Prevalence of thyroid autoantibodies is not increased in blood donors with hepatitis C virus infection

Environmental Issues in Thyroid Diseases

Environmental factors are determinant for the appearance of autoimmune thyroid diseases (AITD) in susceptible subjects. Increased iodine intake, selenium, and vitamin D deficiency, exposure to radiation, from nuclear fallout or due to medical radiation, are environmental factors increasing AITD. Cigarette smoking is associated with Graves' disease and Graves' ophthalmopathy, while it decreases the risk of hypothyroidism and thyroid autoimmunity. Viral infections are important environmental factors in the pathogenesis of AITD, too, particularly human parvovirus B19 (EVB19) and hepatitis C virus. Among the many chemical contaminants, halogenated organochlorines and pesticides variably disrupt thyroid function. Polychlorinated biphenyls and their metabolites and polybrominated diethyl ethers bind to thyroid transport proteins, such as transthyretin, displace thyroxine, and disrupt thyroid function. Among drugs, interferon- and iodine-containing drugs have been associated with AITD. Moreover intestinal dysbiosis causes autoimmune thyroiditis. To reduce the risk to populations and also in each patient, it is necessary to comprehend the association between environmental agents and thyroid dysfunction.

The role of human parvovirus B19 and hepatitis C virus in the development of thyroid disorders

The presence of viruses in the thyroid has been shown, but whether they are implicated in thyroid diseases or are only spectators is under investigation. The most important candidate viruses for autoimmune thyroid disorders (AITD) are hepatitis C virus (HCV) and human parvovirus B19 (or Erythrovirus B19 or EVB19). Retrospective and prospective case-control studies conducted on pathology slides showed (by PCR, in situ hybridization or immunohistochemistry) EVB19 was present in thyroid tissues of patients with autoimmune thyroiditis (AT), Graves' disease and thyroid cancer. Though AITD can be associated with acute EVB19 infection, it is not clear whether EVB19 could have a pathogenetic role in autoimmune thyroid diseases pathophysiology. Many studies have shown that frequently, patients with HCV chronic infection (CHC) show elevated serum anti-thyroperoxidase (TPOAb) and/or anti-thyroglobulin autoantibodies levels, ultrasonographic signs of chronic AT, and subclinical hypothyroidism. In patients with HCV-associated mixed cryoglobulinemia (MC + HCV), AITD were more prevalent with respect to controls, and also vs HCV patients without cryoglobulinemia. Papillary thyroid cancer was more prevalent in MC + HCV or CHC patients than in controls, especially in patients with AT. Recently it has been shown an elevated incidence of new cases of AT and thyroid dysfunction in MC patients. These results suggest an attentive monitoring of thyroid function and nodules in HCV patients with risk factors (female gender, a borderline high initial thyrotropin, TPOAb positivity, a hypoechoic and small thyroid) for the development of thyroid disorders.

Treatment of type 2 diabetes mellitus by viral eradication in chronic hepatitis C: Myth or reality?

Chronic hepatitis C is a systemic disease inducing metabolic alterations leading to extrahepatic consequences. In particular, hepatitis C virus (HCV) infection seems to increase the risk of incident type 2 diabetes mellitus in predisposed individuals, independently of liver disease stage. The mechanisms through which hepatitis C induces T2DM involve direct viral effects, insulin resistance, pro-inflammatory cytokines and other immune-mediated processes. Many studies have reported the clinical consequences of type 2 diabetes mellitus on hepatitis C outcome, but very few studies have addressed the issue of microangiopathic complications among patients with hepatitis C only, who develop type 2 diabetes mellitus. Moreover, clinical trials in HCV-positive patients have reported improvement in glucose metabolism after antiviral treatment; recent studies have suggested that this metabolic amelioration might have a clinical impact on type 2 diabetes mellitus-related complications. These observations raise the question as to whether the HCV eradication may also have an impact on the future morbidity and mortality due to type 2 diabetes mellitus. The scope of this review is to summarise the current evidence linking successful antiviral treatment and the prevention of type 2 diabetes mellitus and its complications in hepatitis C-infected patients.

Thyroid Peroxidase Antibodies in Non-Interferon Treated Hepatitis C Patients in Pakistan

Objective. Interferon therapy of HCV infected patients is associated with development of thyroid dysfunctions. Patients with pretreatment presence of antithyroid peroxidase (TPO-Ab) are at greater risk. This study, probably the first in Pakistan, was planned to determine TPO-Ab in sera of treatment-naive local HCV patients. Setting. Centre for Nuclear Medicine (CENUM), Mayo Hospital, Lahore. Patients and Methods. During July to December 2012, 190 patients (140 females, 50 males) newly diagnosed for HCV infection were selected for this study. Their age range was 15–55 years (mean: 35.3 ± 9.1 years). 262 age matched healthy subjects (211 females and 50 males) were recruited as control. Serum-free thyroxin (FT₄) and thyroid stimulating hormone (TSH) were detected by radioimmunoassay techniques. Serum TPO-Ab titer was determined by ELISA method using commercial kits. Results. Serum FT₄ and TSH levels in HCV patients and controls were within normal range. Between two groups there was no significant difference in mean value of FT₄ (16.0 ± 3.0 versus 16.2 ± 3.9; P = 0.619) but mean TSH value was significantly lower in HCV patients (1.5 ± 0.8 versus 1.8 ± 0.9; P = 0.003). Among HCV patients 51 (26.8%) were TPO-Ab positive and among control subjects 18 (6.9%) were TPO-Ab positive. The difference was statistically significant (P < 0.001). Further analysis showed that among HCV patients 39 (27.8%) females and 12 (24.0%) males were TPO-Ab positive, respectively, and difference was not statistically significant (P = 0.873). Moreover, TPO-Ab positive patients were older and had significantly higher serum TSH as compared to TPO-Ab negative HCV patients. Conclusion. Independent of patient's gender and increasing with advancing age, about one-fourth of local untreated HCV patients are TPO-Ab positive and are at greater risk of developing thyroid disorders during and after interferon treatment.

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.

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.

Thyroid disturbance related to chronic hepatitis C infection: role of CXCL10

Association between autoimmune thyroid diseases (AITD) and hepatitis C is controversial, but may occur or worsen during alpha-interferon treatment. The mechanism responsible for autoimmune diseases in infected patients has not been fully elucidated. This study aims to evaluate the frequency of AITD in chronic hepatitis C and the association of chemokine (CXC motif) ligand 10 (CXCL10) and AITD. One hundred and three patients with chronic hepatitis C and 96 controls were prospectively selected to clinical, hormonal, thyroid autoimmunity and ultrasound exams, besides thyroxine-binding globulin (TBG) and CXCL10 measurements and hepatic biopsies. The frequency of AITD among infected subjects was similar to controls. TT3 and TT4 distributions were right shifted, as was TBG, which correlated to both of them. Thyroid heterogeneity and hypoechogenicity were associated with AITD. Increased vascularization was more prevalent in chronic hepatitis C.CXCL10 was higher in infected patients (p=0.007) but was not related to thyroid dysfunction. Increase in CXCL10 levels were consistent with hepatic necroinflammatory activity (p=0.011). In summary, no association was found between chronic hepatitis C and AITD. Infected subjects had higher TT3 and TT4 which were correlated to TBG. Increased CXCL10 was not associated to thyroid dysfunction in HCV-infected population.

[Thyroid and hepatitis C]

Autoimmune thyroid diseases are complex diseases that develop as a result of interactions between genetic, epigenetic and environmental factors. IFNa therapy of chronic HCV infection is associated with subclinical or clinical thyroiditis, while the relationship between thyroiditis and virus C infection is still debated.

Prevalence of thyroid autoantibodies in hepatitis C and hepatitis B infection in China

OBJECTIVE

To explore the correlation between anti-thyroid autoantibodies and hepatitis C virus (HCV) infection.

METHODS

We collected 462 samples with positive thyroid peroxidase antibody (TPOAb) and/or thyroglobulin antibody (TgAb). Matched for age and gender, 380 subjects with negative TPOAb and TgAb were selected as controls. A third-generation enzyme linked immunosorbent assay (ELISA) was used to examine the presence of anti-HCV antibody. We also examined RNA HCV expression of subjects with positive anti-HCV antibody. Separate groups of 195 subjects with hepatitis C, 150 healthy subjects, and 150 subjects with hepatitis B were tested for thyroid-related markers.

RESULTS

The HCV infection rate was 1.30% in 462 subjects with positive thyroid autoantibodies, and 0.53% in 380 subjects who were negative for thyroid autoantibodies. There was no significant difference in the HCV infection rate between the two groups (χ(2)=1.322, p>0.05). In subjects with hepatitis C, 30.77% were TPOAb positive and 30.77% were TgAb positive; subjects with hepatitis C appeared to show significantly higher positivity of antithyroid autoantibodies when compared with healthy subjects and those with hepatitis B (χ(2)=21.496, χ(2)=30.454, p<0.01).

CONCLUSION

The HCV infection rate did not seem to be higher in subjects with abnormal thyroid autoimmunity. However, the positivity of thyroid autoantibodies appeared to be increased in subjects with hepatitis C, suggesting that thyroid-related markers should be examined in hepatitis C patients.

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.

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 etiology of autoimmune thyroid disease: a story of genes and environment

Autoimmune thyroid diseases (AITDs), including Graves' disease (GD) and Hashimoto's thyroiditis (HT) are prevalent autoimmune diseases, affecting up to 5% of the general population. Autoimmune thyroid diseases arise due to complex interactions between environmental and genetic factors. Significant progress has been made in our understanding of the genetic and environmental triggers contributing to AITD. However, the interactions between genes and environment are yet to be defined. Among the major AITD susceptibility genes that have been identified and characterized is the HLA-DR gene locus, as well as non-MHC genes including the CTLA-4, CD40, PTPN22, thyroglobulin, and TSH receptor genes. The major environmental triggers of AITD include iodine, medications, infection, smoking, and possibly stress. Recent data on the genetic predisposition to AITD lead to novel putative mechanisms by which the genetic-environmental interactions may lead to the development of thyroid autoimmunity.

Sustained virological response reduces incidence of onset of type 2 diabetes in chronic hepatitis C

Diabetes is present in patients with chronic hepatitis C virus infection. The aim of this retrospective cohort study was to assess the cumulative development incidence and predictive factors for type 2 diabetes after the termination of interferon therapy in Japanese patients positive for hepatitis C virus (HCV). A total of 2,842 HCV-positive patients treated with interferon (IFN) monotherapy or combination therapy with IFN and ribavirin were enrolled. The mean observation period was 6.4 years. An overnight (12-hour) fasting blood sample or a casual blood sample was taken for routine analyses during follow-up. The primary goal was the onset of type 2 diabetes. Evaluation was performed by using the Kaplan-Meier method and Cox proportional hazard analysis. Of 2,842 HCV patients, 143 patients developed type 2 diabetes. The cumulative development rate of type 2 diabetes was 3.6% at 5 years, 8.0% at 10 years, and 17.0% at 15 years. Multivariate Cox proportional hazard analysis revealed that type 2 diabetes development after the termination of IFN therapy occurred when histological staging was advanced (hazard ratio 3.30; 95% confidence interval [CI] 2.06-5.28; P < 0.001), sustained virological response was not achieved (hazard ratio 2.73; 95% CI 1.77-4.20; P < 0.001), the patient had pre-diabetes (hazard ratio 2.19; 95% CI 1.43-3.37; P < 0.001), and age was >or=50 years (hazard ratio 2.10; 95% CI 1.38-3.18; P < 0.001).

CONCLUSION

Our results indicate sustained virological response causes a two-thirds reduction in the risk of type 2 diabetes development in HCV-positive patients treated with IFN.

Hepatitis C virus enhances incidence of idiopathic pulmonary fibrosis

AIM: To investigate the cumulative development incidence and predictive factors for idiopathic pulmonary fibrosis in hepatitis C virus (HCV) positive patients.

METHODS: We studied 6150 HCV infected patients who were between 40-70 years old (HCV-group). Another 2050 patients with hepatitis B virus (HBV) were selected as control (HBV-group). The mean observation period was 8.0 ± 5.9 years in HCV-group and 6.3 ± 5.5 years in HBV-group. The primary goal is the development of idiopathic pulmonary fibrosis (IPF) in both groups. The cumulative appearance rate of IPF and independent factors associated with the incidence rate of IPF were calculated using the Kaplan-Meier method and the Cox proportional hazard model. All of the studies were performed retrospectively by collecting and analyzing data from the patient records in our hospital.

RESULTS: Fifteen patients in HCV-group developed IPF. On the other hand, none of the patients developed IPF in HBV-group. In HCV-group, the cumulative rates of IPF development were 0.3% at 10th year and 0.9% at 20th year. The IPF development rate in HCV-group was higher than that in HBV-group (P = 0.021). The IPF development rate in patients with HCV or HBV was high with statistical significance in the following cases: (1) patients ≥ 55 years (P < 0.001); (2) patients who had smoking index (package per day × year) of ≥ 20 (P = 0.002); (3) patients with liver cirrhosis (P = 0.042).

CONCLUSION: Our results indicate that age, smoking and liver cirrhosis enhance the development of IPF in HCV positive patients.

Interferon alpha treatment and thyroid dysfunction

Interferon alpha (IFN alpha) is the cornerstone therapeutic agent for chronic hepatitis C virus (HCV) infection. Prospective studies have shown that up to 15% of HCV patients receiving IFN alpha develop clinical thyroid disease, and up to 40% become thyroid antibody positive. In some cases IFN-induced thyroiditis (IIT) may result in discontinuation of interferon therapy; thus, IIT represents a major clinical problem for hepatitis C patients receiving IFN alpha therapy. Recently, the mechanisms leading to the development of IIT have begun to be unraveled. It is now clear that HCV itself plays a role in the disease. Moreover, recent data suggest the IFN alpha precipitates thyroiditis by both immune modulatory mechanisms and direct thyroid toxic effects. Genetic factors also play a major role in the etiology of IIT. IIT can manifest both as clinical autoimmune thyroiditis (ie, Hashimoto's thyroiditis and Graves' disease) and as nonautoimmune thyroiditis (ie, destructive thyroiditis). Early detection and therapy of these conditions are important to avoid complications of thyroid disease such as cardiac arrhythmias. This article reviews the epidemiology and clinical manifestations of IIT and the mechanisms causing IIT, focusing on the role of HCV.

Thyroid disorders in chronic hepatitis C virus infection

The prevalence of thyroid disorders has been evaluated in patients with hepatitis C virus (HCV) infection by many studies. From a review of the published controlled studies, it is possible to observe that: (1) most investigated patients with chronic HCV hepatitis, while a minority evaluated hepatitis C virus antibody (HCVAb)- seropositive patients (the two conditions are not comparable with regards to thyroidal repercussions, in fact, HCVAb-seropositive patients do not necessarily display changes of the immune system present in chronically infected HCV patients); and (2) some authors selected as internal control hepatitis B virus (HBV)-infected patients, while others selected apparently healthy controls or HCVAb-negative subjects. Pooling all data about HCV-positive patients (with chronic hepatitis or HCVAb positivity) and using as control the sum of healthy controls, HBV-infected patients and sera negative for HCVAb, a significant increase of the prevalence has been observed both for thyroid autoimmune disorders (odds ratio [OR] = 1.6; 95% confidence interval = [C]) 1.4-1.9) as well as for hypothyroidism (OR = 2.9; 95% CI = 2.0-4.1). The results of the epidemiologic studies showing an association between HCV infection and thyroid cancer need to be confirmed. The abovementioned evidences seem sufficient to suggest careful thyroid monitoring during the follow-up of patients with HCV infection.

The clinical and physiological spectrum of interferon-alpha induced thyroiditis: toward a new classification

Interferon-alpha (IFNalpha) is a major treatment modality for several malignant and nonmalignant diseases, especially hepatitis C. Prospective studies have shown that up to 15% of patients with hepatitis C receiving IFNalpha develop clinical thyroid disease, and up to 40% were reported to develop thyroid antibodies. Some of these complications may result in discontinuation of interferon therapy. Thus, interferon induced thyroiditis (IIT) is a major clinical problem for patients receiving interferon therapy. IIT can be classified as autoimmune type and non-autoimmune type. Autoimmune IIT may manifest by the development of thyroid antibodies without clinical disease, or by clinical disease which includes both autoimmune hypothyroidism (Hashimoto's thyroiditis) and autoimmune thyrotoxicosis (Graves' disease). Non-autoimmune IIT can manifest as destructive thyroiditis or as hypothyroidism with negative thyroid antibodies. Early detection and therapy of these conditions is important in order to avoid complications of thyroid disease such as cardiac arrhythmias. While it is not clear which factors contribute to the susceptibility to IIT, recent evidence suggests that genetic factors, gender, and hepatitis C virus infection may play a role. In contrast, viral genotype and therapeutic regimen do not influence susceptibility to IIT. The etiology of IIT is unknown and may be secondary to immune modulation by IFNalpha and/or direct effects of interferon on the thyroid. In this review we discuss the clinical and pathophysiological aspects of IIT, and we are proposing a new, etiology-based classification of IIT, as well as an algorithm for diagnosis and treatment of IIT.

Is hepatitis C virus a risk factor for thyroid autoimmunity?

The role of hepatitis C virus (HCV) in inducing thyroid autoimmunity is still under discussion and to assess the prevalence of thyroid autoantibodies and thyroid disease in the general population and to analyse the role of HCV in inducing thyroid autoimmunity. We studied 697 subjects residing in Arsita (a small town in central Italy). Thyroid autoantibodies and nonorgan-specific autoantibodies (NOSAs) were tested in each subject, who were also screened for anti-HCV antibodies; all subjects found positive to HCV-RNA were considered as being HCV-infected. Thyroid function tests were performed in all subjects positive for thyroid autoantibody. Seventy-one subjects were found HCV-positive; four of these (5.6%) were positive for at least one thyroid autoantibody, as opposed to 7 (4.9%) of the 142 sex- and age-matched controls of the same population (P = n.s.). Thyroid dysfunction was found in 2/4 HCV-positive, and in 1/7 HCV-negative subjects with thyroid autoantibodies (P = n.s.). NOSAs were significantly more common in HCV-positive than in HCV-negative subjects (P < 0.0001). Hence HCV per se is not responsible for thyroid autoimmune dysfunction, whereas HCV does seem to induce NOSAs. It should be taken into account, however, that the phenotypic expression of autoimmune diseases is obviously influenced by a number of risk factors, including genetic predisposition, female sex and infectious agents, that could trigger the onset of the disease.

Usefulness of the serum KL-6 assay in patients with hepatitis C virus

OBJECTIVE

The aim of this study is to evaluate the serum level of KL-6 in hepatitis C virus (HCV)-positive patients with chronic liver disease.

METHODS AND RESULTS

Subjects consisted of 502 HCV-positive patients. The serum samples of these patients stored at -80 degrees C were measured by enzyme-linked immunosorbent assay for KL-6 at the same time. The cutoff point of the serum KL-6 level was defined as 500 U/ml. The serum KL-6 level of the 502 patients ranged between 71 and 2,295 (median, 223) U/ml. Thirty-two of the 502 (6.4%) patients showed an elevated KL-6 level of >500 U/ml. Three of the 32 (9.4%) patients with elevated KL-6 level >500 U/ml had idiopathic pulmonary fibrosis. Multivariate analysis showed that patients achieved elevated KL-6 when: (1) they had hepatocellular carcinoma (HCC; p = 0.0007), and (2) age was >60 years (p = 0.0085). The HCC rate was 37.5% (12/32) in the patients with elevated KL-6 and 8.3% (39/470) in the patients with normal KL-6 group. The median (range) age was 70 (56-77) years in the patients with elevated KL-6 group and 60 (12-92) years in the patients with normal KL-6.

CONCLUSION

The patients with HCC aged >60 years had significantly elevated serum levels of KL-6.

Interferon induced Autoimmune Thyroid Disease (AITD): a model for human autoimmunity

Interferon (IFN) alpha treatment for various conditions has been associated with thyroid autoimmunity. The incidence of interferon induced thyroid autoimmunity has been reported to range from 2.5% to 42%, possibly depending upon dose and duration of medical therapy and patient characteristics. It is not known whether IFN-alpha initiates autoimmune thyroid disease (AITD) or simply exacerbates AITD in individuals with subclinical AITD.

Extrahepatic manifestations of hepatitis C infection

Hepatitis C virus (HCV) affects 1.8% of the American population, and approximately 38% of patients with HCV will manifest symptoms of at least 1 extrahepatic manifestation during the illness. Renal disease, neuropathy, lymphoma, and Sjögren syndrome with or without mixed cryoglobulinemia are all strongly associated with HCV infection. Porphyria cutanea tarda and diabetes have also been linked to HCV. Most extrahepatic manifestations of chronic HCV infection are immunological, and the chronic infection seems to be necessary for their development. The molecular study of the unique way in which the HCV virus interacts with the human immune system is beginning to provide plausible explanations of the pathogenic role of HCV in some of these syndromes, but many pathogenetic links remain completely obscure.

Thyroid autoimmunity in chronic idiopathic urticaria: implications for therapy

The association between thyroid autoimmunity and chronic idiopathic urticaria has long been recognized, although prevalence rates differ in the studies reported to date (from 12 to 29%). There is, therefore, a strong indication to screen patients affected by chronic urticaria of unknown origin for thyroid antibodies (antithyroperoxidase and antithyroglobulin) and, when positive, for serum thyrotropin to assess thyroid functional status. Less clear is the implication of thyroid autoimmunity for therapy, as most patients with urticaria who have associated thyroid autoimmunity are euthyroid. There is no doubt that cases with clinical or subclinical thyroid dysfunction should undergo treatment with either levothyroxine or antithyroid drugs for hypo- or hyper-function, respectively. Although the best remission rates for symptoms of urticaria have so far been obtained with levothyroxine in patients who are euthyroid, monitoring of thyroid function through serum thyrotropin determination is highly recommended because of the risk of hyperthyroidism, especially in the elderly.

Disease associations with autoimmune thyroid disease

Autoimmune thyroid disease (AITD) is common and occurs frequently in conjunction with other diseases. Many putative disease associations have been suggested for AITD but the validity of these associations is not clear in all cases. It is important to define disease associations correctly because this may offer a means to rationally screen for true associations, may shed light on shared pathophysiologic mechanisms and may be important if the associated disease impacts on patient management. This review has examined the evidence base for a large number of the suggested associations.

Impact of treatment on extra hepatic manifestations in patients with chronic hepatitis C

BACKGROUND/AIMS

Fatigue and other extra hepatic manifestations of hepatitis C have never been studied prospectively in a large cohort. The aim was to assess the prevalence of these symptoms prior to any treatment, and on prolonged follow-up in treated and untreated patients.

METHODS

A single-center cohort of consecutive patients with chronic hepatitis C was investigated prior to any treatment. A questionnaire was completed every 6 months for 18 months of follow-up.

RESULTS

Of 1614 patients, 431 met the inclusion criteria (56% male; age 49 years; 60% with significant fibrosis or cirrhosis; 46% with cryoglobulinemia). Seventy-six were untreated; of the treated patients, 83 were sustained responders, 47 relapsers and 225 non-responders. At baseline, fatigue and other extrahepatic manifestations were present in 254 (59%) and 225 (52%) patients. Fatigue was improved in 29 of 83 (35%) responders versus 75 of 348 (22%) patients with detectable hepatitis C virus (HCV)-RNA (P=0.01). The impact of virologic response on fatigue persisted after adjusting for age, gender, fibrosis stage, and depression (odds ratio: 0.34, P<0.001). A cryoglobulin was detectable in two of 34 (6%) responders versus 38 of 115 (33%) patients with detectable HCV-RNA (P<0.001).

CONCLUSIONS

In hepatitis C, a sustained virologic response is associated with a reduction in fatigue and cryoglobulin, but fatigue frequently persists despite a virologic response.

Polyspecificity of antimicrosomal thyroid antibodies in hepatitis C virus-related infection

OBJECTIVES

The outcome of dysthyroidism and the presence of antithyroid antibodies in patients with chronic hepatitis C virus (HCV) infection receiving interferon-alpha therapy is clearly established. However, the prevalence and the specificity of antithyroid antibodies in HCV patients before interferon-alpha therapy remain controversial. The aim of the present study is to clarify within a large population of HCV patients the prevalence of antithyroid antibodies before interferon-alpha therapy and to determine whether their immunodominant antigen is the same as described in autoimmune thyroiditis.

METHODS

Sera from 99 patients with chronic hepatitis C before (n = 99) and after (n = 37) interferon-alpha treatment were investigated for the presence of antimicrosomal and antithyroperoxidase antibodies assessed by indirect immunofluorescence and ELISA, respectively. Dot blotting on human thyroid lysate was designed to further characterize these autoantibodies. Data were compared to those obtained with sera of patients with autoimmune thyroiditis (n = 75) and healthy subjects (n = 96).

RESULTS

In HCV patients, antimicrosomal antibodies were found with a higher proportion before interferon-alpha therapy (12.1%) than after therapy (8%). Thyroperoxidase constitutes the main antigen in only 4% before treatment, a prevalence similar to that observed in healthy controls.

CONCLUSIONS

The prevalence of antithyroid antibodies is low in patients with chronic hepatitis C before interferon-alpha therapy. Thyroperoxidase may not be their main target. Further studies are required to determine whether HCV infection leads to a breakdown of tolerance to a thyroid self-protein other than thyroperoxidase.

Islet cell and thyroid antibody prevalence in patients with hepatitis C virus infection: effect of treatment with interferon

An increased prevalence of hepatitis C virus (HCV) infection in patients with diabetes and a higher prevalence of diabetes in HCV-infected patients have been reported. However, the relationship between these two conditions remains controversial. In addition, although the effect of interferon treatment on thyroid autoimmunity has been extensively reported, its influence on beta-cell autoantibodies has not been investigated. The aims of the study were (1) to evaluate whether autoimmune beta-cell damage could be involved in the development of diabetes mellitus in HCV-infected patients and (2) to determine whether interferon treatment influences the appearance of beta-cell and thyroid autoantibodies. The prevalence of islet cell autoantibodies (glutamic acid decarboxylase antibodies [GADAs], tyrosine phosphatase antibodies [IA-2s], islet cell antibodies [ICAs]) was assessed in 303 non-selected HCV-infected patients (277 non-diabetic and 26 type 2 diabetic patients) and in 273 sex- and age-matched control subjects. ICAs and thyroid autoantibodies were also determined before and 6 and 12 months after treatment with interferon for 24 weeks in a subgroup of 46 HCV-infected patients. GADAs were detected in 4 of 277 (1.4%) HCV-infected non-diabetic patients, 1 of 273 (0.3%) control subjects, and 0 of 26 (0%) HCV-infected patients with diabetes. Anti-IA2s and ICAs were negative in all subjects. Both GADAs and anti-IA2s were negative in all HCV-infected patients treated with interferon. After therapy, only thyroid antibodies became positive in 5 of 46 (10.9%) treated patients, disappearing in all but 1 of these at the 12-month follow-up. Our results suggest that beta-cell autoimmunity is not associated with HCV infection, thus making it unlikely that the increased diabetes mellitus prevalence among HCV-infected patients could be mediated by autoimmune mechanisms. In addition, interferon treatment induces a transient increase in thyroid autoantibodies but does not influence the appearance of beta-cell autoantibodies.

Independent expression of serological markers of thyroid autoimmunity and hepatitis virus C infection in the general population: results of a community-based study in north-western Sardinia

To assess the relationship between serological markers of thyroid autoimmunity and chronic hepatitis C, we surveyed the general population of two villages in the region of Sardinia, Italy, where infection with hepatitis viruses is endemic and the prevalence of autoimmune diseases is elevated. A total of 1310 subjects aged 6-88 years (65% of the total resident population) participated in the survey, and 1233 (94%; 444 males and 789 females) agreed to provide a blood sample. Autoantibodies to thyroid peroxidase (anti-TPO) were measured by radioimmunoassay; antibodies to HCV (anti-HCV) by a third generation enzyme immunoassay and borderline positive results confirmed by recombinant immunoblot assay. For both anti-HCV and anti-TPO the age- and gender-standardized prevalence rates (SPR) were calculated and the significance of the association between the two antibodies tested by Yates corrected chi2 test. The overall SPR for anti-HCV was 50.7x10(-3) (86/1,233), similar between men [49.1x10(-3) (22/444)] and women [52.3x10(-3) (64/789)]. The overall SPR for anti-TPO was 136.9x10(-3) (204/1,233), and that among women [201x10(-3) (174/789)] was almost 3-fold that among men [71.6x10(-3) (30/444)]. A concurrent anti-HCV and anti-TPO positivity was found in a small minority of subjects [8/1,233 (0.65%)], all women aged 57-81 years. The SPR for the two concurrent events was 3.3x10(-3), which was not significantly different (Yates corrected chi2 test = 0.65) from that expected under the assumption of unrelated events. To explore whether HCV infection is a risk factor for anti-TPO positivity, we designed a case-control study with anti-TPO positive subjects as the cases, and anti-TPO negative subjects as the controls. The age- and gender-adjusted odd ratio (OR) was 0.4 (95% CI 0.2,0.7), indicating a negative association. In conclusion, no evidence for epidemiological association of circulating thyroid autoantibodies and antibodies to HCV was found. Our findings do not therefore support a pathogenetic link between HCV infection and thyroid autoimmunity.

[Hepatitis C virus infection and thyroid diseases]

INTRODUCTION

The combination of hepatitis C virus (HCV) infection and thyroid diseases raises several issues that are the prevalence of thyroid autoimmunity in patients with chronic hepatitis C, the prevalence of HCV infection in patients with autoimmune thyroid diseases, and the effects of interferon alpha treatment on thyroid function in chronic HCV hepatitis.

CURRENT KNOWLEDGE AND KEY POINTS

The prevalence of anti-thyroid auto-antibodies ranges from 4.6 to 15% in HCV infection, which is considered as significant by various authors. Results have to be interpreted according to the following: the type of auto-antibodies detected, the age, sex, ethnic origin of the population studied, and characteristics of the control population. Recent data are suggestive of a high prevalence of anti-thyroid auto-antibodies in females with HCV infection. An increased prevalence of HCV infection in patients with Hashimoto's thyroiditis is not confirmed. During treatment of chronic hepatitis C, interferon alpha induces thyroid dysfunctions (3 to 15% of the cases) with various clinical presentations. Hypothyroidism is more common (two out of three cases) than hyperthyroidism (one out of three cases). Hyperthyroidism followed by hypothyroidism has also been described. Clinical symptoms vary, ranging from subclinical to severe manifestations. Thyroid dysfunction may be delayed after discontinuation of the interferon treatment. Hypothyroidism is easily cured by L-thyroxine replacement therapy when necessary, and regression may be observed following discontinuation of interferon treatment. Each case of hyperthyroidism has to be precisely evaluated. Development of anti-thyroid antibodies or an increase in anti-thyroid antibodies titers is often observed during interferon alpha treatment, thus suggesting the existence of immunological mechanisms at the origin of thyroid dysfunction. Furthermore, interferon would directly act on iodine.

FUTURE PROSPECTS AND PROJECTS

Clinical studies are still necessary to better clarify the links between HCV infection and thyroid autoimmunity, and to determine risk factors for the development of thyroid dysfunction during interferon alpha therapy. The effects of HCV and interferon alpha on thyroid autoimmunity and function have to be investigated in basic research.

[Does hepatitis c virus-related autoimmune thyroiditis exist? Reflections on a controlled study of 58 consecutive subjects]

PURPOSE

Interferon alpha treatment for virus C hepatitis may be responsible for autoimmune thyroiditis. Relationships between thyroiditis and virus C infection are still debated. The aim of this study was to evaluate the existence of this association.

METHODS

The prevalence of autoimmune thyroiditis in 58 patients (35 male and 23 female patients, mean age 52.6) with untreated virus C hepatitis was compared to that of 56 alcoholic patients (41 male and 15 female patients, mean age 53.8). Autoimmune thyroiditis was defined as the association of abnormal TSH and an increase in antithyroid antibodies.

RESULTS

We did not find any statistical difference in either autoimmune thyroiditis or antithyroid antibodies prevalences.

CONCLUSION

Both our results and a literature review suggest that the few reported cases of related autoimmune thyroiditis and virus C infection are probably coincidental.

Hepatitis C-associated autoimmune disorders

Hepatitis C virus (HCV) infection has been associated with multiple autoimmune manifestations. The immune response to HCV infection encompasses the development of autoantibodies, immune complex formation and deposition, and cryoglobulinemia complicated by vasculitis, glomerulonephritis, or neuropathy. HCV infection has been associated with antiphospholipid antibody syndrome, RA, SLE, PM/DM, and thyroid disease. HCV-infected patients also have a high incidence of sicca symptoms with sialoadenitis, and reports of low-grade lymphoproliferative malignancies have emerged. Optimal treatment for HCV-related autoimmune disease remains to be determined, but patients seem to respond to immunosuppression with classic agents or interferon.

Clinical manifestations of hepatitis C

Hepatitis C is a common cause of viral hepatitis that progresses to chronic infection in the majority of patients. Clinically, the infection is generally asymptomatic, but it may present with a wide variety of symptoms. Cirrhosis, hepatocellular carcinoma, cryoglobulinemia, auto-antibodies, and glomerulonephritis have been strongly associated with HCV. There is a probable association with autoimmune disease and NHL. More information is needed to determine whether lichen planus, PCT, and other disorders are part of the growing clinical spectrum or just coincidental associations with chronic liver disease.

Failure to find an association between hepatitis C virus and thyroid autoimmunity

A high frequency of hepatitis C antibodies has been reported from France in patients with autoimmune thyroiditis. Two cases of Hashimoto's thyroiditis in association with chronic active hepatitis and hepatitis C infection have also been reported. We have examined this potential association in 46 patients with autoimmune hypothyroidism and found that 16 apparently had hepatitis C antibodies in one of the two commercially available enzyme-linked immunosorbent assays (ELISA), but all patients were negative in a confirmatory commercially available recombinant immunoblot assay (RIBA-3) indicating that none of the patients were truly positive for hepatitis C antibodies. We also tested sera from 111 patients with proven hepatitis C infection and found no increased prevalence of thyroid autoantibodies. These results suggest that hepatitis C infection is not a risk factor for the development of thyroid autoimmunity in the United Kingdom.

Hepatitis C virus infection and autoimmunity

Hepatitis C virus (HCV) infection has been associated with a plethora of immune and autoimmune perturbations. We review serological and clinical autoimmune manifestations associated with HCV infection, discuss treatment regimens for HCV-related autoimmune diseases, and present a framework for understanding HCV-associated autoimmune disease by performing a computerized literature search from which representative articles were used and referenced. The immune response to HCV may include the development of cryoglobulins, rheumatoid factor, antinuclear antibodies (ANA), anticardiolipin, antithyroid, anti-liver/kidney/microsomal antibodies (anti-LKM), as well as HCV/anti-HCV immune complex formation and deposition. HCV infection is a significant cause of mixed essential cryoglobulinemia, which may then be complicated by cryoglobulinemic glomerulonephritis, vasculitis, or neuropathy. It has also been associated with membranous and membranoproliferative glomerulonephritis. Subsets of autoimmune hepatitis patients are infected with HCV and evidence suggests that HCV is a causative agent of antithyroid antibodies and autoimmune thyroid disease. Although cause-and-effect remain to be proved, there are reports of HCV infection preceding or coincident with polyarthritis, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and polymyositis/dermatomyositis (PM/DM). HCV-infected patients also have a high incidence of sialoadenitis, and reports of low-grade lymphoproliferative malignancies have emerged. However, HCV is not a major causative factor for most autoimmune diseases. Optimal treatment for HCV-related autoimmune disease remains to be determined. Interferon alpha (IFN alpha) has successfully reduced viremia/transaminitis, cryoglobulins, proteinuria, and nephritis, but recurrent disease manifestations are frequent after discontinuation of therapy. Moreover, IFN alpha may precipitate or exacerbate autoimmune disease symptoms. HCV-related autoimmune disease also has been treated successfully with corticosteroids, azathioprine, and cyclophosphamide, although HCV viremia persists and may worsen.

Nonhepatic manifestations and combined diseases in HCV infection

Infection with hepatitis C virus (HCV) may affect not only the liver but also various nonhepatic tissues and organs and may combine with many etiologically unrelated diseases and morbid conditions. Numerous nonhepatic manifestations in HCV infection have been previously reported. For some (eg, cryoglobulinemia), the association is well established. For others, such as sialadenitis and lichen planus, the association is probable (but not completely documented) and, for the remainder, the associations are weak. Extrahepatic manifestations may result from immunological mechanisms as well as virus invasion and replication in the affected extrahepatic tissues and organs. Thyroid abnormalities, primarily Hashimoto's disease, and isolated increases of anti-thyroid antibodies (ATPO) appear to be more frequent in chronic hepatitis C than B or D, with high ATPO titers clustering mainly among females. Interferon-alpha (IFN-alpha) therapy is associated with development of thyroid dysfunction in 5.5-12.9% of patients, usually exposing preexisting subclinical thyroid abnormalities. Mixed cryoglobulinemia (MC) is commonly found (36-45%) in patients with chronic HCV infection; however, only in a minority of cases does it become clinically manifested as systemic vasculitis with purpura, neuropathy, or Raynaud's phenomenon. In a number of patients, MC may terminate in non-Hodgkin's B-cell lymphoma. Treatment of these lymphoproliferative disorders with IFN-alpha is advocated. Idiopathic thrombocytopenia is now recognized more frequently in association with chronic HCV infection and is usually aggravated by IFN-alpha therapy. Patients with porphyria cutanea tarda (PCT) have demonstrated serological markers of HCV infection in 62-82% of cases. The usefulness of IFN-alpha in PCT remains to be demonstrated. Lichen planus has also been found in association with chronic HCV infection, particularly when severe or affecting the oral cavity. Other nonhepatic manifestations have also been reported in HCV infection such as diabetes, corneal ulceration, uveitis, and sialadenitis. These manifestations deserve further study and documentation. Finally, markers of autoimmunity occur with high frequency in chronic HCV infection; however, combination with the classical syndrome of autoimmune hepatitis is rare. In the presence of various autoantibodies, the clinical features of chronic hepatitis C do not appear to be modified and, contrary to general perception, IFN-alpha therapy within randomized controlled trials should not be withheld since the response rate to IFN-alpha does not appear to differ in the presence or absence of low titers of these markers.