22 research outputs found

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

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    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

    The hypothalamic-pituitary-thyroid axis in subjects with subclinical thyroid diseases: The impact of the negative feedback mechanism

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    Objective: To evaluate the hypothalamus-pituitary-thyroid (HPT) axis in patients with subclinical thyroid dysfunction recently reported to have either symptoms or organ involvements with potential morbidity, in order to better differentiate these patients with respect to controls. Patients: Sixtythree patients with subclinical hyperthyroidism (HyperT), 178 normal subjects (EuT) and 106 patients with subclinical hypothyroidism (HypoT) were enrolled; the groups presented normal thyroid hormone (FT4, FT3) levels and, respectively, reduced (HyperT), normal (EuT) and increased (HypoT) TSH levels. The negative feedback was simultaneously evaluated by multiple linear regression. Results: The mean TSH, FT4 and FT3 levels were significantly different in the three groups. The negative correlation between thyroid hormones (FT4 and FT3) and TSH secretion was significant (p<0.001 in HyperT; p<0.01 in EuT; p<0.000001 in HypoT group). FT4 mostly contributed to the negative correlation with TSH. The normal ranges of TSH values was accurately defined on the basis of the regression equation in the EuT group, due to the combining influence of both thyroid hormones (FT3 and FT4). No patient of the HyperT or HypoT group fell inside the range of estimated values of the normal group. Conclusions: The HPT axis in patients with subclinical hyper- and hypo-thyroidism is significantly modified with respect to normal subjects. The status of the axis, as evaluated by the relationship between the three hormones (FT4, FT3, TSH) together considered, is characteristic of the normal or pathologic condition. A reliable method based on the regression analysis is proposed to correctly evaluate the status of the HPT axis. Copyright © Neuroendocrinology Letters

    Association between human leukocyte antigen (HLA) and interferon- induced thyroid diseases in four patients with HCV-related chronic hepatitis.

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    The interferon-alpha (IFN-alpha) therapy for HCV hepatitis may exacerbate or induce underlying thyroid disorders. Besides viral factors, the human leukocyte antigen (HLA) may be an independent risk factor. We evaluated fifteen patients with HCV chronic hepatitis during a period of 40 months. At the enrollment, all the patients were negative for thyroid disorders, excluding one patient with subclinical hypothyroidism. Eleven patients received IFN-alpha therapy. The HLA system was examined in every patient, evaluating antigens (n=40) of locus A, B and Cw and alleles (n=19) of locus DRB1* and DQB1*. The HLA system was also examined in healthy subjects (n=107) as a control group. The HCV genotype distribution in patients was: 1b=20%, 2a=60%, 3a=20%. Four IFN-treated patients presented clinical thyroid disorders, including autoimmune hypothyroidism (n=2), transient thyrotoxicosis (n=1) and subacute thyroiditis (n=1). The HLA susceptibility to thyroid disorders (antigen/allele frequency) in the whole group of patients was not different in respect to controls and normal Italian population. The patients with HCV chronic hepatitis that developed thyroid diseases after IFN- treatment had a double and specific association with the HLA system (Mantel-Haenszel X(c)(2)=4.706, p<0.05). This case report suggests that HLA system examination is an important and promising diagnostic aspect that may be considered in order to evaluate the appearance of thyroid disorders during the IFN-alpha treatment for HCV-related chronic hepatitis
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