Typing hepatitis C virus by polymerase chain reaction with type-specific primers: application to clinical surveys and tracing infectious sources

Rapid genotyping of hepatitis C virus RNA-isolates obtained from patients residing in western Europe

Two rapid genotyping methods for hepatitis C virus (HCV), the line probe assay (Inno-LiPA) and the subtype-specific core amplification system [Okamoto et al., (1992b) Journal of General Virology 73:673-679], were applied to 58 HCV isolates which were typed as type 1 (n = 37) and type 2 (n = 21) by sequence analysis of the 5' untranslated region (5'UTR). The line probe assay targets the 5'UTR and recognized 12 subtype 1a, 25 subtype 1b, 18 subtype 2a, 2 subtype 2b and 1 subtype 2d in accordance with sequence analysis of this region. Subtype-specific core amplification revealed 7 discrepancies among the 37 type 1 isolates when compared to LiPA. A different subtype was observed in 3 isolates (1a versus 1b), 2 isolates remained untyped and 2 isolates showed a coinfection of subtype 1a and 1b. The first 5 discrepancies were confirmed by sequence analysis of the core region whereas the coinfection could not be confirmed. Of the 21 type 2 isolates only one could be typed by subtype-specific core amplification. HCV RNA was detected in all 21 cases after the general first round of polymerase chain reaction (PCR). Direct sequencing of the core region indicated sequence variation as a source of failure. It is concluded that LiPA results are conclusive for typing of HCV. However, LiPA is hampered occasionally for subtyping by lack of subtype-specific sequence variation in 5'UTR. Subtyping results by subtype-specific core amplification were accurate. However, it seems that this assay is not suitable for the identification of genotype 2 isolates that circulate in patients living in Western Europe.

Genomic characterization of hepatitis C virus isolates from Argentina

Thirty-three Argentinian patients infected with hepatitis C virus (HCV) were studied for viral genotyping. The patients included 10 hemophiliac and 4 polytransfused children and 19 adults: 3 polytransfused, 7 dialyzed and 9 sporadic cases. Core-based genotyping permitted the classification of 31 samples. Genotypes II, I and V were the most frequent: 21 (63.6%), 16 (48.4%) and 10 (30.3%) of the 33 patients, respectively. Only one polytransfused patient carried genotype IV. Genotype II was detected in 7 out of 9 sporadic cases. Thirteen patients (39.3%) were coinfected with two genotypes, and 2 others were coinfected with three genotypes. The remaining 2 samples which could not be typed were characterized following the restriction fragment length polymorphism (RFLP) method, and were classified as type 1. One of these had two consecutive transitional mutations in the 5' untranslated region (5' UTR).

Rapid HCV RNA detection by PCR followed by a new non-radioactive liquid hybridisation assay and comparison with RIBA

A one-stage polymerase chain reaction (PCR) followed by an automated liquid hybridisation assay was used to examine anti-HCV-positive patients. The presence of HCV-RNA in 251 randomly selected enzyme immunoassay (EIA) positive clinical specimens was compared to their RIBA pattern. An association of a RIBA pattern with presence or absence of HCV-RNA was not detected. One hundred of these samples were also evaluated after dividing them into normal and elevated serum alanin aminotransferase (ALT) levels. PCR results were obtained on the basis of amplification products from two different gene regions (5'-NC region and NS 3). To prove the specificity of the PCR products, a commercially available digoxigenin-based liquid hybridisation assay was evaluated. The sensitivity was comparable to the results obtained after nested PCR. Based on the results of the study, the two-stage PCR can be changed in favour of the easier one-step PCR which offers the advantage of fewer contamination problems.

Serum levels of soluble interleukin-2 receptor in chronic hepatitis C treated with interferon-alpha

BACKGROUND

Serum levels of soluble interleukin-2 receptor (sIL-2R) seem to serve as a marker for the activation of T lymphocytes. The aim of this study was to evaluate the clinical significance of such levels in patients with chronic hepatitis C (CHC) treated with interferon.

METHODS

We measured serum levels of sIL-2R in 37 patients with CHC before and after treatment with recombinant interferon-alpha. Serum receptor levels were then compared with the response of the hepatitis C virus (HCV)-RNA level in serum after interferon.

RESULTS

Receptor levels were significantly higher in the patients with chronic persistent hepatitis and chronic active hepatitis than in normal controls (p < 0.01). There was a weak correlation between serum sIL-2R and alanine aminotransferase (ALAT) levels (r = 0.14, p = 0.010). Patients were then classified into three groups on the basis of the effect of interferon treatment on HCV-RNA levels in serum: sustained response (SR; n = 21), non-sustained response (NSR; n = 14), and nonresponse (NR; n = 2). Before and during interferon treatment the serum sIL-2R level remained increased in the SR group and in the combined groups with NSR or NR. However, after interferon was withdrawn, the serum sIL-2R decreased in the SR group but remained significantly increased in the combined response group (p < 0.01-0.05).

CONCLUSION

This finding seems to reflect the disappearance of HCV-RNA from the serum of the patients with an SR, and monitoring of sIL-2R levels may therefore be of value as an adjunct to the measurement of serum ALAT and HCV-RNA in evaluating the response to the interferon therapy for CHC.

Relation between serum hepatitis C virus-RNA levels and efficacy of interferon-beta therapy

We performed two courses of interferon-beta (IFN-beta) to a child with chronic hepatitis C. A complete response was not obtained by the first interferon treatment, however, the results of the second treatment differed from those of the first. Hepatitis C virus (HCV)-RNA remained negative and both aspartate aminotransferase and alanine aminotransferase levels remained normal after completion of the second course. From these results we estimated that HCV-RNA levels before IFN therapy could be significantly associated with the efficacy of this treatment. The serum level of HCV-RNA was 10(6) copies/50 microL before the first treatment, but was 10(3) copies/50 microL before the second course. We conclude that IFN therapy to children with hepatitis C should always be directed at providing a cure. Even if the clinical effects of the first course are minimal decreasing quantities of HCV-RNA still offer hope for cure by subsequent readministration.

Changes in blood lipid composition and response to interferon treatment in chronic hepatitis C

To assess whether the initial status of lipid metabolism in patients with chronic viral hepatitis might correlate with outcome of therapy, 52 patients (32 males and 20 female) with chronic hepatitis C were studied: 44 were treated with human recombinant interferon-alpha 2b (3 MU three times per week for up to 12 months), and 8 served as controls. At baseline, sera were tested for total and HDL cholesterol, HDL2, HDL3, apolipoprotein A-I, apolipoprotein B, interferon-alpha, tumor necrosis factor, and interleukin-6. Changes in blood lipids were evaluated after 3, 30, and 90 days of treatment. HDL cholesterol, apolipoprotein A-I, and HDL3 decreased by 9.4-11.4% within 4 weeks of starting interferon treatment, but this effect was sustained only in patients with a primary response to interferon. On multivariate analysis, a primary response to interferon correlated with higher apolipoprotein A-I and lower (< 2.23 pg/ml) interleukin-6 levels (p < 0.005 for both). In contrast, a sustained response was significantly more common in patients with low (< or = 13.3 pg/ml) serum interferon-alpha and lower interleukin-6 at baseline but did not correlate with any of the blood lipids. Thus, in chronic hepatitis C, interferon treatment induces specific changes in blood lipids. The concentration of apolipoprotein A-I at baseline is a strong predictor of primary response to treatment, and the likelihood of sustained response seems to be reflected by lower cytokine activation.

Clinical and virological findings in mixed cryoglobulinaemia

OBJECTIVES

As a close relationship has been established between mixed cryoglobulinaemia and hepatitis C virus (HCV) infection, the clinical, histological and virological findings of patients affected by mixed cryoglobulinaemia were determined.

DESIGN

Hepatitis C virus infection was investigated by the presence of anti-HCV antibodies and PCR amplification of the 5' untranslated region (5' UTR), and the genotype of HCV was also determined according to Okamoto. A bone marrow biopsy was performed in all patients and liver and kidney biopsies when indicated.

SUBJECTS

Eighty-two subjects affected by mixed cryoglobulinaemia were enrolled in this study.

RESULTS

The prevalence of anti-HCV antibodies was high (83%); PCR amplification of the 5'UTR region was performed in 52 subjects and in 44 of them (85%) the results were positive. In the same subjects, the Core region amplification was positive in 46 cases (88%). A high prevalence of genotype II was found (54%). Chronic liver disease was present in 55 patients (67%). Bone marrow biopsies showed the presence of low-grade non-Hodgkin's lymphomas in 11 cases (13%). Membrano-proliferative glomerulonephritis was found in seven subjects (8%).

CONCLUSIONS

Mixed cryoglobulinaemia is associated with HCV infection in the nearly all cases. Several HCV genotypes are involved in the pathogenesis of this disease. Mixed cryoglobulinaemia is associated with a high prevalence of chronic liver disease, low-grade non-Hodgkin's lymphomas and membrano-proliferative glomerulonephritis.

Clearance of serum hepatitis C virus RNA after interferon therapy in relation to virus genotype

The effect of recombinant interferon-alfa on serum HCV RNA levels in Japanese patients with chronic hepatitis C was investigated. At 24 weeks of treatment, 41 (32.5%) of 126 patients lost HCV RNA from serum, and aminotransferases were normalized in 31 (75.6%) of these 41 cases. HCV genotypes were categorized into four types (Type I, II, III, IV); the frequencies among the patients were: Type I: 0%, Type II: 70.6%, Type III: 20.6%, and Type IV: 6.3%. At the end of the 24-week treatment, HCV RNA levels were remarkably decreased in Type III patients and became undetectable in 18 (69.2%) of 26. In contrast, only 18 (20.2%) of 89 patients with Type II and two of eight with Type IV lost HCV RNA from sera. The relation between HCV genotype (Type III) and response to IFN therapy was also confirmed using a logistic regression model. HCV genotype seems to be an important factor in determining the response to IFN in patients with chronic hepatitis C.

Persistent hepatitis C virus infection after liver transplantation: clinical and virological features

We report a prospective clinical and virological study of 18 patients undergoing orthotopic liver transplantation, selected because of hepatitis C virus (HCV) RNA positivity before transplantation. Nine of the 18 patients (50%) developed chronic active hepatitis (CAH) in liver allografts during the first year posttransplantation; hepatitis was first observed between 6 and 25 weeks posttransplantation. HCV viremia was measured for all patients before transplantation and on posttransplantation days 3, 7, and 14, and months 1, 6, 12, and 24 to 41, by quantitative competitive RNA polymerase chain reaction (QC-PCR). HCV RNA levels on posttransplantation days 3, 7, and 14 were significantly higher among patients who subsequently developed CAH versus those who did not (P < .02 by t-test and Mann-Whitney test on all three dates). However, HCV RNA levels in sera obtained at 1, 6, and 12 months posttransplantation did not correlate with CAH at 1 year or with HCV genotype determined in posttransplantation sera. At least two serial liver biopsy specimens from each patient were stained for HCV nonstructural 4 (NS4) antigen by immunohistochemistry. The intensity of cytoplasmic staining of NS4 antigen was significantly higher for specimens with CAH versus those without CAH (P = .028 by chi 2). Three patients developed bridging fibrosis in liver allografts during the first year after transplantation; all three patients had intense (3+) immunostaining for NS4 antigen, and the infecting genotypes were 1a, 1b, and 1a plus 1b, respectively. In summary, the 18 patients all developed high-titer viremia by 1 month after liver transplantation, whereas CAH developed in 50% of allografts during the first year after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Serial density analysis of hepatitis C virus particle populations in chronic hepatitis C patients treated with interferon-alpha

In interferon treatment of chronic hepatitis C patients, the biochemical and virological responses mostly parallel each other. However, some patients who show persistent ALT normalization display continued viremia after cessation of therapy. High-density hepatitis C virus (HCV) particles, which are immune complex forms, are reported to be less infectious both in vitro and in vivo. To assess whether high-density HCV contributes to the response discrepancies and to clarify the association with patient outcome, sera were examined from chronic hepatitis C patients who were treated with interferon-alpha. This study included 10 sustained responders with viremia (SR + ve), 5 SR without viremia, 3 transient responders (TR), and 3 nonresponders (NR). The SR + ve patients were defined as those with continued ALT normalization and serum HCV-RNA positivity at 24 weeks after therapy completion. Serum samples obtained before and 24 weeks after therapy were ultracentrifuged on 35% sucrose. The ratio between high-density and low-density HCV was determined by quantification of HCV-RNA titers in the bottom and top fractions by competitive reverse transcription and by the polymerase chain reaction, and expressed as the bottom/top (B/T) ratio. The B/T ratios before therapy were 1:1 in all groups of patients, and 1:1 after therapy in TR and NR groups. Five out of 6 SR + ve patients who showed 1:1 ratio after therapy relapsed within 1 year. In contrast, all SR + ve patients whose ratios were 10-100:1 continued to show ALT normalization. These findings demonstrate that patients who have high-density HCV dominance after therapy show persistent ALT normalization despite viremia, which can be explained by predominance of the neutralized immune complex.

Randomized controlled trial of recombinant interferon-alpha 2b in the treatment of Chinese patients with chronic hepatitis C

To evaluate the efficacy of recombinant interferon (IFN) alpha 2b in the treatment of Chinese patients with chronic hepatitis C, a randomized controlled trial was conducted in 50 chronic hepatitis C patients: 25 patients received 3 million units of subcutaneously injected recombinant IFN-alpha 2b three times per week for 6 months, and 25 patients received no specific treatment were used as controls. At the end of the IFN treatment, 19 patients (76%) in the IFN-treated group normalized serum ALT compared with only 6 patients (24%) in the control group (p < 0.01). Relapse within 6 months after the completion of treatment occurred in 13 IFN-treated patients (68%). Normalized serum ALT was seen in 6 patients (24%) in the IFN-treated group and 1 patient (4%) in the control group 6 months after discontinuation of IFN therapy (p = 0.10). The presence of serum hepatitis C virus (HCV) RNA measured by reverse transcription-polymerase chain reaction was detected at the end of the IFN treatment in all 13 patients who relapsed after cessation of therapy. In only 3 of 25 IFN-treated patients (12%) was the presence of serum HCV RNA not detectable at the end of the IFN treatment or 6 months after cessation of therapy. No patient in the control group had undetectable serum HCV RNA during the study period. Using multivariate logistic regression analysis, the low pretreatment levels of HCV RNA, measured by a quantitative branched DNA amplification assay, was the only independent predictor of a sustained response to IFN therapy (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Viral load in samples from hepatitis C virus (HCV)-infected patients with various clinical conditions

Molecular methods for the absolute quantitation of nucleic acids present in biological samples have recently been developed and applied in basic and in medical virology; these studies indicated that competitive polymerase chain reaction (PCR) and competitive reverse transcription PCR (cRT-PCR)-based methodologies are currently the methods of choice for quantifying DNA and RNA species present in clinical samples at low concentration. Recently, quantitative molecular techniques were developed to study the hepatitis C virus (HCV) pathogenic potential, the natural history of HCV-infected patients and the efficiency of antiviral therapies in real time. The pilot study reported here was carried out using a cRT-PCR application for the direct quantitation of HCV RNA molecules in plasma samples of infected individuals which was recently developed in our laboratory. Although sharp individual variability of viral load was documented in this study, the mean HCV RNA copy number detected in samples from untreated HCV-infected patients with various clinical conditions (chronic active hepatitis, cirrhosis, cryoglobulinaemia and chronic hepatitis) was substantially similar, with only one exception: in samples from patients tested positive for anti-liver-kidney microsomal (anti LKM1) auto-antibodies, a significantly lower HCV viraemia level was revealed. Additionally, HCV viraemia was monitored in four patients with sustained biochemical and histological response (at least 12 months) following interferon-alpha discontinuation.

Comparison of full-length sequences of interferon-sensitive and resistant hepatitis C virus 1b. Sensitivity to interferon is conferred by amino acid substitutions in the NS5A region

We have previously demonstrated that sensitivity to interferon is different among hepatitis C virus (HCV) quasispecies simultaneously detected in same individuals and that interferon-resistant HCV quasispecies are selected during the treatment. To determine the genetic basis of their resistance to interferon, HCV genotype-1b was obtained from serum of three patients before and during interferon therapy, and their full-length nucleotide and deduced amino acid sequences were determined. Comparison of the pairs of interferon-resistant and interferon-sensitive HCV isolates in respective individuals demonstrated clusters of amino acid differences in the COOH-terminal half of the NS5A region (codon 2154-2383), which contained a common unique amino acid difference at codon 2218. Additional sequence data of the COOH-terminal half of the NS5A region obtained from six interferon-resistant and nine interferon-sensitive HCV confirmed the exclusive existence of missense mutations in a 40 amino acid stretch of the NS5A region around codon 2218 (from codon 2209 to 2248) in interferon-sensitive HCV. On the other hand, this region of interferon-resistant HCV was identical to that of prototype HCV genotype-1b (HCV-J, HCV-JTa, or HC-J4). We designated this region as the interferon sensitivity determining region. Thus, HCV genotype-1b with the prototype interferon sensitivity determining region appears to be interferon-resistant strains. The specific nature of these mutations might make it possible to predict prognostic effects of interferon treatment.

Hepatitis C virus genotypes in Singapore and Indonesia

5' untranslated and partial core (C) region sequence of hepatitis C virus (HCV) in 21 Singaporean and 15 Indonesian isolates were amplified by reverse-transcription polymerase chain reaction and sequenced with the use of conserved primer sequences deduced from HCV genomes identified in other geographical regions. The HCV genotypes are predominantly that of Simmonds type 1 and less of type 2 and 3 with the latter genotype currently not detected in Indonesia. The 5' untranslated sequences are related to HCV-1. DK-7 (Denmark), US-11 (United States of America), HCV-J4, SA-10 (South Africa), T-3 (Taiwan), HCV-J6, HCV-J8, Eb-1 and Eb-8. When compared with the prototype HCV-1, insertions are found within the 5' untranslated region of Singaporean isolates and not in the Indonesians. There are Singaporean and Indonesian isolates that have sequences within the 5' untranslated region that differ slightly from each other. Microheterogeneity is observed in the core region of two Singaporeans and one Indonesian isolate. Finally, not all HCV isolates can be amplified with the conserved core sequence primers when compared with the ease with which these isolates can be amplified with 5' untranslated region conserved primers.

Comparative study of two high doses of lymphoblastoid interferon in the treatment of chronic hepatitis C: influence on the levels of ALT, viraemia and histologic activity

Ninety consecutive patients with chronic hepatitis C were included in a randomized, uncontrolled trial to compare the efficacy of two treatment regimens, 10 MU (group A) vs 5 MU (group B), of lymphoblastoid interferon, in a step-down schedule for 24 weeks. All of the patients had antibodies against the hepatitis C virus, and all but one were HCV RNA positive in serum. The origin of the infection was attributed to blood transfusion in 30 patients and classified as sporadic in 60 patients. During treatment reduction in the ALT levels as well as the elimination of viraemia was observed in both treated groups, although these changes did not correlate significantly with the interferon dose. Nine months after the end of therapy, a sustained response was achieved in 13.6% (12/88) of the patients. Relapse in group B (87.5%) was significantly higher than in group A (59.1%). The percentage of cases which remained with undetectable HCV RNA was significantly higher for the sustained responders (66.7%) than for the non-responders (11.8%) and relapser patients (2.4%). Repeated liver biopsies showed an overall significant reduction of all the subindices of histological activity from patients with sustained response, except for fibrosis. In short: the 10 MU dosing regimen of lymphoblastoid interferon was as efficient as the 5 MU dose as it brought about a similar improvement in ALT levels, histological activity and elimination of viraemia, albeit 10 MU proved significantly more effective in the prevention of a relapse among the responders after 24 weeks therapy.

Hepatitis C and liver transplantation

Hepatitis C virus (HCV) is important to the liver transplant recipient for several reasons. First, chronic HCV infection is a frequent cause of end-stage liver disease in North America and Europe, where the majority of liver transplants are performed. Second, recurrence of HCV after liver transplantation is almost universal so that many liver transplant recipients with and without overt hepatitis are viraemic. Third, HCV infection in the organ donor and/or in the blood transfused in the peri-transplant period make acquisition of HCV possible. Finally, liver transplantation for chronic HCV infection represents a major financial burden to the health-care system in the USA and worldwide. Histological hepatitis not due to HBV or cytomegalovirus (CMV) is present in 14-35% of allografts from patients undergoing liver transplantation, and the majority of this is due to HCV infection. HCV infection recurs post-transplant in almost all patients with pre-transplant infection. Proof that HCV does recur has been provided by the sequencing of the hypervariable domain of the E2/NS1 region. The magnitude of HCV infection is underestimated by using serological assays in this immunosuppressed population. Using the b-DNA assay, HCV-RNA levels have been shown to increase in patients with recurrent infection. The long-term consequences remain to be defined but post-transplantation HCV infection is generally much less devastating than post-transplantation HBV infection, and many patients have clinically silent disease. It is likely that a carrier state exists in immunosuppressed transplant recipients since high HCV-RNA levels occur in the absence of liver damage. In one study, 1, 2 and 3 year patient survival rates were shown to be comparable in patients with chronic active HCV infection and with cryptogenic cirrhosis (94, 89 and 87%, and 84, 84 and 73%, respectively). A more recent study from the University of Pittsburgh which compared the outcome of a larger number of HCV-infected patients (n = 237) with a large number of control patients with non-viral disease (n = 801), showed that indeed HCV infection does impact negatively on both patient and graft survival (1, 2 and 3 year patient survival in the study and control groups of 78, 68 and 66% and 84, 82 and 78%, respectively, P = 0.001). Undoubtedly with time, the full impact of recurrent HCV infection will become apparent, although short-term survival is sufficiently good to warrant continued transplantation of this group of patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Host and viral features in chronic HCV infection: relevance to interferon responsiveness

Host and viral variables interact in determining the course and responsiveness to therapy of any viral infection. Presence of cirrhosis, serum levels of hepatitis C virus (HCV) RNA and the genotype of infecting virus are considered predictive of response to interferon (IFN) in chronic HCV infection. We evaluated these parameters in relation to IFN therapy in a cohort of anti-HCV-positive subjects with chronic hepatitis or cirrhosis. HCV RNA was detected by polymerase chain reaction (PCR) and by the branched DNA assay (bDNA), to quantify viraemia. HCV typing was performed by reverse-hybridization line probe assay. HCV RNA was detected in almost all anti-HCV-positive subjects with liver disease, PCR being more sensitive than bDNA. Hepatitis C viraemia was lowest in cirrhosis. Low pretreatment viraemia selected for those patients with chronic hepatitis obtaining a high rate of sustained response to IFN. The role of HCV type was less clearcut, due to the high prevalence in our population of type 1 (especially subtype 1b, accounting for 80% of cases). A trend towards a better response of non-1b genotypes was confirmed. This may be related to higher HCV RNA levels in type 1b-infected subjects. Cirrhosis remains however, independently from virological features, the strongest predictor of non-response to IFN.

Occurrence of antibodies reactive with more than one variant of the putative envelope glycoprotein (gp70) hypervariable region 1 in viremic hepatitis C virus-infected patients

The hepatitis C virus (HCV) is a frequent cause of chronic liver disease. A mechanism proposed as being responsible for virus persistence is evasion of the host immune response through a high mutation rate in crucial regions of the viral genome. We have sequenced the hypervariable region 1 (HVR1) of the virus isolated from three serum samples, collected during 18 months of follow-up, from an asymptomatic HCV-infected patient. A synthetic peptide of 27 amino acids, corresponding to the HVR1 sequence found to be predominant in both the second and third samples, was used as the antigen for detection of antibodies by enzyme-linked immunosorbent assay (ELISA). We observed reactivity against this HVR1 sequence in the first serum sample before the appearance of the viral isolate in the bloodstream; the reactivity increased in the second and third samples while the cognate viral sequence became predominant. Moreover, our results show that antibodies from all three samples recognize a region mapping at the carboxyl-terminal part of the HVR1 and are cross-reactive with the HVR1 sequence previously found in the same patient. The presence of anti-HVR1 antibodies was investigated in a further 142 HCV patients: 121 viremic and 21 nonviremic. Two synthetic peptides were used, the first corresponding to the sequence derived from the patient described above and the second one synthesized according to the sequence of the HCV BK strain. A high frequency of positive reactions against both HVR1 variants was detected in the samples from the viremic individuals. Finally, antibodies cross-reactive with both variants were shown to be present by competitive ELISA in 6 of 10 viremic patients. The potential negative implications of this observation for the host are discussed.

Hepatitis C virus genotypes among blood donors and their recipients in Iceland determined by the polymerase chain reaction

Eight antibody-positive individuals were detected among 12,000 blood donations during the first year of screening blood donors for hepatitis C virus (HCV) antibodies in Iceland. All 8 were found to have a history of intravenous drug abuse. Six of these 8 individuals had previously donated blood to 27 patients who could be traced and examined for HCV infection. The great majority (23/27, 85%) of the recipients had demonstrable HCV antibodies. Furthermore, RNA analysis with the polymerase chain reaction showed that all patients with HCV antibodies had HCV RNA in their serum and in one hemodialysis patient without HCV antibodies viral RNA could be demonstrated. Genotyping of the HCV strains showed that the genotype of the donor was also identified in all but one of the infected recipients of his/her blood or blood products. This study, therefore, substantiates high infectivity of the HCV by blood or blood factor donation and shows that viremic HCV antibody-negative individuals exist.

Treatment of chronic hepatitis C with interferon-alpha: sustained absence of hepatitis C virus RNA from serum after four courses of therapy

A patient with chronic hepatitis type C, confirmed by the detection of hepatitis C virus RNA (HCV RNA) in the serum and by histological examination of the liver biopsy specimen, was treated with four courses of interferon-alpha (IFN-alpha). For the first three courses of IFN-alpha the patient's serum alanine aminotransferase (ALT) level normalized during the administration of IFN-alpha but rose again after its cessation; similarly, HCV RNA was absent from the serum by the end of each course of treatment but could be detected once again after treatment stopped. The fourth course of IFN-alpha therapy, however, produced a sustained normalization of the ALT level and sustained absence of HCV RNA from the serum for 20 months after the end of treatment. This case suggests that patients with the potential for an eventual complete response to IFN-alpha therapy may show a normalization of serum ALT levels during IFN-alpha administration and the absence of HCV RNA in the serum by the end of each course of treatment (even if that particular course of treatment does not produce a sustained response).

Molecular epidemiology of hepatitis C virus infection among intravenous drug users

BACKGROUND/AIMS

The clinico-pathological features of hepatitis C virus infection in intravenous drug users are different from those found in other hepatitis C virus-infected patients. Our aim was to test whether specific viral variants circulate within this particular patient population.

METHODS

We studied the distribution of hepatitis C virus genotypes in 90 drug addicts and 484 controls, according to the method described by Okamoto.

RESULTS

Hepatitis C virus type 1a and 3a infections were more frequent among intravenous drug users than in 125 age-matched controls (48.8% and 21.1% vs 17.6% and 11.2%), accounting for the majority of infections in intravenous drug users. Analysis of hepatitis C virus genotypes according to age showed that, in the general population, hepatitis C virus types 1a and 3a were more prevalent among patients younger than 40 years of age than in older individuals (17.6% and 11.2% vs 1.4% and 0.6%).

CONCLUSIONS

These findings suggest that hepatitis C virus types 1a and 3a were recently introduced in Italy, presumably via needle-sharing among intravenous drug users, and from this reservoir they are extending to the general population, particularly among younger subjects.

Interferon treatment of chronic hepatitis C in patients with hemophilia or von Willebrand's disease in Japan

Seven patients with chronic hepatitis C, six hemophiliacs and a patient with von Willebrand's disease, were treated with interferon-alpha (IFN-alpha). Either 9 MU of recombinant IFN-alpha 2a or 3 MU of lymphoblastoid alpha-IFN was administered daily for 2 weeks and then three times a week for 22 weeks. Liver histology, hepatitis C virus (HCV) genotypes, and HCV-RNA levels in sera were investigated in all of the patients before IFN therapy was instituted. Liver histology was classified by the European classification. HCV genotyping conformed to the so-called Okamoto's classification. HCV-RNA levels in sera were quantitated by competitive polymerase chain reaction, using mutant RNA. Liver histology, HCV genotype, and serum HCV-RNA level (copies/ml) in each patient were: patient 1, chronic persistent hepatitis, type II, 3 x 10(3) respectively; patient 2, chronic active hepatitis (CAH) 2a, type III, 6 x 10(4); patient 3, CAH2a, type IV, 2 x 10(5); patient 4, CAH2b, type I, 2 x 10(7); patient 5, CAH2b, type II, 8 x 10(4); patient 6, CAH2b, type III, 7 x 10(6); and patient 7, CAH2b, type IV, 1 x 10(7). Sustained elimination of HCV was achieved in patient 3 and temporary elimination was achieved in patients 1 and 2. The other patients showed persistent HCV-RNA positivity in sera both during and after IFN treatment. Poor responsiveness to IFN was observed in patients with relatively progressive liver histology and high levels of HCV viremia.

Low humoral responses to hepatitis C virus among pediatric renal transplant recipients

Immunosuppressed patients infected with hepatitis C virus (HCV) are known to have a low prevalence of antibodies to the virus. We examined 12 HCV-infected renal transplant recipients and 18 immunocompetent patients in terms of viral markers. The renal patients had a lower prevalence of anti-C100-3 antibodies and lower titers of anti-p22 than the immunocompetents. Low titers of the antibodies seemed to be characteristic of HCV, because titers of anti-mumps and anti-cytomegalovirus antibodies were the same or even increased. Quantitation of HCV RNA showed approximately 200-fold more copies of mean HCV RNA in the sera of the kidney patients than in the immunocompetents. This indicates that the low humoral responsiveness to HCV is not due to the lower concentration of the virus. Immunosuppressive conditions seemed to suppress anti-HCV production with greater magnitude than other viral antibodies.

Hepatocyte regeneration in chronic hepatitis C and interferon treatment: analysis of immunohistological identification of proliferating cell nuclear antigen (PCNA)

To evaluate the usefulness of proliferating cell nuclear antigen (PCNA) immunostaining in the assessment of the efficacy of interferon (IFN) therapy in chronic hepatitis C, we investigated the proliferative activity of hepatocytes in 67 patients with chronic hepatitis C, using this immunostaining method. The percentage of PCNA-positive hepatocytes was 2.4% in patients with chronic persistent hepatitis, 2.5% in those with chronic aggressive hepatitis 2A, and 3.9% in those with chronic aggressive hepatitis 2B. The PCNA count increased with the progression of the liver disease. Patients were classified as complete, partial, and non-responders to IFN; the percentage of PCNA-positive hepatocytes before IFN therapy was 1.6% in the complete responders, 3.9% in the partial responders, and 4.9% in the non-responders. There was a significant negative correlation between the percentage of PCNA-positive hepatocytes and the response to IFN treatment. Thirty-two of 53 cases (60.4%) in which the PCNA labeling index (LI) was less than 5.0 were complete responders compared with 13 of 14 cases (92.9%) in which the PCNA LI was higher than 5.0, representing partial responders or non-responders (P < 0.001). Most complete responders had a low PCNA LI, irrespective of HCV genotype. Our findings indicate that PCNA immunostaining is a simple and reliable index of cell proliferation in liver regeneration, and may be a useful predictor of the response to IFN treatment in chronic hepatitis C.

Hepatitis C virus infection and genotypes in Japanese hemophiliacs

Liver function and antibodies to hepatitis C virus and to human immunodeficiency virus-1 were examined in 195 Japanese patients with hemophilia. One hundred and seventy-three were positive for antibody to HCV and 61 for antibody to human immunodeficiency virus-1. In 63 patients, we examined HCV genotypes according to the double polymerase chain reaction method. Forty cases (63%) were infected with hepatitis C virus with a single genotype, including type 1a in five, type 1b in 21, type 2a in seven and type 2b in seven; 16 (25%) were infected with double genotypes, including types 1a + 1b in 14, types 1b + 2a in one and types 1b+2b in one; and four (6%) were infected with triple genotypes, including types 1a + 1b + 2b in two. Genotype could not be determined in three patients by this method. In the 191 nonhemophiliac patients with chronic hepatitis C, HCV genotyping was as follows: type 1a in 0, type 1b in 121, type 2a in 40 and type 2b in 10 of 171 cases (89.5%) with single infection and types 1b + 2a in five and types 2a + 2b in one of six (5.5%) with double infection. In the remaining 14 patients, genotype could not be determined. Frequent transfusion of domestic and/or imported coagulation factor concentrates probably caused the high incidence of HCV infection with rare or mixed genotypes in Japanese hemophiliacs.

Usefulness of simple assays for serum concentration of hepatitis C virus RNA and HCV genotype in predicting the response of patients with chronic hepatitis C to interferon alpha 2a therapy

The use of two new assays was evaluated for predicting the response to interferon (IFN) therapy in patients with chronic hepatitis C. The genotype of hepatitis C virus (HCV) was established by an enzyme-linked immunosorbent assay based on genotype-specific recombinant peptides of the NS4 region (genotyping ELISA). The concentration of HCV RNA was measured by a branched DNA assay (bDNA assay). Seventy-eight patients received the same regimen of IFN alpha 2a. Of the 74 patients assessed who completed the program, 38 (51.4%) were responders; i.e., their serum aminotransferase levels remained normal for 6 months or longer after stopping IFN, while 36 (48.6%) were nonresponders. The results of the HCV genotype determined by the genotyping ELISA and by the polymerase chain reaction (PCR) assay based on genotype-specific primers were similar. The serum concentrations of HCV RNA as measured by the bDNA assay and by the competitive PCR assay correlated closely and significantly (r = 0.82, P < 0.001). Multiple logistic regression analysis showed that the serum concentration of HCV RNA determined by the bDNA assay, the HCV genotype determined by the genotyping ELISA, and the histology activity index (HAI) of the liver were independently associated with IFN efficacy. By using these three variables in combination, a predictive rate of 82.4% was obtained. A lower level of HCV RNA, genotype 2 and a lower HAI score for liver histology were predictive of a favorable response to IFN. Thus, the genotyping ELSIA and the bDNA assay appear to be useful for clinical management of patients receiving IFN therapy.

Genotyping of hepatitis C virus in South Africa

The six major hepatitis C virus genotypes were investigated by using samples from 79 seropositive and PCR-positive blood donors from three different regions of South Africa as well as 9 patients with chronic renal failure, 19 with liver disease, and 23 with hemophilia. PCR products of the genome were typed by restriction fragment length polymorphic analysis by RsaI-HaeIII and MvaI-HinfI double digestion. Type 5 occurred in 40% of this population group; type 1 occurred in 33%; and types 2, 3, and 4 were found in 13.8, 7.7, and 2.3%, respectively.

Hepatitis C virus type I(1a) in northern China

Twenty-four patients with hepatitis C virus (HCV) antibody from the Chinese North Western province of Jilin were further analysed by the immunoblot assay-2 (RIBA-2), reverse transcription-polymerase chain reaction (RT-PCR) for serum HCV RNA detection, and direct sequence-genotyping. Good concordance was found between the original second generation HCV antibody ELISA, RIBA-2, and serum HCV RNA. The occurrence of genotype I (1a), a genotype not previously reported in China, is described in 5(20.8%) of 24 cases, in association with genotypes II(1b) and III(2a) which were found in 16(66.7%) and 3(12.5%) of 24 cases, respectively. Imported blood products were unlikely to be the source of infection with genotype I (1a) but could not be definitively ruled out.

Rapid genotyping of hepatitis C virus isolates by dideoxy fingerprinting

A number of distinct hepatitis C virus (HCV) types and subtypes have been identified by DNA sequencing of multiple genome regions. It has been postulated that these might also reflect phenotypic differences in the nature of HCV infection. Recent evidence suggests a relationship between HCV genotype and alpha-interferon response in patients with chronic hepatitis C. A simplified method of genotyping in comparison to direct DNA sequencing was investigated with the intention of providing a rapid, less labour-intensive method for routine genotyping. HCV RNA was extracted from serum by a modified guanidinium/acid-phenol extraction and peripheral blood lymphocytes using RNAzol B (Cinna-Biotecx). The RNA was reverse transcribed and a 287 bp segment of the 5' non-coding region (5' NCR) amplified using a nested-PCR reaction. PCR products were purified using Qiaquick spin columns. Products were directly sequenced by cycle sequencing. Dideoxy termination analysis was carried out by cyclic extension of a 33P-labelled primer by Tth polymerase with termination by dideoxy thiamine (ddT) or cytosine (ddC). Reaction products were analysed by electrophoresis on denaturing 7 M urea/6% acrylamide gels followed by autoradiography. Computer aided sequence analysis indicated that conserved 5' NCR sequence variation alone was sufficient to identify HCV types 1a, 1b, 2a, 2b, 3 and 4. Dideoxy fingerprinting improved greatly the efficiency of genotyping with an approximate four-fold increase in throughput. In addition, the results were very easily analysed although it was essential to run appropriate controls for each genotype. Reactions incorporating ddT distinguished types 1, 2a, 2b, 3 (provisionally 1a & 1b); a ddC reaction confirmed 1a and 1b typing.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C--associated glomerular disease in liver transplant recipients

Hepatitis C virus (HCV) infection may be associated with extrahepatic illness including renal disease. We investigated the clinical and virological characteristics of three patients who developed a mesangial proliferative and sclerosing glomerulopathy alone or in association with membranoproliferative glomerulonephritis after liver transplantation for end-stage liver disease secondary to HCV infection. Using polymerase chain reaction technology and the IgM RIBA assay, viral load, genotype and IgM antibody response to HCV in the setting of glomerulonephritis was evaluated. Within 1 year of transplantation, the patients showed decreased renal function, proteinuria and recurrent hepatitis C liver disease. Likewise, HCV viral load increased following transplantation, whereas the viral genotypes remained unchanged. Although the first patient presented with classic type II cryoglobulinemia in association with glomerulonephritis, the second patient developed an IgM directed specifically against the hepatitis C core antigen. The third patient developed a low-titered IgM directed against the hepatitis C core antigen with rheumatoid factor activity but without cryoglobulinemia. All of the patients show IgM in glomerular capillary walls by biopsy. One patient has shown a clinical response to interferon (IFN) alfa-2b therapy without evidence of hepatic allograft rejection. The second and third patients have not responded to IFN or developed hepatic rejection. This study suggests that HCV-associated glomerulonephritis may complicate liver transplantation in conjunction with the production of increased amounts of IgM of variable specificity. The posttransplant setting may provide a unique situation in which to investigate the specific requirements for the onset of renal disease.

High prevalence of hepatitis C virus among urban and rural population groups in Egypt

Hepatitis C is a major health problem for Egypt. The aim of this study was to determine the seroprevalence of antibodies to hepatitis C virus among different population groups living in urban and in two different rural areas (Suez Canal and North Sinai) of Egypt. Secondary objectives were to study the possible association between multiple blood transfusions, haemodialysis or Schistosomiasis and the seroprevalence of antibodies to hepatitis C. A seroprevalence of hepatitis C virus in the urban blood donor population of 14.5% was found, confirming other reports. In the two rural areas of the Suez Canal and the North Sinai the seroprevalence was 14.4% and 15.5% respectively, showing a comparable seroprevalence in these three different populations. The seroprevalence was 70.4% in haemodialysis patients, 7.7% in health care workers, and 75.6% in thalassaemic children, thus a seroprevalence among multitransfused or haemodialysed patients comparable to the one described in many other countries. Schistomiasis does not seem to play a role in the seroprevalence of this disease in Egypt.

Relationship of genotype to level of hepatitis C viraemia determined by competitive polymerase chain reaction

To compare the levels of hepatitis C virus (HCV) viraemia in carriers of the same genotype in various stages of chronic HCV infection, we quantified the amount of HCV RNA by competitive polymerase chain reaction and determined HCV genotype using type-specific primers. The study population included 255 patients with chronic HCV infection (asymptomatic 33, chronic hepatitis 141, liver cirrhosis 50, hepatocellular carcinoma 31). Of these 255, the prevalence of HCV RNA genotype II was 67.8%, genotype III, 17.3% and genotype IV, 14.9%; no genotype I was found. The level of HCV RNA (logarithmic transformed copy numbers per 50 microliters of serum) was significantly higher in subjects of genotype II than in those of genotypes III or IV (mean titre 5.8 +/- 1.0 vs. 5.1 +/- 1.2 and 4.8 +/- 1.1, P < 0.05, respectively). There was no significant difference in the level of HCV RNA between genotypes III and IV. Of 173 patients of genotype II, there were no significant differences between the level of HCV RNA and the stage of liver disease or in the level of HCV RNA by age. Of the 129 with genotype II with a history of blood transfusion, there was no significant difference between the level of HCV RNA of patients with and without a history of transfusion or between that of patients with a history of blood transfusion and the time elapsed since blood transfusion. The level of HCV viraemia depended on the genotype of HCV RNA and did not correlate to age or to the stage of liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular epidemiology of hepatitis C virus infection amongst intravenous drug users in rural communities

The prevalence of hepatitis C virus (HCV) infection amongst a group of intravenous drug users (IVDUs) resident in West Suffolk (East Anglia, England) was investigated and compared with the prevalence of infection with hepatitis B virus (HBV) and human immunodeficiency virus (HIV). In addition, both the level of HCV persistence, as defined by detection of viral RNA, and the HCV genotypes present in this population were determined. It was found that HCV antibodies were present in 59% of those tested; by comparison 22% had antibodies to HBV and 1% antibodies to HIV. HCV RNA was found in 44% of those with HCV antibody. HCV genotype 1 was the most prevalent within this population although both genotypes 2 and 3 were also represented.

Interferon therapy for patients more than 60 years of age with chronic hepatitis C

Nineteen patients aged > 60 years with chronic hepatitis C (CHC) received interferon (IFN) therapy and a complete response (CR) was achieved by five of them (26%). The incidence of CH with severe fibrosis in this elderly group was significantly higher than in another 52 patients with CHC who were < 60 years of age (the younger group; P < 0.05). There was no significant difference in the hepatitis C virus (HCV) genotype distribution between the elderly group and the younger group. However, the HCV-RNA titre was significantly higher in the elderly group than in the younger group (P < 0.05). There was no significant difference in the efficacy rate of IFN in the elderly and younger groups after standardization of the background factors. In the elderly group, the HCV-RNA titre was significantly lower in the patients achieving CR than in those with no response (P < 0.05). These data suggest that elderly patients with a low HCV-RNA titre can still respond well to IFN therapy.

Predictive factors in the response to interferon therapy in chronic hepatitis C

Factors predicting the efficacy of interferon therapy were statistically analyzed on 111 patients with chronic hepatitis C. Of the treated patients (total doses of interferon; 96-468 MU), 35 (31.5%) had a long-term remission. On multivariate analysis, hepatitis C virus genotype (p < 0.0001), histological diagnosis (p < 0.05), fibrosis score of histological activity index (p < 0.01) and source of infection (p < 0.05) were found useful for predicting the response to interferon therapy. Our findings suggest that the outcome of interferon therapy can be predicted to some degree from pretreatment data, and that a new therapeutic strategy is necessary for the group of patients who are predicted to be nonresponders.

Genotype distribution in Nagoya and new genotype (genotype 3a) in Japanese patients with hepatitis C virus

We evaluated hepatitis C virus (HCV) genotype distribution among Japanese patients in the city of Nagoya and the possible existence of any other genotype not determined by Okamoto's method. Eighty-five of 93 (91.4%) anti-HCV-positive patients had detectable HCV RNA. The genotype of the HCV isolate was determined in 84 of 85 (98.8%) of these HCV RNA-positive patients by Okamoto's method but determination was not possible in one (1.2%). Genotype 1b was detected in 58 of the 85 patients (68.2%), genotype 2a in 20 (23.5%), genotype 2b in 3 (3.5%), and genotype 1b + 2a in 3 (3.5%). In the remaining 1 patient in whom the genotype could not be determined, we determined the nucleotide sequence of the core region in HCV RNA extracted from this patient and evaluated it by molecular evolutionary analysis. This HCV isolate was then classified as genotype 3a. These results suggest that genotype 3a is rare among Japanese patients with HCV; thus, when classifying Japanese isolates, we should take more care because genotype 3a is not determined by current typing systems.

Classifying hepatitis C virus genotypes

Hepatitis C virus (HCV) is the major aetiological agent for blood-borne non-A, non-B hepatitis worldwide. Since its discovery in 1989, at least 28 HCV genotypes have been reported, which differ by > 20% in the nucleotide sequence of the entire genome (approximately 9500 nucleotides) or the sequence of the E1 gene (576 nucleotides). Different HCV genotypes have distinct geographical distributions, and may be associated with variations in viral replication and disease-inducing activity, as well as poor response to interferons in patients with chronic hepatitis C.

Influence of the genotypes of hepatitis C virus on the severity of recurrent liver disease after liver transplantation

BACKGROUND/AIMS

Several genotypes of hepatitis C virus (HCV) have been identified by phylogenetic analysis, but their clinical relevance remains elusive. Liver transplantation for HCV-related cirrhosis offers a unique opportunity for prospective studies of this issue.

METHODS

Sixty anti-HCV-positive liver recipients with precise virological and histological assessments were included. HCV genotype was determined with both type-specific capsid primers and a line probe genotyping assay.

RESULTS

HCV genotype 1b was the predominant type before transplantation (40 of 60 patients); after liver transplantation, acute and chronic active hepatitis developed more frequently in these patients than in patients infected by other genotypes (31 of 40 and 24 of 40 vs. 8 of 20 and 4 of 20 patients). Actuarial rates of acute hepatitis and chronic active hepatitis were 77% and 59%, respectively, 3 years after transplantation in patients infected by type 1b and 40% (P = 0.008) and 22% (P = 0.004) in those infected by other types. There was no statistical relation between the level of HCV viremia and HCV genotypes both before and after transplantation. In contrast, after transplantation, serum HCV RNA values were significantly increased in patients who developed hepatitis after transplantation.

CONCLUSIONS

This study provides direct evidence that HCV 1b is associated with more aggressive recurrent liver disease than other genotypes.

Pretreatment viral load and response to prolonged interferon-alpha course for chronic hepatitis C

BACKGROUND/AIMS

We investigated the clinical benefit of long-term interferon therapy in chronic hepatitis C in relation to the pretreatment viral load and genotypes.

METHODS

Chronic hepatitis C patients were randomly assigned to receive 28-week (n = 45) or 52-week (n = 43) courses of interferon-alpha. The responses were correlated with pretreatment viremic levels assessed by a branched DNA assay and genotypes.

RESULTS

After the 28-week interferon-alpha course, sustained aminotransferase normalization showed correlation with a lower initial viral load. The normalization was achieved by 78% (7/9) of the low viremic (branched DNA-negative) patients, but only 22% (8/36) of the highly viremic (branched DNA-positive) patients (p < 0.01). Treatment with the 52-week interferon-alpha course increased the incidence of a sustained response in highly viremic patients and led to a decrease in relapse after therapy withdrawal (p < 0.05). Thus, 75% (6/8) of the low viremic patients and 49% (17/35) of the highly viremic patients showed a sustained response. The data further showed that frequent sustained responses in patients with genotypes III and IV were associated with a low initial viral load.

CONCLUSIONS

These findings suggest that although the pretreatment viral load is an important virological factor for predicting responses to interferon in chronic hepatitis C, relapse in highly viremic patients may be prevented by long-term therapy.

Frequent detection of hepatitis C virus subtype 3a (HCV-3a) isolates in Thailand by PCR using subtype-specific primers

By means of a polymerase chain reaction (PCR) method using subtype-specific primers for hepatitis C virus (HCV) subtypes 1a, 1b, 2a, 2b and 3a, the prevalence of each subtype among HCV isolates in Chiang Mai, Thailand, was determined. HCV-3a appeared to be the most common subtype in blood donors, and was also frequently found in patients with liver disease. HCV-1b, but not HCV-2a or -2b, was also commonly found in this area, while a considerable percentage of the total HCV isolates still remained unclassifiable by the above methods. Serotype analysis of the HCV isolates using C14-1 and C14-2 recombinant peptides revealed that HCV-3a was likely to carry an antigenic determinant(s) different from those of the major types 1 (HCV-1a and -1b) and 2 (HCV-2a and -2b).

Density analysis of hepatitis C virus particle population in the circulation of infected hosts: implications for virus neutralization or persistence

Hepatitis C virus has a low buoyant density in sucrose, but high-density particles are often observed in hepatitis C virus infection. To investigate the characteristics of circulating hepatitis C virus particles and their association with liver disease progression, we examined sera from two histologically normal hepatitis C virus carriers, 20 chronic hepatitis patients and five acute hepatitis C patients. The supernatants obtained after immunoprecipitation with anti-immunoglobulins antibody were subjected to sucrose equilibrium centrifugation. HCV-RNA positive fractions separated after the treatments were further examined for immunoprecipitation with anti-core hepatitis C virus antibody. We separated hepatitis C virus particle populations according to the density difference on 35% sucrose with centrifugation. The proportions of high and low density particles in hepatitis C virus populations were determined by means of competitive reverse transcription and polymerase chain reaction. Circulating hepatitis C virus particles in chronically infected patients could be separated into two populations: those immunoglobulin-bound with high densities and -unbound with low densities. Patients with severe liver inflammation had high-density hepatitis C virus that did not precipitate with anti-immunoglobulins but with anti-core hepatitis C virus antibodies. Thus, hepatitis C virus particle populations consist of low-density virions and high-density immune complexes and/or nucleocapsids. Among the chronic hepatitis patients, the dominant population shifted from low-density to high-density particles with the progression of liver disease. In acute hepatitis patients, this density shift was observed with alanine aminotransferase normalizations. Therefore, the major hepatitis C virus populations change from virion to immune complex and/or nucleocapsid with the progression of liver disease or inflammation.

Interferon therapy in chronic hepatitis C virus: evidence of different outcome with respect to different viral strains

The aim of the study was to assess the role of different viral strains of hepatitis C virus (HCV) in determining the outcome of the alpha-interferon (IFN) therapy. Fifty-seven patients (34 from Italy and 23 from Japan) with HCV-positive liver disease were enrolled in the study. The NS4 region of HCV was amplified in sera by "nested" polymerase chain reaction (PCR) using a primer pair synthesized according to the sequence of JK-1. The NS4 region was positive in 14 (41%) Italian and in 13 (56%) Japanese patients. In positive patients the sequence of the NS4 region was also obtained. Subsequently, HCV genotype was determined in all patients by PCR amplification of the core region. All patients received recombinant alpha 2a-interferon (IFN), 6 million units 3 times a week for 1 month followed by 3 million units 3 times a week for 5 months. The patients were followed for 1 year after the end of treatment. At the end of the follow-up, 17 (30%) had sustained normal levels of serum alanine aminotransferase (ALT). The outcome of treatment was not correlated with race, age, sex, histology, and pretreatment ALT level, but was significantly (P < 0.00001) associated with the presence of both the NS4-JK-1 region and HCV type II. Among the 27 NS4-positive patients, only 1 patient (3.7%) achieved a complete response, whereas the remaining 26 patients (95.3%) either were non-responders or relapsed after IFN was discontinued.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiologic survey and genetic analysis of endemic hepatitis C virus infection in a Japanese town with a high prevalence of hepatitis B virus carriers

Mass screening for hepatitis C virus antibody was carried out in 875 inhabitants (313 men and 562 women) of a town in Japan with a high rate of hepatitis B virus infection. The overall rate of positivity for anti-HCV was 8.8% (6.4% in men and 10.1% in women). The rate of positivity for hepatitis B virus surface antigen was 11.2%. Five subjects (0.6%) were positive for both markers. HCV-RNA was detected in 65 (88.4%) of 77 individuals who were positive for anti-HCV and in 1 (1.5%) of 60 individuals negative for anti-HCV. The genotype of the HCV genome was determined by PCR analysis using type-specific primers in 60 individuals. HCV type 1b was detected in 51 subjects (85%), type 2a in 3 subjects (5%), and type 2b in 6 subjects (10%). None of the individuals was infected with more than one genotype. The nucleotide sequences of the partial nonstructural 5 region of HCV type 1b genotype obtained from 6 individuals showed at least 92.0% homology in the nucleotide sequence, and 94.8% homology in the amino acid sequence. Homology among these clones was greater than their homology with previously described type 1b sequences. The findings suggest that there was a specific local origin of HCV infection, although it was not possible to identify any single source of HCV infection. The results also indicate that presence of asymptomatic HCV carriers.

Frequent patient-to-patient transmission of hepatitis C virus in a haematology ward

Blood transfusion is a well-documented route of transmission of hepatitis C virus (HCV). However, a persisting high frequency of HCV infections was recorded in our haematology ward even after screening of blood donors had been introduced. We investigated the viral strains in 37 patients with haematological malignant diseases who had developed hepatitis C when treated in the ward during 1990-93. 17 of the patients acquired hepatitis C despite being transfused only with blood components screened by second-generation anti-HCV tests. The viral strains were characterised by PCR genotyping and nucleotide sequencing of the hypervariable region of the E2 gene. Five clusters of closely related or identical viruses were found involving 2, 3, 4, 6, and 15 patients, respectively. Blood components could be ruled out as the common source of infection because no donor had given blood to all patients sharing a specific strain, and even donors whose blood had been given to several patients were negative for HCV RNA. All patients in each cluster had been treated in the ward during overlapping periods. These findings suggest that despite strict hygienic control, HCV transmission occurred between patients treated in the same hospital setting, as has previously been reported in a smaller group of haemodialysis patients.

Nucleotide-specific PCR for molecular virus typing

Nucleotide sequence studies detected a double-point mutation in the genomic RNA segment 4 (nt 871 and 872) of the persistent variant C/AA-pi of influenza C/Ann Arbor/1/50 virus. The 3'-end-points of two distinct PCR primers were positioned exactly at this genome location and thereby adjusted the priming determinant complementary to the varied strain or to its wild-type counterpart. Consequently, positive RT-PCR products strictly referred to one of the two viruses examined, in both cases, using either virion or infected-cell RNA templates. Artificial virus mixtures could easily be distinguished by this method in a subsequent qualitative gel analysis. PCR annealing conditions and control reactions were optimized, for the monitoring of influenza virus isolates throughout multifold passages. Thus, sequence diversity in just two neighbouring nucleotides is sufficient to determine whether or not successful PCR amplification takes place, and this method can be used as a reliable means of virus strain differentiation.

Incidence of hepatocellular carcinoma in chronic hepatitis B and C: a prospective study of 251 patients

The incidence of hepatocellular carcinoma (HCC) was prospectively studied in 251 chronic hepatitis patients, and was compared between the 127 cases of hepatitis B and 124 cases of hepatitis C. All patients were diagnosed by needle biopsy on entering the study, and the cases consisted of chronic persistent hepatitis (CPH), chronic active hepatitis (CAH)2a, and CAH2b (cirrhosis was not included). Of the cases of chronic hepatitis B, 5 cases of HCC (3.9%) were detected; among the chronic hepatitis C cases, 13 cases (10.4%) were detected. Thus, although the mean follow-up periods were in the same range, the incidence of hepatocellular carcinoma was 2.7 times higher in hepatitis C than in hepatitis B (chi 2 = 3.116, P < .05). Using the Kaplan-Meier method, the incidence of HCC was significantly higher in chronic hepatitis C (P = .0194, generalized Wilcoxon test). In hepatitis C, the incubation period until HCC was detected was shorter when the liver disease was more advanced. Such a tendency was not observed in hepatitis B. In the 13 cases of HCC occurring in chronic hepatitis C, noncirrhotic liver was seen in only 1 case (7.7%), whereas 2 of the 5 cases of HCC (40%) in chronic hepatitis B were noncirrhotic. The prevalence of hepatitis C virus (HCV) genotypes II and III was the same in the total followed cases and HCC cases.

ELISA for anti-HCV antibody employing a shorter synthetic core region peptide

A new ELISA for anti-HCV antibody was developed employing a shorter synthetic N-terminal peptide, 2-62aa, within the core region of 1-191aa. The basic performance of the assay was comparable to three other second-generation assays using longer HCV core antigens. To evaluate assay performance at the borderline level, 25 samples with indeterminate results were selected from 3000 routine serum samples. Only 5 of the 25 sera were found to be HCV-RNA-positive by a nested PCR assay and with apparent clinical evidence of HCV infection. The results of the new ELISA agreed with those of the PCR-RNA test in 23/25 (kappa statistics 0.75), whereas C22-3 of the RIBA II test using 2-120aa of the core agreed in 9/25 (0.09), the Abbott pHCV-34 EIA test using 1-150aa agreed in 10/25 (-0.12), and a neutralization inhibition assay for Abbott EIA II using 2-120aa agreed in 6/25 (0.02). These results indicate that the UBI CORE ELISA has greatly improved specificity and can be a useful indication of viremia in HCV infection.

Chronic hepatitis C virus infections: predictive value of genotype and level of viraemia on disease progression and response to interferon alpha

The effects of hepatitis C virus genotype and viraemia on disease outcome in patients with chronic hepatitis C virus infection were studied. Patients infected with genotype 1 tended to develop more severe disease, and to respond less well to interferon (IFN) treatment, but no pretreatment variable successfully predicted either the severity of the disease or the response to IFN. Failure to eliminate the virus during the first three months of therapy, however, predicted a failure to derive long term benefit from the current IFN regime. Hence pretreatment variables cannot be used to determine whether individual patients will respond to IFN, but observations during the first three months of therapy can be used to decide which patients will not respond to prolonged therapy. In these patients consideration should be given to changing the IFN dosing regime or using alternative treatments.

High prevalence of a rare hepatitis C virus in patients treated in the same hemodialysis unit: evidence for nosocomial transmission of HCV

Hepatitis C virus (HCV) is a major cause of hepatitis among patients treated with maintenance hemodialysis. Blood transfusion appears to be the primary risk factor, but nosocomial transmission of HCV in the dialytic environment has been hypothesized. We addressed this issue by analyzing the individual variation of genomic sequences of HCV in 28 patients on chronic hemodialysis (HD) from the same department and 25 environmentally unrelated patients with HCV-related liver disease. Genome variations of HCV were studied by single strand conformation polymorphism (SSCP) analysis of polymerase chain reaction products obtained from the 5'-untranslated region of the viral genome and by sequence analysis. Six different SSCP patterns were identified in HD patients versus 16 in control patients. Among HD patients the three more frequent SSCP patterns accounted for 85% of observations, while in the control group each pattern was found in 4 to 12% of patients. The ability of SSCP to discriminate sequence variation was proven by sequence analysis which confirmed identity/diversity of sequences selected by SSCP. Moreover, sequence analysis permitted a recognition of the most frequent genome observed in HD patients as a type 4 HCV, which is considered to be rare in the Italian population. The relative homogeneity of HCV variants in HD patients treated in the same HD and the high prevalence in this unit of a rare viral variant support the possibility of a nosocomial transmission of HCV in the dialytic environment.