Chronic hepatitis C: the virus, its discovery and the natural history of the disease

The identification of hepatitis A and hepatitis B led to the recognition that a third virus was capable of causing blood-borne hepatitis. The pathogen responsible for this nonA, nonB hepatitis was identified in the late 1980s and subsequently named hepatitis C. Since the discovery of hepatitis C there has been a pandemic of research publications describing the natural history of the infection and it is now known that this virus can cause serious liver damage in a proportion of infected patients. It is now clear that the effects of infection with hepatitis C and alcohol misuse are additive and that there is an increased risk of hepatic complications in infected patients who abuse alcohol.     

Outcome of acute symptomatic non-A,non-B hepatitis: a 13-year follow-up study of hepatitis C virus markers

ABSTRACT— Thirty-nine of 61 prospectively followed patients who had had acute non-A, non-B hepatitis in 1978 were clinically reexamined in 1991 and tested for antibodies to hepatitis C virus (anti-HCV) with a second generation ELISA and RIBA and for HCV RNA by PCR. Acute hepatitis C was diagnosed in stored sera from 1978 in 24 patients, who were found still to be anti-HCV positive in 1991, and 16 of them were also HCV RNA positive. The majority of anti-HCV positive patients with or without HCV RNA had elevated serum ALT levels 13 years after onset of their acute hepatitis C. After 13 years follow-up, 1.6% of the patients had died of end-stage liver disease, 8% of anti-HCV positive patients had histologically confirmed liver cirrhosis, 79% of anti-HCV positive patients were judged to have chronic infection, whereas 21% seemed to have recovered. To conclude, we found that a majority of our patients with acute symptomatic hepatitis C continued to be viraemic 13 years after onset of hepatitis C, and that all continued to be anti-HCV positive by second-generation ELISA.     

Hepatitis C virus RNA genome in plasma of patients with non-A,non-B hepatitis

Recently, the assay system of anti-hepatitis C virus antibody (HCV-Ab) was developed. However, there is no clinically useful method to detect hepatitis C virus (HCV) itself. The authors recently developed a method to detect the HCV-RNA genome in plasma using polymerase chain reaction (PCR). In the present study, the specificity of this assay in detecting HCV infection was investigated. Freshly obtained 1 ml plasma specimens from 100 patients with various liver diseases and from 11 control subjects were studied. In patients with non-A, non-B (NANB) hepatitis-related liver diseases, HCV-RNA was detected in 2 out of 7 cases of acute hepatitis, in 29 out of 31 cases of chronic hepatitis, in 17 out of 21 cases of cirrhosis and in 2 out of 6 cases of hepatocellular carcinoma. On the other hand, no HCV-RNA was detected in 15 cases of various types of alcoholic liver diseases, in 12 cases of hepatitis B related liver diseases, and in 11 controls. HCV-RNA was detected in 2 of 6 drinkers with chronic hepatitis. The prevalence of HCV-RNA was not closely related to a history of blood transfusions. These results suggest that our method for HCV-RNA is specific for HCV infection and HCV infection is the likely etiology of most chronic NANB hepatitis cases. The clinical usefulness of our method is illustrated by the fact that we were able to study 100 patients and needed only 1 ml plasma per HCV-RNA assay.     

Intrafamilial transmission of hepatitis C virus

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

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

We classified 53 Japanese patients with chronic hepatitis C who were treated with natural interferon- into genotypes and also tested the amounts of hepatitis C virus (HCV) RNA. The rate of the long-term complete response group, whose alanine aminotransferase levels remained within the normal range during the six months after therapy, was significantly higher (P<0.01) in the type-III patients (4/5, 80.0%) than in type-II patients (4/43, 9.3%). For these long-term complete responders, the amounts of HCV RNA was less than 10⁷ copies/ml serum in type-II patients, whereas two type-III patients with relatively high amounts of HCV RNA responded completely. These results confirm that the genotype of HCV is an important factor for predicting the response to interferon therapy. The amounts of HCV RNA can also predict its efficacy in type-II patients.This work was supported by a Grant-in-Aid from the Ministry of Education, Science and Culture, Japan, and the Research Group of Intractable Hepatitis sponsored by the Ministry of Health and Welfare of Japan.     

Hepatitis C virus genotypes and hepatic fibrosis regulate 24-h decline of serum hepatitis C virus RNA during interferon therapy in patients with chronic hepatitis C

BACKGROUND AND AIMS: Recently, hepatitis C virus (HCV) dynamics during interferon (IFN) therapy have been studied in detail. We examined factors that regulate the viral kinetics and the relationship between the viral kinetics and clinical effect of IFN therapy. METHODS: Eighty-eight patients with chronic hepatitis C entered this study. All patients had been treated with 3 MU of IFN-beta twice a day for the first 2-4 weeks, then IFN-alpha for the next 20-22 weeks (three injections per week). The levels of serum HCV RNA were determined by Amplicor HCV Monitor version 1.0, before and 24 h after the first injection of IFN; then the decline of HCV was calculated. Liver inflammation and fibrosis were scored as 0 (none), 1 (mild), 2 (moderate) or 3 (severe) using biopsy specimens. RESULTS: The decline of serum HCV RNA was 1.42 +/- 0.65 log copies/mL in genotype 1b and 1.83 +/- 0.72 in genotype 2a or 2b (P < 0.01). By a logistic regression model, genotype (1b, 2a or 2b) and hepatic fibrosis (0 or 1, 2 or 3) associated with 24-h decline of serum HCV RNA, independently. As the predictor of IFN therapy, the decline of serum HCV RNA and serum HCV RNA levels before IFN therapy were the independent significant factors (P < 0.001). CONCLUSIONS: The decline of serum HCV RNA during the first 24 h of IFN therapy was regulated by genotypes and hepatic fibrosis. The decline of serum HCV RNA and initial HCV load were independent factors that can be the predictor of the subsequent sustained viral response to IFN therapy.     

慢性丙型肝炎患者HCV基因型分析

目的研究慢性丙型肝炎患者HCV基因型概况。方法采用基因芯片法检测HCV基因分型;采用PCR法测定HCV RNA定量。结果在570例患者中,HCV RNA阳性552例（95%）,其中1b型400例（72.4%）,2a型63例（11.4%）,3a型20例（3.6%）,3b型20例（3.6%）,1b＋2a型12例（2.1%）,1a型2例（0.4%）,6型7例（1.26%）,1b＋3a型1例（0.18%）,2a＋1b型3例（0.5%）,未定型24例（4.3%）;不同HCV基因型感染者血清HCVRNA水平无统计学差异（P〉0.05）。结论本组患者HCV基因型以1b型为主,2a型次之,多种混合型的出现提示HCV基因型呈现多样化趋势。     

Clinical predictors of response to recombinant interferon-α treatment in patients with chronic non-A, non-B hepatitis (hepatitis C)

SUMMARY. Chronic non-A, non-B hepatitis (NANBH) is a common and often progressive liver disease. Based on current serological tests, hepatitis C virus (HCV) infection is responsible for most cases. Interferon-α (IFN) treatment at a dose of 3 × 10⁶ units given three times per week for 24 weeks has been shown to be effective in normalizing serum alanine aminotransferase (ALT) levels and reducing hepatic inflammation in approximately 40% of these patients. The purpose of this study was to identify pretreatment characteristics in patients with chronic hepatitis C(CH-C) which would best predict a favourable response to IFN treatment (normalization of serum ALT). One hundred and sixty-three adult patients who had participated in a large multi-centre treatment trial were included in the study group: 84 had been treated with 3 × 10⁶ units of recombinant IFN-α-2b (rIFN) subcutaneously three times per week for 24 weeks and 79 patients had been treated with 1 × 10⁶ units rIFN in the same dosage schedule. Forty-one pretreatment historical, clinical, laboratory and histological variables were evaluated. In addition, early biochemical improvement during treatment was evaluated as a predictor of ultimate response. Univariate analysis identified six variables (dose, dose m^-2, weight, body surface area, ongoing ethanol use, white blood cell count and the presence of symptoms) as potential predictors of response (two-tailed, P < 0.15). By multivariate analysis, however, only the 3 × 10⁶ dose of rIFN was independently predictive of response (P < 0.01). When the analysis of response was confined to those patients who received treatment with 3 × 10⁶ units of rIFN, seven variables [body weight, surface area, dose m^-2, current ethanol use, serum albumin and the presence of chronic persistent hepatitis (CPH) on entry liver biopsy] were more frequent in patients who responded to therapy. In a multivariate model, only CPH and body weight predicted an increased likelihood of response (P < 0.01). However, the model was not a sensitive predictor of response as only 18% of the study group had CPH on liver biopsy. A decrease in serum ALT levels within the first 12–16 weeks of rIFN treatment was found to be the strongest indicator of an ultimate response to treatment. Thus, assessment of early response to IFN treatment is the only practical means of predicting complete response and avoiding prolonged and unnecessary therapy in those with little chance of response.     

Clinical application of hepatitis C virus core protein in early diagnosis of acute hepatitis C

A fluorescence enzyme immunoassay (FEIA) for the quantitative measurement of hepatitis C virus (HCV) core protein has recently been developed. In this study, we studied the clinical usefulness of this measurement in patients with acute hepatitis C. Eighteen patients with post-transfusion acute hepatitis C were enrolled in the study; 5 patients showed resolution of hepatitis with disappearance of HCV viremia, while the remaining 13 patients did not. A second generation HCV antibody, HCV RNA, and HCV core protein were measured in serial serum samples taken within 1 month of the onset of acute hepatitis and 3, 6, 12, 24, and 36 months after onset. Within the first month after disese onset, the positivity rates of HCV RNA (100%; P = 0.0014) and HCV core protein (89%; P = 0.0300) were both significantly higher than that of HCV antibody (56%). Six months after disease onset, the positivity rate of HCV antibody had increased, to 100%, and the pasitivity rates of HCV RNA and HCV core protein began to decrease. HCV core protein levels did not differ between patients with resolved and unresolved disease in the first month after disease onset. These findings indicate that FEIA, a simple assay, for the measurement of HCV core protein was useful for the early diagnosis of acute hepatitis C. (Received May 26, 1997; accepted Nov. 28, 1997)     

Prevalence of antibody to hepatitis C virus in prospectively followed acute non-A,non-B hepatitis,from different epidemiological categories

ABSTRACT— We have studied the prevalence of antibody against hepatitis C virus (anti-HCV) and its relation to the time of onset of the symptoms in 57 patients with acute non-A, non-B hepatitis: 16 post-transfusion, 25 drug addicts and 16 sporadic cases. In the 1st month after the onset of illness, anti-HCV was positive in 25% of patients with post-transfusion hepatitis, 44% of drug addicts and 25% of sporadic hepatitis. In the 3rd month this antibody was detected in 75%, 88% and 31.2%, and in the 6th month in 87.5%, 96% and 31.2%, respectively. The prevalence in the 3rd and 6th months was significantly higher in post-transfusion patients and drug addicts than in sporadic cases. In the 6th month the prevalence of anti-HCV in patients who progressed towards chronicity was also significantly higher than in those with acute resolving non-A, non-B hepatitis (94% vs 50%, p<0.001). These results show that HCV is probably the main agent in acute post-tranfusion non-A, non-B hepatitis and in those occurring in drug addicts, and that in a high proportion of these patients the anti-HCV can be detected in the 3rd month after the beginning of the symptoms. On the other hand, the relation of hepatitis C virus with sporadic acute non-A, non-B hepatitis may be doubtful.     

Assessment of hepatitis C virus RNA and genotype from 6807 patients with chronic hepatitis C in the United States

Hepatitis C virus (HCV) RNA status and HCV genotype have become important tools in the diagnosis and monitoring of therapy in chronic HCV infection. To establish a database with respect to HCV genotype and serum HCV RNA concentrations in chronic hepatitis C patients in the United States, we analysed 6807 chronic hepatitis C patients who had HCV RNA and HCV genotype tests conducted at a central laboratory. The HCV RNA concentration cut-off for the lower 25th percentile of this population (low titre) was 0.9 × 10⁶ copies ml^–1. The median HCV RNA concentration was 3.5 × 10⁶ copies ml^–1 and the cut-off for the upper 25th percentile (high titre) was 5 × 10⁶ copies ml^–1. Male patients had a median HCV RNA concentration of 3.9 × 10⁶ copies ml^–1, which was significantly higher than the median HCV RNA level for females (2.75 × 10⁶ copies ml^–1; P  < 0.001). HCV genotype 1 was detected in 73% of patients; genotype 2 in 14%; genotype 3 in 8%; mixed genotype in 4%; and genotypes 4, 5 and 6 with a frequency of < 1%. Patients from the Northeast, Southeast and Midwest had significantly ( P  < 0.001) more infections with genotype 1 than patients from the Western and Southern regions. African–American patients were more likely to be infected with genotype 1 when compared with Caucasian, Hispanic or Asian Pacific Islanders ( P  < 0.001). Patients infected with HCV genotype 1 and mixed HCV genotypes had significantly higher serum HCV RNA concentrations when compared with HCV genotypes 2 and 3 ( P  < 0.001 for all comparisons).     

Clinical evaluation of the branched DNA assay for hepatitis B virus DNA detection in patients with chronic hepatitis B lacking hepatitis B e antigen and treated with interferon-

The aim of this study was to evaluate the Chiron branched DNA (bDNA) assay for detection of serum hepatitis B virus (HBV) DNA in patients with chronic hepatitis B lacking hepatitis B e antigen (HBeAg) and undergoing interferon (IFN) therapy. Results obtained with the bDNA assay were compared with those obtained using the Abbott liquid hybridization (LH) assay and the polymerase chain reaction (PCR). Serial samples (274) from 34 patients were analysed. Analysis of variance results indicated that bDNA values were more significantly correlated than LH values with both PCR positive/negative results (probability of artifact (Prob>F) = 0.7 and 0.09 for LH and bDNA assays, respectively) and presence/absence of precore mutations (Prob>F = 0.21 and 0.001 for LH and bDNA assays, respectively). Both bDNA and LH results correlated highly with alanine aminotransferase (ALT) values (both had Prob>F values of 0.0) while PCR was not correlated with ALT (Prob>F = 0.05). In 26 evaluable patients, a model based on a generalized Knodell score was used to predict response to IFN therapy, as defined by normalization of ALT values during therapy. This model discriminated well between non-responders and responders. The bDNA results correlated well with the generalized Knodell score, while the LH results did not (Prob>F = 0.04 and 0.19 for the bDNA and LH assays, respectively). In conclusion, the bDNA assay appears to be useful for quantification of HBV DNA levels in HBeAg-negative chronic hepatitis as it correlates with biochemical and histological indications of disease severity as well as with response to IFN therapy.     

输血后丙型肝炎病毒感染的血清病毒定量研究

目的 研究血清丙型肝炎病毒（ＨＣＶ）含量与ＨＣＶ致病的关系及ＨＣＶ含量与抗－ＨＣＶ和丙氨酸转氨酶（ＡＬＴ）的相关性。方法 以逆转录－聚合酶链反应（ＲＴ－ＰＣＲ）法对ＨＣＶ感染的受血及相关供血系列血清进行ＨＣＶ ＲＮＡ定量分析,同时检测ＡＬＴ与抗－ＨＣＶ。结果 致输血后ＨＣＶ感染的供血中,ＨＣＶ ＲＮＡ平均含量为１０＾８．６拷贝／Ｌ,抗－ＨＣＶ及ＡＬＴ的异常检出率随ＨＣＶ ＲＮＡ滴度升高而增加。结论     

Biochemical and structural analysis of the NS5B RNA-dependent RNA polymerase of the hepatitis C virus

Hepatitis C virus (HCV), the major causative agent of chronic and sporadic non-A, non-B hepatitis worldwide, is a distinct member of the Flaviviridae virus family. These viruses have in common a plus-strand RNA genome that is replicated in the cytoplasm of the infected cell via minus-strand RNA intermediates. Owing to the lack of reliable cell culture systems and convenient animal models for HCV, the mechanisms governing RNA replication are not known. As a first step towards the development of appropriate in vitro systems, we expressed the NS5B RNA-dependent RNA polymerase (RdRp) in insect cells, purified the protein to near homogeneity and studied its biochemical properties. It is a primer- and RNA template-dependent RNA polymerase able to copy long heteropolymeric templates without additional viral or cellular cofactors. We determined the optimal reaction parameters, the kinetic constants and the substrate specificity of the enzyme, which turned out to be similar to those described for the 3D polymerase of poliovirus. By analysing a series of nucleosidic and non-nucleosidic compounds for their effect on RdRp activity, we found that ribavirin triphosphates have no inhibitory effect, providing direct experimental proof that the therapeutic effect observed in patients is not related to a direct inhibition of the viral polymerase. Finally, mutation analysis was performed to map the minimal NS5B sequence required for enzymatic activity and to identify the 'classical' polymerase motifs important for template and NTP binding and catalysis.     

Effects of prednisolone pretreatment in interferon alfa therapy for patients with chronic non-A,non-B (C) hepatitis

ABSTRACT— The effect of corticosteroid pretreatment on interferon alfa treatment of chronic non-A, non-B or C hepatitis was evaluated in an open, randomized, controlled study. Normalization of the serum alanine aminotransferase level, which suggested complete response, was recorded in 14 (56%) of 25 patients at the end of a 6-month treatment with 3 million units of interferon alfa three times weekly alone. Prednisolone withdrawal followed by the same interferon alfa treatment resulted in complete response in 14 (61%) of another 23 patients. Both of these rates are significantly higher than the spontaneous ALT normalization rate of 9% observed in 2 of 22 patients during the same period (p<0.01). ALT normalized within 2 months of interferon therapy in most (89%) of the complete responders. Of the patients pretreated with prednisolone, 43% showed a “rebound” following prednisolone withdrawal and 89% of the patients with “rebound” responded to subsequent interferon therapy. The cumulative probability of sustained remission in patients with and without prednisolone pretreatment in a 24-month period of follow-up after the end of therapy was 79% and 30%, respectively (p<0.05). Clinical relapse mostly (85%) occurred within 3 months after the end of therapy. No obvious factor could be identified as a predictor of response or relapse. The results of this study suggest that prednisolone withdrawal tends to enhance the durability of the beneficial effects of interferon alfa therapy in patients with chronic non-A, non-B or C hepatitis.     

A single alcohol ingestion does not affect serum hepatitis C virus RNA in patients with chronic hepatitis C.

BACKGROUND AND AIM: The safe level of alcohol ingestion in sporadic drinkers with hepatitis C is unknown. Our aim was to evaluate the effect of a single moderate alcohol intake on serum HCV RNA concentrations and hepatic function in patients with chronic HCV infection. METHODS: Twenty-one patients with chronic hepatitis C were randomly assigned to consume 50 g alcohol (group 1) or a non-alcoholic beverage (group 2). In both groups, serum ethanol, serum HCV RNA, transaminase and gamma-glutamyltranspeptidase (gamma-GT) levels were measured just before alcohol intake and after 1, 2, 8, 24 h and 1 week's time. RESULTS: The maximum concentration of ethanol in the blood was observed at the first hour after alcohol intake. No significant changes were observed in serum HCV RNA after alcohol intake. Repeated measurements of HCV RNA among the two groups revealed no difference (P = 0.215). Similarly, no difference was observed in transaminase and gamma-GT levels at different time points in each group or among the groups [(ALT (P = 0.082), AST (P = 0.33), gamma-GT (P = 0.538)]. CONCLUSIONS: In patients with chronic hepatitis C, a single intake of 50 g alcohol does not affect liver biochemistry and HCV RNA concentrations. Therefore, it is a matter of further research whether sporadic drinking of light or moderate amounts of alcohol should be avoided in patients with chronic hepatitis C.     

Desperately seeking hepatitis C virus

Spanish investigators described recently the so-called occult hepatitis C virus （HCV） infection, emphasizing the detection of genomic and antigenomic HCV RNA strands in liver and peripheral blood mononuclear cells. Therefore, the persistence of viral replication in occult HCV infection should be considered as a putative source of infection among family members and patients undergoing invasive procedures, transfusion or transplantation. Additionally, the most worrisome finding is that an occult HCV infection may persist in patients with sustained virological response.