Severity of liver disease with different hepatitis C viral clones

Influence of viral genotype and level of viremia on the severity of liver injury and the response to interferon therapy in Spanish patients with chronic C infection

BACKGROUND

We wanted to investigate the influence of viral genotype on the severity of liver injury and response to interferon and whether the level of viremia differs in accordance with genotype, severity of liver disease, and response to interferon in patients with hepatitis C virus (HCV) infection.

METHODS

We studied 118 patients with HCV-related liver disease. HCV genotypes were determined with a line probe assay, and serum HCV RNA levels with a competitive reverse transcription polymerase chain reaction assay.

RESULTS

HCV type 1b was the most prevalent genotype (88%). It was present in 100% of cirrhotic patients, with or without hepatocellular carcinoma (HCC), but only in 78% of patients with chronic hepatitis (P < 0.001). The response to interferon was better in patients infected with non-1b HCV genotypes (P = 0.002). In a multivariate analysis non-1b HCV genotypes and a low hepatic fibrosis correlated with a favorable response to interferon. Among patients with chronic hepatitis those infected with HCV type 1b were older (P < 0.001), and age was the only independent factor associated with HCV type 1b. Viremia levels differed neither between genotypes nor in response to interferon and was significantly lower in patients with cirrhosis and HCC.

CONCLUSIONS

HCV 1b was associated with more severe liver disease and a worse response to interferon therapy. Non-1b genotypes and a lower liver fibrosis were the only independent predictors of a favorable response to interferon. Levels of HCV viremia differed neither among different genotypes nor in response to interferon and decreased with advanced liver disease.

New hepatitis C virus (HCV) genotyping system that allows for identification of HCV genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5a, and 6a

Recent studies have focused on whether different hepatitis C virus (HCV) genotypes are associated with different profiles of pathogenicity, infectivity, and response to antiviral therapy. The establishment of a simple and precise genotyping system for HCV is essential to address these issues. A new genotyping system based on PCR of the core region with genotype-specific PCR primers for the determination of HCV genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5a, and 6a was developed. A total of 607 samples (379 from Japan, 63 from the United States, 53 from Korea, 35 from Taiwan, 32 from China, 20 from Hong Kong, 15 from Australia, 6 from Egypt, 3 from Bangladesh, and 1 from South Africa) were tested by both the assay of Okamoto et al. (H. Okamoto, Y. Sugiyama, S. Okada, K. Kurai, Y. Akahane, Y. Sugai, T. Tanaka, K. Sato, F. Tsuda, Y. Miyamura, and M. Mayumi, J. Gen. Virol. 73:673-679, 1992) and this new genotyping system. Comparison of the results showed concordant results for 539 samples (88.8%). Of the 68 samples with discordant results, the nucleotide sequences of the HCV isolates were determined in 23, and their genotypes were determined by molecular evolutionary analysis. In all 23 samples, the assignment of genotype by our new genotyping system was correct. This genotyping system may be useful for large-scale determination of HCV genotypes in clinical studies.

Differential prevalence of hepatitis C virus subtypes in healthy blood donors, patients on maintenance hemodialysis, and patients with hepatocellular carcinoma in Surabaya, Indonesia

Determination of the prevalence of liver disease caused by hepatitis C virus (HCV) of various genotypes helps provide an understanding of the virulences of these genotypes. Differences in the prevalences of these genotypes are known to exist in the various geographical regions of the world. Hence, we performed seroepidemiological and molecular epidemiological analyses of HCV in Surabaya, Indonesia. The prevalences of anti-HCV antibodies were 2.3, 76.3 and 64.7% in healthy blood donors, patients on maintenance hemodialysis, and patients with hepatocellular carcinoma (HCC), respectively. HCV-2a was the most common (52%) among the HCV clones obtained from blood donors; this was followed by HCV-1b (15%), HCV-1a (7%), and HCV-1d (7%), a unique Indonesian subtype. The high prevalence of HCV-2a in blood donors was further supported by serotyping analysis that could discriminate HCV type 2 (HCV-2a and -2b) from HCV type 1 (HCV-1a, -1b, and -1d). HCV-1a, -1b, and -1d were strongly associated with elevated serum alanine aminotransferase (ALT) levels in blood donors, suggesting a possibly more pathogenic feature of those subtypes than HCV-2a. In patients on maintenance hemodialysis, HCV-1a and -1b (each 31%) were among the most common subtypes, and in contrast to the case with blood donors, HCV-1a, -1b, and -1d were found in those with normal ALT as well as those with elevated ALT levels. Impaired immune responses of hemodialyzed patients might be responsible for the apparently decreased hepatocytic injury caused by infection with HCV type 1. In patients with HCC, HCV-1b (57%) was the most common; this was followed by HCV-1d (19%) and HCV-2a (5%). Subtype prevalence was not different between HCC patients with advanced liver cirrhosis and those without advanced cirrhosis.

Detection and typing of hepatitis C RNA in liver biopsies and its relation to histopathology

This paper describes the correlation of hepatitis C genotypes detected in liver tissue with histological grading (inflammatory activity) and staging (degree of fibrosis/cirrhosis). The viral genotype was analysed by type-specific polymerase chain reaction (PCR) and correlated with histology and age of patients. In 69 patients with chronic hepatitis C (HCV) infection, genotypes 1a and 1b were detected in 13 (18.8%) and 31 (44.9%) liver biopsies, respectively. Genotypes 2a and 2b were each detected once (1.5%) and 12 (17.4%) tissue samples showed a mixed infection with two genotypes. In 11 (15.9%) biopsies, no genotype could be established. The liver specimens were grouped according to the presence or absence of genotype 1b: group A consisted of specimens infected with genotypes 1a, 2a, and 2b (n = 16), Group B contained biopsies infected with genotype 1b (n = 42), and group C were biopsies with no detectable genotype (n = 11). Activity (grade) of chronic hepatitis was not different in these three groups. However, advanced fibrosis/cirrhosis was observed in 16 (38.1%) biopsies in group B (containing genotype 1b), compared with none in group A (P = 0.01). The mean age of patients in group B was significantly higher than that in group A (P = 0.038), and the mean age of patients with advanced fibrosis was higher than that of patients with low fibrosis scores within these two groups (P = 0.004). Stepwise logistic regression revealed an independent association of age and genotype 1b (group B) with advanced fibrosis/cirrhosis. These data indicate that patients infected with genotype 1b have an higher risk of developing cirrhosis than do patients with other genotypes.

Serum hepatitis C virus titers in the progression of type C chronic liver disease. With special emphasis on patients with type 1b infection

The correlation of serum hepatitis C virus (HCV) titers to the progression of type C chronic liver disease remains controversial. We have investigated the relationship between serum HCV titers and different histological stages of chronic liver disease, including chronic persistent hepatitis (CPH), chronic active hepatitis and/or liver cirrhosis (CAH/LC), and hepatocellular carcinoma (HCC) in 94 well-characterized Taiwanese patients. The mean age of patients in the HCC group was significantly older than those in the CPH and CAH/LC groups, whereas those in the CAH/LC group had the highest mean serum alanine aminotransferase level among the three groups. The prevalence of HCV type 1b increased with the progression of histological severity, and the mean serum titer of the HCC group was significantly higher than that of CPH group. The difference of virus titers between the HCC group and those of the other two groups became more significant when only type 1b virus-infected patients were analyzed. In conclusion, elevated serum HCV titers are more frequently observed among Taiwanese patients with advanced type C chronic liver disease, an association not related to the high prevalence of HCV type 1b infection in such patients.

Hepatitis C virus subtype 3b infection in a hospital in Japan: epidemiological study

To elucidate the epidemiology of infection with hepatitis C virus (HCV) subtype 3b (a rare subtype thought to have originated in Southeast Asia) in Japan, we examined the genotypic subtype in 1397 patients with HCV-related chronic liver diseases. Of 1330 patients with identified HCV RNA genotypes. 960 had subtype 1b, 243 had subtype 2a, 97 had subtype 2b, 14 (1.1%) had subtype 3b, and 16 had other types of HCV or mixed subtypes. The age, gender, and severity of liver disease in patients with HCV subtype 3b did not differ from these features in patients with other subtypes. Eleven of the 14 patients with the 3b subtype had once worked at Company A in Tokyo, Japan. Multivariate logistic analysis showed that working history at that company was independently associated with the incidence of the subtype; the risk ratio was 207.2 (P < 0.0001). All 11 patients from Company A had received medical services, between 1953 and 1981, at Clinic C, which undertook medical care of the company staff. All 11 patients had received repeated intramuscular or intravenous injections for treatment of various diseases or for preventive vaccination for contagious diseases. The rare HCV subtype 3b, appeared to have been transmitted among the employees of a company through the performance of certain medical practices.

Hepatitis C virus genotypes in chronic hepatitis C of children

Several hepatitis C virus (HCV) genotypes have been recently identified and genotype 1b has been correlated with severe liver disease and a poor response to interferon therapy. HCV infection in children is an interesting model for evaluation of the relationship between HCV genotypes and liver disease, because of its relatively short duration and the infrequent association with confounding cofactors. We have investigated HCV genotypes, using a dot-blot hybridization assay with genotype-specific probes, in 36 Italian children with chronic hepatitis C who were otherwise well and had no other underlying disease. Only four patients were symptomatic; liver histology, obtained in 33 patients, showed minimal hepatitis in 17 and mild chronic hepatitis in 16. Infection with HCV genotype 1b was found in 55.5% of patients, with a peak prevalence of 83% in children from southern Italy (P < 0.05 vs other regions). The remaining children were infected with HCV genotype 1a (16.6%), genotype 2 (11.1%), and mixed (10.9%) or undetermined (2.7%) genotypes. In one patient, HCV viraemia was never detected. There was no statistically significant correlation between genotype and age, sex, source of infection, alanine aminotransferase pattern and histological activity index. These results indicate that genotype 1 b is widespread among Italian children with chronic hepatitis C, although with significant geographical variations. It is not associated with a more severe liver disease, therefore suggesting that the greater severity of liver disease recently reported in adults could reflect the cumulative effects of disease duration and of interfering cofactors.

Hepatitis C virus 1b is the dominant genotype in HCV-related carcinogenesis: a case-control study

In an ongoing case-control study in Athens on the etiology of hepatocellular carcinoma (HCC), an analysis was made in order to assess whether HCV genotype 1b is associated with hepatocellular carcinoma (HCC). The HCV genotype was determined in 17 HCC patients, 87 patients with chronic hepatitis C (CHC) without cirrhosis (NC-CHC) and 23 patients with CHC and cirrhosis (C-CHC). HCV genotype 1b was detected in 14/17, 16/23 and 23/87 of HCC, C-CHC and NC-CHC respectively. The age- and gender-adjusted odds ratios contrasting HCC with NC-CHC and C-CHC with NC-CHC were 8.3 and 3.8 respectively. These data strongly support the hypothesis that HCV 1b is a stronger liver carcinogen than other HCV genotypes, probably through increased HCV replication and enhanced liver cytopathicity.

Hepatitis C virus genotypes in the liver and serum of patients with chronic hepatitis C

OBJECTIVE: To evaluate the prevalence of hepatitis C virus (HCV) genotypes in a central area of Italy (Umbria); to analyze the correspondence of the genotypes detected in serum and liver samples; to study the relationship between HCV genotypes and severity of liver disease; to test whether co-infection with more than one HCV subtype could be influenced by the source of infection. METHODS: Genotyping by polymerase chain reaction with core-specific primers (Okamoto method) was performed in the serum and liver from 48 consecutive patients with histologically confirmed chronic C hepatitis. RESULTS: HCV genotype 1b was the prevalent strain and was not associated with more severe histologic damage. Data show a very good correspondence between genotypes identified in serum and liver specimens (91%). Mixed infections (with subtypes 1b and 2a) correlated significantly with intravenous drug abuse (p=0.001). CONCLUSION: We confirmed that subtype 1b is prevalent in central Italy. Co-infection with more than one subtype is not rare in intravenous drug abusers.

Pathogenesis of chronic hepatitis C and associated clinical manifestations

In 20% of patients exposed to hepatitis C virus, infection is transient but, after a few months, the patient remains susceptible to infection with the same strain. Protective immunity is short-lived. This suggests that recovery is related to the cellular immune response, which presumably lyses infected cells, and that the need during recovery for a virus-neutralizing anti-envelope response, is transient. In 80% of patients the infection is persistent, and it seems that antigenic variation of the envelope proteins allows the virus to escape neutralization by anti-envelope responses. The fact that this antigenic variation occurs at a much lower rate in agammaglobulinaemic subjects suggests that the major immune pressure producing this variation is humoral. How the virus-infected cells avoid lysis by cytotoxic T cells, which can be demonstrated in small numbers in the infected liver, remains unclear. The recent observation, that HCV infects CD8 lymphocytes, raises the possibility that virus infection of CD8 cells may impair their function and contribute to persistent infection. The mechanisms of production of cryoglobulin and of autoantibody formation are both unclear.

Genotype analysis of hepatitis C virus among blood donors and inmates in Metro Manila, The Philippines

Antibodies against hepatitis C virus (HCV) were detected in 18 (2.3%) of 800 sera from commercial blood donors and 23 (4.6%) of 502 sera from inmates in Metro Manila, the Philippines. The difference in the antibody prevalence between the two groups was statistically significant (P < 0.05). HCV RNA was detected in 14 (78%) of the 18 antibody-positive sera from blood donors and 19 (83%) of the 23 antibody-positive sera from inmates. Genotype analysis revealed that HCV-2a (7%). Among inmates, on the other hand, HCV-1a (68%) was most common, followed by HCV-1b (11%), HCV-2a (5%) and HCV-2b (5%). Overall, HCV-1a and HCV-1b appeared to be predominant among them. Thus, the genotype prevalence in the Philippines was distinct from those in other Southeast Asian countries such as Thailand, Vietnam and Indonesia, and also distinct from those in the Far East including Taiwan, Mainland China and Japan.

Hepatitis C and B virus infections in hepatocellular carcinoma. Analysis of direct detection of viral genome in paraffin embedded tissues

BACKGROUND

Although there have been many seroepidemiologic studies on hepatitis C virus (HCV) infection and hepatocellular carcinoma (HCC) occurrence, the actual role of HCV in hepatocarcinogenesis is unknown.

METHODS

We have previously reported on a highly sensitive method of detecting and identifying sequences of RNA genome in formalin fixed, paraffin embedded (FFPE) tissue by polymerase chain reaction (PCR) assay. Using this method, we carried out a retrospective study to determine the prevalence of HCV and hepatitis B virus (HBV) genomes in FFPE specimens from 102 Japanese patients with HCC.

RESULTS

HCV-RNA was detected by nested PCR reverse transcription (RT) in 64 of the 102 patients (62.7%), and 78.1% (50/64) of those HCV-RNA-positive patients had HCV genotype II. HCV-RNA was present in 54 of 70 (77.1%) anti-HCV-positive patients, and also in 5 of 20 (25%) anti-HCV-negative patients. HBV-DNA was detected by nested PCR in FFPE liver specimens from 21 of 102 (20.6%) patients. HBV-DNA positivity was consistent with seropositivity for serum HBV markers in 17 of these 21 patients (80.9%). HBV-DNA was present in FFPE samples from 2 patients who were seronegative for HBV markers, and in 1 patient who was seropositive for anti-HBs. Double infection of these two viruses was found in 6 patients (5.9%). Three patients (2.9%) were negative for both hepatic viral genomes and serum viral markers.

CONCLUSIONS

The precise prevalence of HCV and/or HBV infection among HCC patients can be determined by studying routinely-processed FFPE HCC samples preserved for up to 11 years using the technique of nested PCR. HCV-RNA was detected in the majority of our HCC cases; type II was the most common genotype of HCV encountered. The incidence of HCV-associated HCC was three times greater than that of HBV. Thus, the hepatitis virus infection most frequently associated, and probably ectologically implicated, with HCC in Japanese people is HCV infection.

Hepatitis C genotypes: current trends and future implications

OBJECTIVE

To review the geographic distribution and current understanding of hepatitis C virus (HCV) genotypes in regard to liver disease activity and response to treatment.

MATERIAL AND METHODS

We review the relevant medical literature and discuss our recent findings relative to chronic HCV infection and the importance of HCV genotypes.

RESULTS

HCV genotypes 1a and 1b are the most commonly found genotypes in patients with chronic HCV in the United States. Infection with HCV genotype 1b may be associated with more severe liver disease and may have a higher risk for the development of hepatocellular carcinoma. HCV genotype 2b seemed to be the most sensitive and HCV genotype 1b was the least sensitive to interferon therapy.

CONCLUSION

The identification of the infectious HCV genotype may be beneficial in clinical settings and may assist in the selection of patients who would benefit from interferon treatment.

Serotyping of hepatitis C virus in chronic type C hepatitis in Taiwan: correlation with genotypes

To evaluate the usefulness of a new serologic assay to group hepatitis C virus (HCV), genotypes identified by this serotyping method were compared to those identified by a polymerase chain reaction (PCR) assay with type-specific primers in 71 Taiwanese patients with chronic type C hepatitis. The group-specific antibodies against different HCV genotypes were detected by using an enzyme-linked immunosorbent assay (ELISA) based on group-specific recombinant peptides (C14-1 and C14-2) within the NS4 region. Among 71 patients positive for current second-generation HCV antibodies, HCV RNA was detected in 55 patients by PCR with primers from the 5' untranslating region, and in 52 by genotype-specific PCR. In 49 (89%) of 55 viremic patients, the results of serotyping by ELISA showed complete agreement with those determined by PCR genotyping, and none of the patients showed a group opposite to that of HCV genotype. The positive rate of group-specific antibodies (69/71;97%) was even better than that of the PCR (55/71;78%). We conclude that this new serotyping assay is highly sensitive and specific for the determination of HCV genotypes, and will be useful in future epidemiologic studies, as well for clinical application.

Response to interferon in chronic hepatitis C due to mixed genotype infection

We examined the response to interferon (IFN) in patients with chronic hepatitis C (CHC) due to two different genotypes of hepatitis C virus (HCV) infection. Among 64 CHC patients studied, one (2%) had HCV-RNA genotype I, 36 (56%) had genotype II, 19 (30%) had genotype III, 2 (3%) had genotype IV and 6 (9%) had both genotypes II and III. There was no significant difference in age, sex, history of blood transfusion and liver histology among patients with genotypes II, III and II + III. The HCV-RNA titre of genotype II patients was significantly higher than that of genotype III patients (P < 0.05). However, there was no significant difference in the HCV-RNA titre between genotype II + III and the other groups. The complete response rate achieved with IFN therapy was significantly higher in genotype III patients (74%) than in genotype II patients (17%; P < 0.01). Of the six patients with genotype II + III, a complete response to IFN was only achieved by two patients (33%), both of whom had a low HCV-RNA titre ( < or = 10(4.5) copies/mL) and HCV serotype 2. The remaining four patients had HCV serotype 1 and three of the patients had a high HCV-RNA titre ( > or = 10(5) copies/mL). The HCV genotype III was lost in two patients after IFN therapy. These data suggest that HCV-RNA titre and HCV serotype are important factors for predicting the efficacy of IFN therapy in patients with mixed genotype infection and show direct evidence of higher susceptibility towards CHC of patients with genotype III than genotype II.

Hepatitis C virus (HCV) subtype prevalence in Chiang Mai, Thailand, and identification of novel subtypes of HCV major type 6

Subtype analysis of hepatitis C viruses (HCVs) obtained from patients with chronic liver disease in Chiang Mai, Thailand, was performed. Of 46 HCV isolates, 13 (28%) were shown to belong to HCV subtype 3a (HCV-3a), 10 (22%) to belong to HCV-1a, 7 (15%) to belong to HCV-1b, 1 (2%) to belong to HCV-3b, and 1 (2%) to belong to a variant group, as determined from partial nucleotide sequences of the NS5B region of the viral genome. Analysis of 5' untranslated region sequences identified five other isolates (11%) of HCV type 1 and two other isolates (4%) of type 3. Detailed phylogenetic positions for the variant described above and those previously obtained from blood donors and drug addicts in Chiang Mai were determined by a six-parameter neighbor-joining method on the basis of core, E1, and NS5B region sequences. The results revealed that those sequence variants represent novel subtypes of HCV type 6. The HCV type 6 isolates appear to be antigenically different from isolates of HCV types 1 and 2, as determined by a serotyping method that utilizes recombinant peptides corresponding to a portion of the NS4 protein. The significance of subtype analysis around this area is discussed.

Genotyping of hepatitis C virus: coinfection by multiple genotypes detected in children with chronic posttransfusion hepatitis C

The distribution of genotypes of the hepatitis C virus (HCV) was studied in 24 children with chronic posttransfusion hepatitis C. Genotypes were determined by reverse transcription-nested polymerase chain reaction with type-specific primers. Twenty (83%) were infected by a single genotype: 14 by type II [1b], 3 by III [2a], and 3 IV [2b]. Four (17%) were coinfected by two genotypes. The amount of blood transfusion given to the patients infected by multiple genotypes was significantly larger than to those infected by a single genotype (mean +/- SD, 15.2 +/- 14.4 vs 78.6 +/- 42.0 U). Three of the four patients infected by multiple genotypes were considered to be immunocompromised by anticancer therapy for malignant disease. Eighteen patients showed a raised level of alanine aminotransferase throughout the follow-up, while the remaining six patients (three of type II [1b], two of IV [2b], and one of III [2a] + IV [2b]) achieved biochemical remission. Liver biopsy was performed on 19 patients. Compared to those with type III [2a] or IV [2b], those with type II [1b] appeared to show more severe histological changes with higher histological activity index scores, although there was no significant difference. The positive rates of antibody to C100-3 or 5-1-1 in patients with type III [2a] or IV [2b] were lower than in those with type II [1b] (33 and 33 vs 43 and 50%), whereas the antibody to C33C or C22-3 was detected in nearly all patients regardless of their genotypes. In the present study, we found a high incidence of multiple-genotype infection among children with chronic posttransfusion hepatitis C.

Pathophysiology and treatment of hepatitis C

Hepatitis C virus (HCV) infection is associated with a variable disease course and response to therapy. Some infected patients may develop little or no disease for 30 to 40 years, whereas others will develop cirrhosis within 5 to 10 years. Both host and viral factors influence the rate of disease progression. The management of patients is determined by the severity of their disease assessed by liver biopsy. Those with mild hepatitis without fibrosis do not require treatment but should undergo liver biopsy every 3 years. Patients with mild hepatitis with fibrosis, or with moderate or severe hepatitis with or without fibrosis, should be offered treatment. Interferon-alpha (IFN alpha) is currently the only licensed treatment for HCV infection. Although initial response rates to IFN alpha are high, over half the patients relapse and a sustained response is achieved in only 10 to 35% of patients. Higher doses of IFN alpha and a longer treatment duration are associated with better response rates. Treatment options for those who fail to respond to IFN alpha include a second course of IFN alpha at a higher dose or IFN alpha in combination with ribavirin, phlebotomy or ursodeoxycholic acid. At present, however, there are insufficient data to routinely recommend any of these options.

Prevalence, genotypes and antibody titer of hepatitis C virus in pregnant women in Taiwan

OBJECTIVES

To investigate the prevalence and genotypes of hepatitis C virus (HCV) in pregnant women in Taiwan, as well as to examine whether any correlation occurs between HCV genotype and anti-HCV titer.

METHODS

Forty-three pregnant women with positive anti-HCV and HCV-RNA were selected among 3,400 cases screened from January 1992 to March 1994. Each blood specimen was assayed for HCV genotypes by PCR method to detect HCV I, II, III and IV. Anti-HCV titer was determined by a second-generation EIA kit with serial dilutions.

RESULTS

Twenty-eight cases (65%) belonged to HCV II, 11 (26%) HCV III, 3 (7%) HCV IV and 1 (2%) HCV II+III. Besides, the anti-HCV titers in HCV II and HCV III groups were similar, ranging from 8x to 40,000x and revealing no statistical significance (p = 0.75).

CONCLUSIONS

Our data have verified that the prevalence rate of HCV infection in pregnant women is around 1.3% and no significant difference of anti-HCV titer occurs between HCV II and HCV III pregnant women.

Evaluation of a reverse hybridization assay for genotyping of hepatitis C virus

BACKGROUND/AIMS

Several strains of the hepatitis C virus exist; distinct genotypes and subtypes can be identified by sequence comparison of the viral genomes. Recent evidence that the genotype/subtype of hepatitis C virus may influence the clinical course of chronic hepatitis C and the response to interferon-alpha therapy for this disease suggests that methods to identify the genotype may become clinically useful. In the present study we evaluated a recently introduced reverse hybridization assay.

METHODS

HCV-RNA was isolated from serum samples from 61 consecutive patients attending our out-patient clinic and subsequently sequenced in the 5'-noncoding and the nonstructural-5 region by the dideoxynucleotide chain termination method. HCV-genotyping was performed by phylogenetic analysis of nonstructural-5 sequences. The amplification product for the reverse hybridization assay was obtained by "nested" polymerase chain reaction using biotinylated primers corresponding to the 5'-noncoding region. The assay is based on hybridization of the resulting polymerase chain reaction product with oligonucleotide probes immobilized as parallel lines on membrane strips.

RESULTS

According to the phylogenetic analysis of the nonstructural-5 region the prevalence of hepatitis C virus subtypes was as follows: 1a 18%, 1b 51%, 2a 3%, 2b 3%, 2c 7% and 3a 18%. The reverse hybridization assay correctly identified each hepatitis C virus genotype (1, 2, and 3). However, differentiation of hepatitis C virus subtypes was insufficient. 1/11 HCV-1a isolates was incorrectly classified by the reverse hybridization assay as HCV-1b and vice versa 3/31 HCV-1b isolates as HCV-1a. Classification of hepatitis C virus subtypes 2a, 2b and 3a was correct, but 4/4 HCV-2c isolates were misinterpreted by the assay as HCV-2a.

CONCLUSIONS

The reverse hybridization assay can differentiate between hepatitis C virus genotypes 1, 2, and 3, but is not completely reliable for hepatitis C virus subtyping.

Hepatitis C virus genotypes and severity of chronic liver disease in haemophiliacs

We studied the activity and stage of chronic liver disease in 45 HCV-seropositive/HIV-seronegative patients with severe haemophilia followed for at least 10 years. HCV-RNA was detected in serum in 36 patients (80%) Viraemic cases were further analysed for HCV genotypes: 10 (28%) were infected by type 1a, 10 (28%) by type 1b, seven (19%) by type 2, four (11%) by type 3, four (11%) had mixed infections (one by 1a + 1b, one by 1a + 2, one by type 2 + 3, and one by 1a + 2 + 3). ALT levels were within the normal range in 55% of the HCV-RNA negative patients but in only 11% of the viraemic cases. Results show a trend for higher levels of ALT in HCV-RNA-positive patients compared with those without viraemia (98 +/- 56 v 60 +/- 61), and particularly with patients with type 3 HCV infection (148 +/- 44). We suggest that a slow progression of chronic liver disease occurs in haemophilic HCV-positive/HIV-negative patients and conclude that presence of HCV-RNA in serum correlates well with cytolitic damage but, in the time-scale of our follow-up period, commonly used clinical-laboratory parameters cannot predict the chronic evolution of liver infection or identify differences in disease progression in relation to specific HCV subtypes.

Hepatitis C virus infection in an HIV-positive population in Normandy: antibodies, HCV RNA and genotype prevalence

The prevalence and the characteristics of hepatitis C virus infection (HCV) in 161 HIV-positive patients were studied. HCV seroprevalence was determined by enzyme immunoassay and recombinant immunoblot assay (RIBA). Two different reverse transcriptase polymerase chain reaction (RT-PCR) methods were also used to test the HCV-seropositive samples and 50 EIA-negative sera used as controls. The RNA HCV-positive sera were genotyped by the LiPA procedure. Associations of HCV status with demographic characteristics and risk factors were assessed by chi 2 and Fisher's exact tests. The seroprevalence of HCV was 34.2% with a significant difference between blood and sexual exposure risk groups (60.6% vs. 13.6%, respectively; P < 0.0001). Thirty-six of the 55 anti-HCV-positive sera were also positive for HCV RNA, and PCR detected HCV RNA in 8 HCV-seronegative patients. Various RIBA profiles were found and all sera were positive for antibodies to the c33 protein. A proportion of sera had elevated levels of transaminase activity (37.2%), and abnormal liver function as associated with HCV infection. Forty-two samples were genotyped and five genotypes and subtypes of the HCV virus were detected. Genotype 1a was the most frequent in this cohort, although genotype 1b is generally more common in France. The majority (94.1%) of the patients with genotype 1a had a history of blood exposure, which may account for the difference.

Hepatitis C genotypes in liver transplant recipients: distribution and 1-year follow-up

Chronic hepatitis C infection (CH-C) accounts for a significant number of patients undergoing orthotopic liver transplantation (OLT). Recently, hepatitis C virus (HCV) genotype-dependent differences in disease outcome and therapeutic responses have been suggested. The objectives of our study were to determine (1) the recurrence of HCV infection after OLT; (2) distribution of HCV genotypes in patients with CH-C who required liver transplantation compared with those who did not; and (3) the 1-year transplantation outcome in patients infected with different hepatitis C genotypes. RNA was extracted from sera of 20 patients who underwent OLT for end-stage liver disease secondary to CH-C (group I) and 52 patients with CH-C who did not require OLT (group II). For viral RNA detection, reverse transcriptase and polymerase chain reaction (RT/PCR) of 5'UT region was performed on all OLT patients both before and after OLT. For genotyping, RT-PCR of the NS 5 region was performed, followed by automated sequencing of the amplification products. Nineteen OLT patients had viral RNA detected by PCR both before and after OLT. One patient had no RNA detected before OLT but became viremic after OLT. The prevalence of HCV genotype 1b was significantly higher in group I patients compared with group II (53% v 23% respectively, P = .01). Examination of outcome at 1 year after OLT showed that 9 of 10 patients with HCV genotype 1b had histological evidence of hepatitis compared with 4 of 9 patients with other genotypes (non-1b) (P = .06). However, the number of patients who had one or more episodes of rejection, underwent retransplantation, or died at 1 year after OLT were similar. Recurrence of HCV infection after OLT was shown in all studied patients. Hepatitis C genotype 1b is more prevalent in our patients who underwent transplantation compared with a group with chronic hepatitis C who did not require transplantation (P = .01). Patients infected with HCV genotype 1b may have a higher risk of histological hepatitis after transplantation.

Hepatitis C virus genotypes in patients with chronic liver disease and haemodialysis patients from Saudi Arabia

The genotypes of hepatitis C virus (HCV) were investigated in 28 Saudi patients (21 males, seven females; age range 23-68 years; mean 45.0 years) with histologically proven chronic hepatitis (13 chronic active hepatitis and 15 liver cirrhosis) and in 32 Saudi patients with chronic renal failure maintained on haemodialysis (22 males, 10 females; age range 18-60 years; mean 40.0 years) who also had liver disease due to HCV. Among the 28 patients with chronic liver disease genotype 4 was the predominant one (60.7%), followed by types 1b (21.4%), 1a (14.3%) and 2a (3.6%). The distribution of genotypes was similar in patients with chronic active hepatitis to those with liver cirrhosis. Among the 32 patients with chronic renal failure and maintained on haemodialysis, genotype 4 was also the dominant type (55.0%), followed by 1a (25.0%), 1b (21.9%) and 2a (3.1%). In all categories studied the prevalence of genotypes between males and females was the same. As our patients were selected from various regions of Saudi Arabia, we believe that genotype 4 is the predominant one throughout the whole kingdom.

Persistent hepatitis C virus RNA replication in haemophiliacs: role of co-infection with human immunodeficiency virus

In order to evaluate the evolution of transfusional hepatitis C in haemophiliacs, we performed a retrospective study of ALT levels and HCV viraemia with a RNA PCR assay in 57 patients. We found that the vast majority of HCV-infected patients remained viraemic (43/57 = 75%) and higher ALT levels correlated with HCV viraemia. Although indicators of the transfusional viral load (age, severity of haemophilia) and HBV co-infection did not correlate with HCV RNA replication, HIV seropositivity was strongly associated with persistence of HCV viraemia (23/25 = 92% in HIV-positive versus 20/32 = 62% in HIV-negative patients), without any correlation with CD4 counts. Genotyping of HCV in the 43 viraemic patients shows more frequent genotype 1 in the HIV-seropositive group (14/23) than in the seronegative group (6/20). Our data emphasize that besides the role of the immunodeficiency status, the genotypes of HCV might be involved in the differences observed in terms of HCV RNA replication between the HIV-seropositive and seronegative haemophiliacs.

Evaluation of complete genome sequences and sequences of individual gene products for the classification of hepatitis C viruses

Comparisons of genome and polyprotein sequences of hepatitis C virus (HCV) isolates world-wide has led to the identification of nine major genotypes and many subtypes. This classification is based on either complete genome/polyprotein sequences or sequence data from the 5' noncoding region, core, E1, NS3 or NS5B genes. The relative merit of different gene segments as taxonomic markers and the validity of the resulting assignments is not clear at this stage. To resolve the taxonomy of HCV genotypes and subtypes, we have compared the complete genome and polyprotein sequences of 19 HCV isolates available in the databases as well as sequences of individual genes and gene products of these isolates. Based on the correlation between sequence relationships and taxonomic assignments of other RNA viruses, we show that the nine major genotypes of HCV represent nine distinct virus species and their subtypes subspecies. Our sequence comparison of the 5' noncoding regions and the individual gene products suggests that E2, NS2, NS5B, E1, NS4A, NS4B and NS5A (in that order) are the most appropriate regions for the discrimination between species, subspecies and strains of HCV. The 5' noncoding, core and NS3 regions are less effective in distinguishing between species, subspecies and strains. Based on a comparison of the polymerase sequence identities of HCVs, pestiviruses and flaviviruses as well as the recent information on the size and morphology of HCV virions, we propose that HCVs, pestiviruses and flaviviruses should be classified into three separate families, named Hepciviridae, Pestiviridae and Flaviviridae, respectively rather than three genera of the Flaviviridae as currently classified. We also propose "Hepcivirus" as the genus name for HCVs.

Clinical relevance of mutations in the precore genome of the hepatitis B virus

A stop codon in the precore genome of the hepatitis B virus (HBV) in anti-HBe positive HBV carriers may be associated with a more progressive form of HBV infection. Earlier studies, however, were mainly performed in patients from the Mediterranean area who had severe infection. The aim of this study was to evaluate the prevalence of precore mutants in an unselected population living in northern Europe. Twenty of 42 of these patients are infected predominantly with a virus strain, which has the typical stop codon in the precore genome, characterised by a mutation at base 83. In six patients there was an additional G to A mutation at base 86 of the precore genome. Statistical analysis showed no difference between the patients with or without a stop codon in the precore genome. When patients with a double mutation at base 83 and 86 of the precore genome were compared with the other anti-HBe positive HBV carriers, however, the corresponding clinical data were worse. Therefore we suggest, that it is not the stop codon in the precore gene itself, but the occurrence of a double mutation at bases 83 and 86, which is associated with a more severe course of disease in anti-HBe positive HBV carriers.

Hepatitis C virus genotyping by means of 5'-UR/core line probe assays and molecular analysis of untypeable samples

To test the theoretical possibility of 5'-UR mistyping between hepatitis C virus subtypes 1a and 1b, we combined a 5'-UR/Core line probe assay (LiPA) with a nested PCR system and retested 183 sera, previously genotyped as type 1a or 1b and originating mainly from Western Europe. Eight percent of these were found to be wrongly subtyped. Based on this method, 3 additional subtypes of type 1 were discovered (1d-1f). Randomly selected European type 2 sera (n = 18) were tested with a similar type 2 5'-UR/Core LiPA. They were unexpectedly found to belong to subtype 2c in the majority of cases. Among serum samples originating from South-East Asia, several additional genotypes (7a, 7c, 7d, and 9a) were detected which had 5'-UR sequence motifs indistinguishable from genotype 1. Based on 13,203 pairwise comparisons in the 340-bp NS5B region, classification into types, subtypes, and isolates was obtained in 99.8% of all cases by using the phylogenetic border value of 0.328 for subtypes/types and 0.127 for isolates/subtypes; and evidence for a 10th major type of HCV was provided. Combination of all available HCV sequence data from the 447-bp Core/E1 region and the NS5B 340-bp and 222-bp regions provided evidence for the existence of 10 types, including 50 subtypes. Previously, extensive studies involving genotypes 1a, 1b, 2a, and 2b indicated the importance of HCV subtyping in interferon treatment and progression of chronic liver disease. The herein described expansion in the number of HCV types and subtypes should help improve diagnosis, treatment and possibly prophylaxis of hepatitis C liver disease.

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

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

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

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

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

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

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

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

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

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

Hepatitis C virus genotypes in Belgian hemophiliacs

Hemophiliacs who have been exposed to unheated and/or dry heated pooled clotting factor concentrates are at a high risk of chronic hepatitis C. Serum HCV-RNA was measured by reverse transcriptase-polymerase chain reaction (RT-PCR) technique in 58 hemophiliacs positive for anti-HCV antibodies, HCV-RNA was detected in 55 patients. Based on the results of PCR positivity, HCV genotyping was carried out using genotype specific probes and the dot blot hybridization assay: 2 patients were found to be infected with type 1a (3.6%), 31 patients with type 1b (56.4%), 8 patients with type 2 (14.6%), 6 patients with type 3 (10.9%), 1 patient with type 4, and 7 patients with double infection (12.7%). As compared to a control group of 105 nonhemophilia patients with chronic hepatitis C, HCV genotype 1b was found predominant in both groups. However, double infection with two HCV types as well as a relatively high prevalence of infection with type 2 and type 3 were found in hemophiliacs.

Expression and processing of putative nonstructural proteins of hepatitis C virus in insect cells using baculovirus vector

Processing of the putative nonstructural (NS) proteins, p70(NS3), p4(NS4A), p27(NS4B), p58/56(NS5A), and p66(NS5B), of Japanese type hepatitis C virus (HCV) in insect cells was analyzed by using a baculovirus expression system. Products processed by the HCV serine proteinase (Cpro-2) were essentially identical to those found in mammalian cultured cells transiently producing the NS region of the HCV precursor polyprotein. A series of internal and carboxy (C)-terminal deletion experiments coupled with epitope scanning analysis showed that efficient cleavage at the Cpro-2-dependent processing sites, except at the p4(NS4A)/p27(NS4B) site, is not significantly influenced by those mutations. Efficient cleavage at p4(NS4A)/p27(NS4B) required about 40% of the NS5A N-terminal region. Estimation of the processing sites by determination of the N-terminal amino acid sequences of the processed products revealed that all the Cpro-2-dependent cleavages occurred at essentially identical sites to those reported for another HCV genotype, suggesting that Cpro-2 is a possible target for the development of a strain-independent anti-HCV agent.

Serological reactivity and viral genotypes in hepatitis C virus infection

Patients infected with hepatitis C virus (HCV) were examined with four commercial HCV immunoblotting assays and for anti-GOR antibody to ascertain whether serological findings varied with the genotype of the infecting virus. The results indicate that patients infected with different HCV genotypes tend to show different immunoblotting profiles, mainly due to a low prevalence of antibodies to the viral region NS4 in patients infected with genotypes III and IV. Differences were more evident with second- than with third-generation assays. Patients infected with genotype IV exhibited a lower prevalence of anti-GOR antibody than patients infected with other genotypes.

Prevalence and determinants of anti-HCV seropositivity and of HCV genotype among intravenous drug users in Berlin

A cross-sectional study was carried out to identify risk factors for seropositivity for antibodies against hepatitis C virus (HCV) and to assess to the distribution and determinants of HCV genotypes among intravenous drug users (IVDUs). The study population consisted of 405 IVDUs. Serum specimens were tested for seromarkers for HCV, for human immunodeficiency virus (HIV), for hepatitis B virus (HBV) and for syphilis. HCV RNA determination by polymerase chain reaction (PCR) and virus typing were performed in a subsample of anti-HCV-positive specimens (n=135). Of the IVDUs, 83% were anti-HCV-positive, 18% HIV-infected, and 58% HBV (anti-HBc)-positive. Longer duration of intravenous drug use, syringe sharing in prison, and higher number of IDVU sex partners were independent risk factors for anti-HCV positivity. GCV RNA was detected in 76% of anti-HCV-positive IVDUs. HCV genotypes 1 (49%) and 3 (44%) were most commonly found. All the type 3 isolates were identified as subtype 3a, and 95% of the type 1 isolates as subtype 1b. In logistic regression analysis, HCV type 3a viraemia was significantly associated with lack of HIV infection and a higher number of sex partners. The results indicate that preventive measures are needed to reduce syringe sharing among IVDUs in prisons. Sexual contacts with other IVDUs may play a role in the HCV epidemic among IVDUs. In Germany, HCV type 3a infection appears to be much more common among IVDUs than among other HCV risk groups such as transfusion recipients or haemophiliacs.

Distribution of three major hepatitis C virus genotypes in Italy. A multicentre study of 495 patients with chronic hepatitis C

Different genotypes of hepatitis C virus (HCV) have been shown to have distinct geographical distribution and to associate with variable clinical features. To evaluate their role in chronic hepatitis in Italian patients, we studied 495 consecutive cases with chronic hepatitis C seen in nine sentinel centres homogeneously distributed over Italy. HCV genotyping was carried out using a dot-blot hybridization assay with genotype-specific probes. Four hundred and eleven patients were viraemic and could be evaluated: 57% were found to be infected with HCV-1, 31% with HCV-2, 8% with HCV-3, 1% showed mixed infection and 3% were ascribed to HCV-2b or HCV-4 by direct sequencing. Geographical distribution showed discrete territorial variations. A history of drug addiction was commoner in patients infected with HCV-3. There were no significant differences in activity of liver disease among different HCV genotypes but the response to interferon therapy was reduced in patients infected with HCV-1 compared to HCV-2 or HCV-3.

Viral hepatitis. Current concepts for dental practice

The transmission of blood-borne viruses in the dental office is a potential hazard to patients and dental staff, particularly to oral and maxillofacial surgeons. Hepatitis B virus has been a recognized hazard for several years, and in the past oral surgeons and other dental health care staff have been infected as a result of occupational exposure. Hepatitis C virus in contrast does not appear to be a major occupational hazard to dental staff, nevertheless, infection with this virus can lead to significant morbidity and may have oral manifestations. Hepatitis D virus can be nosocomally transmitted, but vaccination against the hepatitis B virus minimizes this problem. Hepatitis E virus is not of clinical relevance to dentistry, although dental staff who are in areas of endemic infection can become infected as a result of enteric transmission. A number of other putative viral agents may also cause hepatitis, but additional data is awaited, and their significance to dental practice is unknown. This article summarizes current data on hepatitis viruses A, B, C, D, and E.

Subtype analysis of hepatitis C virus in Indonesia on the basis of NS5b region sequences

A recently identified subtype of hepatitis C virus, subtype 1d, was found to be common in Indonesia, being isolated from 4 (20%) of 20 and 11 (34%) of 32 patients with chronic hepatitis and liver cirrhosis, respectively. A new group of sequence variants was also identified, although its prevalence ratio was not as high in the area surveyed.

Histologic activity of the liver in children with transfusion-associated chronic hepatitis C

Adults with chronic hepatitis C develop cirrhosis over a period of 6 to 20 years, but there are few reports of this disorder in children. To determine the histologic activity of chronic hepatitis C in children, we examined 31 biopsy specimens from 25 children (age range 3-16 years) with this disease. All patients were seropositive for antibody to hepatitis C virus by second-generation testing, and for HCV-RNA by the polymerase chain reaction. All cases were transfusion-associated. Patients were divided into two groups according to underlying disease: malignant disease or aplastic anemia (Group A, 17 cases) and non-malignant disease (Group B, eight cases). All patients in Group A, but only one in Group B, had received multiple transfusions. All patients in Group A had received intensive courses of cytotoxic and immunosuppressive agents. The histologic diagnosis was made using the standard criteria and Knodell's histology activity index. Chronic persistent hepatitis was more common in Group B (six patients) than in Group A (three patients). Chronic aggressive hepatitis 2B was found only in Group A (five patients). The mean histology activity index score was higher in Group A than in Group B (8.5 vs. 5.7). Six patients (four in Group A and two in group B) subsequently had a liver biopsy. The pathological diagnosis did not change after the second biopsy in any patient in Group B, while two patients in Group A showed a rapid progression of hepatitis. In each category of the histology activity index, periportal necrosis and intralobular necrosis were more severe in Group A than in Group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus infection in patients with chronic liver disease or chronic renal failure and blood donors in Thailand

Hepatitis C virus (HCV) RNA and genotypes, as well as markers of hepatitis B virus infection, were surveyed in 171 patients with chronic liver disease, 276 patients with chronic renal failure, and 961 blood donors in Thailand. HCV RNA was detected in 30 (23%) of 128 patients with non-alcoholic chronic liver disease and hepatitis B surface antigen (HBsAg) in 60 (47%), and both HCV RNA and HBsAg in 3; the cause of liver disease was not established in 41 (32%) patients. HCV RNA was detected in 44 (20%) of 221 patients on maintenance hemodialysis or with kidney transplantation, but in none of 55 patients on peritoneal dialysis. Antibodies to synthetic HCV core peptides were detected in 39 (4.1%) of sera from 961 blood donors, and HCV RNA was detected in 8 (0.8%). Of the 90 HCV RNA samples from patients and donors, genotype V prevailed (46%) followed by II (22%), I (14%), III (3%), and VI (2%); genotypes were not classifiable into any of I-VI in the remaining 10%. There were six sera which contained HCV RNA, but were without antibody to HCV detectable by the second-generation enzyme immunoassay. HCV RNA titers were high in four patients with kidney transplantation, but low in one patient with chronic liver disease and one patient on maintenance hemodialysis. HCV RNA at high titer (> or = 10(4)/ml) was not classifiable in one patient. These results indicate HCV of novel genotypes in Thailand, seronegative HCV infection in patients with kidney transplantation, and a low risk of HCV infection in patients treated by peritoneal dialysis.

Hepatitis C virus and its genotypes in patients suffering from chronic hepatitis C with or without a cryoglobulinemia-related syndrome

Recently, evidence has been presented for a possible association between hepatitis C virus (HCV) infection and essential mixed cryoglobulinemia (EMC). Eleven consecutive patients with EMC and two with cryoglobulinemia type I were examined for the presence of markers of HCV infection. Eleven of 13 patients (10 with EMC and 1 with type I cryoglobulinemia) had anti-HCV antibodies (as determined by a second generation anti-HCV assay) and HCV-RNA in plasma or serum. HCV-RNA was also detected in liver biopsies of five patients. Genotyping showed that HCV genotype 1 was found in 10 of 11 patients with HCV-RNA (9 genotype 1b and 1 genotype 1a) and only one patient had HCV genotype 2. However, a similar high prevalence of genotype 1b (100%) was found in a group of 14 consecutive patients with chronic hepatitis C, who had no clinical evidence of cryoglobulinemia. Concomitant infection was present in three patients with genotypes 2, 3 and 4, respectively. These findings stress the high prevalence of HCV infection in patients with EMC and further study shows that a difference in genotype prevalence was not found between HCV-related EMC and chronic hepatitis C without clinical manifestations of EMC.

Hepatitis C virus RNA and antibodies among blood donors in Beijing

Blood units from voluntary as well as commercial donors in Beijing, China, were tested for hepatitis C virus RNA and antibodies, and for serological markers of hepatitis B virus infection. HCV RNA was detected less frequently in 1909 voluntary donors (5 (0.3%)), than in 1017 commercial donors (58 (5.7%)) (p < 0.001). Antibody to hepatitis C virus was detected by the second-generation enzyme immunoassay in 55 (87%) of 63 blood units with viremia. Evidence of present or past infection with hepatitis B virus was common both in voluntary (43.9%) and commercial (46.4%) donors. There were eight (13%) sera with HCV-RNA in which hepatitis C virus antibodies were not detectable by second-generation enzyme immunoassay. Of 63 HCV-RNA samples from donors, 33 (52%) were of genotype II, 18 (29%) of III and one (2%) of II + III. HCV-RNA in the remaining 11 (17%) were not classifiable into any of the genotypes I, II, III, IV and V. Genotype II was more frequent in viremic donors with elevated alanine aminotransferase levels (13/18 or 72%) than in those with normal levels (20/45 or 44%). These results indicate a low prevalence of hepatitis C virus infection in the general population in Beijing, and the limitations of identifying sera with viremia by second-generation enzyme immunoassay.

Analysis of hepatitis C virus isolates among healthy blood donors and drug addicts in Chiang Mai, Thailand

Hepatitis C virus (HCV) isolates obtained from 25 anti-HCV antibody-positive healthy blood donors and 29 drug addicts in Chiang Mai, Thailand, were analyzed. HCV RNA was detected in 23 blood donor samples (92%) and 24 drug addict blood samples (83%) by PCR for a portion of the NS5 region. Subtype analysis revealed that HCV type 3a (HCV-3a) was the prevailing subtype (30%), which was followed in prevalence by HCV-1a (21%), -1b (13%), -3b (13%), and -6a (2%). Six (13%) of the 47 isolates showed low sequence similarities with known types and subtypes. The sequence variants could be grouped into four branches in a molecular evolutionary phylogenetic tree.