Viral and host factors that contribute to efficacy of interferon-alpha 2a therapy in patients with chronic hepatitis C

Using conventional statistical analysis and multiple regression analysis, we investigated the viral and host factors that influence the response to recombinant interferon-alpha 2a therapy in patients with chronic hepatitis C. A total of 36 patients was randomly assigned to three administration schedules, 12 patients in each. Response to treatment was set as the criterion variable. Four variables were statistically significant in the conventional method in predicting a good therapeutic outcome: HCV genotype III and IV, lower histology activity index (HAI) score for liver, higher total dose of interferon administration, and lower serum HCV RNA concentration. In multiple regression analysis, a combination of the above four variables resulted in a higher multiple correlation coefficient (R = 0.84, P < 0.0001) using a stepwise method. Of those four, HCV genotype had the highest absolute value of standard partial regression coefficient (0.51). The HCV RNA concentration was correlated with HCV genotype and HAI score, whereas HCV genotype and HAI score showed no correlation. Thus, HCV RNA concentration was not statistically significant in multiple regression analysis. These findings indicate that HCV genotype, HAI score, and schedule of administration can be important predictors of the response to interferon therapy.

Treatment of chronic viral hepatitis

Recent advances have been made in the treatment of chronic viral hepatitis, mainly with recombinant interferon (IFN) alpha. However, the present treatment of chronic viral hepatitis is not entirely satisfactory because the efficacy is inconstant and/or incomplete. In chronic hepatitis B IFN-alpha induces a sustained interruption of hepatitis B virus (HBV) replication, with a HBeAg to anti-HBe seroconversion in about 30% of patients. Patients most likely to respond are those with no immunosuppression, HBV infection acquired during adulthood or active liver disease with low HBV replication. Responders usually show a significant decrease in serum HBV DNA levels during the first 2 months of therapy, followed by a significant increase in the level of aminotransferases. New nucleoside analogues might be useful in combination with IFN-alpha in the treatment of those who do not respond to IFN therapy. In chronic hepatitis B-D, the rate of sustained response to IFN-alpha therapy is low. To be effective, IFN-alpha must be used at a high dosage (9-10 mega units) with a long duration (1 year). In chronic hepatitis C, IFN-alpha at a dosage of 3 mega units over 6 months, induces a sustained response in about 20% of patients. A higher dosage of IFN (5-10 mega units) and a longer duration of treatment increases the rate of sustained response but is associated with poor tolerance. Non-responders to a first course of IFN do not respond to a second course of treatment. In patients who respond but relapse after treatment, the rate of sustained response after a second course of IFN needs to be assessed. Ribavirin, which has a significant antiviral effect on hepatitis C virus, might be useful in combination with IFN-alpha. At the dosage (3-6 mega units) usually used, IFN-alpha is relatively well tolerated. In about 10% of the patients therapy is interrupted, mainly because of severe fatigue, thyroid dysfunction or depression.

Hepatitis B virus subtypes and hepatitis C virus genotypes in patients with chronic liver disease or on maintenance hemodialysis in Indonesia

Hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) RNA were surveyed in patients in Yogyakarta, Indonesia, and their subtypes and genotypes were determined by serological methods and polymerase chain reaction with type-specific primers, respectively. Of 149 patients with chronic liver disease including 24 with chronic hepatitis, 86 with liver cirrhosis, and 39 with primary hepatocellular carcinoma, HBsAg was detected in 40 (27%) and HCV RNA in 48 (32%); one patient was positive both for HBsAg and HCV RNA. Thus, the cause of chronic liver disease was not identified in 62 (42%) patients. Of 58 patients on maintenance hemodialysis, four (7%) were positive for HBsAg and 44 (76%) for HCV RNA. Subtype adw was found in 34 (74%) of 46 HBsAg samples and adr in five (11%); compound subtypes, such as adyw and adyr were detected in the remaining seven (15%). Among HCV RNA samples from 48 patients with chronic liver disease, 23 (48%) were of genotype II, 17 (35%) of genotype III and one (2%) of genotype V, in a distribution strikingly different from that of 44 samples from patients on maintenance hemodialysis, 39 (89%) of which were of genotype I and only one (2%) of genotype II. Genotypes were not classifiable in seven (15%) patients with liver disease and four (9%) patients on hemodialysis despite high HCV RNA titers in them all. These results indicate that different HCV genotypes prevail in patients with distinct diseases, as well as unclassifiable HCV genotypes in Indonesia.

Analysis of hepatitis C virus genome in patients with autoimmune hepatitis type 2

BACKGROUND/AIMS

Hepatitis C virus (HCV) RNA is detectable in a proportion of patients with autoimmune hepatitis type 2, which is characterized by liver-kidney microsomal antibodies (LKM). Therefore, the genotype and sequence of HCV were studied in these patients.

METHODS

Sera from 43 LKM-positive and anti-HCV-positive patients (15 from Germany and 28 from Italy) and 82 LKM-negative and anti-HCV-positive patients (57 from Germany and 25 from Italy) were examined.

RESULTS

Genotyping revealed that the rate of genotype III HCV according to Okamoto's classification in patients with LKM antibody-positive autoimmune hepatitis type 2 was higher than in LKM-negative patients (22.0% vs. 2.4%; P < 0.05). This was because of an increase of genotype III in our patients from Italy. No HCV mutations were found that show a closer sequence homology to cytochrome P450IID6, the major LKM-1 antigen. Deletions in the envelope and nonstructural region 5 were found.

CONCLUSIONS

Because a specific HCV sequence is not associated with the induction of LKM-1 autoantibodies, future research must focus on host factors and possibly additional environmental factors.

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.

Serum collagen type IV for the assessment of fibrosis and resistance to interferon therapy in chronic hepatitis C

Sixty-nine patients with chronic hepatitis C (CH-C) were treated with interferon therapy, and serum collagen type IV (s-collagen IV) levels were measured by enzyme immunoassay to analyze the responsiveness to interferon therapy. Classified by the improved pattern of serum alanine aminotransferase levels after interferon administration, 23 patients were judged as sustained responders, 23 as transient responders, and 23 as non-responders. Fibrotic grades of the liver sample correlated statistically with the levels of s-collagen IV (P < 0.01). Pre-therapy s-collagen IV levels of sustained responders were significantly lower than those of the other responders, and only sustained responders showed a significant decrease of s-collagen IV levels after interferon therapy, in accordance with histologic improvement. Multivariate analysis showed that s-collagen IV and hepatitis C virus genotype were the most important factors affecting the response to interferon therapy of all variates. Thus, s-collagen IV is one of the most useful aids for the evaluation of liver fibrotic grade in CH-C and a potent predicting indicator for the responsiveness to interferon therapy.

Posttransfusion hepatitis C virus infection in children

Hepatitis C virus (HCV) infection was investigated retrospectively and prospectively in children who had open heart surgery. The retrospective study included 196 patients who had open heart surgery 2 to 6 years before enrollment and were regularly followed. Antibody to HCV was detected in eight cases, and seven of these eight patients had viremia caused by HCV infection. The other patient's anti-HCV titer gradually decreased and HCV ribonucleic acid was absent throughout the course. Four of these eight had persistent viral replication without clinical evidence of hepatitis; the other three had viremia and chronic hepatitis. The HCV infection rate in the retrospective study group was about 4%. The HCV was of genotype 2 in five cases and of genotype 3 in two cases. The clinical outcome was not related to sex, age, amount of transfusion, or HCV genotype. For the prospective study, we enrolled 94 patients. Of the 56 enrolled after the initiation of anti-HCV screening in the blood bank, none was infected by HCV. Of the 94 patients, 38 were enrolled before screening; 4 had abnormal liver function 1 to 3 months after operation, and 2 were infected with HCV. One patient had an acute but resolving course; the other had persistent anti-HCV and HCV viremia, although the liver function test results returned to the normal range. The HCV in both cases belonged to genotype 2. We conclude that in Taiwan the seroconversion rate of HCV in children who underwent open heart surgery was 4% to 5%. Anti-HCV screening in donor blood significantly decreased the incidence of posttransfusion hepatitis C.

Characterization of the 5' noncoding and structural region of the hepatitis C virus genome from patients with non-A, non-B hepatitis responding differently to interferon treatment

We examined 14 patients with hepatitis C caused by infection with the hepatitis C virus-II genotype to understand differences in responsiveness to interferon. The patients were classified into two groups according to their response to interferon: eight responding and six non-responding patients. The 5' noncoding and structural regions of the hepatitis C virus-II genome from each patient specimen were amplified by reverse transcription followed by the polymerase chain reaction. The nucleotide sequences of these amplified DNAs were then determined. By comparing the nucleotide sequences and the deduced amino acid sequences of samples from both groups, no group-specific sequence was observed in the analyzed regions despite the presence of considerable sequence diversity. However, additional cysteine residues were observed in half the responding group. The degree of micro-heterogeneity in hypervariable region 1 of the hepatitis C virus in relation to the sensitivity to interferon treatment was also examined; however, no significant correlation was observed. In addition, frequent alterations in the amino acid sequences were observed in hypervariable region 1 during the course of interferon treatment.

Predicting interferon therapy efficacy from hepatitis C virus genotype and RNA titer

We classified 53 Japanese patients with chronic hepatitis C who were treated with natural interferon-alpha into genotypes and also tested the amounts of hepatitis C virus (HCV) RNA. The rate of the long-term complete response group, whose alanine aminotransferase levels remained within the normal range during the six months after therapy, was significantly higher (P < 0.01) in the type-III patients (4/5, 80.0%) than in type-II patients (4/43, 9.3%). For these long-term complete responders, the amounts of HCV RNA was less than 10(7) copies/ml serum in type-II patients, whereas two type-III patients with relatively high amounts of HCV RNA responded completely. These results confirm that the genotype of HCV is an important factor for predicting the response to interferon therapy. The amounts of HCV RNA can also predict its efficacy in type-II patients.

Factors predictive of response to interferon-alpha therapy in hepatitis C virus infection

To determine the patient-dependent and virus-related factors that may predict sustained response to interferon-alpha therapy, we prospectively evaluated 60 consecutive patients with chronic hepatitis C who received a standardized treatment schedule of interferon-alpha. Twenty-eight patients achieved a long-term sustained remission, 14 patients had temporary responses during treatment but relapsed after completing it and 14 patients did not respond. Four patients dropped out because of severe side effects and were excluded from evaluation of efficacy. Twenty-one variables were chosen as possible predictors of sustained response and were analyzed by means of multivariate analysis. Variables related to the hepatitis C virus included genotype and concentration in serum before treatment. The former was determined by means of the polymerase chain reaction with genotype-specific primers for genotypes PT, K1, K2a and K2b, which were deduced from nonstructural region 5 of the hepatitis C virus genome. The latter was measured with a competitive polymerase chain reaction technique. Three variables were statistically significant (p < 0.05) on univariate analysis: viral genotype, pretreatment level of viremia and Knodell's fibrosis score. In multivariate analysis viral genotype and Knodell's fibrosis score were correlated independently with a sustained response (p < 0.05 for both). Incidence of sustained response was 40% and 91% in patients with genotypes K1 and K2a, respectively. We conclude that with the treatment schedule used, viral genotype was the most useful predictor of a sustained response to treatment with interferon-alpha.

Comparison of the sensitivity of nested PCR in the 5' non-coding and the NS5 regions of the HCV genome

Thirty-seven patients with antibodies to hepatitis C virus detected by second-generation enzyme-linked immunoabsorbent assay were studied. Serum of 20 patients with increased serum alanine aminotransferase and 17 patients with normal serum alanine aminotransferase levels was tested for hepatitis C virus RNA with reverse transcription and nested polymerase chain reaction. The nested polymerase chain reaction was independently performed in both the 5' non-coding region and putative non-structural 5 region. The results of these 37 sera were: 28 5' non-coding region polymerase chain reaction positive (17 with increased alanine aminotransferase) and 13 non-structural 5 region polymerase chain reaction positive (8 with increased alanine aminotransferase). Eighteen of the 20 patient with increased alanine aminotransferase (90%) and 11 of the 17 patients with normal alanine aminotransferase (65%) were polymerase chain reaction positive. Of the 28 5' non-coding region polymerase chain reaction positive subjects, 16 were non-structural 5 region polymerase chain reaction negative. The failure to amplify hepatitis C virus-RNA using the non-structural 5 region primers in these patients may be related to the higher genetic variability in the non-structural 5 region than in the 5' non-coding region. Overall, the 5' non-coding region polymerase chain reaction provides a more reliable test for the diagnosis of hepatitis C virus. However, a recombinant immunoblot assay-2 indeterminate patient with increased alanine aminotransferase was polymerase chain reaction negative in the 5' non-coding region and polymerase chain reaction positive in the non-structural 5 region. For this patient, the specificity of the non-structural 5 amplified product was confirmed by hybridization and sequencing.

Geographical distribution of hepatitis C virus genotypes in blood donors: an international collaborative survey

The frequency of infection with the six classified major genotypes of hepatitis C virus (HCV) was investigated in 447 infected volunteer blood donors from the following nine countries: Scotland, Finland, The Netherlands, Hungary, Australia, Egypt, Japan, Hong Kong, and Taiwan. Viral sequences in plasma from blood donors infected with HCV were amplified in the 5'-noncoding region and were typed by restriction fragment length polymorphism analysis. Electrophoresis of DNA fragments produced by cleavage with HaeIII-RsaI and ScrFI-HinfI allowed HCV types 1 (or 5), 2, 3, 4, and 6 to be identified. Further analysis with MvaI-HinfI allowed sequences of the type 5 genotype to be distinguished from sequences of the type 1 genotype. Types 1, 2, and 3 accounted for almost all infections in donors from Scotland, Finland, The Netherlands, and Australia. Types 2 and 3 were not found in the eastern European country (Hungary), where all but one of the donors were infected with type 1. Donors from Japan and Taiwan were infected only with type 1 or 2, while types 1, 2, and 6 were found in those from Hong Kong. HCV infection among Egyptians was almost always by type 4. Donors infected with HCV type 1 showed broad serological reactivity with all four antigens of the second generation Chiron RIBA-2 assay (Chiron Corporation, Emeryville, Calif.), while infection with divergent HCV genotypes elicited antibodies mainly reactive to c22-3 and c33c. Reactivities with antibodies 5-1-1 and c100-3 were infrequent and were generally weak, irrespective of the geographical origin of the donor. Because the envelope region of HCV is even more variable than the NS-4 region, it is likely that vaccines based on these proteins need to be multivalent and perhaps specifically adapted for different geographical regions.

Serum hepatitis C virus RNA quantity and histological features of hepatitis C virus carriers with persistently normal ALT levels

We studied hepatitis C virus carriers with normal liver function to evaluate the histological features of their livers and the replicative levels of hepatitis C virus. Liver biopsies were performed in 22 hepatitis C virus carriers with persistently normal ALT levels. Hepatitis C virus RNA in serum was quantified with a competitive assay that combined reverse transcription and the polymerase chain reaction, which is based on co-amplification of the target RNA with known amounts of synthetic mutated RNA. Three patients had normal livers on histological study, whereas the other 19 had chronic persistent hepatitis, with lymphoid infiltrates or aggregates in portal tracts commonly observed but intralobular inflammatory changes absent or minimal. The titer of hepatitis C virus RNA (logarithmic transformed copy number per milliliter of serum) varied from 4.0 to 8.0 (mean +/- S.D.: 6.3 +/- 1.1); it was significantly lower in the three patients with normal livers (4.3 +/- 0.2) than in those with chronic persistent hepatitis with mild (6.4 +/- 0.8, n = 11) or moderate (7.1 +/- 0.5, n = 8) portal inflammation. The titer of hepatitis C virus RNA was correlated with the total score (r = 0.68) and the score for portal inflammation (r = 0.68) in the histological activity index. These results indicated that there seem to be "healthy carriers" of hepatitis C virus with extremely low levels of viral replication. However, in most hepatitis C virus carriers with persistently normal ALT levels, there are inflammatory changes in the portal tracts, with severity depending on the replicative levels of hepatitis C virus.

New genotype of hepatitis C virus in South Africa

Partial nucleotide sequences in the core region of the hepatitis C viral genome were determined by reverse transcription followed by polymerase chain reaction, in a patient with chronic hepatitis from South Africa. These nucleotide sequences showed a low degree of homology with known types of HCV: the degree of homology between the nucleotide sequences of these clones with HC-J1, J4, J6, J7, Tr, and Eb-1 were 86.1-87.3%, 87.3-87.9%, 83.0-83.9%, 81.1-82.0%, 81.0-82.2%, and 82.8-83.4%, respectively, and that the deduced amino acid sequence homologies between these clones and HC-J1, J4, H6, J7, Tr, and Eb-1 were 90.7-91.6%, 89.7-91.6%, 91.6-93.5%, 90.7-91.6%, 81.5-82.4%, and 89.2-90.2%, respectively. The nucleotide sequence homologies of these clones with HC-J1, J4, J6, J7, Tr, and Eb-1 were very low, compared to those between the same genotype. Further comparison using molecular evolutionary methods suggested that this sequences should be classified in a new genotype.

Rolling review--the pathogenesis, diagnosis and management of viral hepatitis

Five major hepatotrophic viruses have been identified. The pathogenesis, diagnosis and treatment of chronic viral hepatitis continues to be intensely researched. Experimental evidence suggests that HLA restricted virus-specific T cells play a role in hepatocellular injury in type A hepatitis. The absence of chronic infection indicates the effectiveness of the host immune response to hepatitis A virus (HAV). It is postulated that HAV may rarely trigger an autoimmune chronic hepatitis. Active prophylaxis of hepatitis A is possible. The elimination of hepatitis B is dependent on the recognition of viral determinants in association with HLA proteins on infected hepatocytes by cytotoxic T cells. The specific epitopes recognized by B and T cells are being mapped. Polymerase chain reaction (PCR) amplification and sequencing of genomic DNA in patients with chronic hepatitis B has indicated that nucleotide substitutions in the genome are not uncommon. Their pathogenicity is being explored. Antiviral therapy for hepatitis B remains difficult. Interferon is effective in a proportion of patients. Thymosin may prove to be more effective immunomodulatory therapy. New nucleoside analogues suppress HBV replication, but the safety of these drugs has been questioned after the appearance of severe liver toxicity with fialuridine. The data that hepatitis D virus is pathogenic has recently been challenged with the observation that HDV re-occurs in transplanted liver after engrafting, but without signs of HBV recurrence or evidence of liver damage. Treatment of hepatitis D virus remains difficult. Several isolates of hepatitis C virus have been cloned, and the sequence divergence of these isolates indicates that there are several major genotypes and component subtypes of this polymorphic virus.(ABSTRACT TRUNCATED AT 250 WORDS)

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)

Transmission of hepatitis C virus from mothers to infants. The Vertical Transmission of Hepatitis C Virus Collaborative Study Group

BACKGROUND

Although there are case reports of vertical transmission of hepatitis C virus (HCV), it remains uncertain to what extent infected mothers transmit this virus to their infants.

METHODS

We investigated the transmission of HCV from infected mothers to their babies by analyzing HCV RNA in the blood. Three independent studies were performed. First, 7698 parturient women were tested for anti-HCV antibodies; 53 were positive. Their 54 infants (including one set of twins) were followed prospectively for at least six months and tested for HCV disease were prospectively studied. Third, the families of three HCV-infected infants were examined retrospectively.

RESULTS

Of the 53 antibody-positive mothers, 31 were also positive for serum HCV RNA: Three of the 54 babies born to these mothers (5.6 percent) became positive for HCV RNA during the follow-up period. None of the babies of the 22 women who were antibody-positive but HCV RNA-negative became positive for HCV RNA: In the second study, HCV RNA was detected in one of the six infants of infected mothers. In the third study, HCV RNA was detected in the mothers of the three HCV-infected infants. In each of the seven infected infants we studied, the genomic sequence of HCV was almost identical to that from the mother. These seven mothers had significantly higher titers of HCV RNA than did the mothers of infants with no evidence of infection (mean [+/- SD], 10(6.4 +/- 0.5) vs. 10(4.4 +/- 1.5) per milliliter; P < 0.001).

CONCLUSIONS

HCV is vertically transmitted from mother to infant, and the risk of transmission is correlated with the titer of HCV RNA in the mother.

Genotypes and titers of hepatitis C virus for predicting response to interferon in patients with chronic hepatitis C

Interferon induces remission in about 50% of patients with chronic hepatitis C, but it is difficult to predict which patients will respond. Host and viral factors were evaluated for correlation with response to interferon in patients with chronic hepatitis C. Recombinant interferon alpha-2b with a total dose of 480-560 million units was given to 136 patients, of whom 74 (54%) responded. Genotypes of hepatitis C virus (HCV) in sera, I, II, III, IV, and V, were determined by polymerase chain reaction (PCR) with type-specific primers. In 72 patients, pretreatment levels of HCV RNA were titrated by PCR in serial tenfold dilutions of RNA extracted from serum. Response to interferon occurred in 34 (40%) of 85 patients infected with HCV of genotype II, less frequently than in 22 (85%) of 26 with genotype III (P < 0.001) or in 7 (70%) of 10 with genotype IV. Of 51 patients with genotype II HCV, 6 of 8 (75%) with HCV RNA titers < 10(6) responded, more frequently than 4 of 43 (9%) with titers > or = 10(6) (P < 0.001). Responders were younger than non-responders (45.7 +/- 11.7 vs. 50.3 +/- 9.6 yr) and had received transfusions less frequently (26/74 or 35% vs. 37/62 or 60%, P < 0.01). Response to interferon correlated inversely with the severity of liver histopathology. These results indicate that response to interferon is influenced by HCV genotypes and pretreatment levels of HCV RNA in serum.

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.

Analysis of the core and E1 envelope region sequences of a novel variant of hepatitis C virus obtained in Indonesia

Hepatitis C virus (HCV) is currently classified into 6 major types, HCV-1 through -6, each of which can be further divided into a few subtypes, e.g., HCV-1a, -1b, -1c, etc., on the basis of sequence variation of the viral genome. The core and E1 envelope regions of HCV genome were amplified from sera of Indonesian patients using reverse transcription-polymerase chain reaction. Sequence analysis of both core and E1 regions followed by molecular evolutionary phylogenetic analysis identified a novel sequence variant of HCV-1 (Td-6). Antibodies in the serum from which Td-6 was isolated reacted only marginally to the core protein of HCV-J, a representative strain of HCV-1b, despite strong antibody response against a mixture of the core, NS3 and NS4 proteins of HCV-1a. The possible mechanism for the diminished reactivity of the antibodies in the serum to the core protein of HCV-J is discussed.

Seroreactivity and genomic amplification profile of hepatitis C virus from patients with chronic liver disease in India

Patients with chronic liver disease were screened initially for antibodies to the hepatitis C virus using commercially available assay systems. Positive sera were tested for amplification of the 5' noncoding region, and putative structural and nonstructural genomic regions of hepatitis C virus by reverse transcription-polymerase chain reaction. Eight out of 22 patients who were seropositive showed presence of viral RNA by amplification from genomic regions. Sera from four subjects showed amplification of the 5' noncoding region, a different serum showed amplification of the capsid region, and three other sera showed amplification of the nonstructural genomic region of the virus. An amplification profile of the RNA-positive samples suggests genomic sequence divergence of hepatitis C virus circulating among Indian patients.

Prevalence of hepatitis C virus with different genotypes determined by a group-specific antibody assay in Japanese patients with chronic liver diseases due to hepatitis C virus infection

Hepatitis C virus (HCV) genotypes (groups I and II) were determined by a newly developed C14 assay in which antibodies against group-specific recombinant proteins of the NS4 region were measured by ELISA (enzyme-linked immunosorbent assay). The genotypes determined by the C14 assay were compared to those determined by a polymerase chain reaction (PCR) in 50 patients. The HCV genotypes determined by both methods were consistent in 78% of the patients. The results of the assays were not contradictory in any patient. The sensitivity of the C14 assay was as high as over 90%. Frequency of HCV genotypes was studied in 300 patients with chronic liver diseases type C by using the C14 assay. The prevalence of groups I and that of II in patients with chronic hepatitis were 73% and 21%, the correspondence figures in those with liver cirrhosis 80% and 13%, and in those with hepatocellular carcinoma 81% and 13%, respectively. The clinical characteristics were similar between the patients with group I and II HCV infections in each disease category. In conclusion, the C14 assay is useful for epidemiological studies of HCV genotypes, and group I is a major HCV genotype of chronic liver diseases type C in Japan.

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.

Identification and genotyping of hepatitis C virus in injectable and oral drug users in New Zealand

BACKGROUND

Hepatitis C virus infections are known to be common in injectable drug users (IDU) both in New Zealand and overseas. Little is known of the hepatitis C genotype frequency in this population.

AIMS

To confirm the high incidence of hepatitis C virus infections in IDU and compare this with the frequency in oral drug users (ODU) as well as identify the pattern of hepatitis C genotypes present.

METHODS

Use was made of an experimental nucleocapsid assay as well as a conventional anti-HCV assay. HCV-RNA was identified using a polymerase chain reaction (PCR) technique and a variation of this method was used for HCV genotyping.

RESULTS

Seventy-four per cent of IDU were reactive for anti-HCV in both types of assay. PCR testing detected several more reactive samples. Dominant genotypes were Types I and V, but Type IV was not detected. Mixed infections were noted in some patients. There was a low frequency of anti-HCV in ODU.

CONCLUSIONS

Hepatitis C virus infections are a problem in IDU in New Zealand, and additional public health measures may be required. The distribution of genotypes of HCV-RNA are similar to those seen in other Western countries.

Hepatitis C virus serological and polymerase chain reactions in human immunodeficiency virus-positive and -negative patients

BACKGROUND

Polytransfused patients may be dually infected with hepatitis C virus (HCV) and human immunodeficiency virus (HIV).

OBJECTIVES

To assess the correlation of antibodies to HCV with viral RNA in serum as determined by polymerase chain reaction (PCR) in anti HIV-positive and -negative haemophiliacs.

STUDY DESIGN

Serum from 150 Patients with or without HIV infection were examined for anti-HCV by second generation enzyme-linked immunosorbent assay (ELISA) and recombinant immunoblotting assay (RIBA). A sample was also tested in a nested-reverse transcription PCR for a conserved sequence of the 5' untranslated region of HCV. PCR-positive specimens were titrated and a type-specific PCR using viral core gene sequences was used to determine distribution of HCV viral types.

RESULTS

Eighty-seven percent of the patients were positive in ELISA. All the positives but 2 were either positive of indeterminate in RIBA. The frequency of indeterminate RIBA results was 33% among HIV-positive subjects and less than 1% among HIV-negative ones. PCR was positive in 68% of 73 RIBA-positive or -indeterminate individuals and negative in all HCV-seronegative individuals examined. No significant differences were observed in HCV viral type, prevalence or titers of viraemia between HIV-positive or -negative patients.

CONCLUSIONS

The majority (68%) of anti-HCV-positive haemophiliacs examined in this study had HCV RNA in their sera and anti-HCV profile determined by RIBA had no apparent influence on viraemia. The presence of HIV infection in these patients had no significant impact on HCV RNA prevalence, titer or HCV type distribution.

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.

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.

Interferon treatment of chronic hepatitis C

The natural history of chronic hepatitis C is just beginning to be clarified, with its more common course being an insidiously progressive liver disease that often remains clinically inconsequential for many years or even decades. Although chronic hepatitis C progresses histologically, the impact on the clinical well-being of the patient is less evident. Interferon is an effective therapy for this disease because of its antiviral effect on the cytopathic hepatitis C virus, lowering serum alanine aminotransferase (ALT) levels, rather than because of any immune modulatory mechanism. Unfortunately, interferon therapy does not permanently eradicate hepatitis C virus in the majority of patients, and relapse with return of the serum ALT level to the pretreatment range occurs in approximately 70% of responding patients. Other interferon-treated patients continue to be viremic and are not considered to be responders. In addition, not all patients with chronic hepatitis C require treatment. A systematic approach to patient evaluation is necessary to determine the need for treatment, assess treatment response, identify side effects of therapy, and assist in other clinical decisions.

Prevalence of hepatitis C virus genotypes in Italy

Hepatitis C viruses (HCV) present in 110 Italian patients were characterized by genotype-specific PCRs. Among the 65 cases of community-acquired hepatitis, HCV genotype II was dominant (60%), followed by genotypes IV (15%), III (11%), and I (3%). Among the 45 hemophilia-associated cases, the distribution of the four HCV genotypes was markedly different: genotype I was the most prevalent (61%), followed by genotypes II (25%), III (4%), and IV (2%). Double infections were observed in eight patients. Two HCV remained unclassified. For the 45 community-acquired cases from which a liver biopsy was available, genotype II was associated with more severe liver damage than the other types.

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.

Serum hepatitis C virus RNA levels in chronic hepatitis C--importance for outcome of interferon alfa-2b treatment

Sera from 39 out of 40 patients with chronic hepatitis C virus (HCV) infection who had been treated for 60 weeks with interferon alfa-2b proved initially HCV RNA positive by reversed transcriptase polymerase chain reaction (PCR). These patients were analysed for genotype and quantitatively for HCV RNA levels prior to treatment by using a competitive PCR method with colorimetric detection of the amplified products. HCV RNA levels were correlated to outcome of treatment, mode of acquisition, histology and HCV genotype. The median pretreatment HCV RNA level in sustained responders (n = 15) with eradication of the viremia and normalization of serum ALT levels lasting 24 weeks post treatment was significantly lower than that in the combined group of non-sustained responders (n = 9) and non-responders (n = 15), 2.52 x 10(5) vs 8.90 x 10(5) genome equivalents per ml serum, p < 0.0125, respectively. 10 out of 17 patients with HCV RNA levels lower than the median level (5.64 x 10(5) genome equivalents per ml serum) had a sustained response to interferon treatment versus only 5/22 with levels equal to or higher than the median level, p = 0.04. No significant pretreatment differences in median HCV RNA levels according to mode of acquisition, genotype, or liver histology prior to treatment were seen. It is concluded that a low pretreatment HCV RNA level seems to be indicative of a sustained response to interferon alfa-2b treatment, whereas a high level seems to be indicative of a non-sustained or non-response. In the individual patient, however, the levels varied widely irrespective of response category.

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.

Intrafamilial transmission of hepatitis C virus

The intrafamilial transmission pattern of hepatitis C virus (HCV) was examined in 118 family members of 61 index patients with type C chronic liver disease using anti-HCV antibodies and HCV RNA assay. The study subjects consisted of eight parents, 49 spouses, 50 children, eight siblings and three other relatives. The positivity rates of anti-C100, anti-JCC, second-generation anti-HCV and HCV RNA were 6.8, 12.7, 12.7 and 11.0%, respectively. Positivity in one or more anti-HCV antibody assay was detected in 3/24 (12.5%) father-child pairs, 3/17 (17.6%) mother-child pairs, 2/8 (25%) sibling pairs, 6/38 (15.8%) husband-wife pairs and 2/13 (15.4%) wife-husband pairs. In spouses, positivity for anti-HCV antibody or HCV RNA was observed after 40 years of age. None of 11 spouses married < 15 years was positive for any anti-HCV assay or HCV RNA. In spouses whose age was > 50 years and duration of marriage was > 25 years, anti-HCV or HCV RNA was frequently detected (32.0%). However, when seven pairs involving four spouses, one mother-daughter pair and two sibling pairs were subtyped, the same HCV subtypes were found in only four pairs (type II in three pairs and type III in one pair). Further, the agreement rate between anti-HCV and HCV RNA was > 90%. These results suggest that intrafamilial transmission of HCV, revealed by the subtyping method, is considered lower than the percentage of positivity for anti-HCV antibodies or HCV RNA in family members of patients with type C chronic liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitation and typing of serum hepatitis C virus RNA in patients with chronic hepatitis C treated with interferon-beta

We quantified serum hepatitis C virus RNA titers and determined hepatitis C virus subtypes in chronic hepatitis C patients treated with interferon-beta to investigate relationships among serum ALT response, serum hepatitis C virus titer and hepatitis C virus subtype. Of 146 chronic hepatitis C patients who received interferon-beta therapy, 24 patients with sustained serum ALT normalization (complete responders) and 26 patients without serum ALT normalization (nonresponders) were randomly selected. Detection, typing and quantitation of hepatitis C virus were performed by means of the "single-tube" polymerase chain reaction method. Of the 24 complete responders, 21 (87.5%) became negative for hepatitis C virus RNA, whereas 21 (80.8%) of the 26 nonresponders remained positive. Hepatitis C virus infections with types I, II, III, IV, II + III and III + IV occurred in 0 (0%), 22 (51.2%), 10 (23.3%), 1 (2.3%), 7 (16.5%) and 3 (7.9%) patients, respectively. The mean pretreatment hepatitis C virus RNA titer of complete responders (0.4 +/- 2.0 x 10(4) CID50/ml) was significantly lower than that of nonresponders (3.8 +/- 4.5 x 10(4) CID50/ml) (p < 0.01). Regardless of HCV subtype, patients with more than 10(4) CID50/ml of HCV did not show serum ALT normalization, whereas complete serum ALT response was seen in most cases with less than 10(2) CID50/ml HCV. These results show that mixed infections with different hepatitis C virus subtypes appear to be more common than previously reported and that the pretreatment serum level of hepatitis C virus RNA is a more important predictor of outcome of interferon therapy than is virus genotype.

Importance of the polymerase chain reaction in the study of hepatitis C virus infection

Recently, the principal etiological agent of parenterally transmitted non-A, non-B hepatitis was molecularly cloned from the plasma of an experimentally infected chimpanzee and has been named hepatitis C virus. Determination of the complete nucleotide sequence of the hepatitis C virus genome was a crucial step in preparing the way for future study of this medically important human pathogen. Due to the very low concentration of virus in serum, amplification of viral RNA sequences by reverse transcription and polymerase chain reaction is the only practical method currently available for demonstrating viremia in patients with hepatitis C virus infection. This review examines the pivotal role of the polymerase chain reaction in understanding the biology of hepatitis C virus.

Factors useful in predicting the response to interferon therapy in chronic hepatitis C

To determine how various factors influence the response to interferon (IFN) therapy, we retrospectively studied 157 consecutive Japanese patients with chronic hepatitis C who received various treatment schedules of IFN. They were divided into two groups on the bases of outcome. One group was comprised of 65 patients who achieved a sustained normalization of serum alanine aminotransferase (ALT) levels for at least 6 months after treatment, while the other group was comprised of 84 patients with persistent elevation of serum ALT levels, despite treatment. Genotyping of hepatitis C virus (HCV) was done by polymerase chain reaction (PCR) with genotype specific primers, analysing the variations in nucleotide sequence within the NS 5 region of the HCV genome, namely genotypes PT, K1, K2a and K2b. We then used a multivariate analysis to determine the factors related to mode of treatment, patient characteristics and HCV genotype in relation to the response to IFN therapy. Of the 16 factors analysed, the HCV genotype (genotype K2a or K2b, P < 0.0008), treatment schedule (intermittent administration following a daily schedule, designated as combined schedule, P > 0.0014) and liver histology just before treatment (chronic persistent hepatitis or mild chronic aggressive hepatitis, P < 0.0324) were the most strongly correlated with a normalizing response to IFN therapy. These results suggest that not only are the IFN treatment schedule and patient profile significant, but the properties of the virus also influences the response. However, as the IFN treatment schedule is the only changeable factor, it should be designed to maximize the benefit of IFN therapy.

Virological features of hepatitis C virus infection in hemodialysis patients

The clinical and epidemiological relevance of circulating antibodies to hepatitis C virus (HCV) in hemodialysis patients is uncertain, since clinical signs of infection are often mild or absent, with alanine aminotransferase (ALT) values that are virtually always normal, and liver biopsies are only rarely performed. Determination of HCV RNA in serum is therefore critical for distinguishing chronic HCV infection from previous exposure to the virus. We studied HCV viremia by reverse transcription polymerase chain reaction (RT-PCR) in the 5'-noncoding region of the viral genome in 77 dialysis patients who were screened for anti-HCV by a second-generation enzyme-linked immunosorbent assay (the enzyme immunoassay II; Ortho HCV, 2nd generation, Ortho Diagnostic Systems Raritan, N.J.) and a second-generation recombinant immunoblot assay (Chiron Corporation and Ortho Diagnostic Systems) and prospectively evaluated for ALT elevations over a period of 5 years. Of 77 patients tested, 29 (38%) had active infection as shown by a positive PCR assay result, and of these, 26 were anti-HCV positive. Although a good correlation was found between circulating anti-HCV and HCV RNA in serum, 10 (28%) of 36 anti-HCV-positive patients were HCV RNA negative by PCR, suggesting either low levels of viremia or past exposure to HCV and subsequent recovery. On the other hand, 3 (7.3%) of 41 anti-HCV-negative patients had HCV RNA in their sera, indicating seronegative HCV infection. The ALT level had no predictive value for HCV infection, because it was repeatedly normal in 18 (62%) of 29 viremic patients. HCV genotyping was also performed and indicated that all four known genotypes of HCV were present in our group. In conclusion, serological assays are reliable for detecting exposure to HCV in hemodialysis patients; however, direct identification of the viral genome is required to document current infection.

[Correlation between hepatitis C virus (HVC) RNA and anti-HVC antibodies in a hemodialysis population]

Polymerase chain reaction (PCR) was applied to detect HCV-RNA in 75 hemodialyzed patients. Anti-HCV status was determined by ELISA-2 and by RIBA-2 for reactive samples by ELISA. ALT levels were monthly determined during the year preceding the end of the study. For 60 patients, anti-HCV serology was known since 1989 and 39 of them were tested for the presence of HCV-RNA at least four times during the 2 preceding years. The 9 patients who were negative for anti-HCV antibodies were negative by PCR. Of the 7 patients with an indeterminate profile by RIBA-2, 3 were positive by PCR: 1/1 with C-33c band only and 2/6 with C22-3 band only. Of the 59 patients reactive by RlBA-2, 57 were HCV-RNA positive. Of the 2 HCV-RNA negative patients, one had been PCR positive before interferon therapy. Of the 38 patients without acute hepatitis tested by PCR on 5 successive samples, all the specimens of 11 and 23 patients were HCV-RNA negative and HCV-RNA positive respectively. In 4 patients, a transient viremia was observed. The group of HCV-RNA positive patients had mean ALT levels greater than those who were negative. A correlation was established between HCV infection and both the time on dialysis and the number of blood transfusions. A high concordance (97%) was observed between antibodies to HCV and HCV-RNA.

Diagnosis and treatment of the major hepatotropic viruses

The hepatotropic viruses currently include hepatitis A, B, C, D, and E, and are associated with a spectrum of acute and chronic liver disease syndromes. The epidemiology and natural history of each are discussed, with emphasis on uncommon or newly recognized clinical presentations. The serodiagnosis of hepatitis A, B, and D is well established; the serodiagnosis of hepatitis C and E continues to evolve as serologic and virologic assays become refined. Hepatitis A and E only cause acute liver injury; current medical approaches therefore focus on vaccination strategies. Hepatitis B, C, and D can cause both acute and chronic liver injury. Sequelae of chronic liver disease, including portal hypertension and hepatocellular carcinoma, are not uncommon. Medical therapy of resulting chronic liver disease currently consists of interferon, though other anti-viral strategies are being explored. Advanced chronic liver disease due to hepatitis B, C, or D can be treated by orthotopic liver transplantation, but viral recurrence is near uniform and can be problematic. Further study of the hepatotropic viruses at the molecular biologic, epidemiologic, and clinical levels will continue to provide greater insight into the diagnosis and management of their associated clinical syndromes.

Genotype dependence of hepatitis C virus antibodies detectable by the first-generation enzyme-linked immunosorbent assay with C100-3 protein

Hepatitis C virus (HCV) samples in 155 sera, from patients with chronic non-A, non-B liver disease and blood donors, were grouped into four genotypes (I, II, III, and IV) by amplification of core-gene sequences by polymerase chain reaction with type-specific primers. HCV genotypes were compared with various HCV-associated antibodies detectable by the first-generation ELISA (ELISA-1) with C100-3 protein and a second-generation immunoblot assay with four recombinant HCV proteins. Antibodies to C100-3 protein and those to its subsequence (5-1-1) were detected in 13 (93%) and 12 (86%), respectively, of 14 sera with genotype I HCV; 56 (79%) and 58 (82%) of 71 sera with genotype II; 13 (34%) and 6 (16%) of 38 sera with genotype III; and 11 (34%) and 4 (13%) of 32 sera with genotype IV. Amino acid sequences of C100-3 of genotype I HCV are conserved by approximately 90% in genotype II, but only by approximately 75% in genotypes III and IV. The sensitivity of ELISA-1, therefore, would be influenced by heterogeneity in C100-3 sequences of different genotypes.

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.