Hepatitis C virus infection of mononuclear cells from peripheral blood and liver infiltrates in chronically infected patients

The Severity of Depressive Symptoms as an Independent Predictor of Sustained Virological Response During Treatment of Hepatitis C With Pegylated Interferon-α2a and Oral Ribavirin

BACKGROUND

Sustained virological response (SVR) is the best indicator of successful therapy for hepatitis C virus (HCV) infection. Patients with chronic HCV infection treated with pegylated interferon-α and ribavirin (PEG-IFN-α/RBV) can achieve SVR 56% of the time.

OBJECTIVES

This study aimed to evaluate baseline predictors of SVR in patients treated with PEG-IFN-α/RBV for HCV chronic infection.

METHODS

A total of 101 patients receiving PEG-IFN-α/RBV for chronic HCV infection participated in the prospective cohort study. Symptoms of depression were assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS) before the treatment. The multivariate regression analysis was applied to determine predictors of SVR.

RESULTS

Of a total of 101 patients included, 99 patients reached the primary end point-24 weeks after completing treatment. After the initial analysis of probable predictive variables, the logistic analysis included age, sex, HCV genetic type, and MADRS score. The HCV genotype (odds ratio = 0.22 [confidence interval = 0.073-0.68, p = .008) and MADRS score (OR = 0.88 [confidence interval = 0.80-0.98), p = .013]) predicted an SVR outcome.

CONCLUSIONS

The severity of depressive symptoms before treatment and HCV genotype are independent predictors of SVR.

Immune modulation by the hepatitis C virus core protein

Hepatitis C virus (HCV) infection is currently the most important cause of chronic viral hepatitis in the world and one of the most frequent indications for liver transplantation. HCV uses different strategies to evade the innate and adaptive immune response, and this evasion plays a key role in determining viral persistence. Several HCV viral proteins have been described as immune modulators. In this review, we will focus on the effect of HCV nucleocapsid core protein in the function of immune cells and its correlation with the findings observed in HCV chronically infected patients. Effects on immune cell function related to both extracellular and intracellular HCV core localization will be considered. This review provides an updated perspective on the mechanisms involved in HCV evasion related to one single HCV protein, which could become a key tool in the development of new antiviral strategies able to control and/or eradicate HCV infection.

Virus-driven autoimmunity and lymphoproliferation: the example of HCV infection

HCV chronic infection is characterized by possible development of both hepatic and extrahepatic manifestations. The infection by this both hepatotropic and lymphotropic virus is responsible for polyoligoclonal B-lymphocyte expansion, leading to several immune-mediated disorders. Mixed cryoglobulinemia syndrome that in some cases may evolve to frank B-cell non-Hodgkin's lymphoma is the prototype of HCV-driven autoimmune and lymphoproliferative disorders. The HCV oncogenic potential has been suggested by several clinicoepidemiological and laboratory studies; it includes hepatocellular carcinoma, B-cell non-Hodgkin's lymphoma and papillary thyroid cancer. The definition HCV syndrome refers to the complex of HCV-driven diseases; these latter are characterized by heterogeneous geographical distribution, suggesting a role of other important genetic and/or environmental cofactors. The natural history of HCV syndrome is the result of a multifactorial and multistep pathogenetic process, which may evolve from mild manifestations to systemic autoimmune disorders, and less frequently to malignant neoplasias. The present updated review analyzes the clinical and pathogenetic aspects of the main HCV-associated diseases.

Presence of HCV RNA in peripheral blood mononuclear cells may predict patients response to interferon and ribavirin therapy

BACKGROUND AND OBJECTIVES

Hepatitis C virus (HCV) is considered a hepatotropic virus, but it can repli.cate in peripheral blood mononuclear cells (PBMCs), which influence the sustained virological response (SVR) of the patients, as well as relapse in successfully treated patients. The main objective of this study was to establish the importance of PBMC HCV RNA detection as a primary test to declare the patient as a responder, and the secondary objective was to investigate the risk of non-SVR or relapse in individuals who showed an end-of-treatment (ETR).

DESIGN AND SETTINGS

Blood samples were collected after the completion of 6 months of therapy, and they were collected 6 months after the completion of treatment.

PATIENTS AND METHODS

A total 103 patients infected with the 3a genotype of HCV and those who were treated with interferon-a-2b and ribavirin for 24 weeks were selected. HCV RNA in plasma of at the end of treatment and 6 months after the completion of treatment was determined with the help of quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Of the 103 patients, 74.8% (number [n]=77) were end-of-treatment responders, while 25.2% (n=26) were nonresponders. Seventy-seven responders were tested for HCV RNA in their PBMCs. The HCV RNA was detected in the PBMCs of 29 patients (37.7%). After 6 months of the end of treatment, 15 (19.5%) of 77 ETR patients showed virological relapse, while 62 (80.5%) patients attained SVR. Relapse appeared significantly more often in patients with HCV RNA in their PBMCs at the ETR stage when compared to the patients who did not have the viral RNA (34.5% versus 10.4%, respectively; R2=6.67, P=.01; odds ratio [OR]: 1.3; 95% confidence interval [CI]=1.032-1.811).

CONCLUSION

Patients with HCV RNA in their PBMCs after attaining an ETR are more likely to show relapse as compared to patients who are negative for viral RNA in PBMCs at the ETR stage.

Prevalence of occult hepatitis C virus in egyptian patients with chronic lymphoproliferative disorders

Background. Occult hepatitis C virus infection (OCI) was identified as a new form of Hepatitis C virus (HCV), characterized by undetectable HCV antibodies and HCV RNA in serum, while HCV RNA is detectable in liver and peripheral blood cells only. Aim. The aim of this study was to investigate the occurrence of OCI in Egyptian patients with lymphoproliferative disorders (LPDs) and to compare its prevalence with that of HCV in those patients. Subjects and Methods. The current study included 100 subjects, 50 of them were newly diagnosed cases having different lymphoproliferative disorders (patients group), and 50 were apparently healthy volunteers (controls group). HCV antibodies were detected by ELISA, HCV RNA was detected in serum and peripheral blood mononuclear cells (PBMCs) by reverse transcription polymerase chain reaction(RT-PCR), and HCV genotype was detected by INNO-LiPA. Results. OCI was detected in 20% of patients group, compared to only 4% OCI in controls group. HCV was detected in 26% of patients group with a slightly higher prevalence. There was a male predominance in both HCV and OCI. All HCV positive patients were genotype 4. Conclusion. Our data revealed occurrence of occult HCV infection in Egyptian LPD patients at a prevalence of 20% compared to 26% of HCV.

The hepatitis C virus infection as a systemic disease

Hepatitis C Virus (HCV) is a major health problem, infecting about 3 % of people worldwide and leading to liver as well as extrahepatic diseases. This justifies the definition of HCV infection as a systemic disease. Based on available data, the link between the virus and some of these extrahepatic disorders is certain, whereas for some others needs further confirmation. HCV-related lymphoproliferative disorders, ranging from benign, but pre-lymphomatous conditions, like mixed cryoglobulinemia, to frank lymphomas, represent the extrahepatic manifestations most closely related to HCV. The primary involvement of the liver and lymphatic system corresponds to the double viral tropism, being HCV able to infect both hepatic and lymphatic cells. Other HCV-associated disorders include renal, endocrine, dermatological, cardiovascular, rheumatologic and central nervous system diseases. On the whole, the HCV disease appears a very important, mainly hidden, public health problem leading to heavy direct and indirect costs. The possibility that HCV may be eradicated following antiviral therapy is important for both the therapeutic and preventive points of view, making the HCV disease an ideal model for pathogenetic studies.

Longitudinal analysis of the 5'UTR, E2-PePHD and NS5A-PKRBD genomic regions of hepatitis C virus genotype 1a in association with the response to peginterferon and ribavirin therapy in HIV-coinfected patients

BACKGROUND

The rate of non-response to pegylated interferon plus ribavirin (peg-IFN+RBV) in HCV/HIV coinfected patients is higher than in HCV-monoinfected patients. In this sense, the contribution of HCV genetic variability is unknown. The 5' untranslated (5'UTR), the nonstructural 5A (NS5A) and the second envelope (E2) HCV genomic regions have been implicated to peg-IFN therapy response. The proteins appear to block interferon (IFN)-induced RNA-dependent protein kinase (PKR) and the 5'UTR may influence the viral lymphotropism.

METHODS

We examined comparatively the pretreatment HCV variability between HIV coinfected and HCV monoinfected patients as well as assessed longitudinally the impact of peg-IFN+RBV on HCV variability when HIV is co-present. For this purpose, 15 HIV coinfected and 20 HCV monoinfected patients were compared. They were peg-IFN+RBV non-responders and infected with HCV 1a.

RESULTS

Irrespectively of the HIV-coexistence, at baseline the amino acid variation in the NS5A-related domains was significantly higher than in the E2-PePHD (p<0.001). The number of amino acid variations (mean±SD) at the NS5A-ISDR domain was higher among HCV/HIV patients than HCV-monoinfected ones (1.80±0.77 vs. 0.95±1.05; p=0.009) but such difference was slightly lower when comparing NS5A-PKRBD sequences (2.47±1.13 vs. 1.60±1.57; p=0.06). No differences were found at the E2-PePHD (0±0 vs. 0.2±0.4). At intra-HIV coinfected patient level, only minor (HCV genetic analysis) or no (HCV substitution rate and quasispecies heterogeneity) changes were observed during therapy (basal, 24h, 4weeks, and 12weeks).

CONCLUSIONS

Among HCV-1a/HIV coinfected and HCV-monoinfected peg-IFN+RBV non-responder patients, the HCV variability at the 5'UTR, E2-PePHD and NS5A-PKRBD/ISDR domains was mostly comparable exhibiting a low number of variations. Four well-defined amino acid substitutions in NS5A-ISDR domain appeared most frequently when HIV coexists. The interferon-based therapy did not exert any effect in the variation, selection or diversity in the above mentioned HCV regions that could influence clinical responsiveness to IFN therapy.

[Reactivation of tuberculosis during dual therapy with pegylated interferon and ribavirin for chronic hepatitis C]

Hepatitis C viral infection can be associated with other infectious diseases including viral and bacterial infections such as tuberculosis. Mycobacterium tuberculosis infection may be latent for many years and revealed during an immunodeficiency state. The responsibility of antiviral treatment in the reactivation of tuberculosis is controversial. We report two cases of tuberculous reactivation during bitherapy with pegylated interferon and ribavirin for chronic hepatitis C. A rapid viral response was obtained in both cases. Tuberculous reactivation occurred at 12 and 13 weeks of antiviral treatment, respectively. Tuberculosis involved urinary tract in one patient and lymph nodes in the other. Antituberculous treatment was given and antiviral treatment maintained. The outcome of tuberculosis was favourable and a sustained viral response was obtained for both patients.

B-cell clonality in the liver of hepatitis C virus-infected patients

AIM

The association of hepatitis C virus (HCV) infection with type II mixed cryoglobulinemia is well established, but the role of HCV in B-cell lymphoma remains controversial. In patients with HCV infection, B-cell clonal expansions have been detected in peripheral blood and bone marrow, and a high prevalence of B-cell non-Hodgkin's lymphomas has been documented. Liver biopsies in chronic HCV infection frequently show portal lymphoid infiltrates with features of B follicles, whose clonality has not yet been investigated. The object of this study was to determine the frequency of liver-infiltrating monoclonal B-cells in 40 patients with HCV infection.

METHODS

Eight hundred and forty-eight patients were studied prospectively, including 40 HCV-positive patients and 808 patients with chronic hepatitis B virus (HBV) infection. Immunohistochemical study for B- and T-cell markers was performed on the paraffin-embedded liver tissue sections. The clonality of lymphoid B-cells was tested using a polymerase chain reaction (PCR) approach designed to identify immunoglobulin heavy chain gene (IgH) rearrangements.

RESULTS

Liver-infiltrating monoclonal B-cells were detected in the liver for 4 (10%) of 40 HCV-positive patients but were present in only 3 (0.37%) of 808 liver biopsy specimens with chronic HBV infection. Chi-square testing showed that the monoclonal B-cells infiltration in the liver was more frequent in the HCV-infected patients (P = 0.000). A clonal IgH rearrangement was detected in 5 (71.4%) of 7 liver biopsy specimens with monoclonal B-cells infiltration. In 2 of 5 patients with both a clonal B-cell expansion and monoclonal B-cells infiltration in the liver, a definite B-cell malignancy was finally diagnosed.

CONCLUSION

Liver-infiltrating monoclonal B-cells are detected in the liver of patients with chronic HCV and HBV infection. A high percentage of patients with monoclonal B-cells infiltration and B-cell clonality in the liver were finally diagnosed as having a definite B-cell malignancy.

Clinical management of HIV/hepatitis C virus coinfection

PURPOSE

The purpose of this study was to review the current management of hepatitis C virus (HCV) in persons coinfected with HIV.

DATA SOURCES

Comprehensive review of current scientific literature derived from electronic databases, article bibliographies, and conference abstracts.

CONCLUSIONS

HCV treatment is feasible in the individual coinfected with HIV; however, therapy is complex and requires intensive monitoring and support to achieve the outcome of viral eradication. New strategies to improve HCV treatment rates, adherence to therapy, and virological response rates are needed in this patient population.

IMPLICATIONS FOR PRACTICE

Nurse practitioners are crucial to the management of the HIV/HCV-coinfected patient. This patient population requires detailed clinical monitoring, education, side effect management, and strategies to improve adherence to therapy.

Extrahepatic manifestations of hepatitis C virus infection

Hepatitis C virus may cause hepatic and extrahepatic diseases. Extrahepatic manifestations range from disorders for which a significant association with viral infection is supported by epidemiologic and pathogenetic data, to anecdotal observations without clear proof of causality. This article describes the diagnosis and treatment of these diseases.

Effect of chronic hepatitis C virus infection on inflammatory lipid mediators

BACKGROUND

Platelet-activating factor (PAF), a powerful phospholipid mediator of inflammation, is degraded by plasma PAF-acetyl-hydxolase (pPAF-AH), an enzyme which circulates in serum mainly in a complex with lipoproteins that confer its biological activity. Hepatitis C virus (HCV) is linked to lipoproteins in serum too. Reduced pPAF-AH activity was observed in several diseases, including systemic vasculitis.

AIM

To evaluate if chronic HCV infection could alter pPAF-AH physiological functions.

SUBJECTS

145 subjects were studied: 56 HCV- and 52 HBV-infected patients (pathologic controls); 37 healthy subjects (healthy controls).

METHODS

pPAF-AH activity, PAF and Apo B100 titers were determined in plasma; enzyme expression levels were evaluated in monocyte-derived macrophages. HCV-RNA was detected in plasma, peripheral blood mononuclear cells and liver samples.

RESULTS

HCV-infected patients showed an increase of PAF levels following a significant decrease of pPAF-AH activity. A recovery of pPAF-AH activity occurs only in patients who clear HCV after the antiviral treatment. Expression levels of pPAF-AH mRNA and Apo B100 titers were not modified in HCV patients in comparison to controls.

CONCLUSION

In light of these results, it is tempting to hypothesize that during chronic HCV infection, the PAF/pPAF-AH system may be altered and this condition may contribute to HCV-related vascular damage.

Hepatitis C virus core protein enhances B lymphocyte proliferation

HCV chronic infection leads to liver diseases and also to a wide range of extrahepatic disorders including benign, but pre-lymphomatous forms (mixed cryoglobulinemia) to frank hematological neoplasia (non-Hodgkin's lymphoma). Recent data showed the involvement of p53 superfamily members in the pathogenesis of different lymphatic malignancies. In fact, tymomas and a subset of non-Hodgkin's lymphomas (NHLs) express high levels of p63. Thus, we analyzed whether alterations in p53 superfamily gene expression are observable in B lymphocytes isolated from HCV-infected patients with and without lymphoproliferative disorders. We showed, by real-time PCR, a significant induction of DNp63 mRNAs in B lymphocytes obtained from HCV-positive low grade non-Hodgkin's lymphoma patients. Since our current understanding of HCV proteins emphasizes the ability of the HCV core protein to deregulate the expression and activity of p53-related proteins, we established different B lymphocyte cell lines (Wil2-ns, Daudi and Ramos) stably expressing HCV core protein, in order to investigate the possible involvement of the viral protein in the upregulation of DNp63 in B lymphocytes. The analysis of p63 family transcripts showed no transcriptional changes for the p63 TA isoforms, whereas an increase (>5 times) of DNp63 mRNA occurred. In all cell lines, this abnormal expression was associated with a significant increase of cell proliferation that was specifically inhibited by silencing DNp63 mRNA. These findings suggest a pathogenetic role of the HCV core in HCV-related lymphomagenesis, through the induction of DNp63's pro-proliferative effects.

Hepatitis C virus lymphotropism: lessons from a decade of studies

The possibility that HCV infects lymphoid cells has been widely discussed. Evidence in favor of HCV tropism for lymphoid cells derives from a series of data including: (1) the higher sensitivity of testing HCVRNA in PBMC than in serum or plasma samples, with possible detection of HCV RNA-positive PBMC in the absence of HCV viremia; (2) short-term cultures of PBMC which yield a significant increase in the amount of viral RNA on stimulation by mitogens; (3) results of "in situ" methods (i.e. in situ hybridization, immunofluorescence); (4) efficient infection of lymphoid cell lines or PBMC from normal individuals; (5) the persistence of HCV RNA in PBMC obtained from HCV-positive subjects and injected into SCID mice; (6) the long-term persistence of HCV RNA in PBMC in spite of HCV RNA negativity of serum and liver in sustained responder patients after therapy. The principal criticisms concerning effective HCV infection of lymphoid cells arise from technical difficulty in identifying HCV RNA replicative intermediate in these elements. Conflicting data may also result from differences in PBMC infection by different genotypes, samples taken at different stages in the disease process and differences in the sensitivity of detection methods, as well as low replication levels and/or proportion of infected PBMC. Interesting available data about HCV lymphotropism, which is possibly important in influencing the natural history of infection, include: (1) possible preferential viral tropism for specific PBMC subsets; (2) different lymphotropism of different viral strains; (3) selection of distinctive viral strains; (4) identification of putative HCV cell receptors; (5) association between determination of HCV lymphatic infection and t(14; 18) translocation. The clinical correlates of HCV lymphotropism are potentially very numerous, including, first, its role in determining HCV-related lymphoproliferative disorders.

Hepatitis C virus-related lymphoproliferative disorders: An overview

Hepatitis C virus (HCV) is a global health problem affecting 3% of the world's population (about 180 million) and a cause of both hepatic and extrahepatic diseases. B-cell lymphoproliferative disorders, whose prototype is mixed cryoglobulinemia, represent the most closely related as well as the most investigated HCV-related extrahepatic disorder. The association between extrahepatic (lymphoma) as well as hepatic malignancies (hepatocellular carcinoma) has justified the inclusion of HCV among human cancer viruses. HCV-associated manifestations also include porphyria cutanea tarda, lichen planus, nephropathies, thyreopathies, sicca syndrome, idiopathic pulmonary fibrosis, diabetes, chronic polyarthritis, sexual dysfunctions, cardiopathy/atherosclerosis, and psychopathological disorders. A pathogenetic link between HCV virus and some lymphoproliferative disorders was confirmed by their responsiveness to antiviral therapy, which is now considered the first choice treatment. The aim of the present paper is to provide an overview of extrahepatic manifestations of HCV infection with particular attention to B-cell lymphoproliferative disorders. Available pathogenetic hypotheses and suggestions about the most appropriate, currently available, therapeutic approaches will also be discussed.

Cryoglobulinemia related to hepatitis C virus infection

A causal link among hepatitis C virus (HCV) infection and essential mixed cryoglobulinemia, cryoglobulinemic glomerulonephritis, and vasculitis is strongly supported. HCV triggers autoimmune response in predisposed individuals that manifests as organ-specific and non-organ-specific autoantibodies and as polyclonal/monoclonal rheumatoid factor, which has a central role in causing damaging cryoglobulin and immune complex tissue levels. Immunologic events are mainly induced by HCV infection persistence, with excessive immune stimulation. Humoral immune dysfunction leads to autoantibodies and rheumatoid factor production with cryoglobulinemia, glomerulonephritis, vasculitis, neuropathy, and probably thyroiditis, and arthritis in rare cases. Cellular immune dysfunction leads to lymphocytic infiltration, proliferation, and cytokine production. Pegylated (or not) interferon-alpha in combination with ribavirin appears to be the treatment of choice for patients with symptomatic essential mixed cryoglobulinemia with or without glomerulonephritis. Novel treatment with rituximab is promising.

Involvement of PI3K in HCV-related lymphoproliferative disorders

Hepatitis C virus (HCV) core protein has been shown to deregulate cell growth and programmed cell death in hepatoma cells, but only minimal informations are available about its possible role on B-lymphoproliferative disorders (LPDs). The aim of our work was to analyze the biological activity of HCV core protein on B-cell proliferation. We established Wil2-ns and Ramos B-cell lines that stably expressed the HCV core protein. Growth curve, thymidine incorporation analysis, as well as the expression of PCNA and activated-ERKs demonstrated that HCV core protein induced an increased growth in both cell lines. Interestingly, the HCV core protein expression determined, in our model, a downregulation of DNp73 and an upregulation of DNp63, which was essential for the maintenance of viral-dependent effects on cell growth. Finally, we have identified phosphoinositide 3-kinase (PI3K) as mediator of HCV core-dependent transcriptional increase of DNp63, which in turn correlated with the increasing of lymphocyte proliferation. In primary B-lymphocytes, derived from HCV-related low-grade non-Hodgkin's lymphoma patients, consistent results were obtained. These findings provide evidence for a possible pathogenetic role played by HCV core protein in HCV-related lymphomagenesis; it could occur through the deregulation of PI3K activity, consequent activation of Akt and overexpression of DNp63.

Modifications of plasma platelet-activating factor (PAF)-acetylhydrolase/PAF system activity in patients with chronic hepatitis C virus infection

Hepatitis C virus (HCV) chronically infects about 200 million individuals worldwide and leads to severe liver and lymphatic diseases. HCV circulates in the serum, associated with apoB-containing lipoproteins. Platelet-activating factor (PAF), a pro-inflammatory mediator, is mainly modulated by plasma PAF-acetylhydrolase (pPAF-AH), associated with ApoB100-containing low-density lipoproteins (LDL). The aim of the study was to evaluate the potential effects of chronic HCV infection on the PAF/pPAF-AH system. HCV-RNA was detected in plasma, peripheral blood mononuclear cells (PBMC) and liver samples. Plasma PAF levels, pPAF-AH activity, ApoB100 serum titres and pPAF-AH mRNA levels in cultured macrophages were determined. Plasma PAF levels were significantly higher and pPAF-AH activity was significantly lower in HCV patients than in controls. No significant modifications of pPAF-AH mRNA in macrophages or in ApoB100 values were observed in HCV patients compared with controls. Patients who cleared HCV after antiviral treatment showed a complete restoration of pPAF-AH activity and significant decrease of PAF levels during the follow-up. No data exist about the PAF/pPAF-AH system behaviour during HCV infection. This study shows that in HCV patients modifications of pPAF-AH activity/PAF levels take place and that HCV clearance restored pPAF-AH activity. This suggests that circulating viral particles play a role in PAF/pPAF-AH system modifications and such an alteration could be involved in HCV-related damage.

Hepatitis C virus genotypes in southern Taiwan: prevalence and clinical implications

The role of hepatitis C virus (HCV) genotypes in the development of hepatocellular carcinoma (HCC) is still controversial. To determine the distribution and clinical implications of HCV genotypes in southern Taiwan, we analysed 418 patients with chronic HCV infections. HCV genotypes were determined using an HCV Line Probe Assay. The predominant HCV genotype was 1b (45.5%), followed by 2a/2c (30.9%) and 2b (6.9%). The prevalence of genotype 1b in HCC patients (60.3%) was significantly higher than in those with liver cirrhosis (38.7%) and chronic hepatitis (38.7%) (P=0.003 and P<0.001, respectively). Patients with chronic HCV 2a/2c infection had higher alanine aminotransferase (ALT) levels than those with chronic HCV 1b infection (P<0.001). Univariate analysis revealed that disease severity was significantly correlated with older age, genotype 1b, lower ALT levels and lower viral load. Based on multiple logistic regression analysis, after adjusting for age and serum HCV RNA levels, HCV 1b infection was still a significant risk factor for HCC. In conclusion, the predominant genotypes in southern Taiwan were 1b and 2a/2c, and disease severity was associated with genotype 1b.

Hepatitis C virus in elderly cancer patients

BACKGROUND

There are few studies about the relationship between HCV and the development of other tumors. We consider the prevalence of HCV infection in elderly cancer patients who have tumors different from that in hepatocellular carcinoma and non-Hodgkin's lymphoma.

METHODS

We evaluated the prevalence of HCV infection in 236 elderly cancer patients in comparison with 300 elderly volunteers. Cancer patients presented a variety of tumors other than hepatocarcinoma and lymphoma, namely, colorectal (n=66), breast (n=44), bladder (n=40), prostate (n=30), lung (n=22), kidney (n=15), pancreatic (n=6), thyroid (n=5), cervical (n=4), melanoma (n=3) and vaginal (n=1).

RESULTS

Among the 236 elderly cancer patients, 87 were positive for HCV antibodies (36%) and, among the 300 elderly patients, 32 were positive (10%). A comparison between the two groups revealed a statistically significant difference (p<0.001) between patients with kidney cancer, bladder cancer or prostate cancer, and the control group.

CONCLUSIONS

The high anti-HCV prevalence in elderly cancer patients may be due to several mechanisms. These patients are more prone to acquire an HCV infection because of their frequent hospitalizations and the immunological changes in patients with tumors may lower their threshold for HCV infection.

Viral etiology of hepatocellular carcinoma and HCV genotypes in Taiwan

Etiologic variations of hepatocellular carcinoma (HCC) exist in different geographic areas of the world. Hepatitis B virus infection is associated with HCC. However, hepatitis C virus (HCV) infection plays an increasingly more important role in the development of HCC and is associated with more than 30% of HCC in Taiwan. The prevalence of HCV infection and HCV genotypes vary in different geographic areas. The prevalence of HCV genotype 1b (HCV-1b) was around 50-70% in Taiwan and even varied in different townships. In addition to host factors, HCV genotypes may be associated with the development of HCC. In our study, the prevalence of HCV-1b in patients with HCC was significantly higher than in those with liver cirrhosis and chronic hepatitis; multivariate analysis revealed that the disease severity was significantly correlated with age and HCV-1b. Furthermore, HCV-1b was associated with a lower response rate to interferon (IFN) therapy than HCV-2. Our study has demonstrated that mutations in the IFN sensitivity-determining region, spanning nucleotides 2,209-2,248 in the NS5A region, correlate with the sustained virological response to combination therapy with IFN and ribavirin in patients with chronic HCV-1b infection in Taiwan. A third-generation enzyme immunoassay for antibody to HCV can be used to predict viremia and monitor the virological response.

Flow cytometric detection of hepatitis C virus antigens in infected peripheral blood leukocytes: binding and entry

AIM

We designed two synthetic-core-specific peptides core 1 (C1) and core 2 (C2), and an E1-specific peptide (E1). We produced specific polyclonal antibodies against these peptides and used the antibodies for detection of HCV antigens on surface and within infected peripheral blood leukocytes.

METHODS

Peripheral blood from a healthy individual who tested negative for HCV RNA was incubated with HCV type 4 infected serum for 1 h and 24 h at 37 degrees C. Cells were stained by direct and indirect immunofluorescence and measured by flow cytometry.

RESULTS

After 1 h of incubation, antibodies against C1, C2, and E1 detected HCV antigens on the surface of 27%, 26% and 73% of monocytes respectively, while 10%, 5% and 9% of lymphocytes were positive with anti-C1, anti-C2 and anti-E1 respectively. Only 1-3% of granulocytes showed positive staining with anti-C1, anti-C2 and anti E1 antibodies. After 24 h of incubation, we found no surface staining with anti-C1, anti-C2 or anti-E1. Direct immunostaining using anti-C2 could not detect intracellular HCV antigens, after 1 h of incubation with the virus, while after 24 h of incubation, 28% of infected cells showed positive staining. Only plus strand RNA was detectable intracellularly as early as 1 h after incubation, and remained detectable throughout 48 h post-infection. Interestingly, minus RNA strand could not be detected after 1 h, but became strongly detectable intracellularly after 24 h post-infection.

CONCLUSION

Monocytes and lymphocytes are the preferred target cells for HCV infection in peripheral blood leukocytes. Our specific anti-core and anti-E1 antibodies are valuable reagents for demonstration of HCV cell cycle. Also, HCV is capable of infecting and replicating in peripheral blood mononuclear cells as confirmed by detection of minus strand HCV RNA as well as intracellular staining of core HCV antigen.

Flow cytometric detection of hepatitis C virus antigens in infected peripheral blood leukocytes: binding and entry

AIM

We designed two synthetic-core-specific peptides core 1 (C1) and core 2 (C2), and an E1-specific peptide (E1). We produced specific polyclonal antibodies against these peptides and used the antibodies for detection of HCV antigens on surface and within infected peripheral blood leukocytes.

METHODS

Peripheral blood from a healthy individual who tested negative for HCV RNA was incubated with HCV type 4 infected serum for 1 h and 24 h at 37 degrees C. Cells were stained by direct and indirect immunofluorescence and measured by flow cytometry.

RESULTS

After 1 h of incubation, antibodies against C1, C2, and E1 detected HCV antigens on the surface of 27%, 26% and 73% of monocytes respectively, while 10%, 5% and 9% of lymphocytes were positive with anti-C1, anti-C2 and anti-E1 respectively. Only 1-3% of granulocytes showed positive staining with anti-C1, anti-C2 and anti E1 antibodies. After 24 h of incubation, we found no surface staining with anti-C1, anti-C2 or anti-E1. Direct immunostaining using anti-C2 could not detect intracellular HCV antigens, after 1 h of incubation with the virus, while after 24 h of incubation, 28% of infected cells showed positive staining. Only plus strand RNA was detectable intracellularly as early as 1 h after incubation, and remained detectable throughout 48 h post-infection. Interestingly, minus RNA strand could not be detected after 1 h, but became strongly detectable intracellularly after 24 h post-infection.

CONCLUSION

Monocytes and lymphocytes are the preferred target cells for HCV infection in peripheral blood leukocytes. Our specific anti-core and anti-E1 antibodies are valuable reagents for demonstration of HCV cell cycle. Also, HCV is capable of infecting and replicating in peripheral blood mononuclear cells as confirmed by detection of minus strand HCV RNA as well as intracellular staining of core HCV antigen.

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.

HCV core protein localizes in the nuclei of nonparenchymal liver cells from chronically HCV-infected patients

Understanding the mechanism of hepatitis C virus (HCV) pathogenesis is an important part of HCV research. Recent experimental evidence suggests that the HCV core protein (HCcAg) has numerous functional activities. These properties suggest that HCcAg, in concert with cellular factors, may contribute to pathogenesis during persistent HCV infection. HCV is capable of infecting cells other than hepatocytes. Although the extrahepatic cellular tropism of HCV may play a role in the pathophysiology of this infection, the precise biological significance of the presence of HCV components in different liver cell types presently remains to be established. In this study, HCcAg was detected in nonparenchymal liver cells of six patients out of eight positive for serum HCV RNA. Immunostaining with anti-HCcAg mAbs revealed the presence of this protein in different liver cell types such as lymphocytes, Kupffer, polymorphonuclear, pit, endothelial, stellate, and fibroblast-like cells. Interestingly, HCcAg was immunolabeled not only in the cytoplasm but also in the nucleus of these cells. Remarkably, HCcAg co-localized with large lipid droplets present in stellate cells and with collagen fibers in the extracellular matrix. Moreover, HCcAg was immunolabeled in bile canaliculus suggesting the involvement of the biliary system in the pathobiology of HCV. Data suggest that nonparenchymal liver cells may constitute a reservoir for HCV replication. Besides, HCcAg may contribute to modulate immune function and fibrosis in the liver as well as steatosis.

Identification of unique hepatitis C virus quasispecies in the central nervous system and comparative analysis of internal translational efficiency of brain, liver, and serum variants

Reports of cerebral dysfunction in chronic hepatitis C virus (HCV) infection have led to the suggestion that HCV may infect the central nervous system (CNS). We used reverse transcription-PCR, cloning, and sequencing to define quasispecies for the HCV internal ribosomal entry site (IRES) and hypervariable region 1 (HVR1) in autopsy-derived brain, liver, lymph node, and serum samples. There was evidence of tissue compartmentalization of sequences in the brain in two patients, with between 24 and 55% of brain-derived IRES sequences absent from the serum, and significant phylogenetic and phenetic clustering of the brain and lymph node HVR1 sequences. The IRES initiates cap-independent translation of the viral polyprotein. Two unique brain-derived IRES mutations (C(204)-->A and G(243)-->A), which have previously been associated with lymphoid replication and altered translational efficiency in cell culture, were found in one patient. We used a dicistronic reporter vector to test whether brain-derived variants showed altered IRES-mediated translational efficiency, which might favor CNS infection. The translational efficiencies of the brain-derived IRES sequences were generally reduced compared to those of the master serum and liver sequences in rabbit reticulocyte cell lysates and two human cell lines, HuH7 (liver) and CHME3 (microglial). The C(204)-->A and G(243)-->A mutations showed preserved translational efficiency in HuH7 cells but reduced efficiency in CHME3 cells. Our data provide evidence that the CNS is a site of HCV replication, consistent with the recent demonstration of negative-strand HCV RNA in brain, and suggest that IRES polymorphisms may be important as a viral strategy of reduced translation to favor latency in the CNS.

[Autoantibodies characteristic for autoimmune hepatitis found in chronic hepatitis C]

In the patients with chronic hepatitis C (HHC) there have been found different autoantibodies, some typical for autoimmune hepatitis (AIH) type 1, like: antinuclear antibodies (ANA) in 15-60%, anti-smooth muscle antibodies (ASMA) in 34-60%, or AIH type 2: anti liver/kidney microsomes 1 autoantibodies (LKM 1) in 0-6%. Also, antimitochondrial autoantibodies (AMA), which defines PBC, is discovered in 0.7-1.5% patients with HHC. The purpose of the research was to determine the titr of the serum autoantibodies, which characterise AIH in the patients with HHC and to compare demographical, clinical, biochemical, histological and immunological parameters in the groups of patients: with or without autoantibodies. In 50 patients with HHC are defined clinical (demographical, troubles) facts, laboratorical (the values of complete bilirubin, ALT), histological diagnosis of the liver tissue (PH), and virusological diagnosis (antibodies and antigens of the hepatitis C virus), immunological (autoantibodies, immunoglobulins). The analysis of the results show us that ANA and AMA haven't been present in the patients with HHC in considerable titr (> 1:80), while in 10% of the patients there have been titr of ASMA. In 2 patients were both titrs, ANA (1:40) and ASMA (1:40), as well, which considered important, so there is entirely 7 patients (14%) with detected ANA and ASMA in considerable titr. Autoantibodies, which are characteristic for AIH 2, have not been found in the patients with HHC. Considered the sex, between the group of patients with HHC and autoantibodies, and the group of patients with HHC without autoantibodies, there is no important difference, although the percent of male is a little bit bigger in the second group. Considering the growth, there were no important difference between the patients groups. The fact that appearance of autoantibodies has no correlation with the growth, we can explain with the fact that she most of patients with HHC are persons from 21 to 30 years old, and that the older are no so present. The troubles are present in about the half patients with HHC, and it isn't proved that the appearance of autoantibodies have the influence on this particular clinical parameter. The comparison of activities of the disease, the analysis of the ALT values and the bilirubin, we also didn't get considerable difference between these two groups of patients. Three patients who haven't autoantibodies, but they have the ALT values expended between 5 and 10 times, which we consider the high grade of the necrosis. This high values we can't notice in the patients with autoantibodies. The parameters of grade inflammatory reactions of the extent values of Ig, so as IgG category, also doesn't show we the important difference between the groups. The most patients have normal values both: Ig and IgG. Despite that in both categories of the patients, there is no considerable difference in PH, as well as, in the stage of fibrosis, two patients without autoantibodies have more visible degree of necrosis, manifested like reasonable necrosis, while all the others patients have gently visible necrosis. It is important to say that the patients with autoantibodies have no histological indications for AIH, in the PH sense, and the presence of more important plasmatic infiltrate. All the patients with HHC and autoantibodies have higher values CIC, but the frequency of appearance is not different between the both groups, which show us the variety of becaming autoimmune and immune phenomena in HHC. Based on produced results, we can conclude that: 1. autoantibodies which are characteristic for AIH 1 are visible in 14% of the HHC patients, 2. there are more ASMA in HHC, then ANA; 3. there is no autoantibodies, which caracterize AIH 2, in HHC; 4. the growth and the sex of the patients with HHC have no influence on showing autoantibodies characteristic for AIH; 5. the presence of autoantibodies, characteristic for AIH 1, have no importance of showing the burdens in the patients, degree of PH and the stadium of the diseases, and also on the value of Ig and IgG; 6. discovering the autoantibodies in HHC, no matter there Is no considerable presence on it's symptomatology and the prognosis, oblige us on further following and analysis for starting antivirus therapy, In order to present eventual beginning of AIH.

Hepatitis C virus induces a mutator phenotype: enhanced mutations of immunoglobulin and protooncogenes

Hepatitis C virus (HCV) is a nonretroviral oncogenic RNA virus, which is frequently associated with hepatocellular carcinoma (HCC) and B cell lymphoma. We demonstrated here that acute and chronic HCV infection caused a 5- to 10-fold increase in mutation frequency in Ig heavy chain, BCL-6, p53, and beta-catenin genes of in vitro HCV-infected B cell lines and HCV-associated peripheral blood mononuclear cells, lymphomas, and HCCs. The nucleotide-substitution pattern of p53 and beta-catenin was different from that of Ig heavy chain in HCV-infected cells, suggesting two different mechanisms of mutation. In addition, the mutated protooncogenes were amplified in HCV-associated lymphomas and HCCs, but not in lymphomas of nonviral origin or HBV-associated HCC. HCV induced error-prone DNA polymerase zeta, polymerase iota, and activation-induced cytidine deaminase, which together, contributed to the enhancement of mutation frequency, as demonstrated by the RNA interference experiments. These results indicate that HCV induces a mutator phenotype and may transform cells by a hit-and-run mechanism. This finding provides a mechanism of oncogenesis for an RNA virus.

Pathophysiology of Hepatitis C and HIV Coinfection

Hepatitis C infection is the most common cause of chronic hepatitis that can lead to cirrhosis and hepatocellular cancer. Hepatitis C virus infects approximately 70 million people worldwide. Hepatitis C is usually transmitted by injection drug use and blood transfusion. Hepatitis C is prevalent in HIV-infected individuals. Coinfection complicates the treatment of these two distinct viral infections. Understanding the normal functions of the liver and the pathophysiological effects of coinfection enables health care professionals to provide the highest level of care for these individuals.

Effect of antiviral treatment in patients with chronic HCV infection and t(14;18) translocation

Hepatitis C virus (HCV) may be associated with the mixed cryoglobulinemia syndrome and other B-cell lymphoproliferative disorders (LPDs). The t(14;18) translocation may play a pathogenetic role. Limited data are available regarding the effects of antiviral therapy on rearranged B-cell clones. We evaluated the effects of interferon and ribavirin on serum, B-lymphocyte HCV RNA, and t(14; 18) in 30 HCV+, t(14;18)+ patients without either mixed cryoglobulinemia syndrome or other LPDs. The t(14;18) translocation was analyzed by both bcl-2/JH polymerase chain reaction and bcl-2/JH junction sequencing in peripheral blood mononuclear cells in all patients. Fifteen untreated patients with comparable characteristics served as controls. Throughout the study, the presence or absence of both t(14;18) and HCV RNA sequences were, in most cases, associated in the same cell samples. At the end of treatment, t(14;18) was no longer detected in 15 patients (50%) with complete or partial virologic response, whereas it was persistently detected in nonresponders (P <.05), as well as in 14 of 15 control patients. In 4 responder patients, t(14;18) and HCV RNA sequences were no longer detected in blood cells after treatment, but were again detected after viral relapse; the same B-cell clones were involved in the pretreatment and posttreatment periods. In conclusion, this study suggests that antiviral therapy may induce regression of t(14;18)-bearing B-cell clones in HCV+ patients and that this phenomenon may be related, at least in part, to the antiviral effect of therapy. This in turn suggests that antiviral treatment may help prevent or treat HCV-related LPDs.

HCV replication in PBMC and its influence on interferon therapy

AIM: To study hepatic virus C (HCV) RNA and HCV protein expression in peripheral blood mononuclear cells (PBMCs) of patients with HCV infection, and explore the relationship between the HCV RNA in the PBMCs and response to interferon (IFN) therapy.

METHODS: Type-specific primers were designed and RT-nested PCR was used to detect the plus- and minus- strands of HCV RNA in PBMCs of 54 patients with HCV infection; Indirect immunofluorescence assay was applied to identify HCVNS5 protein expression in PBMCs; 6 month-, 3 MU-IFN regiment was administrated to observe the responses to IFN in 35 chronic hepatitis C patients with different HCV RNA status in PBMCs.

RESULTS: HCV plus strand RNA was found in 10 of 19 (52.6%) acute hepatitis C patients and 22 of 35 (62.9%) chronic hepatitis C patients. HCV minus strand RNA was detected in 14 of 35 (40.0%) chronic hepatitis C patients, but only one patient (5.3%) with acute HCV infection was found to be minus HCV RNA positive. Though no HCV NS5 protein expression was found in the examined 10 cases of acute HCV infection, it was positive in 17 of 20 (85.0%) chronic hepatitis C patients by indirect immunofluoresence assay. There are significant differences of positive rate of the minus-strand and HCVNS5 protein between acute and chronic hepatitis C groups (u = 2.07, P < 0.05 and u = 4.43, P < 0.01 respectively). The patients with minus-strand HCV RNA showed a significantly lower 6-month sustained response (SR-6) to IFN compared to those without minus-strand HCVRNA in PBMCs (biologically 14.3% vs 42.8%, χ² = 4.12, P < 0.05 and virologically 7.1% vs 23.9%, χ² = 4.24, P < 0.05).

CONCLUSION: HCV is capable of infecting and replicating in PBMCs, and HCVNS5 protein was expressed in PBMCs. The patients with minus strand HCV RNA in PBMCs showed a significantly lower 6-month sustained response to IFN, suggesting that minus-strand HCV RNA in PBMCs may be one of the factors influencing response to IFN therapy.

Role of the asialoglycoprotein receptor in binding and entry of hepatitis C virus structural proteins in cultured human hepatocytes

We used a baculovirus-based system to prepare structural proteins of hepatitis C virus (HCV) genotype 1a. Binding of this preparation to cultured human hepatic cells was both dose dependent and saturable. This binding was decreased by calcium depletion and was partially prevented by ligands of the asialoglycoprotein receptor (ASGP-R), thyroglobulin, asialothyroglobulin, and antibody against a peptide in the carbohydrate recognition domain of ASGP-R but not preimmune antibody. Uptake by hepatocytes was observed with both radiolabeled and dye-labeled HCV structural proteins. With hepatocytes expressing the hH1 subunit of the ASGP-R fused to green fluorescent protein, we could show by confocal microscopy that dye stain cointernalized with the fusion protein in an area surrounding the nucleus. Internalization was more efficient with a preparation containing p7 than with one that did not. The two preparations bound to transfected 3T3-L1 cells expressing either both (hH1 and hH2) subunits of the ASGP-R (3T3-22Z cells) or both hH1 and a functionally defective variant of hH2 (3T3-24X cells) but not to parental cells. Additionally, uptake of dye-labeled preparation containing p7 was observed with 3T3-22Z cells but not with 3T3-L1 or 3T3-24X cells or with the preparation lacking p7, suggesting that p7 regulates the internalization properties of HCV structural proteins. Our observations suggest that HCV structural proteins bind to and cointernalize with the ASGP-R in cultured human hepatocytes.

Association between hepatitis C infection and other infectious diseases: a case for targeted screening?

OBJECTIVE

Hepatitis C virus (HCV) shares risk factors and routes of transmission with several other infectious agents. However, the prevalence of comorbid infectious disorders among HCV-infected patients remains unknown. To analyze the association between HCV and several categories of infectious disorders, we carried out a case-control study using information from 172 hospitals contained in the computerized databases of the Department of Veterans Affairs.

METHODS

We identified all HCV-infected patients who were hospitalized during 1992-1999. For each case, four control subjects without HCV were randomly chosen from hospitalized patients and were matched with cases on the year of admission. The frequencies of several predefined infectious disease diagnoses were compared between cases and control subjects, and the strength of these associations were assessed in multivariable logistic regression analyses.

RESULTS

We identified 34,204 HCV-infected patients (cases) and 136,816 control subjects without HCV. Patients in the case group were younger (48.4 yr vs 59.8 yr), were more frequently nonwhite (38.5% vs 26.5%), and were more likely to have served in Vietnam (68.1% vs 33.0%); all p < 0.0001. Compared with control subjects, patients with HCV had a significantly higher prevalence of other blood-borne virus infections, including HIV (14.1% vs 3.0%) and hepatitis B (22.4% vs 0.7%); immunodeficiency-related infections, including cytomegalovirus (0.6% vs 0.2%), toxoplasmosis (0.3% vs 0.1%), cryptococcosis (0.4% vs 0.1%), and tuberculosis (3.3% vs 1.3%); sexually transmitted diseases, including gonococcus (0.5% vs 0.1%), chlamydia (1.6% vs 0.7%), syphilis (2.0% vs 0.6%), and genital herpes (1.0% vs 0.3%); and bacterial infection, including peritonitis, sepsis, endocarditis, cellulitis, and carbuncles (all p < 0.0001). After excluding potentially immunocompromised patients, including those with HIV, organ transplant, and cirrhosis, HCV remained significantly associated with CMV, cryptococcus, tuberculosis, and sexually transmitted diseases. Similar results were obtained when the analyses were restricted to Vietnam-era veterans.

CONCLUSIONS

Several infectious diseases are more common among HCV-infected patients compared with those without HCV infection. These findings support an approach of targeted screening for HCV among patients with these infectious diseases.

Mechanisms of drug resistance and novel approaches to therapy for chronic hepatitis C

Hepatitis C virus (HCV) is now the major cause of transfusion-associated and parenterally transmitted viral hepatitis and accounts for a significant proportion of hepatitis cases worldwide. The majority of infections become persistent and approximately 20% of chronically infected individuals develop cirrhosis, which is strongly associated with progression to hepatocellular carcinoma. Molecular biological investigations into the structure and function of HCV and its genes has led to the identification of a number of potential targets for selective antiviral intervention. The present review summarizes current research activity into these novel drug targets and addresses the basis for clinical non-response in the current interferon-alpha-based therapies. Future therapeutic strategies that utilize HCV-specific antiviral agents should prove effective in controlling active viral replication, but the risk of emergence of drug-resistance will need to be addressed due to the quasispecies feature of HCV replication.

Hepatitis C and B-cell lymphoma: the hemato-hepatologist linkage

Hepatitis C virus (HCV)-lymphotropism may be responsible for the development of mixed cryoglobulinemia (MC) and other lymphoproliferative disorders associated with HCV infection. An association between HCV infection and B-cell lymphoma has been largely demonstrated in several geographical areas with prevalence ranging between 7.4 and 37%. However, the intimate pathogenetic mechanism involved in HCV-associated lymphomas remains considerably unknown. HCV may exerts its oncogenic potential via an indirect mechanism or utilizes other pathways directly. It is reasonable to assume that several different pathogenetic mechanisms operate in the wide spectrum of HCV-related lymphomas which includes the 'idiopathic', non-cryoglobulinemic, intermediate to high-grade lymphoma, and the more common indolent, low-grade lymphoma, preceded by long standing symptomatic MC type II. In most cases, HCV has no significant impact on response to chemotherapy or survival of lymphoma patients. Treatment with chemotherapy is relatively safe, and interruption of treatment regimens is usually not required. Whether to treat low-grade HCV-related lymphomas with anti-viral therapy is still debatable, but encouraging data emerge from recent studies.

Impaired lung epithelial permeability in hepatitis C virus antibody positive patients detected by 99mTc-DTPA aerosol scintigraphy

Chronic hepatitis C virus (HCV) infection has been recently identified as an aetiological agent in idiopathic pulmonary fibrosis. The present study was designed to determine the pulmonary clearance rate of 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) in asymptomatic HCV antibody positive (HCV Ab+) patients and the role of 99mTc-DTPA aerosol scintigraphy in the early detection of lung involvement. Twenty-six non-smoker HCV Ab+ and HCV-RNA (+) patients (20 female, six male; aged 43+/-11 years), with no clinical pulmonary symptoms, and normal radiological findings, were studied. Thirty-one healthy non-smoker volunteers (24 female, seven male; aged 40+/-10 years) were taken as a control group. 99mTc-DTPA aerosol inhalation scintigraphy and pulmonary function tests were performed in all patients and in controls. On the basis of the scintigrams the percentage decline in activity per minute (Kep) was evaluated, which represented an accurate parameter of lung membrane permeability. The mean Kep values of healthy controls (0.78+/-0.13 for left lung, 0.79+/-0.14 for right lung) were significantly lower than HCV Ab+ patients (1.10+/-0.31 for left lung, 1.11+/-0.34 for right lung, P<0.001). But no significant change was observed in PFT (P>0.05). We conclude that subclinical alveolitis and/or interstitial lung disease may be present in patients with HCV Ab+, since it is known that an increase in the epithelial permeability of the lung is an early manifestation of interstitial disease.

Immunopathogenesis of hepatitis C virus infection

Hepatitis C virus, a recently identified member of the family Flaviviridae, is an important cause of chronic viral hepatitis and cirrhosis. There are similarities in the nature of the immune response to this pathogen with immunity in other flavivirus and hepatotropic virus infections, such as hepatitis B. However, the high rate of viral persistence after primary hepatitis C infection, and the observation that neutralizing antibodies are not protective, would suggest that there are a number of important differences between hepatitis C, other flaviviruses, and hepatitis B. The phenomenon of quasispecies evolution and other viral factors have been proposed to contribute to immune evasion by hepatitis C virus. In the face of established persistent infection, virus-specific cytotoxic T lymphocytes may exert some control over viral replication. However, these same effectors may also be responsible for the progressive liver damage characteristic of chronic hepatitis C infection. The nature of protective immunity, including the role of innate immune responses early after hepatitis C exposure, remains to be defined.

Mixed cryoglobulinemia: new concepts

The most documented extrahepatic manifestation of hepatitis C virus (HCV) infection is mixed cryoglobulinemia (MC). MC is characterised by the presence of temperature-sensitive protein complexes: in type II MC, cryoglobulins are composed of a monoclonal rheumatoid factor (usually, IgMkappa) against polyclonal IgG. In type III MC, all components are polyclonal. The presence of microheterogeneity and other new types of cryoglobulins is a novel and recent observation. The production of different autoantibodies and circulating immune complexes, including the cryoglobulins, are responsible for systemic vasculitis and various organ damage. In a limited number of MC patients, a malignancy, that is B-cell non-Hodgkin's lymphoma or hepatocellular carcinoma, may also develop. Finally, results of interferon and/or ribavirin treatments in MC patients represent an indirect proof for the pathogenetic link between MC and HVC infection. The discovery of the relation between HCV infection and MC shows the striking association between a viral infection and an autoimmune disease and, thus, a potential link between the systemic autoimmune and lymphoproliferative disorders.

Auto-antibodies in hepatitis C

Hepatitis C virus (HCV) has been implicated in the development of a variety of autoimmune phenomena, some of which are well documented and include a panel of auto-antibodies shared with autoimmune hepatitis (AIH). Anti-nuclear (ANA) and smooth muscle (SMA) antibodies (markers of AIH type 1 [AIH-1]), have been demonstrated in 9-38% and 5-91% of cases respectively, whereas anti-liver/kidney microsomal type 1 (anti-LKM-1) and anti-liver cytosol type 1 antibodies (anti-LC1) (markers of AIH type 2 [AIH-2]), are definitely rarer, especially in adults. The presence of these auto-reactivities in chronic hepatitis C generates clinical overlaps and dilemmas in the correct classification and treatment of such patients. The immunopathological characterization of the auto-antibodies, anti-nuclear and smooth muscle antibodies in particular, combined with internationally defined criteria for the diagnosis of AIH is helpful in this clinical process. Thyroid auto-antibodies and cryoprecitable rheumatoid factors are also commonly detected in hepatitis C, while the occurrence of other auto-antibodies still awaits confirmation.

In Vivo Tropism of Hepatitis C Virus Genomic Sequences in Hematopoietic Cells: Influence of Viral Load, Viral Genotype, and Cell Phenotype

Extrahepatic sites capable of supporting hepatitis C virus (HCV) replication have been suggested. We analyzed the influence of virological factors such as viral genotype and viral load, and cellular factors such as cell phenotype, on the detection rate of HCV sequences in hematopoietic cells of infected patients. Thirty-eight chronically infected patients were included in the study: 19 infected by genotype 1 isolates (1a and 1b), 13 by nongenotype 1 isolates (including genotypes 2 a/c, 3a, and 4), and 6 coinfected by genotype 1 and 6 isolates. Polymerase chain reaction (PCR) detection efficiency of viral genomic sequences, both the positive and negative strand RNA, was evaluated using RNA transcripts derived from genotype 1, 2, 3, and 4 cloned sequences and found to be equivalent within one log unit. The serum viral load, ranging from less than 2 × 105 Eq/mL to 161 × 105 Eq/mL, did not influence the detection rate of either strand of RNA in patients' peripheral blood mononuclear cells (PBMCs). Positive and negative strand RNA were found in PBMCs of all 3 cohorts of patients with a detection rate ranging from 15% to 100% and from 8% to 83.3% for the positive and negative strand RNA, respectively. Coinfected patients showed a detection rate in all cases greater than 80%. Patients infected with genotype 1 isolates showed a higher detection rate of either strands of RNA when compared with patients infected with other genotypes (P < .001 andP < .04). Both strands were found restricted to polymorphonuclear leukocytes, monocytes/macrophages, and B (but not T) lymphocytes. These data show that HCV genomic sequences, possibly reflecting viral replication, can be detected in PBMCs of chronically infected patients independent of the viral load and that specific associated cell subsets are implicated in the harboring of such sequences.

In Vivo Tropism of Hepatitis C Virus Genomic Sequences in Hematopoietic Cells: Influence of Viral Load, Viral Genotype, and Cell Phenotype

Extrahepatic sites capable of supporting hepatitis C virus (HCV) replication have been suggested. We analyzed the influence of virological factors such as viral genotype and viral load, and cellular factors such as cell phenotype, on the detection rate of HCV sequences in hematopoietic cells of infected patients. Thirty-eight chronically infected patients were included in the study: 19 infected by genotype 1 isolates (1a and 1b), 13 by nongenotype 1 isolates (including genotypes 2 a/c, 3a, and 4), and 6 coinfected by genotype 1 and 6 isolates. Polymerase chain reaction (PCR) detection efficiency of viral genomic sequences, both the positive and negative strand RNA, was evaluated using RNA transcripts derived from genotype 1, 2, 3, and 4 cloned sequences and found to be equivalent within one log unit. The serum viral load, ranging from less than 2 × 105 Eq/mL to 161 × 105 Eq/mL, did not influence the detection rate of either strand of RNA in patients' peripheral blood mononuclear cells (PBMCs). Positive and negative strand RNA were found in PBMCs of all 3 cohorts of patients with a detection rate ranging from 15% to 100% and from 8% to 83.3% for the positive and negative strand RNA, respectively. Coinfected patients showed a detection rate in all cases greater than 80%. Patients infected with genotype 1 isolates showed a higher detection rate of either strands of RNA when compared with patients infected with other genotypes (P < .001 andP < .04). Both strands were found restricted to polymorphonuclear leukocytes, monocytes/macrophages, and B (but not T) lymphocytes. These data show that HCV genomic sequences, possibly reflecting viral replication, can be detected in PBMCs of chronically infected patients independent of the viral load and that specific associated cell subsets are implicated in the harboring of such sequences.

Clonality of B-cells in portal lymphoid infiltrates of HCV-infected livers

Evidence has been accumulating in favour of a role for hepatitis C virus (HCV) in the pathogenesis of human lymphoproliferative disorders. HCV infection has been documented in the majority of patients with essential mixed cryoglobulinaemia type II (MC-II); in patients with HCV infection, B-cell clonal expansion have been detected in peripheral blood and bone marrow, and a high prevalence of B-cell non-Hodgkin's lymphomas has been documented. Liver biopsies in chronic hepatitis C frequently show portal lymphoid infiltrates with features of B follicles, whose clonality has not yet been investigated. This study has analysed the B-cell clonality of portal lymphoid infiltrates from 16 patients with chronic HCV hepatitis. Portal tracts showing obvious lymphoid infiltrates were microdissected from the paraffin-embedded liver tissue sections and the clonality of lymphoid B-cells was tested using a polymerase chain reaction (PCR) approach designed to identify immunoglobulin heavy chain gene (IgH) rearrangements. A successful IgH-PCR analysis was achieved in 35 lymphoid infiltrates from 11 patients (seven with the four without MC-II) and yielded a single band in 21 cases, two bands in ten cases, and three bands in four cases. Comparison of the IgH-PCR amplification bands obtained from the different lymphoid aggregates of the same biopsy revealed that they differed in size. This finding indicates that each aggregate derives from the proliferation of one or a few founder B-cells, which are not related to each other. The results obtained in patients with and without MC-II were similar, suggesting that the presence of B-cell clonal proliferations in liver biopsies is independent of the occurrence of B-cells producing monoclonal IgMk cryoglobulins.

The role of immune responses in the pathogenesis of hepatitis C virus infection

Hepatitis C virus (HCV) is notable for the high rate of chronic infection, which occurs in nearly all individuals who become infected. Liver biopsies from individuals with chronic HCV infection are notable for the presence of numerous mononuclear cells, at least some of which are CD4+ and CD8+ T lymphocytes. The immune response to HCV is polyclonal and multispecific, both in terms of antibody and cellular immune responses. Individuals who recover from acute HCV infection appear to have quantitatively more vigorous CD4+ proliferative responses against one or more HCV proteins compared with those individuals who develop chronic disease. CD8+ responses are less well characterized, in part because of the technical difficulties involved in isolating and characterizing these cells. HCV-specific CTL can be readily isolated from the liver and PBMC of chronically infected individuals, and recognize multiple epitopes. Even individuals with the same HLA type do not consistently recognize the same epitope. Thus, there does not appear to be an immunodominant response on the CD8+ level in this infection. CD8+ cells do appear to play some role in limiting viral replication. These responses are insufficient to eradicate virus completely, however, and may cause liver injury once chronic infection is established. Cytokines produced by both CD4+ and CD8+ cells may play an important role in both inhibiting viral replication and causing liver injury. A better understanding of the role of cellular immunity in the pathogenesis of HCV infection may aid in the development of vaccines and immunotherapeutic intervention strategies.