The Procleix HEV ID-NAT screening system has provided evidence of HEV RNA presence in Catalan blood donors. Further data are needed to assess the impact of HEV infection in at-risk patients to design the best strategy to increase blood safety.
There are seven confirmed hepatitis C virus (HCV) genotypes, with whole-genome nucleotide sequences differing by Ͼ30%, and each can be further subdivided into related subtypes (67 confirmed), with nucleotide sequence divergence of between 15% and 30% (1).Genotype identification has long been used in clinical practice, because major genotypes have different response rates and require different doses and durations of pegylated interferon and ribavirin (PR) treatment. In contrast, until recently, subtype identification was mainly used in epidemiological studies. However, both in vitro studies and clinical trials with different classes of direct-acting antiviral (DAA) agents (NS3 protease, NS5A-, and nucleos[t]ide and nonnucleos[t]ide NS5B-polymerase inhibitors), given with PR or in interferon-free combinations, have shown lower response rates for HCV genotype 1a than for HCV genotype 1b (2-8). Moreover, at least for HCV genotype 1, both the frequency and the pattern of resistance to different DAA classes are subtype specific (9). A striking example is the NS3-Q80K polymorphism, naturally found in Ͼ30% of naive subtype 1a patients but in Ͻ1% of subtype 1b patients (10), which conveys 30%-to-40%-lower sustained-virologic-response (SVR) rates to the macrocyclic protease inhibitor simeprevir (2). Similarly, all subtype 1g sequences identified naturally carry a mutation conferring resistance to linear NS3 protease inhibitors (11).Subtype-specific differences in the genetic barrier to resistance appear to correlate to the RNA-dependent RNA polymerase mu-
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An increasing number of new hepatitis C virus NS3-protease inhibitors are being evaluated for the treatment of chronic hepatitis C. Treatment-induced selection of mutants conferring resistance to protease inhibitors has been shown both in vivo and in vitro. A specific mutation, A156T has been shown to confer high-level resistance to several such agents (BILN2061, VX-950, SCH446211 (SCH6) and SCH503034). Here we report the presence of the A156T mutation in close to 1% of NS3 sequences within the liver quasispecies of a chronic hepatitis C patient never treated with anti-NS3-protease inhibitors.
HBsAg levels varied across genotypes in HBeAg-negative patients. HBsAg levels <3 logIU/mL were only useful for identifying genotype D inactive carriers. A single HBcrAg measurement ≤3 logU/mL plus HBV DNA ≤2000 IU/mL was highly accurate for identifying inactive carriers, regardless of their HBV genotype.
These findings confirm that approximately half of RIBA-indeterminate donors have resolved a previous HCV infection and suggest that ELISpot might be a useful tool to clarify the status of such donors and help in their counseling and management.
Injection of dendritic cells (DCs) presenting viral proteins constitutes a promising approach to stimulate T cell immunity against hepatitis C virus (HCV). Here we describe a strategy to enhance antigen loading and immunostimulatory functions of DCs useful in the preparation of therapeutic vaccines. Incubation of murine DCs with CFm40L, an adapter molecule containing the coxsackie-adenovirus receptor fused to the ecto-domain of murine CD40L-induced DC maturation, produced high amounts of interleukin-12 and up-regulation of molecules associated with T helper 1 responses. Accordingly, targeting of an adenovirus encoding HCV NS3 protein (AdNS3) to DCs with CFm40L strongly enhanced NS3 presentation in vitro, activating interferon-c-producing T cells. Moreover, immunization of mice with these DCs promoted strong CD4 and CD8 T cell responses against HCV NS3. CFh40L, a similar adapter molecule containing human CD40L, enhanced transduction and maturation of human monocyte-derived DCs. Comparison of DCs transduced with AdNS3 and CFh40L from patients with chronic HCV infection and healthy donors revealed similar maturation levels. More importantly, DCs from the patients induced NS3-specific responses when transduced with AdNS3 and CFh40L but not with AdNS3 alone. Conclusion: DCs transduced with AdNS3 and the adapter molecule CFm/h40L exhibit enhanced immunostimulatory functions, induce robust anti-HCV NS3 immunity in animals, and can induce antiviral immune responses in subjects with chronic HCV infection. This strategy may serve as therapeutic vaccination for patients with chronic hepatitis C. (HEPATOLOGY 2011;54:28-37) T he antiviral T cell immunity found in patients with chronic hepatitis C virus (HCV) infection is characterized by its low magnitude and the narrow repertoire of epitopes recognized by T cells. By contrast, individuals who clear the virus have strong and multispecific T cell responses against viral antigens. 1 These results suggest that T cell immunity may be responsible for viral clearance and support the notion that induction of these responses may be advantageous for the treatment of chronic hepatitis C.
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