Thyroid disorders in chronic hepatitis C virus infection

Thyroid Autoimmunity and SARS-CoV-2 Infection

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological culprit of COronaVIrus Disease 19 (COVID-19), can enter the cells via the angiotensin-converting enzyme 2 (ACE2) receptor, which has been found in several tissues including in endocrine organs, such as the ovaries, testes, pancreas, and thyroid. Several thyroid disorders have been associated with SARS-CoV-2 infection [subacute thyroiditis (SAT), thyrotoxicosis, and non-thyroidal illness syndrome (NTIS)] and, in part, they are believed to be secondary to the local virus replication within the gland cells. However, as documented for other viruses, SARS-CoV-2 seems to interfere with several aspects of the immune system, inducing the synthesis of autoantibodies and triggering latent or new onset autoimmune disease (AID), including autoimmune thyroid disease (AITD), such as Hashimoto Thyroiditis (HT) and Graves' disease (GD). Several mechanisms have been hypothesized to explain this induction of autoimmunity by SARS-CoV-2 infection: the immune system hyper-stimulation, the molecular mimicry between the self-antigens of the host and the virus, neutrophils extracellular traps, and finally, the virus induced transcriptional changes in the immune genes; nonetheless, more evidence is needed especially from large, long-term cohort studies involving COVID-19 patients, to establish or reject this pathogenetic relationship.

Human T-cell leukemia virus type 1 is associated with dysthyroidism in the French Amazon

Background

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus known to cause two major diseases: adult T-cell leukemia/lymphoma and a progressive neuromyelopathy-tropical spastic paraparesis. Many viruses may be involved in the pathogenesis of thyroiditis; however, few studies have focused on the role of HTLV-1. We aimed to investigate the association between HTLV-1 and biological thyroid dysfunction.

Methods

We included 357 patients with a positive HTLV-1 serology and thyroid-stimulating hormone assay data between 2012 and 2021 in a hospital in French Guiana; we compared the prevalence of hypothyroidism and hyperthyroidism in this group with that in an HTLV-1-negative control group (722 persons) matched for sex and age.

Results

The prevalence of hypothyroidism and hyperthyroidism in patients with HTLV-1 infection was significantly higher than that in the control group (11% versus 3.2% and 11.3% versus 2.3%, respectively; p < 0.001).

Conclusion

Our study shows, for the first time, the association between HTLV-1 and dysthyroidism in a large sample, suggesting that thyroid function exploration should be systematically implemented in this population as this may have an impact on therapeutic management.

COVID-induced thyroid autoimmunity

Breakdown of self-tolerance to thyroid antigens (thyroperoxidase, thyroglobulin and the thyrotropin-receptor) is the driver of thyroid autoimmunity. It has been suggested that infectious disease might trigger autoimmune thyroid disease (AITD). Involvement of the thyroid has been reported during severe acute respiratory syndrome virus 2 (SARS-CoV-2) infection, in the form of subacute thyroiditis in subjects with mild coronavirus disease 19 disease (COVID-19) and of painless, destructive thyroiditis in hospitalized patients with severe infection. In addition, cases of AITD, both Graves' disease (GD) and Hashimoto's thyroiditis (HT), have been reported in association with (SARS-CoV-2) infection. In this review, we focus on the relationship between SARS-CoV-2 infection and occurrence of AITD. Nine cases of GD strictly related to SARS-CoV-2 infection and only three cases of HT associated to COVID-19 infection have been reported. No study has demonstrated a role of AITD as a risk factor for a poor prognosis of COVID-19 infection.

Different profiles of neurocognitive impairment in patients with hepatitis B and C virus infections

The direct impact of chronic hepatitis B and hepatitis C on neurocognition remains elusive due to the frequent comorbidities, and the domains of the neurocognitive functions affected have rarely been investigated comprehensively. We cross-sectionally assessed the neurocognitive functions of the individuals with chronic hepatitis B, chronic hepatitis C, treated chronic hepatitis C with a sustained virologic response, and their healthy control counterparts. Laboratory examinations were used to investigate the impact of inflammation on neurocognition, exclude the medical conditions that could interfere with neurocognition assessment, and assess liver function and fibrotic severity of the liver of the participants. This study found the detrimental impact of chronic hepatitis B on language and executive functions. In contrast, individuals with chronic hepatitis C showed deficits in executive functions, psychomotor speed, memory, and attention. Successful elimination of hepatitis C resulted in improved liver function, but not neuropsychological test performance. Moreover, erythrocyte sedimentation rate level was found to mediate the deficits in the attention of individuals with chronic hepatitis C. These results demonstrate the neurocognitive deficits and the difference in the profiles of neurocognitive deficits in individuals with chronic hepatitis B and chronic hepatitis C. Our study also provided results suggesting the mediation by systemic inflammation on the attention deficit in individuals with chronic hepatitis C.

The association of hepatitis C virus infection and thyroid disease: A systematic review and meta-analysis

Previous studies have reported that hepatitis C virus (HCV) infection may increase the risk of thyroid disease (TD) even thyroid cancer (TC), but quantitative assessments of risk were rare and the results were not consistent. The purpose of this study was to evaluate the impact of HCV infection on TD and TC, and provide clues to explore the relationship between HCV infection and TD and TC. The literature retrieval was performed up to August 20th, 2021 in the database of PubMed, Cochrane library, Web of Science, China National Knowledge Infrastructure and Wang Fang. The risk of HCV for TD or TC was expressed with odds ratio (OR) and 95% confidence intervals (CI). Subgroup analysis was used to explore the source of heterogeneity. Six articles (three studies published as article and three studies published as abstract) were included in this meta-analysis, with a total of 5398 controls and 1925 cases of hepatitis C. The results of meta-analysis found that HCV infection were significantly associated with an increased risk of TD (sum OR = 1.80, 95% CI = 1.54-2.10, P <  0.001, I² = 74.3%) and TC (sum OR = 16.36, 95% CI = 4.65-57.62, P < 0.001, I² = 0%). HCV infection may increase the risk of TD and TC. More work is needed in the future to establish a causal role, however an awareness of the possibility of increased risk of TD and TC may lead to earlier diagnosis and better outcomes in patients with hepatitis C.

Autoantibodies and Rheumatologic Manifestations in Hepatitis C Virus Infection

HCV is a virus that can cause chronic infection which can result in a systemic disease that may include many rheumatologic manifestations such as arthritis, myalgia, sicca syndrome, cryoglobulinemia vasculitis as well as other non-rheumatological disorders (renal failure, onco-haematological malignancies). In this population, the high frequency of rheumatoid factor (45-70%), antinuclear (10-40%) and anticardiolipin (15-20%) antibodies is a B-cell mediated finding sustained by the infection. However, the possibility that a primitive rheumatic pathology may coexist with the HCV infection is not to be excluded thus complicating a differential diagnosis between primitive and HCV-related disorders.

Insights from a Prospective Follow-up of Thyroid Function and Autoimmunity among COVID-19 Survivors

BACKGROUND

The occurrence of Graves' disease and Hashimoto thyroiditis after coronavirus disease 2019 (COVID-19) raised concerns that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may trigger thyroid autoimmunity. We aimed to address the current uncertainties regarding incident thyroid dysfunction and autoimmunity among COVID-19 survivors.

METHODS

We included consecutive adult COVID-19 patients without known thyroid disorders, who were admitted to Queen Mary Hospital from July 21 to September 21, 2020 and had serum levels of thyroid-stimulating hormone, free thyroxine, free triiodothyronine (fT3), and anti-thyroid antibodies measured both on admission and at 3 months.

RESULTS

In total, 122 patients were included. Among 20 patients with abnormal thyroid function tests (TFTs) on admission (mostly low fT3), 15 recovered. Among 102 patients with initial normal TFTs, two had new-onset abnormalities that could represent different phases of thyroiditis. Among 104 patients whose anti-thyroid antibody titers were reassessed, we observed increases in anti-thyroid peroxidase (TPO) (P<0.001) and anti-thyroglobulin (P<0.001), but not anti-thyroid stimulating hormone receptor titers (P=0.486). Of 82 patients with negative anti-TPO findings at baseline, 16 had a significant interval increase in anti-TPO titer by >12 U, and four became anti-TPO-positive. Worse baseline clinical severity (P=0.018), elevated C-reactive protein during hospitalization (P=0.033), and higher baseline anti-TPO titer (P=0.005) were associated with a significant increase in anti-TPO titer.

CONCLUSION

Most patients with thyroid dysfunction on admission recovered during convalescence. Abnormal TFTs suggestive of thyroiditis occurred during convalescence, but infrequently. Importantly, our novel observation of an increase in anti-thyroid antibody titers post-COVID-19 warrants further follow-up for incident thyroid dysfunction among COVID-19 survivors.

Hepatocrinology

Hepatocrinology is defined as a bidirectional, complex relationship between hepatic physiology and endocrine function, hepatic disease and endocrine dysfunction, hepatotropic drugs and endocrine function, and endocrine drugs and hepatic health. The scope of hepatocrinology includes conditions of varied etiology (metabolic, infectious, autoimmune, and invasive) that we term as hepato-endocrine syndromes. This perspective shares the definition, concept, and scope of hepatocrinology and shares insight related to this aspect of medicine. It is hoped that this communication will encourage further attention and research in this critical field.

Microorganisms associated to thyroid autoimmunity

Autoimmune thyroid diseases are a group of diseases characterized by a dysfunction of the immune system concerning the thyroid gland, associated with hypothyroidism or hyperthyroidism. The thyroid gland autoimmunity has been recognized as multifactorial. It has been reported that microorganisms may play a role on the pathogenesis of Hashimoto's thyroiditis and Graves´ disease. These could explain the high incidence of the autoimmune thyroid diseases. Helicobacter Pylori (H. pylori) and Hepatitis C virus (HCV) are the microorganisms in which the association with autoimmune thyroid diseases is clearer. The pathophysiologic mechanisms are still not well defined. For H. pylori, molecular mimicry has been the most accepted mechanism. It has been proposed Hepatitis C virus as the trigger of the thyroid autoimmunity by exacerbating the production of thyroid auto-antibodies, while some mention that the real factor that triggers the thyroid autoimmunity is the treatment with Interferon alpha (IFN-alpha) by upregulating MHC class I and inducing ligation of CD40+ cells to thyrocytes. Other microorganisms such as Toxoplasma gondii, Human Immunodeficiency virus, Herpes virus and others have reported information about their association with thyroid autoimmune diseases There are no proposals on how these last microorganisms induce thyroid autoimmunity. There is still a lack of evidence on this topic. Further research must be done to determine the interaction of these microorganisms and the best way to manage these patients.

The interplay between thyroid and liver: implications for clinical practice

A complex relationship exists between thyroid and liver in health and disease. Liver plays an essential physiological role in thyroid hormone activation and inactivation, transport, and metabolism. Conversely, thyroid hormones affect activities of hepatocytes and hepatic metabolism. Serum liver enzyme abnormalities observed in hypothyroidism may be related to impaired lipid metabolism, hepatic steatosis or hypothyroidism-induced myopathy. Severe hypothyroidism may have biochemical and clinical features, such as hyperammonemia and ascites, mimicking those of liver failure. Liver function tests are frequently abnormal also in hyperthyroidism, due to oxidative stress, cholestasis, or enhanced osteoblastic activity. Antithyroid drug-associated hepatotoxicity is a rare event, likely related mainly to an idiosyncratic mechanism, ranging from a mild hepatocellular damage to liver failure. Propylthiouracil-induced liver damage is usually more severe than that caused by methimazole. On the other hand, thyroid abnormalities can be found in liver diseases, such as chronic hepatitis C, liver cirrhosis, hepatocellular carcinoma, and cholangiocarcinoma. In particular, autoimmune thyroid diseases are frequently found in patients with hepatitis C virus infection. These patients, especially if thyroid autoimmunity preexists, are at risk of hypothyroidism or, less frequently, thyrotoxicosis, during and after treatment with interpheron-alpha alone or in combination with ribavirin, commonly used before the introduction of new antiviral drugs. The present review summarizes both liver abnormalities related to thyroid disorders and their treatment, and thyroid abnormalities related to liver diseases and their treatment.

Frequent occurrence of low-level positive autoantibodies in chronic hepatitis C

Evidence of autoimmune disease associated with hepatitis C virus (HCV)-infection has important clinical implications. A systematic profile of these autoantibodies in relevant clinical cohorts relative to healthy controls is needed to better inform current standard of care for chronic hepatitis C. Samples from an Australian cohort of chronic HCV-infected subjects (n=127) were tested for the presence of 19 diagnostic autoantibodies and compared with data available from a control cohort representing a general Caucasian population (n=198). Chronic HCV-infected individuals had a greater number of autoantibodies than controls (p<0.0001). Anti-nuclear antibodies (ANA) followed by anti-smooth muscle antibodies (SMA) were the most frequently detected autoantibodies within the HCV cohort and significantly more than in the control cohort (p<0.0001 and p=0.006, respectively). However, for most autoantibody assays the 95th percentile approximated the reference value for positivity. None of the autoantibodies were significantly associated with age or sex for the HCV cohort, except SMA positivity that was significantly higher in chronic HCV-infected male subjects (p<0.0001). Autoantibodies found in chronic HCV-infected subjects were commonly low positive and not disease-specific. Accordingly, general screening for autoimmunity in HCV-infected subjects should not be performed unless there is high clinical suspicion of an underlying autoimmune disease.

Maternal Hepatitis B Virus or Hepatitis C Virus Carrier Status and Long-Term Endocrine Morbidity of the Offspring-A Population-Based Cohort Study

This study aimed to investigate the long-term effect of maternal hepatitis B virus (HBV) or hepatitis C virus (HCV) carrier status on offspring endocrine morbidity. A population-based cohort study included all singleton deliveries between the years 1991–2014 at the Soroka University Medical Center, Beer-Sheva, Southern Israel. The mothers were subdivided into three groups, HBV carriers, HCV carriers and non-carriers. Data regarding the long-term endocrine morbidity of their offspring were compared between the groups. The study included 242,905 (99.7%) non-carrying mothers, 591 (0.2%) mothers who were carriers for HBV and 186 (0.1%) mothers who were carriers for HCV. The Kaplan–Meier’s survival curve demonstrated a significantly higher cumulative endocrine morbidity in children born to mothers with HCV (log-rank test, p = 0.002). Specifically, higher rates of hypoglycemia were noted among the offspring born to mothers who were carriers of HCV (1.1%; p = 0.001) compared with the offspring of mothers who were either carriers of HBV (0.2%) or non-carriers (0.1%). A Cox regression model controlled for maternal age, gestational age, maternal diabetes, hypertensive disorders of pregnancy, found maternal HCV carrier status to be independently associated with pediatric endocrine morbidity in the offspring (adjusted hazard ratio = 5.05, 95% CI: 1.625–15.695, p = 0.005). Maternal HCV carrier status is an independent risk factor for long-term endocrine morbidity.

Viral infections and risk of thyroid cancer: A systematic review and empirical bayesian meta-analysis

OBJECTIVE

The associations between viruses and the cancer have been conducted in several studies while there has been no systematic review and meta-analysis about the association between viral infections and thyroid cancer (TC). Therefore, we investigated the association between viral infection and TC risk.

METHODS

Systematic search was done from 1994 to 2019 in Web of sciences (ISI), PubMed, and Scopus databases. Pooled logarithm of odds ratio (OR) and their corresponding 95 % confidence interval (CI) and pooled prevalence of viral infections were calculated to find the association between the viral infections and TC risk and overall prevalence of the viral infections in TC.

RESULTS

Twenty-three of 852 original articles were selected and included in the study. According to the results of the random effect meta-analysis, the pooled prevalence of viral infections in the TC patients was 37 % (95 % C. I = 22 %-55 %). In addition, there was a significant association between viral infections (log (OR) = 1.51, 95 % credible interval = 0.68-2.39) and TC risk. The highest associations were observed between TC risk and Simian Vacuolating Virus 40 (SV40) and B19 infections, respectively. The lowest non-significant association was found between TC risk and Poliovirus type 1 infection. The significantly heterogeneity was observed between included studies (Q test: p-value<0.001; I² = 73.82 %; τ² = 1.08, 95 % Cr. I = 0.47-1.94).

CONCLUSIONS

Results clearly demonstrated the potential pathogenetic association between viral infections and increased risk of TC.

The aggregation between AITD with rheumatologic, or dermatologic, autoimmune diseases

Autoimmune thyroid diseases (AITD) are organ-specific autoimmune disorders mediated by Th1 lymphocytes, whose main clinical presentations are Hashimoto's thyroiditis (HT), or Graves' disease (GD). HT, GD, thyroid autoantibodies and thyroid dysfunctions have been shown in systemic rheumatologic diseases (as Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, or cryoglobulinemia). New associations of AITD with other autoimmune diseases are being discovered, for example with psoriatic arthritis and dermatological diseases. Several investigations suggest the importance of a shared genetic susceptibility and of environmental factors in patients with AITD and associated systemic autoimmunity. A major Th1 autoimmune response occurs in the initial, and/or active phases of organ-specific autoimmune disorders and/or systemic rheumatologic diseases with increased serum, or tissue, expressions of the Th1 chemokine CXCL10. Thyroid dysfunctions might have an important clinical impact, so a periodic thyroid screening in women with systemic or dermatological autoimmunity, overall in presence of thyroid autoantibodies is suggested.

Immunomodulation of CXCL10 Secretion by Hepatitis C Virus: Could CXCL10 Be a Prognostic Marker of Chronic Hepatitis C?

Chemokine (C-X-C motif) ligand (CXCL)10 and other CXCR3 chemokines are involved in the pathogenesis of acute and "chronic hepatitis C virus (HCV) infection" (CHC). Here, we review the scientific literature about HCV and CXCL10. The combination of circulating CXCL10 and single nucleotide polymorphisms (SNPs) in IL-28B can identify patients with acute HCV infection most likely to undergo spontaneous HCV clearance and those in need of early antiviral therapy. In CHC, the HCV and intrahepatic interferon- (IFN-) γ drive a raised CXCL10 expression by sinusoidal endothelium and hepatocytes, thereby inducing the recruitment of CXCR3-expressing T cells into the liver; thus, CXCL10 plays an important role in the development of necroinflammation and fibrosis. Increased CXCL10 was significantly associated with the presence of active vasculitis in HCV-associated cryoglobulinemia, or with autoimmune thyroiditis in CHC. Pretreatment CXCL10 levels are predictive of early virological response and sustained virological response (SVR) to IFN-α and ribavirin and may be useful in the evaluation of candidates for therapy. The occurrence of SNPs adjacent to IL-28B (rs12979860, rs12980275, and rs8099917), and CXCL10 below 150 pg/mL, independently predicted the first phase viral decline and rapid virological response, which in turn independently predicted SVR. Directly acting antiviral agents-mediated clearance of HCV is associated with the loss of intrahepatic immune activation by IFN-α, associated by decreased levels of CXCL10. In conclusion, CXCL10 is an important marker of HCV clearance and successful therapy in CHC patients. Whether CXCL10 is a novel therapeutic target in CHC will be evaluated.

Autoimmune and non-autoimmune thyroid dysfunction in HCV infected and HCV-HIV co-infected patients before and after interferon alpha therapy: A prospective study

INTRODUCTION

Autoimmune thyroid diseases are reported in no treated hepatitis C virus (HCV) infection. The standard interferon alpha (IFNα) treatment is associated with an increase of thyroid damage and dysfunction. The present cohort prospective study compared thyroid function and autoimmunity in HCV patients' monoinfected and coinfected HCV-HIV at baseline, during and after IFNα therapy.

METHODS

We studied 790 HCV infected patients: G1 (monoinfected HCV: N=580) and G2 (HCV-HIV coinfected: N=210). They were evaluated for thyroid function and thyroid tiroperoxidase antibodies (TPOAb) at baseline and 235 patients (G1: 183; G2: 52) post IFNα therapy. If thyroid dysfunction (TD) was diagnosed, they were reevaluated at 12 month after discontinuation to determine whether the TD was transitory or definitive.

RESULTS

No difference was found in the prevalence of TD at baseline in G1 (7.6%) and G2 (9%). However, monoinfected patients showed a higher prevalence of TPOAb positivity with a women preponderance in this group. There was no difference in TD between both groups during IFNα therapy (G1 23.5% vs G2 19.2%). In G1 the autoimmune TD was higher than in G2 (67.4% vs 30%, p=0.02). Autoimmune TD during IFNα tended to evolve to definitive hypothyroidism and non-autoimmune TD recovered euthyroidism after IFNα discontinuation. The presence of positive TPOAb (RR 3.55) and female gender (RR 2.4) were associated with the development of TD with IFNα therapy.

CONCLUSION

Our hypothesis is the importance of HCV in G1 and G2, combined with IFNα in triggering TD and TPOAb positivity, not described in other diseases' applications.

Depression and Insomnia Are Closely Associated with Thyroid Hormone Levels in Chronic Hepatitis B

Background

Depression and insomnia in chronic hepatitis B (CHB) patients affect the quality of life, disease diagnosis, and mortality. CHB patients are more likely to have psychological disorders, but the underlying mechanisms have not been elucidated. This study investigated the incidence of depression in patients with CHB and sought to identify risk factors for depression and insomnia in these patients, focusing on changes in liver function and thyroid hormone levels.

Material/Methods

This cross-sectional cohort study used the Hamilton Depression Scale and Athens Insomnia Scale to assess the depressive and insomnia states, respectively, of 209 CHB patients. Liver function, thyroid hormone levels, hepatitis B surface antigen, hepatitis B e-antigen, and hepatitis B virus-deoxyribonucleic acid load were evaluated. Liver cirrhosis was assessed by imaging (color Doppler ultrasound and computed tomography). A multivariate logistic regression model was used to analyze the correlation among various factors and depression and insomnia.

Results

Subclinical and clinical depressive states were found in 23.9% and 5.3% and subclinical and clinical insomnia in 11% and 35.4% of patients, respectively. Depression and insomnia severity were significantly correlated with low FT3 (<3.5 mol/L). The odds ratios of low FT3 for subclinical and clinical depression and clinical insomnia were 3.07 (95% confidence interval (CI), 1.248–7.568), 7.85 (95% CI, 1.839–33.547), and 3.91 (95% CI, 1.417–10.789), respectively.

Conclusions

CHB patients are prone to depression and insomnia. FT3 reduction may be a risk factor for depression and insomnia. In clinical settings, more attention needs to be paid to the mental state of patients with FT3 reduction.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Hepatitis C virus infection and development of type 2 diabetes mellitus: Systematic review and meta-analysis of the literature

Type 2 diabetes mellitus (T2DM) is an endocrine disorder encompassing multifactorial mechanisms, and chronic hepatitis C virus infection (CHC) is a multifaceted disorder, associated with extrahepatic manifestations, including endocrinological disorders. CHC and T2DM are associated, but the subject remains controversial. We performed a systematic review and meta-analysis evaluating such association, searching on PubMed until February 29, 2016. Inclusion criteria were: 1) presence of at least one internal control group age- and gender-matched (non-hepatopathic controls; and/or hepatopathic, not HCV-positive, controls); 2) sufficient data to calculate odds ratio and relative risk. Exclusion criteria were: 1) literature reviews on the topic; 2) publications regarding special populations [human immunodeficiency virus and human T-lymphotropic virus-1 coinfections, hepatocellular carcinoma (HCC), post-transplantation DM, gender selection]; 3) no clear differentiation among HCV patients with CHC, cirrhosis or HCC. Data from each study were independently extracted by two reviewers and cross-checked by AA. Our systematic review returned 544 records, and 33 were included in our meta-analysis. HCV infection is associated with an increased risk of T2DM independently from the severity of the associated liver disease, in CHC and cirrhotic HCV patients. As expected T2DM risk is higher in cirrhotic HCV patients, than CHC, and the prevalence of HCV infection in T2DM patients is higher than in non-diabetic controls. Regarding HBV infection prevalence, no difference exists in diabetic and non-diabetic subjects. An unequivocal CHC and T2DM association was shown. A proactive, integrated approach to HCV and T2DM therapies should maximize benefits of both diseases treatment.

[Chronic HCV infection: An internist's opinion (Part 2)]

Hepatitis C virus (HCV) infection results in not only chronic hepatitis and subsequent complications as liver cirrhosis and hepatocellular carcinoma, but also in a significant number of other diseases, the so-called extrahepatic manifestations of chronic HCV infection. In addition to lymphoproliferative and autoimmune disorders discussed in Part 1 of this review, many other diseases turned to be associated with chronic HCV infection. Part 2 of this review is dedicated to the analysis of the relationship of chronic HCV-infection to the development of some endocrine diseases, such as thyroiditis and diabetes mellitus, and cardiovascular disorders. It also provides the characteristics of the currently available antiviral agents and considers whether they may be used in patents with extrahepatic manifestations of chronic HCV infection.

Liver diseases and thyroid functional status

The liver is closely related to the thyroid function. On one hand, many liver diseases can cause abnormal thyroid function, such as hepatitis B virus (HBV) infection, hepatitis C virus (HCV) infection, liver cirrhosis, and nonalcoholic fatty liver disease. Thyroid dysfunction is also commonly caused by interferon alpha treatment for anti-HBV or HCV therapy. On the other hand, thyroid diseases such as hyperthyroidism or hypothyroidism can result in abnormal liver function. In addition, liver injury can also be frequently caused by antithyroid drugs or levothyroxine of over conventional doses. The causal relationship between abnormal liver function and thyroid dysfunction remains unclear.

Hepatitis C and Risk of Nonhepatic Malignancies

Epidemiologic studies show an increased risk of mortality among hepatitis C virus (HCV)-infected individuals compared with uninfected individuals from hepatic and nonhepatic causes. This article reviews the biologic plausibility of and epidemiologic evidence for the association between HCV and five extrahepatic malignancies: cholangiocarcinoma (CCA), pancreatic adenocarcinoma, papillary thyroid cancer, oral squamous cell cancer, and renal/kidney cancer. There is sufficient evidence to suggest that HCV is associated with intrahepatic CCA. The evidence for the link between HCV and pancreatic adenocarcinoma, oral squamous cell cancer, and renal/kidney cancer is compelling but requires further study. Based on available studies, there is no significant association between HCV, extrahepatic CCA, and papillary thyroid cancer.

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.

Relapse prediction in Graves´ disease: Towards mathematical modeling of clinical, immune and genetic markers

PROBLEM

Graves' disease (GD) is an important and prevalent thyroid autoimmune disorder. Standard therapy for GD consists of antithyroid drugs (ATD) with treatment periods of around 12 months but relapse is frequent. Since predictors for relapse are difficult to identify the individual decision making for optimal treatment is often arbitrary.

METHODS

After reviewing the literature on this topic we summarize important factors involved in GD and with respect to their potential for relapse prediction from markers before and after treatment. This information was used to design a mathematical model integrating thyroid hormone parameters, thyroid size, antibody titers and a complex algorithm encompassing genetic predisposition, environmental exposures and current immune activity in order to arrive at a prognostic index for relapse risk after treatment.

CONCLUSION

In the search for a tool to analyze and predict relapse in GD mathematical modeling is a promising approach. In analogy to mathematical modeling approaches in other diseases such as viral infections, we developed a differential equation model on the basis of published clinical trials in patients with GD. Although our model needs further evaluation to be applicable in a clinical context, it provides a perspective for an important contribution to a final statistical prediction model.

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

Background:

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

Aim:

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

Materials and Methods:

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

Results:

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

Conclusion:

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

Hepatitis C virus and neurological damage

Chronic hepatitis C virus (HCV) infection exhibits a wide range of extrahepatic complications, affecting various organs in the human body. Numerous HCV patients suffer neurological manifestations, ranging from cognitive impairment to peripheral neuropathy. Overexpression of the host immune response leads to the production of immune complexes, cryoglobulins, as well as autoantibodies, which is a major pathogenic mechanism responsible for nervous system dysfunction. Alternatively circulating inflammatory cytokines and chemokines and HCV replication in neurons is another factor that severely affects the nervous system. Furthermore, HCV infection causes both sensory and motor peripheral neuropathy in the mixed cryoglobulinemia as well as known as an important risk aspect for stroke. These extrahepatic manifestations are the reason behind underlying hepatic encephalopathy and chronic liver disease. The brain is an apt location for HCV replication, where the HCV virus may directly wield neurotoxicity. Other mechanisms that takes place by chronic HCV infection due the pathogenesis of neuropsychiatric disorders includes derangement of metabolic pathways of infected cells, autoimmune disorders, systemic or cerebral inflammation and alterations in neurotransmitter circuits. HCV and its pathogenic role is suggested by enhancement of psychiatric and neurological symptoms in patients attaining a sustained virologic response followed by treatment with interferon; however, further studies are required to fully assess the impact of HCV infection and its specific antiviral targets associated with neuropsychiatric disorders.

Novel Therapies for Thyroid Autoimmune Diseases

C-X-C chemokine receptor (CXCR)3 and its interferon(IFN)γ-dependent chemokines (CXCL10, CXCL9, CXCL11) are implicated in the immune-pathogenesis of autoimmune thyroiditis (AT), Graves disease (GD) and Graves Ophthalmopathy (GO). In tissue, recruited Th1 lymphocytes produce IFNγ, enhancing the tissue secretion of IFNγ-inducible chemokines, initiating and perpetuating the autoimmune process. Patients with AT (with hypothyroidism), and with GO and GD, particularly in the active phase, have high IFNγ-inducible chemokines. Peroxisome proliferator-activated receptor (PPAR)γ or -α agonists and methimazole exert an immune-modulation on CXCR3 chemokines in AT, GD and GO. Other studies are ongoing to evaluate new molecules acting as antagonists of CXCR3, or blocking CXCL10, in Hashimoto thyroiditis (HT), GD and GO. Recently, novel molecules targeting the various agents involved in the pathogenesis of GO, such as rituximab, have been proposed as an alternative to corticosteroids. However, randomized and controlled studies are needed to generalize these interesting results.

Thyroid function is associated with non-alcoholic fatty liver disease in chronic hepatitis B-infected subjects

BACKGROUND AND AIMS

Associations between thyroid function and non-alcoholic fatty liver disease (NAFLD) are unknown in chronic hepatitis B (CHB)-infected patients. Thus, the aim of the study was to investigate the prevalence of thyroid dysfunction and its relationship with NAFLD in CHB.

METHODS

Consecutive naive CHB infected patients that had undergone liver biopsy and serum thyroid function tests between January 2007 and December 2011 were retrospective analyzed. NAFLD was diagnosed as at least 5% biopsy-proven hepatic steatosis without significant alcohol consumption.

RESULTS

A total of 1154 non-alcoholics with CHB were included, 270 (23.39%) patients were found to have NAFLD, most of them (88.5%) with mild steatosis. The prevalence of hyperthyroidism and hypothyroidism (including subclinical and overt) was 1.56% and 1.64%, respectively, both with similar rates in patients with and without NAFLD (1.85% vs 1.47%, 1.48% vs 1.69%, respectively, both P > 0.05). The serum thyroid-stimulating hormone (TSH) level in NAFLD patients was significantly higher than that in patients without NAFLD (2.22 ± 2.13 vs 1.61 ± 1.20 mIU/L, P < 0.05). After adjustment for age and gender, the elevated TSH level was associated with increased odds of having steatosis (odds ratio1.54, 95% confidence interval 1.049-2.271) instead of viral factors and hepatic inflammation and fibrosis.

CONCLUSIONS

Thyroid dysfunction is not common in CHB-infected patients, and the prevalence of hypothyroidism in CHB individuals with or without NAFLD is similar. However, increased serum TSH concentration at the normal range is a significant predictor of hepatic steatosis in patients with CHB.

Incidence of and risk factors for thyroid dysfunction during peginterferon α and ribavirin treatment in patients with chronic hepatitis C

BACKGROUND/AIMS

Thyroid dysfunction (TD) is more likely to occur in patients with chronic hepatitis C (CHC) and is particularly associated with interferon (IFN) treatment. The purpose of this study was to investigate the incidence, outcomes, and risk factors for TD during pegylated interferon (PEG-IFN) and ribavirin (RBV) combined therapy in patients with CHC.

METHODS

A total of 242 euthyroid patients with CHC treated with PEG-IFN/RBV were included. Thyroid function and autoantibodies were measured at baseline, and virologic response and thyroid function were assessed every 3 months during therapy.

RESULTS

TD developed in 67 patients (27.7%) during the PEG-IFN/RBV treatment. The types of TD were subclinical hypothyroidism (50.7%), hypothyroidism (14.9%), thyroiditis (11.9%), subclinical hyperthyroidism (10.4%), and hyperthyroidism (10.4%). Most of the patients with TD recovered spontaneously; however, seven patients (10.4%) needed thyroid treatment. The sustained virological response rate was higher in patients with TD than those without (65.7% vs. 49.1%, p = 0.02). Baseline thyroid stimulating hormone (TSH) concentrations (odds ratio [OR], 2.09; 95% confidence interval [CI], 1.96 to 8.77; p < 0.001), presence of the thyroid peroxidase antibody (OR, 8.81; 95% CI, 1.74 to 44.6; p = 0.009), and PEG-IFNα-2b (OR, 3.01; 95% CI, 1.43 to 6.39; p = 0.004) were independent risk factors for the development of TD.

CONCLUSIONS

TD developed in 27.7% of patients with CHC during PEG-IFN/RBV treatment, and 10.4% of these patients needed thyroid treatment. TD is associated with a favorable virologic response to PEG-IFN/RBV. Assessment of TSH and thyroid autoantibodies at baseline and close monitoring of thyroid function during PEG-IFN/RBV therapy are necessary for early detection and management of IFN-induced TD.

A biopsychosocial approach to primary hypothyroidism: treatment and harms data from a randomized controlled trial

BACKGROUND

Hypothyroidism is a common endocrine condition. There is evidence to suggest that, for a proportion of sufferers, the standard medical treatment does not completely reverse the constitutional and neuropsychiatric symptoms brought about by this condition. The management of hypothyroidism follows a biomedical model with little consideration given to alternative management approaches. There exists anecdotal evidence and case reports supporting the use of a biopsychosocial-based intervention called Neuro-Emotional Technique (NET) for this population. The aim of this study was to explore the potential short-medium term clinical efficacy and safety of NET for individuals with primary hypothyroidism.DesignPlacebo-controlled, blinded, parallel groups, randomized trial.

METHODS

Ninety adults with a diagnosis of primary hypothyroidism were recruited from Sydney, Australia. Blinded participants were randomized to either the NET or placebo group and received ten intervention sessions over a six week period. The primary outcome involved the measurement of states of depression using the DASS-42 questionnaire. Secondary outcomes included thyroid function, thyroid autoimmunity testing, SF-36v2 questionnaire, resting heart rate and temperature measurement. Outcomes were obtained at baseline, seven weeks and six months. Questionnaires were completed at the private clinics, and serum measures were obtained and analysed at commercial pathology company locations. Heart rate and temperature were also measured daily by participants. Linear mixed-effects models were used to analyse the continuous outcomes. Unadjusted odds ratios with 95% confidence intervals were calculated for the binary outcomes.

RESULTS

Participants were randomly allocated to the NET (n=44) and placebo (n=46) groups. A proportion of the sample displayed neuropsychiatric disturbances and alterations in quality of life measures at baseline. There were no statistically significant or clinically relevant changes in the primary or secondary outcomes between the NET and placebo groups at time seven weeks or six months. There were a few short-lived minor adverse events reported in both the NET and placebo groups that coincided with the application of the intervention.

CONCLUSIONS

The application of the NET intervention appears to be safe, but did not confer any clinical benefit to the participants in this study and is unlikely to be of therapeutic use in a hypothyroid population.

CLINICAL TRIALS REGISTRATION NUMBER

Australian and New Zealand Clinical Trials Registry Number: 12607000040460.

Cytokines and HCV-related autoimmune disorders

Cytokines are intercellular mediators involved in viral control and liver damage being induced by infection with hepatitis C virus (HCV). The complex cytokine network operating during initial infection allows a coordinated, effective development of both innate and adaptive immune responses. However, HCV interferes with cytokines at various levels and escapes immune response by inducing a T-helper (Th)2/T cytotoxic 2 cytokine profile. Inability to control infection leads to the recruitment of inflammatory infiltrates into the liver parenchyma by interferon (IFN)-γ-inducible CXC chemokine ligand (CXCL)9, -10, and -11 chemokines, which results in sustained liver damage and eventually in liver cirrhosis. The most important systemic HCV-related extrahepatic diseases-mixed cryoglobulinemia, lymphoproliferative disorders, thyroid autoimmune disorders, and type 2 diabetes-are associated with a complex dysregulation of the cytokine/chemokine network, involving proinflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-α may result in viral clearance during persistent infection and revert this process. Theoretically agents that selectively neutralize CXCL10 could increase patient responsiveness to traditional IFN-based HCV therapy. Several studies have reported IL-28B polymorphisms and circulating CXCL10 may be a prognostic markers for HCV treatment efficacy in HCV genotype 1 infection.

THE ABSENCE OF THYROID DISEASE IN AN AUSTRALIAN HEPATITIS C COHORT TREATED WITH TRIPLE COMBINATION THERAPY: A PARADIGM SHIFT

OBJECTIVE

To assess the prevalence of thyroid disease in triple combination therapy with interferon (IFN)-α, ribavirin (RBV), and protease inhibitors (boceprevir and telaprevir) for the treatment of chronic hepatitis C virus (HCV) infection in an Australian hepatitis C cohort. Also, to compare with those who received dual RBV and IFN in the past.

METHODS

A preliminary, retrospective, and nested case control study of thyroid disease in patients who underwent triple combination therapy for chronic HCV infection compared with dual therapy at a major tertiary referral hospital center. Fifty-nine patients were treated with such therapy at the Hunter New England Area Hepatitis C Treatment Center. Of these, 38 were treated with boceprevir and 21 with telaprevir. All had genotype 1 HCV infection. The main outcome measures included (1) the prevalence of thyroid disease (TD), including hyperthyroidism and hypothyroidism, and (2) thyroid outcome comparison with patients who had received dual therapy.

RESULTS

There was no case of TD detected for the entire duration of therapy with triple anti-HCV therapy. There was a significant absence of TD in the protease inhibitor-treated group.

CONCLUSION

No case of TD was detected during the treatment of HCV patients with protease inhibitor-based triple therapy. The reasons for this are unclear. Larger studies are necessary to confirm this finding.

Autoantibodies in chronic hepatitis C: A clinical perspective

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

Autoimmune thyroid disorders

Autoimmune thyroid diseases (AITD) result from a dysregulation of the immune system leading to an immune attack on the thyroid. AITD are T cell-mediated organ-specific autoimmune disorders. The prevalence of AITD is estimated to be 5%; however, the prevalence of antithyroid antibodies may be even higher. The AITD comprise two main clinical presentations: Graves' disease (GD) and Hashimoto's thyroiditis (HT), both characterized by lymphocytic infiltration of the thyroid parenchyma. The clinical hallmarks of GD and HT are thyrotoxicosis and hypothyroidism, respectively. The mechanisms that trigger the autoimmune attack to the thyroid are still under investigation. Epidemiological data suggest an interaction among genetic susceptibility and environmental triggers as the key factor leading to the breakdown of tolerance and the development of disease. Recent studies have shown the importance of cytokines and chemokines in the pathogenesis of AT and GD. In thyroid tissue, recruited T helper 1 (Th1) lymphocytes may be responsible for enhanced IFN-γ and TNF-α production, which in turn stimulates CXCL10 (the prototype of the IFN-γ-inducible Th1 chemokines) secretion from the thyroid cells, therefore creating an amplification feedback loop, initiating and perpetuating the autoimmune process. Associations exist between AITD and other organ specific (polyglandular autoimmune syndromes), or systemic autoimmune disorders (Sjögren's syndrome, rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, cryoglobulinemia, sarcoidosis, psoriatic arthritis). Moreover, several studies have shown an association of AITD and papillary thyroid cancer. These data suggest that AITD patients should be accurately monitored for thyroid dysfunctions, the appearance of thyroid nodules, and other autoimmune disorders.

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

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

Autoimmune and neoplastic thyroid diseases associated with hepatitis C chronic infection

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

Thyroid involvement in hepatitis C - associated mixed cryoglobulinemia

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Immunological alterations in hepatitis C virus infection

A higher prevalence of immunological processes has recently been reported in patients with hepatitis C virus (HCV) infection, focusing the attention of physicians and researchers on the close association between HCV and immune disorders. HCV lymphotropism represents the most important step in the pathogenesis of virus-related immunological diseases and experimental, virologic, and clinical evidence has demonstrated a trigger role for HCV both in systemic autoimmune diseases, such as rheumatoid arthritis, Sjögren syndrome, hemolytic anemia and severe thrombocytopenia, and in organ-specific autoimmune diseases, such as autoimmune hepatitis, thyroid disorders and diabetes. This review will outline the principal aspects of such HCV-induced immunological alterations, focusing on the prevalence of these less characterized HCV extrahepatic manifestations.

Associations of Helicobacter pylori infection and cytotoxin-associated gene A status with autoimmune thyroid diseases: a meta-analysis

BACKGROUND

Helicobacter pylori infection is reportedly associated with extradigestive diseases such as immune thrombocytopenic purpura and coronary heart disease. The risk factors for autoimmune thyroid diseases (ATDs) remain largely unknown, and whether H. pylori infection is associated with ATDs is still controversial. The aim of this meta-analysis was to determine the association between H. pylori infection and ATDs.

METHODS

Studies comparing the prevalence rate of H. pylori infection in patients with ATDs and healthy controls, published in English, were identified through a systematic search in MEDLINE and EMBAS up to June 2012. Serological or nonserological tests were used to confirm H. pylori infection and the presence of cytotoxin-associated gene A (CagA) antigens. The odds ratios (OR) and associated 95% confidence intervals [CI] were obtained.

RESULTS

Seven studies involving a total of 862 patients met the inclusion criteria and thus were included in our meta-analysis. Overall, H. pylori infection was associated with ATDs (OR 1.92 [CI 1.41-2.61]); the association was significant for Graves' disease (OR 4.35 [CI 2.48-7.64]) but not for Hashimoto's thyroiditis (OR 1.45 [CI 0.92-2.26], p=0.11). No association was observed in the subanalysis of studies using only enzyme-linked immunosorbent assay to detect H. pylori infection (OR 1.38 [CI 0.86-2.19], p=0.18). Five of the seven articles reported the association of CagA seroprevalence and ATDs. CagA seropositivity significantly increased the risk for ATDs by 2.24-fold [CI 1.06-4.75].

CONCLUSIONS

Both the prevalence of H. pylori infection and the seroprevalence of CagA-positive strains are associated with ATDs. These findings suggest that H. pylori infection potentially plays a part in the development of ATDs.

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.

The presence of thyroid peroxidase antibody of IgG2 subclass is a risk factor for thyroid dysfunction in chronic hepatitis C patients

OBJECTIVE

To investigate the prevalence of thyroid dysfunction (TD) and IgG subclasses of thyroid autoantibodies (TAs) and to determine the predictive factors of TD in chronic hepatitis C (CHC) patients.

DESIGN

Three hundred and twelve untreated hepatitis C virus-infected patients without a history of TD or treatment with thyroid hormones were enrolled in a cross-sectional study. Clinical and biological factors were statistically analyzed to determine the correlation between TD and this patient population.

RESULTS

The incidence of TD WAS 12.5% in CHC patients. Clinical hypothyroidism (5.8%) and subclinical hypothyroidism (3.8%) were more frequent than clinical hyperthyroidism (1.6%) and subclinical hyperthyroidism (1.3%). The percentage of TA-positive patients was significantly higher in people 60 years than in those 60 years (31.9 VS 18.6%; P=0.042). Positive thyroid peroxidase antibody (TPOAb) was more frequent, and alanine aminotransferase (ALT) levels were lower in patients who displayed TD (TPOAb: 62.1 vs 10.8%, P=0.000; ALT: 43.5 vs 51 IU/l, P=0.046). The positive percentage of TPOAb IgG2 subclass in the TD group was significantly higher than that of patients without TD (66.7 vs 16.7%, P=0.005). Multiple logistic regression analysis indicated that only TPOAb IgG2 subclass positivity was an independent risk factor for TD in CHC patients (odds ratio=8; 95% CI: 1.225-52.246; P=0.030).

CONCLUSIONS

TPOAb IgG2 subclass positivity is a risk factor for TD in CHC patients before antiviral treatment. IgG2 subclass of TPOAb might play an important role in the presence of TD in CHC patients.

A nationwide seroepidemiology of hepatitis C virus infection in South Korea

BACKGROUND & AIMS

The aim of this study was to reveal nationwide seroprevalence of HCV infection in South Korea by a large-scale survey.

METHODS

From January to December 2009, a total of 291 314 adults underwent health check-up in 29 centres nationwide. The data concerning anti-HCV antibody and biochemical tests were obtained from all participants. Among subjects with positive anti-HCV, such data as HCV RNA, genotypes and treatment detail were additionally analysed.

RESULTS

Using an estimated 2009 population of Korea, the age, sex and area-adjusted anti-HCV positive rate was 0.78%. Anti-HCV prevalence in female patients (0.83%) was higher than that in male patients (0.75%). Gradual increase in anti-HCV positivity was observed, from 0.34% in those aged 20-29 years to 2.31% in those >70 years. The age- and sex-adjusted anti-HCV prevalence varied in different areas, being higher in Busan and Jeonnam (1.53-2.07%), mid-level in Seoul and surrounding districts (0.50-0.61%) and lower in Jeju (0.23%). The comparative analysis of laboratory variables between anti-HCV (+) and anti-HCV (-) group revealed significantly higher levels of alanine aminotransferase and lower levels of serum lipids in anti-HCV (+) group. Among 1 718 anti-HCV positive subjects, serum HCV RNA was measured only in 478 people, of whom 268 (56.1%) patients had detectable HCV RNA in serum. Among 50 patients for whom assessment of response to antiviral therapy was feasible, overall sustained virological response was achieved in 84% of patients.

CONCLUSION

The prevalence of HCV infection is low in South Korea. Studies to analyse risk factors are warranted to reduce HCV infection.