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Hepatitis C virus subtype 3a (HCV-3a) originates from Asia and has spread widely among injecting drug users as well as other patient groups in industrialized countries. HCV subtype 3a infection remains highly prevalent and frequently transmitted in the population of intravenous drug users. The objective of this study was to understand better the mechanisms of the worldwide HCV-3a epidemics in drug users. Ninety-three sera from HCV-3a-infected IDUs from France, the United States, Brazil, Argentina, and Australia were studied. Phylogenetic analyses of the non-structural 5B region showed no specific clustering according to the continent of the patient's origin. Non-exclusive clusters of viral sequences from South America, Australia, and California were observed, but topologies were not supported by strong bootstrap values. The results suggest that HCV-3a has been transmitted from a common origin through a unique worldwide epidemic that rapidly spread among drug users. Regional transmission occurred in the recent past, leading to an embryonic genetic diversification of HCV-3a among local injecting drug user population.

Background & Aims: We have observed a high prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection in heart transplant recipients (HTRs). The aim of this study was to assess the epidemiology, natural history, and clinical and biological characteristics of viral hepatitis in HTRs., Methods: From 1983 to 1992, 874 patients underwent heart transplantation at the Pitié-Salpêtrière Hospital, Paris, France, 459 of whom qualified for analysis. A total of 140 patients had posttransplantation hepatitis B, C, or non-A-E. Sixty-nine patients developed HBV infection, 49 HCV infection, 11 HBV-HCV coinfection, and 11 non-A-E hepatitis., Results: HBV was transmitted nosocomially from patient to patient, most likely during endomyocardial biopsies. HCV was mainly transmitted through blood transfusions or the transplanted organ. Clinical and biological findings after 2 years of follow-up showed that 3 patients with an HBV genotype A precore mutant had severe or subfulminant hepatitis and that patients with HBV and HCV infection always progressed to chronicity. In general, patients had mild alanine aminotransferase level increases, a high level of viral replication, and few severe histologic lesions, except for patients infected by precore HBV mutants. Patients coinfected by HBV and HCV tended to have more severe liver lesions. The survival rate 5 years after transplantation in patients with viral hepatitis (HBV, 81%; HCV, 89%; HBV and HCV coinfection, 100%; non-A-E hepatitis, 73%) was similar to that in patients without liver test abnormalities (76%). The actuarial survival curve was also similar in patients with or without liver test abnormalities., Conclusions: In our experience, histologic liver lesions do not progress rapidly in patients with post-heart transplant infection caused by HBV or HCV. HBV or HCV infection seems to have little impact on the 5-year survival rate of HTRs.

During 1994 and 1995, the prevalence of hepatitis C virus (HCV) and its genotypes were studied in several rural and urban populations in three West African countries: Guinea, Burkina Faso, and Benin. The following groups were screened for antibodies to HCV (anti-HCV): 459 villagers in the forest region of Guinea; 965 individuals in urban, suburban, and rural populations of the Bobo Dioulasso area, Burkina Faso; and 582 blood donors in Cotonou, Benin. In Benin, 60 patients with sickle cell anemia (30 with and 30 without history of multiple transfusion) and 13 hospital patients with liver disease were also tested. RT-PCR detection of HCV-RNA was carried out on all anti-HCV positive samples, followed by genotyping and sequencing of unrecognized subtypes. The prevalence rates of anti-HCV were 1.1% in the Guinean population group, 1.4% among blood donors in Benin, and 4.9% in residents of Burkina Faso. In patients with sickle cell anemia, five of the 30 polytranfused patients (17%) had anti-HCV, whereas none of the patients without a history of blood transfusion had anti-HCV (P < 0.05). Among the 13 patients with liver disease, five had anti-HCV, of whom four had history of blood transfusion. HCV-RNA was detected in 41 anti-HCV positive sera. All belonged to genotypes 1 or 2, with a high genomic diversity; 18 different subtypes were identified, including 2c, 2d, and 16 new subtypes. Such genetic diversity poses a challenge for vaccine development and also implies that HCV infection is long-established in these West African regions.

Acute and chronic Hepatitis C virus infections were investigated retrospectively in chimpanzees that had been infected from a single source. Anti-E1 and anti-E2 were detected in two of three chimpanzees with a chronic infection, but were first detected 1 to 2 years after inoculation. Sequence evolution of the E1 region in three animals over a period of 9 to 11 years revealed a mutation rate of 1.02 to 2.23 x 10(-3) base substitutions per site per year. The acute phase viremia levels in acute infections which resolved appeared to be at least 10-fold higher than during the acute phase of chronic infections. During chronic infections, the viral load fell rapidly after the acute phase and remained at very low levels for several years. After 4 to 6 years, the viral load and liver enzymes increased again, suggesting reactivation of the infection. There was no clear temporal relationship between sequence evolution of the E1 region, changes in viral load, and the production of antibodies to the envelope proteins.

Background/aims: Studies of HCV quasispecies during interferon treatment have shown the selection of resistant clones. Enomoto et al. have defined the interferon sensitivity-determining region in an amino acid stretch of the HCV-1b NS5A region. Patients with a mutant strain before treatment were complete responders, whereas those with wild-type HCV-J strain were resistant to interferon. The same region was studied in HCV isolates of French patients., Methods: Forty-three HCV-1b chronically infected patients, consisting of 26 non-responders and 17 complete responders to interferon-alfa treatment (3 MUI tiw for 6 months), were included retrospectively. We directly sequenced the NS5A(2209-2248) HCV region of these patients before treatment. The viral load could be obtained from six complete responders and 15 non-responders., Results: We detected wild-type and intermediate strains, but only two mutant strains were present. One of them was found in a non-responder. In three complete responders, we found a wild-type strain. The distribution of the various strains was rather different from that found in Japan. Before treatment, the viral load was lower in complete responders (p=0.01)., Conclusions: Only two mutant strains were detected in our study. This could partially explain the low response rate to interferon treatment of French HCV-1b-infected patients, although the dose regimen was lower than in Japanese studies. Also, wild-type strains were found in some complete responders, and no correlation was determined between the mutation number in the NS5A(2209-2248) region and response to alfa interferon therapy. This may be related to epidemiological differences between HCV-1b strains present in France and those in Japan. Searching for the mutant NS5A pattern before treatment does not appear to be useful in French patients as it is too uncommon.

Background/aims: To investigate host- and virus-related factors predictive of early and sustained alanine aminotransferase normalization after interferon therapy for HCV-related chronic liver disease, in an area where genotype 1 is highly prevalent., Methods: We studied 100 patients with HCV-RNA positive chronic liver disease (73 chronic hepatitis and 27 cirrhosis) undergoing alpha-interferon treatment. Thirty-four patients had an early response but relapsed, 15 patients remained into sustained response for at least 12 months after therapy, and 51 patients did not respond. Serum HCV-RNA levels were assessed by bDNA (Chiron), and genotype by LiPA (Innogenetics) and by sequencing of the 5' non-coding region., Results: Mean pre-treatment HCV-RNA level (x 10(3) genome equivalents/ml +/- SD) was lower in sustained responders (3854 +/- 7142) than in relapsers (9587 +/- 10163) or in non-responders (5709 +/- 6618). HCV subtype 1b was highly prevalent (82%), while types 1a, 2a, 3 and 4 were rare (about 5% each). However, the prevalence of 1b was much lower (31%) under 40 years of age. The prevalence of subtype 1b among sustained responders (74%) was similar to that observed among relapsers (82%) or non-responders (84%), but some nucleotide substitutions in the putative RNA loop of the 5' non-coding region were seen only among relapsers or non-responders. Multiple logistic regression model showed that early response to interferon was predicted by absence of cirrhosis and a pre-treatment HCV-RNA level below 350. Sustained response to interferon was predicted by pre-treatment HCV-RNA level below 350 and a low fibrosis score., Conclusions: Among patients with hepatitis C from an area where subtype 1b is highly prevalent, absence of cirrhosis and low pre-treatment serum HCV-RNA level are the most important predictors of response to IFN. Some nucleotide substitutions found in the 5' non-coding region of subtype 1b are associated with non-response or relapse.

Between February 1991 and January 1992, elevated alanine aminotransferase (ALT) levels were observed in several hemodialysis patients in a dialysis center in Dendermonde, Belgium. By the end of 1992, 25 out of 68 patients had seroconverted for HCV antibodies. The HCV strains from 23 of these seroconverters were genotyped and classified as genotype 1b. Sequence analysis of the HCV Core region was carried out in 12 patients, 9 of whom were infected with a strain bearing a unique sequence motif as compared with the currently known HCV 1b strains. A new 5' UR/Core line probe assay was designed to screen for such variations. Twenty patients tested positively for this special sequence motif, while the other 3 showed the regular subtype 1b sequence. Phylogenetic analysis of the Core sequences further revealed that the latter three were neither related to the main special strain of the infection, nor to each other. These three strains could be traced to two patients already infected at the time of residence in other dialysis units and to one patient who already showed ALT elevations in 1989. Epidemiological studies revealed no traceable source for this outbreak. In conclusion, molecular analysis demonstrates nosocomial transmissions by a peculiar genotype 1b strain in a dialysis center. Three other genotype 1b strains were also present in the unit, but were not responsible for the outbreak.

The quality of the hepatitis C virus (HCV)-specific T-cell response may greatly determine the course of an HCV infection. An adequate T-cell response may contribute to a successful clearance of the virus and a rapid recovery from the disease. An inadequate response may lead to viral persistence and may eventually contribute to the pathogenesis of hepatocellular damage in chronic disease. The effect of interferon alfa (IFN-alpha), presently the most popular therapeutic agent for chronic HCV infections, on HCV-specific T-cell responses is completely unknown. To demonstrate the presence of HCV-specific T lymphocytes during chronic HCV infections, to know their antigenic specificities, and to examine possible effects of IFN-alpha treatment on their presence and antigen recognition patterns, we have stimulated peripheral blood mononuclear cells (PBMC) from 35 chronic HCV patients with nine pools of synthetic peptides representing the HCV Core, E1, and E2 proteins as well as with a recombinant NS3 protein. The proliferative responses of PBMC from 16 healthy control subjects toward these antigens were measured for comparison. Lymphoproliferative responses of patients with chronic HCV infections were assayed either before (in 10 patients), during (in 13 patients), or after (in 21 patients) treatment with IFN-alpha. The analysis showed that PBMC from most HCV patients consistently recognized the COOH-terminal part of the core protein. E1, E2, and NS3 were recognized less frequently. This recognition pattern was not related to the therapy with IFN-alpha nor to the clinical response of the patient toward this therapy. The response to the Core protein could be fine-mapped to the COOH-terminal region encompassing amino acids (aa) 73 to 92, 121 to 140, 145 to 164, and 157 to 176.

The prevalence of hepatitis C virus (HCV) antibodies, HCV infection, and genotypes was studied in a rural population of the Central African Republic. In five villages, blood samples were taken from all the inhabitants present during the survey, belonging to Pygmies (299) and to Bantu and Banda ethnic groups (247). Using a second-generation ELISA screening and confirmation by immunoblot assay for the detection of HCV antibodies, all the Pygmies were negative, whereas seven Bantus/Bandas, aged > 35 years and with no familial relationship, were positive, giving a prevalence of 2.8% in this ethnic group. Five samples were also PCR positive; all belonged to genotype 4, but with three new subtypes identified by phylogenic analysis. These results indicate the co-existence of different HCV subtypes and raise questions about the natural transmission of HCV in this secluded population.

Antihepatitis C virus (HCV) IgM antibodies were found in patients with both acute and chronic hepatitis C. The aims of the study were to determine the significance, in terms of liver disease and virological parameters, of anti-HCV core IgM antibodies in the serum of patients with chronic hepatitis C, and the possible relationship between the presence of these antibodies before treatment and biochemical and virological responses to interferon therapy. Sixty-one patients with chronic hepatitis C were studied. Tests for serum anti-HCV core IgM antibodies were carried out before treatment. The patients received 3 mega units of interferon alpha-2a subcutaneously thrice weekly for at least 3 months (6 months when alanine aminotransferase activity was normal at month 3). A biochemical response to interferon therapy was defined as normal alanine aminotransferase activity at the end of treatment (month 6: biochemical response) and 6 months later (month 12: sustained biochemical response). A sustained virological response was defined as serum HCV RNA negativity by a polymerase chain reaction-based detection method (PCR) in patients with normal alanine aminotransferase at month 12. Anti-HCV core IgM antibodies were detected in 28 of the 61 patients (46%). The prevalence of these antibodies was significantly higher in patients infected with HCV genotype 1 (including subtypes 1a and 1b) than in patients infected with other genotypes (including 2a and 3a) (57% vs. 17%; P < 0.01). No significant difference was found between IgM-positive and IgM-negative patients as regards the mean age, sex ratio, serum alanine aminotransferase and gamma-glutamyl transpeptidase activities, the prevalence of cirrhosis in liver biopsy specimens, detection of HCV RNA by PCR, and quantitation by branched DNA assay. At month 6 of interferon therapy, normal alanine aminotransferase activity was significantly more frequent in IgM-negative than in IgM-positive patients (52% vs. 21%, respectively; P < 0.02). At month 12, normal alanine aminotransferase activity and PCR negativity were significantly more frequent in IgM-negative than in IgM-positive patients (18% vs. 0%, P < 0.04). It is concluded that anti-HCV core IgM antibodies in serum are significantly more frequent in patients infected by HCV type 1 than by other types. This suggests that their overall prevalence in patients with chronic hepatitis C in industrialized countries, where HCV type 1 accounts for the majority of infections, would be of the order of 50%, that anti-HCV core IgM antibodies are not associated with characteristic features of liver disease, and that their presence before treatment is associated with a failure of interferon alpha therapy to clear the virus.

Background/aims: The importance of determining the hepatitis C virus genotype has increased since several authors have described a good correlation between hepatitis C virus genotype and response to interferon treatment or to disease severity. It is thus of particular importance to develop reliable assays for hepatitis C virus genotyping., Methods: We have comparatively analyzed hepatitis C virus genotypes of 208 French and Italian chronically infected patients using genotype-specific primers polymerase chain reaction in the capsid region and a genotype-specific probe-based assay in the 5' untranslated region (LiPA)., Results: We found a good concordance between the two assays for the prevalent genotypes in our regions (145/174). The nucleotide sequences in the 5'UTR and capsid domain were investigated to determine the molecular basis of some discordant results. This analysis showed that the genotype-specific probe-based assay gave more consistent results, probably because this technique is based on several probes distributed along the 5'UTR to reveal each genotype. In contrast, the low variability of 5'UTR did not always permit classification of the hepatitis C virus genotype 1 subtypes. We also found some problems, using genotype-specific primers polymerase chain reaction, for less represented genotypes; in particular, in the presence of type 2a/III we obtained more discordant results. This observation is of importance in view of the potential association of this genotype with mild liver disease and a good response to interferon-a treatment.

This study examined the relationships between hepatitis C virus (HCV) genotypes and the routes of HCV transmission in 101 patients with chronic hepatitis C. Patients who received blood transfusions (43%) and those with chronic hepatitis C of unknown cause (37%) had similar mean ages, age distribution, and HCV genotype distribution (1a, 19% vs. 14%; 1b, 52% vs. 54%; 3a, 10% vs. 9%; other, 19% vs. 23%). Intravenous drug users (IVDUs) were significantly younger and had a different genotype distribution (1a, 33%; 1b, 0; 3a, 63%; other, 5%; P < .001). Transmission of HCV 3a has been observed only over the past 20 years; other genotypes were transmitted up to 40 years ago. These results suggest that for 20 years there have been two independent ongoing hepatitis C epidemics. One affects persons who received blood transfusions or whose source of infection is unknown. These persons are older and are mainly infected by HCV 1b. The second type of infection occurs in IVDUs and infects younger persons, mainly with HCV 3a.

Objective: To define parameters determined before and after 4 weeks of interferon therapy (3 MU three times per week for 24 weeks) which could be reliable predictors of a response to therapy., Patients: Thirty-four patients with chronic hepatitis C virus (HCV) infection were investigated prospectively., Methods: A complete response was defined as the normalization of serum alanine aminotransferase levels (ALT) at the end of treatment. The genotype of HCV was determined and the level of HCV-RNA was quantitated both before and after 4 weeks of treatment., Results: After 4 weeks, 16 out of 20 responders [95% confidence interval (CI) 54-94%] and two out of 14 non-responders (95% CI 2-44%) normalized their ALT levels (P = 0.0002). The prevalence of genotype 1b was significantly (P < 0.04) higher among non-responders (eight out of 10; 95% CI 44-92%) than in responders (four out of 18; 95% CI 4-40%). Before treatment, the viraemia determined by branched DNA was significantly lower in responders than in non-responders (46.4 versus 116 x 10(5) eq virus/ml). After 4 weeks of treatment, the level of viraemia in responders was still significantly lower than that in non-responders (22.8 versus 66 x 10(5) eq virus/ml). In responders, a significant decrease in the level of viraemia was observed after 4 weeks of treatment., Conclusion: In a stepwise regression analysis only age and the normalization of ALT levels after 4 weeks of treatment were predictive of response to interferon at the end of treatment.