Natural cytotoxicity receptor-dependent natural killer cytolytic activity directed at hepatitis C Virus (HCV) is associated with liver inflammation, African American race, IL28B genotype, and response to pegylated interferon/ribavirin therapy in chronic HCV infection.

Background: Natural killer (NK) cells are implicated in the pathogenesis of hepatitis C virus (HCV) infection and outcome of interferon (IFN)-α based therapy, although mechanisms remain unclear.

Methods: To evaluate NK ability to control HCV infection, we analyzed healthy donor and HCV-infected donor NK-cell cytolytic activity directed at HCV-infected target cells.

Results: HCV-infected subjects' natural cytotoxicity receptor (NCR)-dependent NK-cell cytolytic activity directed at HCV-infected and uninfected Huh7.

Plasma proteome analysis reveals overlapping, yet distinct mechanisms of immune activation in chronic HCV and HIV infections.

Background: HIV infection contributes to accelerated rates of progression of liver fibrosis during hepatitis C virus (HCV) infection, and HCV liver disease contributes to mortality during HIV infection. Although mechanisms underlying these interactions are not well known, soluble and cellular markers of immune activation associate with disease progression during both infections.

Methods: We identified proteins varying in expression across the plasma proteomes of subjects with untreated HIV infection, untreated HCV infection with low aspartate transaminase/platelet ratio index, untreated HCV infection with high aspartate transaminase/platelet ratio index, HIV-HCV coinfection, and controls.

Genetically associated CD16(+)56(-) natural killer cell interferon (IFN)-αR expression regulates signaling and is implicated in IFN-α-induced hepatitis C virus decline.

Background: Natural killer (NK) cells likely contribute to outcome of acute hepatitis C virus (HCV) infection and interferon (IFN)-induced control of chronic HCV infection. We previously observed IFN-αR and NKp30 expression associated with IFN-α-dependent NK cell activity.

Methods: Here, we examined CD16(+)56(-), CD16(+)56(+), and CD16(-)56(+) NK cell subset IFN-αR and NKp30 expression in relation to magnitude of HCV genotype 1 decrease during pegylated IFN-α plus ribavirin therapy.

Peripheral blood B cell subset skewing is associated with altered cell cycling and intrinsic resistance to apoptosis and reflects a state of immune activation in chronic hepatitis C virus infection.

Chronic hepatitis C virus (HCV) infection is associated with B cell activation, although underlying mechanisms are unclear. To investigate B cell regulation during HCV infection, we measured bulk B cell CpG and Staphylococcus aureus Cowan-induced IgG Ab-secreting cell (ASC) frequency, HCV and tetanus-specific ASC frequency, BCR- and CD40L-dependent CD80/CD86 expression, and activation of memory CD4 cells. Immature transitional, naive, resting memory, mature activated, tissue-like memory, and plasma B cell subset frequencies, cell cycling, and intrinsic apoptosis were quantified.