HCV genotype 6 is restricted in its distribution in South East Asia and it has been circulating for a long period of time. Phylogenetic and phylodynamic analysis on epidemic history of HCV focusing genotype 6 in South East Asia was explored, taking references from the pattern delineated in Liuzhou. Our results show that the date of most recent common ancestor (MRCA) of the whole HCV genotype 6 was estimated to be 100 years ago or more. There was an obvious increase of effective number of HCV genotype 6 infections in the part 20 years. Epidemic history of Subtype 6a and 6e/6d also showed the similar time course as that of the genotype 6. Interestingly, there was an increase of effective number of infections around 15-20 years ago which was maintained in the following decade for subtype 6a as well as 6e/6d. This specific pattern was consistent with the history of needle sharing in South East Asia, where the number of IDUs increased in the 1980s. The epidemic then spread to Southern China as evident by the increasing trend in Liuzhou. There was an exponential growth around 5 years ago involving subtype 6a predominantly, which might remain prevalent in Southern China in the coming decades. In conclusion, the study has shed new light on the transmission history of HCV, providing an explanation on the emergence of HCV genotype 6 in South East Asia. / HCV infection is an important public health problem associated with blood transfusion and needle-sharing in injection drug users (IDU) in Southern China. An understanding of the epidemiological pattern of the HCV infection, in conjunction with the transmission dynamics, would be beneficial for supporting effective prevention and control. This is accessed using a combination of molecular and public health approaches. / Through the Liuzhou Methadone Clinic, a total of 117 IDUs were recruited from Guangxi, Southern China. A majority of the IDUs (96%) were HCV antibody positive, of which 21% were HIV infected. Unlike HCV monoinfection, there was spatial heterogeneity in the distribution of HIV/HCV coinfection. The latter was also characterised by a higher prevalence of needle-sharing. Phylogenetic analysis of HCV revealed that genotype 6a was predominant in the study population. There were shorter genetic distances among the 6a samples compared to 3 other HCV genotypes/subtypes, 1a, 3a, and 3b. Our results suggested that HIV and HCV were both introduced at around the same time to the IDU populations in Southern China, followed by their differential spread as determined by the biologie characteristics of the virus and the intensity of behavioural risk. This pattern might be different from that in other South East Asian countries where HCV infections have probably predated HIV. / Tan, Yi. / Adviser: Kung Hsiang-fu. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3404. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 164-178). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Submitted by LUISA FOURNIER ARAUJO null (luhfournier@yahoo.com.br) on 2017-03-13T15:05:59Z No. of bitstreams: 1 DISSERTACAO LUISA FOURNIER.pdf: 1448990 bytes, checksum: 2f1266701041a2c76dd899bf05730b15 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-03-20T13:02:31Z (GMT) No. of bitstreams: 1 araujo_lf_me_bot.pdf: 1448990 bytes, checksum: 2f1266701041a2c76dd899bf05730b15 (MD5) / Made available in DSpace on 2017-03-20T13:02:31Z (GMT). No. of bitstreams: 1 araujo_lf_me_bot.pdf: 1448990 bytes, checksum: 2f1266701041a2c76dd899bf05730b15 (MD5) Previous issue date: 2017-02-22 / A hepatite C crônica é uma doença causada pelo vírus da hepatite C e que cursa com inflamação hepática crônica, podendo levar à cirrose, insuficiência hepática terminal e carcinoma hepatocelular. O tratamento tem o objetivo de inibir permanentemente a replicação viral, porém quando se utiliza interferon peguilado e ribavirina alguns efeitos colaterais são comuns, como a perda de peso, que pode levar à interrupção do tratamento. A hipótese do estudo foi que o grau de fibrose e as doses de ribavirina pudessem influenciar a perda de peso e de outras medidas antropométricas durante o tratamento antiviral. O objetivo foi verificar a relação entre o grau de acometimento hepático, a idade, o sexo, a dose de ribavirina e a perda de medidas antropométricas em pacientes com hepatite C crônica em tratamento com interferon peguilado e ribavirina. Participaram do estudo 76 pacientes ambulatoriais avaliados por mensuração de peso, altura, dobra cutânea triciptal, circunferência do braço, circunferência muscular do braço e área muscular do braço, medidos antes e depois de 24 semanas de tratamento. Dados epidemiológicos foram obtidos do prontuário dos pacientes, analisando também resultados de biópsia hepática. Inicialmente a amostra foi dividida em dois grupos de acordo com a presença ou não de fibrose hepática avançada, sendo então realizada comparação entre valores observados em cada grupo ao longo do tratamento, utilizando o teste t pareado ou o teste de Wilcoxon. A seguir as alterações antropométricas ao longo do tratamento antiviral foram avaliadas através de um modelo proposto para mensurar o papel do grau de fibrose, do sexo, da idade e da dose de ribavirina nas alterações antropométricas, utilizando métodos estatísticos como a análise de resíduo e o coeficiente de determinação ajustado. Foi possível observar que o tratamento antiviral levou a reduções de várias medidas antropométricas, e o modelo utilizado mostrou que as principais variáveis envolvidas nessas alterações foram a idade e o sexo, sem que houvesse papel relevante do grau de fibrose ou das doses de ribavirina. / Chronic hepatitis C is a disease caused by the hepatitis C virus and causes chronic hepatic inflammation, which can lead to cirrhosis, terminal liver failure and hepatocellular carcinoma. The treatment aims to stop viral replication definitively, but when using pegylated interferon and ribavirin some side effects are common, such as weight loss, which can lead to treatment discontinuation. The hypothesis of this study was that the degree of liver fibrosis and the ribavirin doses could have a role on the reductions of anthropometric measures during antiviral treatment. The aim was to assess the relationship between the degree of hepatic impairment, ribavirin doses, age, gender and anthropometric changes in patients with chronic hepatitis C submitted to 24 weeks of treatment with pegylated interferon and ribavirin. Seventy-six patients were included and their weight, height, triceps skin fold, arm circumference, arm muscle circumference and arm muscle area were measured before and after 24 weeks of treatment. Epidemiological data and liver biopsy findings were obtained from patients' charts. The sample was divided into two groups according to the presence or absence of advanced hepatic fibrosis. The values observed in each group were compared by paired t test or Wilcoxon test. Then, the anthropometric changes throughout the antiviral treatment by a model aimed to measure the role of fibrosis degree, age, sex and ribavirin doses on the anthropometric changes, using statistical methods such as residual analysis and adjusted determination coefficient. It was possible to observe that the antiviral treatment caused reductions of many anthropometric measures, and the model proposed showed that the main variables involved in such reductions were age and sex, without a significant role that could be attributed to the degree of liver fibrosis or to the ribavirin doses.

Orientador: Paula Rahal / Banca: João Renato Rebello Pinho / Banca: Maurício Lacerda Nogueira / Resumo: O HCV é uma das maiores causas de doença do fígado, sendo estimado que mais de 2% da população mundial está infectada. Este vírus possui um genoma de RNA (+) fita simples, que devido à falta de atividade corretiva da polimerase viral apresenta variabilidade genética em vários níveis: genótipos, subtipos e quasispecies. O genótipo 1 é o mais prevalente no Brasil e no mundo, sendo preditivo de uma baixa resposta à terapia antiviral, que atualmente é baseada na administração de PEG-IFN e ribavirina. A variabilidade genética da região viral NS5A tem sido relacionada à sensibilidade ou resistência ao IFN. Este estudo teve como objetivo investigar se a possível relação entre a composição de quasispecies da NS5A e a resposta ao tratamento. Foram selecionados 12 pacientes, sendo 4 respondedores (R), 4 não respondedores (NR) e 4 respondedores ao final do tratamento (RFT). As amostras pré-tratamento destes pacientes foram amplificadas, clonadas e seqüenciadas, resultando em 165 seqüências da NS5A completa. Estas seqüências foram alinhadas, editadas e a construção da topologia da árvore filogenética foi realizada. A NS5A e suas regiões específicas CRS, PKR-binding, ISDR, NLS e V3 foram analisadas quanto às substituições e o grau de variabilidade genético. O grupo de pacientes RFT apresentou uma maior taxa de substituições sinônimas em relação aos demais grupos. Uma maior quantidade de mutações foi observada na região downstream à ISDR, principalmente na região V3. Nenhum sítio específico de mutação foi relacionado a um tipo particular de resposta, e não houve agrupamento filogenético das quasispecies de acordo com o tipo de resposta. Estes resultados sugerem que o número de mutações não é suficiente para predizer a sensibilidade ou resistência à terapia baseada em IFN, sendo necessário avaliar se estas mutações conservaram ou não as propriedades químicas dos aminoácidos. / Abstract: Hepatitis C virus (HCV) is major causes of liver desease and about 2% of world s population are infected. This virus is a single strain RNA genome of approximately 9.6 kb. Genetics variability of HCV exists at several different levels: genotypes, subtypes and quasispecies. The high mutation rates are related to the low fidelity of viral RNA polymerase. Genotype 1 HCV is the most prevalent in Brazil, as well as worldwide. Genotypes 1a and 1b are predictive of lower sustained virological response in peginterferon (PEG-IFN) plus ribavirin combination therapy. Genetic variability of viral NS5A has been related to IFN sensibility or resistance. To evaluate whether HCV NS5A quasispecies composition are related to responsiveness to combined PEG-IFN and ribavirin therapy, this study analyzed before treatment sample of 12 treated patients (4 sustained responders - SR, 4 non responders - NR and 4 end of treatment responder - ETR). Samples were amplified, cloned and sequenced, resulting in 165 sequences of complete NS5A. Sequences were aligned, edited and phylogenetical tree was constructed. Mutations and mean of genetic distance were analyzed to NS5A and specific regions CRS, PKR-binding, ISDR, NLS and V3. The number of synonymous substitutions per synonymous sites was higher in ETR patients than in other patient groups. Mutations were more common downstream ISDR, mainly concentrated in V3 domain. No single amino acid position or motif was associated with different responses to therapy in any NS5A regions analyzed and phylogenetic analysis did not show clustering of nucleotide sequences of viral isolates from SR, NR or ETR. These results suggest that number of mutations is not sufficient to predict sensibility or resistance to IFN based therapy. Other studies are necessary to evaluate whether chemical characteristics of amino acids were altered for the mutations. / Mestre

A infecção pelo vírus da hepatite C acomete cerca de 180 milhões de pessoas em todo mundo. Trata-se de doença com pouca manifestação clinica, onde cerca de 75% a 85% dos casos evolui para cronificação e aproximadamente 15% para hepatocarcinoma. Entre os fatores de risco mais conhecidos estão a realização de transfusões de sangue e hemoderivados anterior a 1993, uso de drogas endovenosas e relações sexuais desprotegidas. Este trabalho tem por objetivo estimar a prevalência de sorologia positiva para hepatite C e seus possíveis fatores de risco no distrito de Botafogo, município de Bebedouro, SP, onde a elevada freqüência de casos de hepatite chamou a atenção dos seus próprios moradores. Da população de 1318 habitantes, 353 foram sorteados para participar da pesquisa, sendo submetidos a questionário padronizado e coleta de sangue. Infecção pelo vírus da hepatite C foi pesquisada através de exames imunoenzimáticos e de PCR, no Instituto Oswaldo Cruz (Fiocruz), e por teste imunocromatográfico, no Laboratório de Sorologia do Hospital da Clínicas de Ribeirão Preto-USP . A prevalência encontrada foi de 8,8% (IC95%: 5,8 11,7). As variáveis que mostraram associação na análise univariada foram submetidas a um procedimento multivariado por aplicação do modelo de log binomial. As variáveis preditoras independentes de infecção pela hepatite C foram sexo masculino, tempo de residência acima de trinta anos e uso de medicações parenterais com material esterilizado por técnica de fervura. Uma possível explicação para a elevada prevalência nessa população reside na possibilidade de disseminação do vírus a partir de um antigo morador, que exercia informalmente atividades ligadas ao atendimento à saúde, especialmente aplicação de injeções, numa época anterior ao uso de seringas descartáveis. / Approximately 180 million people worldwide are infected by the hepatitis C virus. It is an illness with little clinical manifestation where about 75% - 85% of the cases evolve to chronification and about 15% to hepatocarcinoma. Among the bestknown risk factors are blood and blood by-product transfusions prior to 1993, use of intravenous drugs and unprotected sexual relations. This study has the objective of estimating the prevalence of positive serology for hepatitis C and its possible risk factors in the district of Botafogo, municipality of Bebedouro, São Paulo, where the high frequency of hepatitis cases caught the attention of the population itself. Out of a population of 1318 inhabitants, 353 were selected to participate in the research, being submitted to a standard questionnaire and blood collection. Hepatitis C infection was researched through immunoenzimatic and PCR exams at the Oswaldo Cruz Institute (FIOCRUZ), and by immunochromatographic tests at the Serology Laboratory of the Hospital das Clinicas in Ribeirão Preto USP. The prevalence found was of 8,8% (CI95%: 5,8 11,7). The variables that demonstrated an association in the univariate analysis were submitted to a multivariate procedure through the application of the binomial log model. The independent predictors for hepatitis C infection were male sex, local residence time over thirty years and use of parenteral medication with material sterilized through boiling technique. A possible explanation for the high prevalence in this population lies in the possibility of dissemination of the virus from an older inhabitant who informally exercised medical activities, especially the application of injections in a period before there was use of dischargeable syringes.

Foram estudados 151 doadores de sangue encaminhados pelo Hemocentro de Ribeirão Preto ao Ambulatório de Hepatites do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto em função de terem apresentado resultados foram positivos para hepatite C nos testes de triagem pré-doação, entre 2001 e 2010. Todos tiveram confirmação diagnóstica mediante uso de técnicas de biologia molecular. No momento de chegada ao Hospital foram entrevistados por uma assistente social ligada ao Núcleo Hospitalar de Epidemiologia, com o objetivo de caracterizá-los segundo variáveis sociodemográficas, estudar fatores de risco presentes e genótipos encontrados. Houve predominância de indivíduos do sexo masculino, com baixos níveis de escolaridade e de estratos sociais menos favorecidos, com idade mediana de 36 anos. Observou-se uma tendência decrescente de infectados ao longo dos anos estudados. O genótipo mais prevalente foi o 1 com percentual de 68,8%, seguido do genótipo 3 (27,0%). Os potenciais fatores de risco mais prevalentes foram história pregressa de hospitalização sem e com cirurgia, multiplicidade de parceiros sexuais no passado, convivência com usuários de drogas, contato com sangue em atendimentos a terceiros, múltiplos parceiros sexuais no presente e contato domiciliar com casos de hepatite. Também com elevadas frequências foram observados os seguintes fatores: antecedente de transfusão sanguínea, uso coletivo de escova de dentes, história de contato sexual com usuários de drogas, frequência a creches na infância e tatuagem. Uso passado de drogas injetáveis e compartilhamento de seringas e agulhas foram relatados por 15,2% e 9,9%, respectivamente. Conclui-se que deve ter ocorrido omissão de inúmeros fatores de risco por ocasião da triagem clínica, possivelmente indicativo do desejo de se utilizar o Banco de Sangue como controle da situação sorológica por parte de parte dos doadores. / 151 blood donators were analyzed sent from the Hemocenter of Ribeirão Preto to the Hepatitis Clinic of the University Hospital of the Ribeirão Preto Medical School, University of São Paulo, because these individuals had presented positive results for Hepatitis C in the screening tests for pre-donation, taken between 2001 and 2010. All of them had diagnosis confirmation through the use of molecular biology techniques. At the moment of arrival in the hospital, they were interviewed by a Social Assistant from the Hospital Nucleus of Epidemiology, in order to characterize them according to socio-demographic variables, to study risk factors that might be present, and genotypes found. The predominance was of male individuals, with low school levels, and coming from a less favored social stratum, with a median age of 36 years. There was a decreasing tendency of infected individuals along the years of study. The most prevailing genotype was type 1 with a percentage of 68.8%, followed by the genotype 3 (27.0%). The most prevailing potential risk factors were previous history of hospitalization with and without surgery, multiplicity of sexual partners in the past, acquaintance with drug user, contact with blood on dealing with to third parties, multiple current sexual partners and home contact with hepatitis cases. The following factors were also observed with high frequency: antecedent of blood transfusion, collective use of tooth brush, history of sexual contact with drug users, attendance to day care clinics in childhood and tattoos. Past use of injectable drugs and syringe and needle sharing were reported by 15.2% and 9.9%, respectively. The conclusion was that there must have been the omission of a number of risk factors at the time of the clinical screening, possibly indicating the desire of using the Blood Bank to make control of the serological status by some of the donators

Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-07-31T13:41:46Z No. of bitstreams: 1 Mariane de Amarante Souza.pdf: 1596658 bytes, checksum: 44d5d39f8f8a41833027151f10b44e37 (MD5) / Made available in DSpace on 2017-07-31T13:41:46Z (GMT). No. of bitstreams: 1 Mariane de Amarante Souza.pdf: 1596658 bytes, checksum: 44d5d39f8f8a41833027151f10b44e37 (MD5) Previous issue date: 2017-05-25 / Introduction: Hepatitis C virus (HCV) is an RNA virus with six different genotypes (1 to 6). This virus is mainly transmitted through parenteral route. An estimated 170 million individuals are HCV carriers worldwide. HCV infection is considered as the main cause of liver cirrhosis in the West. The natural history of HCV is related to viral and host factors. Among the latter, type 2 diabetes mellitus (T2DM) has been related with more rapid progression of liver fibrosis. Aim: To evaluate HCV carriers and identify factors associated with more advanced degrees of liver fibrosis. Methods: A cross-sectional study with chronic HCV carriers. The study was performed at the Center for Liver Study Outpatient Clinic of the Presidente Dutra University Hospital, Federal University of Maranhão, São Luís, Maranhão, northeast Brazil. The patients had their medical records analysed. The subjects with the following features were not enrolled for this study: incomplete data, HIV or HBV coinfection, end-stage chronic renal disease on dialysis and individuals who underwent kidney or liver transplantation. Demographic data (sex and age), alcohol intake (yes or no), T2DM (presence or absence), HCV genotype and degrees of liver fibrosis were retrieved from the patients’ medical records. The patients were classified as less or more advanced fibrosis. Both groups were compared to demographic variables, viral genotypes, T2DM presence and alcohol intake. We used the chi-square test and student’s t-test for nominal and numerical variables respectively. Multivariate logistic regression analysis was performed to identify factors independently associated with more advanced degrees of liver fibrosis. We used the SPSS version 23.0 for statistical analyses. Results: A total of 235 patients participated of this study. These patients had complete data on their medical records and met all the inclusion and exclusion criteria. Most of them were male (138/235; 59%) ranging from 18 to 78 years of age (53 ± 10). They were associated with more advanced degrees of fibrosis: Age (OR=1.061, 95% CI: 1.025- 1.098, p<0.001), presence of T2DM (OR 2.227, 95%CI: 1.059-4.142, p = 0.035) and alcohol intake (OR 1.921, 95%CI: 1.129-3.269, p=0.036). Conclusion: T2DM was associated with more advanced degrees of liver fibrosis among the HCV carriers. Thus, diagnosis and treatment of HCV carriers with diabetes are of great importance for interrupting the progression of liver cirrhosis. / Introdução: O vírus da Hepatite C (HCV) é um RNA vírus, que apresenta seis genótipos diferentes (1 a 6) e é transmitido por via predominantemente parenteral. Existem cerca de 170 milhões de indivíduos portadores do HCV em todo o mundo. É a principal causa de cirrose hepática no mundo ocidental. A história natural da infecção pelo HCV é modulada pela interação de fatores virais e do hospedeiro. Entre os fatores associados ao hospedeiro, Diabetes mellitus tipo 2 (T2DM) tem sido associada a maior progressão da doença hepática. Objetivo: avaliar portadores do HCV e identificar fatores associados a graus mais avançados de fibrose hepática. Metodologia: Estudo transversal com portadores da infecção crônica pelo HCV. Foram analisados dados dos prontuários de pacientes atendidos no ambulatório do Núcleo de Estudo do Fígado do Hospital Universitário da Universidade Federal do Maranhão, excluídos portadores de co-infecção com vírus da imunodeficiência humana (HIV) ou vírus da hepatite B (HBV), portadores de doença renal crônica terminal em diálise e transplantados de fígado ou rim. Resgatados dados demográficos (idade e gênero), graus de fibrose hepática, genótipo viral, história de ingestão alcoólica e diagnóstico de T2DM. Os portadores foram categorizados em graus mais e menos avançados de fibrose e comparados quanto aos dados demográficos (idade e sexo), genótipo viral, presença ou não de T2DM e ingestão alcoólica. Diferenças entre variáveis numéricas foram calculadas pelo teste t de Student e entre nominais pelo Quiquadrado. Foi realizada regressão logística multivariada para identificar fatores independentemente associados com graus mais avançados de fibrose. O programa SPSS versão 23.0 foi utilizado. Resultados: Incluídos 225 pacientes, a maioria do sexo masculino (138/235, 59%), com média de idade 53 ± 10 anos. Foram associados a graus mais avançados de fibrose: idade (OR=1,061 (IC 95% 1.025-1,098) P<0.001), presença de T2DM (OR 2,227 (IC 95% 1,059-4,142) P= 0,035) e ingestão alcoólica (OR 1,921(IC 95% 1,129-3,269) P=0,036). Conclusão: Entre portadores crônicos do HCV no Maranhão, a presença de T2DM esteve associada a graus mais avançados de fibrose hepática, sugerindo que é importante o diagnóstico da infecção crônica pelo HCV entre diabéticos, para que o tratamento da infecção seja feito, prevenindo progressão para cirrose hepática.

Hepatitis C virus (HCV) infection is the most common blood-borne infection in the United States (U.S.). The largest increases of incidence for HCV infection are reported in the Appalachian region. This study aimed to 1) examine the prevalence and trends of HCV infection in the U.S. from 1999 to 2012; 2) investigate barriers to HCV infection treatment in Northeast Tennessee and the U.S.; and 3) study characteristics and risk factors for HIV-infection and HCV-infection in Northeast Tennessee. In the U.S., data were obtained from the National Health and Nutrition Examination Survey (NHANES) 1999-2012 to study the prevalence of HCV infection and barriers to treatment. In Northeast Tennessee, hepatitis C and HIV/AIDS data were obtained from National Electronic Disease Surveillance System (NEDSS) and enhanced HIV/AIDS Reporting System (eHARS). Descriptive statistics and multiple logistic regression models were used for analysis. Odds ratios (OR) and 95% confidence intervals (CI) were reported. There was an estimated 3.8 million people having HCV antibody in the U.S. in 2012. No significant change was found in the prevalence of HCV infection during 1999 – 2012. The leading barrier to the treatment was cost issues in the U.S. (50.0%) and Northeast Tennessee (25.0%), respectively. HCV patients without symptoms in Northeast Tennessee were more likely to be untreated (OR: 3.08, 95% CI: 1.10-8.60) and patients without health insurance in the U.S. were more likely to be untreated than their counterparts (OR: 3.38, 95% CI: 1.14-10.05). The incidence of acute hepatitis C peaked in 2012-2013 in Northeast Tennessee, while the incidence of HIV/AIDS increased by 100% from 2013 to 2015. More injection drug users (IDUs) and less men who have sex with men (MSM) were observed in patients with HCV infection than in those with HIV infection (IDUs: 50.63% vs.16.38% p

Hepatitis (HCV) is a communicable disease that impacts many Americans. The scholarly literature lacked the knowledge pertaining to the relationships between poverty and HCV diagnosis and prescription for HCV medication. The purpose of the study was to measure the magnitude and statistical significance of these relationships, as modeled by the health belief model and public health surveillance and action framework. Specifically, the study was designed to determine whether there is a statistically significant relationship between living below the poverty line and being diagnosed with HCV, as well as living being below the poverty line and being prescribed HCV medication. A total of 78 records of HCV-positive individuals from the National Health and Nutrition Examination Survey dataset were evaluated by applying the statistical procedure of odds ratio (OR) analysis. The results of the analysis revealed that (a) there was not a statistically significant relationship between being below the poverty line and being diagnosed with HCV, OR = 0.99 (SE = 0.38, z = -0.03, p = .974); and (b) there was not a statistically significant relationship between being below the poverty line and being prescribed HCV medications, OR = 0.32 (SE = 0.55, z = -0.66, p = .507). Numerous recommendations for improving measurements of the relationship between poverty and HCV are provided. This study may promote positive social change by indicating the importance of poverty as an agenda item for public health policy and practice.

Lorsque l'hépatite chronique C a occasionné une cirrhose et que, du fait de ses complications, le pronostic vital est en jeu au terme de quelques mois, la transplantation hépatique (TH) représente l'unique traitement efficace,. Malheureusement, la récidive quasi-systématique de la cirrhose C, après la transplantation hépatique, est la principale barrière à la survie du greffon. De nombreux facteurs ont été associés à la sévérité des récidives, et une implication des lymphocytes T régulateurs CD4+CD25+ (Treg) et de certains immunosuppresseurs a été suggérée. Par ailleurs, le patient transplanté peut également être confronté au problème du rejet aigu d’allogreffe, qui est partiellement contrôlé par les Treg et par une thérapie immunosuppressive rigoureuse. Paradoxalement, plusieurs études ont suggéré que certains immunosuppresseurs sont moins efficaces que d’autres dans la prophylaxie du rejet d’allogreffe et peuvent même être associés à des épisodes de rejet plus fréquents. Il existait donc un besoin urgent d’évaluer le rôle joué par les immunosuppresseurs sur les Treg dans la récidive de la fibrose C et dans le rejet du greffon. Dans un premier temps, nous avons confirmé l’implication des Treg dans la progression de la récidive de l’hépatite C. En effet, les marqueurs associés à cette population sont surexprimés dans le foie et dans le sérum de patients, 1 an et 5 ans après la TH, et ce proportionnellement à la sévérité de la récidive. Dans un deuxième temps, nous avons évalué l’effet d’immunosuppresseurs utilisés après la TH (cyclosporine A (CsA), tacrolimus, rapamycine et mycophénolate mofétif) sur l’activité des Treg. Nous avons ainsi montré que seule la CsA a une action inhibitrice sur l’activité des Treg, et ce, uniquement aux doses thérapeutiques de 20 et 40 ng/mL (doses administrées au long terme, 5 ans après la TH). Cette inhibition de l’activité des Treg par la CsA ne modifie pas leur phénotype (expression protéique ou génique), mais conduit à la sécrétion d’IL-2 et d’IFN-&#947; par les Treg, cytokines de la voie Th1. Le mécanisme immunosuppresseur de la CsA étant d’inhiber la transcription de l’IL-2, via la voie calcineurine/N-FAT, nous avons tenté d’identifier si elle agissait sur les Treg par cette voie ou par une voie indépendante de la calcineurine. Deux observations ont renforcé l’hypothèse d’un mode d’action calcineurine/N-FAT - indépendant : (i) le fait que le tacrolimus, qui a le même mécanisme immunosuppresseur que la CsA, n’inhibe pas l’activité des Treg et (ii) le fait que NIM811, un analogue de la CsA n’agissant pas sur la voie de la calcineurine, inhibe l’activité des Treg aux mêmes doses que la CsA. Cette hypothèse a par ailleurs été directement confirmée par l’absence de modification du profil de déphosphorylation du facteur de transcription N-FAT, en présence de CsA. Enfin, bien que les corticoïdes soient connus pour préserver l’activité des Treg et induisent leur prolifération in vitro, ils sont incapables de reverser l’effet inhibiteur de la CsA sur les Treg. Nos résultats suggèrent donc qu’une dose thérapeutique de CsA inhiberait l’activité des Treg CD4+CD25+. Les cellules T régulatrices jouent un rôle important dans la tolérance du greffon et dans la sévérité des récidives après la TH, leur inhibition par la CsA pourrait alors favoriser le rejet du greffon et diminuer la sévérité des récidives. Ces résultats sont importants dans la mesure où la transplantation hépatique est à l’heure actuelle la seule alternative de survie au stade du carcinome hépatocellulaire, et qu’il n’existe aucun traitement efficace contre le rejet du greffon ou la récidive de l’hépatite C. Le traitement immunosuppresseur idéal n’existe pas, cependant il ne devrait pas augmenter l’activité suppressive des Treg, au risque de favoriser la récidive de l’hépatite C, ni inhiber cette activité, au risque de favoriser le rejet du greffon. / Liver transplantation (LT) remains the only effective therapeutic approach for cirrhosis related HCC patients. Inevitable hepatitis C virus (HCV) recurrence after liver transplantation is a major barrier to the survival of a transplanted liver. It may be promoted by immunosuppression and the emergence of CD4+CD25+ regulatory T cells (Treg). Transplanted patients are also been confronted to allograft rejection, which is partially controlled by Treg cells and the administration of an immunosuppressive therapy. However, some immunosuppressive drugs have been associated with more frequent graft rejection. In this context, it was important to assess the effect of immunosuppressive drugs on regulatory T cells, both in HCV recurrence and graft rejection. We have first confirmed the implication of Treg cells in hepatitis C recurrence progression. Indeed, regulatory T cells markers are over-expressed, 1 and 5 years after LT, both in the liver and in periphery and proportionally of the recurrence severity. In a second time, we have analysed the effect of immunosuppressive drugs used after LT (cyclosporine A (CsA), tacrolimus, rapamycine and mycophenolate mofetil) on regulatory T cell activity. We have shown that only low concentrations of CsA (20 and 40 ng/mL) inhibit regulatory T cell activity (these doses are used 5 years after LT). It seems that CsA does not affect regulatory T cell phenotype (protein and gene expression) but lead to a secretion of Th1 cytokines in Treg cells : IL-2 and IFN-&#947;. As CsA, is known to inhibit IL-2 transcription through the calcineurin/N-FAT pathway, we have tried to identify if CsA inhibits Treg cells via this pathway or via a calcineurin -independent pathway. Two observations have confirmed the hypothesis of a calcineurin -independent pathway : (i) tacrolimus, which have the same immunosuppressive mechanism as CsA, could not inhibit Treg activity, and (ii) NIM811, a calcineurin - independent CsA analog, inhibits regulatory T cell activity at the same concentrations than CsA. Moreover, this hypothesis has been directly confirmed by the absence of of modification of the N-FAT dephosphorylation profile. Lastly, corticoids, known to preserve Treg activity, could induce Treg cell proliferation in vitro. However, they could not reverse the inhibitory effect of CsA on Treg cells. Our results suggest that a therapeutical dose of CsA could inhibit CD4+CD25+ regulatory T cell activity. Treg cells play an important role in graft tolerance and hepatitis C recurrence after LT, so their inhibition by CsA could favour graft rejection and decrease recurrence severity. These results are important, as liver transplantation iscurrently the only survival alternative for HCC related patients. The ideal immunosuppressive therapy does not exist, but it would not increase Treg activity, which may promote hepatitis C recurrence, neither abrogate this activity due to the risk of graft rejection.

L’infection par le virus de l’hépatite C (HCV) évolue dans la plupart des cas en hépatite chronique et peut conduire à une cirrhose ou un carcinome hépatocellulaire. Malgré les grandes avancées dans le traitement de l’hépatite C qui permettent d’inhiber ou même de bloquer l’évolution de cette infection vers la chronicité, l’absence de vaccin ainsi que sa répartition sur la surface du globe nous permet de classer cette pathologie en problème majeur de santé publique. La majorité des traitements actuels ciblent les protéines virales et leur fonction. Cependant un grand nombre de mécanismes du cycle viral de HCV reste à élucider.Comme pour la grande majorité des virus à ARN de polarité positive, la réplication de HCV a lieu dans des membranes cellulaires modifiées. Le remaniement de ces membranes est en lien étroit avec la voie de sécrétion précoce de la cellule. Il a été montré que GBF1, un facteur d’échange nucléotidique des protéines G de la famille Arf qui régulent la dynamique membranaire, est un facteur nécessaire à la réplication de HCV. L’inhibition de GBF1 par la bréfeldine A (BFA) inhibe la voie de sécrétion des protéines cellulaires néosynthétisées et inhibe aussi la réplication de HCV. Pour étudier le rôle de GBF1 pendant l’infection nous avons établi des lignées résistantes à la BFA. Deux de ces lignées étaient 100 fois plus résistantes que les lignées parentales à l’apoptose induite par la BFA, à l’inhibition de la sécrétion des protéines et à l’inhibition de l’infection par HCV. Ce phénotype était dû à une mutation ponctuelle dans le domaine catalytique sec7 de GBF1 de ces lignées. Un autre groupe de lignées était partiellement résistantes à l’inhibition de la sécrétion des protéines par la BFA tout en conservant un niveau d’infection proche de celui des lignées parentales dans les mêmes conditions. Ces résultats suggèrent que la fonction de GBF1 pendant l’infection HCV ne serait pas réduite à la régulation de la voie de sécrétion, évoquant ainsi un rôle additionnel de GBF1 nécessaire pour la réplication de HCV.Par ailleurs, nous avons pu montrer à l’aide des mutants de délétion de la protéine GBF1, que l’activité catalytique du domaine sec7 était nécessaire. Ceci suggère l’implication d’une protéine de la famille Arf dans l’activation de l’infection HCV via GBF1. L’implication de Arf dans l’infection HCV a été confirmée par la surexpression de dominants négatifs de la protéine Arf1 et par l’inhibition de l’activité de l’ArfGAP1 (régulateur des Arf) par l’inhibiteur spécifique QS11.Nous avons ensuite testé l’implication des différents Arf sensibles à l’inhibition par la BFA (Arf1, 3 ,4 et 5), dans l’infection HCV à l’aide de si-RNA. Il a été montré que ces protéines Arf possèdent des fonctions redondantes. Nos résultats confirment l’implication de Arf1 et indiquent que les 3 autres protéines sont aussi impliquées dans l’infection HCV. D’une manière intéressante, la déplétion combinée des Arf inhibe fortement l’infection HCV suggérant ainsi un rôle essentiel de certaines protéines Arf, probablement en activant des facteurs cellulaires nécessaires à l’étape de réplication. L’étude des facteurs cellulaires impliqués dans l’infection HCV permet de mieux comprendre l’étape de réplication et par conséquent le cycle viral de HCV. Par ailleurs, l’étude de ces facteurs pourrait permettre le développement éventuel de stratégies antivirales ciblant des facteurs de la cellule hépatique indépendamment du génotype viral, limitant ainsi le risque d’émergence de variants résistants au traitement. / The hepatitis C virus (HCV) infection progresses in most of the cases into a chronic hepatitis and can lead to cirrhosis or hepatocellular carcinoma. Despite the recent improvement of hepatitis C treatments, which inhibit or even block the progress of this infection into a chronic stage, a vaccine still not available and the worldwide distribution of the disease makes the hepatitis C a major public health problem. Most of the available treatments target viral proteins. However many mechanisms of the HCV life cycle remain unclear.As for many positive RNA viruses, HCV replication occurs in reorganized cellular membranes. These membrane rearrangements are closely linked to the early secretory pathway of the cell. It has been shown that GBF1, an exchange factor of small G proteins of the Arf family that regulates the membrane dynamics in the secretory pathway, is required for HCV replication. GBF1 inhibition by brefeldin A (BFA) inhibits the secretion of newly synthesized proteins and also inhibits HCV replication. To investigate the role of GBF1 in HCV infection, we isolated cell lines resistant to BFA. Two of these cell lines were 100 times more resistant than the parental cells to BFA-induced apoptosis, inhibition of proteins secretion and inhibition of HCV infection. This resistance was due to a point mutation in the catalytic sec7 domain of GBF1 of these cells. Another group of resistant cells was showing a partial resistance to the inhibition of proteins secretion while maintaining their sensitivity to the inhibition of HCV infection in the same conditions. These results suggest that GBF1 might fulfill another function, in addition to the regulation of the secretory pathway, during HCV replication. Using GBF1 deletion mutants we showed that the catalytic activity of the sec7 domain of GBF1 is required for HCV infection. This suggests that the function of GBF1 during HCV replication is mediated by Arf activation. The involvement of Arf was confirmed with the overexpression of restricted mutants of Arf1 and by the inhibition of ArfGAP1, another regulator of Arf function. We then tested the possible involvement of different Arfs (Arf1, 3, 4 and 5) in HCV infection. It has been reported that Arfs have redundant functions. The results confirm the involvement of Arf1 and indicate that all the other BFA-sensitive Arfs (Arf3, Arf4 and Arf5) are also involved in HCV infection. The combined knockdown of Arfs strongly inhibited HCV replication, showing that the Arf proteins are working together in HCV replication probably by activating several host factors required for the virus life cycle.The study of cellular factors required for HCV infection is crucial to better understand the interaction of the virus with the host cell and thus the whole HCV life cycle. This could help to develop new therapies targeting the host cell, regardless of viral genotypes and reducing the risk of emergence of new resistant forms.