Severity of liver disease with different hepatitis C viral clones

A clinicopathologic study of chronic non-A, non-B (type C) hepatitis in Taiwan: comparison between posttransfusion and sporadic patients

To elucidate the clinicopathological course and the role of hepatitis C virus in posttransfusion and sporadic chronic non-A, non-B hepatitis in Taiwan, we retrospectively studied 85 histologically confirmed patients with long-term follow up. Antibodies against hepatitis C virus (anti-HCV) by a second-generation assay were positive in 81% of the patients: 88% in the posttransfusion group and 76% in the sporadic group. Clinical manifestations were generally mild, and were noted in only half of the patients. During follow up, 33% (28 of 85 patients) had episodes of acute exacerbation of chronic liver disease and 24% (20 of 85) had normalized liver tests. Patients with normalized liver tests were usually anti-HCV negative (55% vs. 8%, p < 0.001). In 34 patients who had had blood transfusions, initial liver biopsies revealed chronic active hepatitis in 41%, active cirrhosis in 6%, and inactive cirrhosis in 9%. Follow-up biopsies in eight patients in this group showed histological progression in three after an average of 40.6 months. In the 51 sporadically infected patients, initial work-up revealed chronic active hepatitis in 37%, active cirrhosis in 4%, and inactive cirrhosis in 14%. Among the nine who underwent repeated biopsies, only one (11%) had progression. Patients above age 40 displayed more severe histologic activity than those below 40 (p < 0.005). Three patients, all with cirrhosis, died of hepatocellular carcinoma 7 to 12 years after follow up. Further genotyping study of hepatitis C virus in 28 patients showed that type II virus was most predominant in Taiwan and histologic severity was similar among patients infected with different genotypes.(ABSTRACT TRUNCATED AT 250 WORDS)

Genotyping of Canadian hepatitis C virus isolates by PCR

We used PCR for hepatitis C virus (HCV) genotyping with type-specific primers from the core and NS5 genes. Type I was predominant in the general population (58% in blood donors) as well as in different risk groups, such as intravenous drug abusers (58%), blood transfusion recipients (64%), hemophiliacs (62%), and patients with HCV chronic liver disease (76%). Types II, III, and IV were less prevalent in Canada, being found in 10.92, 6.72, and 5.88% of the population, respectively. The type II core primer was not type specific and reacted with the majority of our type I HCV samples, suggesting a false-positive dual infection with two different genotypes (I and II). Digestion of these amplified type I and type II products with restriction endonuclease AccI proved to be very useful in the exclusion of false-positive dual type I and type II infections.

Hepatitis C virus chronic infection as a common cause of mixed cryoglobulinaemia and autoimmune liver disease

OBJECTIVES

Mixed cryoglobulinaemia (MC) and autoimmune chronic hepatitis (AI-CH) are frequently associated with hepatitis C virus (HCV) chronic infection. Because HCV represents a possible common aetiological factor, the aim of the present study is to investigate the clinico-serological alterations of both MC and AI-CH and to verify a possible overlap between these disorders.

SETTING

Patients from three tertiary referral centres.

SUBJECTS

Two Italian series of 88 MC patients and 30 AI-CH type 1 were studied.

RESULTS

MC and AI-CH share several clinico-serological features. The patients' mean age (MC vs. AI-CH: 60 +/- 9 vs. 57 +/- 13 years), disease duration (10.5 +/- 5 vs. 9.6 +/- 6 years), and female/male ratio (3.4 vs. 3.3) were very similar in the two series. Typical hallmarks of MC, i.e. purpura, arthralgias, and weakness, circulating mixed cryoglobulins with rheumatoid factor activity, and hypocomplementemia were also recorded in a significant number of AI-CH patients. Similarly, chronic active hepatitis was found in 68% of MC patients and its histological and serological alterations were comparable with those of AI-CH; moreover, amongst various autoantibodies, antinuclear antibodies and/or anti-smooth-muscle antibodies were detected in half of the cases of MC. Anti-HCV antibodies, detected by second-generation Chiron ELISA and RIBA, were present in a high percentage of both MC and AI-CH (94 vs. 80%), and frequently associated with HCV viraemia (86 vs. 77%). Finally, anti-GOR, the HCV-related autoantibodies, were found in half cases of MC and AI-CH.

CONCLUSIONS

On the whole, these data suggest that HCV in combination with other infectious and environmental and genetic factors can trigger a complex immunological disorder with different clinical patterns.

Analysis of hepatitis C virus genotypes by a line probe assay and correlation with antibody profiles

The 5' untranslated regions derived from 54 patients with a chronic hepatitis C virus infection were analyzed to determine the (sub)type of hepatitis C virus. Labelled polymerase chain reaction products from 5' untranslated region were used as probes for reverse hybridization in a line probe assay (Inno-LiPA) and results were validated by comparison with direct sequencing data. Five different genotypes could be distinguished based on 5' untranslated region sequence diversity. Results of typing by line probe assay and direct sequencing were similar. Antibody responses against core, NS-3, NS-4 and NS-5 epitopes were detected by RIBA-4 and Inno-LIA HCVAb II confirmatory assays. There was no consistent correlation between genotype and anti-HCV responses, although types 2, 3 and 4 hepatitis C virus isolates show poor reactivity with NS-4 ep!%"pes.

Hepatitis C virus genotypes, reactivity to recombinant immunoblot assay 2 antigens and liver disease

To clarify the relationship between hepatitis C virus (HCV) genotypes and liver disease, we typed HCV genomes in the sera of 151 blood donors, 180 patients with type C chronic liver disease (CLD), and 30 haemophiliacs residing in Hiroshima, Japan. All of the subjects were positive for anti-HCV and HCV-RNA, and were examined for seroreactivity to HCV-specific antigens. The HCV genotypes were determined by polymerase chain reaction (PCR) with type-specific primers deduced from the putative core region of the HCV genome. Significantly more (P < 0.001) type III HCV was found in the samples from the CLD patients (80%) than in those from the blood donors (55%). Significantly more (P < 0.001) type III HCV was found in the samples from the blood donors (29.1%) than in those from the CLD patients (11.7%). There was no significant difference in the distribution of the HCV types among the patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma. A four-antigen recombinant immunoblot assay (RIBA-2) assay was used to compare the serum samples for their reactivity to a range of structural and nonstructural peptides specific for HCV (5-1-1, C100-3, C33c, and C22-3). The frequency of seropositivity to 5-1-1 and C100-3 was significantly higher (P < 0.001) in type II HCV-infected blood donors than in type III HCV-infected donors (68.2% and 65.9% vs. 4.5% and 22.7%, respectively). Among the type III HCV-infected individuals, the CLD patients had a significantly higher (P < 0.01) frequency of seropositivity to 5-1-1 than the blood donors (33.3% vs. 4.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus: historical perspective and current concepts

Over the past 30 years, hepatitis C has emerged from shadowy enigma to important public health problem. The existence of the etiological agent of this disease was first appreciated two decades ago but significant progress in its understanding had to await its molecular characterization within the past 5 years. The virus is a member of the family Flaviviridae and is the cause of approximately 20% of clinical viral hepatitis in the United States. While the control of the transmission of hepatitis C virus in blood and blood products has been nothing less than spectacular, the control of community-acquired hepatitis C will be a major challenge to the scientific and medical communities.

Hepatitis C virus genotypes in France: comparison of clinical features of patients infected with HCV type I and type II

Two major hepatitis C virus genotypes, F1 and F2, corresponding to hepatitis C virus type I and type II respectively, were found in France. To investigate the correlation between infection with these genotypes (F1 and F2) and clinical features of patients, serum samples proven to be hepatitis C virus positive by polymerase chain reaction amplification on 5' non-coding region were further amplified in the NS3 region with nested polymerase chain reaction. The NS3-polymerase chain reaction products were Southern blotted and hybridized with specific probes to identify the genotype of hepatitis C virus. Of 70 samples 64 were NS3-polymerase chain reaction positive. Twenty-eight (40%) samples were hepatitis C virus type I (F1) and 34 (49%) were hepatitis C virus type II (F2), while one sample (HB) hybridized with both probes and another (HN) hybridized with neither. Some samples were sequenced, with results consistent with those of hybridization. The HB sample was related more to hepatitis C virus type II than to type I and the HN sample was divergent from both type I and type II genotypes. Clinical profiles of patients infected with hepatitis C virus type I and type II were compared. Type I infected patients were younger (p < 0.01) and more often male (p < 0.05) than those of the type II group. Nine of 28 patients in the type I infected group had a history of drug abuse, whereas none did in the type II group. Five of 22 (23%) type I infected patients and 19 of 32 (59%) type II infected patients had cirrhosis (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Typing of hepatitis C virus isolates by DNA enzyme immunoassay

Recently, at least six types of hepatitis C viruses (HCV) have been identified. Different types of HCV appear to possess different pathogenic properties and a different sensitivity to interferon treatment. Typing of HCV isolates may therefore be an important diagnostic procedure. We report on a new method for identification of HCV types 1a, 1b, 2a, 2b and 3a which are most prevalent in Europe, North America and Japan. The assay is based on a combination of two well established techniques, the polymerase chain reaction (PCR) and DNA enzyme immunoassay (DEIA). In the first step of the method a cDNA of about 250 bp corresponding to the HCV core-region is amplified by nested PCR. The target cDNA is then hybridized to type-specific oligonucleotides fixed to a solid phase through an avidin-biotin bridge. The formed hybrids are detected by a standard ELISA using monoclonal antibodies reacting with double-stranded DNA. Typically, signal-to-noise (S/N) ratios between 18.2 and 48.6 could be observed when different HCV types/subtypes were analyzed by this method. The test was evaluated using cloned HCV cDNAs of known types and by sequence determination of some of the typed cDNAs. Typing of 115 isolates from Germany, Russia and Turkey revealed that subtype 1b (59-100%) and 1a (24-32%) are most prevalent in these countries.

Contribution of hepatitis C virus to non-A, non-B fulminant hepatitis in Japan

To assess the contribution of hepatitis C virus to non-A, non-B fulminant hepatitis in Japan, we compared 10 major clinical features among 7 patients with type B fulminant hepatitis (type B group), 13 patients with non-A, non-B fulminant hepatitis with evidence of hepatitis C virus infection (type C group) and 10 patients without evidence of hepatitis C virus infection (NANB group). Duration from first symptom to coma and that from onset of jaundice to coma was significantly longer in the type C group (median = 39 and 25 days, respectively) and in the non-A, non-B group (median = 29 and 12 days, respectively) than in the type B group (median = 9 and 2 days, respectively) (p < 0.01). The maximum median AST level was significantly lower in the type C (1,689 U/L) and non-A, non-B groups (1,353 U/L) than in the type B group (5,780 U/L) (p < 0.05). Serum transaminase levels showed a single peak in six of seven of the type B patients, whereas they formed two or more peaks in all of the type C patients and in most of the non-A, non-B group (p < 0.05). Six of seven in the type B group, 6 of 13 in the type C group and 4 of 10 in the non-A, non-B group survived (p < 0.05). We found no significant difference in any of the 10 clinical features between the type C and non-A, non-B groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Genotypes of hepatitis C virus in Guangxi province, southern China

Hepatitis C virus (HCV) has been subdivided into at least four genotypes, and the prevalence of each genotype has been reported to differ widely in different countries. Of 304 patients with chronic liver diseases (68 with chronic hepatitis, 50 with liver cirrhosis and 186 with hepatocellular carcinoma) from Guangxi Province in southern China, only 9 (3.0%) had antibodies to HCV as determined by a second-generation enzyme immunoassay with a cut-off index of 2.0 or more. The HCV genotypes of these nine cases were examined using polymerase chain reaction with type-specific primers deduced from putative core gene. Seven of the nine cases had type II infection and the other two cases showed double infection with types II and IV. These findings indicate that the predominant HCV genotype in the Guangxi area is type II, as is the case in Japan, although the prevalence of HCV infection in patients with chronic liver diseases is much lower.

Sequence analysis of the 5' untranslated region in isolates of at least four genotypes of hepatitis C virus in The Netherlands

The RNAs of hepatitis C virus (HCV) isolates from 62 patients with chronic HCV infection were analyzed by direct sequencing of the 5' untranslated region. Two important sequence motifs were recognized: one between positions -170 and -155 and the other between positions -132 and -117. These motifs are partly complementary. All three previously published genotypes were observed; 34 (55%) isolates were classified as type 1 (including prototype [from the United States] and HCV-BK [from Japan] sequences), 11 (18%) were classified as type 2 (including HC-J6 and HC-J8), and 12 (19%) were classified as type 3 (including EB1); one patient was infected with genotypes 1 and 2. Four (6%) isolates showed aberrant sequences and were therefore provisionally classified as genotype 4. These results indicate the significance of sequence variation among the 5' untranslated regions of different HCV genotypes and indicate that this region could possibly be used for consistent genotyping of HCV isolates.

Hepatitis C virus genotypes are not responsible for development of serious liver disease

Although hepatitis C virus (HCV) is known to have at least four kinds of genotypes, no clear relationship has yet been established between the genotype and the severity of liver disease. Therefore, we determined HCV genotypes in sera of 251 Japanese patients with type C chronic liver disease, using polymerase chain reactions with six independent primers. One set of primers and a probe derived from 5'-noncoding region of HC-J1 was supposed to detect all four genotypes, while the other five were devised to detect each of the genotypes. Among the patients, the major genotype was type II (69%) and the second most common was type III (18%). Type IV was found in 7%, while none had type I genotype. There was no significant difference in the distribution of any genotype among different stages of liver disease, although the ratio of type II to type III tended to be higher in the group of cirrhosis and hepatocellular carcinoma than in the chronic hepatitis group (5.5 vs 3.0). The amounts of HCV RNA were significantly greater in patients with type II (P < 0.001) compared with those with types III and IV. However, HCV concentrations of each genotype were not associated with the disease status. These results suggest that HCV genotypes are unlikely to be responsible for the development of more serious liver disease.

Hepatitis C virus and liver diseases

Hepatitis C virus (HCV) was identified molecularly and a procedure for its diagnosis was developed. In Japan, 70-80% of all cases of chronic liver disease, including hepatocellular carcinoma, are associated with HCV infection. Hepatitis C virus is a typical RNA virus with a high mutation rate. At least six variants of HCV have been identified by their nucleotide sequences. These variants are still classified into three types each containing at least two subtypes; that is, 1a (type I) and 1b (type II), 2a (type III) and 2b (type IV), and 3a (type V) and 3b (type VI). Type 1b (type II) is the predominant HCV in Japan. Even HCV cDNA clones isolated from a single patient showed mutations of HCV, especially in envelope-coding regions. Thus HCV may change during the course of chronic hepatitis due to the high mutation rate of HCV itself and elimination of some clones by immune reactions or interferon therapy. These findings explain the higher rate of chronic HCV infection and indicate that production of an effective vaccine is difficult.

Hepatitis C virus after interferon treatment has the variation in the hypervariable region of envelope 2 gene

There is a hypervariable region in the envelope 2 gene of the hepatitis C virus genome, whose heterogeneity in different hepatitis C virus isolates has been suggested to be a result of the immune selection of escape variants. To determine the role of hypervariable region variants in the mechanism of resistance to interferon observed in 75-80% of interferon-treated patients with chronic hepatitis C, hypervariable region sequences were compared before and after interferon treatment. Eight patients with chronic hepatitis C were treated with recombinant interferon-alpha-2b. DNA containing the hypervariable region was obtained by reverse transcription-polymerase chain reaction from serial plasma samples of each patient and directly sequenced without cloning to determine changes in the predominant sequence. In two patients, hepatitis C virus-RNA was eliminated by interferon treatment. In the remaining six patients, hepatitis C virus-RNA was not eradicated. The predominant hepatitis C virus which survived interferon treatment was the mutant hepatitis C virus with 3-19 out of 81 nucleotide substitutions in the hypervariable region, resulting in 2-14 out of 27 amino acid changes. Most of the nucleotide substitutions were nonsynonymous, indicating that there were positive selections for amino acid changes in the hypervariable region. The change rate was significantly higher in patients whose plasma hepatitis C virus-RNA was consistently detectable during and after interferon treatment than in patients whose plasma hepatitis C virus-RNA became undetectable during treatment and reappeared after the cessation of the treatment (4.23 +/- 0.43 vs 0.77 +/- 0.20 x 10(-1)/site/year, p < 0.01). This suggests that the evolution of the hypervariable region was associated with the effect of interferon treatment. These results suggest that hypervariable region variants play an important role in maintaining persistent infection during interferon treatment by evading host immune surveillance.

Identification of hepatitis C virus subtype 3b (HCV-3b) among Japanese patients with liver diseases using highly efficient primers for reverse transcription-polymerase chain reaction

With a reverse transcription-polymerase chain reaction method that utilized highly efficient primers, the NS5 region of hepatitis C virus (HCV) genome could be amplified from all of the 24 serum samples randomly obtained from Japanese patients with liver diseases. Subtype analysis on the basis of nucleotide sequence similarities of the amplified fragments revealed that 2 out of 24 Japanese patients (8.3%) were infected with the recently identified subtype HCV-3b, which had been thought to be rare in Japan.

Prospective study of alpha-fetoprotein in cirrhotic patients monitored for development of hepatocellular carcinoma

The usefulness of measurements of serum alpha-fetoprotein elevation for diagnosis of the development of hepatocellular carcinoma was evaluated by a prospective study of 260 patients with cirrhosis. Hepatocellular carcinoma was found in 55 patients during the 5-yr follow-up, excluding 7 found to have hepatocellular carcinoma in the first 6 mo. The cumulative incidence of hepatocellular carcinoma was 26% in the 185 patients who had alpha-fetoprotein levels below 20 ng/ml at the time of entry and 46% in the 68 patients who had alpha-fetoprotein levels of 20 ng/ml or more but below 200 ng/ml. In 169 of the patients, serum levels of alpha-fetoprotein were assayed regularly for at least 2 yr. The incidence of hepatocellular carcinoma development in the 36 patients who had repeated transient increases in alpha-fetoprotein to above 100 ng/ml was 36%. This was significantly higher than the incidence in the 99 patients who had alpha-fetoprotein levels consistently below 20 ng/ml. Thus patients who had alpha-fetoprotein levels of 20 ng/ml or more, who had transient increases in alpha-fetoprotein or who had both should be treated as being in a super-high-risk group for hepatocellular carcinoma. Frequent and careful examination by ultrasonography of such patients is recommended.

Rapid detection of hepatitis C virus RNA by direct capture from blood

A new diagnostic assay for hepatitis C virus RNA detection is described. HCV genomic RNA is captured onto streptavidin-coated magnetic beads by solution hybridization with biotinylated complementary oligonucleotides. The specificity of the capture assay is confirmed using different capture oligonucleotides as well as sera representing different types of HCV. Sensitivity was determined by testing serial dilutions of a HCV infected plasma. A panel of 50 sera was tested for anti-HCV by a Line Immunoassay and for HCV-RNA by both a conventional guanidinium extraction method and the new capture assay. The specificity of the capture assay was 95.8% and the sensitivity was 92.3% compared to the standard protocol. This method provides a rapid and simple alternative for HCV-RNA detection in blood samples.

Reduction of synonymous substitutions in the core protein gene of hepatitis C virus

Molecular evolutionary analyses were carried out to elucidate the phylogenetic relationships, the evolutionary rate, and the divergence times of hepatitis C viruses. Using the nucleotide sequences of the viruses isolated from various locations in the world, we constructed phylogenetic trees. The trees showed that strains isolated from a single location were not necessarily clustered as a group. This suggests that the viruses may be transferred with blood on a worldwide scale. We estimated the evolutionary rates at synonymous and nonsynonymous sites for all genes in the viral genome. We then found that the rate (1.35 x 10(-3) per site per year) at synonymous sites for the C gene was much smaller than those for the other genes (e.g., 6.29 x 10(-3) per site per year for the E gene). This indicates that a special type of functional constraint on synonymous substitutions may exist in the C gene. Because we found an open reading frame (ORF) with the C gene region, the possibility exists that synonymous substitutions for the C gene are constrained by the overlapping ORF whose reading frame is different from that of the C gene. Applying the evolutionary rates to the trees, we also suggest that major groups of hepatitis C viruses diverged from their common ancestor several hundred years ago.

Serological responses to different genotypes of hepatitis C virus in France

The relationship between hepatitis C virus (HCV) genotypes and antibody status was studied in 104 chronic non-A, non-B hepatitis patients and asymptomatic HCV-infected blood donors. On the basis of amplification of the nonstructural protein 3 (NS3) coding region by PCR and hybridization with specific probes, 55 and 42 patients were identified as being infected with type I and type II, respectively, according to the classification by H. Okamoto, K. Kurai, S. Okada, K. Yamamoto, H. Lizuka, T. Tanaka, S. Fukuda, F. Tsudaand, and S. Mishiro (Virology 188:331-341, 1992). All samples were tested for antibodies to 5.1.1, C-100, C-33, and C-22 proteins by a second-generation recombinant immunoblot assay. Among 97 patients with known HCV genotypes, 31 of 42 patients infected with type II and 24 of 55 infected with type I had antibodies against all four antigens (P < 0.01). In the type II-infected group, more patients had detectable antibodies to 5.11, C-33, and C-22 proteins than in the type I group (P < 0.05). No difference was found in the serological response to C-100 between the two groups.

Chronic hepatitis in haemophilia

Chronic hepatitis affects almost all haemophiliacs treated with non-virally inactivated clotting factor concentrates. The virus responsible is hepatitis C (HCV) and most patients have non-neutralising antibodies with circulating virus. Although the majority also have evidence of past infection with hepatitis B, less than 5% are chronic carriers of HBsAg. Chronic hepatitis C can be associated with severe and progressive liver disease but the development of complications is slow. Treatment with recombinant interferon alpha given subcutaneously normalises the liver function in 50% of patients, but 50% of responders relapse on stopping treatment. Liver transplantation is successful in patients with advanced liver disease and it offers the added advantage of phenotypic cure of the haemophilic state.

Changes of serum 2',5'-oligoadenylate synthetase activity during interferon treatment of chronic hepatitis C

It was our aim to evaluate whether the baseline activity of 2-5 oligoadenylate synthetase (2-5 OAS) in serum and changes induced by the treatment with interferon are relevant factors in remission of chronic hepatitis C. Seventeen out of 30 adult patients with chronic hepatitis C were randomized to receive recombinant alpha-2b interferon at the dosage of 3 MU three times weekly. By the end of the third month, nine patients had normalized transaminase levels and continued to receive 3 MU of interferon for an additional 3 months, whereas in eight non-responders the dosage was increased to 6 MU for the same period of time. A single patient responded to the increased dosage. Baseline 2-5 OAS serum activity was significantly higher in patients with chronic hepatitis when compared with normal controls. Follow-up on the 13 untreated cases showed that 2-5 OAS elevation was stable and unrelated to concomitant infections. Comparison of responders and non-responders showed that the latter had higher baseline 2-5 OAS activity, tended to have an earlier and higher peak in the enzyme during the first 4 weeks of treatment, and maintained higher levels during the first 3 months of therapy. The increased dosage of interferon in this group led to an additional, although temporary, increase in 2-5 OAS. Our data suggest that HCV infection by itself induces elevated 2-5 OAS levels. The paradoxical increase in non-responders indicates that monitoring of the enzyme in serum does not predict the response to interferon. The role of the 2-5 OAS pathway in inducing the antiviral state in HCV infection should be further evaluated at tissue level.

Superinfection of heterologous hepatitis C virus in a patient with chronic type C hepatitis

A Taiwanese woman who had chronic infection of type II hepatitis C virus was superinfected by type III hepatitis C virus after blood transfusion. The subtypes of the hepatitis C virus were determined by direct sequencing of the envelope region of the viral genome in serial serum samples before and after transfusion. The original virus in the patient had a 95.6% homology to the Taiwanese isolate (a type II virus) by comparing nucleotide sequences of the envelope region. After transfusion, markedly elevated serum aminotransferase activities were noted and the virus sequenced showed only a 55.2% homology to the Taiwanese isolate but had a 88.9% homology to a Japanese isolate (a type III virus). After recovery from the acute episode, the newly introduced type III virus became undetectable and type II virus predominated again but with significant genetic variation in the follow-up samples as compared with the original type II virus. It was concluded that superinfection of hepatitis C virus indeed occurs in humans, and this should be taken into consideration in the pathogenesis of reactivation of chronic type C hepatitis.

Prevalence, genotypes, and an isolate (HC-C2) of hepatitis C virus in Chinese patients with liver disease

China has not been extensively investigated for the prevalence of hepatitis C virus (HCV) infection among people with or without liver disease. We analyzed serum from 2,177 liver disease patients from 7 cities in different areas of China. Of 435 acute hepatitis patients, only 11% were positive for HCV RNA, while hepatitis B surface antigen (HBsAg) was detected in 33%. Of 1,668 patients with chronic liver disease, 14% and 74% were positive for HCV RNA and HBsAg, respectively. Nearly 80% of non-B chronic liver disease were negative for HCV RNA. The frequency of HCV RNA in chronic liver disease was significantly higher in Hami (32%) and Shenyang (30%) than in other cities (6-12%). The HCV genotype distribution varied by region. Genotype III was detected in 46-70% of HCV infections in Hami, Shenyang, and Lanzhou, while more than 90% of patients from southern cities (Nanjing, Nanning, and Chengdu) had genotype II. No evidence for genotype I or IV infections was found. A full-length HCV genome sequence (HC-C2) derived from a Beijing patient with genotype II was closely related to previous isolates from Japanese and Taiwanese patients. These results suggest that HCV prevalence and genotype distribution vary from region to region in China, and that the HCV now predominant in China may have evolved epidemiologically with infections in Japan and Taiwan. The study identified a high frequency of non-B, non-C chronic liver disease in China, suggesting possibly a new agent or infections with extreme variants of HCV.

Molecular typing of hepatitis C virus genome from sera and liver tissues of patients with anti-HCV positive chronic liver disease

The authors investigated the distribution of HCV genotypes in patients with various chronic liver diseases in Korea. Study population was 70 individuals, positive for second generation anti-HCV EIA, consisting of 37 cases with sporadic non-A, non-B (NANB) chronic hepatitis (CH), 12 NANB hepatocellular carcinoma, 16 post-transfusion NANB hepatitis, 4 non-B blood donors and 1 healthy family member of a patient with sporadic CH. Molecular typing was performed by RT-nested PCR with type-specific primer sets deduced from the NS-5 region of HCV. The prevalence of type II was 75.0% and type III was 25.0% in sera. In liver tissues, type II HCV was shown in 63.0%, type III HCV in 3.7% and co-infections with type II and III HCV were observed in 18.5% of 27 samples biopsied. In the sera of patients with chronic hepatitis, typing results were relatively well correlated with those in tissues (75%), but type III could not be observed. Among 12 HCC patients, type III HCV appeared only in tissues, not in sera. These results suggest that type II HCV may be the major HCV type in Korea, and co-infections with type II and-III HCV may not be rare in chronic liver diseases with HCV.

Effect of alpha-interferon on hepatitis C virus chronic infection in mixed cryoglobulinemia patients

Since a striking association between hepatitis C virus (HCV) infection and mixed cryoglobulinemia has been demonstrated, the aim of this study is to investigate the effect of alpha-interferon (alpha-IFN) on HCV viraemia and clinico-serological manifestations of 15 patients (ten female and five male, mean [+/- SD] age 53 +/- 7 years). In 14/15 patients pre-study steroid dosage remained unchanged during treatment. alpha-IFN was administered at a dose of 2 x 10(6) IU daily for a month, then every other day for five months. On the whole, a statistically significant improvement of purpura (p < 0.001), serum transaminases (p < 0.001), and cryocrit (p < 0.01) was observed after alpha-IFN treatment. HCV viraemia was detected by polymerase chain reaction technique in 13/15 patients with mixed cryoglobulinemia and anti-GOR antibodies, expression of HCV-related autoimmunity, were present in 8/15. After alpha-IFN treatment, HCV RNA levels showed a clear-cut reduction in five persons and disappeared in another, while anti-HCV antibodies (Chiron ELISA and RIBA II) did not change after the six-month period of therapy. These data further support the possible etiopathogenetic role of HCV in patients with mixed cryoglobulinemia and suggest that alpha-IFN may be regarded as the elective treatment in this disease.

Isolate antibody to hepatitis C virus core antigen (C22) by RIBA-2: correlation with HCV-RNA and anti-NS5

The presence of circulating hepatitis C virus genome (HCV-RNA), elevated ALT levels and antibodies to an NS5-derived synthetic peptide have been examined in 13 subjects with isolate positivity for antibodies to the HCV core antigen (C22) on RIBA-2 testing. All subjects were followed up for 8-18 months (mean 12.4 months). In seven subjects (54%), intermittent or persistent viremia was associated with abnormal ALT levels (6 subjects) and with positivity for antibodies to NS5-peptide (6 subjects). On the other hand, in 6 out of 13 subjects (46%) no viral replication, no liver cytonecrosis and no antibodies to NS5 were found. It is concluded that isolate reactivity to C22 by RIBA-2 is a heterogeneous condition that corresponds to two distinct categories of subjects: those with active HCV infection and those without evidence of virus replication. Although HCV-RNA determination is the most reliable means of identifying HCV carriers, antibodies to NS5 can be a useful marker of virus activity. In fact, antibodies to NS5 were detected in 6 out of 7 viremic patients, compared to 0 out of 6 non-viremic patients (P = 0.004). It remains to be elucidated whether the isolate reactivity to core antigen found in non-viremic subjects represents a specific, HCV-induced antibody response, or is an unrelated crossreactivity.

Serum hepatitis C virus (HCV)-RNA and response to alpha-interferon in anti-HCV positive chronic hepatitis

Hepatitis C virus (HCV) replication was assessed before and during alpha-interferon (IFN) treatment in 22 anti-HCV positive patients with posttransfusion or sporadic chronic hepatitis (CH). Eleven patients were "responders" and 11 patients "non-responders" to IFN. Thirteen anti-HCV negative healthy subjects and five anti-HCV negative patients with autoimmune CH served as controls. Serum HCV-RNA was detected by the polymerase chain reaction (PCR) in all untreated anti-HCV positive patients but in none of the anti-HCV negative subjects. PCR primers from the 5'-noncoding (NC) region were more sensitive than primers from a non-structural (NS5) region in detecting HCV-RNA (21/22, 95% vs. 7/22, 32%, respectively). Positive strand HCV-RNA titre and positivity rate for the negative strand were similar in responders and non-responders before IFN treatment, as well as anti-c100-3 titre by enzyme-linked immunosorbent assay (ELISA), and anti-5-1-1, anti-c33c, anti-c22 positivity rate by immunoblot assay (RIBA). HCV-RNA positivity by both NC and NS primers was more frequent before IFN among responders. During IFN treatment, serum HCV-RNA was detectable, mostly at low titres, in 1 (NC positive) of the 11 responders and in 9 (4 NS positive and 5 NC positive) of the 11 non-responders. Among the four non-responders who were NS positive during IFN, three were NC positive before IFN. Serum HCV-RNA was always found in our post-transfusion or sporadic anti-HCV positive patients with CH. Viraemia generally decreased during IFN treatment, but no available HCV markers clearly distinguished responders from non-responders before IFN treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Sequence comparisons for a hepatitis C virus genome RNA isolated from a patient with liver cirrhosis

The nucleotide (nt) sequence was determined for an isolate of hepatitis C virus (HCV) derived from cirrhotic tissue of a patient with hepatocellular carcinoma. The 9408-nt sequence (EMBL Acq. No. X61596) showed homology of 90.7-91.4% on the nt level, as compared to two Japanese isolates from patients with a high titer of serum transaminase, 78.4-78.8% to those obtained in the United States, and 65.0% to that from an asymptomatic Japanese carrier. The phylogenetic tree of the six isolates classified them into three groups.

Comparison of several PCR procedures for detection of serum HCV-RNA using different regions of the HCV genome

Different methods for the isolation of hepatitis C virus RNA and several sets of primers from the 5' untranslated, core, NS3, NS3/NS4 and NS5 regions of the hepatitis C virus genome were used for the detection of the viral genome by the polymerase chain reaction. Serum samples from 10 patients with chronic hepatitis C and 10 healthy controls were studied. The best method for the RNA extraction was with cold guanidinium isothiocyanate followed by a denaturation step prior to the polymerase chain reaction. Using this method, the percentage of positivity to hepatitis C virus sequences in serum depending on the region amplified were: 5' untranslated, 90%; Core, 20%; NS3, 80%; NS3/NS4, 60% and NS5, 60%.

[Importance of PCR in the diagnosis of hepatitis C]

The identification of hepatitis C virus, based on DNA amplification, gives a precise estimation of the prevalence of the most frequent agent of NANB hepatitis. The first ELISA allowing the detection of anti-HCV antibodies, had too many false positive results and required the development of more sensitive and specific assays to confirm its results. PCR, allowing the hepatitis C virus diagnosis by showing directly HCV RNA sequences, offers a complementary approach to immunoserological tests. In blood donors with anti-HCV antibodies and with indeterminate or negative confirmatory tests, the finding of HCV RNA sequences reveals serum infectivity. During acute hepatitis, the delay in the appearance of anti HCV hampers acute phase diagnosis. The early detection of HCV RNA in peripheral blood, confirms the diagnosis and opens up therapeutic possibilities. In chronic hepatitis, the diagnosis of seronegative forms may only be resolved by PCR. Moreover, the presence of HCV RNA in peripheral blood represents the only marker of on-going viral replication and coincides with the severity of liver damage. During treatment with interferon, the follow up of HCV RNA sequences makes it possible to monitor its efficacy. The search for HCV RNA sequences directly in liver tissue shows that HCV may replicate in the liver in the absence of viremia. The presence of HCV RNA in the liver and the serum of liver transplanted patients is essential for the etiological diagnosis and management of hepatitis and bone marrow failure occurring after transplantation. Epidemiological study using PCR is a major tool in documenting vertical transmission between mother and child. Finally, PCR is important for the analysis of the HCV genome. Thus, in France there are at least three main strains, one close to the US prototype, the other close to the Japanese strain, possibly responsible for a more severe illness and a third one distinct from the previous two. However, its limits and constraints imply that PCR must not be considered as a routine assay. This emphasizes the need for more simple and rapid diagnostic tests, allowing the detection of HCV antigens and, as in hepatitis B, the progressive unravelling of the life cycle of HCV.

Full-length sequence of a hepatitis C virus genome having poor homology to reported isolates: comparative study of four distinct genotypes

Variable genomic sequences have been reported for RNA cloned from hepatitis C virus (HCV)-infected humans and chimpanzees. We found that four distinct genotypes of HCV could be differentially identified by PCR using type-specific primers. Full-length sequences have so far been reported for three of the four HCV genotypes, and we report herewith the sequence of the fourth type obtained from a Japanese blood donor. The entire nucleotide sequence of the HCV isolate (HC-J8) comprised 9481 bases plus a 3'-terminal poly(U) stretch of variable length. Like all previous isolates, the RNA contained a single, long open reading frame for a polyprotein of 3033 amino acids. HC-J8 differed from previously reported HCV isolates by 23.1-33.1% in nucleotide sequence and 15.9-28.8% in amino acid sequence. Based on genomic sequence homologies, a proposed phylogenetic tree of HCV, with a fourth branch represented by HC-J8, allowed a classification of all HCV isolates whose complete or partial sequences are now known. This classification suggests that all or most HCV genome sequences will fall into one of the proposed four types. The classification may be helpful in designing vaccine studies and for serological investigations of possible group- and type-specific antibodies.

A new type of hepatitis C virus in patients in Thailand

Partial nucleotide sequences in the tentative NS5 region of the hepatitis C viral genome obtained from patients with chronic hepatitis in Thailand were analyzed by reverse transcription followed by the polymerase chain reaction. Of ten samples studied, four showed low homologies to any known type of HCV: the homologies of the nucleotide sequences of these clones with HCV-J, -US, -K2a and -K2b were 66.5-69.1%, 66.5-68.2%, 61.2-64.1% and 64.4-66.2%, respectively, and the homologies of their deduced amino acids sequences were 71.7-75.2%, 71.7-75.2%, 69.0-72.6% and 69.9-73.5%, respectively. These four clones were classified a new distinct type of HCV, named HCV-T. Moreover, the nucleotide and amino acid sequence homologies of the four HCV-T clones showed that the HCV-T type could be classified into two genotypes, HCV-Ta and HCV-Tb.