[Hepatitis C virus infection and thyroid diseases]

HCV Extrahepatic Manifestations

Hepatitis C virus (HCV) has been shown to affect many tissues other than liver. However, of the many extrahepatic manifestations (EMs) that have been associated with HCV, including cryoglobulinemia, lymphoma, insulin resistance, type 2 diabetes and neurological disorders, only a few have been shown to be directly related to HCV infection of extrahepatic tissues. HCV-triggered immune-mediated mechanisms account for most of the EMs. It is estimated that up to 74% of patients with chronic hepatitis C can develop at least one EM. All HCV patients with EMs should be considered for antiviral therapy, although not all will resolve with sustained virological response.

Hepatitis C virus as a systemic disease: reaching beyond the liver

Chronic hepatitis C (CHC) is associated with multiple extrahepatic manifestations that may impact infected patients. The mechanisms through which these develop include those which are immunological, in which the chronic persistence of virus leads to the circulation of immune complexes (mixed cryoglobulinemia) and other autoimmune phenomena, and those which are virological and related to the extrahepatic tropism of the virus to other tissues. It is estimated that 40-74 % of patients with CHC may develop at least one extrahepatic manifestation during the course of the disease. Extrahepatic syndromes may represent the first signal of hepatitis C infection in some patients. CHC is associated with a four-fold increased risk of insulin resistance and type 2 diabetes mellitus; with cardiovascular disease in 17-37 % of patients; and with increased risk for cerebrovascular deaths, with a biological gradient of cerebrovascular mortality correlating with an increasing serum viral load. CHC is also associated with lymphoproliferative disorders, particularly non-Hodgkin B-cell lymphoma. The kidney is involved in 35-60 % of patients with CHC-associated mixed cryoglobulinemia. The prevalent type of glomerulonephritis associated with mixed cryoglobulinemia is membranoproliferative glomerulonephritis. In 30 % of cases, renal involvement begins with a nephritis syndrome and acute renal failure, while in 55 % there is only mild hematuria, microalbuminuria, proteinuria and renal insufficiency. CHC is also associated with cognitive impairment, especially in memory and concentration. Thus, extrahepatic CHC manifestations involve multiple organ systems outside the liver linked to a variety of comorbidities which may lead to significantly increased mortality from non-liver-related events.

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

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

[Thyroid in the elderly (Part 1)]

Aging is associated with changes in thyroid function at several levels of regulation. Thyroid hormones levels are usually within the lower part of normal values reported in the general population. Two changes in aging are of clinical importance: a shift in the distribution of TSH levels, the 97.5th percentile of the TSH distribution being within 6 μUI/ml after 70 years and within 7.5 μUI/ml in subjects older than 80 instead of 4.5 μU/ml in the general population, and an increased prevalence of thyroid nodularity, requiring reliable and non-invasive methods of investigation in older people. Lastly, aging may be associated with comorbidities, high risk of drug interactions and under nutrition, which may make difficult the interpretation of laboratory data and in some cases induce iatrogenic thyroid diseases. Considering the high prevalence of the thyroid diseases in older patients and a better understanding of the physiopathological hormonal variations with the ageing, it seemed useful to propose a review to help the clinician in the care of these situations.

[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.

Hypothyroidism in Noninterferon Treated-HCV Infected Individuals Is Associated with Abnormalities in the Regulation of Th17 Cells

HCV-Ag-specific TH17 cells secrete IL17, a cytokine involved in autoimmune diseases and regulated by IL10 and TGF-b. 5–12% of patients with chronic HCV infection have hypothyroidism. We evaluated the role of these cytokines in this patients by determining serum concentration of TsH, T3, free T4, IL2, IL10, IL12, IL17, TGF-b, anti-TG, TPO, CCP, GBM, and cardiolipin antibodies in 87 chronically noninterferon treated HCV-infected patients. 20 patients (group A) had elevated TsH values (>5 μUI/ml) whereas the remaining 67 (group B) had normal values. The percentage of anti-TPO, TG, GBM, and cardiolipin antibodies in group A patients (33%, 41%, 5% and 5%, resp.) as well as IL17, IL2 and TGF-b concentrations (25 ± 23 pg/ml, 643 ± 572 pg/ml, and 618 ± 221 pg/ml, resp.) were significantly higher than group B. Abnormal Th17 regulation mediated by IL-2 and low TGF-b concentrations is associated with hypothyroidism in chronically-infected HCV patients.

Evolution and predictive factors of thyroid disorder due to interferon alpha in the treatment of hepatitis C

AIM: To study predictive factors of thyroid dysfunction associated with interferon-alpha (IFNα) therapy in chronic hepatitis C (CHC) and to describe its long-term evolution in a large population without previous thyroid dysfunction.

METHODS: We performed a follow-up of thyroid function and detection of thyroid antibodies in 301 patients treated for CHC with IFNα from 1999 to 2004.

RESULTS: Thyroid disorder developed in 30/301 (10%) patients with a mean delay of 6 ± 3.75 mo: 13 patients had hyperthyroidism, 11 had hypothyroidism, and 6 had biphasic evolution. During a mean follow-up of 41.59 ± 15.39 mo, 9 patients with hyperthyroidism, 3 with hypothyroidism, and 4 with biphasic evolution normalized thyroid function in 7.88 ± 5.46 mo. Recovery rate of dysthyroidism was not modified by treatment discontinuation, but was better for patients with negative thyroid antibodies before antiviral treatment (P = 0.02). Women had significantly more dysthyroidism (P = 0.05). Positive thyroid peroxidase and thyroglobulin antibodies were more frequent before antiviral treatment in patients who developed dysthyroidism (P < 0.0003 and P = 0.0003, respectively). In a multivariate model, low fibrosis was found to be a predictive factor of dysthyroidism (P = 0.039).

CONCLUSION: In this monocentric population of CHC, dysthyroidism, especially hyperthyroidism, developed in 10% of patients. Low fibrosis was found to be a predictive factor of dysthyroidism. Thyroid disorder recovered in 16/30 patients (53%) and recovery was better in the non-autoimmune form.

Peginterferon Alpha/Ribavirin Combination Therapy for the Treatment of Hepatitis C Infection

Chronic infection with the hepatitis C virus is widespread in the United States. This disease is associated with a progression of fibrosis of the liver leading to liver cirrhosis in as many as 20% of cases. The current standard of care for the treatment of chronic hepatitis C infection is combination therapy with pegylated interferon alpha plus ribavirin. In more than 50% of patients, this regimen has been shown to induce a sustained viral response, defined as undetectable hepatitis C viral ribonucleic acid (RNA) for 6 months after the end of treatment. Typically, patients are treated for 24 or 48 weeks. A number of possible adverse events are associated with combination therapy, and patient empowerment through supportive nursing care is critical to facilitating patient adherence to treatment. This article provides an update on information concerning the diagnosis and treatment of chronic hepatitis C infection. This information can be tailored to provide patient-focused assessment, education, and treatment.

Risk factors and long-term course of thyroid dysfunction during antiviral treatments in 221 patients with chronic hepatitis C

AIM

To identify the predictive factors of dysthyroidism during treatment for chronic viral hepatitis C and to evaluate the long-term outcome of these patients.

METHODS

Patients treated for chronic viral hepatitis C between 1990 and 2001 were analyzed retrospectively. Patients with dysthyroidism before treatment and patients positive for hepatitis B surface antigen or human immunodeficiency virus antibodies were excluded. Dysthyroidism was defined by an abnormal serum TSH level on two separate occasions.

RESULTS

221 consecutive patients were included. Among them, a hundred were treated twice by interferon alpha, 21 had 3 treatments and 3 had 4 treatments. Fifteen of these patients (7%) had dysthyroidism during antiviral therapy. There was no significant difference in the frequency of dysthyroidism during the first and the second treatment [respectively 4,1% (N = 9) and 6% (N = 6)]. Female gender and the presence of antimicrosome or antithyroperoxydase (anti-TPO) antibodies before antiviral treatment were predictive factors of dysthyroidism. Treatment by interferon and ribavirin did not increase the risk of dysthyroidism compared to monotherapy with interferon. Pegylated interferon (N = 49) was not a risk factor compared to standard interferon. Thirteen patients had hypothyroidism (2 of them as a result of biphasic thyroiditis) and 2 had hyperthyroidism. The antiviral treatment was continued in 11 patients. Seven out of 13 patients with hypothyroidism required an indefinite treatment (follow-up: 15 to 90 months).

CONCLUSIONS

In our series, 7% of patients with chronic viral hepatitis C had a dysthyroidism during antiviral therapy. Predictive factors were female gender and positive antimicrosome or anti-TPO antibodies before treatment. Absence of dysthyroidism during a first antiviral treatment did not preclude from the risk of dysthyroidism during a second treatment.