Influence of GB virus C on IFN-γ and IL-2 production and CD38 expression in T lymphocytes from chronically HIV-infected and HIV-HCV-co-infected patients.

This study was designed to assess the effect of GB virus (GBV)-C on the immune response to human immunodeficiency virus (HIV) in chronically HIV-infected and HIV- hepatitis C virus (HCV)-co-infected patients undergoing antiretroviral therapy. A cohort of 159 HIV-seropositive patients, of whom 52 were HCV-co-infected, was included. Epidemiological data were collected and virological and immunological markers, including the production of interferon gamma (IFN-γ) and interleukin (IL)-2 by CD4, CD8 and Tγδ cells and the expression of the activation marker, CD38, were assessed. A total of 65 patients (40.8%) presented markers of GBV-C infection. The presence of GBV-C did not influence HIV and HCV replication or TCD4 and TCD8 cell counts. Immune responses, defined by IFN-γ and IL-2 production and CD38 expression did not differ among the groups. Our results suggest that neither GBV-C viremia nor the presence of E2 antibodies influence HIV and HCV viral replication or CD4 T cell counts in chronically infected patients. Furthermore, GBV-C did not influence cytokine production or CD38-driven immune activation among these patients. Although our results do not exclude a protective effect of GBV-C in early HIV disease, they demonstrate that this effect may not be present in chronically infected patients, who represent the majority of patients in outpatient clinics.

Gene expression profiling of mononuclear cells from patients with sepsis secondary to community-acquired pneumonia.

Mechanisms governing the inflammatory response during sepsis involve crosstalk between diverse signaling pathways, but current knowledge provides an incomplete picture of the syndrome. Microarray-based expression profiling is a powerful approach for the investigation of complex clinical conditions such as sepsis. In this study, we investigated whole-genome expression profiles in mononuclear cells from septic patients admitted in intensive care units with community-acquired pneumonia. Blood samples were collected at the time of sepsis diagnosis and seven days later since we aimed to evaluate the role of biological processes or genes possibly involved in patient recovery. Here we provide a detailed description of the study design, including clinical information, experimental methods and procedures regarding data analysis. Metadata corresponding to microarray results deposited in the database Gene Expression Omnibus (GEO) under the accession number GSE48080 are also described in this report. Our dataset allows the identification of genes possibly associated with host defense to infection as well as gene expression patterns associated with patient outcome.

Patterns of gene expression in peripheral blood mononuclear cells and outcomes from patients with sepsis secondary to community acquired pneumonia.

Mechanisms governing the inflammatory response during sepsis have been shown to be complex, involving cross-talk between diverse signaling pathways. Current knowledge regarding the mechanisms underlying sepsis provides an incomplete picture of the syndrome, justifying additional efforts to understand this condition. Microarray-based expression profiling is a powerful approach for the investigation of complex clinical conditions such as sepsis. In this study, we investigate whole-genome expression profiles in mononuclear cells from survivors (n = 5) and non-survivors (n = 5) of sepsis. To circumvent the heterogeneity of septic patients, only patients admitted with sepsis caused by community-acquired pneumonia were included. Blood samples were collected at the time of sepsis diagnosis and seven days later to evaluate the role of biological processes or genes possibly involved in patient recovery. Principal Components Analysis (PCA) profiling discriminated between patients with early sepsis and healthy individuals. Genes with differential expression were grouped according to Gene Ontology, and most genes related to immune defense were up-regulated in septic patients. Additionally, PCA in the early stage was able to distinguish survivors from non-survivors. Differences in oxidative phosphorylation seem to be associated with clinical outcome because significant differences in the expression profile of genes related to mitochondrial electron transport chain (ETC) I-V were observed between survivors and non-survivors at the time of patient enrollment. Global gene expression profiles after seven days of sepsis progression seem to reproduce, to a certain extent, patterns collected at the time of diagnosis. Gene expression profiles comparing admission and follow-up samples differed between survivors and non-survivors, with decreased expression of genes related to immune functions in non-survivors. In conclusion, genes related to host defense and inflammatory response ontology were up-regulated during sepsis, consistent with the need for a host response to infection, and the sustainability of their expression in follow-up samples was associated with outcomes.

Bacterial sensing, cell signaling, and modulation of the immune response during sepsis.

Since the definition of systemic inflammatory response syndrome/sepsis was originally proposed, a large amount of new information has been generated showing a much more complex scenario of inflammatory and counterinflammatory responses during sepsis. Moreover, some fundamental mechanisms of sensing and destroying invading microorganisms have been uncovered, which include the discovery of TLR4 as the lipopolysaccharide (LPS) gene, implications of innate immune cells as drivers of the adaptive response to infection, and the modulation of multiple accessory molecules that stimulate or inhibit monocyte/macrophage and lymphocyte interactions. The complexity of the infection/injury-induced immune response could be better appreciated with the application of genomics and proteomics studies, and LPS was a useful tool in many of these studies. In this review, we discuss aspects of bacterial recognition and induced cellular activation during sepsis. Because of the relevance of endotoxin (LPS) research in the field, we focus on LPS and host interactions as a clue to understand microorganisms sensing and cell signaling, then we discuss how this response is modulated in septic patients.

Differential expression of toll-like receptor signaling cascades in LPS-tolerant human peripheral blood mononuclear cells.

Pre-exposure to low doses of LPS induces resistance to a lethal challenge, a phenomenon known as endotoxin tolerance. In this study, tolerance was induced in human PBMC by culturing cells with 1 ng/mL LPS for 48 h. Cells were subsequently challenged with 100 ng/mL LPS for 2, 6 and 24 h, and the expression of 84 genes encoding proteins involved in the TLR signaling pathway was evaluated at each time point by PCR array. LPS pretreatment did not modulate the expression of TLR4 and CD14 on the surface of monocytes. A gene was defined as tolerized when LPS pretreatment reversed the effect of LPS challenge on the expression of the gene or as non-tolerized when LPS pretreatment did not reverse the effects of LPS challenge. We observed impaired signal transduction through the NF-κB, JNK, ERK and TRIF pathways, whereas expression of p38 pathway-related genes was preserved in LPS-tolerant cells. These results show a distinct regulation of the TLR pathway cascades during tolerance; this may account for the differential gene expression of some inflammatory mediators, such as up-regulation of IL-10 and COX2 as well as down-regulation of TNF-α and IL-12. Depending on the effect of LPS-induced gene up-regulation or down-regulation, tolerance, as a reversion of such LPS effects, may result in repression or induction of gene expression.

HIV-GB virus C co-infection: an overview.

GB virus C (GBV-C) and hepatitis G virus (HGV) are two isolates of the same virus, independently identified in humans in the 1990s by two research laboratories, and were initially considered a potential cause of liver disease. Studies failed to associate the virus with hepatitis or any known human disease. GBV-C reappeared in the scientific scene when some research groups, in an attempt to find the interference of the virus among HIV seropositive patients, reported a lower mortality rate and slower disease progression among co-infected patients. From then on, several mechanisms have been proposed to clarify this putative benefit; however, the question whether GBV-C exerts a protective effect in HIV-infected patients remains to be resolved.

Analysis of GB virus C infection among HIV-HCV coinfected patients.

The aim of this study was to evaluate the effect of GB virus C on laboratory markers and histological parameters among HIV-seropositive patients coinfected with HCV. Lower degrees of hepatic lesions were observed in the triple-infected patients, in comparison with HIV-HCV coinfected patients who were negative for GBV-C RNA.

Influence of GB virus C on IFN-γ and IL-2 production and CD38 expression in T lymphocytes from chronically HIV-infected and HIV-HCV-co-infected patients

This study was designed to assess the effect of GB virus (GBV)-C on the immune response to human immunodeficiency virus (HIV) in chronically HIV-infected and HIV- hepatitis C virus (HCV)-co-infected patients undergoing antiretroviral therapy. A cohort of 159 HIV-seropositive patients, of whom 52 were HCV-co-infected, was included. Epidemiological data were collected and virological and immunological markers, including the production of interferon gamma (IFN-γ) and interleukin (IL)-2 by CD4, CD8 and Tγδ cells and the expression of the activation marker, CD38, were assessed. A total of 65 patients (40.8 percent) presented markers of GBV-C infection. The presence of GBV-C did not influence HIV and HCV replication or TCD4 and TCD8 cell counts. Immune responses, defined by IFN-γ and IL-2 production and CD38 expression did not differ among the groups. Our results suggest that neither GBV-C viremia nor the presence of E2 antibodies influence HIV and HCV viral replication or CD4 T cell counts in chronically infected patients. Furthermore, GBV-C did not influence cytokine production or CD38-driven immune activation among these patients. Although our results do not exclude a protective effect of GBV-C in early HIV disease, they demonstrate that this effect may not be present in chronically infected patients, who represent the majority of patients in outpatient clinics.

Analysis of GB virus C infection among HIV-HCV coinfected patients / Análise da infecção pelo vírus GB-C em pacientes com coinfecção VIH-VHC

The aim of this study was to evaluate the effect of GB virus C on laboratory markers and histological parameters among HIV-seropositive patients coinfected with HCV. Lower degrees of hepatic lesions were observed in the triple-infected patients, in comparison with HIV-HCV coinfected patients who were negative for GBV-C RNA.

O objetivo do estudo foi avaliar o efeito da infecção pelo vírus GB-C em marcadores laboratoriais e parâmetros histológicos em pacientes HIV soropositivos coinfectados com VHC. Menor grau de lesão hepática foi observado nos pacientes com tripla infecção em comparação aos pacientes coinfectados com VIH-VHC negativos para GBV-C RNA.