Detection of HCV RNA in subjects with antibody to hepatitis C virus among the general population of Fukuoka, Japan

An overview about hepatitis C: a devastating virus

Hepatitis C (HCV) is the disease that has affected around 200 million people globally. HCV is a life threatening human pathogen, not only because of its high prevalence and worldwide burden but also because of the potentially serious complications of persistent HCV infection. Chronicity of the disease leads to cirrhosis, hepatocellular carcinoma and end-stage liver disease. HCV positive hepatocytes vary between less than 5% and up to 100%, indicating the high rate of replication of viral RNA. HCV has a very high mutational rate that enables it to escape the immune system. Viral diversity has two levels; the genotypes and Quasiaspecies. Major HCV genotypes constitute genotype 1, 2, 3, 4, 5 and 6 while more than 50 subtypes are known. All HCV genotypes have their particular patterns of geographical distribution and a slight drift in viral population has been observed in some parts of the globe.

Hepatitis C virus (HCV) infection: a systemic disease

Hepatitis C virus (HCV) infection is a global health problem, being the second most common chronic viral infection in the world with a global prevalence of about 3% (about 180 million people). HCV is both an hepatotropic and a lymphotropic virus; and chronic infection could cause, on one hand, chronic hepatitis, cirrhosis and hepatocellular carcinoma and on the other hand several extrahepatic diseases including, first, mixed cryoglobulinemia and lymphoma. The association between hepatic (hepatocellular carcinoma) and extrahepatic (lymphoma, thyroid cancer) malignancies has justified the inclusion of HCV among human cancer viruses. The pathogenesis of HCV-related sequelae (hepatic or extrahepatic) is not fully understood representing a challenge of prime importance in light of the optimization of clinico-therapeutic management of these patients. Combined treatment with pegylated interferon plus ribavirin is presently the first-line, gold standard treatment of most HCV-related diseases. However, mainly in the case of extrahepatic manifestations, a cautious approach to the patient, with a case to case accurate tailoring of therapy is frequently requested. The present review will outline the principal aspects of such HCV-induced systemic disease focusing on extrahepatic manifestations.

Global epidemiology of hepatitis C virus infection

Hepatitis C virus (HCV) is a major cause of liver disease worldwide and a potential cause of substantial morbidity and mortality in the future. The complexity and uncertainty related to the geographic distribution of HCV infection and chronic hepatitis C, determination of its associated risk factors, and evaluation of cofactors that accelerate its progression, underscore the difficulties in global prevention and control of HCV. Because there is no vaccine and no post-exposure prophylaxis for HCV, the focus of primary prevention efforts should be safer blood supply in the developing world, safe injection practices in health care and other settings, and decreasing the number of people who initiate injection drug use.

A prospective study of blood transfusion history and liver cancer in a high-endemic area of Japan

BACKGROUND

The high prevalence of liver cancer in Japan may be owing to infection with hepatitis C virus (HCV), for which the major transmission route is blood transfusion. However, among the general population, there have been few follow-up studies of people with a history of transfusion. The purpose of this study was to examine whether such a history correlates with the development of liver cancer among the general population of this high-endemic area.

STUDY DESIGN AND METHODS

The baseline survey was conducted between 1986 and 1991 among the population (15,597 people, aged 30-79) of Fukuoka prefecture, Japan. The participants were assessed for their transfusion history and other covariates using a baseline questionnaire. The relative risk (RR) of blood transfusion for liver cancer was estimated using the Cox proportional hazard model.

RESULTS

The RRs of transfusion for subsequent liver cancer were 1.86 (95% confidence interval (CI) = 1.05-3.29) in men and 4.20 (95% CI = 1.83-9.61) in women, after adjusting for covariates. Transfusion was associated with an increased risk of liver cancer, mainly in the group without hepatitis and cirrhosis (RR = 1.81, 95% CI = 0.84-3.91 - men; RR = 4.39, 95% CI = 1.37-14.02 - women).

CONCLUSION

A history of blood transfusion carried a significant risk of developing liver cancer in the study region. The people with a history of transfusion should be monitored more aggressively for viral infections and liver disease, as they may not report the infection or they may be unaware that they are infected.

Prospective study of diabetes mellitus and liver cancer in Japan

BACKGROUND

Previous studies have identified the association between diabetes mellitus and liver cancer. However, the detail of this association is still unclear, in terms of confounding factors, the trend according to the duration of diabetes, and the interaction between diseases associated with the liver cancer and this association. The purpose of the present study was to examine the association between diabetes and liver cancer in view of the trend and the interaction.

METHODS

The baseline survey was conducted during the period 1986-1989 among the general population of Fukuoka Prefecture, Japan (15 417 persons aged 30-79 years). The respondents were assessed for history of diabetes, age at which they had had diabetes, and other covariates by means of a baseline questionnaire. A total of 7308 persons aged 40-79 years were retrieved for the main analysis and 4902 persons for a subcohort from which the information on history of diseases associated with liver cancer were obtained. The relative risks (RRs) and their 95% confidence intervals (CIs) were estimated using the Cox proportional hazards model.

RESULTS

After adjustment for smoking, alcohol and the diseases associated with liver cancer, the RR for liver cancer was 2.06 (95% CI=1.01-4.19). Diabetes increased the risk of liver cancer in persons with hepatitis and/or cirrhosis (RR=2.90, 95% CI=1.13-7.41). However, the RR of diabetes for liver cancer was 1.35 (95% CI=0.41-4.43) in persons without hepatitis and cirrhosis. The trend according to the duration of diabetes was not seen.

CONCLUSIONS

A significant association between diabetes and liver cancer was observed. Moreover, this association was modified by hepatitis and cirrhosis.

Epidemiology of hepatitis C virus infection in Italy: the slowly unraveling mystery

In spite of the large diffusion of hepatitis C virus (HCV) infection and its high association with liver disease, the epidemiology of HCV in Italy is still unclear. This review collects all the data available on the prevalence and incidence of HCV infection in Italy and compares them with those reported in other countries.

Occasional infection of hepatitis C virus occurring in haemodialysis units identified by serial monitoring of the virus infection

To examine whether hepatitis C virus (HCV) infection still occurs in haemodialysis units even after a decrease in the number of blood transfusions and in those contaminated with HCV, we tested anti-HCV antibodies and HCV RNA in 142 patients from Japanese haemodialysis units, and examined the serial prevalence of anti-HCV antibodies in 86 patients from 1992 to 1997. A high prevalence of HCV infection was observed: 34 (23.9%) and 38 (26.8%) of the 142 patients were positive for serum anti-HCV antibodies and HCV RNA, respectively. These positive rates were related to the duration of haemodialysis. We found that five patients treated in the same unit seroconverted from 1993 to 1995. Four of the five patients had been treated at the same shift and were affected at the same time. Phylogenetic analysis of the hypervariable region 1 (HVR1) sequence of HCV from serum of these patients showed that three of the four patients' sequences were phylogenetically clustered and that two of the three were closely related. Thus, an occasional transmission of HCV occurred in the haemodialysis unit. The universal precautions by staff such as carefully changing gloves may be important in inhibiting spread of HCV because no instances of infection have been seen since the instigation of educational measures for unit staff.

Prospective study on the relation of cigarette smoking with cancer of the liver and stomach in an endemic region

BACKGROUND

Smoking has not been confirmed as a risk factor for cancers of the liver and stomach. The authors examined prospectively the relationship between smoking and these cancers in an endemic region.

METHODS

The data used were a cohort study on the relationship between lifestyle and health in the region having the highest liver cancer mortality in Japan. Of the cohort members, 4050 males aged > or =40 years were included in the present analysis with a 9-year mean follow-up. Cox proportional hazards regression was used to estimate relative risks (RR) for cancer of the liver, stomach, smoking-related sites and others, while adjusting for age, residence, and alcohol intake.

RESULTS

By the end of the study period, 59 cases of liver cancer and 53 cases of stomach cancer were identified. Current smokers, compared to subjects who had never smoked, had a threefold risk of liver cancer (RR = 3.3; 95% CI: 1.2-9.5) and a twofold risk of stomach cancer (RR = 2.2; 95% CI: 0.8-5.7). Sub-cohort analysis showed that adjustment for history of chronic liver disease did not attenuate the risk of liver cancer. Light/medium smokers had almost the same risk of these cancers as heavy smokers, while they showed a relatively low risk of smoke-related cancers.

CONCLUSIONS

The present results indicate that smoking is a risk factor of liver and stomach cancer in a population with a high background risk for these cancers. However, causal inferences should be made cautiously due to a lack of information on known risk factors.

Increased frequency of interferon-gamma-producing peripheral blood CD4+ T cells in chronic hepatitis C virus infection

OBJECTIVES

To determine the profile of cytokine secretion by CD4+ T helper (Th) cells in chronic hepatitis C virus (HCV) infection, we used flow cytometry to determine the percentage of interferon (IFN)-gamma and interleukin (IL)-4 producing cells from CD4+ T lymphocytes in peripheral blood obtained from patients chronically infected with HCV.

METHODS

Peripheral blood mononuclear cells isolated from 89 HCV infected subjects (22 asymptomatic carriers, 56 patients with chronic hepatitis, and 11 patients with liver cirrhosis) and 24 healthy controls were stained with surface CD4 and intracellular IFN-gamma and IL-4. Serum soluble IL-2 receptor (sIL-2R) levels were analyzed by ELISA.

RESULTS

The frequency of IFN-gamma producing CD4+ cells in asymptomatic HCV carriers, patients with chronic hepatitis, and patients with liver cirrhosis were significantly higher than those of healthy controls (p<0.01, respectively). In contrast, the percentages of IL-4-producing CD4+ cells were very low, and there were no significant correlations with disease progression. A significant elevation in serum sIL-2R levels was found in chronic HCV infection compared to healthy controls, and serum sIL-2R levels significantly correlated with the frequency of IFN-gamma-producing cells.

CONCLUSIONS

In HCV infected subjects, both serum sIL-2R and IFN-gamma are increased in chronic HCV infection no matter the stage of disease, meaning they are no different in asymptomatic carriers, patients with chronic hepatitis, and patients with liver cirrhosis, and that Th1 cytokine or Th1 cells may participate in the pathogenesis of liver damage in chronic HCV infection.

A cohort study of hepatitis C virus (HCV) infection in an HCV epidemic area of Japan: age and sex-related seroprevalence of anti-HCV antibody, frequency of viremia, biochemical abnormality and histological changes

We studied the age- and sex-specific prevalence of hepatitis C virus (HCV) infection and aminotransferase abnormalities as well as histological changes in the liver associated with HCV infection. Of the eligible 3,707 inhabitants aged 6 years and older in an HCV infection epidemic area 2,382 (64.3%) were examined. The anti-HCV positivity rate was 20.7% on average and increased according to age. Age was the most potential risk indicator for anti-HCV positivity by multiple stepwise regression analysis. The HCV RNA positivity rate in females with anti-HCV was significantly lower than that in males. However, as the age of females increased, the HCV RNA positivity rate became higher. The proportion of subjects with aminotransferase abnormalities among HCV RNA-positive subjects was significantly lower in females than males. Aminotransferase abnormalities significantly increased with age in females. In subjects with abnormal aminotransferase levels, nearly half of the HCV RNA-positive females were aged 50 or older and also nearly half of the male subjects showed CAH2B or liver cirrhosis, while most of the HCV RNA-positive females younger than 50 exhibited histological findings consistent with CPH. In conclusion, age was the principal risk indicator for HCV infection in this area. Females, especially those younger than 50, both biochemically and histologically showed less severity of HCV infection than males. Gender and age might have effects on the outcome of HCV related liver disease.

Hepatitis C viral RNA status at two weeks of therapy predicts the eventual response

We investigated the timing of the disappearance and reappearance of serum hepatitis C viral (HCV) RNA in patients with chronic hepatitis C during interferon treatment and follow-up. Serum samples were tested for HCV RNA by polymerase chain reaction in 62 patients with chronic hepatitis C treated with interferon-alpha for 24 weeks. We found that 17 patients obtained complete response, with absence of serum HCV RNA for 6 months after the treatment. Twenty-nine patients had a partial response, with reappearance of serum HCV RNA within 6 months of follow-up, and 16 patients were nonresponders who were positive for serum HCV RNA throughout the observation period. HCV RNA disappeared within 2 weeks of treatment in 31 patients, including all 17 (100%) complete responders and 14 (48.3%) of the 29 partial responders. The patients remaining positive for HCV RNA at the second week were 15 (51.7%) of the 29 partial responders and the 16 nonresponders. In all of the 29 partial responders, viremia recurred within 1 month after the treatment. These results indicate that the status of HCV RNA at the second week of treatment is a useful predictor of effective treatment, whereas status at the first month after cessation of treatment is useful for assessing the effectiveness of interferon itself.

Hepatitis C virus seroconversion rate in a hyperendemic area of HCV in Japan: a prospective study

We have studied the prevalence, seroconversion rate of anti-hepatitis C virus (HCV), and the transmission of HCV in a cohort of individuals living in a hyperendemic area of HCV in Japan. We investigated 509 subjects, of which 375 could be studied again after 5 years. A remarkable high prevalence of anti-HCV (23.4-24.0%) was observed. Of 287 subjects negative at the first examination in 1990, 4 became positive until the second in 1995 (seroconversion rate: 0.28% per year). Furthermore, we investigated the route of transmission in HCV seroconverted subjects through a detailed interview. All of the HCV seroconverted subjects had past histories of medical treatment. Seroconversion rates of HCV in a hyperendemic area of HCV, were extremely high. Medical treatment was considered to be a causative route of HCV transmission.

Hepatitis C virus infection-associated markers in sera from blood donors in Surabaya, Indonesia

Among 2,233 sera obtained from volunteer blood donors, 259 (11.6%) showed elevated alanine aminotransferase (ALT) levels. A second-generation enzyme-linked immunosorbent assay (ELISA) revealed that 23 (8.9%) of the 259 sera were positive for antibodies against hepatitis C virus (HCV), whereas only 9 (1.4%) of 646 sera randomly collected from blood donors with normal ALT levels were positive (P < 0.001). The overall prevalence of anti-HCV antibodies among blood donors was estimated to be 2.3%. HCV RNA was detected in 19 (83%) of the 23 anti-HCV-positive sera with elevated ALT levels, and 8 (89%) of the 9 sera with normal ALT levels. Among the anti-HCV-positive sera, IgM anti-HCV was detected in 5 (22%) of 23 sera with elevated ALT levels and in 2 (22%) of 9 sera with normal ALT levels. All of the IgM anti-HCV-positive sera were positive for HCV RNA, irrespective of ALT levels.

Evaluation of quantitative assay for antibody to hepatitis C virus core in patients treated with interferon

We titrated antibody to hepatitis C virus (anti-HCV) core of serum samples from 57 patients with chronic HCV infection, in an attempt to clarify the relationship between the level of HCV RNA and the outcome of interferon treatment. The patients studied were positive for both anti-HCV, by second-generation assay, and HCV RNA, by polymerase chain reaction, and had been treated with interferon for six months. Of the 57 patients, HCV RNA was eliminated in 16 by the time of discontinuation of interferon treatment (CR); in 19 this elimination was transient (PR) and for 22 elimination was nil (NR). The low HCV RNA level was accompanied by high titers of anti-HCV core while high HCV RNA levels were accompanied by low titers of anti-HCV core, with an inverse correlation (r = -0.322, P < 0.05). The mean titer of anti-HCV core before interferon treatment was 324 units in CR, 205 in PR, and 168 in NR, with a correlation ratio of 0.382 (P < 0.05). A decreased titer (more than 50%) was found in 68% of the CR. At the time of six-month follow-up, the anti-HCV core titers of CR had decreased by more than 50%, compared to pretreatment titers, while in PR and NR, there was an increase to above the pretreatment titers, without increases in HCV RNA levels or worsening of the hepatitis. In conclusion, quantitative assay for anti-HCV core is useful to assess the status of HCV replication.

Serum levels of soluble interleukin-2 receptors and effects of interferon-alpha for patients with chronic hepatitis C virus

To characterize the role of serum soluble interleukin-2 receptor (sIL-2R) in hepatitis C virus (HCV) infection, the level of sIL-2R was measured by ELISA in 117 subjects with chronic HCV infection and in 23 healthy controls. HCV RNA was detected by polymerase chain reaction in all subjects with HCV infection. Forty-seven patients with chronic hepatitis and 10 with liver cirrhosis were treated for six months with natural interferon-alpha. The sIL-2R levels of 40 asymptomatic HCV carriers (632 +/- 340 units/ml), 47 patients with chronic hepatitis (547 +/- 204 units/ml), 10 with cirrhosis (679 +/- 239 units/ml, and 20 with hepatocellular carcinoma (1145 +/- 487 units/ml) were significantly higher than those of healthy controls (380 +/- 191 units/ml) (P < 0.05, respectively). The levels of sIL-2R increased, as did the histological activity index scores (r = 0.348, P < 0.01). The level of sIL-2R rose after the initial administration of interferon in all 57 patients. In patients whom HCV RNA was eliminated from the sera within a six-month follow-up after cessation of treatment, the level of sIL-2R reverted to basal values, but in patients in whom HCV RNA was not eliminated the value was significantly higher than that before treatment. These results suggest that monitoring serum sIL-2R in patients with chronic HCV infection treated with interferon may provide information concerning the possibility of the elimination of HCV RNA.

Relationship of genotype to level of hepatitis C viraemia determined by competitive polymerase chain reaction

To compare the levels of hepatitis C virus (HCV) viraemia in carriers of the same genotype in various stages of chronic HCV infection, we quantified the amount of HCV RNA by competitive polymerase chain reaction and determined HCV genotype using type-specific primers. The study population included 255 patients with chronic HCV infection (asymptomatic 33, chronic hepatitis 141, liver cirrhosis 50, hepatocellular carcinoma 31). Of these 255, the prevalence of HCV RNA genotype II was 67.8%, genotype III, 17.3% and genotype IV, 14.9%; no genotype I was found. The level of HCV RNA (logarithmic transformed copy numbers per 50 microliters of serum) was significantly higher in subjects of genotype II than in those of genotypes III or IV (mean titre 5.8 +/- 1.0 vs. 5.1 +/- 1.2 and 4.8 +/- 1.1, P < 0.05, respectively). There was no significant difference in the level of HCV RNA between genotypes III and IV. Of 173 patients of genotype II, there were no significant differences between the level of HCV RNA and the stage of liver disease or in the level of HCV RNA by age. Of the 129 with genotype II with a history of blood transfusion, there was no significant difference between the level of HCV RNA of patients with and without a history of transfusion or between that of patients with a history of blood transfusion and the time elapsed since blood transfusion. The level of HCV viraemia depended on the genotype of HCV RNA and did not correlate to age or to the stage of liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Inverse correlation between the titre of antibody to hepatitis C virus and the degree of hepatitis C viraemia

We titrated 277 hepatitis C virus (HCV) antibody-positive serum samples from 235 volunteer blood donors as well as from 42 outpatients of a hospital for elderly people and studied the relation of the titre of HCV antibody to the presence of HCV RNA, of antibody to C100 protein (anti-c100) and of antibody to GOR epitope (anti-GOR). Liver dysfunction was measured also. Of 177 HCV RNA-positive serum samples, 87 were tested for the degree of HCV viraemia by means of a competitive assay. Among the 277 samples, prevalences of HCV RNA, anti-c100, anti-GOR and liver dysfunction were 63.9%, 71.8%, 75.7% and 17.5%, respectively. The prevalence of HCV RNA became higher as the titre of HCV antibody increased. The titre tended to increase with age but the tendency was not statistically significant. The mean titre was higher in females (2(10.4 +/- 1.8)) than in males (2(9.4 +/- 2.2)) (P < 0.01). In the HCV RNA-positive serum samples, the HCV antibody titre was significantly higher in the anti-c100-positive samples than in the negative ones. This difference between the positive and negative samples, however, was not statistically significant for anti-GOR and liver dysfunction. Low degrees of HCV viraemia were accompanied by high titres of HCV antibody while high degrees of HCV viraemia went with low titres of HCV antibody. The study revealed that titres of HCV antibody were higher in females and the degree of HCV viraemia correlated inversely with the titre of HCV antibody.