It is believed that the hepatitis C virus (HCV)-specific CD8⁺cytotoxic T lymphocytes (CTLs) play a role in the development of liver cell injury and in the clearance of the virus. To develop a direct binding assay for HCV-specific CTLs, we generated two peptide-MHC tetramers by using the recombinant HLA A2.1 molecule and A2-restricted T cell epitopes of the HCV NS3 protein. With these reagents we are able to detect specific CD8⁺cells in the blood of 15 of 20 HLA-A2⁺, HCV-infected patients, at a frequency ranging from 0.01% to 1.2% of peripheral CD8⁺T cells. Phenotypic analysis of these specific cells indicated that there is a significant variation in the expression of the CD45 isoforms and CD27 in different patients. A 6-hour incubation of one patient’s blood with NS3 peptides resulted in the activation of the epitope-specific CD8⁺cells, as indicated by their expression of CD69 and IFN-γ. We also detected NS3-specific CD8⁺T cells in the intrahepatic lymphocyte population isolated from liver biopsies of two HCV-infected patients. The frequency of these specific CD8⁺cells in the liver was 1–2%, at least 30-fold higher than in the peripheral blood. All of the intrahepatic NS3-specific CD8⁺T cells were CD69⁺, suggesting that they were activated CTLs. Direct quantitation and characterization of HCV-specific CTLs should extend our understanding of the immunopathogenesis and the mechanism of clearance or persistence of HCV.

Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of about 9,600 nucleotides. It is a major cause of liver disease, infecting almost 200 million people all over the world. Similarly to most RNA viruses, HCV displays very high levels of genetic diversity which have been used to differentiate six major genotypes and about 80 subtypes. Although the different genotypes and subtypes share basic biological and pathogenic features they differ in clinical outcomes, response to treatment and epidemiology. The first HCV recombinant strain, in which different genome segments derived from parentals of different genotypes, was described in St. Petersburg (Russia) in 2002. Since then, there have been only a few more than a dozen reports including descriptions of HCV recombinants at all levels: between genotypes, between subtypes of the same genotype and even between strains of the same subtype. Here, we review the literature considering the reasons underlying the difficulties for unequivocally establishing recombination in this virus along with the analytical methods necessary to do it. Finally, we analyze the potential consequences, especially in clinical practice, of HCV recombination in light of the coming new therapeutic approaches against this virus.

Metagenomic high-throughput sequencing (mHTS) is a hypothesis-free, universal pathogen detection technique for determination of the DNA/RNA sequences in a variety of sample types and infectious syndromes. mHTS is still in its early stages of translating into clinical application. To support the development, implementation and standardization of mHTS procedures for virus diagnostics, the European Society for Clinical Virology (ESCV) Network on Next-Generation Sequencing (ENNGS) has been established. The aim of ENNGS is to bring together professionals involved in mHTS for viral diagnostics to share methodologies and experiences, and to develop application recommendations. This manuscript aims to provide practical recommendations for the wet lab procedures necessary for implementation of mHTS for virus diagnostics and to give recommendations for development and validation of laboratory methods, including mHTS quality assurance, control and quality assessment protocols.

An increase in the number of hepatitis C virus (HCV)-infected transplant recipients at need for repeated liver transplantation is anticipated. To date, there is a certain reluctance to accept these patients because of an increased organ shortage, early reports suggesting a poor outcome, and uncertainty regarding the natural history of recurrent hepatitis C in the second graft. The aim of this study is to determine the outcome of patients undergoing retransplantation for HCV-related graft cirrhosis. Of 49 transplant recipients with HCV-related allograft cirrhosis, 31 patients developed decompensation with criteria for retransplantation. Thirteen patients were denied this option. Of the 18 patients accepted, 6 patients died while on the waiting list (5 patients died of graft cirrhosis at a median of 3.2 months of listing), and 12 patients have undergone retransplantation (median, 10 months since HCV cirrhosis). After retransplantation, 8 patients (67%) died at a median of 8 months, and 4 patients (33%) remain alive after 1.9 years of follow-up. Causes and times of death from retransplantation were: surgical complications, n = 3 (perioperative period) HCV cirrhosis of the second graft, n = 2 (at 9 and 54 months) fibrosing cholestatic hepatitis, n = 1 (at 2 years) lymphoproliferative disorder, n = 1 (at 7 months) and endocarditis, n = 1 (at 3.5 years, with underlying cirrhosis). Of the 4 patients alive, fibrosis stages in the last biopsy specimens are stage 1 (n = 1), stage 3 (n = 1), and stage 4 or cirrhosis (n = 1; one patient has not undergone biopsy), despite antiviral therapy. The outcome of retransplantation for HCV cirrhosis of the first graft is very poor because of multiple complications. The severity of recurrent HCV disease in the second graft seems to be related to that observed in the first graft.