Clinical Laboratory Testing in the Era of Directly Acting Antiviral Therapies for Hepatitis C

Comprehensive evaluation of the mechanism of human adipose mesenchymal stem cells ameliorating liver fibrosis by transcriptomics and metabolomics analysis

Liver fibrosis is a chronic liver disease with progressive wound healing reaction caused by liver injury. Currently, there is no FDA approved drugs for liver fibrosis. Human adipose mesenchymal stem cells (hADSCs) have shown remarkable therapeutic effects in liver diseases. However, few studies have evaluated the therapeutic role of hADSCs in liver fibrosis, and the detailed mechanism of action is unknown. Here, we investigated the in vitro and in vivo anti-fibrosis efficacy of hADSCs and identified important metabolic changes and detailed mechanisms through transcriptomic and metabolomic analyses. We found that hADSCs could inhibit the proliferation of activated hepatic stellate cells (HSCs), promote their apoptosis, and effectively inhibit the expression of pro-fibrotic protein. It can significantly reduce collagen deposition and liver injury, improve liver function and alleviate liver inflammation in cirrhotic mouse models. In addition, transcriptome analysis revealed that the key mechanism of hADSCs against liver fibrosis is the regulation of AGE-RAGE signaling pathway. Metabolic analysis showed that hADSCs influenced changes of metabolites in lipid metabolism. Therefore, our study shows that hADSCs could reduce the activation of hepatic stellate cells and inhibit the progression of liver fibrosis, which has important potential in the treatment of liver fibrosis as well as other refractory chronic liver diseases.

Immunity of two novel hepatitis C virus polyepitope vaccines

Hepatitis C virus (HCV) infection remains a serious public health burden around the world. So far there is no effective vaccine against this virus. Neutralizing antibody (NAb) responses to the epitopes within HCV E1 and E2 proteins are related to the resolution of hepatitis C infection. E. coli heat-labile enterotoxin B subunit (LTB) has been described as potent immunity adjuvants. In this study, we constructed recombinant pET vectors: pET-R9-Bp (B cell polyepitopes) expressing 7 epitopes from HCV E1 and E2 proteins including R9 (E2_384-411aa)-Bp (E1_313-327aa-E2_396-424aa-E2_436-447aa-E2_523-540aa-E2_610-627aa-E2_631-648aa) and pET-LTB-R9-Bp expressing LTB adjuvant in combination with R9-Bp. Recombinant proteins R9-Bp and LTB-R9-Bp were expressed successfully in E. coli and purified by the Ni-NTA column. Both R9-Bp and LTB-R9-Bp in BALB/c mice induced robust humoral immune response in the context of intraperitoneal or intramuscular immunization but not oral immunization. Intraperitoneal administration of LTB-R9-Bp induced a higher antibody titer (peak titer: 1:341000) than that of R9-Bp (peak titer: 1:85000) after the second boost (P = 0.0036 or 0.0002). However, comparable antibody peak titers were elicited for both R9-Bp and LTB-R9-Bp in intramuscular immunization albeit with significant difference (P = 0.0032) a week after the second boost. In addition, both R9-Bp and LTB-R9-Bp induced the secretion of cytokines including IFN-γ and IL-4 at similar levels. anti-sera induced by both R9-Bp and LTB-R9-Bp recognized native HCV E1 and E2 proteins. Moreover, these HCV-specific antisera inhibited significantly the entry of HCV (P < 0.0001). Taken together, these findings showed that E. coli-based both R9-Bp and LTB-R9-Bp could become promising HCV vaccines.

Current position of viral load versus hepatitis C core antigen testing

Quantification of hepatitis C virus (HCV) RNA (viral load) is the most widely used marker to diagnose and confirm active HCV infection. The HCV core antigen forms part of the internal structure of the virus and, like HCV RNA, its detection also indicates viral replication and presents certain advantages over viral load testing such as its lower cost, the greater stability of the target, the possibility of working with the same primary tube as that used for HCV serology, and the rapidity of obtaining results, since there is no need to work in batches, unlike the situation with most viral load platforms. Although the core antigen has lower analytical sensitivity than HCV RNA for the detection of low viremia levels, several studies and guidelines have already shown their utility in the identification of patients with active HCV infection. This article summarises current platforms for viral load determination, including point-of-care systems, and also reviews the indications attributed to this marker by the main HCV treatment guidelines. The article also reviews the characteristics of HCV core antigen, the available platforms for its determination, its correlation with viral load determination, and the indications for this marker in the distinct guidelines.

Correlation of serostatus and viraemia levels among Indian dengue patients at the time of first diagnosis

BACKGROUND

Dengue is a public health problem worldwide. Therapeutic monoclonal antibodies (MAbs) against dengue virus (DENV) are likely to be available soon. In view of the feasibility issues pertaining to pretreatment viraemia quantitation for therapy decisions, we conducted this study for investigation of a correlation between patient serostatus (NS1/immunoglobulin M [IgM]/IgG) and viraemia levels among Indian dengue patients at the time of first diagnosis.

METHODS

The study included 297 serum samples from dengue patients in Pune, India. The samples were tested for NS1, IgM and IgG (capture enzyme-linked immunosorbent assay [ELISA] for identifying secondary dengue) using Panbio ELISAs. Quantitation of viraemia was conducted using an NS1 ELISA-based 50% tissue culture infectious dose (TCID50) test in Vero cells.

RESULTS

Viraemia was detectable only among NS1-positive patients (n = 229, range 0.5-8.3 logTCID50/ml) with a mean titre of 1.9 logTCID50/ml. Among the NS1-positive patients, DENV titres were higher in IgM-negative than IgM-positive patients (p < 0.0001) and in primary (IgG < 18 Panbio units) versus secondary (IgG > 22 Panbio units) dengue patients (p = 0.002). Virus titres were higher during the first 3 days of illness and decreased later (p = 0.005).

CONCLUSIONS

The study provides a range of infectious DENV titres in relation to serologic status among dengue patients in India. The data suggest the possibility of using serological markers (NS1/IgM) as a basis for treatment decisions.

HCV Genotype Distribution of Patients with Chronic Hepatitis C in Istanbul

Objectives:

Hepatitis C virus (HCV), which has no protective vaccine, is a common cause of chronic hepatitis, which is a severe public health threat. There are differences in nucleotide and amino acid sequences in different regions of the HCV genome. As a result of these differences, HCV has been shown to have at least seven major genotypes and many subtypes. In Turkey, the prevalence of genotype 1 is between 51.7% and 97.1%, the highest rate among all genotypes, while subtype 1b is the genotype with the highest rate. It is important to detect mixed genotype infection reliably as it causes treatment failure. This study aims to reveal the distribution of the HCV genotypes in our hospital in Istanbul over the years and to contribute to the epidemiological data of Turkey.

Methods:

For this purpose, 385 patient samples sent to Sisli Hamidiye Etfal Training and Research Hospital, Clinical Microbiology Laboratory for HCV genotype determination between January 2016 and June 2019 were evaluated retrospectively. Anti-HCV was screened by enzyme immunoassay and confirmation was performed by Line immunoassay. HCV genotyping assays targeting highly conserved 5’UTR and most variable region NS5B regions were used.

Results:

The most common genotype was genotype 1 (81.3%) with 313 cases and subtypes 1a and 1b were detected at the rates of 10.9% and 67.8%, respectively. In addition, genotype 3, 2, 4, 5 were detected at the rates of 8.8%, 3.4%, 2.9%, 0.8%, respectively and mixed genotype was found in 2.9% of cases. Although genotype 5 is seen in South Africa, it is found in the Middle East region, albeit at a low rate. In our study, it was observed that genotype 5 was detected in different years from patients of Syrian origin.

Conclusion:

In this study, genotype 1 was the most common genotype with a rate of 81.3% and subtype 1b was 67.8%, in accordance with the literature. However, genotypes 3, 2, 4 and 5 were also present at low rates. It is important to monitor these rare genotypes since some of them are dominant in surrounding countries. In addition, 2.9% of HCV mixed genotype was detected and this should be considered concerning management of HCV infection.

Sofosbuvir and Ribavirin Combination Therapy Response in Various Hepatitis C Virus Genotypes in Peshawar, Khyber Pakhtunkhwa

Background: Approximately 3% of the population worldwide is infected with Hepatitis C Virus (HCV). Different regimens have been used to treat HCV, each of which has its side effects and efficacy. Sofosbuvir, a direct-acting antiviral drug, has replaced all previous regimens with the highest response rate. However, its response is not fully covered in Pakistan, especially Khyber Pakhtunkhwa. Objectives: The study aimed to examine the response to Sofosbuvir and Ribavirin combination therapy in chronic HCV patients infected with various HCV genotypes. Methods: This study was conducted in Tertiary Care Hospitals, Peshawar, Pakistan. The patients were enrolled from January 2016 to March 2017. A total of 80 patients (57 naïve and 23 non-responder) were enrolled in this study. The age range was 16 - 70 years, and the mean age was 36 ± 2 years. Genotyping, biochemical profile, PCR tests, and liver ultrasounds were done for all of the enrolled subjects at the start and end of therapy. All patients were given direct-acting antiviral drugs for six months and then, the end of treatment response was noted. Results: A total of 80 subjects with HCV infection took part in the study, including 57 (71.25%) treatment-naïve and 23 (28.75%) treatment non-responding patients. The end of therapy response was reported after 24 weeks of treatment. Among the 80 patients, 72 (90%) patients achieved the end of therapy response. The highest end of therapy response (100%) was noted in genotype 1 and mixed genotypes and patients with normal liver ultrasound. The lowest end of therapy response (70%) was found in un-type genotype and patients with an abnormal texture of liver ultrasound. The end of therapy response rate was higher in females than in males. Conclusions: In the current study, the minimal response was found in un-type genotypes and genotypes that did not respond to INF, as compared to treatment-naïve subjects. Further research is needed to understand the relevant host and viral factors, with particular attention to relapsed patients and non-responders that are difficult to treat in the Pakistani population.

Economic impact of health resource optimisation in the approach to patients with hepatitis C

TThe incorporation of direct-acting antiviral agents to the treatment of chronic hepatitis C infection has simplified diagnosis and follow-up, allowing optimisation of health resources (consultations and tests) dedicated to the management of the disease. The aim of this study was to estimate the economic impact of this simplification. Health resource optimisation was estimated through the Delphi method, based on a panel of 36 experts, consisting of Spanish clinicians, and on clinical practice guidelines. The unit costs (€ in 2017) of the health resources included were obtained from Spanish sources. Simplification of the process, as well as liaison between the medical specialist, nurses and the pharmacy service, would generate savings of €591.17 per patient. Likewise, the mean length of consultations would be shorter with regimens of only 1 tablet daily compared with regimens of more than 1 tablet daily. Supplement information: This article is part of a supplement entitled "The value of simplicity in hepatitis C treatment", which is sponsored by Gilead. © 2019 Elsevier España, S.L.U. All rights reserved.

Sofosbuvir/velpatasvir/voxilaprevir: a highly effective option for retreatment of hepatitis C in difficult-to-treat patients

Treatment for hepatitis C has escalated rapidly since the advent of direct-acting antivirals. Although there are highly efficacious, pangenotypic regimens available as standard of care, 5-10% of patients do not achieve virological cure. The recently approved fixed-dose combination of sofosbuvir, velpatasvir and voxilaprevir provides an option for retreatment in patients who have failed prior regimens and have characteristics which make them difficult to treat. This review provides a summary of the evidence for use of Vosevi^®, a fixed-dose combination pill for treatment of hepatitis C in treatment-experienced patients.

VirGenA: a reference-based assembler for variable viral genomes

Characterization of the within-host genetic diversity of viral pathogens is required for selection of effective treatment of some important viral infections, e.g. HIV, HBV and HCV. Despite the technical ability of detection, there are conflicting data regarding the clinical significance of low-frequency variants, partially because of the difficulty of their distinguishing from experimental artifacts. The issue of cross-contamination is relevant for all highly sensitive techniques, including deep sequencing: even trace contamination leads to a significant increase of false positives in identified SNVs. Determination of infections by multiple genotypes of some viruses, the incidence of which can be considerable, especially in risk groups, is also clinically significant in some cases. We developed a new viral reference-guided assembler, VirGenA, that can separate mixtures of strains of different intraspecies genetic groups (genotypes, subtypes, clades, etc.) and assemble a separate consensus sequence for each group in a mixture. It produced long assemblies for mixture components of extremely low frequencies (<1%) allowing detection of cross-contamination of samples by divergent genotypes. We tested VirGenA on both clinical and simulated data. On both types of data, VirGenA shows better or similar results than the existing de novo assemblers. Cross-platform implementation (including source code) is freely available at https://github.com/gFedonin/VirGenA/releases.

Sofosbuvir/velpatasvir: a pangenotypic drug to simplify HCV therapy

Treatment for chronic hepatitis C virus (HCV) has evolved rapidly from an interferon based regimen of modest efficacy with significant adverse events to a well-tolerated, highly effective all-oral directly acting antiviral (DAA) therapy. Although significant improvement in sustained virologic responses (SVR) has been reported with new DAAs for genotypes 1 and 4, effective treatments for genotype 3 have been lacking, and a single pill that can yield high SVR rates against HCV genotypes 1-6 has not been available until now. Sofosbuvir (a pangenotypic NS5B inhibitor) and velpatasvir (a pangenotypic NS5A inhibitor) were recently approved in a fixed-dose combination pill. The availability of this pangenotypic pill holds promise for providing highly effective treatment with minimal laboratory testing for chronic HCV worldwide.