Takashi Matsushima

Epidemiology of genotypes of hepatitis C virus in Japanese patients with type C chronic liver diseases: A multi-institution analysis

Sixteen medical institutions in Japan collaborated in this study of the epidemiology of hepatitis C virus (HCV) genotypes. A total of 4176 patients with type C chronic liver disease, from the four main islands of Japan, were evaluated. Of those evaluated, 2794 had chronic hepatitis, 727 had liver cirrhosis and 655 had hepatocellular carcinoma. The HCV genotype of the patients was determined by an enzyme‐linked immunosorbent assay based on serological genotype 1‐ and 2‐specific recombinant peptides (SG‐1 and SG‐2, respectively) of the NS4 region. The prevalence of SG‐1 and SG‐2 HCV was similar in the four main islands of Japan. SG‐1 HCV predominated in each disease category (69–76%). The percentage of patients with SG‐1 HCV increased by 7%, while that of patients with SG‐2 HCV decreased by 7%, as liver disease progressed in severity from chronic hepatitis to carcinoma (P < 0.001). Patients with either SG‐1 or SG‐2 had a similar mean age and history of blood transfusion. In conclusion, SG‐1 HCV was found to predominate in Japan, and the HCV genotype was found to be related to the stage of hepatitis C disease.

Relationship between hepatocellular carcinoma and subtypes of hepatitis C virus: a nationwide analysis.

Although hepatitis C virus (HCV) has now been classified into several subtypes, the clinical significance of HCV subtypes is not well known. Typing of HCV is now routinely performed in Japan. In the present study, HCV subtypes in hepatocellular carcinoma (HCC) patients were analysed from nationwide data collected in Japan using a standard questionnaire. Answers to the questionnaire concerning HCV subtypes in patients with chronic hepatitis (CH), liver cirrhosis (LC) and HCC were obtained from 14 hospitals. The prevalence of the 1b‐related subtype, which includes the mixed subtype of 1b and 2a or 2b, in patients with LC and HCC in each hospital was higher than in patients with CH, with few exceptions. However, the differences were not statistically significant because of the small number of patients in each hospital. In summarized data from all 14 hospitals, the 1b‐related subtype was found in 1370 of 1922 patients with CH (71.2%). In 356 LC and 426 HCC patients, the prevalence of the 1b‐related subtype was 79.8 and 80.5%, respectively. The prevalence of the 1b‐related subtype in patients with LC and HCC was significantly higher than in patients with CH. There was no significant difference between the prevalence of the 1b‐related subtype in patients with HCC and LC. These results indicate that the oncogenic activity of subtype 1b, although not yet clearly characterized, may be stronger than subtypes 2a and 2b.

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.

Changes in hepatitis C virus quasispecies and density populations in patients before and after interferon therapy.

Some chronic hepatitis C patients show sustained response to interferon (IFN) therapy despite viremia. This condition seems to be related to the density populations of hepatitis C virus (HCV) [Kanto et al. (1995): J Med Virol 46:230–237]. To investigate further the relationship between alanine aminotransferase (ALT) levels after IFN therapy and the HCV density populations, we undertook differential flotation centrifugation of HCV and single strand conformation polymorphism targeted the hypervariable region (HVR) of E2 glycoprotein, which seems to be related to the density populations. Sera were obtained serially from 12 patients who had undergone IFN therapy (six sustained responders with viremia, six nonresponders). During the follow‐up after interferon therapy, the HVR heterogeneities changed in 9 of the 12 patients. The remaining three patients whose heterogeneities did not changed persistently showed normal ALT. The changes in HVR heterogeneities were less pronounced in the sustained responders with viremia than in nonresponders; however, their density populations were prominently high in both responders. In two cases, changes in HVR heterogeneities and increase in low‐density virion were observed before the hepatitis flare‐up. These data indicate that HVR quasispecies show more relation to ALT levels after IFN therapy than HCV density populations and that the changes in the HVR sequences and HCV density populations may be associated with ALT elevation in some patients.

Distribution of the different subtypes of hepatitis C virus in Japan and the effects of interferon: A nationwide survey

Interferon (IFN) is now commonly used for the treatment of type C hepatitis; however, its effects differ depending upon the subtype of hepatitis C virus (HCV) being treated. It has been recently confirmed in many studies in Japan that the effectiveness of IFN treatment is poor in patients having type 1b and better in patients having type 2a HCV. However, the effects of IFN treatment on other subtypes of HCV were not clear because of the small number of patients in each hospital. In the present study, the effects of IFN treatment in patients with other HCV subtypes were analysed from nationwide data collected in Japan using a standard questionnaire. From this questionnaire, local differences in the distribution of HCV subtypes in Japan were also analysed. A standard questionnaire, consisting of questions about the number of patients with chronic type C hepatitis with different HCV subtypes and the number of patients showing different responses to IFN treatment, was sent to over 40 study groups in Japan, Answers to the questionnaire concerning HCV subtyes and the effects of IFN treatment were obtained from 26 and 22 hospitals, respectively, throughout Japan. The incidence of HCV type 1b was highest in the Kinki area (south‐central Japan). The incidence of type 1b HCV decreased in parallel with distance from this area. The mortality rates of hepatic cancer in different areas were significantly corrclated with the incidence of HCV type 1b. The efficacy of IFN treatment was significantiy better for both types 2a and 2b HCV than for type 1b HCV; the efficacy of IFN treatment was poor in the mixed type of 1b and 2a and tended to be better in type 1a. The efficacy of IFN treatment for other types of HCV was also better. These results indicate that there are local differences in the distribution of HCV subtypes in Japan and that these differences may be closely associated with the clinical features of HCV‐related liver disease. The efficacy of IFN treatment was significantly poorer in patients with the 1b‐related type HCV than in patients with other types of HCV.

Differential flotation centrifugation study of hepatitis C virus and response to interferon therapy

Hepatitis C virus (HCV) appears to circulate in various forms such as native virion, immune complexes, and nucleocapsids during chronic infections. To determine the association of the physicochemical properties of HCV and its response to interferon therapy in patients with chronic hepatitis C, we examined pretreatment serum samples from 43 patients with HCV RNA who had received interferon therapy, using differential flotation centrifugation in a NaCl solution with a density of 1.063 g/ml. After centrifugation, the ratio of HCV RNA in the top and bottom fractions was determined by the polymerase chain reaction and expressed as T/B. Patients with a sustained response to IFN therapy were found to have higher T/B ratios than transient responders who relapsed after treatment (P < 0.01) and nonresponders (P < 0.01). With regards to HCV genotypes, patients with genotype 1b had higher T/B ratios in the sustained response group than in the nonsustained response group (P = 0.001), but patients with genotype 2 had a similar distribution of T/B among the 3 response groups (not significant). These findings indicate that the physicochemical properties of HCV affect the effectiveness of interferon therapy, particularly in patients with genotype 1b. J. Med. Virol. 52:190–194, 1997.

Treatment of chronic non-A, non-B hepatitis with interferon

SummaryThe efficacy of interferon therapy (IFN) was investigated in 46 patients with chronic non-A, non-B (NANB) hepatitis, of would 40 (87.0%) were positive for anti-HCV antibody (Ab) (C-100-3). Three kinds of IFN were used; human lymphoblastoid interferon (HLBI), interferon alpha-2b and interferon beta. Total doses of IFN ranged from 1 million units (MU) to 10 MU and treatment duration ranged from 2 weeks to 144 weeks. Of 46 patients 34 (73.9%) responded to IFN. Nine patients have maintained normal ALT levels and 5 patients have maintained near-normal ALT levels for more than 6 months after cessation of IFN treatment. In these cases the titers of anti-HCV Ab had decreased significantly at the end of IFN therapy and 6 months after IFN therapy respectively. The mean age was young and the mean disease duration was short in effective cases. As for doses and treatment duration of IFN, low doses of IFN requires long treatment duration to acquire continuous efficacy and high doses of IFN requires rather short treatment durations. Therefore, early IFN treatment, higher doses and longer periods of IFN treatment may improve the response rate of patients with chronic NANB hepatitis.

Early mutation of precore (A1896) region prior to core promoter region mutation leads to decrease of HBV replication and remission of hepatic inflammation.

To evaluate the relationship between mutations and clinical courses, we investigated precore (preC) and core promoter (CP) mutations and serum HBV DNA levels in HBe-antibody-positive HBV carriers. Fifty-six asymptomatic carriers (ASC), 29 patients with chronic hepatitis who showed normal ALT levels for more than two years (CH-ASC), 31 patients with chronic hepatitis (CH), and 32 patients with hepatocellular carcinoma (HCC) were studied. Almost all patients (99.2%) had mutations in either CP or preC. Mutation only in preC (A1896) was present in 52.2% with ASC, 25.0% with CH-ASC, 16.1% with CH, and 8.0% with HCC, and was significantly higher in ASC (P < 0.01). The patients with only preC mutation showed low HBV DNA levels in each clinical stage. The mutation of preC (A1896) prior to the mutation of CP might control the replication of HBV, which leads to the remission of hepatitis.

Nucleotide sequences of the hepatitis C virus core region in patients without anti-core antibody

Second‐generation assays for detection of hepatitis C virus (HCV) infection that include reactivity of antibodies to core, NS3, NS4 are used because of their high sensitivity. Among these antibodies, anti‐core antibody seems to be the most sensitive. However, there are some patients without anti‐core antibodies, although HCV RNA is detectable by reverse transcription‐polymerase chain reaction and branched DNA assay. The mechanism for the absence of anti‐core antibody on its own is unclear. We therefore determined the nucleotide and deduced amino acid sequences of the core region obtained from two anti‐core antibody‐negative patients with HCV RNA (genotype 1b) and compared them with those of four anti‐core antibody‐positive patients and a previously reported sequence. Amino acids spanning 1–47, which seemed to exist in major B cell epitopes, were found to be completely conserved among these patients. Furthermore, the predictive binding motif to HLA DR4 (a.a 81–90) was completely conserved in both of the anti‐core antibody‐negative patients. There were various mutations in the residual amino acids spanning 49–108, but specific mutations could not be found in anti‐core antibody‐negative patients.

Serum HCV RNA levels during early phase of recombinant interferon alfa-2a (Roferon A) therapy for chronic hepatitis C and efficacy of short-term therapy with earlier loss of viremia

We conducted a prospective, controlled, multicenter trial to assess if earlier changes of serum HCV RNA levels were predictable for long-term effect, and if a short-term therapy was effective in such patients. All 377 chronic hepatitis C (CH-C) patients were treated with interferon (IFN) daily 9 MU for 4 weeks. Patients positive for HCV RNA at week 1 were treated with IFN three times weekly for additional 22 weeks (group A), while those negative for HCV RNA were randomized into either regimens; three times weekly for another 22 (group B) or 12 weeks (group C). When complete responders (CR) were defined as the subjects showing sustained loss of viremia with therapy, CR rates were 17.7% (25/141) for group A, 80.0% (36/45) for group B and 61.0% (36/59) for group C, respectively. Group B showed a significantly higher CR rate than group C, indicating that a 16-week treatment period was inadequate. Patients with CR showed a rapid decrease in virus levels by day 2 after starting therapy. The CR ratio in patients with HCV RNA levels of <1.0 Kcopy/ml by day 2 was 64.6% (82/127), while the ratio without <1.0 Kcopy/ml was 12.7% (15/118). CR ratio in patients who became negative by week 2 was 65.7%, whereas only 2.9% after week 2. The results indicate that the determination of HCV RNA levels at day 2 and the qualitative assay at week 2 with IFN are useful in predicting the therapeutic effect.