Hepatitis C virus (HCV) infection is common among injection drug users (IDUs). There is accumulating evidence that circulating microRNAs (miRNAs) are related to HCV infection and disease progression. The present study was undertaken to determine the in vivo impact of heroin use on HCV infection and HCV-related circulating miRNA expression. Using the blood specimens from four groups of study subjects (HCV-infected individuals, heroin users with/without HCV infection, and healthy volunteers), we found that HCV- infected heroin users had significantly higher viral load than HCV-infected non-heroin users (p=0.0004). Measurement of HCV-related circulating miRNAs in plasma showed that miRs-122, 141, 29a, 29b, and 29c were significantly increased in the heroin users with HCV infection, whereas miR-351, an HCV inhibitory miRNA, was significantly decreased in heroin users as compared to control subjects. Further investigation identified a negative correlation between the plasma levels of miR-29 family members and severity of HCV infection based on aspartate aminotransferase to platelet ratio index (APRI). Heroin use and/or HCV infection also dysregulated a panel of plasma miRNAs. Taken together, these data for the first time revealed in vivo evidence that heroin use and/or HCV infection alter circulating miRNAs, which provides a novel mechanism for the impaired innate anti-HCV immunity among IDUs. Recent studies revealed that extracellular miRNAs were able to incorporate into cell-derived exosomes as a method of cell-to-cell interaction. Exosomes are a class of cell-released small vesicles that mediate intercellular communication by delivering functional factors to recipient cells. During HCV infection, the interaction between liver resident macrophages and hepatocytes is important for host defense and viral elimination, triggered by innate immune activation, especially Toll like receptors (TLR). In our study, we explored the role of macrophage-derived exosomes in the transmission of innate immune responses against HCV infection in hepatocytes, and the involvement of exosomal miRNAs in transferring the anti-HCV activities. We reported that upon TLR3 activation, macrophages shed exosomes that were able to attenuate HCV-JFH1 infection in Huh7 cells. We further demonstrated that exosomes from poly I:C treated macrophages were internalized by Huh7 cells, which induced the intercellular anti-HCV responses (type I interferon, interferon stimulated genes, etc.) and thus drastically inhibited HCV infection in Huh7 cells. Moreover, using an in vitro macrophage and Huh7 cell co-culture model, we also found exosomes mediated HCV suppression in Huh7 cells after TLR3 activation. The presence of exosome inhibitor in co-culture compromised the anti-HCV activity by TLR3-activated macrophages. Interestingly, the miRNA-29 family, which was reported to suppress HCV infection, was significantly increased in the macrophage exosomes after TLR3 activation. The inhibition of miRNA-29 partially compromised the anti-HCV activity of TLR3-activated macrophages, indicating the potential involvement of exosomal miRNAs in the transmission of anti-HCV activity from macrophages to Huh7 cells through exosomes. In conclusion, this study proposed an antiviral mechanism of TLR3 activation that involves the intercellular communication between immune cells and hepatic parenchymal cells via exosomes, and exosomal miRNAs. This discovery sheds light on exploiting the therapeutic potential of new drugs against HCV infection. / Pathology

Hepatitis E virus (HEV), the causative agent of hepatitis E, is endemic in many developing countries. However, sporadic cases of acute hepatitis E have also been reported in industrialized countries including the United States. Increasing evidence suggested that hepatitis E is zoonotic. Swine HEV was discovered in 1997 from a pig in the United States and has the ability to cross species barrier and infect humans. There are four major genotypes of HEV worldwide and swine HEV identified to date in different countries belongs to either genotypes 3 or 4. Thus far, genotypes 1 (Asian strains) and 2 (a single Mexican strain) of HEV are exclusively found in humans. To determine if genotypes 1 and 2 of HEV also exist in pigs we tested serum and/or fecal samples for from pigs of different age groups in Thailand, and from pigs 2-4 months-of-age in two states (Sonora, Sinaloa) in Mexico. A universal RT-PCR was first standardized to detect all 4 different genotypes of HEV. Swine HEV RNA was detected from in 10/26 pigs at 2-4 months-of-age but not in pigs of 1-, 6-month old, adult/sow pigs from Thailand. In Mexico, swine HEV RNA was detected in 8 of 125 serum samples, 28 of 92 fecal samples of 2-4 month-old pigs. Antibodies to swine HEV were detected in 101 of 125 (80.8%) Mexican pigs. A total of 44 swine HEV isolates were amplified and sequenced for the ORF2 capsid gene region. Sequence analyses revealed that all the swine HEV isolates identified from pigs in Thailand and Mexico belong to genotype 3. Overall, the Mexican swine HEV isolates shared 89-100% sequence identity to each other, and about 89-92% identity with the prototype genotype 3 US swine HEV. The Thailand swine HEV isolates displayed 97-100% nucleotide sequence identity with each other, and 90-91% identity with the prototype genotype 3 swine HEV. Phylogenic analysis revealed that minor branches do exist among Mexican swine HEV isolates. The results from this study indicated that genotype 1 or 2 swine HEV does not exist in pig from countries where human genotypes 1 and 2 HEVs are prevalent. / Master of Science

Mathematical models have long been used to describe complex biological interactions with the aim of predicting mechanistic interactions hard to distinguish from data. This dissertation uses modeling, mathematical analyses, and data fitting techniques to provide hypotheses on the mechanisms of immune response formation and function. The immune system, comprised of the innate and adaptive immune responses, is responsible for protecting the body against invading pathogens, with disease or vaccine induced immune memory leading to fast responses to subsequent infections. While there is some agreement about the underlying mechanisms of adaptive immune memory, innate immune memory is poorly understood. Stimulation with lipopolysaccharide induces differential phenotypes in innate immune cells depending on the strength of the stimulus, such that a secondary lipopolysaccharide encounter of a constant dose results in either strong or weak inflammatory cytokine expression. We model the biochemical kinetics of three molecules involved in macrophages responses to lipopolysaccharide and find that once a macrophage is programed to show a weak inflammatory response this cannot be reverted. Contrarily, a secondary lipopolysaccharide stimulus of a very high dose or applied prior to waning of the effects of the primary stimulus can induce a phenotype switch in macrophages initially programed to show strong inflammatory responses. Some pathogens, such as the hepatitis B virus, have developed strategies that hinder an efficient innate immune response. Hepatitis B virus infection is a worldwide pandemic with approximately 257 million chronically infected people. One beneficial event in disease progression is the seroclearance of hepatitis B e antigen often in combination with hepatitis B antibody formation. We propose mathematical models of within-host interactions and use them to predict that hepatitis B e antibody formation causes hepatitis B e antigen seroclearance and the subsequent reactivation of cytotoxic T cell immune responses. We use the model to quantify the time between antibody formation and antigen clearance and the average monthly hepatocyte turnover during that time. We further expand the study of hepatitis B infection, by investigating the kinetics of the virus under an experimental drug administered during a clinical trial. Available drugs usually fail to induce hepatitis B s antigen clearance, defined as the functional cure point of chronic hepatitis B infections. Drug therapy clinical trials that combined RNA interference drug ARC-520 with entecavir have shown promising results in reducing hepatitis B s antigen titers. We develop pharmacokinetic-pharmacodynamic models describing the mechanistic interactions of the drugs, hepatitis B virus DNA, and virus proteins. We fit the model to clinical trial data and predict that ARC-520 alone is responsible for the reduction of hepatitis B s and e antigens, while entecavir is the driving force behind viral reduction. This work was supported by Simons Foundation, Grant No. 427115, and National Science Foundation, Grant No. 1813011. / Doctor of Philosophy / Mathematical models have long been used to describe complex biological interactions with the aim of predicting interactions that explain observed data and informing new experiments. This dissertation uses modeling, mathematical analyses, and data fitting techniques to provide hypotheses on the mechanisms of immune response formation and function. The immune system, comprised of the innate and adaptive immune responses, is responsible for protecting the body against invading pathogens, such as viruses, bacteria, or fungi. If an immune response to a secondary pathogen encounter differs from the response when the body first encounters the specific pathogen, this is called immune memory. The mechanisms underlying the memory of immune responses are well understood in the context of adaptive immune responses, but less so for innate immune responses. Stimulation with lipopolysaccharide, a cell wall component of many bacteria, programs innate immune cells, such as macrophages, to be in one of two states, called phenotypes, depending on the strength of the stimulus. Based on their phenotype the macrophages show either a weak or strong inflammatory response upon a secondary lipopolysaccharide encounter of a constant dose. We model the biochemical kinetics of three molecules involved in macrophages responses to lipopolysaccharide. We find that once a macrophage is programed to show a weak inflammatory response this cannot be reverted. Contrarily, a secondary lipopolysaccharide stimulus that is either of a very high dose or applied before the effects of the primary stimulus have waned, can induce a phenotype switch in macrophages initially programed to show strong inflammatory responses. Some pathogens, such as the hepatitis B virus, have developed strategies that hinder an efficient innate immune response. Hepatitis B virus infection is a worldwide pandemic with approximately 257 million chronically infected people. Hepatitis B e antigen is a protein that infected liver cells release into blood and that impairs adaptive immune responses. It is considered a beneficial event in disease progression, and called hepatitis B e antigen clearance, when hepatitis B e antigen becomes indetectable in a patient's blood. We propose mathematical models of interactions between liver cells, the virus, hepatitis B e antigens and hepatitis B e antibodies, which neutralize the antigens. We predict that antibody formation causes antigen clearance and a reactivation of immune responses. We furthermore use the model to quantify the time between antibody formation and antigen clearance and the average number of liver cells killed during that time. We further expand the study of hepatitis B infection, by investigating the kinetics of the virus under an experimental drug administered during a clinical trial. Available drugs rarely induce hepatitis B s antigen clearance, but clinical trials that combined a novel drug, called ARC-520, with the commonly used drug entecavir have shown promising results in reducing hepatitis B s antigen titers in the blood of infected patients. Following the clearance of hepatitis B s antigen, a protein that is released by infected cells and impairs adaptive immunity, the body usually has the capability to control the infection without medication. We develop mathematical models describing the interactions of the drugs, hepatitis B virus, and virus proteins. We fit the model to clinical trial data and predict that ARC-520 alone is responsible for the reduction of hepatitis B s and e antigens, while entecavir is the driving force behind viral reduction.

Antiviral therapy for patients infected with hepatitis B virus is only partially efficient. The field is in high demand for understanding the connections between the virus, immune responses, short-term and long-term drug efficacy and the overall health of the liver. A mathematical model was introduced in 2009 to help elucidate the host-virus dynamics after the start of therapy. The model allows the study of complicated viral patterns observed in HBV patients. In our research, we will analyze this model to determine the biological markers (e.g. liver proliferation, immune responses, and drug efficacy) that determine the different decay patterns. We will also investigate how such markers affect the length of therapy and the amount of liver damage. / Master of Science

Yes / A study was conducted to determine the seroprevalence of chronic hepatitis B virus (HBV) infection among children and their mothers on Kwajalein Atoll in the Marshall Islands two decades after routine vaccination was introduced in the 1990s. Mothers’ knowledge and attitudes towards HBV disease and vaccination were also assessed. Methods: Results of a national seroprevalence survey conducted in 2016–2017 and antenatal records were used to determine the prevalence of HBV seropositivity in children aged 6–8 years and their biological mothers. The associations between demographic, social and vaccination-related factors and seropositivity were explored using Fisher’s exact tests. Results: HBV seroprevalence was 0.3% in children and 6.8% in their mothers (during pregnancy). Coverage of timely HBV vaccination was 90.3% for the birth dose and was significantly associated with factors related to place of residence (P < 0.001), place of birth (P < 0.001) and number of antenatal visits (P < 0.001). Maternal attitudes towards infant vaccination and antenatal screening were largely positive (95.8% and 96.7%, respectively) despite low vaccination rates (20.9%) among mothers. Knowledge levels were low for disease complications, treatment and transmission. Discussion: Prevalence of HBV in children and mothers residing on Kwajalein Atoll in 2016–2017 was lower than the national average for the Marshall Islands. Timely birth dose administration appears to have been effective in preventing mother-to-child transmission of HBV in this setting and should be promoted in remote settings where antiviral therapy is not available. Provision of out-of-cold-chain HBV vaccines should be considered to improve access in remote settings.

Background: In times of limited organs for transplantation, anti-HBc positive organs can be accepted for lung transplantation to increase the number of donors. Transplant recipients should be vaccinated against hepatitis B to prevent HBV infection. However, response after HBV vaccination has only been poorly evaluated in patients with end-stage pulmonary disease. Material/Methods: Anti-HBs titers of 40 anti-HBc negative patients with end-stage pulmonary disease evaluated for lung transplantation were analyzed with the Architect® system (Abbott, Germany). Responders, partial responders, or non-responders after HBV vaccination were defined by anti-HBs titers >100 IU/L, 10–100 IU/L, and <10 IU/L, respectively. Results: There were 34/40 individuals (85%) vaccinated against hepatitis B, and 6 were not vaccinated. Response, partial response, and non-response after vaccination were observed in 10/34 (29.4%), 11/34 (32.4%), and 13/34 (38.2%) of patients, respectively. Response to vaccination did not correlate with sex, pulmonary disease, comorbidities, immunosuppressive therapy, or smoking status. Conclusions: Although 85% of patients evaluated for lung transplantation were vaccinated against hepatitis B, 38.2% did not show an anti-HBs titer >10 IU/L. Thus, anti-HBs titers should be regularly monitored. Nonresponders should be considered for booster vaccinations, alternative vaccination schedules, or prophylactic treatment with a nucleos(t)ide analogue in case of transplantation of an anti-HBc–positive organ.

Η πολυλειτουργική πρωτεΐνη core του ιού της ηπατίτιδας C (HCV) εμπλέκεται στην ανάπτυξη ηπατοκυτταρικού καρκινώματος (HCC) που προκαλείται από τον ιό της ηπατίτιδας C, αλλά ο μηχανισμός με τον οποίο συμβαίνει αυτό δεν είναι κατανοητός. Η ενεργοποίηση του μονοπατιού Wnt/ β-κατενίνη, παίζει ένα σημαντικό ρόλο στην ανάπτυξη ηπατοκυττταρικού καρκίνου, και τροποποιείται από την πρωτεΐνη core του ιού της ηπατίτιδας C. Ο ιός της ηπατίτιδας C χαρακτηρίζεται από εκτεταμένη γενετική ποικιλομορφία και διαφορετικά κλινικά δείγματα διαφέρουν όσον αφορά την μολυσματικότητα τους και την παθογένεια που προκαλούν. Σκοπός αυτής της μελέτης είναι να καθοριστεί ο ρόλος της γενετικής ποικιλομορφίας της πρωτεΐνης HCV core στην ενεργοποίηση του μονοπατιού Wnt/ β-κατενίνη και να μελετηθεί ο μοριακός μηχανισμός με τον οποίο η πρωτεΐνη HCV core ρυθμίζει την ενεργοποίηση αυτή. Η ενεργότητα του μονοπατιού Wnt/β-κατενίνη μελετήθηκε σε HEK 293T και Huh 7.5 κυτταρικές σειρές που εκφράζουν παροδικά τις πρωτεΐνες core των γενοτύπων 1a, 1b, 3a, 4a, 4f και από ένα μοναδικό δείγμα του γενοτύπου 1a που προέρχεται από έναν ασθενή από την Καμπότζη (1aCam). Μελέτες βασισμένες στη μέτρηση ενεργότητας της λουσιφεράσης, Western blot ανάλυση και qPCR, χρησιμοποιήθηκαν για την μέτρηση των επιπέδων έκφρασης γονιδίων και πρωτεϊνών. Βρέθηκε ότι η HCV core πρωτεΐνη ρυθμίζει θετικά την μεσολαβούμενη από τη β-κατενίνη Tcf-εξαρτώμενη ενεργότητα της λουσιφεράσης σε ένα γενοτυπο-εξαρτώμενο τρόπο. Σε συμφωνά με τα αποτελέσματα αυτά βρέθηκε ότι η πρωτεΐνη HCV core σταθεροποίει τα επίπεδα της β-κατενίνης, τόσο σε παροδικά μετασχηματισμένα κύτταρα, όσο και σε κύτταρα που μολύνονται με βακουλοϊούς που εκφράσουν τις πρωτεΐνες core των υποτύπων 4a και 4f. Τέλος, βρέθηκε ότι η πρωτεΐνη HCV core συμβάλει στην θετική ρύθμιση των γονιδίων c-myc, αξίνης και Tbx3, τα οποία είναι καθοδικά γονίδια στόχοι του μονοπατιού Wnt/β-κατενίνη και εμπλέκονται στην ανάπτυξη ηπατοκυτταρικού καρκινώματος. Συμπερασματικά, οι πρωτεΐνες HCV core διαφορετικών γενοτύπων του ιού ρυθμίζουν διαφορετικά το μονοπάτι σηματοδότησης Wnt/β-κατενίνη και η διαφορετική αυτή ρύθμιση μπορεί να σχετίζεται με ικανότητα των διαφόρων γενοτύπων του ιού της ηπατίτιδας C να επάγουν την ανάπτυξη ηπατοκυτταρικού καρκινώματος. / The multifunctional HCV core protein is implicated in the development of hepatocellular carcinoma (HCC) caused by HCV infection, but the underlying mechanism is not fully understood. Activation of the Wnt/ β-catenin pathway plays a major role in HCC and is modulated by the HCV core protein. HCV is characterized by extensive genetic diversity and different clinical isolates do vary in their infectivity and pathogenesis mainly due to variations in the structure/function relationships of individual viral proteins. The aim of this study is to determine the possible influence of genetic variability in HCV core protein in enhancing the Wnt/ β-catenin signaling activity and to elucidate the molecular mechanisms by which HCV core modulates activation of β-catenin. The Wnt/β-catenin activity was investigated in transiently transfected HEK 293T and Huh 7.5 cell lines transiently expressing HCV core proteins from HCV genotypes 1a, 1b, 4a, 4f and from a unique isolate of genotype 1a obtained from a Cambodian patient (1aCam). Luciferase-based reporter assay, Western blot, and qPCR, were used to measure gene and protein expression levels. We found that, HCV core protein upregulates β-catenin-mediated Tcf-dependent luciferase activity in a genotype specific manner. Consistent to these findings, HCV core stabilizes β-catenin levels. Finally, we showed that HCV core contributes to the upregulation of Tbx3 gene expression, a downstream target gene of Wnt/ β-catenin pathway contributing to HCC development. In conclusion, HCV core protein from different genotypes appears to differentially regulate the Wnt/β-catenin signaling pathway and this finding may contribute to different potential of HCV genotypes to induce HCC.

Tc17 cells and the semi-invariant human mucosal associated invariant T (MAIT) cells are important CD8+ tissue-homing cell populations. Both are characterized by high expression of CD161 (++) and type-17 differentiation, yet their origins and relationships remain poorly defined. By transcriptional and functional analyses it is demonstrated that a pool of polyclonal, pre-committed type-17 CD161++CD8αβ+ T cells exists in cord blood, from which a prominent MAIT cell (TCR Vα7.2+/Vβ2 or 13.2) population emerges post-natally. During this expansion, CD8αα T-cells appear exclusively within CD161++CD8+/MAIT subset, sharing cytokine production (IL17, IL-22 and IFN-γ), chemokine-receptor expression (CCR2, CCR6 and CXCR6), TCR-usage and transcriptional profiles with their CD161++CD8αβ+ counterparts. These data demonstrate the origin and differentiation pathway of MAIT cells from a naïve type-17 pre-committed CD161++CD8+ T cell pool and the distinct phenotype and function of CD8αα cells in man. The CD161++CD8αβ and CD8αα T cell subsets are reduced in the peripheral circulation in chronic hepatitis B and C and are enriched in the liver in chronic hepatitis C. Their potential role in immunity to chronic viral hepatitis B and C is demonstrated by their expression of activation/exhaustion markers CD69, CD25, HLA-DR and PD-1. In addition a substantial distinct CD161-CD8β^low population is demonstrated in chronic hepatitis B, co-characterised by a CD28^low, HLA-DR^high phenotype and high expression of IFN-γ, with important implications for the development of immunotherapy and vaccination.

Student Number : 9906382M MSc (Med) dissertation - Faculty of Health Sciences / The G1862T mutation in the bulge of the RNA encapsidation signal, in the precore region of hepatitis B virus, results in reduced expression of HBeAg and accumulation of the HBeAg precursor in the endoplasmic reticulum (ER)/Golgi apparatus of the cell. This accumulation can disturb the functioning of the ER and lead to the ER stress response that can affect various cellular pathways, in turn affecting cell viability. The aim of this study was to determine whether apoptosis or necrosis occurred when cultured Huh7 cells were transfected with a plasmid expressing the G1862T mutation. Plasmid constructs, with and without the G1862T mutation, were used to transfect cells. To differentiate between necrosis and apoptosis cells were stained with propidium iodide or YO-PRO-1®, respectively. These were analyzed quantitatively using flow cytometry and qualitatively using confocal microscopy. Confocal microscopy, using monoclonal anti- HBe and the Hoechst stain, was performed to ensure that apoptosis was present as a result of the accumulation of the G1862T mutant HBeAg precursor. Caspase profiling was carried out using a fluorogenic-based assay. When cells were transfected with wild-type plasmid, necrosis predominated over apoptosis. Apoptosis predominated when the cells were transfected with the G1862T mutant plasmid. The highest levels of apoptosis occurred at 72 hours post-transfection. Confocal microscopy revealed the co-localization of aggregates of mutant HBeAg precursor with apoptotic nuclei. Transfection with G1862T mutant plasmids resulted in significant differences in the expression of caspase 3, 8, and 9 relative to the wild-type, at 48 and 72 hours post-transfection. The accumulation of the G1862T mutant HBeAg precursor, in the ER/ Golgi compartment, leads to apoptosis and affects the levels of caspase expression.

Estudo observacional transversal que teve como objetivos caracterizar os pacientes com diabetes mellitus segundo as variáveis demográficas e clínicas; estimar a prevalência de infecção pelo vírus da hepatite B e C e a cobertura vacinal contra hepatite B em pacientes com diabetes mellitus e identificar potenciais fatores de risco relacionados. A amostra de conveniência foi constituída de 255 pacientes com diabetes mellitus que compareceram à consulta médica nos ambulatórios de Endocrinologia e de Clínica Médica Integrado de Unidade Distrital de Saúde de Ribeirão Preto-SP, no período de julho a dezembro de 2014. As variáveis demográficas selecionadas foram sexo, idade e escolaridade e, as clínicas o uso de insulina, monitoramento da glicemia capilar, história de intervenções médicas, cirúrgicas, diagnósticas e terapêuticas e situações e comportamentos de risco para hepatite B e C. Os marcadores sorológicos investigados foram HBsAg, Anti-HBc IgG, Anti-HBc IgM, Anti-HBs e Anti-HCV. Considerou-se vacinação completa três ou mais doses da vacina contra hepatite B registrada. Para a coleta de dados utilizou-se um questionário, consulta ao registro de vacinação no Sistema Informatizado de Gestão em Saúde da Secretaria Municipal de Saúde e coleta de sangue venoso. Os dados foram apresentados por meio de estatística descritiva. A análise univariada das possíveis associações entre as variáveis demográficas e clínicas e os desfechos infecção pelo vírus da hepatite B e C e cobertura vacinal contra hepatite B, foi determinada pelos testes de Qui-quadrado corrigido por Pearson ou Teste exato de Fisher bicaudal e Wilcoxon para amostras não pareadas. Para a análise multivariada, foi construído um modelo de regressão logística onde foram incluídas as variáveis que exibiram p<0,2 na análise univariada. Valores de \'p\' inferiores a 5% foram considerados significativos. Os resultados mostraram que 16,8% dos pacientes apresentaram marcador Anti-HBc total reagente, 8,2% Anti-HBs isolado e 75% foram não reagentes para todos os marcadores de hepatite B. Nenhum caso de HBsAg reagente foi encontrado na amostra estudada. Quanto à infecção pelo vírus da hepatite C, 3,3% dos pacientes apresentaram marcador anti-HCV reagente. A prevalência de infecção pelo vírus da hepatite B (Anti-HBc reagente) em pacientes com diabetes mellitus foi de 16,8%, superior à nacional e mostrou-se diretamente associado ao tempo da doença. A prevalência de infecção pelo vírus da hepatite C (Anti-HCV reagente) foi de 3,3%, superior à nacional, mas não teve associação com as variáveis demográficas e clínicas investigadas. A cobertura vacinal contra hepatite B mostrou-se baixa (15%) em pacientes com diabetes mellitus evidenciando a sua vulnerabilidade a essa doença grave e potencialmente fatal. Maior escolaridade e o trabalho na área da saúde foram associados à melhor cobertura vacinal. Estes resultados fornecem subsídios importantes para a avaliação da prática clínica dos enfermeiros na atenção primaria à saúde para a prestação de cuidados relacionados à cobertura vacinal a pessoas com diabetes mellitus. Assim, esforços devem ser empenhados pelos profissionais e serviços de saúde para enfrentar o desafio de prover ampla cobertura vacinal a essa população, garantindo a prevenção da infecção pelo vírus da hepatite B e C / A cross-sectional observational study aimed at characterizing patients with diabetes mellitus according to demographic and clinical variables; to estimate the prevalence of hepatitis B and C virus infection and vaccine coverage in patients with diabetes mellitus and to identify potential related risk factors. The convenience sample consisted of 255 patients with diabetes mellitus who attended the medical consultation in the outpatient clinics of Endocrinology and Integrated Medical Clinic of the District Health Unit of Ribeirão Preto-SP, from July to December 2014. The selected demographic variables the use of insulin, capillary blood glucose monitoring, history of medical, surgical, diagnostic and therapeutic interventions and risky situations and behaviors for hepatitis B and C. The serological markers investigated were HBsAg, Anti -HBc IgG, Anti-HBc IgM, Anti-HBs and Anti-HCV. Three or more doses of the registered hepatitis B vaccine were considered complete vaccination. To collect data, a questionnaire was used, consulting the vaccination record of the Health Management Computerized System of Health of the Municipal Health Department and venous blood collection. The data were presented by means of descriptive statistics. Univariate analysis of possible associations between demographic and clinical variables and outcomes of hepatitis B and C virus infection and vaccine coverage against hepatitis B was determined by the Pearson-corrected chi-square test or Wilcoxon\'s exact Fisher\'s test for Unpaired samples. For the multivariate analysis, a logistic regression model was constructed in which variables that exhibited p <0.2 were included in the univariate analysis. Values of \'p\' below 5% were considered significant. The results showed that 16.8% of the patients presented total anti-HBc marker reagent, 8.2% Anti-HBs alone and 75% were non-reactive for all hepatitis B markers. No case of HBsAg reagent was found in the sample studied. Regarding hepatitis C virus infection, 3.3% of the patients presented anti-HCV marker reagent. The prevalence of hepatitis B virus (Anti-HBc reagent) in patients with diabetes mellitus was 16.8% higher than the national level and was directly associated with the time of diabetes mellitus. The prevalence of hepatitis C virus infection (Anti-HCV reagent) was 3.3%, higher than the national level, but had no association with the demographic and clinical variables investigated. Hepatitis B vaccination coverage was shown to be low (15%) in patients with diabetes mellitus evidencing their vulnerability to this serious and potentially fatal disease. Higher schooling and work in the health area were associated with better vaccine coverage. These results provide important insights for the evaluation of nurses\' clinical practice in primary health care for care related to vaccination coverage for people with diabetes mellitus. Thus, efforts must be made by health professionals and services to meet the challenge of providing ample vaccination coverage to this population, ensuring the prevention of hepatitis B and C virus infection