Hepatitis C-associated mixed cryoglobulinemic vasculitis induces differential gene expression in peripheral mononuclear cells.

This study examines the distinct gene expression profile of peripheral blood mononuclear cells from patients with chronic hepatitis C infection and mixed cryoglobulinemic (MC) vasculitis. Our DNA microarray analysis indicates that hepatitis C virus (HCV)-associated MC vasculitis is characterized by compromised neutrophil function, impaired chemotaxis, and increased interferon-stimulated gene (ISG) expression, contributing to overall MC pathogenesis and end-organ damage. Increased ISG expression is suggestive of an enhanced endogenous interferon gene signature. PBMC depletion assays demonstrate that this increased expression is likely due to an activation of monocytes and not a direct result of B cell expansion. Notably, this monocyte activation of ISG expression in HCV-associated MC vasculitis suggests a poor predictor status of interferon-based treatment. Further analysis of PBMC gene expression profiles before and after in vivo B cell depletion therapy is critical to completely understanding the mechanisms of MC vasculitis pathogenesis.

Gene expression profiles predict emergence of psychiatric adverse events in HIV/HCV-coinfected patients on interferon-based HCV therapy.

BACKGROUND: The efficacy of pegylated interferon-α and ribavirin (pegIFN/RBV) in the treatment of Hepatitis C infection is limited by psychiatric adverse effects (IFN-PE). Our study examined the ability of differential gene expression patterns before therapy to predict emergent IFN-PE among 28 HIV/HCV-coinfected patients treated with pegIFN-α2b/RBV. METHODS: Patients dually infected with HIV and HCV were evaluated at baseline and during treatment by board-certified psychiatrists who classified patients into 2 groups: those who developed IFN-PE and those who did not (IFN-NPE). Gene expression analysis (Affymetrix HG-U133A) was performed using peripheral blood mononuclear cells before and after initiation of treatment. Analysis of Variance, post hoc analysis based on pair-wise comparisons, and functional annotation analysis identified differentially expressed genes within and between groups. Prediction analysis for microarrays was used to test the predictive ability of selected genes. RESULTS: Twenty-four genes (16 upregulated and 8 downregulated) that were differentially expressed at baseline in patients who subsequently developed IFN-PE compared with the IFN-NPE group showed the ability to predict IFN-PE with an accuracy of 82%. In 16 patients with IFN-PE, 135 genes (117 upregulated; 18 downregulated) were significantly modulated after treatment. Of these, 10 genes have already been shown to be associated with neuropsychiatric illnesses and were significantly modulated only in patients who experienced IFN-PE. CONCLUSIONS: We describe a novel molecular diagnostic biomarker panel to predict emergent IFN-PE in HIV/HCV-coinfected patients undergoing pegIFN/RBV treatment, which may improve the identification of patients at greatest risk for IFN-PE and suggest candidate therapeutic targets for preventing or treating IFN-PE.

Twice-weekly pegylated interferon-α-2a and ribavirin results in superior viral kinetics in HIV/hepatitis C virus co-infected patients compared to standard therapy.

BACKGROUND: Hepatitis C virus (HCV)/HIV co-infected patients have more rapid progression of liver fibrosis and only modest cure rates (sustained virologic responses, SVRs) when compared to HCV monoinfected patients. METHOD: We compared the virologic responses of either twice-weekly peginterferon-α-2a 180 µg/week (for 4 weeks, followed by weekly dosing) or weekly peginterferon-α-2a 180 µg/week, and weight-based ribavirin (1-1.2 g/day), among HIV/HCV co-infected genotype-1 individuals. RESULTS: Patients receiving the investigational dosing had lower levels of HCV RNA at all time points after initiation of therapy. More patients on this arm achieved clinically relevant early virological responses at weeks 1, 2, 4, 12, and 24. The enhanced early virologic response observed with the investigational arm was associated with a higher induction of interferon-stimulated genes. This early double dose regimen also resulted in a rapid normalization of liver enzymes. Twice-weekly peginterferon-α-2a was associated with more frequent early virological responses with similar safety profiles when compared with standard therapy. CONCLUSION: Our results, when confirmed in larger randomized clinical trials, may provide a novel therapeutic approach to improve SVR among HIV/HCV co-infected patients, especially African-American patients.

HCV in peripheral blood mononuclear cells are predominantly carried on the surface of cells in HIV/HCV co-infected individuals.

HCV replication in extra-hepatic reservoirs has been suggested to occur in many tissues including PBMCs. A recent study showed evidence for compartmentalization and evolution of HCV in PBMCs. However, the cells that support HCV replication in PBMCs have not been identified. In this study we have fractionated the PBMC from HIV/HCV co-infected patients into T, monocytes, B and NK cells, and most of the HCV was located in CD3-cell fractions. Protease treatment of PBMCs to remove cell surface receptors resulted in the loss of HCV RNA suggesting that most of the HCV is present on the cell surface. PBMCs were treated by freeze-thaw nuclease method that would protect the HCV RNA in the virus but not the intracellular viral RNA. Data from this analysis support the conclusion that most of HCV is present on the cell surface. Even though the presence of minus strand RNA in PBMCs suggests that a low level HCV replication takes place within the PBMCs of HIV/HCV co-infected individuals, HCV in PBMC is present mainly on the surface of non-T cells, mostly on NK, monocytes and B cells. These results suggest a unique pathogenic role of NK, monocyte and B cells as carriers of HCV.

Proteome-wide anti-hepatitis C virus (HCV) and anti-HIV antibody profiling for predicting and monitoring the response to HCV therapy in HIV-coinfected patients.

We quantified antibody responses to the hepatitis C virus (HCV) proteome that are associated with sustained virologic response (SVR) in human immunodeficiency virus (HIV)/HCV-coinfected patients treated with pegylated interferon and ribavirin. Analysis of pre- and posttreatment samples revealed significant decreases in the combined anti-core, anti-E1, and anti-NS4 HCV antibody titers in those with SVRs but not in those who experienced relapse or who did not respond. Furthermore, anti-HIV p24 antibody titers inversely correlated with treatment response. These results suggest that profiling anti-HCV antibody is useful for monitoring HCV therapy, especially in discriminating between those who experience relapse and those who have SVRs at 48 weeks.

Impact of interferon-ribavirin treatment on hepatitis C virus (HCV) protease quasispecies diversity in HIV- and HCV-coinfected patients.

Patients with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) coinfection for whom prior treatment of HCV with interferon-ribavirin has failed may require subsequent treatment with new HCV protease inhibitors (PIs). We evaluated the diversity of HCV nonstructural protein 3 (NS3) in 26 HCV- and HIV-coinfected patients receiving stable antiretroviral therapy (ART) who were treated with interferon-ribavirin. Plasma HCV RNA clonal analysis was performed. There was greater baseline NS3 diversity in patients with nonresponse or relapse than in those with sustained virologic response. Interferon-ribavirin treatment did not result in significant changes in HCV protease gene diversity or significant HCV PI resistance mutations. The effect of prior interferon-ribavirin treatment on HCV NS3 will likely not impact HCV PI efficacy in HIV-coinfected patients receiving ART.

Multiple markers for melanoma progression regulated by DNA methylation: insights from transcriptomic studies.

The incidence of melanoma is increasing rapidly, with advanced lesions generally failing to respond to conventional chemotherapy. Here, we utilized DNA microarray-based gene expression profiling techniques to identify molecular determinants of melanoma progression within a unique panel of isogenic human melanoma cell lines. When a poorly tumorigenic cell line, derived from an early melanoma, was compared with two increasingly aggressive derivative cell lines, the expression of 66 genes was significantly changed. A similar pattern of differential gene expression was found with an independently derived metastatic cell line. We further examined these melanoma progression-associated genes via use of a tailored TaqMan Low Density Array (LDA), representing the majority of genes within our cohort of interest. Considerable concordance was seen between the transcriptomic profiles determined by DNA microarray and TaqMan LDA approaches. A range of novel markers were identified that correlated here with melanoma progression. Most notable was TSPY, a Y chromosome-specific gene that displayed extensive down-regulation in expression between the parental and derivative cell lines. Examination of a putative CpG island within the TSPY gene demonstrated that this region was hypermethylated in the derivative cell lines, as well as metastatic melanomas from male patients. Moreover, treatment of the derivative cell lines with the DNA methyltransferase inhibitor, 2'-deoxy-5-azacytidine (DAC), restored expression of the TSPY gene to levels comparable with that found in the parental cells. Additional DNA microarray studies uncovered a subset of 13 genes from the above-mentioned 66 gene cohort that displayed re-activation of expression following DAC treatment, including TSPY, CYBA and MT2A. DAC suppressed tumor cell growth in vitro. Moreover, systemic treatment of mice with DAC attenuated growth of melanoma xenografts, with consequent re-expression of TSPY mRNA. Overall, our data support the hypothesis that multiple genes are targeted, either directly or indirectly, by DNA hypermethylation during melanoma progression.