IFN-free therapy is associated with restoration of type I IFN response in HIV-1 patients with acute HCV infection who achieve SVR

Interferon (IFN)-free direct-acting antiviral agents (DAAs) have revolutionized chronic hepatitis C virus (HCV) treatment; early studies suggest excellent efficacy in acute HCV. However, changes in innate immune responses during DAA therapy for acute HCV are unknown. We studied interferon-stimulated gene (ISG) expression and related cytokines/chemokines in HIV-infected patients with acute HCV receiving sofosbuvir plus ribavirin (SOF+RBV) as part of the A5327 clinical trial. ISG expression was determined from PBMCs, and circulating cytokines/chemokines were quantified from serum from study participants. The overall sustained virologic response (SVR) was 57%; all treatment failures were due to virologic relapse. Apart from NOS2a, baseline ISG/chemokine/cytokine levels were similar irrespective of treatment outcome. Downregulation of ISGs was observed at treatment week four and end of treatment (EOT), implicating HCV in establishing elevated ISGs early during HCV infection. Levels of many of these ISGs increased at post-treatment week 12 (PTW12) in relapsers only, coinciding with recurrent HCV RNA. Eleven ISGs were differentially expressed in responders vs relapsers. On-treatment viral suppression was also associated with a reduction in IP-10, CXCL11 and MIP-1β levels. In contrast, circulating IFN-α levels were significantly higher at EOT and PTW12 in responders vs relapsers. Upregulation of peripheral ISG expression is established early in the course of HCV infection during acute HCV infection, but did not predict subsequent treatment outcome with SOF+RBV. ISGs were downregulated during therapy and increased post-therapy in relapsers. IFN-α levels were higher in responders at EOT/PTW12, suggesting that impaired type I IFN production/secretion may contribute to relapse.

Sofosbuvir and ledipasvir improve patient-reported outcomes in patients co-infected with hepatitis C and human immunodeficiency virus

A fixed-dose combination of ledipasvir and sofosbuvir (LDV/SOF) has been approved for treatment of HCV patients. We assessed the effect of LDV/SOF on patient-reported outcomes (PROs) in HIV-HCV-co-infected patients. Patient-reported outcomes data from HIV-HCV-co-infected patients who were treated with LDV/SOF for 12 weeks were collected as a part of a clinical trial (ION-4). Historical controls were HIV-HCV-co-infected patients treated with SOF and ribavirin (RBV) in PHOTON-1. We included 335 HIV-HCV-co-infected patients (SVR-12 in HCV genotype 1 was 96%) who received LDV/SOF, while 223 patients (SVR-12 in HCV genotype 1 was 76.3%) received SOF/RBV. During treatment, patients receiving LDV/SOF showed improvement in all of their PRO scores (+6.0% in activity/energy of CLDQ-HCV, +5.0% in fatigue score of FACIT-F, +6.8% in physical component of SF-36; all P < 0.0001) while those receiving SOF+RBV showed moderate decline in some of their PRO scores (-4.8% in physical functioning of SF-36, -4.4% in fatigue score of FACIT-F, both P < 0.001). Patients who achieved sustained virologic response with LDV/SOF also showed improvement of PROs (average +5.1%) while those treated with SOF/RBV showed less or no improvement (average +1.4%). In a multivariate analysis, in addition to depression and fatigue, receiving SOF+RBV (vs LDV/SOF) was independently associated with more PRO impairment during treatment (beta -6.1 to -12.1%, P < 0.001). Hence, HIV-HCV patients treated with LDV/SOF show significant improvement of their health-related quality of life and other patient-reported outcomes during treatment and after treatment cessation.

Interleukin 28B polymorphisms are the only common genetic variants associated with low-density lipoprotein cholesterol (LDL-C) in genotype-1 chronic hepatitis C and determine the association between LDL-C and treatment response

Low-density lipoprotein cholesterol (LDL-C) levels and interleukin 28B (IL28B) polymorphism are associated with sustained viral response (SVR) to peginterferon/ribavirin (pegIFN/RBV) for chronic hepatitis C (CHC) infection. IL28B has been linked with LDL-C levels using a candidate gene approach, but it is not known whether other genetic variants are associated with LDL-C, nor how these factors definitively affect SVR. We assessed genetic predictors of serum lipid and triglyceride levels in 1604 patients with genotype 1 (G1) chronic hepatitis C virus (HCV) infection by genome-wide association study and developed multivariable predictive models of SVR. IL28B polymorphisms were the only common genetic variants associated with pretreatment LDL-C level in Caucasians (rs12980275, P = 4.7 × 10(-17), poor response IL28B variants associated with lower LDL-C). The association was dependent on HCV infection, IL28B genotype was no longer associated with LDL-C in SVR patients after treatment, while the association remained significant in non-SVR patients (P < 0.001). LDL-C was significantly associated with SVR for heterozygous IL28B genotype patients (P < 0.001) but not for homozygous genotypes. SVR modelling suggested that IL28B heterozygotes with LDL-C > 130 mg/dL and HCV RNA ≤600 000 IU/mL may anticipate cure rates >80%, while the absence of these two criteria was associated with an SVR rate of <35%. IL28B polymorphisms are the only common genetic variants associated with pretreatment LDL-C in G1-HCV. LDL-C remains significantly associated with SVR for heterozygous IL28B genotype patients, where LDL-C and HCV RNA burden may identify those patients with high or low likelihood of cure with pegIFN/RBV therapy.

Elevated serum CK18 levels in chronic hepatitis C patients are associated with advanced fibrosis but not steatosis

Cytokeratin-18 (CK-18) is a major intermediate filament protein in liver cells. The M30 fragment of CK-18 has been identified as a useful marker of apoptosis associated with fibrosis and steatosis in nonalcoholic steatohepatitis (NASH). We sought to assess the relationship of this marker and steatosis in a cohort of adult patients with chronic hepatitis C. The study cohort included sera from 267 treatment-naïve chronic hepatitis C (CHC) patients and 100 healthy controls with normal alanine aminotransferase (ALT). Biopsies from CHC patients were assessed for METAVIR fibrosis stage, Histology Activity Index (HAI) inflammation score and steatosis grade by expert histopathologists. The M30 fragment of CK-18 was quantified by ELISA. Wilcoxon Rank Sum, Spearman Correlation and Linear Regression tests were performed for statistical analysis. Median CK-18 levels were higher in CHC patients compared to controls (411 vs 196 U/L, P < 0.0001). Fibrosis stage was associated with increasing serum CK-18 levels (P = 0.015) and CK-18 levels were higher for F2-F4 vs F0-F1 (500 vs 344 U/L; P = 0.001). There was no association between CK-18 and increasing steatosis grade 1, 2 or 3 (460.7 vs 416.8 vs 508.3 U/L; P = 0.35) and presence or absence of steatosis (445.3 vs 365.8 U/L; P = 0.075). Fibrosis stage was independently associated with serum M30 in a multivariable linear regression model (P = 0.03). CK-18 levels were higher in CHC compared to healthy controls and associated with hepatic fibrosis. There was no difference in CK-18 M30 levels between CHC patients with and without steatosis. Although apoptosis may still contribute to hepatitis C virus (HCV)-mediated steatosis, our results suggest that serum CK-18 will not be a clinically useful test for identifying significant steatosis in CHC.

Human interleukin-2 production in insect (Trichoplusia ni) larvae: effects and partial control of proteolysis

Many eukaryotic proteins have been successfully expressed in insect cells infected with a baculovirus in which the foreign gene has been placed under the control of a viral promoter. This system can be costly at large scale due to the quality of virus stock, problems of oxygen transfer, and severity of large-scale contamination. To circumvent this problem, we have investigated the expression of a foreign protein, human interleukin-2 (IL-2), in insect larvae, Trichoplusia ni, infected with the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV). The IL-2 gene was placed under control of the p10 promoter so that the polyhedra remained intact for efficient primary infection. From our results, it was clear that early infection limited larval growth and late infection delayed product production until near pupation, hence infection timing was important. Also, the harvest time was crucial for obtaining high yield, because IL-2 production had a sharp optimal peak with a time of occurrence dependent on both temperature and the initial amount of infection virus. Specifically, we found that, by raising the infection temperature to 30 degrees C, we more than doubled the protein productivity. Furthermore, a significant concern of the larvae/baculovirus expression system has been the large amount of protease produced by the larvae, which adversely affects the protein yield. Therefore, we screened several protease inhibitors and characterized the larval protease specificity and timing to attenuate their impact. This report elucidates and delineates the factors that most directly impact protein yield in the larvae expression system, using IL-2 as a model.

Appearance of protease activities coincides with p10 and polyhedrin-driven protein production in the baculovirus expression system: effects on yield

A study of proteolysis effects on recombinant protein yield was completed using the insect cell (Sf-9)-baculovirus (AcNPV) expression system. Activities of protease and beta-galactosidase (beta-gal), a marker heterologous protein, were assayed at various multiplicities of infection (MOI = 1, 5, and 20) on a time course postinfection. Also, several protein-substrate gel electrophoresis assays were run using gelatin, beta-gal, and bovine serum albumin (BSA) in the gel matrix, to determine the protein specificity of the proteases. The most abundant protease activity (cysteine), found at 49 kDa, degraded all three substrates, pre- and post-infection. Two other protease activities (40 and 36 kDa) appeared on polyacrylamide gel electrophoresis (PAGE) gels after 72 hpi (hours postinfection). In addition, the culture with the highest MOI had the highest beta-gal activity until 72 hpi, when the activity dramatically decreased coincidentally with a 2.5-fold increase in protease activity. This result and the electrophoresis evidence that the protease is specific to beta-gal, indicate that there is a negative correlation between protease activity and recombinant protein yield. These results guide efforts to control product-degrading proteolysis in insect cell-baculovirus expression systems by harvest timing and the addition of protease inhibitors.