Mixed Infections Unravel Novel HCV Inter-Genotypic Recombinant Forms within the Conserved IRES Region.

Hepatitis C virus (HCV) remains a significant global health challenge, affecting millions of people worldwide, with chronic infection a persistent threat. Despite the advent of direct-acting antivirals (DAAs), challenges in diagnosis and treatment remain, compounded by the lack of an effective vaccine. The HCV genome, characterized by high genetic variability, consists of eight distinct genotypes and over ninety subtypes, underscoring the complex dynamics of the virus within infected individuals. This study delves into the intriguing realm of HCV genetic diversity, specifically exploring the phenomenon of mixed infections and the subsequent detection of recombinant forms within the conserved internal ribosome entry site (IRES) region. Previous studies have identified recombination as a rare event in HCV. However, our findings challenge this notion by providing the first evidence of 1a/3a (and vice versa) inter-genotypic recombination within the conserved IRES region. Utilizing advanced sequencing methods, such as deep sequencing and molecular cloning, our study reveals mixed infections involving genotypes 1a and 3a. This comprehensive approach not only confirmed the presence of mixed infections, but also identified the existence of recombinant forms not previously seen in the IRES region. The recombinant sequences, although present as low-frequency variants, open new avenues for understanding HCV evolution and adaptation.

Nitrofurantoin-induced liver injury: long-term follow-up in two prospective DILI registries.

Nitrofurantoin is a synthetic antibiotic that is recommended as first-choice treatment for uncomplicated urinary tract infections. The prescription of this drug has increased dramatically, especially in Latin American countries. We described the demographics, clinical characteristics, biochemical features, and outcome of nitrofurantoin-induced liver injury. We analyzed 23 cases from the Latin American DILI Network (LATINDILI) and the Spanish DILI Registry. Causality was assessed with the RUCAM and RECAM scale. Of the 23 DILI cases included in our series, 96% patients were women, and the mean age of the whole cohort was 61 years. The median time of drug exposure was 175 days (interquartile range [IQR] 96-760), with 11 patients who were prescribed nitrofurantoin for more than six months. Hepatocellular damage was the most frequent pattern of liver injury (83%), and nearly half of the patients had an asymptomatic presentation (52%). Neither death nor liver transplantation was documented in this series. Overall, 65% of the patients (n = 15) presented with positive autoantibody titres. The median time to resolution was 81 days (IQR 57-141), and 15 patients (83%) recovered within six months. Five patients (22%) developed nitrofurantoin-induced autoimmune-like hepatitis (NI-AILH), of whom two were characterized by a persistent increase in transaminases that required immunosuppressive treatment to achieve normalization of liver enzymes. Clinicians who prescribe nitrofurantoin should be aware that patients who had taken nitrofurantoin for a long term may be at risk of developing nitrofurantoin-induced autoimmune-like hepatitis.

Implementation of a re-linkage to care strategy in patients with chronic hepatitis C who were lost to follow-up in Latin America.

To achieve WHO's goal of eliminating hepatitis C virus (HCV), innovative strategies must be designed to diagnose and treat more patients. Therefore, we aimed to describe an implementation strategy to identify patients with HCV who were lost to follow-up (LTFU) and offer them re-linkage to HCV care. We conducted an implementation study utilizing a strategy to contact patients with HCV who were not under regular follow-up in 13 countries from Latin America. Patients with HCV were identified by the international classification of diseases (ICD-9/10) or equivalent. Medical records were then reviewed to confirm the diagnosis of chronic HCV infection defined by anti-HCV+ and detectable HCV-RNA. Identified patients who were not under follow-up by a liver specialist were contacted by telephone or email, and offered a medical reevaluation. A total of 10,364 patients were classified to have HCV. After reviewing their medical charts, 1349 (13%) had undetectable HCV-RNA or were wrongly coded. Overall, 9015 (86.9%) individuals were identified with chronic HCV infection. A total of 5096 (56.5%) patients were under routine HCV care and 3919 (43.5%) had been LTFU. We were able to contact 1617 (41.3%) of the 3919 patients who were LTFU at the primary medical institution, of which 427 (26.4%) were cured at a different institutions or were dead. Of the remaining patients, 906 (76.1%) were candidates for retrieval. In our cohort, about one out of four patients with chronic HCV who were LTFU were candidates to receive treatment. This strategy has the potential to be effective, accessible and significantly impacts on the HCV care cascade.

Hepatotoxicity Induced by Biological Agents: Clinical Features and Current Controversies.

Novel biological agents including cytokines and recombinant fusion proteins are increasingly prescribed for cancer, rheumatologic, autoimmune, and inflammatory diseases, and are currently being evaluated in hepatocellular carcinoma (HCC). They are classified by their mechanism of action and include tumor necrosis factor-alpha (TNF-α) antagonists, T cell mediated antitumor inhibitors, interleukin receptor antagonists, and immune checkpoint inhibitors (ICIs). Some ICIs cause frequent hepatotoxicity with a variable clinical, biochemical, and serological presentation, especially in patients receiving another immunomodulatory agent. Half of the cases of liver damage induced by biological agents spontaneously regress after drug withdrawal, but the others require steroid therapy. Unfortunately, there are no widely accepted recommendation for the use of corticosteroids in these patients, even though international cancer societies have their own guidelines. Differentiating drug-induced autoimmune hepatitis (DIAIH) from classic AIH is challenging for pathologists, but liver biopsy is valuable, particularly in cases with unclear clinical presentation. Interesting, novel histological patterns have been described in liver damage induced by these agents (i.e., endothelitis, ring granuloma and secundary sclerosing cholangitis associated with lymphocytic infiltration of cytotoxic CD8+T cells). Here, we describe the clinical and biochemical characteristics of patients with hepatotoxicity induced by TNF-α antagonists and ICIs. Controversial issues involved in the administration of corticosteroid therapy, and hepatitis B virus (HBV) reactivation induced by immunosuppressive therapy are also discussed.

Impact of Public Health Policies on Alcohol-Associated Liver Disease in Latin America: An Ecological Multinational Study.

BACKGROUND AND AIMS: Alcohol-associated liver disease (ALD) is the leading cause of liver-related mortality in Latin America, yet the impact of public health policies (PHP) on liver disease is unknown. We aimed to assess the association between alcohol PHP and deaths due to ALD in Latin American countries. APPROACH AND RESULTS: We performed an ecological multinational study including 20 countries in Latin America (628,466,088 inhabitants). We obtained country-level sociodemographic information from the World Bank Open Data source. Alcohol-related PHP data for countries were obtained from the World Health Organization Global Information System of Alcohol and Health. We constructed generalized linear models to assess the association between the number of PHP (in 2010) and health outcomes (in 2016). In Latin America, the prevalence of obesity was 27% and 26.1% among male and female populations, respectively. The estimated alcohol per capita consumption among the population at 15 years old or older was 6.8 L of pure alcohol (5.6 recorded and 1.2 unrecorded). The overall prevalence of alcohol use disorders (AUD) was 4.9%. ALD was the main cause of cirrhosis in 64.7% of male and 40.0% of female populations. A total of 19 (95%) countries have at least one alcohol-related PHP on alcohol. The most frequent PHP were limiting drinking age (95%), tax regulations (90%), drunk-driving policies and countermeasures (90%), and government monitoring systems and community support (90%). A higher number of PHP was associated with a lower ALD mortality (PR, 0.76; 95% CI, 0.61-0.93; P = 0.009), lower AUD prevalence (PR, 0.80; 95% CI, 0.65-0.99; P = 0.045), and lower alcohol-attributable road traffic deaths (PR, 0.81; 95% CI, 0.65-1.00; P = 0.051). CONCLUSIONS: Our study indicates that in Latin America, countries with higher number of PHP have lower mortality due to ALD, lower prevalence of AUD, and lower alcohol-attributable road traffic mortality.

Drug-Induced Vanishing Bile Duct Syndrome: From Pathogenesis to Diagnosis and Therapeutics.

The most concerned issue in the context of drug/herb-induced chronic cholestasis is vanishing bile duct syndrome. The progressive destruction of intrahepatic bile ducts leading to ductopenia is usually not dose dependent, and has a delayed onset that should be suspected when abnormal serum cholestasis enzyme levels persist despite drug withdrawal. Immune-mediated cholangiocyte injury, direct cholangiocyte damage by drugs or their metabolites once in bile, and sustained exposure to toxic bile salts when biliary epithelium protective defenses are impaired are the main mechanisms of cholangiolar damage. Current therapeutic alternatives are scarce and have not shown consistent beneficial effects so far. This review will summarize the current literature on the main diagnostic tools of ductopenia and its histological features, and the differential diagnostic with other ductopenic diseases. In addition, pathomechanisms will be addressed, as well as the connection between them and the supportive and curative strategies for ductopenia management.

Resistance-associated substitutions and response to treatment in a chronic hepatitis C virus infected-patient: an unusual virological response case report.

BACKGROUND: Direct-Acting agents (DAAs) target and inhibit essential viral replication proteins. They have revolutionized the treatment of Hepatitis C virus (HCV) infection reaching high levels of sustained virologic response. However, the detection of basal resistance-associated substitutions (RASs) to DAAs in naïve patients could be important in predicting the treatment outcome in some patients exhibiting failures to DAA-based therapies. Therefore, the aim of this work was to evaluate the presence of RASs as minority variants within intra-host viral populations, and assess their relationship to response to therapy on a multiple times relapser patient infected chronically with HCV. CASE PRESENTATION: A male HCV infected-patient with a genotype 1a strain was evaluated. He had previously not responded to dual therapy (pegylated interferon-α plus ribavirin) and was going to start a direct-acting agent-based therapy (DAAs). He showed no significant liver fibrosis (F0). Viral RNA was extracted from serum samples taken prior and after therapy with DAAs (sofosbubir/ledipasvir/ribavirin). NS5A and NS5B genomic regions were PCR-amplified and the amplicons were sequenced using Sanger and next-generation sequencing (NGS) approaches. RASs were searched in in-silico translated sequences for all DAAs available and their frequencies were determined for those detected by NGS technology. Sanger sequencing did not reveal the presence of RASs in the consensus sequence neither before nor after the DAA treatment. However, several RASs were found at low frequencies, both before as well as after DAA treatment. RASs found as minority variants (particularly substitutions in position 93 within NS5A region) seem to have increased their frequency after DAA pressure. Nevertheless, these RASs did not become dominant and the patient still relapsed, despite perfect adherence to treatment and having no other complications beyond the infection (no significant fibrosis, no drug abuse). CONCLUSIONS: This report shows that some patients might relapse after a DAA-based therapy even when RASs (pre- and post-treatment) are detected in very low frequencies (< 1%) within intra-host viral populations. Increased awareness of this association may improve detection and guide towards a personalized HCV treatment, directly improving the outcome in hard-to-treat patients.

Serious liver injury induced by Nimesulide: an international collaborative study.

Nimesulide is a non-steroidal anti-inflammatory drug still marketed in many countries. We aim to analyze the clinical phenotype, outcome, and histological features of nimesulide-induced liver injury (nimesulide-DILI). We analyzed 57 cases recruited from the Spanish and Latin American DILI registries. Causality was assessed by the RUCAM scale. Mean age of the whole case series was 59 years (86% women) with a median time to onset of 40 days. A total of 46 patients (81%) were jaundiced. Nimesulide-DILI pattern was hepatocellular in 38 (67%), mixed in 12 (21%), and cholestatic in 7 (12%) cases. Transaminases were elevated with a mean of nearly 20-fold the upper limit of normality (ULN), while alkaline phosphatase showed a twofold mean elevation above ULN. Total bilirubin showed a mean elevation of 13-fold the ULN. Liver histology was obtained in 14 cases (25%), most of them with a hepatocellular pattern. Median time to recovery was 60 days. Overall, 12 patients (21%) developed acute liver failure (ALF), five (8.8%) died, three underwent liver transplantation (5.3%), and the remaining four resolved. Latency was ≤ 15 days in 12 patients (21%) and one patient developed ALF within 7 days from treatment initiation. Increased total bilirubin and aspartate transaminase levels were independently associated with the development of ALF. In summary, nimesulide-DILI affects mainly women and presents typically with a hepatocellular pattern. It is associated with ALF and death in a high proportion of patients. Shorter (≤ 15 days) duration of therapy does not prevent serious nimesulide hepatotoxicity, making its risk/benefit ratio clearly unfavorable.

Drug-induced liver injury: A management position paper from the Latin American Association for Study of the liver.

Idiosyncratic drug-induced liver injury (DILI) caused by xenobiotics (drugs, herbals and dietary supplements) is an uncommon cause of liver disease presenting with a wide range of phenotypes and disease severity, acute hepatitis mimicking viral hepatitis to autoimmune hepatitis, steatosis, fibrosis or rare chronic vascular syndromes. Disease severity ranges from asymptomatic liver test abnormalities to acute liver failure. DILI has been traditionally classified in predictable or intrinsic (dose-related) or unpredictable (not dose-related) mechanisms. Few prospective studies are assessing the real prevalence and incidence of hepatotoxicity in the general population. DILI registries represent useful networks used for the study of liver toxicity, aimed at improving the understanding of causes, phenotypes, natural history, and standardized definitions of hepatotoxicity. Although most of the registries do not carry out population-based studies, they may provide important data related to the prevalence of DILI, and also may be useful to compare features from different countries. With the support of the Spanish Registry of Hepatotoxicity, our Latin American Registry (LATINDILI) was created in 2011, and more than 350 DILI patients have been recruited to date. This position paper describes the more frequent drugs and herbs-induced DILI in Latin America, mainly focusing on several features of responsible medicaments. Also, we highlighted the most critical points on the management of hepatotoxicity in general and those based on findings from our Latin American experience in particular.

Latin American Association for the study of the liver (ALEH) practice guidance for the diagnosis and treatment of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) currently represents an epidemic worldwide. NAFLD is the most frequently diagnosed chronic liver disease, affecting 20-30% of the general population. Furthermore, its prevalence is predicted to increase exponentially in the next decades, concomitantly with the global epidemic of obesity, type 2 diabetes mellitus (T2DM), and sedentary lifestyle. NAFLD is a clinical syndrome that encompasses a wide spectrum of associated diseases and hepatic complications such as hepatocellular carcinoma (HCC). Moreover, this disease is believed to become the main indication for liver transplantation in the near future. Since NAFLD management represents a growing challenge for primary care physicians, the Asociación Latinoamericana para el Estudio del Hígado (ALEH) has decided to organize this Practice Guidance for the Diagnosis and Treatment of Non-Alcoholic Fatty Liver Disease, written by Latin-American specialists in different clinical areas, and destined to general practitioners, internal medicine specialists, endocrinologists, diabetologists, gastroenterologists, and hepatologists. The main purpose of this document is to improve patient care and awareness of NAFLD. The information provided in this guidance may also be useful in assisting stakeholders in the decision-making process related to NAFLD. Since new evidence is constantly emerging on different aspects of the disease, updates to this guideline will be required in future.

Decompensated cirrhosis and liver transplantation negatively impact in DAA treatment response: Real-world experience from HCV-LALREAN cohort.

INTRODUCTION: Although the effectiveness of direct-acting antivirals (DAAs) for the treatment of chronic hepatitis C virus (HCV) has been reported in real-world settings, predictive factors of treatment failure are lacking. Therefore, we sought to explore the baseline predictors of treatment response to DAAs. METHODS: This was a prospective multicenter cohort study from the Latin American Liver Research Educational and Awareness Network (LALREAN) including patients who received DAA treatment from May 2016 to April 2019. A multivariate logistic regression model was conducted to identify variables associated with unachieved sustained virological response (SVR), defined as treatment failure (odds ratios [OR] and 95% confidence intervals [CIs]). RESULTS: From 2167 patients (55.2% with cirrhosis) who initiated DAA therapy, 89.4% completed a full-course treatment (n = 1938). Median treatment duration was 12 weeks, and 50% received ribavirin. Definitive suspension due to intolerance or other causes was observed in only 1.0% cases (n = 20). Overall non-SVR12 was 4.5% (95% CI, 3.5-5.7). There were no significant differences in treatment failure according to HCV genotypes and the degree of fibrosis. Independently associated variables with DAA failure were liver function impairment according to the Child-Pugh score B OR, 2.09 (P = .06), Child-Pugh C OR, 11.7 (P < .0001); and liver transplant (LT) recipient OR, 3.75 (P = .01). CONCLUSION: In this real-life setting, higher DAA treatment failure rates were observed in patients with decompensated cirrhosis and in LT recipients. These predictive baseline factors should be addressed to individualize the appropriate time-point of DAA treatment (NCT03775798; www. CLINICALTRIALS: gov).

Translating new knowledge on drug-induced liver injury into clinical practice.

Drug-induced liver injury (DILI) is one of the main reasons for drug withdrawal from the market, and a cause of worldwide morbidity. Although several issues on DILI are still unsolved, there have been significant advances in new definitions and diagnosis tools. DILI is the result of a complex interaction between genetic and environmental factors, and constitutes an expanding area of investigation. DILI can mimic virtually all known hepatopathies, including vascular disorders and liver tumours. As part of this broad spectrum of clinical presentations, DILI severity ranges from asymptomatic elevations of aminotransferases to acute liver failure. Although biomarkers are emerging as valuable diagnostic tools, they are not available in clinical practice. Accurate DILI diagnosis is a challenging issue, particularly the establishing of causal relationships with the culprit agent and the exclusion of competing causes of liver injury. Given that the understanding of the mechanisms inducing DILI is growing, and both DILI causality assessment scales and the performance of international DILI networks have been improved, hepatotoxicity may be recognised earlier in clinical practice. In this review, advances and results obtained by DILI registries around the world, case characterisations, particularly those relevant to newer definitions in DILI, and the behaviour of chronic liver disease induced by drugs will be updated. In addition, recently published data on herbal and dietary supplements and new predictive scores for acute liver failure assessment will also be discussed.

Enfermedad de Wilson: presentación hepática y revisión bibliográfica / Wilson's disease: liver presentation and literature review / Doença de Wilson: apresentação hepática e revisão de literatura

Resumen: La Enfermedad de Wilson es un trastorno genético raro que puede presentarse a cualquier edad y se caracteriza por el depósito de cobre a nivel hepático y cerebral. La afectación hepática abarca desde formas asintomática hasta falla hepática fulminante o cirrosis. Su diagnóstico precoz tiene implicancias pronósticas ya que el tratamiento puede lograr un balance negativo de cobre, permitir el control sintomático y prevenir la progresión de la enfermedad. Se presenta el caso de un hombre de 27 años, con dolor abdominal, en el que se hizo el diagnóstico de Enfermedad de Wilson a partir de una hipertransaminasemia leve. Los hallazgos que orientaron al diagnóstico fueron una cupruria aumentada por inducción con D-penicilamina y una cuantificación de cobre en tejido hepático seco elevada. Con un estadio de fibrosis leve, se comenzó tratamiento con D-penicilamina con buena tolerancia y la normalización de las alteraciones bioquímicas.

Abstract: Wilson's disease is a rare genetic disorder that can occur at any age and is characterized by copper deposition in the liver and brain. Liver involvement ranges from asymptomatic forms to fulminant hepatic failure or cirrhosis. Its early diagnosis has prognostic implications since the treatment can achieve a negative copper balance, allow symptomatic control and prevent the progression of the disease. We present the case of a 27-year-old man with abdominal pain, who was diagnosed with Wilson's disease from mild hypertransaminasemia. The findings that led to the diagnosis were an increased cupruria by induction with D-penicillamine and a quantification of copper in elevated dry liver tissue. With a stage of mild fibrosis, treatment with D-penicillamine was started with good tolerance and normalization of biochemical alterations.

Resumo: Doença de Wilson é uma doença genética rara que pode ocorrer em qualquer idade e é caracterizada pela deposição de cobre no fígado e no cérebro. O envolvimento do fígado varia de formas assintomáticas a insuficiência hepática fulminante ou cirrose. Seu diagnóstico precoce tem implicações prognósticas, uma vez que o tratamento pode alcançar um balanço negativo do cobre, permitir o controle sintomático e prevenir a progressão da doença. Apresentamos o caso de um homem de 27 anos com dor abdominal, diagnosticado com doença de Wilson de hipertransaminasemia leve. Os achados que levaram ao diagnóstico foram aumento da cuprúria por indução com D-penicilamina e quantificação de cobre em tecido hepático seco elevado. Com uma fase de fibrose leve, o tratamento com D-penicilamina foi iniciado com boa tolerância e normalização das alterações bioquímicas.

Assessment of Serious Acute and Chronic Idiosyncratic Drug-Induced Liver Injury in Clinical Practice.

Drug-induced liver injury (DILI) is the leading cause of acute liver failure (ALF) in developed countries. The extremely variable phenotype of DILI, both in presentation and in severity, is one of the distinctive characteristics of the disease and one of the major challenges that hepatologists face when assessing hepatotoxicity cases. A new Hy's law that more accurately predicts the risk of ALF related to DILI has been proposed and validated. Other prognostic scoring algorithms for the early identification of DILI patients who may go on to develop ALF have been developed as it is of most clinical relevance to stratify patients for closer monitoring. Recent data indicate that acute DILI often presents a more prolonged resolution or evolves into chronicity at a higher frequency than other forms of acute liver injury. Risk factors for chronicity, specific phenotypes, and histological features are discussed in this study. Biomarkers to predict DILI outcome are in need.

Treatment with direct-acting antivirals for HCV decreases but does not eliminate the risk of hepatocellular carcinoma.

BACKGROUND & AIMS: Data from Europe and North America have been published regarding the risk of developing hepatocellular carcinoma (HCC) after treatment with direct antiviral agents (DAA). We proposed to evaluate cumulative incidence and associated risk factors for de novo HCC. METHODS: This was a prospective multicentre cohort study from Latin America including 1400 F1-F4-treated patients with DAAs (F3-F4 n = 1017). Cox proportional regression models (hazard ratios, HR and 95% CI) were used to evaluate independent associated variables with HCC. Further adjustment with competing risk regression and propensity score matching was carried out. RESULTS: During a median follow-up of 16 months (IQR 8.9-23.4 months) since DAAs initiation, overall cumulative incidence of HCC was 0.02 (CI 0.01; 0.03) at 12 months and 0.04 (CI 0.03; 0.06) at 24 months. Cumulative incidence of HCC in cirrhotic patients (n = 784) was 0.03 (CI 0.02-0.05) at 12 months and 0.06 (CI 0.04-0.08) at 24 months of follow-up. Failure to achieve SVR was independently associated with de novo HCC with a HR of 4.9 (CI 1.44; 17.32), after adjusting for diabetes mellitus, previous interferon non-responder, Child-Pugh and clinically significant portal hypertension. SVR presented an overall relative risk reduction for de novo HCC of 73% (CI 15%-91%), 17 patients were needed to be treated to prevent one case of de novo HCC in this cohort. CONCLUSIONS: Achieving SVR with DAA regimens was associated with a significant risk reduction in HCC. However, this risk remained high in patients with advanced fibrosis, thus demanding continuous surveillance strategies in this population.

Pretreatment Hepatitis C Virus NS5A/NS5B Resistance-Associated Substitutions in Genotype 1 Uruguayan Infected Patients.

Hepatitis C Virus (HCV) infection treatment has dramatically changed with the advent of direct-acting antiviral agents (DAAs). However, the efficacy of DAAs can be attenuated by the presence of resistance-associated substitutions (RASs) before and after treatment. Indeed, RASs detected in DAA treatment-naïve HCV-infected patients could be useful for clinical management and outcome prediction. Although the frequency of naturally occurring HCV NS5A and NS5B RASs has been addressed in many countries, there are only a few reports on their prevalence in the South American region. The aim of this study was to investigate the presence of RASs to NS5A and NS5B inhibitors in a DAA treatment naïve cohort of Uruguayan patients infected with chronic hepatitis C and compare them with reports from other South American countries. Here, we found that naturally occurring substitutions conferring resistance to NS5A and NS5B inhibitors were present in 8% and 19.2%, respectively, of treatment-naïve HCV genotype 1 infected patients. Importantly, the baseline substitutions in NS5A and NS5B herein identified differ from the studies previously reported in Brazil. Furthermore, Uruguayan strains subtype 1a clustered within all major world clades, showing that HCV variants currently circulating in this country are characterized by a remarkable genetic diversity.

IL28B gene polymorphism rs12979860, but not rs8099917, contributes to the occurrence of chronic HCV infection in Uruguayan patients.

BACKGROUND: Host single-nucleotide polymorphisms (SNPs) near the interleukin 28B (IL28B) locus are associated with sustained virological response to antiviral therapy and with spontaneous Hepatitis C Virus (HCV) clearance. Prevalence of these SNPs varies depending on ethnicity. The impact of IL28B SNPs in HCV-infected patients is currently unknown in Uruguay. Therefore, the aim of this study was to evaluate and compare the distribution of polymorphisms in the IL28B gene (rs12979860 and rs8099917) among HCV-infected patients and healthy individuals in Uruguay and thus assess their possible association with the establishment of HCV infection. METHODS: DNA was recovered from 92 non-infected individuals and 78 HCV-infected patients and SNPs were determined by RFLP and allelic discrimination by real-time PCR. RESULTS: The distribution of rs12979860 genotypes for the infected population was 29.5%-CC, 47.4%-CT and 23.1%-TT and for the control group 45.7%, 42.4% and 11.9%, respectively. Prevalence in both infected and uninfected individuals is similar to that reported in other countries with admixed populations. The distribution of rs8099917 genotypes for the infected population was 57.7%-TT, 27.2%-TG and 14.1%-GG and for the control group 60.9%, 33.7% and 5.4%, respectively. The comparison of rs12979860 genotype distribution between the two populations evidenced a higher prevalence of the favourable genotype (CC) in the uninfected control group (p < 0.05). Additionally, results generated using logistic regression analysis show that individuals carrying rs12979860-TT or CT genotypes have a higher likelihood of developing chronic hepatitis upon infection with HCV, when compared to CC carriers, considering rs8099917 genotype as constant. CONCLUSION: Patients with HCV infection have a statistically significant lower prevalence of the favourable rs12979860 genotype when compared to uninfected individuals; therefore we can establish that only IL28B rs12979860-CT and TT genotypes seem to contribute to the occurrence of chronic HCV infection in the cohort of Uruguayan population studied. Considering that a trend towards a higher frequency of "good" response genotypes was observed in responder patients, we believe that IL28B rs12979860 genotyping could be a useful tool for predicting different therapies outcome, including in the DAA era.