Presence of hepatitis C virus (HCV) genomic RNA and viral replicative intermediates in bone marrow and peripheral blood mononuclear cells from HCV-infected patients

Proteomics reveals a global phenotypic shift of NK cells in HCV patients treated with direct-acting antivirals

Chronic hepatitis C virus (HCV) infections compromise natural killer (NK)-cell immunity. Direct-acting antivirals (DAA) effectively eliminate HCV, but the long-term effects on NK cells in cured patients are debated. We conducted a proteomic study on CD56+ NK cells of chronic HCV-infected patients before and 1 year after DAA therapy. Donor-variation was observed in NK-cell proteomes of HCV-infected patients, with 46 dysregulated proteins restored after DAA therapy. However, 30% of the CD56+ NK-cell proteome remained altered 1 year post-therapy, indicating a phenotypic shift with low donor-variation. NK cells from virus-negative cured patients exhibited global regulation of RNA-processing and pathways related to "stimuli response", "chemokine signaling", and "cytotoxicity regulation". Proteomics identified downregulation of vesicle transport components (CD107a, COPI/II complexes) and altered receptor expression profiles, indicating an inhibited NK-cell phenotype. Yet, activated NK cells from HCV patients before and after therapy effectively upregulated IFN-γ and recruited CD107a. Conversely, reduced surface expression levels of Tim-3 and 2B4 were observed before and after therapy. In conclusion, this study reveals long-term effects on the CD56+ NK-cell compartment in convalescent HCV patients 1 year after therapy, with limited abundance of vesicle transport complexes and surface receptors, associated with a responsive NK-cell phenotype.

MicroRNA 122 Affects both the Initiation and the Maintenance of Hepatitis C Virus Infections

A liver-specific microRNA, miR-122, anneals to the hepatitis C virus (HCV) genomic 5' terminus and is essential for virus replication in cell culture. However, bicistronic HCV replicons and full-length RNAs with specific mutations in the 5' untranslated region (UTR) can replicate, albeit to low levels, without miR-122. In this study, we have identified that HCV RNAs lacking the structural gene region or having encephalomyocarditis virus internal ribosomal entry site (EMCV IRES)-regulated translation had reduced requirements for miR-122. In addition, we found that a smaller proportion of cells supported miR-122-independent replication compared a population of cells supporting miR-122-dependent replication, while viral protein levels per positive cell were similar. Further, the proportion of cells supporting miR-122-independent replication increased with the amount of viral RNA delivered, suggesting that establishment of miR-122-independent replication in a cell is affected by the amount of viral RNA delivered. HCV RNAs replicating independently of miR-122 were not affected by supplementation with miR-122, suggesting that miR-122 is not essential for maintenance of an miR-122-independent HCV infection. However, miR-122 supplementation had a small positive impact on miR-122-dependent replication, suggesting a minor role in enhancing ongoing virus RNA accumulation. We suggest that miR-122 functions primarily to initiate an HCV infection but has a minor influence on its maintenance, and we present a model in which miR-122 is required for replication complex formation at the beginning of an infection and also supports new replication complex formation during ongoing infection and after infected cell division. IMPORTANCE The mechanism by which miR-122 promotes the HCV life cycle is not well understood, and a role in directly promoting genome amplification is still debated. In this study, we have shown that miR-122 increases the rate of viral RNA accumulation and promotes the establishment of an HCV infection in a greater number of cells than in the absence of miR-122. However, we also confirm a minor role in promoting ongoing virus replication and propose a role in the initiation of new replication complexes throughout a virus infection. This study has implications for the use of anti-miR-122 as a potential HCV therapy.

Impact of Hepatitis C Virus Infection of Peripheral Blood Mononuclear Cells on the Immune System

Hepatitis C is a worldwide liver disease caused by hepatitis C virus (HCV) infection. The virus causes acute and chronic liver inflammation, and it is transmitted mainly by exposure to contaminated blood. HCV is capable of infecting hepatocytes and peripheral blood mononuclear cells, causing complications and disease progression. This mini review provides an overview of HCV infection, including details on the virological aspects, infection of the immune cells, and its impact on the immune system.

Heterogeneity and coexistence of oncogenic mechanisms involved in HCV-associated B-cell lymphomas

The association of HCV-infection with B-lymphomas is supported by the regression of most indolent/low-grade lymphomas following anti-viral therapy. Studies on direct and indirect oncogenic mechanisms have elucidated the pathogenesis of HCV-associated B-lymphoma subtypes. These include B-lymphocyte proliferation and sustained clonal expansion by HCV-envelope protein stimulation of B-cell receptors, and prolonged HCV-infected B-cell growth by overexpression of an anti-apoptotic BCL-2 oncogene caused by the increased frequency of t(14;18) chromosomal translocations in follicular lymphomas. HCV has been implicated in lymphomagenesis by a "hit-and-run" mechanism, inducing enhanced mutation rate in immunoglobulins and anti-oncogenes favoring immune escape, due to permanent genetic damage by double-strand DNA-breaks. More direct oncogenic mechanisms have been identified in cytokines and chemokines in relation to NS3 and Core expression, particularly in diffuse large B-cell lymphoma. By reviewing genetic alterations and disrupted signaling pathways, we intend to highlight how mutually non-contrasting mechanisms cooperate with environmental factors toward progression of HCV-lymphoma.

Mother-to-child transmission of hepatitis C virus

This review reinforces the lack of a single maternal risk factor that is highly associated with vertical transmission (VT) of the infection with hepatitis C virus (HCV): indeed HCV RNA levels, mode of delivery, breast feeding, viral genotype or maternal IL28B status were not associated with HCV VT.

Increased Spontaneous Programmed Cell Death Is Associated with Impaired Cytokine Secretion in Peripheral Blood Mononuclear Cells from Hepatitis C Virus-Positive Patients

Peripheral blood mononuclear cells (PBMCs) play a critical role in clearing hepatitis C virus (HCV). PBMC defects have been linked with HCV infection; however, the underlying mechanisms remain obscure. We hypothesized that PBMCs of HCV-infected patients are more susceptible to programmed cell death (PCD), and are therefore unable to clear HCV. We compared spontaneous PBMC PCD and cytokine [interleukin (IL)-1, -6, -8, -10, and -12] secretion between untreated (naive) HCV⁺ and treated [sustained responder (SR)] patients with HCV, and HCV^- healthy controls. Spontaneous PBMC PCD was assessed by annexin-V fluorescein isothiocyanate/propidium iodide staining, and cytokine levels were measured by cytometric bead array. Differences between groups were analyzed through paired and nonpaired t tests and Mann-Whitney U test. The rate of spontaneous PCD was higher in PBMCs of naive HCV⁺ patients (p < 0.0001) and SR-HCV patients (p < 0.002) than in HCV^- controls. Significantly low levels of IL-8, -6, and -10 were detected in the supernatant of cell cultures of PBMCs from naive HCV⁺ (p < 0.05) and SR-HCV (p < 0.05) patients relative to HCV^- controls. There was no difference between the naive HCV⁺ and SR-HCV groups in terms of PBMC PCD rate or cytokine levels. The present findings indicate that HCV infection is associated with increased PBMC susceptibility to PCD and decreased production of IL-8, -6, and -10.

Extra-hepatic infection of hepatitis C virus in the colon tissue and its relationship with hepatitis C virus pathogenesis

Extra-hepatic compartments might contribute to hepatitis C virus (HCV) persistence and extra-hepatic manifestations. Therefore, we investigated HCV infection in colonic tissue in patients with chronic hepatitis C (CHC) and its relationship with HCV pathogenesis. Colonic biopsies were collected from three groups with CHC infection: treatment naïve (TN; n=12), non-responders (NR; n=10) to anti-HCV therapy (pegylated interferon-α and ribavirin) and sustained virologic response (SVR; n=10) and from a fourth healthy control group (n=10). Liver biopsies were examined to assess inflammation and fibrosis. HCV infection and colonic T regulatory (Treg) frequency were detected by immunohistochemistry. HCV core and NS3 proteins were detected in B cells and macrophage/monocytes of 42 % and 25 % of TN and 50 % and 30 % of NR, respectively, but not in SVR or control group. The numbers of cells expressing HCV proteins were positively correlated with both HCV viral load and colonic Treg frequency. A significant negative correlation between HCV-expressing cells with both liver inflammation and fibrosis was identified. Our study provides evidence that HCV can infect B cells and macrophages of the colon. The correlations between HCV infection in colonic tissue and HCV viral load and liver pathology underline the significance of this extra-hepatic infection in HCV pathogenesis and response to therapy.

Increased DNA damage in hepatitis C virus-related hepatocellular carcinoma

One consequence of hepatitis C virus (HCV) infection is an elevated cancer risk. During chronic viral infection, deoxyribonucleic acid (DNA) damage is being induced by reactive oxygen and nitrogen species, which may play a pathogenic role in HCV-induced carcinogenesis. The study investigated DNA damage in peripheral blood lymphocytes from patients with hepatocellular carcinoma (HCC) and those with HCV infection with and without associated cirrhosis and normal controls. As a measure for genomic damage, the comet assay (single cell gel electrophoresis) was applied, which detects single- and double-strand breaks and alkali-labile sites through electrophoretic mobility of the resulting fragments. The levels of DNA damage were significantly higher in HCC and HCV-associated cirrhosis compared to HCV without cirrhosis and the control group. Patients presenting with DNA damage more than mean+two standard deviation of the controls had a 3.6-fold risk of having HCC more than those with undamaged DNA. HCV disease progression was the only discriminator predicting the extent of DNA damage. The accumulation of DNA damage is important in HCC evolution. DNA damage indicating intracellular oxidative and nitrative stress may lead to mutagenesis and consequently malignant transformation, which emphasizes the need to optimize the therapy for reducing the degree of genomic damage.

Severe neutropenia in patients with chronic hepatitis C: a benign condition

BACKGROUND/AIMS

Patients with chronic hepatitis C virus (HCV) infection may develop neutropenia, which can delay or prevent treatment. Severe neutropenia, absolute neutrophil counts (ANC) ≤0.500 × 10(9)/l, is a rare finding, with only two isolated reports published in the literature. The aim of this study was to evaluate the incidence and natural history of severe neutropenia in hepatitis C patients.

METHODS

The records of 685 patients with active HCV were reviewed to identify those with severe neutropenia. The laboratory parameters and clinical history data of patients with severe neutropenia were then compared to a cohort of patients with HCV patients who had the more common minor neutropenia (ANC = 1.000-1.500 10(9)/l).

RESULTS

There was no significant difference in race, MELD (Model for End Stage Liver Disease) scores, portal hypertension, splenomegaly, viral load, viral type, or hemoglobin or platelet levels. Neither group suffered serious systemic infections.

CONCLUSIONS

Severe neutropenia in HCV patients is underreported and not associated with serious HCV complications such as elevated MELD score or cirrhosis. Serious infection is rare and patients respond well to granulocyte colony-stimulating factor. Severely neutropenic patients with HCV appear to have a benign course and may be candidates for antiviral therapy.

Human cell types important for hepatitis C virus replication in vivo and in vitro: old assertions and current evidence

Hepatitis C Virus (HCV) is a single stranded RNA virus which produces negative strand RNA as a replicative intermediate. We analyzed 75 RT-PCR studies that tested for negative strand HCV RNA in liver and other human tissues. 85% of the studies that investigated extrahepatic replication of HCV found one or more samples positive for replicative RNA. Studies using in situ hybridization, immunofluorescence, immunohistochemistry, and quasispecies analysis also demonstrated the presence of replicating HCV in various extrahepatic human tissues, and provide evidence that HCV replicates in macrophages, B cells, T cells, and other extrahepatic tissues. We also analyzed both short term and long term in vitro systems used to culture HCV. These systems vary in their purposes and methods, but long term culturing of HCV in B cells, T cells, and other cell types has been used to analyze replication. It is therefore now possible to study HIV-HCV co-infections and HCV replication in vitro.

Hepatitis C virus core protein up-regulates anergy-related genes and a new set of genes, which affects T cell homeostasis

Hepatitis C virus (HCV) infection is the main cause for chronic hepatitis, leading to cirrhosis and hepatic carcinoma. Virally induced immune dysfunction has been called as the cause for viral persistence. Previous results demonstrate that CD4 Jurkat cells stably expressing the HCV core protein show an increased activation of NFAT transcription factor and an impaired IL-2 promoter activity, affecting intracellular signaling pathways in a manner that mimics clonal anergy. We had shown previously that NFAT activates a transcriptional program, ensuing in immunological tolerance. In the present work, we have engineered lentiviral vectors expressing the HCV core to analyze the events, which unfold in the initial phase of HCV core-induced anergy. We show that genes initially described to be up-regulated by ionomycin-induced anergy in mice are also up-regulated in humans, not only by ionomycin but also by HCV core expression. We also show that HCV core is sufficient to cause NFAT nuclear translocation and a slow-down in cell-cycle progression, and using whole genome microarrays, we identify novel genes up-regulated in Jurkat cells expressing HCV core. The relevance of our results is highlighted by the presence of HCV in CD4 T cells from HCV chronically infected patients.

Compartmentalization of hepatitis C virus quasispecies in blood mononuclear cells of patients with mixed cryoglobulinemic syndrome

The aim of this study was to investigate the quasispecies heterogeneity of hepatitis C virus (HCV) in the plasma, cryoprecipitate, and peripheral lymphocytes of chronically infected HCV patients with mixed cryoglobulinemia (MC). We studied 360 clones from 10 HCV-positive patients with MC and 8 age-, gender- and HCV genotype-matched subjects with chronic HCV infection but without MC. A partial nucleotide sequence encompassing the E1/E2 region, including hypervariable region 1 (HVR1), was amplified and cloned from plasma, cryoprecipitates, and peripheral blood mononuclear cells (PBMC), and the genetic diversity and complexity and synonymous and nonsynonymous substitution rates were determined. Heterogeneous selection pressure at codon sites was evaluated. Compartmentalization was estimated by phylogenetic and phenetic (Mantel's test) approaches. The patients with MC had 3.3 times lower nonsynonymous substitution rates (1.7 versus 5.7 substitutions/100 sites). Among the subjects with HCV genotype 1, the MC patients had significantly less complexity than the controls, whereas the diversity and complexity were similar in the genotype 2 patients and controls. Site-specific selection analysis confirmed the low frequency of MC patients showing positive selection. There was a significant correlation between positive selection and the infecting HCV genotype. The quasispecies were less heterogeneous in PBMC than in plasma. Significant compartmentalization of HCV quasispecies was observed in the PBMC of four of nine subjects (three with MC) and seven of nine cryoprecipitates. In one subject with MC, we detected a 5-amino-acid insertion at codons 385 to 389 of HVR1. Our results suggest reduced quasispecies heterogeneity in MC patients that is related to a low selection pressure which is probably due to an impaired immune response, the HCV genotype, and/or the duration of the infection. The frequent HCV quasispecies compartmentalization in patients' PBMC suggests a possible pathogenetic significance.

Hepatitis C virus replicates in peripheral blood mononuclear cells of patients with occult hepatitis C virus infection

BACKGROUND

Occult hepatitis C virus (HCV) infection is characterised by the presence of HCV-RNA in the liver in the absence of anti-HCV, and serum viral RNA. Up to 70% of these patients also have HCV-RNA in peripheral blood mononuclear cells (PBMC) but it is not known if HCV is replicating in these cells.

AIM

We studied possible HCV replication in PBMC of 18 patients with an occult HCV infection who were selected on the basis of HCV-RNA positivity in PBMC.

METHODS

Detection of HCV-RNA positive and negative strands in PBMC was done by strand specific reverse transcriptase-polymerase chain reaction (RT-PCR) and by in situ hybridisation.

RESULTS

The presence of HCV-RNA positive strand in PBMC was confirmed in all patients by strand specific RT-PCR and by in situ hybridisation. Mean percentage of PBMC which had the HCV-RNA positive strand was 3.3% (95% confidence interval (CI) 2.1-4.4) The HCV-RNA negative strand was found in the PBMC of 11/18 (61%) patients by strand specific RT-PCR and confirmed by in situ hybridisation, and the percentage of PBMC harbouring the HCV-RNA negative strand was 3.1% (95% CI 0.8-5.5). There was a significant correlation (p = 0.001, r = 0.84) between the percentage of PBMC with the HCV-RNA positive strand and that of PBMC with the HCV-RNA negative strand.

CONCLUSION

HCV replicates in the PBMC of patients with occult HCV infection and thus, although these patients do not have serum HCV-RNA, they could be potentially infectious.

Therapies for HIV and viral hepatitis coinfection

The natural history of chronic viral hepatitis is altered by HIV coinfection. Liver fibrosis rates and clinical features of liver disease develop more rapidly. Although HIV-hepatitis C virus coinfected subjects may progress more rapidly to AIDS, this is probably explained by comorbid illness, substance abuse and socioeconomic circumstances. Safe and virologically active treatment of HIV-hepatitis B virus coinfection can be concurrently achieved by the use of highly active antiretroviral therapy regimens containing lamivudine and/or tenofovir. In most cases, highly active antiretroviral therapy represents the most beneficial initial pharmaceutical intervention for HIV-hepatitisC virus coinfection. HepatitisC virus antiviral therapy should, in most cases, be reserved for those achieving HIV RNA suppression and immune restoration from highly active antiretroviral therapy or with nadir CD4 T-lymphocytes above 350 cells/microl.

Detection of HCV-RNA in Cerumen of Chronically HCV-Infected Patients

OBJECTIVES/HYPOTHESIS

Viral hepatitis C is a worldwide public health problem. Hepatitis C virus is mainly transmitted by parenteral or percutaneous route. Nonparenteral transmission, such as through sexual activity, household contact, and vertical or perinatal exposure to body fluids or secretions, can occur, which has been studied before. Cerumen, however, has not been investigated for its ability to transmit hepatitis C virus. The aim of this study is to evaluate the importance of cerumen in transmission of hepatitis C virus infection.

STUDY DESIGN

This study was performed on 35 patients with confirmed chronic hepatitis C virus infection.

METHODS

Thirty-five cerumen specimens collected from the patients with hepatitis C virus RNA in their sera were prospectively analyzed for the presence of hepatitis C virus RNA by polymerase chain reaction.

RESULTS

None of the 35 cerumen specimens were positive for hepatitis C virus RNA.

CONCLUSION

This study showed that cerumen has no risk for transmission of hepatitis C virus infection, even in patients with high hepatitis C virus RNA serum levels; however, standard infection control precautions should be applied carefully in all examinations and surgical operations of the ears.

Clinical Response of Antilymphocyte Globulin-Based Treatment in Patients in Taiwan with Aplastic Anemia: Positive Hepatitis C Antibody May Represent a Response Predictor

Immunosuppression (IS) therapy with antilymphocyte globulin (ALG) is currently the treatment of choice for patients with aplastic anemia who do not have histocompatible sibling donors or who are not candidates for allogeneic bone marrow transplantation. Thirty-eight patients with aplastic anemia who received ALG-based therapy at a single institute in Taiwan were analyzed, and 28 were followed up for more than 6 months. Four patients (10.5%) had a complete response, and 11 (28.9%) had a partial response. The overall response rate was 39.4%. The significant prognostic factor that affected the response to IS therapy was a positive test result for antibodies to the hepatitis C virus. The rate of early mortality (death within 90 days after initiation of ALG-based therapy) was 15.8%, and most deaths were secondary to infection. Factors influencing the risk of early mortality were old age, hypotension, and bacteremia. In conclusion, ALG-based IS therapy was effective for aplastic anemia in Chinese patients. The role of hepatitis C associated with aplastic anemia and its relationship to IS need to be clarified by further investigations.

Expansion of innate CD5pos B cells expressing high levels of CD81 in hepatitis C virus infected liver

BACKGROUND/AIMS

Association of hepatitis C virus (HCV) with increased autoantibodies, mixed cryoglobulinaemia, non-Hodgkin's B-cell lymphoma and increased peripheral innate (CD5(pos)) B cells suggests a role for B-lymphocytes in the pathogenesis of HCV-infection.

METHODS

Flow cytometry was used to estimate CD5(pos) B cell levels and CD81 co-expression in chronic HCV infection. Viral load was assessed using PCR.

RESULTS

We demonstrate expansion of innate B cells in HCV-infected liver from patients with fibrosis score less than stage II (39%, % of total B cells, P=0.002) and end stage HCV cirrhosis (20%, P<0.05) compared with normal liver (8%). Expression of CD81, a signal transducing molecule and putative HCV receptor, was significantly increased on peripheral blood CD5(pos) B cells compared with conventional B cells (P=0.0001). Higher levels of CD81 on CD5(pos) B cells were more dramatic in the liver of HCV-infected individuals. However, no significant difference was observed in the viral load of CD5(pos)CD81(High) B cells and CD5(neg)CD81(Low) B cells.

CONCLUSIONS

Increased expression of CD81 on innate B cells, a population that is expanded in the livers and peripheral blood of chronic HCV-infected patients, suggests a role in viral specific activation and clonal proliferation in chronic HCV infection.

Dendritic cell susceptibility to hepatitis C virus genotype 1 infection

In vitro infection of human monocyte-derived dendritic cells was carried out to study their susceptibility to hepatitis C virus (HCV) infection. Immature dendritic cells and mature dendritic cells were incubated overnight at 37 degrees C with HCV-positive (genotype 1) serum samples; the presence of the viral genome associated with the production of its replicative intermediate was used as evidence of infection. In immature dendritic cells, HCV RNA was detectable from days 1-10 post-infection (p.i.), and de novo synthesis of negative-strand HCV RNA could be demonstrated by a strand-specific rTth reverse transcription-polymerase chain reaction at day 2. In mature dendritic cells, the positive-strand form was detectable from days 1-5 p.i., while the negative-strand HCV RNA appeared at days 1 and 2 p.i. Quasispecies present in the inoculum and 6 days p.i. were analyzed by sequencing hypervariable region 1 of the E2 protein. Only two of seven HVR variants present in the inoculum were found in HCV-infected immature dendritic cells. Another two HVR variants not found in the inoculum were recovered from infected immature dendritic cells, suggesting serum minor variants selection or virus evolution during in vitro replication. Analysis by single-strand conformation polymorphism assay of 5' untranslated region of HCV sequences showed that the patterns obtained from the inoculum and infected immature dendritic cells and mature dendritic cells differed slightly. These findings indicate that both immature dendritic cells and mature dendritic cells are susceptible to HCV genotype 1 infection, supporting at least HCV RNA replication. This model should be a valuable tool for the study of modulation of dendritic cell functions in HCV infection.

Clinical progression, survival, and immune recovery during antiretroviral therapy in patients with HIV-1 and hepatitis C virus coinfection: the Swiss HIV Cohort Study

BACKGROUND

Hepatitis C virus (HCV) infection is highly prevalent among HIV-1-infected individuals, but its contribution to the morbidity and mortality of coinfected patients who receive potent antiretroviral therapy is controversial. We used data from the ongoing Swiss HIV Cohort Study to analyse clinical progression of HIV-1, and the virological and immunological response to potent antiretroviral therapy in HIV-1-infected patients with or without concurrent HCV infection.

METHODS

We analysed prospective data on survival, clinical disease progression, suppression of HIV-1 replication, CD4-cell recovery, and frequency of changes in antiretroviral therapy according to HCV status in 3111 patients starting potent antiretroviral therapy.

RESULTS

1157 patients (37.2%) were coinfected with HCV, 1015 of whom (87.7%) had a history of intravenous drug use. In multivariate Cox's regression, the probability of progression to a new AIDS-defining clinical event or to death was independently associated with HCV seropositivity (hazard ratio 1.7 [95% CI 1.26-2.30]), and with active intravenous drug use (1.38 [1.02-1.88]). Virological response to antiretroviral therapy and the probability of treatment change were not associated with HCV serostatus. In contrast, HCV seropositivity was associated with a smaller CD4-cell recovery (hazard ratio for a CD4-cell count increase of at least 50 cells/microL=0.79 [0.72-0.87]).

INTERPRETATION

HCV and active intravenous drug use could be important factors in the morbidity and mortality among HIV-1-infected patients, possibly through impaired CD4-cell recovery in HCV seropositive patients receiving potent antiretroviral therapy. These findings are relevant for decisions about optimum timing for HCV treatment in the setting of HIV infection.

Relation between infection and autoimmunity in mixed cryoglobulinemia

Mixed cryoglobulinemia (MC) is a systemic vasculitis of small to medium-sized vessels due to the vascular deposition of circulating immune-complexes (CIC) and complement. A leukocytoclastic vasculitis is the histologic hallmark of cutaneous manifestations of the disease, while a clonal B lymphocyte expansion in blood, bone marrow, liver, and spleen represents the underlying pathologic alteration responsible for the production of cryo-CIC and non-cryo CIC with rheumatoid factor activity. A causative role of hepatitis C virus (HCV) infection has been demonstrated in the large majority of MC patients. Hepatitis C virus is both a hepatotropic and a lymphotropic virus; due to this latter biological peculiarity, HCV may trigger a constellation of autoimmune-lymphoproliferative disorders. Besides MC, other important HCV-related diseases are porphyria cutanea tarda, autoimmune hepatitis, membranoproliferative glomerulonephritis, and B cell neoplasias. Hepatitis C virus-related MC represents a link between autoimmune and lymphoproliferative disorders; moreover, MC is an important model to study the complex relation between infections and immune system alterations in humans. During the last years many other autoimmune manifestations have been correlated with HCV infection; namely, sicca syndrome, chronic polyarthritis, polydermatomyositis, fibromyalgia, autoimmune thyroiditis, lung fibrosis, and diabetes mellitus. It is often difficult to verify whether the above associations are coincidental or a pathogenetic link actually exists. At least for particular patients' subsets and in some geographic areas, a causative role of HCV seems to be likely. The geographically heterogeneous distribution of HCV-related autoimmune diseases suggests the contribution of important environmental and genetic factors in the pathogenesis of such conditions. In clinical practice, patients with recent-onset, atypical rheumatic and autoimmune disorders should be carefully investigated for possible HCV infection; this is particularly advisable for correct diagnosis and adequate therapeutic strategy.

Low risk of vertical transmission of hepatitis C virus by breast milk

To evaluate the risk of hepatitis C virus (HCV) transmission via breast milk, we collected 76 samples of breast milk from 73 chronically HCV-infected women and serum samples from their 76 perinatally HCV-exposed children. Enzyme immunoassay and strip immunoblot assay were used for detection of antibodies to HCV, and reverse transcriptase-polymerase chain reaction analysis was used for detection of HCV RNA. None of the 76 samples of breast milk contained HCV RNA, whereas 37 (59.7%) of 62 mothers tested for HCV RNA had HCV viremia. Only 1 of the 76 breast-fed infants had evidence of HCV infection. Because HCV infection in this child was detected 1 month after birth, it seems unlikely that it was transmitted by breast-feeding. These results indicate that HCV infection in pregnant women should not be a contra-indication for breast-feeding.

Dynamics of hepatitis C viremia after plasma exchange

BACKGROUND/AIMS

The dynamics of hepatitis C viremia after perturbation by plasma exchange was addressed in two infected patients with symptomatic cryoglobulinemia. This approach may offer an alternative to studying patients treated with antivirals in order to understand the dynamics of hepatitis C virion exchange among different compartments in vivo.

METHODS

Plasma exchange sessions were conducted every 24 h for 3 consecutive days; hepatitis C virus RNA copy numbers were evaluated in sequential plasma samples collected before (-24, -12, -8, and 0 h) and at short intervals (at 1, 3, 6, and 12 h) after each session.

RESULTS

After each plasma exchange session viremia dropped by 45.3-93.3% in patient 1, and by 60.5-72.7% in patient 2, paralleling (or, in some cases, exceeding) the amount of fluid exchanged. No mobilization of cell-free hepatitis C virus from extra-vascular sites was documented during the 2-h plasma exchange. The dynamics of hepatitis C viremia after each procedure was also evaluated. Pre-plasma exchange levels were restored within 3-6 h in both patients, and the mean doubling times of residual viremia were 4.6 h and 4.5 h for patients 1 and 2, respectively.

CONCLUSIONS

The results, in agreement with recent evidence indicating that the turnover of hepatitis C virions is a highly dynamic process, extend previous evaluations by documenting that large amounts of newly-produced virions are introduced into the vascular compartment within a few hours of the drop in hepatitis C viremia caused by plasma exchange.

Detection of hepatitis C virus RNA (HCV RNA) in amniotic fluid: a prospective study

BACKGROUND/AIMS

Mother-to-infant transmission of hepatitis C virus (HCV) has been reported, but the transmission route is unknown. The aim of our study was to detect HCV RNA in amniotic fluid of pregnant women seropositive for HCV.

METHODS

Twenty-two HCV seropositive women were included in the study (median age: 39 years). An amniocentesis was performed in all patients during the 4th month of pregnancy. Sixteen women also tested positive for HCV RNA in serum. The range of HCV RNA titers was 0.3 to 15.1x10(6) Eq/ml (Quantiplex HCV RNA 2.0 Assay, Chiron Diagnostics). Of these 16 viremic patients, four had an anterior placenta, ten had a posterior placenta and the position of the placenta was not determined in two cases. PCR (Amplicor HCV, Roche Diagnostics) was used to detect HCV RNA in the amniotic fluid. We also studied 11 HCV seronegative women as a control group.

RESULTS

In the viremic group (n = 16), HCV RNA was detected once in amniotic fluid. The positive specimen was collected from a patient with an HCV RNA serum value equal to 1.1x10(6) Eq/ml. The placenta was in an anterior position. A PCR inhibitor was detected in one case. No HCV RNA was detected in the amniotic fluid of six seropositive non-viremic patients, nor in the control group. Serum HCV RNA was negative in the ten children tested. The woman whose amniotic fluid contained HCV RNA was the mother of one of them.

CONCLUSIONS

HCV RNA detection in amniotic fluid is rarely positive. The anterior position of the placenta in the only positive detection cannot rule out contamination of the amniotic fluid during the transplacental amniocentesis.

Quantitation of hepatitis C virus RNA production in two human bone marrow-derived B-cell lines infected in vitro

The ability of hepatitis C virus (HCV) to replicate in two B-cell lines, CE and TOFE, derived from bone marrow of healthy subjects was compared using qualitative and quantitative molecular methods. The presence of intracellular negative-stranded HCV RNA (replicative intermediate) was investigated by nested polymerase chain reaction (PCR) in the infected cultures at different times after infection. The amounts of positive-stranded HCV RNA (genomic RNA copies) synthesized and released from cells one week after in vitro infection were determined by competitive PCR after reverse transcription of viral RNA for the 5' viral untranslated region. In both cell lines, HCV RNA replication took place, but the TOFE cell line appeared to be a more efficient virus producer than the CE cell line. The TOFE cell line could be a valuable and reliable tool for basic and clinical HCV studies.

Hepatitis C virus infection and mixed cryoglobulinaemia: assessment of HCV RNA copy numbers in supernatant, cryoprecipitate and non-liver cells

The aim of this study was to characterize hepatitis C virus (HCV) infection in patients with mixed cryoglobulinaemia (MC). The HCV RNA copy number was assayed in clinical specimens from 15 consecutive patients with MC and HCV infection. Absolute quantification of HCV RNA molecules was performed using a competitive reverse transcription-polymerase chain reaction (cRT-PCR). Specific HCV RNA sequences were detected and quantified in plasma samples from all patients (mean HCV RNA copy number 4.9 x 10(6) ml-1 plasma). A high concentration of HCV RNA molecules was detected in the cryoprecipitates of eight of the 15 patients, who had a cryoprecipitate/supernatant ratio higher than 3.0 (range 3.60 to 186.80): in the remaining seven patients this ratio was close to or lower than 1.0 (range 0.13 to 1.60). Quantitative analysis of HCV RNA molecules in cells other than hepatocytes (i.e. peripheral blood mononuclear cells (PBMCs) and bone marrow cells (BMCs), in which the HCV replicative intermediate was detected using strand specific RT-PCR, demonstrated that infection is detectable in nearly 60% of these extrahepatic cells. Quantitative analysis of HCV RNA in PBMCs and BMCs revealed low levels of viral nucleic acids.

Quantitation of hepatitis C virus genome molecules in plasma samples

A competitive reverse transcription PCR (cRT-PCR)-based assay for the quantitative detection of hepatitis C virus (HCV) viremia was developed, optimized, and applied to the direct molecular analysis of clinical samples from nine patients with persistent HCV infection. As for other competitive PCR-based applications, this method consists of the reverse transcription and subsequent amplification of two RNA species in the same tube: the wild-type template (to be quantified) and a known amount of a modified synthetic template. These templates have identical primer recognition sites and very similar (but not identical) sizes, thus allowing direct detection of both template species after gel electrophoresis and ethidium bromide staining. The results obtained by this cRT-PCR application for testing clinical samples from HCV-infected patients mainly indicate that the competitive approach reaches the degree of sensitivity (fewer than 5 HCV RNA molecules per 100 microliters) necessary to evaluate viral load in all HCV-infected patients, independently of clinical conditions, and that this technique is flexible enough to quantify highly divergent levels of cell-free HCV genome copy numbers in biological samples. Interestingly, we observed a sample-to-sample variation in the loss of detectable HCV genome molecules in serum in comparison with that in plasma from the same patient, thus indicating that serum specimens, although widely used in the past few years for qualitative molecular investigation of HCV-infected patients, cannot be used to obtain reliable quantitative data on HCV viremia from these patients.