treating chronic CSCR, and further define the optimal dose, treatment interval and duration.

Association of interferon-based therapy with risk of autoimmune diseases in patients with chronic hepatitis C virus infection: A population-based Taiwanese cohort study

Background

Interferon in combination with ribavirin has been the standard of care for chronic hepatitis C virus infection (HCV) for the past few decades. However, its effect on the risk of autoimmune diseases (ADs) among patients with HCV infection remains unclear. We assessed the potential association between interferon-based therapy (IBT) and AD risk in patients with HCV infection.

Methods

This retrospective cohort study identified patients diagnosed with HCV infection between January 1, 2006, and December 31, 2015, from Taiwan’s National Health Insurance Research Database. In total, 16,029 patients with HCV infection who received IBT and 141,214 patients with HCV infection who did not receive IBT were included. Both cohorts were followed up to assess the development of ADs. Hazard ratios (HRs) were calculated using the Cox proportional hazards regression model, which was adjusted for potential confounders.

Results

The median follow-up period for IBT and non-IBT users was 4.53 and 3.34 years, respectively. No significant difference in the risk of overall ADs (adjusted HR [aHR]: 0.96, 95% confidence interval [CI]: 0.81–1.14) or systemic ADs (aHR: 0.88, 95% CI: 0.71–1.10) was noted during the study period. However, a slight increase in the risk of organ-specific ADs was noted among IBT users (incidence rate ratio: 1.33, 95% CI: 1.02–1.72). Furthermore, analysis of AD subgroups revealed a significant increase in the risks of Graves’ disease (aHR: 6.06, 95% CI: 1.27–28.8) and Hashimoto’s thyroiditis (aHR 1.49, 95% CI 1.01–2.21) among IBT users.

Conclusions

IBT use increases the risk of autoimmune thyroid diseases (Hashimoto’s thyroiditis and Graves’ disease) in patients with HCV infection to a greater extent than non-IBT use.

Dual versus triple therapy in treatment of hepatitis C virus (HCV)

BACKGROUND

The goal of HCV treatment is eradication of the virus to prevent complications associated with the disease and decrease all-cause mortality. This work compared sustained viral response (SVR) 12 weeks after end of treatment of chronic HCV patients with different treatment regimens, namely 4 regimens. Two hundred treatment naive chronic HCV patients were selected and divided into 4 equal groups as follows: group A received pegylated interferon (peg IFN) and ribavirin (RBV); group B received peg IFN, RBV, and sofosbuvir (SOF); group C received RBV and SOF; group D received SOF, daclatasvir (DCV), and RBV.

RESULTS

The sustained viral response after 12 months of treatment is 57.23%, 72.09%, 64.40%, and 96.42% of patients in groups A, B, C, and D, respectively. Hence, group D regimen showed the best results.

CONCLUSION

SOF and DCV and RBV have the highest SVR12 and least side effects compared to other treatment regimens. Although group D patients initially had poor pretreatment investigations relative to other groups, they proved to have the highest tolerability to this regimen. Such findings hold promising line of treatment and better prognosis even for chronic HCV patients with poor liver condition.

Low MICA Gene Expression Confers an Increased Risk of Graves' Disease: A Mendelian Randomization Study

Background: Expression of natural killer group 2 member D (NKG2D) ligand (NKG2DL) plays a major role as a "danger signal" on stressed cells to promote removal of the latter by NKG2D-expressing cytotoxic lymphocytes. NKG2DL expression has been found in peripheral immune cells as well, such as in macrophages; however, the effect of this expression is yet to be determined. Methods: We determined instrumental variables (IVs; R² <0.01 in linkage disequilibrium), explaining the major variance in major histocompatibility complex class I chain-related protein A (MICA) and B (MICB) gene expression levels from the expression-quantitative trait locus (eQTL) of NKG2DLs based on the RNA-seq analysis of peripheral blood mononuclear cells (PBMCs) from 381 Japanese. Simultaneously, the target outcomes were filtered by PheWAS from 58 health risks, using a community-based cohort study composed of 44,739 Japanese residents. Finally, we estimated the causal effect of gene expression levels on the outcomes using the Mendelian randomization approach. Results: We determined nine and four IVs, explaining 87.6% and 33.0% of MICA and MICB gene expression levels, respectively. In the association test, we identified 10 or 13 significant outcomes associated with the MICA or MICB eQTLs, respectively, as well as the causal effect of MICA expression on Graves' disease (GD) (p = 4.2 × 10^-3; odds ratio per 1 S.D. difference in the expression: 0.983 [confidence interval: 0.971-0.995]), using the weighted median estimator, without significant pleiotropy (p > 0.05), and the results were consistent across the sensitivity analyses. Conclusions: Our study provide novel evidence associating NKG2DL expression with GD, an autoimmune thyroiditis; direction of the effect indicated the immunoregulatory role of MICA expression in PBMCs, suggesting the importance of further functional assays in inflammatory diseases.

Programmable System of Cas13-Mediated RNA Modification and Its Biological and Biomedical Applications

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas13 has drawn broad interest to control gene expression and cell fate at the RNA level in general. Apart from RNA interference mediated by its endonuclease activity, the nuclease-deactivated form of Cas13 further provides a versatile RNA-guided RNA-targeting platform for manipulating kinds of RNA modifications post-transcriptionally. Chemical modifications modulate various aspects of RNA fate, including translation efficiency, alternative splicing, RNA–protein affinity, RNA–RNA interaction, RNA stability and RNA translocation, which ultimately orchestrate cellular biologic activities. This review summarizes the history of the CRISPR-Cas13 system, fundamental components of RNA modifications and the related physiological and pathological functions. We focus on the development of epi-transcriptional editing toolkits based on catalytically inactive Cas13, including RNA Editing for Programmable A to I Replacement (REPAIR) and xABE (adenosine base editor) for adenosine deamination, RNA Editing for Specific C-to-U Exchange (RESCUE) and xCBE (cytidine base editor) for cytidine deamination and dm⁶ACRISPR, as well as the targeted RNA methylation (TRM) and photoactivatable RNA m⁶A editing system using CRISPR-dCas13 (PAMEC) for m⁶A editing. We further highlight the emerging applications of these useful toolkits in cell biology, disease and imaging. Finally, we discuss the potential limitations, such as off-target editing, low editing efficiency and limitation for AAV delivery, and provide possible optimization strategies.

Thyroid dysfunction is associated with the loss of hepatitis B surface antigen in patients with chronic hepatitis B undergoing treatment with α-interferon

Objective

To investigate the influence of thyroid dysfunction on the antiviral efficacy of α-interferon in adult patients with chronic hepatitis B (CHB).

Methods

We performed a retrospective study of 342 patients with CHB who underwent interferon treatment for >12 weeks. Patients with thyroid dysfunction before or during treatment were defined as the thyroid dysfunction group (n = 141) and those with normal thyroid function were defined as the normal thyroid function group (n = 201). The prevalences of hepatitis B virus (HBV) DNA undetectability, low hepatitis B surface antigen (HBsAg) titre (<250 IU/mL), HBsAg loss, and hepatitis B envelope antigen loss were compared.

Results

During interferon treatment, 69 of 270 (25.6%) participants with normal thyroid function at baseline developed thyroid dysfunction, whereas 11 of 72 (15.3%) with thyroid dysfunction at baseline regained normal thyroid function. The thyroid dysfunction group had significantly higher prevalences of low HBsAg titre (29.8% vs. 18.9%) and HBV DNA undetectability (66.0% vs. 40.3%). Multivariate logistic regression analysis showed that thyroid dysfunction was associated with HBsAg loss (odds ratio 4.945, 95% confidence interval 1.325–18.462).

Conclusions

These results suggest that thyroid dysfunction is not an absolute contraindication, but is associated with HBsAg loss, in patients with CHB undergoing α-interferon treatment.

The clinical role of interferon alpha in Philadelphia-negative myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell malignancies. Chronic inflammation and a dysregulated immune system are central to the pathogenesis and progression of MPNs. Interferon alpha (IFNα) was first used for the treatment of MPNs approximately 40 years ago. It has significant antiviral effects and plays a role in anti-proliferative, pro-apoptotic, and immunomodulatory responses. IFNα is an effective drug that can simultaneously induce significant rates of clinical, hematological, molecular, and histopathological responses, suggesting that the disease may be cured in some patients. However, its frequent dosage and toxicity profile are major barriers to its widespread use. Pegylated IFNα (peg-IFNα), and more recently, ropeginterferon alpha-2b (ropeg-IFNα-2b), are expected to overcome these drawbacks. The objective of this article is to discuss the clinical role of IFNα in Philadelphia-negative MPNs through a review of recent studies. In particular, it is expected that new IFNs, such as peg-IFNα and ropeg-IFNα-2b, with lower rates of discontinuation due to fewer adverse effects, will play important clinical roles.

Prevalence of Hypothyroidism in Patients With Erdheim-Chester Disease

IMPORTANCE

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis affecting multiple organs and commonly caused by somatic pathogenic variants in BRAF V600E and mitogen-activated protein kinase genes. Clinical features of ECD result from histiocytic involvement of various tissues; while endocrine involvement in ECD occurs frequently, the prevalence of central or primary hypothyroidism has not been thoroughly investigated.

OBJECTIVE

To assess hypothalamus-pituitary-thyroid (HPT) dysfunction in patients with ECD.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 61 patients with ECD who were enrolled in a natural history study at a tertiary care center between January 2011 and December 2018. ECD was diagnosed on the basis of clinical, genetic, and histopathological features. Data were analyzed in March 2020.

EXPOSURE

Diagnosis of ECD.

MAIN OUTCOMES AND MEASURES

Main outcome was the prevalence of thyroid dysfunction in adults with ECD compared with community estimates. Patients underwent baseline evaluation with a thyroid function test, including thyrotropin, free thyroxine (fT4), and total thyroxine (T4), and sellar imaging with magnetic resonance imaging or computed tomography scan. The association of HPT dysfunction was assessed for differences in age, sex, body mass index, BRAF V600E status, high sensitivity C-reactive protein level, sellar imaging, and pituitary hormonal dysfunction.

RESULTS

A total of 61 patients with ECD (46 [75%] men; mean [SD] age, 54.3 [10.9] years) were evaluated. Seventeen patients (28%) had hypothyroidism requiring levothyroxine therapy. The prevalence of both central and primary hypothyroidism were higher than community estimates (central hypothyroidism: 9.8% vs 0.1%; odds ratio, 109.0; 95% CI, 37.4-260.6; P < .001; primary hypothyroidism: 18.0% vs 4.7%; OR, 4.4; 95% CI, 2.1-8.7; P < .001). Patients with hypothyroidism (both primary and central), compared with patients with euthyroidism, had higher body mass index (median [interquartile range] 31.4 [28.3-38.3] vs 26.7 [24.4-31.9]; P = .004) and a higher prevalence of panhypopituitarism (7 [47%] vs 3 [7%]; P < .001). Among patients with hypothyroidism, those with central hypothyroidism, compared with patients with primary hypothyroidism, had a lower mean (SD) body mass index (28.3 [2.6] vs 36.3 [5.9]; P = .007) and higher frequencies of abnormal sellar imaging (5 [83%] vs 3 [27%]; P = .050) and panhypopituitarism (5 [83%] vs 3 [27%]; P = .050).

CONCLUSIONS AND RELEVANCE

In this cohort study, a higher prevalence of central and primary hypothyroidism was identified in patients with ECD compared with the community. There should be a low threshold for testing for hypothyroidism in patients with ECD, and treatment should follow standard guidelines.

CONVERSION OF HYPOTHYROIDISM TO HYPERTHYROIDISM: A RARE CLINICAL PHENOMENON

Objective

We present a patient with long standing hypothyroidism who developed hyperthyroidism secondary to Graves disease. Recognition of this disease phenomenon is crucial to ensure prompt diagnosis and close follow-up.

Methods

The patient was evaluated with thyroid function testing and thyroid antibody testing. Further evaluation included ophthalmologic examination and radioactive iodine uptake imaging.

Results

A 56-year-old female with past medical history of human immunodeficiency virus, hepatitis C infection, and hypothyroidism presented for evaluation of thyroid disease. She had been off of levothyroxine for the last 8 months due to biochemical findings of thyrotoxicosis. Her family history was significant for hyperthyroidism and hypothyroidism. Laboratory tests were consistent with hypothyroidism so levothyroxine was restarted. Physical exam showed lid lag and proptosis. Ophthalmologic evaluation found bilateral 23 mm proptosis. Additional lab testing was positive for thyroid peroxidase antibody and thyroid stimulating immunoglobulin. Following levothyroxine use, the patient developed subclinical hyperthyroidism and thyroid replacement was stopped. The patient remained euthyroid for 1 year off of levothyroxine. Following 1 year, she developed mild hyperthyroidism with increased radioactive iodine uptake. She was placed on propranolol for symptomatic relief. Months later, thyroid function testing normalized.

Conclusion

In Graves disease, hypothyroidism and conversion of hypothyroidism to hyperthyroidism are rare, yet important to recognize, clinical phenomenon. The stimulatory and inhibitory properties of thyroid-stimulating hormone receptor antibodies are speculated to play a role in individuals with alternating hypothyroidism and hyperthyroidism. These individuals can present a diagnostic and therapeutic challenge. Clinicians must maintain a high clinical suspicion for this disease entity.

Safety of systemic treatments for Behçet's syndrome

INTRODUCTION

Treatment of Behçet's syndrome (BS) is aimed at controlling all symptoms of such a complex disorder, ensuring a good quality of life and preventing life-threatening complications. A better understanding of the pathogenic role of different chemokines has improved our knowledge of BS and elicited a more specific use of therapies currently available, minimizing the burden of potential side-effects related to treatment.

AREAS COVERED

This work aims to provide a detailed overview of the safety profile for current therapies available in the treatment of BS, focusing on the main side-effects, toxicity and contraindications.

EXPERT OPINION

The greatest experience in the management of BS has been achieved with the employment of monoclonal anti-tumor necrosis factor antibodies which have been advocated for BS refractory manifestations. Moreover, interleukin-1 inhibitors have proven to be effective as well as safe, despite escalation of their dosage, especially to manage the most severe and difficult-to-treat ocular manifestations. However, general treatment of BS patients remains awkward as protean clinical features may respond differently to the same treatment or even worsen. Therefore, patients' safety for therapies used in BS promotes the implementation of precision medicine, which could help targeting accurately the pathogenetic mechanisms concealed behind specific clinical phenotypes.

Thyroid Function in Children with Down Syndrome in the Polish Population: A Case-Control Study

BACKGROUND

Patients with subclinical thyroid disease have few or no clinical symptoms of thyroid dysfunction and thus, laboratory diagnosis is needed. In this context, the objective of the current study was to analyze the prevalence rate and pattern of thyroid function in children with Down syndrome in the Polish population.

METHODS

A total of 30 children, aged 6-12 years, with cytogenetically confirmed Down syndrome were studied. The control group included 27 children.

RESULTS

Of the 30 patients with Down syndrome, 14 (46.7%) had abnormal thyroid profiles. Mean thyroid-stimulating hormone (TSH) and fT4 concentrations in children with Down syndrome were found to be significantly increased compared with the controls (4.30 ± 1.9 µIU/mL, 95% CI: 3.55-5.04 µIU/mL vs. 3.10 ± 1.47 µIU/mL, 95% CI: 2.52-3.68 µIU/mL, P = 0.013, 95% CI: 0.26-2.14, and 1.33 ± 0.23 ng/dL, 95% CI: 1.25-1.42 vs. 1.19 ± 0.14 ng/dL, 95% CI: 1.13-1.25, P = 0.008, 95% CI: 0.04-0.24, respectively). In Down syndrome, subclinical hypothyroidism was recognized in 10 children (33.3%) (high TSH and normal fT4 and fT3 levels). Two children (6.67%) had evident hypothyroidism (high TSH and low fT4). In the control group, subclinical hypothyroidism was diagnosed in four (14.8%) children.

CONCLUSION

Children with Down syndrome may have increased secretion of TSH, even when thyroid hormone and autoantibodies are normal, suggesting that an isolated increase in TSH does not predispose the patient to the development of thyroid disease. We also recommend that all patients with Down syndrome should be screened for thyroid dysgenesis, since they have thyroid dysfunction more frequently as compared to the general healthy population.

ZBED2 is an antagonist of interferon regulatory factor 1 and modifies cell identity in pancreatic cancer

Lineage plasticity is a prominent feature of pancreatic ductal adenocarcinoma (PDA) cells, which can occur via deregulation of lineage-specifying transcription factors. Here, we show that the zinc finger protein ZBED2 is aberrantly expressed in PDA and alters tumor cell identity in this disease. Unexpectedly, our epigenomic experiments reveal that ZBED2 is a sequence-specific transcriptional repressor of IFN-stimulated genes, which occurs through antagonism of IFN regulatory factor 1 (IRF1)-mediated transcriptional activation at cooccupied promoter elements. Consequently, ZBED2 attenuates the transcriptional output and growth arrest phenotypes downstream of IFN signaling in multiple PDA cell line models. We also found that ZBED2 is preferentially expressed in the squamous molecular subtype of human PDA, in association with inferior patient survival outcomes. Consistent with this observation, we show that ZBED2 can repress the pancreatic progenitor transcriptional program, enhance motility, and promote invasion in PDA cells. Collectively, our findings suggest that high ZBED2 expression is acquired during PDA progression to suppress the IFN response pathway and to promote lineage plasticity in this disease.

Anticancer Drug-induced Thyroid Dysfunction

Cancer immunotherapy and targeted therapy, though less toxic than conventional chemotherapy, can increase the risk of thyroid dysfunction. Immune checkpoint inhibitors render the cancer cells susceptible to immune destruction, but also predispose to autoimmune disorders like primary hypothyroidism as well as central hypothyroidism secondary to hypophysitis. Tyrosine kinase inhibitors act by blocking vascular endothelial growth factor receptors and their downstream targets. Disruption of the vascular supply from the inhibition of endothelial proliferation damages not only cancer cells but also organs with high vascularity like the thyroid. Interferon-α, interleukin-2 and thalidomide analogues can cause thyroid dysfunction by immune modulation. Alemtuzumab, a monoclonal antibody directed against the cell surface glycoprotein CD52 causes Graves' disease during immune reconstitution. Metaiodobenzylguanidine, combined with 131-iodine, administered as a radiotherapeutic agent for tumours derived from neural crest cells, can cause primary hypothyroidism. Bexarotene can produce transient central hypothyroidism by altering the feedback effect of thyroid hormone on the pituitary gland. Thyroid dysfunction can be managed in the usual manner without a requirement for dose reduction or discontinuation of the implicated agent. This review aims to highlight the effect of various anticancer agents on thyroid function. Early recognition and appropriate management of thyroid disorders during cancer therapy will help to improve treatment outcomes.

Autoimmune Thyroid Disease in Specific Genetic Syndromes in Childhood and Adolescence

Autoimmune thyroid disease (ATD) is the most frequent cause of acquired thyroid dysfunction, most commonly presenting either as Hashimoto's thyroiditis or Graves' Disease. Hashimoto's thyroiditis is characterized by the presence of thyroid-specific autoantibodies, more commonly anti-thyroperoxidase antibodies in the serum and the typical inhomogeneous echostructure of the thyroid on a thyroid ultrasound examination. Hashimoto's thyroiditis can for a long time be accompanied by normal thyroid function and hypothyroidism can only progressively be established. Graves' disease is much less frequent in childhood and adolescence and presents with overt hyperthyroidism. After the onset of puberty, ATD affects females with a higher incidence than males, while during the prepubertal period there is not such a clear preponderance of affected females. ATD can occur either isolated or in the context of other autoimmune disorders, such as type 1 Diabetes mellitus (T1D), celiac disease, alopecia areata, vitiligo, etc. Especially at the pediatric age, a higher incidence of ATD is also observed in the context of specific genetic syndromes, such as trisomy 21 (Down syndrome), Klinefelter syndrome, Turner syndrome, or 22q11.2 deletion syndrome. Nevertheless, although thyroid dysfunction may also be observed in other genetic syndromes, such as Prader-Willi or Williams syndrome, the thyroid dysfunction in these syndromes is not the result of thyroid autoimmunity. Interestingly, there is emerging evidence supporting a possible link between autoimmunity and RASopathies. In this review article the incidence, as well as the clinical manifestation and accompanied pathologies of ATD in specific genetic syndromes will be presented and regular follow-up for the early identification of the disorder will be proposed.

Regulation of TSHR Expression in the Thyroid and Thymus May Contribute to TSHR Tolerance Failure in Graves' Disease Patients via Two Distinct Mechanisms

Graves' disease (GD) involves the presence of agonistic auto-antibodies against the thyrotropin receptor (TSHR), which are responsible for the clinical symptoms. While failure of TSHR tolerance is central to GD pathogenesis, the process leading to this failure remains poorly understood. Two mechanisms intimately linked to tolerance have been proposed to explain the association of SNPs located in TSHR intron 1 to GD: (1) differential alternative splicing in the thyroid; and (2) modulation of expression in the thymus. To elucidate the relative contribution to these two mechanisms to GD pathogenesis, we analyzed the level of full-length and ST4 and ST5 isoform expression in the thyroid (n = 49) and thymus (n = 39) glands, and the influence of intron 1-associated SNPs on such expression. The results show that: (1) the level of flTSHR and ST4 expression in the thymus was unexpectedly high (20% that of the thyroid); (2) while flTSHR is the predominant isoform, the levels are similar to ST4 (ratio flTSHR/ST4 = 1.34 in the thyroid and ratio flTSHR/ST4 in the thymus = 1.93); (3) next-generation sequencing confirmed the effect of the TSHR intron 1 polymorphism on TSHR expression in the thymus with a bias of 1.5 ± 0.2 overexpression of the protective allele in the thymus compared to the thyroid; (4) GD-associated intron 1 SNPs did not influence TSHR alternative splicing of ST4 and ST5 in the thyroid and thymus; and (5) three-color confocal imaging showed that TSHR is associated with both thymocytes, macrophages, and dendritic cells in the thymus. Our findings confirm the effect of intron 1 polymorphisms on thymic TSHR expression and we present evidence against an effect on the relative expression of isoforms. The high level of ST4 expression in the thymus and its distribution within the tissue suggest that this would most likely be the isoform that induces central tolerance to TSHR thus omitting most of the hinge and transmembrane portion. The lack of central tolerance to a large portion of TSHR may explain the relatively high frequency of autoimmunity related to TSHR and its clinical consequence, GD.

The antigenic link between thyroid autoimmunity and breast cancer

The association between breast cancer and benign thyroid disorders, in particular thyroid autoimmunity, has been debated for decades. Autoantibodies to thyroid peroxidase, the hallmark of thyroid autoimmunity, have a higher prevalence among patients with breast cancer compared with the general population. Furthermore a correlation between their positivity and a better prognosis of breast cancer was found in several independent small-scale studies, even if such observation was not confirmed in a subsequent retrospective study conducted on the largest patient cohort to date. The thyroid and mammary glands present several biological similarities, therefore the hypothesis of an immune response to shared thyroid/breast antigens could in part explain the association between thyroid autoimmunity and breast cancer. The sodium iodide symporter is expressed in both glands, however it seems unlikely to be the key common antigen, considering that autoantibodies targeting it are rare. Instead thyroid peroxidase, one of the major thyroid autoantigens, is also expressed in breast tissue and therefore represents the main antigenic link between thyroid autoimmunity and breast cancer. Furthermore lactoperoxidase, an enzyme of the same family that shares structural similarities with thyroid peroxidase, is expressed in neoplastic breast cells and is responsible for the cross-reactivity with some autoantibodies to thyroid peroxidase. Novel strategies for the diagnosis and treatment of breast cancer might take advantage of the antigenic link between thyroid and breast tissues.

Effectiveness and safety of interferon α2a as an add-on treatment for refractory Behçet's uveitis

Objective:

The objective of this study was to investigate the effectiveness and safety of interferon (IFN) α2a as an add-on treatment for refractory Behçet’s uveitis (BU).

Methods:

In this retrospective cohort study, 30 refractory BU patients who received IFNα2a treatment in Peking Union Medical College Hospital between February 2015 and June 2018 were consecutively included. IFNα2a was used mainly as an add-on treatment for BU patients who underwent relapse under corticosteroids and conventional immunosuppressive agents. The primary outcome was treatment success rate before and after initiation of IFNα2a. Changes in ocular relapse rates, disease activity, corticosteroid- and immunosuppressant-sparing effects, as well as side effects were secondary outcomes.

Results:

A total of 30 patients (27 males and 3 females) with a mean age of 30.5 ± 8.7 years were included. Twenty-one patients (70%) were treated with at least 2 immunosuppressive agents before the initiation of IFNα2a. Treatment success was achieved in 26 patients (86.7%), and the median uveitis relapse rate decreased from 7.3 (range 2–12) to 0 (range 0–6) per patient-year (p = 0.000002) during a mean follow-up of 21.7 ± 7.5 months, corticosteroids were lowered in 25 cases (83.3%) and completely withdrawn in four (13.3%). In addition, immunosuppressive agents were reduced in number and dosage in 22 (73.3%) and 29 patients (96.7%), respectively, and were completely withdrawn in 12 cases (40%). No severe adverse events were observed and serum autoantibodies remained negative during the treatment of IFNα2a.

Conclusion:

IFNα2a is effective and relatively safe in refractory BU, with significant steroid- and immunosuppressant-sparing effects.

Long-term outcomes and risk factors of thyroid dysfunction during pegylated interferon and ribavirin treatment in patients with chronic hepatitis C infection in Taiwan

BACKGROUND

This study aimed to investigate the occurrence and risk factors of thyroid dysfunction (TD) in patients with chronic hepatitis C (CHC) infection in Taiwan.

METHODS

The data in this study were obtained from the Taiwan National Health Insurance Research (Taiwan NHIR) database between 2001 and 2013. CHC patients treated with pegylated interferon/ribavirin (PEG-IFN/RBV) were enrolled as case patients, and nontreated CHC patients were enrolled as controls and were matched at a control:case ratio of 3:1 by index date, age (± 3 years), and sex. We compared the cumulative incidence of TD between the cohorts at follow-up until 2013.

RESULTS

During the study period, 3810 cases and 9393 controls were included in the study. Among the study subjects, 173 (4.5%) case patients and 244 (2.6%) controls were diagnosed with TD during the follow-up period. The types of TD were hypothyroidism (42.9%), hyperthyroidism (31.2%), and thyroiditis (25.9%). Compared to controls during the 13-year follow-up, patients treated with PEG-IFN/RBV had a higher incidence rate of TD (P < 0.0001), as determined using the Kaplan-Meier method. Cox proportional hazards regression analysis showed that female sex (adjusted hazard ratio (HR): 1.49; 95% confidence interval (CI): 1.23-1.75; P < 0.001), treatment with PEG-IFN/RBV (HR: 1.68; 95% CI: 1.38-2.06; P < 0.001), hyperlipidemia (HR: 1.38; 95% CI: 1.12-1.71; P < 0.001), and past history of goiter (HR: 6.40; 95% CI: 5.00-8.18; P < 0.001) were independent predictors for the development of TD.

CONCLUSIONS

PEG-IFN/RBV treatment may be an independent risk factor for thyroid dysfunction among patients with hepatitis C virus (HCV) infection. Monitoring thyroid function keenly during PEG-IFN/RBV therapy in patients with chronic HCV infection is recommended for clinicians, especially for female patients and for patients with a history of hyperlipidemia and goiter.

IRF7 Gene Variations Confer Susceptibility to Autoimmune Thyroid Diseases and Graves' Ophthalmopathy

The objective of this study was to investigate whether IRF7 polymorphisms are associated with autoimmune thyroid diseases (AITDs). We selected three single nucleotide polymorphisms (SNPs) of IRF7, namely, rs1061501, rs1131665, and rs1061502 for genotyping using PCR-based ligase detection reaction (LDR) method in a total of 1659 participants (592 with Graves' disease, 297 with Hashimoto's thyroiditis, and 770 healthy controls). Gene-disease and genotype-clinical phenotype associations were evaluated for the three SNPs. Our results showed that the AG genotype and the minor allele G frequency of rs1131665 and rs1061502 in AITD patients were both higher than those of the controls (rs1131665: AG genotype: P = 0.017, OR = 1.968; allele G: P = 0.018, OR = 1.946; rs1061502: AG genotype: P = 0.029, OR = 1.866; allele G: P = 0.031, OR = 1.847). Subgroup analysis also showed that the AG genotype and the minor allele G frequency of rs1131665 and rs1061502 in Graves' disease patients were both higher than those of the controls (rs1131665: AG genotype: P = 0.015, OR = 2.074; allele G: P = 0.016, OR = 2.048; rs1061502: AG genotype: P = 0.034, OR = 1.919; allele G: P = 0.035, OR = 1.898). Furthermore, the allele G frequency of rs1061501 was associated with Graves' ophthalmopathy (P = 0.035, OR = 1.396). No significant difference in IRF7 polymorphisms was found between Hashimoto's thyroiditis patients and controls. Our study has revealed for the first time that IRF7 is a susceptibility gene for AITD, especially for Graves' disease and Graves' ophthalmopathy.

Iodine intake and chronic autoimmune thyroiditis: a comparative study between coastal and mainland regions in Greece

INTRODUCTION

The purpose of this study was to evaluate the relationship between iodine intake and autoimmune thyroiditis in Chios, an island located in the North East Aegean Sea, in comparison to mainland regions in South Western Greece (SWG).

MATERIALS AND METHODS

Urine iodine concentration (UIC), thyroid function (serum TSH, thyroid autoantibodies: anti-TPO and anti-Tg), and thyroid U/S were assessed in 200 subjects (150 females and 50 males) from Chios and 322 subjects (255 females and 67 males) from several mainland regions in SWG. All participants were recruited from outpatient clinics and were diagnosed as euthyroid.

RESULTS

Median UIC in Chios was significantly higher compared to SWG (136.1 vs. 104.5 μg/L, p < 0.001), indicating that both regions are iodine sufficient according to World Health Organization (WHO) criteria. The prevalence of thyroid autoimmunity was 66.5% in Chios and 27% in SWG, significantly higher in females (46.7%) than in males (26.5%). Furthermore, individuals with increased levels of thyroid autoantibodies either anti-TPO or anti-Tg (TAbs) showed increased median UIC levels compared to those / subjects / patients with normal levels (126.7 vs. 108.95 μg/L, p < 0.001). Serum TSH mean values (mIU/L) were greater in females (mean = 2.1 ± 1.41) compared to males (mean = 1.82 ± 1.26) (p = 0.04) and decreased with age.

CONCLUSIONS

In conclusion, in the present study, we clearly indicate that increased thyroid autoimmunity is positively associated with increased iodine intake, as well as with the female gender. Moreover, iodine intake and thyroid autoimmunity appear to be significantly higher in a coastal region (Chios) than in mainland Greece (SWG). Additional environmental factors, apart from iodine, should be investigated in future studies. Mean TSH values were increased in females and decreased with age. The latter is probably due to the presence of autonomous goiter in older Greek populations, as a result of long-term status of iodine deficiency in the past.

Prevalence of thyroid stimulating hormone dysfunction among sofosbuvir-treated HCV-infected patients: A real-world clinical experience

Thyroid dysfunctions occur frequently among hepatitis C virus (HCV)-infected patients. Accumulating evidence has shown the higher incidence of thyroid dysfunctions in interferon-treated patients that was previously the standard of care therapy. However, the prevalence of thyroid disorders has not been studied in the recently developed interferon-free regimens or direct-acting antiviral (DAA) drugs-treated patients. We recruited 37 patients who had just completed 6 months long sofosbuvir-based treatment, and 26 interferon-treated patients were also included in the study. Serum thyrotropin level of all participants was measured using VIDAS. We observed thyroid dysfunctions in both pegylated interferon-experienced and DAA drug-experienced patients but the prevalence of hyperthyroidism was found significantly higher in patients treated with interferon-based regimen as compared with interferon-free regimens. This high prevalence of hypothyroidism in patients with HCV posttreatment highlights the need for regular periodic screening of patients during the treatment.

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)

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.

Interferon alpha-induced non-immune thyrotoxicosis treated by plasmapheresis

Interferon-alpha (IFN-α) is an effective drug used for the treatment of chronic hepatitis C. So far its numerous side effects have been reported in the literature. It may be difficult to always put IFN-induced thyroid diseases into a single classic thyroid disease table. There are numerous atypical thyroid diseases due to IFN usage for hepatitis C virus. Herein, we present a case with a rare clinical table such as thyrotoxicosis observed following IFN-α therapy in a patient with euthyroid nodular thyroid without autoimmune thyroiditis findings and the use of therapeutic apheresis method for the treatment of disease.

ITM2A Expands Evidence for Genetic and Environmental Interaction in Graves Disease Pathogenesis

CONTEXT

Graves disease (GD) is a common autoimmune disease triggered by genetic predisposition and environmental factors. However, the mechanisms of interaction between genetic and environmental factors contributing to the development of GD remain unknown.

OBJECTIVE

We aimed to identify GD susceptibility variants and genes on Xq21.1 locus and interpret the contribution of interaction between genetic predisposition on Xq21.1 and environmental factors to GD.

DESIGN

We performed refining study on Xq21.1 in a 2-stage study and carried out expression quantitative trait locus analysis of the best association signal with GD.

SETTING AND PARTICIPANTS

A total of 4316 GD patients and 4374 sex-matched controls were collected from the Chinese Han population by cooperation with multiple hospitals.

RESULTS

We identified that rs3827440 or its linkage single nucleotide polymorphisms (SNPs) were probably the causal variant in the Xq21.1 locus, with the most substantial association with GD in our combined cohorts (P = 2.45 × 10-15). The genotypes of rs3827440 were correlated with the expression of ITM2A in monocytes and peripheral blood mononuclear cells (PBMCs) from healthy volunteers. Notably, the expression of ITM2A in monocytes after lipopolysaccharide (LPS) and interferon-γ (INF-γ) stimulation showed substantial difference among the volunteers that carried different genotypes of rs3827440 (P = 9.40 × 10-7 and P = 1.26 × 10-5 for 24 hours' LPS and INF-γ stimulation, respectively). Moreover, ITM2A expression was significantly decreased in PBMCs from untreated GD patients than that from controls.

CONCLUSION

The results suggest that ITM2A might be a susceptibility gene for GD in the Xq21.1 locus, and environmental factors, such as viral and bacterial infections, probably contribute to GD pathogenesis by interacting with the risk SNP rs3827440 mediating the regulation of ITM2A expression.

Thyroid Involvement in Hepatitis C Virus-Infected Patients with/without Mixed Cryoglobulinemia

Thyroid involvement is a common condition that can be recorded during the natural course of different systemic rheumatic diseases, including the mixed cryoglobulinemia (MC) syndrome or cryoglobulinemic vasculitis. MC is triggered by hepatitis C virus (HCV) chronic infection in the majority of cases; it represents the prototype of autoimmune-lymphoproliferative disorders complicating a significant proportion of patients with chronic HCV infection. HCV is both hepato- and lymphotropic virus responsible for a great number of autoimmune/lymphoproliferative and/or neoplastic disorders. The complex of HCV-related hepatic and extrahepatic manifestations, including MC and thyroid involvement, may be termed "HCV syndrome." Here, we describe the prevalence and clinico-serological characteristics of thyroid involvement, mainly autoimmune thyroiditis and papillary thyroid cancer, in patients with HCV syndrome with or without cryoglobulinemic vasculitis.

Prevalence of thyroid disorders in hepatitis C virus positive patients on interferon and antiviral therapy

Background:

Hepatitis C virus (HCV) infection is common worldwide. The treatment typically involves a combination of interferon-alpha (IFN-α) and ribavirin (RBV) therapy; however, the use of IFN-α is well documented to be associated with thyroid disease, the most common autoimmune disorder associated with IFN-α.

Aim:

The aim of the present study was to know the prevalence of thyroid abnormality in the HCV-positive patients on IFN and antiviral therapy.

Materials and Methods:

Fifty known HCV positive patients were enrolled for the study. All the patients were on IFN (3 million unit subcutaneously 3 times/week) and antiviral therapy (oral RBV 1000–1200 mg/day). Thyroid function tests were performed first at the start of treatment and then after 12 weeks of treatment.

Results:

13 (26%) of the patients were found to develop hypothyroidism, and 1 (2%) patient developed hyperthyroidism in the course of 12 weeks therapy.

Conclusion:

HCV patients on IFN and antiviral therapy have an effect on the thyroid gland, so these patients should be regularly screened for thyroid disorders and appropriately treated to maintain euthyroid status.

Interaction of interferon alpha therapy with thyroid function tests in the management of hepatitis C: a case report

Background

Interferon alpha is a widely used therapeutic agent in the treatment of hepatitis C virus infection. Clinical thyroid disease is seen in nearly 15 % of patients receiving interferon alpha for hepatitis C virus infection. The mechanism of thyroid dysfunction with interferon alpha is either autoimmune or inflammatory. We report a case of young woman who developed biphasic thyroid dysfunction posing a diagnostic challenge, while receiving interferon alpha treatment for hepatitis C virus infection.

Case presentation

A 29-year-old, Caucasian woman with type 1 diabetes and hepatitis C virus infection was referred with hyperthyroidism, while she was at 17 weeks of a planned 24-week course of interferon alpha therapy. A laboratory investigation revealed a thyroid stimulation hormone level of 0.005 mU/L (0.350–4.94), free thyroxine of 45.6 pmol/L (9.0–19.0) and free tri-iodothyronine of 12.6 pmol/L (2.6–5.7). She had a mild neutropenia and alanine aminotransferase at double the reference value. Her thyroid peroxidase antibody level was 497 ku/L (<5.6) and thyroid inhibitory factor 7 IU/L (>1.8 iu/l is positive). Thyroid scintigraphy with technetium99 scan confirmed a normal-sized thyroid gland with diffuse but normal overall uptake. A diagnosis of interferon alpha-triggered autoimmune hyperthyroidism as opposed to an inflammatory thyroiditis was made. She was offered radioactive iodine therapy, as thionamides were considered inappropriate in view of her liver disease and mild neutropenia. Due to our patient’s personal circumstances, radioactive iodine therapy was delayed by 8 weeks and her thyrotoxic symptoms were controlled with beta-blockers alone. A repeat thyroid function test, 4 weeks post treatment with interferon alpha, indicated spontaneous conversion to hypothyroidism with a thyroid stimulation hormone level of 100 mU/L, free thyroxine of 5.2 pmol/L and free tri-iodothyronine of 1.7 pmol/L. She subsequently received levothyroxine for 4 months only and had remained euthyroid for the last 3 months without any treatment.

Conclusions

Initial investigations favored the autoimmune nature of hyperthyroidism but follow-up of the case, interestingly, was more consistent with inflammatory thyroiditis. We propose that this can be explained either on the basis of autoimmune subacute thyroiditis or a change in the nature of thyroid stimulation hormone receptor antibody production from stimulating-type to blocking-type antibodies, with disappearance of the latter on discontinuation of interferon alpha.

SEQUENCE SIMILARITY BETWEEN THYROID SELF-PROTEIN AND HEPATITIS C VIRUS POLYPROTEIN: possible triggering mechanism of autoimmune thyroiditis

ABSTRACT Background - Exposure to viral antigens that share amino acid sequence similar with self- antigens might trigger autoimmune diseases in genetically predisposed individuals, and the molecular mimicry theory suggests that epitope mimicry between the virus and human proteins can activate autoimmune disease. Objective - The purpose of this study is to explore the possible sequence similarity between the amino acid sequences of thyroid self-protein and hepatitis C virus proteins, using databanks of proteins and immunogenic peptides, to explain autoimmune thyroid disease. Methods - Were performed the comparisons between the amino acid sequence of the hepatitis C virus polyprotein and thyroid self-protein human, available in the database of National Center for Biotechnology Information on Basic Local Alignment Search Tool. Results - The sequence similarity was related each hepatitis C virus genotype to each thyroid antigen. The similarities between the thyroid and the viral peptides ranged from 21.0 % (31 identical residues out of 147 amino acid in the sequence) to 71.0% (5 identical residues out of 7 amino acid in the sequence). Conclusion - Bioinformatics data, suggest a possible pathogenic link between hepatitis C virus and autoimmune thyroid disease. Through of molecular mimicry is observed that sequences similarities between viral polyproteins and self-proteins thyroid could be a mechanism of induction of crossover immune response to self-antigens, with a breakdown of self-tolerance, resulting in autoimmune thyroid disease.

Prevalence of Celiac Disease in Patients with Autoimmune Thyroid Disease: A Meta-Analysis

BACKGROUND

Several screening studies have indicated an increased prevalence of celiac disease (CD) among individuals with autoimmune thyroid disease (ATD), but estimates have varied substantially.

OBJECTIVE

The aim of this study was to examine the prevalence of CD in patients with ATD.

METHOD

A systematic review was conducted of articles published in PubMed Medline or EMBASE until September 2015. Non-English papers with English-language abstracts were also included, as were research abstracts without full text available when relevant data were included in the abstract. Search terms included "celiac disease" combined with "hypothyroidism" or "hyperthyroidism" or "thyroid disease." Fixed-effects inverse variance-weighted models were used. Meta-regression was used to examine heterogeneity in subgroups.

RESULTS

A pooled analysis, based on 6024 ATD patients, found a prevalence of biopsy-confirmed CD of 1.6% [confidence interval (CI) 1.3-1.9%]. Heterogeneity was large (I(2) = 70.7%). The prevalence was higher in children with ATD (6.2% [CI 4.0-8.4%]) than it was in adults (2.7%) or in studies examining both adults and children (1.0%). CD was also more prevalent in hyperthyroidism (2.6% [CI 0.7-4.4%]) than it was in hypothyroidism (1.4% [CI 1.0-1.9%]).

CONCLUSIONS

About 1/62 patients with ATD have biopsy-verified CD. It is argued that patients with ATD should be screened for CD, given this increased prevalence.

Implications of prognostic variables in the assessment of autoimmunity in hepatitis C patients receiving interferon therapy

Systematic administration of interferon-alpha (INF-alpha) is considered as the backbone of HCV therapy since 1991. Interferon (IFN) therapy can cause vasculitis, glomerulonephritis, cryoglobulinemia and certain other autoimmune diseases such as sialoadentitis, lichen planus and thyroiditis. Related to the factors of interferons, extensively studied gland is thyroid gland. A strong association was observed between thyroid disease and HCV patient when they were exposed to IFN therapy. Vitamin D, malondialdehyde (MDA), thyroid hormones and auto antibodies were biochemically assessed from the venous blood of seventy five HCV patients and fifty healthy controls. The results of all parameters were analyzed by independent sample t-test. The results of the study demonstrated a clear picture that the levels of vitamin D decreased as compared to control but increases in case of MDA. The levels of antibody titer represent that thyroglobulin-antibody (TGAb) thyroid peroxidase-antibody (TPOAb) as well as thyroid stimulating hormone receptor-antibody (TSHRAb) were raised in the patients suffering from HCV with thyroid dysfunction as compared to control. Similarly, the levels of thyroid hormones were also elevated in the HCV patients. Antibodies generated against thyroidal enzymes leads to impaired function of these enzymes thus causing decreased synthesis of thyroid hormones. As exogenous INF triggers the release of cytokines that mediate the recruitment of immune cells with increased production of inflammatory markers lead to production of lytic granules which have direct toxic action on thyroid cells and ultimately increased lipid peroxidation of thyrocytes. The results of the present study clearly demonstrated that the decreased levels of vitamin D in HCV patients receiving IFN therapy were responsible to induce autoimmunity against thyroid gland and adjutant therapy may be helpful to alleviate the possible thyroid disorders.

Acute pancreatitis associated with pegylated interferon-alpha-2a therapy in chronic hepatitis C

Chronic hepatitis C virus (HCV) infection is a major cause of liver cirrhosis and hepatocellular carcinoma. Combination therapy of pegylated interferon-alpha (PEG-IFN-α) and ribavirin (RBV) is a current standard treatment for chronic HCV infection in Korea, which has considerable adverse effects. Acute pancreatitis is a rare complication of PEG-IFN-α administration. We report a case of a 62-year-old female who experienced acute pancreatitis after 4 weeks of PEG-IFN-α-2a and RBV combination therapy for chronic HCV infection. The main cause of the acute pancreatitis in this case was probably PEG-IFN-α rather than RBV for several reasons. A few cases have been reported in which acute pancreatitis occurred during treatment with PEG-IFN-α-2b. This is the first report of acute pancreatitis associated with PEG-IFN-α-2a in Korea.

Hepatitis C virus infection and thyroid autoimmune disorders: A model of interactions between the host and the environment

The hepatitis C virus (HCV) infection is an important public health problem and it is associated with hepatic and extrahepatic manifestations. Autoimmune thyroid diseases are common in HCV infected patients and the standard interferon-based treatment is associated with an increase of the immune-mediated thyroid damage. Recent evidence in the literature analyzed critical points of the mechanisms of thyroid damage, focusing on the balance between the two sides of the interaction: The environment (virus infection with potential cross-reaction) and the host (susceptibility genes with consistent immune response). The spectrum of antiviral treatment for chronic HCV infection is rapidly expanding for the development of dual o triple therapy. The availability of interferon-free combined treatment with direct antiviral agents for HCV is very promising, in order to ameliorate the patient compliance and to reduce the development of thyroid autoimmunity.

Thyroid dysfunction in Chinese hepatitis C patients: Prevalence and correlation with TPOAb and CXCL10

AIM: To investigate the relationship among pretreatment serum CXC chemokine ligand 10 (CXCL10), thyroid peroxidase antibody (TPOAb) levels and thyroid dysfunction (TD) in Chinese hepatitis C patients.

METHODS: One hundred and thirty-nine treatment-naive genotype 1 chronic hepatitis C patients with no history of TD or treatment with thyroid hormones were enrolled in this study. Patients underwent peginterferon alfa-2a/ribavirin (PegIFNα-2a/RBV) treatment for 48 wk, followed by detection of clinical factors at each follow-up point. Hepatitis C virus (HCV) antibodies were analyzed using microsomal chemiluminescence, and serum HCV RNA was measured by real-time PCR assay at 0, 4, 12, 24 and 48 wk after the initiation of therapy and 24 wk after the end of therapy. To assess thyroid function, serum thyroid stimulating hormone (TSH), free thyroxine (FT4), free triodothyronine (FT3) and TPOAb/thyroglobulin antibody (TGAb) levels were determined using chemiluminescent immunoassays every 3 mo. Serum CXCL10 levels were determined at baseline.

RESULTS: The prevalence of TD was 18.0%. Twenty-one (84.0%) out of twenty-five patients exhibited normal thyroid function at week 24 after therapy. The rate of sustained virological response to PegIFNα-2a/RBV in our study was 59.0% (82/139), independent of thyroid function. Pretreatment serum CXCL10 levels were significantly increased in patients with euthyroid status compared with patients with TD (495.2 ± 244.2 pg/mL vs 310.0 ± 163.4 pg/mL, P = 0.012). Patients with TD were more frequently TPOAb-positive than non-TD (NTD) patients (24.2% vs 12.3%, P = 0.047) at baseline. Three of the one hundred and fifteen patients without TPOAb at baseline developed TD at the end of treatment (37.5% vs 2.6%, P = 0.000). Female patients exhibited an increased risk for developing TD compared with male patients (P = 0.014).

CONCLUSION: Lower pretreatment serum CXCL10 levels are associated with TD, and TD prevalence increases in female patients and patients who are positive for TPOAb at baseline.

Association of IRF8 gene polymorphisms with autoimmune thyroid disease

BACKGROUND

The occurrence of autoimmune thyroid disease (AITD) is known to have a major adverse effect on interferon (INF)-α treatment. The genetic variant of the INF regulatory factor 8 (IRF8), a type 1 INF regulator, is associated with susceptibility to systemic lupus erythematosus and multiple sclerosis. In this study, we investigated possible associations of the IRF8 polymorphisms, rs17445836 and rs2280381, with AITD in an ethnic Chinese population.

MATERIAL AND METHODS

In total, 278 patients with Graves' disease (GD) and 55 patients with Hashimoto's thyroiditis (HT), and 252 healthy controls were enrolled. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing were used for genotyping.

RESULTS

Significantly lower frequencies of the GA genotype and A allele of rs17445836 were found in the HT group than in the control group (P = 0·028, odds ratio (OR) = 4·71 and P = 0·022, OR = 4·40, respectively). Both rs17445836 and rs2280381 were associated with the presence of an antimicrosomal antibody (AmiA), and rs2280381 was also associated with the presence of an antithyroglobulin antibody (ATA) in AITD. Moreover, rs17445836 was associated with the level of AmiA in AITD.

CONCLUSIONS

rs17445836 of IRF8 is a possible genetic variant associated with the development of HT. rs17445836 was associated with the production of thyroid antibody, and the GG genotype of rs17445836 was associated with a higher AmiA titre than the GA genotype.

Autoantibodies in chronic hepatitis C: A clinical perspective

Non-organ-specific autoantibodies and thyroid autoantibodies have been frequently found in chronic carriers of hepatitis C virus (HCV). With respect to endomysial antibodies and tissue transglutaminase, it is controversial whether the prevalence of gluten-related seromarkers is higher in patients with HCV. In such cases, in addition to acknowledging any currently existing autoimmune disease, recognizing the risk of the patient developing an autoimmune disease during interferon (IFN)-based treatment must be a principle concern. From a clinical point-of-view, the presence of autoantibodies arouses suspicion that an autoimmune disease may be present or may be precipitated by IFN-based HCV treatment. In this paper, we review the prevalence of autoantibodies in individuals with hepatitis C, the clinical significance of these autoantibodies, and the approach recommended for such situations.

Role of genetic and non-genetic factors in the etiology of Graves' disease

In spite of the advancements in understanding the pathogenic mechanisms of Graves' disease (GD), its ultimate cause remains elusive. The majority of investigators agree that GD is likely a multifactorial disease, due to a complex interplay of genetic and non-genetic factors that lead to the loss of immune tolerance to thyroid antigens and to the initiation of a sustained autoimmune reaction. Twin and family studies support a role of genetic factors, among which the HLA complex, CD40, CTLA-4, PTPN22, FCRL3, thyroglobulin, and the TSH receptor may be involved. Among non-genetic factors, iodine, infections, psychological stress, gender, smoking, thyroid damage, vitamin D, selenium, immune modulating agents, and periods of immune reconstitution may contribute the development of the diseases. Here we review in detail the respective role of genetic and non-genetic factors in the etiology of GD, taking advantage of the great bulk of data generated especially over the past 30 years.

Thyroid autoimmunity as a window to autoimmunity: An explanation for sex differences in the prevalence of thyroid autoimmunity

Autoimmune thyroid diseases (AITDs), predominately Graves׳ disease and Hashimoto׳s thyroiditis, comprise the most common autoimmune diseases in humans. Both have the production of anti-thyroid antibody as an important aspect and both are much more prevalent in females, being at least 10 times more common than in males. Using these two clues, a hypothesis for the initiation of thyroid autoimmunity is proposed that helps to make the case that the thyroid is one of the most sensitive sites for autoimmunity and helps account for the prevalence and the observed sex differences in AITDs and associated diseases, such as type 1 diabetes and Latent Autoimmune Diabetes in Adults (LADA). The primary mechanisms proposed involve the underlying state of inflammation as a result of the adipokines, especially leptin, TNF-α, and IL-6, and the receptors able to recognize pathogen-associated molecular patterns (PAMP׳s) and damage-associated molecular patterns (DAMP׳s) through Toll-like receptors (TLR) and others receptors present on thyrocytes. The adipokines are produced by adipose tissue, but have hormone-like and immune modulating properties. As the levels of leptin are significantly higher in females, an explanation for the sex difference in thyroid autoimmunity emerges. The ability of the thyrocytes to participate in innate immunity through the TLR provides an adjuvant-like signal and allows for the action of other agents, such as environmental factors, viruses, bacteria, and even stress to provide the initiation step to break tolerance to thyroid self-antigens. Seeing the thyroid as one of the most sensitive sites for autoimmunity, means that for many autoimmune disorders, if autoimmunity is present, it is likely to also be present in the thyroid - and that that condition in the thyroid was probably earlier. The evidence is seen in multiple autoimmune syndrome.

Diabetes and Hepatitis C: A Two-Way Association

Diabetes and hepatitis C infection are both prevalent diseases worldwide, and are associated with increased morbidity and mortality. Most studies, but not all, have shown that patients with chronic hepatitis C are more prone to develop type 2 diabetes (T2D) compared to healthy controls, as well as when compared to patients with other liver diseases, including hepatitis B. Furthermore, epidemiological studies have revealed that patients with T2D may also be at higher risk for worse outcomes of their hepatitis C infection, including reduced rate of sustained virological response, progression to fibrosis and cirrhosis, and higher risk for development of hepatocellular carcinoma. Moreover, hepatitis C infection and mainly its treatment, interferon α, can trigger the development of type 1 diabetes. In this review, we discuss the existing data on this two-way association between diabetes and hepatitis C infection with emphasis on possible mechanisms. It remains to be determined whether the new curative therapies for chronic hepatitis C will improve outcomes in diabetic hepatitis C patients, and conversely whether treatment with Metformin will reduce complications from hepatitis C virus infection. We propose an algorithm for diabetes screening and follow-up in hepatitis C patients.

Possible factors affecting thyroid dysfunction in hepatitis C virus-infected untreated patients

The present study investigated the association of thyroid dysfunction (TD) with the distribution of chronic hepatitis C virus (HCV) infection in untreated patients. A total of 1,012 cases of HCV-infected patients were collected from different regions, of which 209 patients demonstrated a type of TD (chronic thyroiditis complicated with hyperthyroidism, chronic thyroiditis complicated with hypothyroidism, subclinical hyperthyroidism, subclinical hypothyroidism, hyperthyroidism, hypothyroidism or chronic thyroiditis). The results showed the existence of geographical differences in the types of TD present with HCV infection. The female patients had a higher incidence of autoimmune-related TD than the male patients. High levels of HCV RNA expression were most common in all HCV-infected patients, regardless of the presence of TD. High and medium expression levels of HCV RNA were more prevalent in the patients with autoimmune-related TD. Relative analysis of the HCV RNA levels showed that the pathogenesis of TD was not correlated with the HCV RNA expression levels; however, it may have been associated with autoimmunity. The HCV-infected patients with TD were most commonly middle-aged, whereas young adults were the largest group of patients with HCV and normal thyroid function. Among all HCV genotypes, type 1b was the most common HCV genotype and type 2 was the second most common. Types 3 and 6 were scarce in this study population. No associations were identified between HCV genotypes and thyroid disease. The data of liver function showed that HCV-infected patients with TD had a higher liver dysfunction rate compared with that of the patients with normal thyroid function. Therefore, liver dysfunction may be associated with thyroid disease. This study supports the potential of individualized treatment for HCV-infected patients.

Biological Impact of the TSHβ Splice Variant in Health and Disease

Thyroid stimulating hormone (TSH), a glycoprotein hormone composed of α and β chains, is produced by thyrotrope cells of the anterior pituitary. Within the conventional endocrine loop, pituitary-derived TSH binds to receptors in the thyroid, resulting in the release of the thyroid hormones thyroxine (T₄) and triiodothyronine (T₃). T₄ and T₃ in turn regulate nearly every aspect of mammalian physiology, including basal metabolism, growth and development, and mood and cognition. Although TSHβ has been known for years to be produced by cells of the immune system, the significance of that has remained largely unclear. Recently, a splice variant of TSHβ (TSHβv), which consists of a truncated but biologically functional portion of the native form of TSHβ, was shown to be produced by bone marrow cells and peripheral blood leukocytes, particularly cells of the myeloid/monocyte lineage. In contrast, full-length native TSHβ is minimally produced by cells of the immune system. The present article will describe the discovery of the TSHβv and will discuss its potential role in immunity and autoimmunity, inflammation, and bone remodeling.

Autoimmune and neoplastic thyroid diseases associated with hepatitis C chronic infection

Frequently, patients with hepatitis C virus (HCV) chronic infection have high levels of serum anti-thyroperoxidase and/or anti-thyroglobulin autoantibodies, ultrasonographic signs of chronic autoimmune thyroiditis, and subclinical hypothyroidism, in female gender versus healthy controls, or hepatitis B virus infected patients. In patients with "HCV-associated mixed cryoglobulinemia" (MC + HCV), a higher prevalence of thyroid autoimmune disorders was shown not only compared to controls, but also versus HCV patients without cryoglobulinemia. Patients with MC + HCV or HCV chronic infection show a higher prevalence of papillary thyroid cancer than controls, in particular in patients with autoimmune thyroiditis. Patients with HCV chronic infection, or with MC + HCV, in presence of autoimmune thyroiditis, show higher serum levels of T-helper (Th)1 (C-X-C motif) ligand 10 (CXCL10) chemokine, but normal levels of Th2 (C-C motif) ligand 2 chemokine, than patients without thyroiditis. HCV thyroid infection could act by upregulating CXCL10 gene expression and secretion in thyrocytes recruiting Th1 lymphocytes that secrete interferon-γ and tumor necrosis factor-α. These cytokines might induce a further CXCL10 secretion by thyrocytes, thus perpetuating the immune cascade, which may lead to the appearance of autoimmune thyroid disorders in genetically predisposed subjects. A careful monitoring of thyroid function, particularly where nodules occur, is recommended in HCV patients.

Thyroid involvement in hepatitis C - associated mixed cryoglobulinemia

OBJECTIVE

The prevalence and clinical features of thyroid involvement in patients with hepatitis C virus-associated mixed cryoglobulinemia (MC+HCV) have been reviewed.

DESIGN

A PubMed Medline search was conducted through December 2011 to identify all studies that reported thyroid involvement in MC+HCV patients. Reference lists of the papers initially detected were manually searched to identify additional relevant reports. Studies had to contain sufficient and clear information to be included.

RESULTS

In MC+HCV patients, the following thyroid autoimmune abnormalities were significantly more frequent than in controls: high levels of serum anti-thyroperoxidase autoantibody (AbTPO); high levels of serum AbTPO and/or anti-thyroglobulin autoantibody; humoral and ultrasonographical signs of thyroid autoimmunity (35% vs 16%); prevalence of subclinical hypothyroidism (11% vs 2%). Also, the prevalence of papillary thyroid cancer has been found higher in MC+HCV patients than in controls, in particular in patients with autoimmune thyroiditis. The involvement of T helper 1 immunity and chemokine (C-X-C motif) ligand 10 (CXCL10) may be the pathogenetic basis of the association between MC+HCV and thyroid autoimmunity.

CONCLUSION

These results show a high prevalence of thyroid disorders in patients with MC+HCV and point to the need for careful monitoring of thyroid function in these patients.

Thyroid dysfunction as an unintended side effect of anticancer drugs

BACKGROUND

Several of the currently used anticancer drugs may variably affect thyroid function, with impairment ranging from modified total but not free concentration of thyroid hormones to overt thyroid disease.

SUMMARY

Cytotoxic agents seem to alter thyroid function in a relatively small proportion of adult patients. Anticancer hormone drugs may mainly alter serum levels of thyroid hormone-binding proteins without clinically relevant thyroid dysfunction. Old immunomodulating drugs, such as interferon-α and interleukin-2, are known to induce variably high incidence of autoimmune thyroid dysfunction. Newer immune checkpoint inhibitors, such as anti-CTLA4 monoclonal antibodies, are responsible for a relatively low incidence of thyroiditis and may induce secondary hypothyroidism resulting from hypophysitis. Central hypothyroidism is a well-recognized side effect of bexarotene. Despite their inherent selectivity, tyrosine kinase inhibitors may cause high rates of thyroid dysfunction. Notably, thyroid toxicity seems to be restricted to tyrosine kinase inhibitors targeting key kinase-receptors in angiogenic pathways, but not other kinase-receptors (e.g., epidermal growth factor receptors family or c-KIT). In addition, a number of these agents may also increase the levothyroxine requirement in thyroidectomized patients.

CONCLUSIONS

The pathophysiology of thyroid toxicity induced by many anticancer agents is not fully clarified and for others it remains speculative. Thyroid dysfunction induced by anticancer agents is generally manageable and dose reduction or discontinuation of these agents is not required. The prognostic relevance of thyroid autoimmunity, overt and subclinical hypothyroidism induced by anticancer drugs, the value of thyroid hormone replacement in individuals with abnormal thyrotropin following anticancer systemic therapy, and the correct timing of replacement therapy in cancer patients need to be defined more accurately in well-powered prospective clinical trials.