Interferon alpha treatment and thyroid dysfunction

Thyroid dysfunction in children with Down syndrome: a literature review

INTRODUCTION

This article is an evidence-based review of thyroid disease in children with Down syndrome, including a comparison between various professional guidelines for the management of thyroid disease in children with Down syndrome. Aspects of thyroid disease which are discussed include: congenital hypothyroidism; autoimmune thyroid disease; subclinical hypothyroidism; and hyperthyroidism. The national professional guidelines of Ireland, the United Kingdom, the United States of America, Australia and Canada are reviewed and compared.

MATERIALS AND METHODS

A literature search was conducted using Medline and PubMed. Search terms included 'Down syndrome' and 'thyroid disease', 'hypothyroidism', 'hyperthyroidism', 'subclinical hypothyroidism'.

RESULTS

Eighty-nine articles were retrieved and reviewed for inclusion. The guidelines on the medical management of children with Down syndrome of five expert groups have also been retrieved and reviewed for this discussion. These various guidelines offer largely similar advice regarding frequency of thyroid function tests, with only Ireland and the UK testing less frequently than annually. Only the United Kingdom and Irish Down Syndrome Medical Interest Group guidelines suggest testing for thyroid antibodies at every thyroid screen. None of the guidelines offer suggestions on the optimal course of action to pursue after the discovery of subclinical hypothyroidism.

CONCLUSION

In conclusion, more evidence is required regarding the optimal course of treatment for subclinical hypothyroidism. Such evidence may be best obtained by conducting a prospective randomized control trial.

Hepatitis C virus infection of a thyroid cell line: implications for pathogenesis of hepatitis C virus and thyroiditis

BACKGROUND

Autoimmune and non-autoimmune thyroiditis frequently occur in persons with hepatitis C virus (HCV) infection. Treatment with interferon alpha (IFNα) is also associated with significant risk for the development of thyroiditis. To explore HCV-thyroid interactions at a cellular level, we evaluated whether a human thyroid cell line (ML1) could be infected productively with HCV in vitro.

METHODS AND RESULTS

ML1 cells showed robust surface expression of the major HCV receptor CD81. Using a highly sensitive, strand-specific reverse transcription polymerase chain reaction assay, positive-sense and negative-sense HCV RNA were detected in ML1 cell lysates at days 3, 7, and 14 postinfection with HCV. HCV core protein was expressed at high levels in ML1 supernatants at days 1, 3, 5, 7, and 14 postinfection. The nonstructural protein NS5A was also detected in ML1 cell lysates by Western blotting. HCV entry into ML1 cells was shown to be dependent on the HCV entry factors CD81 and SR-B1/CLA1, while IFNα inhibited HCV replication in ML1 cells in a dose-dependent manner. Supernatants from HCV-infected ML1 cells were able to infect fresh ML1 cells productively, suggesting that infectious virions could be transferred from infected to naïve thyroid cells in vivo. Additionally, HCV infection of ML1 cells led to increased expression of the pro-inflammatory cytokine IL-8.

CONCLUSIONS

For the first time, we have demonstrated that HCV can infect human thyroid cells in vitro. These findings strongly suggest that HCV infection of thyrocytes may play a role in the association between chronic HCV infection and thyroid autoimmunity. Furthermore, the thyroid may serve as an extrahepatic reservoir for HCV viral replication, thus contributing to the persistence of viral infection and to the development of thyroid autoimmunity.

Genetic analysis of interferon induced thyroiditis (IIT): evidence for a key role for MHC and apoptosis related genes and pathways

Autoimmune thyroid diseases (AITD) have become increasingly recognized as a complication of interferon-alpha (IFNα) therapy in patients with chronic Hepatitis C virus (HCV) infection. Interferon-induced thyroiditis (IIT) can manifest as clinical thyroiditis in approximately 15% of HCV patients receiving IFNα and subclinical thyroiditis in up to 40% of patients, possibly resulting in either dose reduction or discontinuation of IFNα treatment. However, the exact mechanisms that lead to the development of IIT are unknown and may include IFNα-mediated immune-recruitment as well as direct toxic effects on thyroid follicular cells. We hypothesized that IIT develops in genetically predisposed individuals whose threshold for developing thyroiditis is lowered by IFNα. Therefore, our aim was to identify the susceptibility genes for IIT. We used a genomic convergence approach combining genetic association data with transcriptome analysis of genes upregulated by IFNα. Integrating results of genetic association, transcriptome data, pathway, and haplotype analyses enabled the identification of 3 putative loci, SP100/110/140 (2q37.1), HLA (6p21.3), and TAP1 (6p21.3) that may be involved in the pathogenesis of IIT. Immune-regulation and apoptosis emerged as the predominant mechanisms underlying the etiology of IIT.

Frequency of thyroid dysfunctions during interferon alpha treatment of single and combination therapy in hepatitis C virus-infected patients: a systematic review based analysis

BACKGROUND

Thyroid dysfunction is the commonest endocrinopathy associated with HCV infection due to interferon-based treatment. This comprehensive and systematic review presents the available evidence for newly developed thyroid antibodies and dysfunctions during interferon treatment (both single and combination) in HCV patients.

METHODOLOGY/PRINCIPAL FINDINGS

This systematic review was conducted in accordance with the PRISMA guidelines. The data generated were used to analyze the risk for thyroid dysfunctions during interferon (IFN) treatment in HCV patients. There was a wide range in the incidence of newly developed thyroid dysfunctions and thyroid antibodies in HCV patients during IFN treatment (both single and combination). The wide range of incidence also denoted the possibility of factors other than IFN treatment for thyroid-related abnormalities in HCV patients. These other factors include HCV viral factors, genetic predisposition, environmental factors, and patho-physiological factors. Variations in IFN dosage, treatment duration of IFN, definition/criteria followed in each study for thyroid dysfunction and irregular thyroid function testing during treatment in different studies influence the outcome of the single studies and jeopardise the validity of a pooled risk estimate of side effects of thyroid dysfunction. Importantly, reports differ as to whether the thyroid-related side effects disappear totally after withdrawal of the IFN treatment.

CONCLUSIONS/SIGNIFICANCE

The present review shows that there is a wide range in the incidence of newly developed thyroid dysfunctions and thyroid antibodies in IFN treated HCV patients. This is a comprehensive attempt to collate relevant data from 56 publications across several nations about IFN (both mono and combination therapy) related thyroid dysfunction among HCV patients. The role of each factor in causing thyroid dysfunctions in HCV patients treated with IFN should be analyzed in detail in future studies, for a better understanding of the problem and sounder clinical management of the disease.

Autoimmune thyroid disorders in hepatitis C virus infection: Effect of interferon therapy

The hepatitis C virus infection represents an important public health problem and is associated with various hepatic and extrahepatic manifestations. Symptoms outside of the liver can occur in multiple organ systems, including hematologic, renal, dermatologic, endocrine, and rheumatologic systems. Among these different organ systems, special attention has focused on the endocrine system because it affects almost every organ in the body. Among the endocrine disorders, thyroid problems are the most common and the thyroid is one of the principal target organs for extrahepatic manifestations in HCV infected patients. In addition, research data suggest that interferon treatment may be associated with immune-mediated thyroid lesions. However, case reports suggest that the response of thyroid extrahepatic manifestations to interferon in patients with chronic HCV is greatly different. The objective of this study was to summarize currently available data on thyroid conditions associated with chronic HCV infection. Moreover, we investigate the incidence of the development of immune mediated thyroid disorders during interferon therapy in these patients.

Thyroid dysfunction in chinese patients with chronic hepatitis C treated with interferon alpha: incidence, long-term outcome and predictive factors

BACKGROUND

Thyroid dysfunction (TD) represents an extra-hepatic manifestation of chronic hepatitis C (CHC) and it may also be a side effect of interferon-alpha (IFN-α) based treatment. However, previous studies have shown a wide variation in the incidence of TD in patients with CHC. Furthermore, the long-term outcomes and the predictive factors of TD in patients who receive IFN-α based treatment have still not been fully studied.

OBJECTIVES

The purpose of this study was to describe the incidence and long-term outcomes of TD in Chinese patients with CHC receiving IFN-αbased treatment. We also aimed to identify the predictive factors of TD associated with this type of therapy.

PATIENTS AND METHODS

A retrospective case-series study of 592 consecutive CHC patients with normal baseline thyroid functions, who received IFN-αbased therapy, was performed. Thyroid function was assessed at baseline and every three months during treatment, as well as in the follow-up after cessation of therapy. The incidence and long-term outcomes of TD were observed. The prevalence of pretreatment thyroid peroxidase antibodies (TPOAb) were assayed in a sex- and age-matched nested case-control study. Multivariable stepwise regression analysis was used to explore the independent effects of the baseline factors, on the incidence of TD.

RESULTS

At the end of the IFN-αbased therapy, 68 patients (11.5%) in the study had developed TD, 58 patients (85.3%) presented with subclinical TD, and only 10 patients (14.7%) developed overt thyroiditis. The thyroid function of 46 patients (67.8%) spontaneously returned to normal in the six months of follow-up and only three patients (4.4%) had persistent overt TD symptoms after the 24 month follow-up period. Multivariate stepwise analysis suggested that gender and pretreatment TPOAb were the independent factors related to the incidence of TD. Both female patients (OR, 4.31; 95%CI, 2.06-7.31; P = 1.26×10-4) and participants with a positive pretreatment TPOAb (OR = 3.9, 95%CI, 1.72-8.54, P = 0.008) had an increased risk for the development of TD.

CONCLUSIONS

The incidence of TD in Chinese patients with CHC during IFN-αbased therapy was 11.5%, the majority of which was subclinical, while only a very small group had long-term overt TD requiring ongoing medical therapy. Female gender and pretreatment TPOAb positivity are risk factors for the development of TD during IFN-αbased therapy.

Association of interferon-alpha and ribavirin-induced thyroid dysfunction with severity of disease and response to treatment in pakistani asian patients of chronic hepatitis C

Objective. To determine the association of thyroid dysfunction with the severity of the disease and response to treatment in patients of chronic hepatitis C. Design. Cohort study. Patients. One hundred and sixty seven noncirrhotic chronic hepatitis C patients were grouped into treatment group (n = 107) and control group (n = 60). Measurements. Baseline S. ALT and S. AST by IFCC and S. TSH, S. free T4, and S.T3 level were measured by chemiluminescence method. The severity of the disease was measured by Knodell histopathological index (HPI) on liver biopsy. Study group patients underwent 24-weeks IFN and ribavirin therapy and thyroid functions were determined at weeks 0, 12, and 24. Response to therapy was determined by PCR-HCV test. Results. 20 treated patients (18.69%) developed thyroid dysfunction with relative risk (RR) of 11.25 and attributable risk (AR) of 91%. Females were at higher risk. Hypothyroidism was common than hyperthyroidism. There was no significant association between thyroid dysfunction and severity of the disease (P = 0.81) and response to therapy (P = 0.79). Conclusion. Interferon-alpha and ribavirin therapy induces thyroid dysfunction in chronic hepatitis C patients. There is no association between severity of disease and response to therapy with interferon-induced thyroid dysfunction.

Autoimmune thyroid disease

PURPOSE OF REVIEW

Autoimmune thyroid disorders (AITDs) are the most common organ-specific autoimmune disorders. The genetics as well as clinical and laboratory manifestations of AITDs are reviewed.

RECENT FINDINGS

We discuss the association between specific rheumatologic disorders and AITDs and manifestations of AITDs that mimic rheumatologic disorders. The recently discovered common molecular pathways involved in these processes are discussed.

SUMMARY

AITDs and rheumatologic disorders have significant commonalities both clinically and etiologically. This information is important for rheumatologists and primary care physicians who care for patients with these disorders.

B-cell-activating factor affects the occurrence of thyroid autoimmunity in chronic hepatitis C patients treated with interferon alpha

Chronic hepatitis C (CHC) patients frequently suffer from thyroid disorders during interferon therapy. However, the mechanism remains unclear. In this study, we investigated the association between serum B-cell-activating factor belonging to the TNF family (BAFF) levels and the presence of antithyroid peroxidase antibody (anti-TPO) in CHC patients treated with pegylated interferon alpha and ribavirin combination therapy. Six months after the therapy, anti-TPO antibody was detected in 10 (males, 1; females, 9) of 50 patients. The mean age of these patients was higher than that of the anti-TPO-negative patients (61 yr versus 55 yr). Before treatment, the serum BAFF levels of the anti-TPO-positive patients were higher than those of the anti-TPO-negative patients. After starting therapy, the serum BAFF levels of both the anti-TPO-positive and -negative patient groups were elevated. Our findings suggest that the serum BAFF concentration before therapy can predict the risk of thyroid autoimmunity in elderly female patients with CHC.

Interferon-alpha-induced destructive thyroiditis followed by Graves' disease in a patient with chronic hepatitis C: a case report

Interferon-induced thyroiditis (IIT) is a major clinical problem for patients receiving interferon-alpha (IFN-α) therapy. But, destructive thyroiditis followed by Graves' disease associated with IFN-α therapy is very rarely reported. Herein, we report a rare case of pegylated IFN-α (pegIFN-α) induced destructive thyroiditis followed by Graves' disease in a patient with HCV infection. A 31-yr-old woman suffered from chronic active hepatitis C and was treated with pegIFN-α and ribavirin for 12 months. Results of a thyroid function test and autoantibody levels were normal before IFN-α therapy was initiated. Destructive thyrotoxicosis appeared seven months after the initiation of IFN-α therapy, followed by Graves' thyrotoxicosis two months after the cessation of therapy. The diagnoses of destructive thyroiditis and Graves' disease were confirmed by the presence of TSH receptor antibodies in addition to Tc-99m scintigraphy findings. The patient's antithyroglobulin antibody titer increased gradually during IFN-α therapy and remained weakly positive after IFN-α therapy was discontinued.

Side-effects of pegylated interferon plus ribavirin therapy with or without protease inhibitor direct acting antiviral agents during treatment of chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection affects 2–3% of the population, approximately 170 million people worldwide, causing chronic HCV-related hepatitis with subsequent liver cirrhosis, hepatic failure, hepatocellular cancer, and liver-related mortality in a large number of patients. The gold standard therapy, pegylated interferon alpha in combination with ribavirin can eradicate hepatitis C virus infection in approx. 40% of treatment-naïve patients infected with HCV genotype G1, and only 15–20% of patients with previous treatment. Success rate is substantially improved with the development and registration of two direct acting anti-hepatitis C virus protease inhibitors (boceprevir and telaprevir) in the second decade of 21st century: combined with the standard therapy, almost three quarter of previously untreated, and more than half of previously unsuccessfully treated patients can achieve sustained viral response with protease inhibitor based triple therapies. A major barrier to successful treatment is the association of peginterferon/ribavirin therapy with frequent and sometimes serious adverse effects. In clinical trials, approximately 10–15% of treated patients discontinue peginterferon and ribavirin due to adverse events; however, in routine clinical practice, the rate of treatment discontinuation has been reported to be substantially higher. The side effects of peginterferon/ribavirin therapy affect virtually all organ systems, and addition of protease inhibitor can amplify these side effects (particularly anemia), and/or may lead to new ones (i.e., dysgeusia with boceprevir or skin rush with telaprevir). There is considerable regional and global variability in the nature and prevalence of these adverse effects as well as in the best strategies to ameliorate their impact on hepatitis C virus treatment. This article summarizes the side effects of dual and triple therapies and their management based on the labels of the drugs, on a comprehensive literature review, as well as on the recently published opinion of an international panel of experts – with the provision of providing help for the physicians treating hepatitis C virus infection to achieve the best possible success with the highest possible safety for the patients. Orv. Hetil., 2011, 152, 1997–2009.

Thyroid dysfunction from antineoplastic agents

Unlike cytotoxic agents that indiscriminately affect rapidly dividing cells, newer antineoplastic agents such as targeted therapies and immunotherapies are associated with thyroid dysfunction. These include tyrosine kinase inhibitors, bexarotene, radioiodine-based cancer therapies, denileukin diftitox, alemtuzumab, interferon-α, interleukin-2, ipilimumab, tremelimumab, thalidomide, and lenalidomide. Primary hypothyroidism is the most common side effect, although thyrotoxicosis and effects on thyroid-stimulating hormone secretion and thyroid hormone metabolism have also been described. Most agents cause thyroid dysfunction in 20%-50% of patients, although some have even higher rates. Despite this, physicians may overlook drug-induced thyroid dysfunction because of the complexity of the clinical picture in the cancer patient. Symptoms of hypothyroidism, such as fatigue, weakness, depression, memory loss, cold intolerance, and cardiovascular effects, may be incorrectly attributed to the primary disease or to the antineoplastic agent. Underdiagnosis of thyroid dysfunction can have important consequences for cancer patient management. At a minimum, the symptoms will adversely affect the patient's quality of life. Alternatively, such symptoms can lead to dose reductions of potentially life-saving therapies. Hypothyroidism can also alter the kinetics and clearance of medications, which may lead to undesirable side effects. Thyrotoxicosis can be mistaken for sepsis or a nonendocrinologic drug side effect. In some patients, thyroid disease may indicate a higher likelihood of tumor response to the agent. Both hypothyroidism and thyrotoxicosis are easily diagnosed with inexpensive and specific tests. In many patients, particularly those with hypothyroidism, the treatment is straightforward. We therefore recommend routine testing for thyroid abnormalities in patients receiving these antineoplastic agents.

Novel variant of thyroglobulin promoter triggers thyroid autoimmunity through an epigenetic interferon alpha-modulated mechanism

Autoimmune thyroid diseases (AITD) arise from complex interactions between genetic, epigenetic, and environmental factors. Whole genome linkage scans and association studies have established thyroglobulin (TG) as a major AITD susceptibility gene. However, the causative TG variants and the pathogenic mechanisms are unknown. Here, we describe a genetic/epigenetic mechanism by which a newly identified TG promoter single-nucleotide polymorphism (SNP) variant predisposes to AITD. Sequencing analyses followed by case control and family-based association studies identified an SNP (-1623A→G) that was associated with AITD in the Caucasian population (p = 0.006). We show that the nucleotide substitution introduced by SNP (-1623A/G) modified a binding site for interferon regulatory factor-1 (IRF-1), a major interferon-induced transcription factor. Using chromatin immunoprecipitation, we demonstrated that IRF-1 binds to the 5' TG promoter motif, and the transcription factor binding correlates with active chromatin structure and is marked by enrichment of mono-methylated Lys-4 residue of histone H3, a signature of active transcriptional enhancers. Using reporter mutations and siRNA approaches, we demonstrate that the disease-associated allele (G) conferred increased TG promoter activity through IRF-1 binding. Finally, treatment of thyroid cells with interferon α, a known trigger of AITD, increased TG promoter activity only when it interacted with the disease-associated variant through IRF-1 binding. These results reveal a new mechanism of interaction between environmental (IFNα) and genetic (TG) factors to trigger AITD.

Management of adverse effects of Peg-IFN and ribavirin therapy for hepatitis C

HCV infects approximately 2-3% of the global population and is a leading cause of end-stage liver disease and hepatocellular carcinoma. Treatment of HCV infection with Peg-IFN in combination with ribavirin can eradicate HCV infection in 40-90% of patients; however, a major barrier to treatment uptake and delivery is the association of this therapy with frequent and, at times, serious adverse effects. Recognition and effective management of these adverse effects are critical components of the successful treatment of chronic HCV infection. In clinical trials, approximately 10-15% of patients discontinue Peg-IFN and ribavirin therapy due to adverse effects; however, in clinical practice, the rate of treatment discontinuation has been reported to be substantially higher. The off-target effect of Peg-IFN and ribavirin impacts most, if not all, organ systems; the most common adverse effects are hematologic, dermatologic, neurologic, immunologic, gastrointestinal, pulmonary, cardiovascular, and ocular. Regional and global variability exists in the nature of these adverse effects and the strategies employed to ameliorate their impact. This article provides a comprehensive literature review that systematically describes the adverse effects of Peg-IFN-α and ribavirin on various organ systems and, more importantly, recommends consensus approaches to managing those effects.

IFN-α mediates the development of autoimmunity both by direct tissue toxicity and through immune cell recruitment mechanisms

IFN-α is known to play a key role in autoimmunity, but the mechanisms are uncertain. Although the induction of autoimmunity by IFN-α is consistent with primarily immunomodulatory effects, the high frequency of nonautoimmune inflammation suggests other mechanisms. We used thyroiditis as a model to dissect these possibilities. IFN-α treatment of cultured thyrocytes increased expression of thyroid differentiation markers, thyroglobulin, thyroid-stimulating hormone receptor, thyroid peroxidase, and sodium iodide transporter. RNAseq analysis demonstrated that pathways of Ag presentation, pattern recognition receptors, and cytokines/chemokines were also stimulated. These changes were associated with markedly increased nonapoptotic thyroid cell death, suggesting direct toxicity. To corroborate these in vitro findings, we created transgenic mice with thyroid-specific overexpression of IFN-α under control of the thyroglobulin promoter. Transgenic mice developed marked inflammatory thyroid destruction associated with immune cell infiltration of thyroid and surrounding tissues leading to profound hypothyroidism, findings consistent with our in vitro results. In addition, transgenic mice thyroids showed upregulation of pathways similar to those observed in cultured thyrocytes. In particular, expression of granzyme B, CXCL10, a subset of the tripartite motif-containing family, and other genes involved in recruitment of bystander cytotoxic immune responses were increased. Pathways associated with apoptosis and autophagy were not induced. Taken together, our data demonstrate that the induction of tissue inflammation and autoimmunity by IFN-α involves direct tissue toxic effects as well as provocation of destructive bystander immune responses.

The natural history of interferon-α induced thyroiditis in chronic hepatitis c patients: a long term study

BACKGROUND

Autoimmune thyroid disease is a common complication of patients with chronic hepatitis C undergoing combination pegylated interferon-α and ribavirin treatment. A small proportion develops interferon-induced thyroiditis of which the long term natural history is unknown and how it compares with de novo thyroiditis. The aim of the study is to determine the natural history of thyroid disease including antibody profile in this particular setting 36 months from the completion of therapy.

METHODS

A cohort of 18 hepatitis C patients (mean age 45 ± 8 years (standard deviation)) who developed exclusively thyroiditis in this setting was followed every 12 months after the completion of therapy for 36 months. Investigations included thyrotropin, free tetra-iodothyronine, free tri-iodothyronine levels and thyroid autoantibodies.

RESULTS

None of the patients developed any long term thyroid disease. Two patients had a prolonged hypothyroid phase of the thyroiditis early after the completion of treatment but recovered fully. The remaining 16 patients remained euthyroid. Similarly, thyroid autoantibodies all declined and returned to reference range.

CONCLUSIONS

The long term natural history in this small series of interferon induced thyroiditis was benign. If a larger series confirms a similar outcome then there is no long term residual effect on thyroid function and follow-up testing would not be warranted.

Environmental triggers of thyroiditis: hepatitis C and interferon-α

Autoimmune thyroid diseases (AITD) are postulated to develop as a result of a complex interplay between several genetic and environmental influences. The pathogenesis of AITD is still not clearly defined. However, among the implicated triggers (e.g. iodine, infections, medications), more recent data confirmed strong associations of AITD with the hepatitis C virus (HCV) infection and interferon-α (IFNα) therapy. Moreover, it is likely that HCV and IFN act in synergism to trigger AITD in patients. Indeed, approximately 40% of HCV patients develop either clinical or subclinical disease while receiving IFNα. Interferon induced thyroiditis (IIT) can manifest as non-autoimmune thyroiditis (presenting as destructive thyroiditis, or non-autoimmune hypothyroidism), or autoimmune thyroiditis [presenting with clinical features of Graves' disease (GD) or Hashimoto's thyroiditis (HT)]. Although not yet clearly understood, it is thought that IFNα can induce thyroiditis via both immune stimulatory and direct toxic effects on the thyroid. In view of the high frequency of IIT, routine screening and surveillance of HCV patients receiving IFNα is recommended to avoid the complications, such as cardiac arrhythmias, associated with thyrotoxicosis. In summary, IIT is a common clinical problem that can be readily diagnosed with routine thyroid function screening of HCV patients receiving IFN. The treatment of IIT consists of the standard therapy for differing clinical manifestations of IIT such as GD, HT, or destructive thyroiditis. However, anti-thyroid medications are not recommended in this setting since they can potentially be hepatotoxic.

Thyroid hormonal disturbances related to treatment of hepatitis C with interferon-alpha and ribavirin

OBJECTIVE

To characterize thyroid disturbances induced by interferon-alpha and ribavirin therapy in patients with chronic hepatitis C.

INTRODUCTION

Interferon-alpha is used to treat chronic hepatitis C infections. This compound commonly induces both autoimmune and non-autoimmune thyroiditis.

METHODS

We prospectively selected 26 patients with chronic hepatitis C infections. Clinical examinations, hormonal evaluations, and color-flow Doppler ultrasonography of the thyroid were performed before and during antiviral therapy.

RESULTS

Of the patients in our study, 54% had no thyroid disorders associated with the interferon-alpha therapy but showed reduced levels of total T3 along with a decrease in serum alanine aminotransferase. Total T4 levels were also reduced at 3 and 12 months, but free T4 and thyroid stimulating hormone (TSH) levels remained stable. A total of 19% of the subjects had autoimmune interferon-induced thyroiditis, which is characterized by an emerge of antithyroid antibodies or overt hypothyroidism. Additionally, 16% had non-autoimmune thyroiditis, which presents as destructive thyroiditis or subclinical hypothyroidism, and 11% remained in a state of euthyroidism despite the prior existence of antithyroidal antibodies. Thyrotoxicosis with destructive thyroiditis was diagnosed within three months of therapy, and ultrasonography of these patients revealed thyroid shrinkage and discordant change in the vascular patterns.

DISCUSSION

Decreases in the total T3 and total T4 levels may be related to improvements in the hepatocellular lesions or inflammatory changes similar to those associated with nonthyroidal illnesses. The immune mechanisms and direct effects of interferon-alpha can be associated with thyroiditis.

CONCLUSION

Interferon-alpha and ribavirin induce autoimmune and non-autoimmune thyroiditis and hormonal changes (such as decreased total T3 and total T4 levels), which occur despite stable free T4 and TSH levels. A thyroid hormonal evaluation, including the analysis of the free T4, TSH, and antithyroid antibody levels, should be mandatory before therapy, and an early re-evaluation within three months of treatment is necessary as an appropriate follow-up.

Cases of interferon-alpha and interferon-beta-induced thyroiditis

Interferons are currently the major treatment modality for several malignant and non-malignant diseases such as chronic hepatitis C and B, multiple sclerosis, hematological malignancies, malignant melanoma, renal cell carcinoma, etc. Thyroid disorders develop in some of the interferon-treated patients with the incidence ranging from 1% to 35%. These complications may often result in dose reduction or discontinuation of interferon therapy. Interferon induced thyroid disorders can be classified as autoimmune and non-autoimmune thyroiditis. There are many studies on the development of thyroid dysfunction in interferon-alpha treated patients with chronic hepatitis C and in patients with multiple sclerosis treated with interferon-beta. There is a dearth of information about the incidence and characteristics of thyroid abnormalities in patients with hematological malignancies receiving interferon-alpha. A number of genetic determinants are discussed as causes for thyroid impairment (sex, age, ethnic group, genes involved in the thyroid immune regulation), as well as non-genetic factors (related to the underlying disease--hepatitis C virus; multiple sclerosis; therapeutic regimens of interferon administration, iodine concentration in the environment, presence of thyroid autoantibodies at the start of treatment, etc.). In this article we summarize the relevant data about the frequency and characteristics of thyroid disorders in patients treated with interferons, the risk factors and the mechanisms for their development and the peculiarities of the course, detection and treatment of these complications. The review of the literature motivates studying the thyroid function of specific groups of patients receiving interferon in order to clarify the influence of the factors drug and disease on the thyroid gland. Early detection and adequate treatment of thyroid dysfunction in these patients is important to avoid complications that may compromise treatment.

Hepatitis C and interferon induced thyroiditis

Autoimmune thyroid diseases (AITDs) are complex diseases that develop as a result of interactions between genetic, epigenetic, and environmental factors. Significant progress has been made in our understanding of the genetic and environmental triggers contributing to AITD. The major environmental triggers of AITD include iodine, smoking, medications, pregnancy, and possibly stress. In this review we will focus on two well-documented environmental triggers of AITD, hepatitis C virus (HCV) infection and interferon alpha (IFNa) therapy. Chronic HCV infection has been shown to be associated with increased incidence of clinical and subclinical autoimmune thyroiditis (i.e. the presence of thyroid antibodies in euthyroid subjects). Moreover, IFNa therapy of chronic HCV infection is associated with subclinical or clinical thyroiditis in up to 40% of cases which can be autoimmune, or non-autoimmune thyroiditis. In some cases interferon induced thyroiditis (IIT) in chronic HCV patients may result in severe symptomatology necessitating discontinuation of therapy. While the epidemiology and clinical presentation of HCV and interferon induced thyroiditis have been well characterized, the mechanisms causing these conditions are still poorly understood.

Anti-inflammatory treatment of uveitis with biologicals: new treatment options that reflect pathogenetic knowledge of the disease

BACKGROUND

Endogenous uveitis is a sight-threatening disease. In addition to corticosteroids, immunosuppressive agents are commonly used to treat patients with severe course. Immunosuppressive drugs act nonspecifically, rather than providing a specific interaction with the critical pathogenetic pathways of uveitis. Better knowledge of the basic mechanisms underlying uveitis and of the molecules that are important for regulating inflammation has helped to create new and more specific treatment approaches. Biological therapy for inflammatory diseases employs substances that interfere with specific molecules or pathways induced in the body during the inflammatory process.

METHODS

This review gives an overview on molecules that play a critical role in the pathogenetic process of uveitis, as has been observed in patients or the respective animal models, and summarizes the current experience with biologicals for the treatment of uveitis refractive to conventional immunosuppressives.

Interferon therapy in rheumatic diseases: state-of-the-art 2010

PURPOSE OF REVIEW

Interferons are natural glycoproteins that have antiviral, antiproliferative and immune regulatory functions. They are not only involved in the pathogenesis of certain autoimmune conditions but are also useful in the treatment of some rheumatologic disorders, notably Behçet's syndrome.

RECENT FINDINGS

Interferon alpha (IFNalpha) has been recommended for severe eye involvement in Behçet's syndrome, especially when there is a significant drop in visual acuity and/or retinal involvement. It can induce a high rate of complete remission that may also persist after its discontinuation. When given early at the beginning, interferon might be effective in ameliorating the attacks of familial Mediterranean fever resistant to colchicine treatment. The combination of PEGylated IFNalpha with ribavirin and rituximab emerges as a novel and promising treatment providing complete clinical response and viral clearance in hepatitis C virus-associated mixed cryoglobulinemia. Limited data also suggest that interferon may induce remissions in Churg-Strauss patients who fail to respond to conventional immunosuppressive treatment.

SUMMARY

Among several rheumatologic diseases, IFNalpha has found more widespread use in Behçet's syndrome and hepatitis C virus-associated mixed cryoglobulinemia despite a paucity of formal studies. Patients should be carefully monitored for the frequent and dose-dependent adverse effects.

Opportunistic autoimmune disorders: from immunotherapy to immune dysregulation

Rapid advances in our understanding of the immune network have led to treatment modalities for malignancies and autoimmune diseases based on modulation of the immune response. Yet therapeutic modulation has resulted in immune dysregulation and opportunistic autoimmune sequelae, despite prescreening efforts in clinical trials. This review focuses on recent clinical data on opportunistic autoimmune disorders arising from three immunotherapeutic modalities: (1) systemic immunomodulators, including interferon-alpha (also used to treat hepatitis C patients) and interferon-beta; (2) monoclonal antibodies to CTLA-4 and CD52, and (3) hematopoietic stem cell transplantation. Uncategorized predisposing factors in these patients include major histocompatibility complex and gender genetics, prevalence of different autoimmune diseases, prior chemotherapy, underlying disorder (e.g., hepatitis C), and preconditioning regimens as part of organ and stem cell transplants. Not unexpectedly, the prevalent autoimmune thyroid disease surfaced frequently. Our combination models to study the balance between thyroid autoimmunity and tumor immunity upon regulatory T-cell perturbation are briefly described.

Interferon-alpha induced and ribavirin induced thyroid dysfunction in patients with chronic hepatitis C

Chronic hepatitis C (CHC) is one of the commonest infectious diseases of the liver and may lead to cirrhosis or hepatocellular carcinoma. Combination therapy with pegylated interferon (PEG-IFN) and Ribavirin is the treatment of choice for CHC. Combination therapy is thought to act by means of antiviral mechanisms and immunomodulation. Thyroid dysfunction is the most common autoimmune adverse effect associated with combination therapy; hypothyroidism is more common than hyperthyroidism. Antithyroid antibodies and female sex have a predictive value in the development of interferon induced thyroid disease (IITD). Patients with CHC should be informed of the possibility of side effects on the thyroid gland. Screening for antithyroid antibodies and thyroid function tests should be performed in patients with CHC before the commencement of antiviral treatment, and during and after it. This article reviews different aspects of IITD, including its pathogenesis, clinical manifestations, association with treatment regimens and treatment response and the outcome of thyroid dysfunction.

Interferon induced thyroiditis

Interferon-alpha (IFNalpha) is used for the treatment of various disorders, most notable chronic hepatitis C virus (HCV) infection. One of the commonest side effects of IFNalpha therapy is thyroiditis, with up to 40% of HCV patients on IFNalpha developing clinical or subclinical disease. In some cases interferon induced thyroiditis (IIT) may result in severe symptomatology necessitating discontinuation of therapy. IIT can manifest as clinical autoimmune thyroiditis, presenting with symptoms of classical Hashimoto's thyroiditis or Graves' disease, or as non-autoimmune thyroiditis. Non-autoimmune thyroiditis can manifest as destructive thyroiditis, with early thyrotoxicosis and later hypothyroidism, or as non-autoimmune hypothyroidism. While the epidemiology and clinical presentation of IIT have been well characterized the mechanisms causing IIT are still poorly understood. It is likely that the hepatitis C virus (HCV) itself plays a role in the disease, as the association between HCV infection and thyroiditis is well established. It is believed that IFNalpha induces thyroiditis by both immune stimulatory effects and by direct effects on the thyroid. Early detection and therapy of this condition are important in order to avoid complications of thyroid disease such as cardiac arrhythmias.

The swinging thyroid in hepatitis C infection and interferon therapy

Described is a case of triphasic thyroid response in a 53-year-old man while undergoing combination interferon α-2b and ribavirin treatment for chronic hepatitis C infection. He developed the classical biphasic thyroiditis during treatment and was treated expectantly. However, 8 weeks after the completion of therapy, he developed T3-Graves-like thyrotoxicosis, which was confirmed with a diffuse-uptake thyroid scan and positive thyroid stimulating immunoglobulin. He was treated as having Graves' disease arising de novo with thiourea, and he achieved rapid remission. This is thought to be only the second case described, and it offers a unique opportunity to understand the possible pathogenesis of this fascinating condition. This is a relative novel entity and highlights the need for continuing thyroid monitor after treatment. Management also needs to be specific for each particular phase of the condition.

Anti-TNFalpha blockers, autoantibodies and autoimmune diseases

Anti-TNFalpha blockers are extensively used in the management of chronic inflammatory disorders. Their administration may be associated with the generation of autoantibodies; this review focuses on the autoimmune phenomena linked to anti-TNFalpha inhibition, on the hypothesized pathogenetic mechanisms and on the clinical implications. While the development of antinuclear and, less frequently, of anti-DNA antibodies is a common finding, the onset of autoimmune diseases during anti-TNFalpha blocker treatment is a rare event, which needs to be promptly recognized in order to plan the appropriate management. Moreover the specific autoantibodies associated with rheumatoid arthritis are considered before and after biotherapy. Similarities and differences among infliximab, etanercept and adalimumab concerning induced autoimmune phenomena are underlined.

Thyroid dysfunction in patients with chronic hepatitis C: virus- or therapy-related?

BACKGROUND AND AIMS

Thyroid dysfunction (TD) represents an extrahepatic manifestation of chronic hepatitis C (CHC). Moreover, the currently approved treatment of CHC is often associated with TD. However, it remains debatable if TD is mainly virus- or treatment-related. The aim of this study was to assess the incidence and features of TD, and to identify its predictors in treated and untreated CHC patients.

METHODS

Ninety-four patients with CHC and normal thyroid function were evaluated long-term for TD: 33 were untreated (control group) and 61 were treated with pegylated interferon alpha (PEG-IFN-alpha) plus ribavirin (treatment group). Mean follow up was 80.1 and 39.4 months, respectively.

RESULTS

All patients in the control group remained euthyroid, while 13 treated patients (21.3%) developed TD (P < 0.001). Eleven of these were diagnosed with hypothyroidism and two with hyperthyroidism, which then converted to hypothyroidism. In the majority of cases (9/13, 69.2%) TD did not reverse after treatment discontinuation and required hormone replacement therapy. Pretreatment virological parameters did not predict TD, according to multiple logistic regression analysis. TD was not associated with total dose of PEG-IFN-alpha or ribavirin, viral kinetics or with virological outcome, but it was linked to development of other therapy-related autoimmune disorders (odds ratio, 8.29).

CONCLUSION

Antiviral therapy of CHC possibly induces de novo or exacerbates pre-existing silent TD. TD does not seem to correlate with any pretreatment virological parameter; it is probably not related to dose or treatment duration, nor linked to viral kinetics or virological outcome. The role of chronic hepatitis C per se in TD remains to be determined.

Endocrine and liver interaction: the role of endocrine pathways in NASH

This article reviews evidence that causally links hormonal disorders with hepatobiliary disease, and gives particular focus to nonalcoholic steatohepatitis (NASH). The downstream mechanisms by which endocrine disturbances cause liver disease might be similar to those involved in the development of primary liver disease. Hypothyroidism, for example, might lead to NASH, cirrhosis and potentially liver cancer via the development of hyperlipidemia and obesity. Patients with growth hormone deficiency have a metabolic-syndrome-like phenotype that is also associated with the development of NASH. Polycystic ovary syndrome is a common endocrine disorder that is often associated with insulin resistance, the metabolic syndrome, altered levels of liver enzymes and the development of NASH. Recent findings support a role of dehydroepiandrosterone sulfate deficiency in the development of advanced NASH. In addition, adrenal failure is increasingly reported in patients with end stage liver disease and in patients who have received a liver transplant, which suggests a bidirectional relationship between liver and endocrine functions. Clinicians should, therefore, be aware of the potential role of endocrine disorders in patients with cryptogenic liver disease and of the effects of liver function on the endocrine system.

Endocrine and liver interaction: the role of endocrine pathways in NASH

This article reviews evidence that causally links hormonal disorders with hepatobiliary disease, and gives particular focus to nonalcoholic steatohepatitis (NASH). The downstream mechanisms by which endocrine disturbances cause liver disease might be similar to those involved in the development of primary liver disease. Hypothyroidism, for example, might lead to NASH, cirrhosis and potentially liver cancer via the development of hyperlipidemia and obesity. Patients with growth hormone deficiency have a metabolic-syndrome-like phenotype that is also associated with the development of NASH. Polycystic ovary syndrome is a common endocrine disorder that is often associated with insulin resistance, the metabolic syndrome, altered levels of liver enzymes and the development of NASH. Recent findings support a role of dehydroepiandrosterone sulfate deficiency in the development of advanced NASH. In addition, adrenal failure is increasingly reported in patients with end stage liver disease and in patients who have received a liver transplant, which suggests a bidirectional relationship between liver and endocrine functions. Clinicians should, therefore, be aware of the potential role of endocrine disorders in patients with cryptogenic liver disease and of the effects of liver function on the endocrine system.

The natural history of interferon-alpha2b-induced thyroiditis and its exclusivity in a cohort of patients with chronic hepatitis C infection

BACKGROUND

Interferon-alpha2b (IFN-alpha2b) is well known to cause both hyper- and hypo-thyroidism. In the former, the commonest aetiology is thyroiditis. As there is no previous data to fully characterize the entity of IFN-related thyroiditis, the aim of this study is to document in detail its evolution in a cohort of hepatitis C patients treated with pegylated IFN-alpha2b and Ribavirin (RBV).

METHODS

A prospective observational study was conducted in patients who developed thyroid diseases whilst receiving combination of pegylated IFN-alpha2b and RBV for hepatitis C. The patients were followed with monthly thyrotropin (TSH). Where TSH was undetectable, free tetra- (fT4) and tri-iodothyronine (fT3) were added. Anti-thyroperoxidase (TPO), anti-thyroglobulin (Tg) and thyroid stimulating immunoglobulin (TSI) levels were also performed at diagnosis, during and at the end of IFN therapy. All patients were assessed and followed up closely with monthly TSH, fT4 and fT3 levels until the completion, after 6 and 12 months of treatment.

RESULTS

There were seven females and four males over a 30-month period. All patients were found to have thyroiditis. On average, the time to the development of thyroid disease was 10 weeks and duration of disease 9 weeks. All patients eventually recovered normal biochemical thyroid function although two required short-term supplementation.

CONCLUSION

Thyroiditis was found exclusively in our patients. Both the hyper- and hypo-thyroid phase can be short lived, extreme and transient in nature which warrants strict monthly TSH monitoring. Careful follow-up of all patients is mandatory as complete recovery is expected.

The Spectrum of Autoimmune Thyroid Disease in the Short to Medium Term Following Interferon-alpha Therapy for Chronic Hepatitis C

Autoimmune thyroid diseases are common manifestations of hepatitis C infection, exacerbated by interferon-based treatment. However, the occurrence and pattern of thyroid disease in the short/medium term following the completion of IFN-based therapy is relatively unknown and there are very few previous reports regarding the specific spectrum of autoimmune thyroid disease that may follow such therapy. We hereby report 3 cases which demonstrate the range of thyroid diseases that may occur following interferon therapy. The hypothesis advanced is that in the pathogenesis of these conditions there must be both triggering and sustaining mechanisms as thyroid diseases occur well outside the immediate effect window of pegylated interferon. This paper suggests the need to continue thyroid surveillance in IFN-treated HCV patients following the completion of therapy, perhaps for the first 6 months.

Recognition of genetic factors influencing the progression of hepatitis C : potential for personalized therapy

Infection with hepatitis C virus (HCV) is a major cause of chronic liver disease. Hepatic fibrosis may develop in subjects with chronic HCV infection, culminating in cirrhosis and an increased risk of hepatocellular carcinoma. The rate of development of fibrosis varies substantially between individuals; while it is influenced by a number of demographic and environmental factors, these account for only a small proportion of the variability. There are no clinical markers or tests that predict the rate of fibrosis progression in an individual subject. Thus, there has been increasing interest in the influence of host genetic factors on the rate of disease progression, and whether a genetic signature can be developed to reliably identify individuals at risk of severe disease. Numerous case-control, candidate gene, allele-association studies have examined the relationship between host single nucleotide polymorphisms or other genetic mutations and fibrosis in patients with chronic HCV infection. However, these studies have generally been irreproducible and disappointing. As seen with genetic studies for other diseases, small study cohorts and poor study design have contributed to limited meaningful findings. The successful determination of genetic signatures for fibrosis progression in chronic HCV will require multicenter collaborations using genome-wide association studies, with large, phenotypically well-defined sample sets. While these studies will require a significant financial commitment, a successful outcome offers the potential for personalized therapy and better patient management.

Interferon autoantibodies associated with AIRE deficiency decrease the expression of IFN-stimulated genes

Neutralizing autoantibodies to type I, but not type II, interferons (IFNs) are found at high titers in almost every patient with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a disease caused by AIRE gene mutations that lead to defects in thymic T-cell selection. Combining genome-wide expression array with real time RT-PCR assays, we here demonstrate that antibodies against IFN-alpha cause highly significant down-regulation of interferon-stimulated gene expression in cells from APECED patients' blood by blocking their highly dilute endogenous IFNs. This down-regulation was lost progressively as these APECED cells matured in cultures without neutralizing autoantibodies. Most interestingly, a rare APECED patient with autoantibodies to IFN-omega but not IFN-alpha showed a marked increase in expression of the same interferon-stimulated genes. We also report unexpected increases in serum CXCL10 levels in APECED. Our results argue that the breakdown of tolerance to IFNs in AIRE deficiency is associated with impaired responses to them in thymus, and highlight APECED as another autoimmune disease with associated dysregulation of IFN activity.

HCV E2 protein binds directly to thyroid cells and induces IL-8 production: a new mechanism for HCV induced thyroid autoimmunity

HCV infection is well-known to be associated with autoimmune thyroiditis. However, the mechanisms by which HCV triggers thyroiditis are unknown. We hypothesized that HCV envelope proteins could induce thyroidal inflammation directly, thereby triggering thyroiditis by a bystander activation mechanism. To test this hypothesis we examined whether the HCV receptor CD81 was expressed and functional on thyroid cells. We found significant levels of CD81 mRNA by QPCR analysis, as well as CD81 protein by flow cytometric (FACS) analysis. Incubation of thyroid cells with HCV envelope glycoprotein E2 resulted in E2 binding to thyroid cells and activation of IL-8, an important pro-inflammatory cytokine. Intriguingly, thyroid cells incubated with E2 continued to proliferate normally and did not undergo apoptosis, as was reported in hepatocytes. We conclude that: (1) HCV envelope glycoprotein E2 can bind to CD81 receptors which are expressed on thyroid cells and induce a cascade of signaling pathway leading to IL-8 release; and (2) HCV may trigger thyroiditis in genetically susceptible individuals by bystander activation mechanisms.