High Hepatitis C Virus RNA Research Articles

Early HCV-associated stellate cell activation in aggressive recurrent HCV: What can liver allografts teach about HCV pathogenesis?

Early HCV-associated stellate cell activation in aggressive recurrent HCV: What can liver allografts teach about HCV pathogenesis?

Nonimmune complexed HCV RNA titer in serum as a predictor of interferon response in patients with chronic hepatitis C.

Hepatitis C virus (HCV) has been reported to exist in the circulation of patients in various forms such as free virions, immune complexes, and nucleocapsids. To clarify the clinical significance of serum HCV titers according to the forms of virus particles, we evaluated the immune complexed (IC) and nonimmune complexed (NIC) HCV RNA titers in 77 chronic hepatitis patients treated with interferon (IFN). IC and NIC forms in pretreatment serum were separated by immunoprecipitation using antihuman immunoglobulin antibody, and quantified by reverse transcription polymerase chain reaction. Serum titers of NIC HCV RNA were correlated with those of whole serum HCV RNA (r = 0.96, p < 0.01) and IC HCV RNA (r = 0.98, p < 0.01), but they were not with the aminotransferase levels, gamma-globulin concentration, and grading or staging of liver histology. Nonresponders to IFN had significantly high NIC HCV RNA titers compared with sustained responders (10(4.93 +/- 0.81) copies/ml vs 10(4.06 +/- 0.69) copies/ml, p < 0.01). It is noteworthy that the relative amount of NIC HCV RNA to whole serum HCV RNA was also significantly higher in nonresponders than in sustained responders (0.66 +/- 0.10 vs 0.50 +/- 0.11, p < 0.0001). Multivariate analysis showed that low NIC HCV RNA titer (p < 0.01) and genotype 2 (p = 0.02) were independent variables contributing to sustained response to IFN, but the whole serum HCV RNA titer was not. Pretreatment NIC HCV RNA titer is a more reliable predictive marker than genotype or whole serum HCV RNA of a sustained response to IFN monotherapy. This finding suggests that humoral immunity may affect the response to IFN.

Nonimmune complexed HCV RNA titer in serum as a predictor of interferon response in patients with chronic hepatitis C

Objective Hepatitis C virus (HCV) has been reported to exist in the circulation of patients in various forms such as free virions, immune complexes, and nucleocapsids. To clarify the clinical significance of serum HCV titers according to the forms of virus particles, we evaluated the immune complexed (IC) and nonimmune complexed (NIC) HCV RNA titers in 77 chronic hepatitis patients treated with interferon (IFN). Methods IC and NIC forms in pretreatment serum were separated by immunoprecipitation using antihuman immunoglobulin antibody, and quantified by reverse transcription polymerase chain reaction. Results Serum titers of NIC HCV RNA were correlated with those of whole serum HCV RNA ( r = 0.96, p < 0.01) and IC HCV RNA ( r = 0.98, p < 0.01), but they were not with the aminotransferase levels, γ-globulin concentration, and grading or staging of liver histology. Nonresponders to IFN had significantly high NIC HCV RNA titers compared with sustained responders (10 4.93 ± 0.81 copies/ml vs 10 4.06 ± 0.69 copies/ml, p < 0.01). It is noteworthy that the relative amount of NIC HCV RNA to whole serum HCV RNA was also significantly higher in nonresponders than in sustained responders (0.66 ± 0.10 vs 0.50 ± 0.11, p < 0.0001). Multivariate analysis showed that low NIC HCV RNA titer ( p < 0.01) and genotype 2 ( p = 0.02) were independent variables contributing to sustained response to IFN, but the whole serum HCV RNA titer was not. Conclusions Pretreatment NIC HCV RNA titer is a more reliable predictive marker than genotype or whole serum HCV RNA of a sustained response to IFN monotherapy. This finding suggests that humoral immunity may affect the response to IFN.

The effect of storage at different temperatures on the stability of Hepatitis C virus RNA in plasma samples

One important issue related to Hepatitis C virus (HCV) RNA nucleic acid amplification testing (NAT) is the storage conditions of plasma samples in order to obtain reliable results. Many authors have reported that the storage conditions could affect the RNA stability and, hence, HCV RNA detection. We have studied HCV RNA stability in plasma samples after storage at different temperatures (−70, −20, 5 and 25 °C). Samples containing different HCV titres were stored and analysed by qualitative or quantitative NAT techniques at defined time points. At −20 °C, samples containing high HCV RNA titres were followed-up during approximately 2.6–2.7 years, samples with intermediate concentrations during approximately 1 year and samples with 100 International Units/millilitre (IU/ml) during 2.5 years. Independently of the HCV RNA concentration, the results show absence of decay in HCV RNA detectability. Samples stored at 25 °C maintain their HCV RNA titre during 14 days and samples at 5 °C were stable for at least 3 months.

Analysis of Background Factors Influencing Long-Term Prognosis of Patients with Chronic Hepatitis C Treated with Interferon

Objective: Interferon (IFN) therapy has been used as antiviral therapy for chronic hepatitis C (CH-C); however, complete response to the therapy is observed in only about 30% of patients in Japan. Background factors involved in the responsiveness to IFN therapy, and progression to liver cirrhosis (LC) and hepatocellular carcinoma (HCC) after IFN therapy have not yet been sufficiently investigated. Methods: One hundred twenty-one patients with CH-C who received IFN therapy at Showa University Hospital between 1984 and 1999 were analyzed. Results: At 6 months after the termination of IFN therapy, 53 patients achieved a complete response, 11 patients incomplete response, and 57 patients no response. During a mean follow-up of 52.7 months, 12 patients progressed to LC, and 10 patients developed HCC. Multivariate analysis showed that significant independent factors involved in progression to LC were platelet count and the efficacy of IFN therapy. The significant independent factor involved in the development of HCC was platelet count. The factor involved in the therapeutic effect at 6 months after the termination of IFN administration was the serum hepatitis C virus (HCV) RNA levels before IFN therapy. Conclusion: Patients with high HCV RNA levels and low platelet counts should be considered to be at high risk of progressing to LC and developing of HCC and should be carefully followed after IFN therapy using ultrasonography, CT scan and MRI.

Hepatitis C virus core particle detected by immunoelectron microscopy and optical rotation technique

Hepatitis C Virus (HCV) are 55–65 nm spherical particles, but the internal structure of the virion remains to be clarified. To clarify the morphology of HCV core particles, we performed an immune electron microscopy (IEM) using plasma samples from two blood donors with high HCV RNA titers and a detergent-treated anti-HCV core antibody-free plasma sample with high HCV RNA titer (1.5×10 8 copies/ml). Spherical particles, with 33–40 nm in diameter (an average diameter of 37 nm) were found in 1.22–1.25 g/ml fractions after sucrose density gradient centrifugation by conventional electron microscopy (EM). IEM using rabbit polyclonal antibody (RR8) specific to the putative HCV core protein and goat anti-rabbit IgG colloidal gold particles revealed that these spherical particles specifically reacted with RR8. This finding indicates that the spherical particles are naked HCV core particles. Some of the HCV core particles had an icosahedron-like structure. Optical rotation technique showed that the HCV core particle exhibits six-fold symmetry and that the length of regular hexagon side is approximately 20 nm. These findings showed that HCV core particles are spherical particles of 33–40 nm in diameter and that HCV core particles may possess an icosahedron-like structure and a buoyant density of 1.22–1.25 g/ml.

Detection of hepatitis C virus in the bile and bile duct epithelial cells of hepatitis C virus–Infected patients

The pathobiology of hepatitis C virus (HCV) in the biliary system has not been clarified yet, although bile duct damage is a histological finding characteristic of chronic hepatitis C. In this study, we examined whether HCV infects bile ducts and is released into the bile. Twelve patients positive for serum HCV antibody were examined in this study, and eight were seropositive for HCV RNA by polymerase chain reaction (PCR). For those who underwent abdominal surgery, the bile was aspirated from the gall bladders by fine needle puncture. Five underwent wedge liver biopsy. Series of saline-diluted bile were assayed for HCV RNA by PCR to determine the HCV RNA titers. To examine HCV expression in the biliary system, the liver specimens were immunostained using monoclonal antibodies to the HCV proteins. HCV RNA was detected in the bile of 5 patients with high serum HCV RNA load (≥2.5 Meq/mL). Comparison of viral loads between serum and bile revealed that the HCV RNA level in the bile was as high as that in serum. Furthermore, immunohistological study showed that bile duct epithelial cells were infected with HCV. In contrast, HCV was not found in either the bile or bile duct of patients seronegative for HCV RNA or with low serum HCV load (≤1.1 Meq/mL). These findings suggest that the biliary system is involved in the pathobiology of HCV and that the bile is as highly infectious as the serum. (HEPATOLOGY 2001;33;977-980.)

High levels of hepatitis C virus RNA in native livers correlate with the development of cholestatic hepatitis in liver allografts and a poor outcome.

A subset of hepatitis C virus (HCV)-positive liver transplant recipients develop cholestatic hepatitis (CH). We investigated the role of pretransplantation disease activity (estimated by Knodell score and HCV RNA quantitation) in the native liver explant on the development of CH and graft and patient outcome. Eight patients with CH were identified among HCV-positive liver transplants and were compared with 20 consecutive patients with recurrent HCV hepatitis of noncholestatic type in liver transplants. We evaluated all 28 explanted native livers histologically using the Knodell scoring system. HCV viral load was measured in the native explant and 5 allograft explants from the CH group using Amplicor HCV RNA Monitor test. Six of 8 patients with CH had HCV RNA levels of 5,000 copies/microg of DNA or greater in the native liver explant, whereas only 1 of the control group had viral loads greater than this level. Greater HCV RNA levels correlated with worse graft and patient survival (P <.001). The 3-year survival rate in the CH group was 18% compared with 77% in the control group (P <.001). There was no difference in the primary immunosuppressive regimens used in the 2 groups. We conclude that (1) CH has a uniformly poor prognosis, (2) type of immunosuppressive therapy appears to have little influence on the development of CH, (3) high pretransplantation HCV RNA levels in the native explant may predict the development of CH, and (4) patients with high HCV RNA levels in the explanted native liver may be appropriate candidates for antiviral therapy to prevent the development of CH.

Assessment and treatment of liver disease in Japanese haemophilia patients.

We studied the prevalence of the hepatitis C virus (HCV), human immunodeficiency virus (HIV) and GB virus C or hepatitis G virus (GBV-C/HGV), and characteristics of infections in Japanese haemophilia patients. Haemophilia patients were highly infected with HCV (88.2%) because of frequent use of unheated blood concentrates. Analysis for HCV genotypes revealed characteristics of HCV infection in haemophilia patients. Japanese haemophilia patients were highly infected with rare genotypes in Japan: genotype 1a (26.5%), genotype 3 (14.5%) and genotype 4 (2.4%). HIV infection was observed in 32.3% of haemophilia patients. HCV quasispecies (clones) and direct sequencing were investigated in patients with a single HCV genotype in the hypervariable region 1 of HCV, which resulted in a high degree of diversity. This indicates that even a single genotype of HCV might have multiple origins. GBV-C/HGV infection was noted in 20.9% of Japanese haemophilia patients. Over 40 haemophilia patients with chronic hepatitis C have been treated with interferon alpha for 6 months at total doses of 480-720 million units. About 38% showed clearance of HCV RNA from serum. Six patients with HIV infection were included in the study and they did not show eradication of HCV from the serum. This might derive from that they had high serum HCV RNA titers and genotype 1a or 1b. Histologic assessment was performed in 36 haemophilia patients with HCV. No case showed a histologically normal liver. Hepatic fibrosis in the biopsy specimens was classified into five stages of fibrosis and compared with serum hepatic fibrosis markers. Serum hyaluronic acid mostly correlated with hepatic fibrosis (r = 0.78, P < 0.0001) followed by type IV collagen (r = 0.38, P < 0.05). This suggests that estimation of serum fibrosis markers might be substituted for liver biopsy in haemophilia patients.

Discordance between serum alanine aminotransferase (ALT) and virologic response to IFN-alpha2b in chronic hepatitis C patients with high and low pretreatment serum hepatitis C virus RNA titers.

Although serum alanine aminotransferase (ALT) and hepatitis C virus (HCV) RNA concentrations are primary markers used to assess the clinical benefit of interferon (IFN) therapy in patients with chronic HCV infection, discrepancies between these two variables exist. In this study, 103 patients with chronic hepatitis C were treated with 3 MIU IFN-alpha2b three times weekly for 24 weeks, followed by 24 weeks of observation. ALT and virologic responses were compared in patients with high pretreatment HCV RNA titers (defined as pretreatment HCV RNA concentrations at or above the 75th percentile of the distribution or >5,000,000 copies/ml) and low pretreatment HCV RNA titers (defined as pretreatment concentrations below the 75th percentile or < or =5,000,000 copies/ml). Analysis of the virologic response for the high-titer and low-titer groups demonstrated a significantly greater HCV RNA sustained response in the low-titer group (21%) compared with the high-titer group (7%) (p < 0.05). In contrast, the ALT sustained response was not significantly different between the low-titer group (21%) and the high-titer group (18%). Analysis of the correspondence between biochemical and virologic responses showed that only 38% of patients with high pretreatment HCV RNA titers had both a sustained ALT response and a sustained loss of HCV RNA compared with 75% of patients with low pretreatment HCV RNA titers. The level of agreement between the ALT and HCV RNA responses was greater for the low-titer group compared with the high-titer group (kappa = .6848 and kappa = .4966, respectively). Our results indicate that chronic HCV patients with high pretreatment HCV RNA titers showed greater discordance between sustained ALT and HCV RNA responses compared with patients with low pretreatment HCV RNA titers and that measurement of HCV RNA should be included in the assessment of response to IFN therapy in chronic hepatitis C patients.

Cholestatic hepatitis after liver transplantation is associated with persistently high serum hepatitis C virus RNA levels.

Viral recurrence is universal after transplantation for hepatitis C infection. This may lead to difficulties in differentiating allograft dysfunction caused by chronic rejection from hepatitis C virus (HCV) recurrence. Cases of severe cholestatic hepatitis have also been reported in conjunction with reinfection of the graft with HCV. Patients receiving transplants for HCV-related liver disease were studied before and after transplantation by HCV RNA quantitation of serial serum samples. Four major clinical patterns of HCV recurrence could be distinguished posttransplantation: group 1, asymptomatic hepatitis with no significant symptoms; group 2, cholestatic hepatitis with centrilobular ballooning; group 3, hepatitis leading to chronic allograft rejection; and group 4, persistently normal serum aminotransferase levels. Pretransplantation viral load was shown to be an important indicator of disease severity because the group 2 patients had significantly higher pretransplantation viral loads than patients in group 1 (P = 0.01) and group 4 (P = 0.005). The group 2 patients also had persistently significantly higher posttransplantation viral loads than the patients in group 1 (P = 0.01) and group 4 (P = 0.02), whereas patients who developed chronic allograft rejection showed marked decreases in serum HCV RNA before retransplantation. Patients from group 4 had the lowest viral loads after transplantation. These results show that persisting graft cholestasis due to HCV is associated with persistently high HCV RNA levels compared with other etiologies of graft dysfunction. Prospective studies are needed to determine whether such quantitation may be diagnostically helpful in distinguishing the different patterns of HCV-related graft dysfunction observed after liver transplantation.

Significance of IgM anti-HCVcore level in chronic hepatitis C

Aim: To investigate the significance of IgM antibody to hepatitis C virus (HCV) core antigen (IgM anti-HCVcore) in chronic hepatitis C.Methods: In a group of 112 patients with histologically proven chronic hepatitis C positive for HCV RNA, IgM anti-HCVcore level was studied by a sensitive semi-quantitative enzyme immunoassay. Quantitation of serum HCV RNA was done by a second generation bDNA assay and determination of HCV genotype by RT-PCR and reverse hybridization.Results: IgM anti-HCVcore was detected in 72 (64.3%) of the 112 patients. ALT levels were significantly higher in IgM anti-HCVcore positive than negative patients. No other significant difference was observed in any of the patients' characteristics between IgM anti-HCVcore positive and negative groups. On the contrary, IgM anti-HCV core level was found to be significantly higher in female than in males, in patients with moderate or severe chronic hepatitis, in patients with high HCV RNA levels and in patients infected with HCV genotype 1b. Moreover, IgM anti-HCVcore level was significantly correlated with age and ALT level. Multiple regression analysis showed that IgM anti-HCVcore level was significantly related only to the HCV genotype (p=0.001), histological grade (p=0.017) and ALT level (p=0.038).Conclusions: Our data support the hypothesis that IgM anti-HCVcore level is associated mainly with HCV genotype and secondly with liver disease necro-inflammatory activity. These associations may have implications in the pathogenesis of chronic hepatitis C.

Hepatitis C serotypes in nonalcoholic and alcoholic patients.

Genotyping of the hepatitis C virus (HCV) RNA can be performed by a variety of methods following polymerase chain reaction amplification of a stable RNA portion of the genome. The gold standard is amplification of the RNA from the NS5 region, followed by direct sequencing and homology comparison. This method is extremely labor intensive. In this study, we compared an immunoblot serotyping technique (HCV SIA) to a reverse-hybridization line-probe assay (LiPA) for genotype classification among non-alcoholic HCV infected patients. We then compared and contrasted the response in this cohort to a population of alcoholic patients with HCV infection. To validate the serotype assay, sera from 110 patients with chronic HCV infection was utilized. Serotyping (Chiron SIA) and genotyping by the LiPA (Line Probe Assay, Innogenetics) reverse-hybridization technique was performed. Additionally, both methods were compared to sequence-derived genotyping in 26 patients based on PCR amplification of the NS5 region. After the validation phase, sera from 105 alcoholic patients was genotypically classified by the serologic method. The nonalcoholic and alcoholic groups were then compared with regard to serotype, demographics, and frequency of untypable test results. Among typable pairs, the overall concordance rate between serotyping and LiPA-based genotyping was 93.75%. Patients with genotype 1 by reverse hybridization demonstrated a 95.8% concordance with serotype. Untypable samples were present for both techniques, but since they occurred in different patients, the techniques were complementary. Alcoholic patients were significantly more likely to be infected with untypable serotypes than those without a pattern of alcohol abuse. These patients were also more likely to be HCV RNA negative than sera from typable patients. Serotype 1 was associated with high HCV RNA titer and poor interferon treatment response among both nonalcoholic and alcoholic patients. An immunoblot method for the evaluation of genotype classification was rapid and easily performed compared to sequence-based genotyping. There was a high degree of concordance compared to reverse-hybridization and sequence-based genotype characterization methods. Failure to detect HCV RNA in the serum is associated with a higher likelihood of classification failure. This problem was particularly prevalent in the alcoholic population. HCV RNA titers and treatment outcomes were strongly associated with serotype classification results, demonstrating clinical utility of this assay technique.

中華民國小兒科醫學會第145屆學術演講會 教育演講：兒童疾病的新境界—C型肝炎病毒之母子傳染

Mother-to-infant transmission of hepatitis C virus (HCV) does occur in a lower efficiency way(0-15％,average in 4.7％)in infants of HCV viremic mothers than that of hepatitis B virus. It is very likely due to the lower viral level of mothers. Infants of mothers coinfected by HCV and human immunodeficiency virus (HIV), or with high HCV RNA titer (＞10^6 copies/ml) are at high risk of HCV infection by their mothers. Persistence of HCV infection with transient or persistent abnormal aminotransferase levels occurred in most(81％) HCV infected infants studied longitudimally, although normal liver function profile was also observed. Up to now, no effective way can prevent mother-to-infant transmission of HCV. Further investigation to understand more the natural history of infants perinatally infected by HCV and the indication for antiviral therapies are needed.

Hepatitis C plasma viral load is associated with HCV genotype but not with HIV coinfection.

The influence of human immunodeficiency virus (HIV) coinfection and hepatitis C virus (HCV) genotype distribution on HCV viral load and alanine amino transferase (ALT) levels in chronically infected patients remains unclear. In the present study, serum samples from a group of haemophiliac patients were investigated retrospectively. HCV geno- and subtyping was carried out using the Inno line probe assay (Inno LIPA, Innogenetics, Zwijnaarde, Belgium) in 87 patients positive by HCV RT PCR. Of these patients, 31 (35.6%) were HIV coinfected. HCV RNA was quantified with the HCV Monitor kit (Roche, Basel, Switzerland) in 43 patients (22 HIV-negatives, 21 HIV-positives). The most prevalent genotypes were 1 (n = 52) and 3a (n = 16) followed by genotype 2 (n = 9) and 4 (n = 3). Mixed infections were detected in 7 patients. Of genotype 1 positive samples, 24 and 23 were classified as subtype a and b, respectively. Five samples could not be subtyped. Although higher mean values of ALT were observed in genotype 1 infected patients, there was no statistically significant association between HCV genotype or subtype and liver enzymes (P > 0.05). On the other hand, statistically significant higher HCV RNA titres were observed in haemophiliacs infected with HCV genotype 1 in comparison to those infected with other genotypes (P < 0.01). No relationship was found between the presence of HIV coinfection and viral load of HCV RNA. There was no evidence that HCV infection had a more severe outcome in HIV-positive patients who had been infected with HIV and HCV more than ten years ago, even in those with very low CD4+ cell counts. No clear association between high ALT levels and large amounts of viral RNA was observed. In conclusion, a large viral load is associated with HCV genotype 1 infection; HIV coinfection has no clear effect on the intensity of HCV replication. An ongoing prospective study will evaluate the respective role of viral load, genotype, HIV coinfection and ALT level in the response to interferon therapy.

Mother-to-infant transmission of hepatitis C virus

Mother-to-infant (vertical) transmission of hepatitis C virus (HCV) has been documented but vertical transmission of HCV is less efficient (affecting 0% to 15% [mean 4.7%] of the infants of mothers with HCV infection) than that of hepatitis B virus. This lower rate of vertical transmission is likely due to the lower viral level of HCV in the sera of most mothers with an infection. Infants of mothers with an HCV and HIV coinfection or with a high HCV RNA titre (greater than 1 million copies per millilitre) are at a high risk of HCV infection (with a mean 39% of infants of mothers with HCV and HIV coinfection having an HCV infection). In most infants (81%) with an HCV infection studied longitudinally, the infection is persistent, and the alanine aminotransferase levels are transiently or persistently abnormal; however, normal liver function is also observed in some patients. There is currently no effective way to prevent vertical transmission of HCV. Further investigation aimed at better understanding the natural history of perinatal HCV infection and the indications for antiviral therapy is needed.

Quantitative branched DNA assay and genotyping for hepatitis C virus RNA in Chinese patients with acute and chronic hepatitis C.

To determine the value of a quantitative branched DNA (bDNA) assay for detection of hepatitis C virus (HCV) RNA, 309 serum specimens were collected from 100 patients with acute or chronic hepatitis C for detection of HCV RNA by bDNA assay and reverse transcription-polymerase chain reaction (RT-PCR) assay. There were 256 samples positive by RT-PCR; 199 (78%) were also positive by bDNA assay. All but 1 of the remaining 53 samples negative by RT-PCR were also negative by bDNA assay. Combination of the two methods clearly demonstrated changes in HCV RNA titers during and after interferon (IFN) treatment. The most common genotype of HCV infection was Okamoto type II (Simmonds type 1b, 60.0%), followed by type III (type 2a, 16.5%) and type IV (type 2b, 8.2%); mixed or underdetermined types were noted in 15.3%. Patients with chronic type II HCV infection tended to have higher HCV RNA titers. These findings suggest that the bDNA assay is a reliable test for HCV RNA.

Hepatitis C virus antibodies, viral RNA and genotypes in sera from patients on maintenance haemodialysis.

Patients on maintenance haemodialysis in four dialysis centres were tested for markers of hepatitis C virus (HCV) infection. Antibody to HCV (anti-HCV) was detected by the second-generation enzyme immunoassay in 142 (26%) of the 543 patients and HCV RNA in 117 (22%) of whom four were without detectable anti-HCV in serum. Seventy-seven (66%) were infected with HCV of genotype II/1b, 31 (27%) with genotype III/2a and eight (7%) with genotype IV/2b, in a distribution similar to that in blood donors who carried HCV asymptomatically. Haemodialysis patients had high HCV RNA titres comparable to those of patients with chronic hepatitis C. HCV RNA was detected in 96 (26%) of the 365 patients with a history of transfusion more frequently than in 21 (12%) of the 178 without previous transfusion (P < 0.001). In transfused patients, frequencies of anti-HCV and HCV RNA increased in parallel with the duration of haemodialysis. The frequency of anti-HCV in non-transfused patients, however, did not change appreciably with the duration of haemodialysis up to 22 years. The patients with anti-HCV had a higher frequency of HCV RNA in serum than symptom-free blood donors with anti-HCV (113/142 or 80% vs 109/166 or 66%, P < 0.01) and the patients with HCV RNA had a lower frequency of elevated aminotransferase levels than blood donors with HCV RNA (5/113 or 4% vs 27/109 or 25%, P < 0.001). These results indicate that transfusion is a significant cause of HCV infection in patients on maintenance haemodialysis, and that these patients are prone to establish the HCV carrier state after infection.

Interferon therapy in chronic hepatitis C virus infection

Antiviral treatment of chronic hepatitis C with interferon is reviewed. Alpha-interferon, both recombinant alpha-2a, -2b and human lymphoblastoid interferon given at a dose of > or = 3MU t.i.w. for 6-12 months will result in normalisation of ALT levels (complete response) in some 50-60% of treated patients with chronic hepatitis C virus (HCV) infection. Approximately half of the complete responders to interferon will relapse within 6 months once treatment is withdrawn (non-sustained response). Longer treatment schedules (6 vs. 12 months) seem to diminish the relapse rate and increase the percentage of sustained response. In patients with sustained response to interferon treatment with continuously normal ALT levels > or = 6 months after treatment stop a concomitant eradication of the viraemia is usually seen, whereas a non-sustained or non-response to interferon usually will indicate a continuous viraemia. Factors predictive of a favourable response are low pretreatment HCV RNA levels in serum, genotypes other than type II according to Okamoto, short disease duration, female gender and less pronounced liver damage, whereas high serum HCV RNA levels, having genotype II and cirrhosis, are predictive of a less favourable response. Patients with a sustained response and eradication of the viraemia will also improve their liver inflammation with diminishing scores for portal inflammation, piecemeal necrosis, lobular inflammation and also fibrosis after treatment. For non-responders and non-sustained responders to interferon, ribavirin especially in combination with interferon will offer some hope for the future.

Hepatitis C virus particle detected by immunoelectron microscopic study.

To clarify the morphology of hepatitis C virus (HCV), an indirect immunogold electron microscopic study was carried out on two plasma samples with high HCV RNA titres using polyclonal and monoclonal antibodies specific to the putative HCV envelope protein. Spherical virus-like particles, 55 to 65 nm in diameter with spike-like projections, were found in 1.14 to 1.16 g/ml fractions after sucrose density gradient centrifugation. These particles were found only in HCV-infected blood donors and had morphological features similar to those of flaviviruses. Moreover, these particles specifically reacted with the polyclonal and monoclonal antibodies to the putative HCV envelope protein. This is the first known report in which the morphology of the HCV particle is clearly shown.