Molecular biology of the hepatitis C viruses: implications for diagnosis, development and control of viral disease

Pretreatment serum hepatitis C virus RNA levels and hepatitis C virus genotype are the main and independent prognostic factors of sustained response to interferon alfa therapy in chronic hepatitis C

The aim of the study was to determine the respective influence of pretreatment serum hepatitis C virus (HCV) RNA levels and HCV genotype on the response to interferon (IFN) alfa in patients with chronic hepatitis C. We retrospectively studied 141 patients with chronic hepatitis C included in two consecutive controlled trials of IFN alfa. A sustained response was observed in 28, a response followed by relapse in 43, and no response in 70 patients. Pretreatment serum HCV RNA quantitation with the branched DNA (bDNA) assay and HCV genotyping with reverse hybridization assay (LiPA) were performed in all patients. Seventy-four percent of the patients had detectable serum HCV RNA (43%, 77% and 84%) in the three groups of patients with sustained response, relapse, and no response, respectively (P = .005). Mean serum HCV RNA level were 1.4 +/- 6 x 10(6), 4.8 +/- 6 x 10(6), and 3.9 +/- 5 x 10(6) genomes/mL in patients with sustained response, response and relapse, and no response, respectively (P < .01). Genotype 1b was found in 7%, 47%, and 46% of the patients in the three response groups, respectively. By univariate analysis, age, source, and duration of HCV infection, serum HCV RNA levels, and HCV genotypes were significantly different in the three response groups. By multivariate analysis, the only independent factors associated with sustained response were low serum HCV RNA levels and HCV genotype other than 1b. Pretreatment serum HCV RNA levels and HCV genotype are the main and independent factors associated with sustained response to IFN therapy.

Sequence analysis of the hepatitis C virus (HCV) core gene suggests the core protein as an appropriate target for HCV vaccine strategies

Hepatitis C virus (HCV) is a major healthproblem with a prevalence of 1% in the United States population, and a significant percentage of infected patients progress to chronic liver disease and cirrhosis. Interferon therapy has demonstrated that the immune system can be modulated to alter the acute course of the disease, but long-term treatments remain elusive. Prevention of hepatitis C infection is therefore an important strategy to mitigate the impact of this disease. Initial attempts at vaccination have focused on recombinant envelope vaccines, which have shown an ability to protect against very low titre challenges of HCV in chimps. The need for vaccines capable of protecting against higher titre challenges has led to the search for alternative vaccine strategies. The most highly conserved structural protein in the HCV genome is the core protein, and vaccine strategies targeting the core protein have been proposed to increase vaccine efficacy. The variability of HCV core sequences and genotypes in the Ann Arbor patient population are not known, and the present study was undertaken to assess the theoretical feasibility of developing a HCV core vaccine by excluding promiscuous core (C) gene variability as a mechanism of vaccine failure. Results of nucleotide and deduced amino acid sequence analysis from 13 of 14 patients studied reveal a 93% nucleotide and 96.4% amino acid core sequence homology in the C gene regions studied. Genotype analysis revealed four of 14 to be type 1a and nine of 14 to be type 1b with one infection not being sufficiently characterized to determine genotype. These results demonstrate a sufficiently high degree of conservation of HCV core sequences in our patient population to permit design of a vaccine directed against core protein.

Detection of hepatitis C virus RNA by a reliable, optimized single-step reverse transcription polymerase chain reaction

A single-step reverse transcription polymerase chain reaction (SRT-PCR) method was optimized for hepatitis C virus (HCV) RNA detection. Extraction procedures by proteinase K and guanidinium isothiocyanate gave similar results. The optimal MgCl2 concentration for the SRT-PCR method was 2 mM with 10 units of superscript M-MLV RNase H-reverse transcriptase and 1 unit of Taq polymerase. Shorter PCR cycling steps gave a 10-fold-increased PCR product compared with longer cycling steps. Twenty-five anti-HCV-positive sera from chronic hepatitis C patients were positive with SRT-PCR, whereas only 17 out of 25 were positive by dissociated RT and PCR (dRT/PCR). Specificity was assessed by twenty negative controls. SRT-PCR was 5-fold more sensitive (5 HCV RNA copies per assay) than dRT/PCR with an HCV RNA transcript. Our SRT-PCR method for HCV RNA detection appears fully adapted for routine use in a medical virology laboratory.

Immune responses to plasmid DNA encoding the hepatitis C virus core protein

Hepatitis C virus (HCV) is a major causative agent of parenterally transmitted non-A, non-B hepatitis. The genomic region encoding the virion-associated core protein is relatively conserved among HCV strains. To generate a DNA vaccine capable of expressing the HCV core protein, the genomic region encoding amino acid residues 1 to 191 of the HCV-1 strain was amplified and cloned into an eukaryotic expression vector. Intramuscular inoculation of recombinant plasmid DNA into BALB/c mice (H-2d) generated core-specific antibody responses, lymphoproliferative responses, and cytotoxic T-lymphocyte activity. Our results suggest that the HCV core polynucleotide warrants further investigation as a potential vaccine against HCV infection.

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

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

Fraction-specific populations of the hypervariable region of the hepatitis C virus in a patient with cryoglobulinemia

Nucleotide sequences of the hypervariable region (HVR) of the E2/NS1 gene of hepatitis C virus (HCV), which are now thought to contain epitopes for neutralizing antibodies, were compared between antibody-bound HCV and free HCV in a patient with type II cryoglobulinemia. Antibody-bound HCV was immunoprecipitated with anti-human immunoglobulins from serum of the patient. Total RNA was recovered from the pellet and the supernatant, respectively, and the envelope gene containing the HVR was amplified by the reverse transcription and nested polymerase chain reaction. The amplified cDNA was examined by the single strand conformation polymorphism (SSCP) analysis. Sequences of bands separated by SSCP analysis were determined by the dideoxy chain termination method. SSCP analyses revealed that the HCV populations were completely different between antibody-bound HCV and free HCV: antibody-bound HCV was composed of two bands and free HCV was composed of three bands. These five bands showed different mobility with each other on the SSCP gel. Sequencing of each band revealed distinct HVR sequences, differing in 1-34 nucleotides and 1-15 deduced amino acids. Three sequences of free HCV was similar with each other (1-5 nucleotide and 1-4 amino acid differences). On the other hand, two sequences of antibody-bound HCV had 5-34 nucleotide and 5-15 amino acid differences with free HCV. Thirteen amino acids in the 5' of HVR were completely identical in three sequences of free HCV, whereas there were three and seven amino acid differences in two sequences of antibody-bound HCV. These findings suggest that isolated specific epitopes for envelope antibodies exist within the HVR.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and virological findings in mixed cryoglobulinaemia

OBJECTIVES

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

DESIGN

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

SUBJECTS

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

RESULTS

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

CONCLUSIONS

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

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

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

Preclinical evaluation of AMPLICOR hepatitis C virus test for detection of hepatitis C virus RNA

We compared a single-enzyme, combined reverse transcription-PCR (RT-PCR; AMPLICOR HCV Test; Roche Molecular Systems, Branchburg, N.J.) with an independent, two-enzyme, standard RT-PCR (SRT-PCR) assay for the detection of hepatitis C virus (HCV) RNA in serum and plasma. Test samples included a proficiency testing panel consisting of 10 undiluted plasma samples, three separate dilution series, and sera from 99 patients with chronic liver disease. The quantity of HCV RNA in each patient serum sample was determined by a branched DNA (bDNA) signal amplification assay (Quantiplex HCV-RNA assay; Chiron, Emeryville, Calif.). There was complete concordance between the results of the RT-PCR assays with the 10 undiluted plasma samples used for proficiency testing (3 positive and 7 negative samples). However, the analytical sensitivity of SRT-PCR was 4- to 10-fold greater than that of the AMPLICOR test in the dilution series. HCV RNA was detected in 44, 45, and 40 of the patient serum samples, by SRT-PCR, the AMPLICOR test, and the bDNA assay, respectively. There was 97% agreement between the results of the RT-PCR assays, with only three discrepancies. Review of the patients' medical records resolved all three discrepancies in favor of the AMPLICOR results (two false-negative SRT-PCR results and one false-positive SRT-PCR result). The quantity of HCV RNA in sera from five (11%) patients with viremia detected by AMPLICOR was below the bDNA assay cutoff (< 3.5 x 10(5) RNA equivalents per ml). AMPLICOR compared favorably with SRT-PCR, with key advantages of speed, ease of use, increased sample throughput, and protection against false-positive results because of amplicon carryover.

High prevalence of hepatitis B, C, and E markers in young sexually active adults from the Central African Republic

The Central African Republic is located in tropical Africa, where both the human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are highly endemic. The exact prevalence of hepatitis C virus (HCV) and hepatitis E virus (HEV) markers in this country is unknown. The aim of the study was to determine, according to HIV and HBV serostatus, the prevalence of these markers in young sexually active adults in the Central African Republic. One hundred and fifty-seven consecutive patients attending the National Centre for Sexually Transmitted Diseases in Bangui were included. The following serological markers were examined: (i) anti-HIV1 and anti-HIV2 antibodies; (ii) markers of HBV infection; (iii) anti-HCV antibodies; (iv) anti-HEV antibodies. Anti-HIV1 antibodies were found in 31 of the 157 patients (20%). The prevalence of anti-HBc antibodies, reflecting exposure to HBV, was 140/157 (89%) and 45 had detectable anti-HBs antibodies. Twenty-two patients (14%) were chronic carriers of hepatitis B surface antigen (HBsAg), but only one was HBe antigen-positive. Anti-HCV antibodies were found in 8 persons (5%) and anti-HEV antibodies in 38 (24%). No difference was found in the prevalence of these markers according to the presence or absence of anti-HIV antibodies. This study confirms the high rate of HIV infection, HBV exposure and chronic carriage of HBsAg in sexually active young adults in the Central African Republic. A high prevalence of HCV markers was found in this population, similar to that reported in neighbouring countries, together with a high rate of HEV markers, suggesting that HEV is endemic in this region.

Single-step reverse transcription-polymerase chain reaction for hepatitis C virus RNA with DNA enzyme immunoassay hybridization

A single reverse transcription-polymerase chain reaction (SRT-PCR) for HCV RNA detection, confirmed by hybridization of amplified products with biotinylated probes using DNA enzyme immunoassay (DEIA), was compared to nested-PCR (N-PCR) on 20 sera from patients with chronic (n = 18) or acute (n = 2) hepatitis. Results obtained by SRT-PCR confirmed by DEIA and by N-PCR identical. All but one of the patients with chronic hepatitis and positive HCV serology as well as the patients with acute hepatitis had detectable HCV RNA in serum; all patients with chronic hepatitis and indeterminate HCV serology and all controls (n = 5) were negative by the two PCR methods. Both SRT-PCR and N-PCR remained positive after 7 x 10(-2) and 5 x 10(-4) dilutions of two HCV RNA-positive sera. The threshold of detection for SRT-PCR was 15 RNA copies per assay, as assessed by testing serial dilutions of an in vitro synthesized 5'-NCR HCV RNA transcript. SRT-PCR confirmed by DEIA for HCV RNA appears to be as sensitive and specific as N-PCR. Furthermore, it is easier to perform, with less of contamination, is less time-consuming, requires fewer enzymes, and it permits semi-quantification of PCR products.

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

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

Rapid genotyping of hepatitis C virus isolates by dideoxy fingerprinting

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

Genotype-dependent serologic reactivities in patients infected with hepatitis C virus in the United States

OBJECTIVE

To evaluate the serologic reactivities in patients infected with different hepatitis C virus (HCV) genotypes to four HCV proteins that are components of the second-generation recombinant immunoblot assay.

MATERIAL AND METHODS

Serum samples from 36 patients with chronic HCV infection were obtained. RNA was extracted by using chaotropic lysis and isopropanol precipitation. Reverse-transcriptase polymerase chain reaction of the NS-5 region was performed, followed by automated single-pass dideoxy sequencing of desalted amplification products. Classification of isolated HCV subtypes was based on Simmonds' system. All samples were tested for antibodies to proteins 5-1-1, C100-3, C33c, and C22-3 with the second-generation recombinant immunoblot assay.

RESULTS

Reactivity to protein 5-1-1 was significantly lower for patients with genotypes 2b and 3a than for those infected with HCV types 1a or 1b (P < 0.05). Antibody reactivity to the C100-3 protein was also reduced in patients infected with HCV types 2b and 3a.

CONCLUSION

These data indicate that the genotype-dependent differences in serologic reactivities are substantial among patients with chronic HCV infection.

Classification of hepatitis C virus into major types and subtypes based on molecular evolutionary analysis

Molecular evolutionary analysis was applied to determine the number of hepatitis C virus (HCV) types and subtypes based on all the HCV nucleotide sequences available from the DNA data banks (DDBJ, GenBank (NCBI), EMBL) and the literature. There was an excellent concordance among the types and subtypes assigned based on different HCV genomic regions. Only one HCV isolate was assigned to different HCV types based on the 5' non-coding (NC) and envelope 1 (E1) regions. The 5' NC region was well conserved and could be used to assign only types and not subtypes. From the sequence data available there were 13 subtypes based on the core region and 14 subtypes based on the E1 and non-structural protein 5 (NS5) regions.

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

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

Hepatitis C virus genotypes in French blood donors

The prevalence of different hepatitis C virus (HCV) genotypes in HCV infected individuals and the relation between the HCV genotypes and the source of the infection are controversial. The aim of this study was to determine the HCV genotypes in French blood donors. Fifty-one anti-HCV positive blood donors were studied with detectable serum HCV RNA by nested polymerase chain reaction (PCR) using primers derived from the 5' non-coding region. For genotyping HCV, we used a method based on analysis of the restriction fragment length polymorphisms (RFLP) after amplification by PCR of the HCV non-structural 5 (NS5) genome domain. Using this technique, the genotypes of 39 of the 51 blood donors (76%) were determined. Three previously described genotypes were found: 19 blood donors were infected by HCV genotype I (37%), 14 were infected by HCV genotype II (27%), 3 were infected by HCV genotype III (6%), and 3 were coinfected by two genotypes (6%). All three blood donors infected with two different genotypes were intravenous drug abusers. A past history of intravenous drug abuse was more frequent in blood donors with HCV genotype I. However, there was no difference in alanine transaminase (ALT) levels, histological lesions, and RIBA-2 patterns in blood donors infected with either HCV genotype I or HCV genotype II. These findings indicate that most HCV genotypes isolated from French blood donors belong to HCV genotype I and HCV genotype II, and that risk factors for HCV infection may differ for different genotypes of HCV.

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

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

Classifying hepatitis C virus genotypes

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

Antibody to hepatitis C virus second envelope (HCV-E2) glycoprotein: a new marker of HCV infection closely associated with viremia

The second envelope protein (E2) of the hepatitis C virus (HCV) was cloned and expressed in Chinese hamster ovary (CHO) cells. This E2 glycoprotein was purified using ion exchange and lectin chromatography and used to construct an enzyme immunoassay for HCV E2 antibodies. The assay was shown to have good specificity, and detection of E2 antibodies was positively correlated (97.3%) to the presence of HCV RNA in serum and plasma. A high concordance between HCV 2.0 and E2 EIA reactivities was also observed. E2 antibody was the first serological marker to appear in 3/5 HCV seroconversion panels. This work demonstrated that 42.4% of core and 15.4% of NS3 indeterminate specimens also contained antibodies to E2, suggesting that HCV infection had occurred in these individuals. The E2 antibody assay was used to evaluate HCV 2.0 EIA-positive, HCV 3.0 EIA-negative plasma donors with indeterminate reactivity on RIBA HCV 2.0 or MATRIX HCV 1.0. Several HCV 3.0-negative specimens were shown to contain E2 antibodies in addition to an original indeterminate serological marker, primarily core. It is concluded that anti-E2 is a useful marker for determining HCV infection, and that the presence of antibodies to two nonoverlapping viral gene products suggests true HCV exposure. New HCV 3.0 blood screening tests should detect HCV 2.0-positive donors who present with an indeterminate pattern by RIBA or MATRIX and who also carry E2 antibodies.

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).

Hepatitis C virus serum markers and liver disease in children with leukemia

This review summarises serologic profiles and clinical features of HCV infection in children with leukemia. The diagnosis of HCV infection is currently based on the detection in serum of antiviral antibodies and HCV-RNA. Studies on leukemic children, however, have clearly shown that only HCV-RNA testing correctly identifies HCV infection, as specific antibodies become detectable in serum only after chemotherapy withdrawal in almost all cases. Viraemia instead appears early in the course of leukemia, and infected patients become carriers. The pattern of liver disease is rather homogeneous. Early onset, persisting ALT elevation during chemotherapy often with drastic reduction during high-dose chemotherapy, followed by sharp exacerbations of liver cell necrosis. ALT normalise after chemotherapy withdrawal in most cases, despite persisting viraemia. As regards to the ultimate prognosis of liver disease in these children, we have observed that, among a series of 119 patients followed for at least 10 years off-therapy, none has developed clinical decompensated liver disease and only 6% still has abnormal ALT levels. On the other hand, the need for prolonged follow-up of children surviving leukemia with chronic HCV infection is emphasized by the fact that the natural history of HCV infection has not been fully clarified and that additional late sequelae are likely to occur.

Lymphotropism of hepatitis B and C viruses: an update and a newcomer

The mechanisms of viral persistence are complex and include infection of the lymphoid cells. In the case of hepatitis B virus, early observations have suggested that HBV may infect peripheral blood mononuclear cells (PBMC). In animal models studies in chronic hepatitis B patients have further confirmed that viral DNA replicative intermediates, as well as viral transcripts and proteins, can be detected in PBMC under certain conditions. The consequences of this lymphotropism are not fully understood, but it seems likely that PBMC represent an extrahepatic reservoir of virus. The ability of hepatitis C virus to infect PBMC has been demonstrated in vivo and in vitro. The link between HCV lymphotropism and both the natural history of the viral infection and the immunological disorders frequently observed in HCV infections still needs to be established. In both cases, the infection of PBMC by HBV or HCV may represent the source of infection of the liver graft in patients transplanted for end-stage liver disease associated with HBV or HCV.

Hepatitis C genotypes in haemophilic patients treated with alpha-interferon

The effect of alpha-interferon on the hepatitis C genotypes was examined in 25 anti-HCV-positive haemophilic patients. The rate of multiple HCV genotypes in patients who are likely to have mixed infections was also studied. Pretreatment results showed that 3/25 (12%) patients had a change in genotypes, whereas posttreatment this rose to 10/25 (40%). Seven of 10 (70%) patients who showed a change in genotype had a clinical response to alpha-interferon. Six of 25 (24%) patients showed a complete clinical response to alpha-interferon, and the majority of these were either type 2 or 3. This study supports previous evidence that type 1 is less likely to respond to alpha-interferon, and that alpha-interferon may alter the concentrations of the various circulating genotypes present in multiply-infected patients. There are many difficulties in studying hepatitis C in haemophilic patients due to the sequence heterogeneity within each individual, and this study has shown that no ideal method exists as yet for looking at HCV genotypes in multiply-infected individuals.

The GCGGAA gene-regulatory motif of herpes simplex virus type-1 is also found in hepatitis C virus

We have analyzed the sequence of the 5'-untranslated region of hepatitis C virus from 24 patients with chronic hepatitis C and we found a conserved six-nucleotide motif previously described as a modulator of gene expression.

Quantification of hepatitis C virus RNA by competitive amplification of RNA from denatured serum and hybridization on microtiter plates

The direct detection of hepatitis C virus (HCV) RNA by PCR is widely used to determine the presence of circulating virions. The most relevant limit of this approach is the lack of quantitative information about the viral titer. We report a technique of competitive amplification allowing the estimation of HCV RNA copy number in biological samples. We constructed a standard competitive RNA template containing only two point mutations compared with its wild-type counterpart. The competitor was added in titrated amounts to the target RNA, and the mixture was then reverse transcribed and amplified in the same reaction tube. The relative amounts of target and competitor were determined by differential hybridization on microtiter plates with nonradioactive probes. The evaluation of HCV RNA titer required a single coamplification with the competitor and could be read from a standard curve. Furthermore, this method proved suitable for amplification of HCV RNA directly from serum, thus avoiding the intrinsic variability of the RNA extraction step.

Hepatitis C virus RNA detection and HCV genotype in patients with chronic non-A, non-B hepatitis in Jakarta

Antibody response in HCV infection may be variable and the variability of the serological response could be due to the differences in HCV strains. Since the distribution of hepatitis C virus genotype has been found to be geographically dependent, it is important to determine the distribution of HCV genotype in various countries with high prevalence of chronic non-A, non-B hepatitis. In this study, serum HCV RNA was examined in 53 patients suspected of chronic non-A, non-B hepatitis with an anti-HCV test as determined by currently available assay. HCV viremia was detected in 48 patients (90.6%). These patients had elevated serum ALT level at the time of HCV RNA determination. Using specific genotype probes, all isolates were classified into three different genotypes. Double and triple infections were also noted. HCV genotype 1b is the predominant genotype found in chronic hepatitis C patients in Jakarta.

Substrate determinants for cleavage in cis and in trans by the hepatitis C virus NS3 proteinase

Processing of the hepatitis C virus polyprotein is accomplished by a series of cotranslational and posttranslational cleavages mediated by host cell signalases and two virally encoded proteinases. Of these the NS3 proteinase is essential for processing at the NS3/4A, NS4A/4B, NS4B/5A, and NS5A/5B junctions. Processing between NS3 and NS4A occurs in cis, implying an intramolecular reaction mechanism, whereas cleavage at the other sites can also be mediated in trans. Sequence analysis of the amino termini of mature cleavage products and comparisons of amino acid residues around the scissile bonds of various hepatitis C virus isolates identified amino acid residues which might contribute to substrate specificity and processing efficiency: an acidic amino acid at the P6 position, a Thr or Cys at the P1 position, and a Ser or Ala at the P1' position. To study the importance of these residues for NS3-mediated cleavage we have undertaken a mutational analysis using an NS3'-5B polyprotein expressed by recombinant vaccinia viruses in mammalian cells. For all NS3-dependent cleavage sites P1 substitutions had the most drastic effects on cleavage efficiency, showing that amino acid residues at this position are the most critical substrate determinants. Since less drastic effects were found for substitutions at the P1' position, these residues appear to be less important for proper cleavage. For all cleavage sites the P6 acidic residue was dispensable, suggesting that it is not essential for substrate recognition and subsequent cleavage. Analysis of a series of mutations at the NS3/4A site revealed great flexibility for substitutions compared with more stringent requirements at the trans cleavage sites. On the basis of these results we propose a model in which processing in cis is determined primarily by polyprotein folding, whereas cleavage in trans is governed not only by the structure of the polyprotein but also by specific interactions between the proteinase and the polyprotein substrate at or around the scissile bond.

High efficiency prokaryotic expression and purification of a portion of the hepatitis C core protein and analysis of the immune response to recombinant protein in BALB/c mice

Hepatitis C virus (HCV) produces chronic persistent liver infection in 1-2% of the U.S. population and is the leading cause of end stage liver disease in patients presenting for liver transplantation at our center. Efforts to cure persistent HCV infection are frequently unsuccessful, so the development of a HCV vaccine is a high priority. HCV envelope proteins are hypervariable so production of a recombinant surface antigen vaccine such as is available for hepatitis B is not likely to confer widespread, high level protective immunity. As the most highly conserved structural protein in the HCV genome, the core protein is one reasonable target for vaccine production. Presented here are data on the manufacture of recombinant core protein containing partial carboxy terminus deletions in an effort to increase the efficiency of core expression. The maltose binding protein (MBP) and glutathione S-transferase (GST) protein prokaryotic expression systems were used to study two different constructs, expressing the first 140 and 163 amino acids of the core region. Deletion of the 23 amino acids (aa) from aa141-163 led to a marked increase in the efficiency of protein production from < 1 to 3-4 mg/liter for both systems studied. Protein purification was accomplished using affinity chromatography (MBP) or inclusion body isolation (GST) as determined by SDS-PAGE gels and immunotransblot with HCV core protein-specific monoclonal antibody. Finally, the immune response to recombinant protein was assessed in BALB/c mice using a MBP HCV core fusion protein and an ELISA developed using GST HCV core protein as a target. In all mice of this strain, serum anti-HCV core antibody titer increased to 10(-4), two logs above background, following immunization in conjunction with Freund's complete adjuvant. These results represent an encouraging first step toward production of a core protein vaccine. Recombinant core protein is a useful tool to study the immune response to core protein and may be useful to further study the epidemiology and biology of the HCV virus.

Transplantation of kidneys from donors with hepatitis C antibody into recipients with pre-transplantation anti-HCV

Hepatitis C virus (HCV) is transmitted by organ transplantation. Consequently, several organ procurement organizations have imposed a moratorium on use of organs from anti-HCV positive donors. Because of the inadequate supply of cadaver kidneys for transplantation, we adopted a policy to transplant kidneys from anti-HCV donors into anti-HCV positive recipients. During the period between March 1990 and December 1992, 24 anti-HCV positive dialysis patients received a kidney from anti-HCV positive donors (group I) and 40 anti-HCV positive patients received a kidney from anti-HCV negative donors (group II). We compared the prevalence of liver disease, anti-HCV, HCV RNA, graft and patient survival between groups. Pre-transplantation 17 of 24 (71%) patients in group I and 31 of 40 (79%) of patients in group II had serum HCV RNA. Post-transplantation follow-up was 26 +/- 8 months and 30 +/- 10 months in groups I and II, respectively. During follow-up, elevated ALT levels were present in 7 of 24 (29%) and 16 of 40 (40%) of patients in groups I and II, respectively (P > 0.05). Post-transplantation, all patients in both groups retained anti-HCV. The prevalence of HCV RNA post-transplantation was 22 of 23 (96%) patients in group I and 30 of 39 (77%) of patients in group II (P > 0.05). Graft and patient survival in group I (96% and 100%, respectively) were not significantly different from those in group II (93% and 98%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular detection of hepatitis C virus: impact of detection methodology on clinical and laboratory correlations

The clinical manifestations of hepatitis C virus (HCV) infection are generally indistinguishable from other causes of viral hepatitis. HCV infections are usually anicteric, asymptomatic, and rarely cause acute fulminant liver failure. Serological testing for HCV in conjunction with epidemiological studies have verified that HCV was the major cause of parenterally transmitted non-A, non-B hepatitis (NANBH). With the widespread introduction of serological screening of blood products for HCV antibody, the risk of transfusion-associated HCV infection has been dramatically reduced (to < 3 cases per 10,000 units transfused). Despite the virtual elimination of transfusion-associated infections, the diagnosis of HCV remains important because > 50% of infections are sporadic in origin, 50 to 70% of infected individuals develop chronic hepatitis, and these individuals are at risk of developing cirrhosis (> 20%) as well as hepatocellular carcinoma. Although currently available anti-HCV immunoassays function well as blood-donor screening assays, they are poor at detecting acute infection because of the prolonged lag time between infection and detection of seroconversion (approximately 10 to 26 weeks for second-generation immunoassays). In contrast, polymerase chain reaction (PCR)-based detection of HCV RNA in serum can detect infection in as little as 1 to 2 weeks after exposure. This review focuses on the impact of modern serologic and nucleic acid-based HCV detection methodology on the clinical understanding of HCV infection, its associated illnesses, and its transmissability. Quantitative and reproducible nucleic acid-based detection assays will be required to provide additional insights into the clinical spectrum of HCV infections as well as to assess the efficacy of antiviral agents.

Hepatitis C virus: the nephrologist's view

The last 4 years have been a period of rapid expansion in our understanding of both the molecular biology and clinical significance of hepatitis C virus (HCV) infection. Initial studies using first-generation enzyme-linked immunosorbent assays suggested that the end-stage renal disease population had an exceptionally high prevalence of anti-HCV compared with asymptomatic healthy blood donors. Subsequent analyses with second-generation assays and polymerase chain reaction techniques to detect viremia confirmed these earlier studies. Considering the prevalence of HCV within the dialysis population, it comes as no surprise that several studies confirmed HCV as the leading cause of non-A, non-B hepatitis among renal allograft recipients. Furthermore, transmission of HCV by transplantation of a kidney from an HCV-infected organ donor has been unequivocally demonstrated. The natural history of HCV infection in the immunosuppressed allograft recipient and its impact on long-term patient outcome are still being analyzed. Finally, HCV has been associated with essential mixed cryoglobulinemia and several histologic patterns of immune complex glomerulonephritis, including membranous and membrano-proliferative glomerulonephritis. Although HCV antigen-antibody complexes have not been demonstrated in the kidney, the marked decrease in proteinuria following clearance of HCV RNA with interferon alpha-2b therapy suggests an etiologic role for HCV in these glomerular diseases. Furthermore, the demonstration of HCV RNA in the cryoprecipitate of patients with essential mixed cryoglobulinemia and a beneficial response to treatment with interferon alpha-2b also suggest a role for HCV in the pathogenesis of these clinical syndromes.

Evaluation of third-generation hepatitis C antibody assay in chronic hepatitis C and chronic non-B, non-C hepatitis

Second-generation hepatitis C virus (HCV) antibody assays are more sensitive and specific than first-generation assays in the detection of HCV infection; such tests are widely used. However, there are still HCV-infected patients who test seronegative for anti-HCV even by second-generation assays. In this study we evaluated the performance of the new third-generation HCV assay (HCV 3.0) in 230 individuals with different second-generation anti-HCV (HCV 2.0) and HCV RNA patterns. Our results showed the followings: only one healthy adult had a discrepant result in 200 subjects negative (group I) or positive (group II) for HCV 2.0 and HCV RNA; 7 of 13 (54%) HCV 2.0-negative but HCV RNA-positive patients (group III) were HCV 3.0-positive; two of 17 (12%) so-called chronic non-B, non-C hepatitis patients (group IV) were positive for HCV 3.0. We conclude that third-generation anti-HCV assays are more sensitive and specific than second-generation assays in the detection of chronic HCV infection; however false-positive results may be observed among low-risk healthy persons.

Anti-envelope antibodies in anti-hepatitis C virus (HCV) positive patients with and without liver disease

Our aim was to verify whether the presence of antibodies to HCV envelope protein might mark the occurrence of liver damage, as recently suggested in the literature. Sera from 104 patients (62 male, 42 female) were tested: 84 were positive and 20 were negative to a second generation enzyme immunoassay for anti-HCV antibodies; 51 patients had mild chronic liver disease (44 chronic hepatitis, seven steatosis), 43 had liver cirrhosis (superimposed by hepatocellular carcinoma in 18) and ten were asymptomatic anti-HCV positive subjects with normal liver function tests. Besides, all sera were tested by means of an enzyme immunoassay for the presence of serum antibodies to the synthetic peptide S24A (SIYPGHVSGH RMAWDMMMNW SPTA) derived from amino acids 307-330 of HCV polyprotein. Anti-S24A antibodies were detected in 40/84 sera positive and 1/20 negative at anti-HCV testing (Pearson chi 2 12.29; p = 0.005). Among anti-HCV positive sera, no significant difference existed in anti-S24A status with regard to clinical evidence of liver disease, ALT concentration or HCV RNA positivity. Thus, anti-S24A antibodies are detectable in approximately half of HCV-positive sera, but they do not seem to add significant clinical information to existing tests or to be useful as putative markers of viraemia.

Hepatitis C infection in cadaver organ donors: strategies to reduce transmission of infection and prevent organ waste

The transmission of hepatitis C virus (HCV) by organ transplantation has been unequivocally demonstrated. Among recipients of organs from anti-HCV-positive donors, 57%-96% test positive for HCV RNA. Consequently, several organ procurement organizations have adopted a policy restricting the use of anti-HCV-positive donors to life-saving transplants (heart, liver, or lung). The differences in the rate of transmission of HCV infection by anti-HCV-positive donors could be related to the prevalence of HCV RNA among these donors. In a national collaborative study of 3,078 cadaver organ donors from eight organ procurement organizations in the United States, the prevalence of anti-HCV antibodies and HCV RNA were 4.2% and 2.4%, respectively. The sensitivity and negative predictive value of anti-HCV antibodies for HCV RNA were 100%. However, despite a specificity of 98.1%, the positive predictive value was only 55.1%. Discarding organs from enzyme-linked immunosorbent assay 2-positive donors would eliminate transmission, but organs from 1.88% of donors would be wasted. Clinical and laboratory characteristics did not distinguish anti-HCV-positive donors with and without HCV RNA. Hence, to reduce waste it is necessary to develop confirmatory tests with a higher specificity for HCV RNA than those that are currently available. Even if anti-HCV-positive but HCV RNA-negative donors could be identified and utilized, 2.4% of cadaver organ donors that test positive for serum HCV RNA would remain unsuitable for transplantation of non-life-saving organs. Hence, several authors have suggested the use of kidneys from anti-HCV-positive donors in recipients with pre-existing HCV infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of IgG and IgM HCV antibody secretion in vitro in patients with chronic hepatitis C: correlation with disease activity and response to interferon-alpha

Hepatitis C virus antibodies are found in the serum of most patients with chronic hepatitis C. However, the significance of the humoral response is still uncertain. In this study, in vitro IgG and IgM anti-hepatitis C virus secretion by peripheral blood mononuclear cells of patients with chronic hepatitis C was analyzed. Peripheral-blood mononuclear cells from 21 of 36 patients (58.3%) secreted IgG anti-hepatitis C virus in vitro, as demonstrated with anti-hepatitis C virus-specific enzyme immunoassays and recombinant immunoblot assays. Ten of the 36 patients (27.8%) showed both IgG and IgM anti-hepatitis C virus core in vitro. In 9 of these 10 patients, IgM anti-hepatitis C virus was also detected in serum. Patients with in vitro IgM or IgG anti-hepatitis C virus secretion had higher ALT levels in serum than did patients without such secretion in vitro (99.5 +/- 22.1 and 85.6 +/- 34.4 vs. 38.1 +/- 37.4 U/L; p < 0.0001, p < 0.001). Furthermore, with a histology activity score it was demonstrated that patients with in vitro IgM or IgG HCV antibodies (or both) had more severe chronic active hepatitis than did patients without in vitro hepatitis C virus antibody secretion (p < 0.01). To analyze the therapy outcome, we included in this study 18 patients who had received interferon-alpha previously. Seven of eight in vitro hepatitis C virus antibody-positive patients were nonresponders, whereas the in vitro hepatitis C virus antibody-negative patients were mostly complete therapy responders (8 of 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus infection in Iceland: a recently introduced blood-borne disease

This study demonstrates a very high prevalence of antibodies to hepatitis C virus among Icelandic intravenous (i.v.) drug users. Of 152 identified i.v. drug users 95 (63%) were shown to have antibodies to the hepatitis C virus. In contrast the seroprevalence in the general Icelandic population is low, (0.2%). Almost all cases of hepatitis C virus infection in Iceland are due to i.v. drug use or to use of infected blood or blood products. Sporadic cases with unexplained modes of transmission, a significant portion of hepatitis C infections elsewhere, are virtually non-existent in Iceland. The results of this study are consistent with the hypothesis that the sporadic community-acquired cases could be caused by blood transfer due to bites from insect vectors such as mosquitoes which are not found in Iceland.

Nucleotide sequence of the core region of hepatitis C virus in Pakistan and Bangladesh and the geographic characterisation of hepatitis C virus in south Asia

A large number of complete and partial hepatitis C virus (HCV) sequences have been reported and classified into several genotypes, although none have been reported from South Asia. We have determined and evaluated partial sequences in the core region of HCV obtained from patients with chronic hepatitis in Pakistan and Bangladesh. Nucleotide sequences from these viruses show significant homology with the Japanese HCV-TR isolate (91.7%-97.9%) and low homology with other Japanese, American, and UK isolates including HCV-1, HC-J4, HC-J6, HC-J8, and E-b1 (79.3%-86.2%). The homologies of their deduced amino acids sequence with HCV-1, HC-J4, HC-J6, HC-J8, E-b1, and HCV-TR were 84.3%-89.8%, 85.0-87.9%, 84.1%-86.9%, 84.3%-87.0%, 90.2%-93.1%, and 89.8%-93.5%, respectively. These results suggest that our clones might be classified into the same genotype as HCV-TR. Further analysis using molecular evolutionary methods strongly supported the classification of these sequences with the HCV-TR genotype. Moreover, we could not detect any isolates which were closely related to our clones or HCV-TR in countries outside the South Asian area. These data further support the association of HCV genotypes with distinct geographic regions.

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.

Specificity of the hepatitis C virus NS3 serine protease: effects of substitutions at the 3/4A, 4A/4B, 4B/5A, and 5A/5B cleavage sites on polyprotein processing

Cleavage at four sites (3/4A, 4A/4B, 4B/5A, and 5A/5B) in the hepatitis C virus polyprotein requires a viral serine protease activity residing in the N-terminal one-third of the NS3 protein. Sequence comparison of the residues flanking these cleavage sites reveals conserved features including an acidic residue (Asp or Glu) at the P6 position, a Cys or Thr residue at the P1 position, and a Ser or Ala residue at the P1' position. In this study, we used site-directed mutagenesis to assess the importance of these and other residues for NS3 protease-dependent cleavages. Substitutions at the P7 to P2' positions of the 4A/4B site had varied effects on cleavage efficiency. Only Arg at the P1 position or Pro at P1' substantially blocked processing at this site. Leu was tolerated at the P1 position, whereas five other substitutions allowed various degrees of cleavage. Substitutions with positively charged or other hydrophilic residues at the P7, P3, P2, and P2' positions did not reduce cleavage efficiency. Five substitutions examined at the P6 position allowed complete cleavage, demonstrating that an acidic residue at this position is not essential. Parallel results were obtained with substrates containing an active NS3 protease domain in cis or when the protease domain was supplied in trans. Selected substitutions blocking or inhibiting cleavage at the 4A/4B site were also examined at the 3/4A, 4B/5A, and 5A/5B sites. For a given substitution, a site-dependent gradient in the degree of inhibition was observed, with a 3/4A site being least sensitive to mutagenesis, followed by the 4A/4B, 4B/5A, and 5A/5B sites. In most cases, mutations abolishing cleavage at one site did not affect processing at the other serine protease-dependent sites. However, mutations at the 3/4A site which inhibited cleavage also interfered with processing at the 4B/5A site. Finally, during the course of these studies an additional NS3 protease-dependent cleavage site has been identified in the NS4B region.

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.

Serum levels of soluble immune factors and pathogenesis of chronic hepatitis C, and their relation to therapeutic response to interferon-alpha

To test the role of immune reactivity in the pathogenesis of hepatitis C, serum soluble immune factors were measured in a cohort of 57 patients with chronic hepatitis C, and in 20 healthy subjects. Levels of interleukin-1 beta, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, and interleukin-6 were detected in some, but not all, HCV patients and were in general undetectable in healthy subjects. Patients had significantly higher concentrations of neopterin (P = 0.0026), beta 2-microglobulin (P = 0.046), soluble interleukin-2 receptor (P = 0.021), and soluble CD8 (P < 0.039), than healthy controls; conversely, interferon-gamma levels were significantly lower (P = 0.023). Significant correlations were observed between beta 2-microglobulin concentration and Knodell's index (r = 0.638, P = 0.00045), the score of piecemeal necrosis (r = 0.572, P = 0.0023), and the degree of fibrosis (r = 0.527, P = 0.0056). Interleukin-2 levels correlated significantly with Knodell's index (r = 0.412, P = 0.037), and the degree of lobular cytolysis (r = 0.389, P = 0.048). According to therapeutic outcome, pretreatment levels of soluble CD8 were only significantly elevated (P = 0.042) in patients with a sustained biochemical response. On interferon-alpha treatment, the levels of beta 2-microglobulin, neopterin, and soluble interleukin-2 receptor increased significantly (P < 0.05), irrespective of therapy outcome. In summary, HCV patients have an altered immune reactivity that might play a role in the pathogenesis of chronic hepatitis C, and might influence the therapeutic outcome to interferon-gamma.