Hepatocellular codistribution of c100, c33, c22, and NS5 hepatitis C virus antigens detected by using immunopurified polyclonal spontaneous human antibodies

HCV NS3Ag: a reliable and clinically useful predictor of antiviral outcomes in genotype 1b hepatitis C virus-infected patients

Since hepatitis C virus (HCV) non-structural 3 (NS3) protease inhibitor (PI) combined with pegylated interferon/ribavirin (PR) has been approved for chronic HCV genotype (GT) 1b infection, a reliable and clinically useful predictor combining with serum HCV RNA to predict early virologic response, breakthrough, and relapse is important during HCV antiviral treatment. We evaluated the role of HCV NS3 antigen (HCV NS3Ag) on the prediction of virologic response in patients with HCV GT1b during PR or PR/simeprevir (triple) therapy. Three hundred patients were recruited, and HCV RNA and HCV NS3Ag were tested at baseline and weeks 2, 4, 12, 24, 48, and 72. NS3Ag and HCV RNA were significantly related (r(2) = 0.67) in the whole patient selection. The kinetic pattern of HCV RNA and HCV NS3Ag during triple treatment was similar. HCV NS3Ag levels in the triple group closely followed those of HCV RNA; the r(2) values were 0.756 (baseline), 0.837 (2 weeks), 0.989 (4 weeks), and 0.993 (12 weeks), respectively. For patients treated with PR, the positive and negative predictive values (PPVs and NPVs) for viral response were 96.31 % and 67.19 %, respectively, at week 4 by using the decrease of NS3Ag (dHCV NS3Ag) combined with HCV RNA. At week 12, the PPV was similar at 94.16 %, while the NPV reached 87.26 %. The PPV and NPV for the prediction of relapse and breakthrough were 90.6 % and 76.7 %, respectively. HCV NS3Ag is a valuable marker and could be a supplementary predictor of HCV RNA for the prediction of antiviral response, breakthrough, or relapse during HCV antiviral treatment.

Epidermal Growth Factor Receptor-Dependent Mutual Amplification between Netrin-1 and the Hepatitis C Virus

Hepatitis C virus (HCV) is an oncogenic virus associated with the onset of hepatocellular carcinoma (HCC). The present study investigated the possible link between HCV infection and Netrin-1, a ligand for dependence receptors that sustains tumorigenesis, in particular in inflammation-associated tumors. We show that Netrin-1 expression is significantly elevated in HCV+ liver biopsies compared to hepatitis B virus (HBV+) and uninfected samples. Furthermore, Netrin-1 was upregulated in all histological stages of HCV+ hepatic lesions, from minimal liver fibrosis to cirrhosis and HCC, compared to histologically matched HCV- tissues. Both cirrhosis and HCV contributed to the induction of Netrin-1 expression, whereas anti-HCV treatment resulted in a reduction of Netrin-1 expression. In vitro, HCV increased the level and translation of Netrin-1 in a NS5A-La-related protein 1 (LARP1)-dependent fashion. Knockdown and forced expression experiments identified the receptor uncoordinated receptor-5 (UNC5A) as an antagonist of the Netrin-1 signal, though it did not affect the death of HCV-infected cells. Netrin-1 enhanced infectivity of HCV particles and promoted viral entry by increasing the activation and decreasing the recycling of the epidermal growth factor receptor (EGFR), a protein that is dysregulated in HCC. Netrin-1 and HCV are, therefore, reciprocal inducers in vitro and in patients, as seen from the increase in viral morphogenesis and viral entry, both phenomena converging toward an increase in the level of infectivity of HCV virions. This functional association involving a cancer-related virus and Netrin-1 argues for evaluating the implication of UNC5 receptor ligands in other oncogenic microbial species.

Long-term leukocyte natural α-interferon and ribavirin treatment in hepatitis C virus recurrence after liver transplantation

AIM: To evaluate the effect of long-term treatment with leukocyte natural α-interferon (ln-α-IFN) plus ribavirin (RBV).

METHODS: Forty-six patients with hepatitis C virus (HCV) recurrence received 3 MU three times a week of ln-α-IFN plus RBV for 1 mo; then, patients with good tolerability (n = 30) were switched to daily IFN administration, while the remaining were treated with the same schedule. Patients have been treated for 12 mo after viral clearance while non-responders (NR) entered in the long-term treatment group. Liver biopsies were planned at baseline, 1 year after sustained virological response (SVR) and at 36 mo after start of therapy in NR. MedCalc software package was used for statistical analysis.

RESULTS: About 16.7% of genotype 1-4 and 70% of genotype 2-3 patients achieved SVR. Nine patients withdrew therapy because of non-tolerance or non-compliance. A significant improvement in serum biochemistry and histological activity was observed in all SVR patients and long-term treated; 100% of patients with SVR achieved a histological response (fibrosis stabilization or improvement) with a significant reduction in mean staging value (from 2.1 to 1.0; P = 0.0031); histological response was observed in 84% of long-term treated patients compared to 57% of drop-out. Six patients died during the entire study period (follow-up 40.6 ± 7.7 mo); of them, 5 presented with severe HCV recurrence on enrollment. Diabetes (OR = 0.38, 95%CI: 0.08-0.59, P = 0.01), leukopenia (OR = 0.54, 95%CI: 0.03-0.57, P = 0.03) and severe HCV recurrence (OR = 0.51, 95%CI: 0.25-0.69, P = 0.0003) were variables associated to survival. Long-term treatment was well tolerated; no patients developed rejection or autoimmune disease.

CONCLUSION: Long-term treatment improves histology in SVR patients and slows disease progression also in NR, leading to a reduction in liver decompensation, graft failure and liver-related death.

Real-time quantitative assay for routine testing of HCV RNA in formalin-fixed, paraffin-embedded liver samples

The assessment of hepatitis C virus (HCV) RNA in liver tissues is clinically relevant in cases where histology, liver function tests, and HCV serology are not sufficient for a definitive diagnosis of HCV-related hepatitis. We analyzed 215 formalin-fixed, paraffin-embedded liver needle biopsies from patients infected with HCV genotypes 1b and 2. HCV RNA extracted from paraffin sections were quantified by means of a TaqMan real-time reverse transcription-polymerase chain reaction method. The quantification of HCV RNA in liver tissue was correlated with the amount of HCV detected by immunohistochemistry (IHC) on paired frozen biopsies, the HCV RNA load in the serum, and the main serum tests of liver function and cholestasis. HCV RNA was detected by real-time reverse transcription-polymerase chain reaction in 169 liver biopsies (78.6%) with a mean value of 13.59+/-37.25 IU/ng. Tissue HCV RNA levels strongly correlated with the IHC results (P<0.001, Spearman test), HCV serum load (P<0.001), aspartate aminotransferase (P=0.001), gamma-glutamyl transpeptidase (P=0.012), and aspartate aminotransferase/alanine aminotransferase ratio (P=0.029). HCV RNA was amplified in up to 7-year-old archival tissue samples. Real-time HCV RNA quantification on archival liver tissue may be clinically relevant in case of "occult" HCV infection or for the diagnosis of patients with known HCV infection and hepatic dysfunction but seronegative for HCV RNA. The assessment of the levels of HCV RNA in the liver might also be important for monitoring the effectiveness of antiviral therapy and the progression of disease in patients with chronic HCV hepatitis.

Liver HCV-antigens and steatosis in chronic hepatitis C: role of different genotypes

BACKGROUND

HCV infection is frequently associated with liver steatosis.

AIMS AND METHODS

We studied 126 frozen liver HCV positive specimens (genotype-3=27) without any features of metabolic syndrome, searching for a correlation between the number of HCV infected hepatocytes and the presence, amount and distribution of steatosis in relation to different genotypes.

RESULTS

Mean steatosis score was higher in genotype-3 with respect to non-3 (1.11 vs 0.66, p=0.022). HCV-antigens were detected by an immunoperoxidase technique in 91/126 (72.2%) cases. A significant correlation between the number of HCV-antigen positive cells and the degree of liver steatosis was observed in genotype-3 (p=0.01) but not in non-3 patients, matched for sex and age. Steatotic cells usually outnumbered HCV-infected cells. Steatosis was observed both in HCV-antigen positive and negative hepatocytes, and HCV-antigens were detected in both hepatocytes with and without steatosis: while no lobular codistribution was found in genotype non-3, in genotype-3 steatosis and HCV-antigens were usually found in the same areas.

CONCLUSION

Our data support the role of HCV-antigen liver expression in the pathogenesis of steatosis in genotype-3, however, since the presence of HCV-antigens is not directly related to steatosis within single hepatocytes, an indirect mechanism might be operative too.

Immunohistochemical staining of liver grafts with a monoclonal antibody against HCV-Envelope 2 for recurrent hepatitis C after living donor liver transplantation

AIM

We evaluated the expression of hepatitis C virus (HCV) antigen on liver grafts by immunohistochemical staining (IHS) using IG222 monoclonal antibody (mAb) against HCV-envelope 2 (E2).

METHODS

The study material was 84 liver biopsy specimens obtained from 28 patients who underwent living donor liver transplantation (LDLT) for HCV infection. The biopsy samples were examined histopathologically, and by IHS using IG222 mAb against HCV-E2. Serum HCV-RNA level was measured in all patients. The IHS grades were compared among the three groups classified according to the time elapsed from LDLT (at 1-30, 31-179 and > or =180 days post-LDLT) and among four post-transplant conditions, including acute cellular rejection (ACR).

RESULTS

Immunoreactivity to IG222 was detected in 78.6% of the specimens obtained during the first month after LDLT, and there were no significant differences on the IHS grades between the three groups classified according to the time elapsed from LDLT. The IHS grades were significantly stronger in definite recurrent HCV (n = 12) and probable recurrent HCV (n = 7) than in definite ACR (n = 7) and other complications (n = 8). There were no significant differences in serum HCV-RNA levels among the four post-transplant conditions. There was no significant correlation between the IHS grades using IG222 mAb and serum HCV-RNA levels when data of 84 liver biopsy specimens were analyzed.

CONCLUSIONS

Constant HCV-E2 expression was observed in liver biopsy specimens obtained 1 month or longer. The strong HCV-E2 expression on liver grafts were associated with recurrent hepatitis C after LDLT, but the serum HCV-RNA levels were not.

Composition of inflammatory infiltrate and its correlation with HBV/HCV antigen expression

AIM: To study the composition of liver inflammatory infiltrate in biopsy material from patients chronically infected with hepatotropic viruses and to evaluate the correlation of inflammatory infiltrate with hepatitis B virus (HBV) and hepatitis C virus (HCV) viral antigen expression in chronic B and C hepatitis.

METHODS: The phenotype of inflammatory cells was evaluated by the EnVision system, using a panel of monoclonal antibodies. HBV and HCV antigens were detected with the use of monoclonal anti-HBs, polyclonal anti-HBc and anti-HCV antibodies, respectively.

RESULTS: The cellular composition of liver inflammatory infiltrate was similar in the patients with B and C hepatitis: ~50%-60% of cells were T helper lymphocytes. Approximately 25% were T cytotoxic lymphocytes; B lymphocytes comprised 15% of inflammatory infiltrate; other cells, including NK, totalled 10%. Expression of HLA antigens paralleled inflammatory activity. Portal lymphadenoplasia was found more often in hepatitis C (54.5%) than in hepatitis B (30.6%). Expression of HBcAg was found more often in chronic B hepatitis of moderate or severe activity. Overall inflammatory activity in HBV-infected cases did not correlate with the intensity of HBsAg expression in hepatocytes. Inflammatory infiltrates accompanied the focal expression of HCV antigens. A direct correlation between antigen expression and inflammatory reaction in situ was noted more often in hepatitis C than B.

CONCLUSION: Irrespective of the etiology and activity of hepatitis, components of the inflammatory infiltrate in liver were similar. Overall inflammatory activity did not correlate with the expression of HBsAg and HCVAg; HBcAg expression, however, accompanied chronic hepatitis B of moderate and severe activity.

Tissue hepatitis C virus RNA quantification and protein expression help identify early hepatitis C virus recurrence after liver transplantation

We compared tissue hepatitis C virus (HCV) RNA polymerase chain reaction quantification and HCV immunohistochemistry (IHC) to histology in biopsy tissues in order to differentiate between acute rejection and HCV hepatitis recurrence early after orthotopic liver transplantation (OLT). We analyzed the first biopsy performed because of alteration of serum aminotransferases in 65 consecutive OLT patients with HCV genotype 1b. In the histological analysis, we quantified the portal tracts, Councilman bodies, Councilman body/portal tract (CP) ratio, steatosis, and Knodell and Ishak scores. The 52 patients (80%) with histological HCV recurrence [recurrence-positive (Rec+)] were separated from the 6 (9%) with acute rejection and the 7 (11%) with undetermined pathological features [recurrence-negative (Rec-)]. HCV RNA strongly correlated with HCV IHC, regardless of the histological diagnosis (P < 0.001). Both HCV RNA and HCV IHC were significantly associated with CP ratio (P = 0.041 and P = 0.008). No statistical correlation was found between HCV RNA, HCV IHC, and the other histopathologic features or the hepatitis scores. HCV RNA, HCV IHC, and CP ratio were the only variables able to discriminate between Rec+ and Rec- patients (Mann-Whitney test P < 0.001, P < 0.001, P = 0.014). In conclusion, a combined evaluation of histology, tissue HCV RNA, and HCV IHC significantly discriminated between OLT patients with or without HCV recurrence.

Detection of HCV antigens in liver graft: relevance to the management of recurrent post-liver transplant hepatitis C

The aim of this study was to evaluate how the immunohistochemical detection of liver hepatitis C virus (HCV) antigens (HCV-Ag) could support the histologic diagnosis and influence the clinical management of post-liver transplantation (LT) liver disease. A total of 215 liver specimens from 152 HCV-positive patients with post-LT liver disease were studied. Histologic coding was: hepatitis (126), rejection (34), undefined (24; coexisting rejection grade I and hepatitis), or other (31). The percentage of HCV-Ag infected hepatocytes were evaluated, on frozen sections, by an immunoperoxidase technique. HCV-Ag were detectable early in 57% of cases within 30 days post-LT, 92% of cases between 31 and 180 days, and 74% of cases after more than 180 days. Overall, HCV-Ag were detected more frequently in histologic hepatitis as compared to rejection (P < 0.0001) with a higher percentage of positive hepatocytes (P < 0.00001). In 16 patients with a high number of HCV-Ag-positive hepatocytes (65%; range 40-90%) a clinical diagnosis of recurrent hepatitis (RHC) was made despite inconclusive histopathologic diagnosis. Multivariate analysis identified the percentage of HCV-Ag-positive hepatocytes and the time post-LT as independent predictors for RHC (P = 0.008 and P = 0.041, respectively) and the number of HCV-Ag-positive hepatocytes >/=50% as the only independent predictor for nonresponse (P < 0.001) in 26 patients treated with alpha-interferon plus ribavirin. In conclusion, HCV reinfection occurs early post-LT, reaching its peak within 6 months. Immunohistochemical detection of post-LT HCV reinfection support the diagnosis of hepatitis when the histologic features are not conclusive. A high number of infected cells, independently from the genotype, represents a negative predictive factor of response to antiviral treatment.

Molecular mechanisms in hepatocellular carcinoma development

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world. It usually develops in patients with chronic viral hepatitis, aflatoxin exposure, or excessive alcohol use. Most patients with HCC present with advanced disease and have a poor prognosis. The implementation of antiviral drugs and the availability of a vaccine for hepatitis B should help reduce the incidence of HCC. Considerable effort has now focused on unraveling the molecular pathogenesis of HCC in order to design better treatments, or to prevent the disease altogether. However, so far, the pathogenesis of HCC appears to be quite heterogeneous among patients. In particular, several mechanisms of tumorigenesis seem to be involved, including loss of tumor suppressor gene function, oncogene activation, direct viral effects, DNA methylation, and angiogenesis. It is not clear which events are critical in tumor initiation versus tumor progression. RNA expression arrays and proteomics hold promise to provide further clues about this common and complex cancer.

Fibrosis is worse in HIV-HCV patients with low-level immunodepression referred for HCV treatment than in HCV-matched patients

Hepatitis C virus (HCV) infection is frequent in human immunodeficiency virus (HIV)-infected patients. It is known to have an aggressive course in significantly immunosuppressed patients, and cirrhosis C has become one of the main causes of mortality in HIV-HCV coinfected patients since the improvement of antiretroviral therapy. The reasons for this severe fibrotic evolution are unclear. This prospective study compared chronic HCV lesions, liver immunocompetent cells, fibrosis and liver HCV loads in 2 cohorts of naive patients referred for HCV treatment: 33 HIV-HCV coinfected patients with CD4 >250/microL and 33 HCV-infected patients matched for the main risk factors of fibrosis. Fibrosis, particularly perisinusoidal fibrosis, was more marked in the coinfected patients. This occurred in the absence of a significant difference in disease activity. The number of CD3+ cells in the liver was higher in the HIV-HCV patients than in the HCV patients. Conversely, the number of liver CD4+ cells was lower in HIV-HCV patients than in HCV patients. The numbers of CD8+ and CD68+ cells were similar in the 2 groups. Finally, liver HCV load, assessed by immunostaining and reverse-transcription polymerase chain reaction, was similar in the 2 groups. We conclude that in the population of HIV-HCV coinfected patients with low-level immunosuppression referred for HCV treatment, fibrosis is worse than in HCV patients and the proportion of CD4+ lymphocytes among CD3+ cells is markedly decreased in the liver, whereas intrahepatic viral load is similar. Our data confirm the need to treat such patients against HCV, and suggest that HIV infection could favor fibrosis via the modulation of the intrahepatic immune response.

Hepatocellular carcinoma: are we making progress?

Hepatocellular carcinoma is a very prevalent malignancy worldwide, with increasing incidence in the United States. Despite many available treatment options, the prognosis remains poor. Surgical resection or liver transplantation still represents the only potentially curative treatments for HCC. Until more effective systemic therapies are available, different localized treatment approaches will continue to be applied in the management of this disease. Although systemic chemotherapy has been disappointing, increased understanding of the tumor biology in HCC coupled with new drug development may lead to newer agents with novel mechanisms of action that are more efficacious. The poor treatment outcome and dismal prognosis make prevention of HCC an important strategy in controlling this aggressive type of malignancy. Vaccine programs for HBV are ongoing. Efforts are underway to develop a vaccine for HCV. Interferon therapy appears to decrease the risk of developing HCC in patients with hepatitis, especially those with HCV. A number of other approaches for decreasing risk in these patients as well as in those with alcoholic-related cirrhosis are currently being evaluated.

Hepatic immunohistochemical staining with a monoclonal antibody against HCV-E2 to evaluate antiviral therapy and reinfection of liver grafts in hepatitis C viral infection

BACKGROUND/AIMS

A simple and reproducible hepatic immunohistochemical staining (IHS) for hepatitis C virus (HCV) is not available. We aimed to validate hepatic IHS with monoclonal antibody (Mab) IG222, directed against the HCV-envelope 2 (E2) protein.

METHODS

A three-step indirect immunoperoxidase method was used for frozen sections and a two-step indirect EnVision technique was used for paraffin-embedded sections.

RESULTS

Naturally or in vitro HCV infected primary human hepatocytes were immunoreactive to HCV-E2. In the patient study (n=253), IHS had a sensitivity of 96% and a specificity of 91%. Six patients who showed positivity in the liver with Mab IG222, but remained anti-HCV and HCV-RNA negative, had hepatitis C-like changes in their liver biopsy. In one patient HCV-RNA could be detected in the liver biopsy. We confirmed early graft reinfection in patients transplanted for HCV-related disease (34 patients with serial biopsies). Treatment for acute cellular rejection with steroids was associated with an increase in staining intensity. In nine patients with clearance of HCV-RNA during antiviral therapy, seven achieved negativation of immunoreactivity and two a marked reduction.

CONCLUSIONS

The IHS with Mab IG222 is an accurate tool for diagnosis and clinical management of chronic hepatitis C.

The role of immunohistochemistry in diagnosis

Immunohistochemistry is a strong tool in hepatopathologic diagnosis: the technique is relatively simple and inexpensive. New and very sensitive detection methods have been recently developed (e.g., the EnVision technique and the microwave antigen retrieval method). This article discusses the role of immunohistochemistry in differentiating chronic cholestatic diseases from chronic hepatitis and in characterizing infectious agents. Algorythms for the typing of lymphomas and for the differentiation of primary tumors versus metastases are proposed as well. The immunohistochemical criteria for the diagnosis of premalignant lesions are discussed.

Timing of reinfection and mechanisms of hepatocellular damage in transplanted hepatitis C virus-reinfected liver

Pathogenic mechanisms and dynamics of hepatitis C virus (HCV) reinfection in orthotopic liver transplantation (OLT) are poorly defined. This study focuses on these aspects by studying 55 frozen biopsy specimens from transplant recipients with various histological diagnoses obtained from 4 days to 4 years post-OLT and 10 patients with HCV-related chronic hepatitis. The percentage of HCV-infected hepatocytes, number and distribution of CD8 and natural killer cells, and rates of hepatocellular apoptosis and proliferation were quantified by immunohistochemistry. HCV antigens were detected in 37% of biopsy specimens obtained within 20 days and 90% of biopsy specimens obtained from 21 days to 6 months after OLT. The number of HCV-infected hepatocytes was never less than 40% in acute hepatitis specimens and never greater than 30% in the other cases. Hepatocellular apoptosis was high in biopsy specimens of acute hepatitis and moderate in those from transplant recipients with normal histological characteristics, but still greater than in specimens of chronic active hepatitis. Proliferation correlated significantly with apoptosis. Lymphocyte infiltration was high and similar among cases of acute hepatitis, chronic hepatitis, and rejection. These data: (1) show that the detection of liver HCV antigens is sensitive enough to be used in clinical practice as a diagnostic tool to detect infection of the transplanted liver and might be useful, combined with conventional histological evaluation to detect hepatitic damage, for therapeutic decision making; (2) suggest direct cytotoxicity of HCV, as well as immunologic mechanisms possibly prevalent in chronic hepatitis and rejection, at least in the phase of acute massive liver infection; and (3) show that hepatocellular apoptosis and regeneration might be active enough to lead to replacement of the entire transplanted liver in 2 weeks.

Immunohistochemical detection of hcv in cirrhosis, dysplastic nodules, and hepatocellular carcinomas with parallel-tissue quantitative RT-PCR

Hepatitis C virus is a major risk factor for hepatocarcinogenesis in humans. In situ detection of the virus in early sequential lesions of hepatocarcinogenesis could provide information about the role of the virus in the transformation and promotion process. Parallel in situ detection of HCV proteins and RNA in human tissues were performed in 55 posthepatitis C cirrhosis, 17 dysplastic nodules (DN), and 25 hepatocellular carcinomas (HCC), using immunohistochemistry and tissue quantitative RT-PCR. A consistent cytoplasmic hepatocellular staining was obtained in 73% of cirrhosis cases (with or without HCC) and in 55% DN cases. A few tumoral hepatocytes were unambiguously stained in 28% HCC. The percentage of positive cells and the intensity of immunostaining significantly decreased from cirrhosis to HCC through DN, whereas there was no difference in the prevalence of positivity or the number of viral copies between cirrhosis and HCC using tissue-quantitative RT-PCR. Finally, RT-PCR levels were found parallel with the immunostaining in cirrhosis but not in HCC. These results suggest that HCV protein synthesis may persist but be down-regulated during sequential hepatocarcinogenesis. A putative role of HCV proteins on cell proliferation and differentiation during the early steps of carcinogenesis cannot therefore be excluded.

Genes and viruses in hepatobiliary neoplasia

Hepatobiliary neoplasms comprise a significant portion of the worldwide cancer burden. Advances in basic science research have led to rapid progress in our understanding of the molecular events responsible for these dreaded diseases. The genetic changes associated with hepatocellular carcinoma (HCC) have received the most attention. Aflatoxin B1 exposure leads to mutations in the p53 tumor suppressor gene, most commonly a transversion in codon 249 that leads to a substitution of serine for arginine in the p53 protein. Numerous other tumor suppressor genes, oncogenes, and tumor gene pathways are altered in HCC. Hepatitis B virus (HBV) infection is strongly associated with HCC. HBV may cause HCC either directly via the HBV X protein, or indirectly by causing liver inflammation and cirrhosis. Hepatitis C virus (HCV) infection is also associated with HCC. Recent evidence suggests that the HCV core protein may play a role in hepatocarcinogenesis. Several inherited metabolic diseases are associated with HCC. It is likely that these diseases cause HCC indirectly by causing cirrhosis. The molecular pathogenesis of cholangiocarcinoma and gallbladder cancer has not been well defined. However, multiple tumor suppressor genes and oncogenes, including p53 and K-ras, are altered in these tumors. Further molecular characterization of hepatobiliary tumors may lead to earlier diagnosis, better staging, improved treatment planning, and the development of more effective therapies.

Intragraft localization of activated nuclear factor kappaB in recurrent hepatitis C virus disease following liver transplantation

Nuclear factor kappaB (NF-kappaB) is activated during viral infection and is central to the regulation of host immune responses. The NF-kappaB activation status and its morphological sources were assessed by immunohistochemistry in allograft biopsy specimens of orthotopic liver transplantation patients with recurrent hepatitis C virus (HCV). Hepatocellular NF-kappaB immunostaining was detected in HCV cases compared with controls (nontransplant: P <.001; transplant: P =.006), which correlated with the number of NF-kappaB positive hepatocytes (P =.007) and contrasted to the absent to weak staining of controls (nontransplant: P =.001; transplant: P =.009). Enhanced NF-kappaB staining of cytokeratin 19-positive bile ducts and proliferating ductules in the HCV group was in contrast to controls. Intense NF-kappaB immunoreactivity was detected in CD68-positive Kupffer cells and macrophages of all HCV specimens compared with a few controls (nontransplant: P <.001; transplant: P =.001) and contrasted to the weak staining of controls (nontransplant: P <.001; transplant: P =.001). NF-kappaB-positive immunoreactivity correlated with the number of T cell receptor (TCR) alpha/beta-positive lymphocytes (P <.001), which was not observed in controls. In those HCV cases showing evidence of necroinflammatory activity (grade) and individual features of portal inflammation, periportal inflammation/piecemeal necrosis, lobular inflammation, and fibrosis (stage), higher NF-kappaB staining intensity scores within bile ducts, proliferating ductules, hepatocytes (piecemeal necrosis: P =.016; stage: P =.030), and lymphocytes (stage: P =.044) and increased number of NF-kappaB-positive cells within bile ducts, proliferating ductules (grade, lobular inflammation, piecemeal necrosis, stage: P =.022), hepatocytes, and lymphocytes were observed. Increased staining intensity and frequency of NF-kappaB-positive cells were similarly observed in HCV-positive allografts obtained from patients under tacrolimus- compared with cyclosporine-based immunosuppression. These data implicate an immunoregulatory role of intragraft NF-kappaB activation in the pathogenesis and progression of posttransplantation HCV disease recurrence.

Natural history and pathogenesis of hepatitis C virus related hepatocellular carcinoma

Generally, 0.4-2.5% of patients with chronic hepatitis C virus (HCV) infection develop hepatocellular carcinoma (HCC). HCC occurs more often in patients with cirrhosis and in those with increased liver cell proliferation. HCV-related tumors occur in older patients and often have a less aggressive course than HCC, related to other etiological factors. Many HCV-related HCC are multifocal in origin. However, many tumors grow as a single hepatic nodule for years before generating satellite or distant tumor nodules. The growth pattern varies from one tumor to another, with tumor volume doubling times ranging from 1 to 20 months. Tumor progression and hepatic failure are the leading causes of death in most patients. Using the polymerase chain reaction technique, HCV-RNA has been almost invariably detected in serum and tumor tissue of anti-HCV patients with HCC. In many patients, HCV-RNA was found to belong to the possibly more pathogenic type 1b. However, it is unlikely that HCV plays a direct role in liver tumorogenesis, since no reverse transcriptase activity has been found in infected livers. One current opinion is that HCV may promote cancer through cirrhosis, which is per se an important risk factor for this tumor. In HCV carriers, the risk of developing HCC and having more severe tumor disease may be increased by coexisting hepatitis B virus (HBV) or alcohol abuse, further supporting the idea that both HCC and cirrhosis might be a result of the interplay of several risk factors. HCC could also be the consequence of HCV interacting with cellular genes that regulate cell growth and differentiation, independent of the effect of cirrhosis.

Hepatitis C virus core protein binds to apolipoprotein AII and its secretion is modulated by fibrates

Several lines of evidence suggest that hepatitis C virus (HCV) core protein may modulate cellular transduction signals and alter lipid metabolism. We have investigated the binding of HCV core protein to cellular proteins by combining 2 yeast hybrid, confocal, and surface plasmon resonance assays. Our results show the direct binding of the viral protein to apolipoprotein AII (apoAII) and map the interaction domain to the C-terminal of HCV core protein. To investigate the biological relevance of the interaction between HCV core and lipid metabolism, we took advantage of the well-established increase in apoAII expression caused by fibrates in HepG2 cells. After fenofibric acid treatment, we show a parallel increase in apoAII and core protein secretion, this effect being abolished by brefeldin A. Our study identifies apoAII as one of the cellular targets for HCV core protein. We also show that the intervention of fenofibric acid in cellular lipid metabolism directly affects the expression pattern of HCV core protein.

Detection of hepatitis C virus in paraffin-embedded liver biopsies of patients negative for viral RNA in serum

The diagnosis of hepatitis C is based on serological testing for antibodies against various epitopes of the hepatitis C virus (HCV) and detection of HCV RNA in serum, because anti-HCV antibodies alone cannot discriminate patients who are infectious from those who have resolved the infection. If HCV RNA is not detected, which is the case in at least 20% of enzyme immunoassay (EIA)-positive patients, diagnosis remains unclear in a state of disease possibly well suited for therapeutic intervention. Therefore, we investigated if detection of HCV antigens or HCV RNA in routinely processed, formalin-fixed and paraffin-embedded (ffpe) liver biopsy specimens of patients positive for anti-HCV, but negative for HCV RNA in serum, could confirm diagnosis in this serological constellation. We detected HCV RNA by reverse-transcription polymerase chain reaction (RT-PCR) in 27 (61%) of 44 ffpe liver biopsies from EIA-positive, but HCV-RNA-seronegative, patients. Testing of 18 of these biopsies by a panel of polyclonal antibodies against structural and nonstructural HCV proteins revealed positive immunostaining in 6 cases (33%), which were also positive by RT-PCR. Most biopsies showed necroinflammation compatible with chronic hepatitis C, and the detection of tissue HCV RNA correlated significantly with a higher grade of inflammatory activity. Detectability of HCV RNA did not correlate with HCV subtype. In conclusion, the search for HCV RNA by RT-PCR within the liver biopsy specimen can establish rapid and unequivocal diagnosis of hepatitis C in at least 60% of anti-HCV antibody-positive patients who are seronegative for HCV RNA, and thus may help to avoid repeated testing and delayed therapy. Tissue RT-PCR may also be more efficient than serological testing for surveillance of interferon therapy response, because ongoing chronic active hepatitis C is clearly demonstrated in the absence of detectable serum HCV RNA.

Detection of virus-like particles in liver biopsies from HCV-infected patients

In order to directly ascertain the presence of HCV virus infection in livers of patients with HCV chronic hepatitis, we investigated, by transmission electron microscopy (TEM), liver biopsies from 2 adults and 4 children for the presence of virus-like particles (VLPs). The plasmas of these HCV-positive patients were HCV-RNA-positive, with high ALT values. In liver tissue samples examined, we were able to detect plus and minus strands of HCV RNA by strand-specific RT-PCR. Aggregates or single VLPs of about 45 nm in diameter were detectable in variable amounts in endoplasmic cisternae and in hepatocyte cytoplasms of infected patients. These results emphasize the relevance of performing TEM assays to confirm the diagnosis of HCV infection.

Hepatitis C virus dynamics in vivo: effect of ribavirin and interferon alfa on viral turnover

Treatment of patients with chronic hepatitis C with recombinant interferon alfa (rIFN-alpha) can cause a decrease of serum transaminases and hepatitis C virus (HCV) RNA. Recent trials evaluating combination therapy of IFN-alpha and ribavirin suggested a potential synergistic effect. From serial measurements of serum HCV RNA concentrations following treatment-induced perturbation of the balance between virus production and clearance, we compared the antiviral efficacy of both IFN-alpha alone and IFN-alpha in combination with ribavirin. Chronically HCV-infected patients were treated with either 3 x 3 MU or 3 x 6 MU rIFN-alpha per week or 3 x 6 MU rIFN-alpha plus 14 mg/kg of body weight ribavirin per day. The time-dependent HCV RNA concentrations during antiviral treatment were analyzed by iterative least-squares regression. After initiation of antiviral therapy, HCV RNA declined exponentially below the detection limit of the reverse-transcription polymerase chain reaction assay (1,000 HCV RNA molecules per milliliter) in 10 of 26 (39%), 10 of 19 (53%), and 10 of 18 patients (56%) treated with 3 x 3 MU, 3 x 6 MU rIFN-alpha without and with ribavirin, respectively. Viral clearance from serum was faster in patients treated with 3 x 6 MU rIFN-alpha (t1/2 = 0.23 +/- 0.15) compared with patients treated with 3 x 3 MU rIFN-alpha per week (0.67 +/- 0.36 days) (P < .004). However, half-lives of viral clearance were similar in patients treated with rIFN-alpha or rIFN-alpha plus ribavirin. For virus release from infected hepatocytes, absence and presence of ribavirin yielded half-lives of t1/2 = 2.54 +/- 2.10 and t1/2 = 1.99 +/- 1.70, respectively, indicating that ribavirin does not significantly inhibit HCV production. In conclusion, the data of the present study indicate that higher rIFN-alpha doses accelerate viral clearance from serum. Ribavirin (14 mg/kg/d), however, lacks synergistic antiviral effects in the treatment of chronic hepatitis C with 3 x 6 MU rIFN-alpha per week.

Recurrent hepatitis C virus infection after liver transplantation: immunohistochemical assessment of the viral antigen

BACKGROUND

The value of immunohistochemical methods to identify hepatitis C virus antigen (HCVAg) in liver tissue has not been established. We have evaluated the significance of HCVAg expression in livers of patients with transplants and recurrent hepatitis C virus (HCV) infection.

METHODS

Forty-two liver biopsy specimens from 32 liver-transplant recipients with recurrent HCV infection were tested for HCVAg using fluorescein isothiocyanate-labeled polyclonal, polyreactive human immunoglobulin. Histologic assessment of liver and quantitation of HCV RNA in sera were carried out in specimens obtained simultaneously with biopsies.

RESULTS

HCVAg was found in 33% of the liver specimens obtained during the first month after transplantation and in all liver specimens obtained between 1 and 18 months after transplantation. Amounts of the antigen were significantly greater in specimens obtained more than 1 month after transplantation. A statistically significant increase of the average HCV RNA level in serum was observed in samples tested after the first month after the transplantation, and some decrease in the HCV RNA level was found in those obtained between 6 and 18 months after transplantation. Larger amounts of HCVAg were observed in specimens corresponding to episodes of acute or chronic hepatitis than in those associated with minimal parenchymal evidence of rejection.

CONCLUSIONS

OBSERVATIONS of HCVAg expression in liver biopsy specimens indicated that the presence of viral antigens in hepatocytes is a constant finding in specimens obtained 1 month or longer after transplantation. Although large amounts of HCVAg correlated with acute or chronic hepatitis, the nature of this association with the development of pathologic changes remains to be established.

Histopathology of HCV infection

The basic morphologic features of acute and chronic viral hepatitis C are similar to those of other hepatitides; however, hepatitis C is characterized by the histologic triad of lymphoid aggregates in portal tracts, epithelial damage of small bile ducts and microvesicular and macrovesicular steatosis of hepatocytes. Significant progress has been made in the demonstration of HCV in infected liver tissues by immunohistochemical and in situ hybridization techniques. The new classification of chronic hepatitis, based on etiology, grading (extent of necroinflammatory activity) and staging (extent of fibrosis) has been widely accepted and will lead to a better understanding of the variable course and response to therapy of this enigmatic disease.

Clinical implications of GBV-C/HGV infection in patients with "HCV-related" chronic hepatitis

BACKGROUND/AIMS

To evaluate the clinical, biochemical and histological implications of a concomitant HGV infection in "HCV-related" chronic liver disease.

METHODS

Eighty-three HCV-RNA positive patients with chronic liver disease were tested for GBV-C/HGV coinfection by heminested PCR.

RESULTS

Twenty-two (26.5%) patients were found to be positive for GBV-C/HGV RNA. GBV-C/HGV+ patients differed significantly from GBV-C/HGV- ones for younger age, higher frequency of history of drug addiction, which in turn might favor coinfection with interferon-sensitive HCV genotypes (3a), and increased probability of long-term response to interferon. GBV-C/HGV infection appears to have no responsibility for specific aspects of HCV infection such as biochemical or histological cholestatic features, lymphoid follicles, symptomatic cryoglobulinemia or presence of serum autoantibodies, including LKM1. It does not worsen the HCV-related disease (ALT levels and histological activity) and does not significantly interfere with HCV infection, as explored by the number of hepatocytes positive for HCV antigens. The amount of steatosis (mean score) was shown to be higher in GBV-C/HGV+ patients. A virological follow up was performed in 17 interferon-treated GBV-C/HGV+ patients On the whole, GBV-C/HGV seems to be as sensitive to IFN treatment as HCV, but recurrence after withdrawal is more frequent. In spite of this, ALT levels often remain normal after treatment withdrawal.

CONCLUSIONS

The present data suggest that GBV-C/HGV infection, apart from more marked liver steatosis, does not modify the overall picture of chronic hepatitis due to HCV infection.

Quantitative liver parameters of HCV infection: relation to HCV genotypes, viremia and response to interferon treatment

BACKGROUND/AIMS

This study aimed to evaluate the relation between the number of hepatocytes positive for HCV antigens and the amount of HCV RNA in the liver and to evaluate the relationship between the above parameters and viremia levels, HCV genotype and response to interferon treatment.

METHODS

This was a retrospective study on 31 consecutive patients with chronic HCV-related liver disease, selected on the basis of the availability of frozen liver tissue for both liver HCV antigens detection and liver HCV RNA quantitation. HCV antigens (immunohistochemistry), liver and plasma HCV RNA (competitive RT-PCR), and HCV genotype (commercial kit) were studied.

RESULTS

A significant correlation (p=0.0005) was found between the amount of liver HCV RNA (log 10 copy/microg of extracted RNA) and the number of HCV-infected hepatocytes (scored from 0 to 3). These parameters were not significantly correlated with viremia levels. The highest liver HCV RNA levels and HCV antigen scores were found in patients infected with genotype 1b. Liver HCV RNA (median 541 x 10(3) vs 118 x 10(3) copy number/microg, p=0.031) and liver HCV antigens (mean score 2.3 vs 1.3, p=0.018) but not plasma HCV RNA (median 14956 x 10(3) vs 2885 [correction of 2.885] x 10(3) copy number/ml, ns) were significantly higher in patients not responding to interferon treatment compared to responders.

CONCLUSIONS

The tissue parameters tested in this study were significantly correlated, shared the same clinical implications and predicted short-term response to interferon treatment better than viremia levels. We suggest that these tests should be included in the study protocol of patients under evaluation for interferon treatment, basing the choice on local facilities.

Viral serology and detection

Viral detection is an important part of clinical hepatology. For many years practical clinical tests have been serological but recently newer molecular techniques have become available for virus detection, although these have yet to become routine and some, such as PCR of viral nucleic acid in blood or tissue are not yet consistently reliable. Serology remains the mainstay at present for routine diagnosis. Hepatitis A testing in clinical practice is entirely serological, the IgM response representing acute infection and the IgG response immunity, although more sophisticated molecular techniques have been applied experimentally. A second agent of epidemic enteral hepatitis, the hepatitis E virus, has recently been cloned and sequenced and serological tests for this virus are available, although experience in their use is necessarily limited and a commercial IgM assay has yet to be produced. Serological tests for the hepatitis B virus are well developed. The IgM anticore response differentiates acute infection from chronic, the latter being characterized by the persistence of hepatitis B surface antigen for over six months. Chronic carriers are at risk of liver damage and this risk is best assessed by the amount of viral DNA circulating, which can be determined using a hybridization assay. More sensitive techniques such as the branched chain DNA assay or PCR can detect lower levels of viral DNA but their clinical relevance remains to be established. The hepatitis D virus is defective and relies on hepatitis B to replicate. Serology for antibody and antigen is well established although PCR for circulating viral genome may come to supplant hepatic viral antigen as a test for hepatitis D replication. For hepatitis C serology is feasible only for antibodies, not antigens; although early tests were prone both to false positives and false negatives, current versions are more reliable. PCR has been much used for detection of hepatitis C RNA in blood and tissues and a bDNA assay is now commercially available. Cytomegalovirus detection is confounded by the problem of distinguishing asymptomatic viral replication from disease. Serology is helpful, especially in primary infections, but viral culture is a widely used method. PCR (especially quantitative modifications) or the pp65 antigenaemia assay are experimental approaches which may prove specific enough for general use.