Clearance of hepatitis C virus RNA from the peripheral blood mononuclear cells of blood donors who spontaneously or therapeutically control their plasma viremia

Chronic viral hepatitis is a significant contributor to the immunosenescent phenotype of parenteral drug addiction

Intravenous drug addiction is known to be associated with an inordinate morbidity and mortality. As our previous report had identified an immune phenotype consistent with accelerated ageing, we wished to investigate how much of this change may have been related to chronic viral hepatitis. A total of 12 409 clinical pathology results from the period 1995-2007 were reviewed. To control for the differences in age, only patients less than 48 years of age were considered. A total of 636 substance use disorder (SUD) and 6103 non-SUD (N-SUD) patients were studied. They had comparable ages (mean +/- SD 31.32 +/- 6.90 versus 31.57 +/- 9.23, P-value not significant), but the SUD group had more males (74.37% versus 53.20%, P < 0.001). For most of the changes examined splitting the two SUD groups into hepatitis C positive (HCV+) and hepatitis C negative (HCV-) demonstrated that the majority of the described changes were most marked in the HCV+ group. The globulins were higher in the HCV+ group and the albumin was lower and fell more markedly with age than in N-SUD or HCV- (all P < 0.001). The globulin/albumin ratio was significantly higher in HCV+ than HCV- or N-SUD (both P < 0.0001) and rose more with age. These changes were paralleled by the ESR, elevations in the CRP and lymphocyte count. Transaminases were elevated in SUD and HCV+ groups compared with N-SUD (all P < 0.02). At multivariate analysis ESR, lymphocyte count, dual hepatitis B and C seropositivity, AST and HCVAb were significant predictors of the serum globulin level and accounted for 21% of the variance. These data extend our earlier report and show that much of the immunosenescent phenotype of SUD, encompassing the known immunosuppression and the observed immunostimulation, is statistically related to chronic viral hepatitis. Important theoretical and practical management (vaccination) implications ensue.

Cell culture-produced hepatitis C virus does not infect peripheral blood mononuclear cells

Hepatitis C virus (HCV) replicates primarily in the liver, but HCV RNA has been observed in association with other tissues and cells including B and T lymphocytes, monocytes, and dendritic cells. We have taken advantage of a recently described, robust system that fully recapitulates HCV entry, replication and virus production in vitro to re-examine the issue of HCV infection of blood cell subsets. The HCV replicase inhibitor 2'C-methyl adenosine was used to distinguish HCV RNA replication from RNA persistence. Whereas cell culture-grown HCV replicated in Huh-7.5 hepatoma cells, no HCV replication was detected in B or T lymphocytes, monocytes, macrophages, or dendritic cells from healthy donors. No blood cell subset tested expressed significant levels of Claudin-1, a tight junction protein needed for HCV infection of Huh-7.5 cells. A B cell line expressing high levels of Claudin-1, CD81, and scavenger receptor BI remained resistant to HCV pseudoparticle infection. We bypassed the block in HCV entry by transfecting HCV RNA into blood cell subsets. Transfected RNA was not detectably translated and induced high levels of interferon-alpha. Supernatants from HCV RNA-transfected macrophages inhibited HCV replication in Huh-7.5 cells.

CONCLUSION

We conclude that multiple blocks prevent blood cells from supporting HCV infection.

Evidence for persistent low-level viremia in individuals who control human immunodeficiency virus in the absence of antiretroviral therapy

A subset of antiretroviral-untreated, human immunodeficiency virus (HIV)-infected individuals are able to maintain undetectable plasma HIV RNA levels in the absence of antiretroviral therapy. These "elite" controllers are of high interest as they may provide novel insights regarding host mechanisms of virus control. The degree to which these individuals have residual plasma viremia has not been well defined. We performed a longitudinal study of 46 elite controllers, defined as HIV-seropositive, antiretroviral-untreated individuals with plasma HIV RNA levels of <50 to 75 copies/ml. The median duration of HIV diagnosis was 13 years, the median baseline CD4(+) T-cell count was 753 cells/mm(3), and the median duration of follow-up was 16 months. Plasma and cellular HIV RNA levels were measured using the transcription-mediated amplification (TMA) assay (estimated limit of detection of <3.5 copies RNA/ml). A total of 1,117 TMA assays were performed (median of five time points/subject and four replicates/time point). All but one subject had detectable plasma HIV RNA on at least one time point, and 15 (33%) subjects had detectable RNA at all time points. The majority of controllers also had detectable cell-associated RNA and proviral DNA. A mixed-effect linear model showed no strong evidence of change in plasma RNA levels over time. In conclusion, the vast majority (98%) of elite controllers had measurable plasma HIV RNA, often at levels higher than that observed in antiretroviral-treated patients. This confirms the failure to eradicate the virus, even in these unique individuals who are able to reduce plasma viremia to very low levels without antiretroviral therapy.