Persistence of hepatitis C virus during and after otherwise clinically successful treatment of chronic hepatitis C with standard pegylated interferon α-2b and ribavirin therapy

Hepatitis C virus serologic relapse after treatment with direct-acting antivirals is dependent on viral RNA levels in peripheral blood mononuclear cells and the grade of liver cirrhosis

The disappearance of hepatitis C virus (HCV) from serum and tissues for 12 weeks after the end of treatment (EOT) with direct-acting antivirals (DAAs) is known as a "sustained virologic response" (SVR) and occurs more frequently in non-cirrhotic patients than in cirrhotic patients. In this study, we evaluated the outcome of HCV treatment with sofosbuvir (SOF) plus ledipasvir (LDV) at both EOT and 12 weeks after EOT in patients with and without hepatic cirrhosis to address the relationship of serologic relapse to persistent infection of PBMCs and the frequency of hepatic encephalopathy and hepatocellular carcinoma (HCC) after treatment. Seventy-five patients with post-HCV liver cirrhosis were assigned to one of three groups (A, B, and C), each of which included 25 patients and corresponded to the patients' Child-Turcotte-Pugh (CTP) classification. All of the patients received a daily dose of SOF (400 mg) plus LDV (90 mg) for 24 weeks and were tested using HCV single-strand reverse transcription (SRT) and PCR analysis of PBMCs at both EOT and 12 weeks after EOT. Fourteen (18.7%) out of 75 patients (all study populations) had intra-PBMC HCV RNA, but only nine of them (64.3%) developed HCV RNA serum relapse (seroconversion) 12 weeks after EOT (P < 0.001). Encephalopathy was significantly higher in group C at EOT and 12 weeks after EOT (P < 0.05). Development of HCC was observed in decompensated patients of group C (2 out of 5 = 40.0%) 12 weeks post-EOT (P = 0.03). In conclusion, detection of HCV RNA within PBMCs at the EOT provides an indication of potential relapse after 12 weeks. Moreover, development of encephalopathy and HCC after HCV eradication by SOF plus LDV therapy is perhaps a future warning for post-treatment hepatic decompensation in cirrhotic patients.

Authentic Patient-Derived Hepatitis C Virus Infects and Productively Replicates in Primary CD4+ and CD8+ T Lymphocytes In Vitro

Accumulated evidence indicates that immune cells can support the replication of hepatitis C virus (HCV) in infected patients and in culture. However, there is a scarcity of data on the degree to which individual immune cell types support HCV propagation and on characteristics of virus assembly. We investigated the ability of authentic, patient-derived HCV to infect in vitro two closely related but functionally distinct immune cell types, CD4⁺ and CD8⁺ T lymphocytes, and assessed the properties of the virus produced by these cells. The HCV replication system in intermittently mitogen-stimulated T cells was adapted to infect primary human CD4⁺ or CD8⁺ T lymphocytes. HCV replicated in both cell types although at significantly higher levels in CD4⁺ than in CD8⁺ T cells. Thus, the HCV RNA replicative (negative) strand was detected in CD4⁺ and CD8⁺ cells at estimated mean levels ± standard errors of the means of 6.7 × 10² ± 3.8 × 10² and 1.2 × 10² ± 0.8 × 10² copies/μg RNA, respectively (P < 0.0001). Intracellular HCV NS5a and/or core proteins were identified in 0.9% of CD4⁺ and in 1.2% of CD8⁺ T cells. Double staining for NS5a and T cell type-specific markers confirmed that transcriptionally competent virus replicated in both cell types. Furthermore, an HCV-specific protease inhibitor, telaprevir, inhibited infection in both CD4⁺ and CD8⁺ cells. The emergence of unique HCV variants and the release of HCV RNA-reactive particles with biophysical properties different from those of virions in plasma inocula suggested that distinct viral particles were assembled, and therefore, they may contribute to the pool of circulating virus in infected patients.IMPORTANCE Although the liver is the main site of HCV replication, infection of the immune system is an intrinsic characteristic of this virus independent of whether infection is symptomatic or clinically silent. Many fundamental aspects of HCV lymphotropism remain uncertain, including the degree to which different immune cells support infection and contribute to virus diversity. We show that authentic, patient-derived HCV productively replicates in vitro in two closely related but functionally distinct types of T lymphocytes, CD4⁺ and CD8⁺ cells. The display of viral proteins and unique variants, the production of virions with biophysical properties distinct from those in plasma serving as inocula, and inhibition of replication by an antiviral agent led us to ascertain that both T cell subtypes supported virus propagation. Infection of CD4⁺ and CD8⁺ T cells, which are central to adaptive antiviral immune responses, can directly affect HCV clearance, favor virus persistence, and decisively influence the development and progression of hepatitis C.

Evolution of the Humoral Response during HCV Infection: Theories on the Origin of Broadly Neutralizing Antibodies and Implications for Vaccine Design

Similar to human immunodeficiency virus (HIV)-1, vaccine-induced elicitation of broadly neutralizing (bNt) antibodies (Abs) is gaining traction as a key goal toward the eradication of the hepatitis C virus (HCV) pandemic. Previously, the significance of the Ab response against HCV was underappreciated given the prevailing evidence advancing the role of the cellular immune response in clearance and overall control of the infection. However, recent findings have driven growing interest in the humoral arm of the immune response and in particular the role of bNt responses due to their ability to confer protective immunity upon passive transfer in animal models. Nevertheless, the origin and development of bNt Abs is poorly understood and their occurrence is rare as well as delayed with emergence only observed in the chronic phase of infection. In this review, we characterize the interplay between the host immune response and HCV as it progresses from the acute to chronic phase of infection. In addition, we place these events in the context of current hypotheses on the origin of bNt Abs against the HIV-1, whose humoral immune response is better characterized. Based on the increasing significance of the humoral immune response against HCV, characterization of these events may be critical in understanding the development of the bNt responses and, thus, provide strategies toward effective vaccine design.

Peripheral Blood Mononuclear Cell Gene Expression Remains Broadly Altered Years after Successful Interferon-Based Hepatitis C Virus Treatment

Background. Inflammatory gene expression in peripheral blood mononuclear cells (PBMCs) is altered in chronic Hepatitis C Virus (HCV) infection. Duration of changes after pegylated interferon- (peg-IFN-) based HCV treatment is unclear. Methods. PBMC mRNA expression of 184 inflammatory response genes was analyzed (nCounter GX Human Inflammation Kit, Nanostring) from peg-IFN treatment nonresponders (NR, n = 18), sustained virologic responders (SVR, n = 22), and spontaneous clearers (SC, n = 15). Logistic regression was used for comparison. Results. Median time from last treatment was 2 and 2.7 years in SVR and NR, respectively (p = NS). Mean mRNA counts were significantly different for 42 and 29 genes comparing SVR to SC patients and NR to SC, respectively, and no genes comparing SVR to NR. Differential expression of 24 genes was significantly different in both SVR and NR groups compared to SC. Among these 24 acute and chronic inflammatory cascade genes, significant upregulation was noted for proinflammatory transcription regulators Fos, CEBPB, and MyD88 in SVR and NR compared to SC. HDAC4 was significantly downregulated in SVR and NR compared to the SC group. Conclusions. PBMC inflammatory gene expression patterns in SVR resemble NR more than SC patients. A generalized inflammatory response persists in PBMCs long after successful peg-IFN treatment for HCV infection.

Persistence of Hepatitis C Virus Traces after Spontaneous Resolution of Hepatitis C

Hepatitis C virus (HCV) frequently causes chronic hepatitis, while spontaneous recovery from infection is infrequent. Persistence of HCV after self-limited (spontaneous) resolution of hepatitis C was rarely investigated. The current study aimed to assess incidence and robustness of HCV persistence after self-resolved hepatitis C in individuals with normal liver enzymes and undetectable virus by conventional tests. Applying high sensitivity HCV RNA detection approaches, we analyzed plasma and peripheral blood mononuclear cells (PBMC) from individuals with previous hepatitis C infection. Parallel plasma and PBMC from 24 such non-viraemic individuals followed for 0.3–14.4 (mean 6.4) years were examined. Additional samples from 9 of them were obtained 4.5–7.2 (mean 5.9) years later. RNA was extracted from 250 μl plasma and, if HCV negative, from ~5 ml after ultracentrifugation, and from ex vivo stimulated PBMC. PBMC with evidence of HCV replication from 4 individuals were treated with HCV protease inhibitor, telaprevir. HCV RNA was detected in 14/24 (58.3%) plasma and 11/23 (47.8%) PBMC obtained during the first collection. HCV RNA replicative strand was evident in 7/11 (63.6%) PBMC. Overall, 17/24 (70.8%) individuals carried HCV RNA at mean follow-up of 5.9 years. Samples collected 4.5–7.2 years later revealed HCV in 4/9 (44.4%) plasma and 5/9 (55.5%) PBMC, while 4 (80%) of these 5 PBMC demonstrated virus replicative strand. Overall, 6/9 (66.7%) individuals remained viraemic for up to 20.7 (mean 12.7) years. Telaprevir entirely eliminated HCV replication in the PBMC examined. In conclusion, our results indicate that HCV can persist long after spontaneous resolution of hepatitis C at levels undetectable by current testing. An apparently effective host immune response curtailing hepatitis appears insufficient to completely eliminate the virus. The long-term morbidity of asymptomatic HCV carriage should be examined even in individuals who achieve undetectable HCV by standard testing and their need for treatment should be assessed.

A New Twist to a Chronic HCV Infection: Occult Hepatitis C

Background. The prevalence of occult hepatitis C infection (OCI) in the population of HCV-RNA negative but anti-HCV positive individuals is presently unknown. OCI may be responsible for clinically overt recurrent disease following an apparent sustained viral response (SVR) weeks to years later. Purpose. To review the available current literature regarding OCI, prevalence, pathogenic mechanisms, clinical characteristics, and future directions. Data Sources. Searching MEDLINE, article references, and national and international meeting abstracts for the diagnosis of OCI (1990-2014). Data Synthesis. The long-term followup of individuals with an OCI suggests that the infection can be transient with the loss of detectable HCV-RNA in PPBMCs after 12-18 months or alternatively exist intermittently and potentially long term. The ultimate outcome of HCV infection is decided by interplay between host immune responses, antiviral therapies, and the various well-identified viral evasion mechanisms as well as the presence of HCV infection within extrahepatic tissues. Conclusion. The currently widely held assumption of a HCV-cure in individuals having had "SVR" after 8-12 weeks of a course of DAA therapy as recently defined may not be entirely valid. Careful longitudinal followup utilizing highly sensitive assays and unique approaches to viral isolation are needed.

Differential expression of interferon alpha inducible genes in peripheral blood mononuclear cells from patients chronically infected with hepatitis C virus and healthy donors

The impact of exposure to interferon-alpha (IFN-α) on gene expression in peripheral blood mononuclear cells (PBMC) from hepatitis C virus (HCV)-infected and healthy individuals was investigated to recognize whether their PBMC differ in expression of IFN-inducible genes (ISGs) following treatment with IFN-α2b. PBMC obtained from healthy and treatment-naïve HCV-infected patients were cultured with IFN-α2b for 30min, 2h, 4h and 72h, and gene expression was analyzed using mRNA microarray technology. IFN-α caused differential up-regulation of many known ISGs in PBMC from both HCV-infected and healthy subjects. In comparison to untreated controls, the highest augmentation in PBMC ISG expression occurred after 4-hour exposure to IFN-α2b in both groups. The analysis identified 84 transcripts, representing 64 known and 2 unknown genes, that were up-regulated by at least 5-fold in PBMC from infected and uninfected individuals. However, the expression of IFN-α inducible genes was impaired in the PBMC from HCV-infected individuals compared to healthy controls. This was due to an increased baseline expression of the transcripts in PBMC of HCV-infected patients. These findings expand our understanding of IFN-responses in HCV-infected individuals and suggest that functions of PBMC, which include immune effector cells, are altered in patients chronically infected with HCV.

IFNL4 and IFNL3 associated polymorphisms strongly influence the spontaneous IFN-alpha receptor-1 expression in HCV-infected patients

Single-nucleotide polymorphism in IFNL3 gene (rs12979860) predicts spontaneous and therapy-induced HCV clearance. In a previous study from our group PBMC from patients with favourable rs12979860 genotype showed higher levels of IFNAR-1 mRNA. Recently, a dinucleotide polymorphism, ss469415590 (TT or ΔG), has been discovered in the region upstream IFNL3 gene, which is in high linkage disequilibrium with rs12979860. ss469415590[ΔG] is a frameshift variant that creates a novel gene, designed IFNL4, encoding the interferon-lambda 4 protein (IFNL4). The aim of the present study was to extend the analysis of IFNAR-1 mRNA levels to the ss469415590 variants. Our results highlight that the difference of IFNAR-1 mRNA levels between favourable and unfavourable genotype combinations, at both rs12979860 and ss469415590 loci, is stronger than that observed for single polymorphisms at each locus. These findings suggest may represent the biological basis for the observed association between IFNL3 CC and IFNL4 TT/TT genotypes and favourable outcome of either natural HCV infection (clearance vs chronic evolution) or IFN-based therapy.

Iron homeostasis and its regulators over the course of chronic hepatitis C

ABSTRACT: 

Chronic infection with HCV has been diagnosed in approximately 170 million people worldwide. It is an important cause of chronic, progressive liver fibrosis. Late consequences of chronic HCV infection, including liver cirrhosis and hepatocellular carcinoma, have become the major indications for liver transplantation in developed countries. Particular attention is being paid to iron accumulation in chronic hepatitis C and its relation to the current antiviral therapy's efficacy and safety, risk of exacerbation of oxidative stress, development of metabolic disorders and hepatocarcinogenesis. HCV infection disrupts the synthesis of hepcidin, which regulates extracellular iron content. This article discusses the impact of iron on HCV multiplication and the involvement of impaired iron homeostasis in chronic hepatitis C in terms of the pathogenesis of insulin resistance, fatty liver and hepatocarcinogenesis.

Review: Occult hepatitis C virus infection: still remains a controversy

Occult hepatitis C virus (HCV) infection is characterized by the presence of HCV RNA in the liver cells or peripheral blood mononuclear cells of the patients whose serum samples test negative for HCV RNA, with or without presence of HCV antibodies. The present study reviews the existing literature on the persistence of occult hepatitis C virus infection, with description of the clinical characteristics and methods for identification of occult hepatitis C. Occult hepatitis C virus infection was detected in patients with abnormal results of liver function tests of unknown origin, with HCV antibodies and HCV RNA negativity in serum, and also in patients with spontaneous or treatment-induced recovery from hepatitis C. The viral replication in the liver cells and/or peripheral blood mononuclear cells was present in all clinical presentations of occult hepatitis C. The peripheral blood mononuclear cells represent an extra-hepatic site of HCV replication. The reason why HCV RNA was not detectable in the serum of patients with occult hepatitis C, could be the low number of circulating viral particles not detectable by the diagnostic tests with low sensitivity. It is uncertain whether occult hepatitis C is a different clinical entity or just a form of chronic hepatitis C virus infection. Data accumulated over the last decade demonstrated that an effective approach to the diagnosis of HCV infection would be the implementation of more sensitive HCV RNA diagnostic assays, and also, examination of the presence of viral particles in the cells of the immune system.