HCV genotypes in different countries

Prevalence of hepatitis C virus genotypes in risk groups in the Republic of Macedonia: a 5 years survey

The prevalence of hepatitis C virus (HCV) genotypes depends on geographical location. HCV genotyping is important for epidemiological investigations and treatment management. The aim of this study was to determine the HCV genotype prevalence in the most prominent risk groups in the Republic of Macedonia in the last 5 years and to evaluate its association with patient's age, gender, and mode of transmission. A total of 1,167 HCV positive patients, divided into three risk groups (intravenous drug use, chronic hemodialysis, and other risk factor), were genotyped using an in-house ASO hybridization method with genotype-specific oligonucleotide probes. The genotypes 1, 2, and 3 were present with 52.2%, 0.6%, and 47.0%, respectively. Genotype 1 was most prevalent in hemodialysis (89.0%) and other risk factor group (53.8%). It was found associated independently with hemodialysis, age >40 and female gender. Genotype 3 predominated in intravenous drug users (64.0%) and was associated significantly also with age ≤40 and male gender. Multivariable logistic regression analysis pointed out hemodialysis (P < 0.0001, Exp (B) = 12.0) as a positive predictor factor for genotype 1 and age ≤40 (P = 0.021, Exp (B) = 1.8) and intravenous drug use (P < 0.0001, Exp (B) = 8.4) as a positive predictor factors for genotype 3. In conclusion, the main transmission route of HCV infection in the Republic of Macedonia is intravenous drug use, followed by hemodialysis. HCV genotypes 1 and 3 dominate in these two most prominent risk groups in the Republic of Macedonia.

Tracing the spread of hepatitis C virus in Turkey: a phylogenetic analysis

BACKGROUND/AIMS

Molecular epidemiology of hepatitis C virus (HCV) shows that HCV genotypes are unique with respect to their nucleotide sequence, geographical distribution and clinical relationship.

METHODS

In this study we enrolled 67 HCV-infected individuals with various stages of liver disease from four geographical regions of Turkey. A partial NS5B region of the HCV genome was sequenced and subjected to phylogenetic analysis to determine the circulating HCV genotypes and subtypes.

RESULTS

The results showed that HCV genotype 1 (subtype1b) is the main genetic variant of HCV in Turkey but did not reveal any Turkish indigenous phylogenetic cluster. Phylogenetic analysis showed that Turkish strains have their closest matches from both Asia (Japan) and Europe/USA.

CONCLUSIONS

In view of Turkey's geographic position, HCV-1b transmission from Europe is not exceptional. This study could not establish a clear role of other HCV genotypes prevalent in neighboring Asian countries in Turkey's HCV transmission, which would need to be confirmed by further regional epidemiological studies.

Distribution of hepatitis C virus genotypes in patients infected by different sources and its correlation with clinical and virological parameters: a preliminary study

Background

Information about genotypes and associated risk factors in hepatitis C virus (HCV) infected patients in Iran is limited. The aim of this study was to identify the HCV genotypes and associated risk factors in a group of HCV infected patients from Iran.

Results

Genotyping analysis was performed in 156 patients with positive anti-HCV and HCV-RNA. Patients were questioned concerning documented risk factors. Genotypes 1 and 3 were found in 87 (55.8%) and 45 (28.8%) patients, respectively. The most frequent HCV subtype was 1a (37.8), followed by 3a (28.9%) and 1b (16.7%). There was no statistically significant difference between the risk factors analyzed and the acquisition of HCV infection. We further found that 18 (40%) and 17 (37.8%) patients that were intravenous drug users (IVDU) had genotype 1a and 3a respectively.

Conclusion

Genotypes 3a and 1a in Iran are less prevalent in IVDU than in Europe and USA, but there is a high similarity between the pattern of genotype in IVDU in both Europe and United States, and Iran. However, in this case it can not be due to people migration among countries since history of travel abroad existed only in 6 cases (13.3%).

Pathomorphological Characteristics and Pathogenesis of Viral Hepatitis

Viral hepatitis (VH) is an inflammatory reaction of the liver to hepatotropic viruses. Acute VH can be classified according to the virus and type of necrosis. Chronic hepatitis (CH) might be active, persistent or lobular based on previous classification. More recently the grade (necroinflammatory activity) and stage (fibrosis and architectural distorsion) of CH have been distinguished and scored. Apoptosis and necrosis probably coexist in VH and contribute to hepatocyte death. Several "death factors", such as transforming growth factor b, Apo1/Fas and tumor necrosis factor play a role in the execution of cell death. Injury of hepatocytes during viral infection can occur as a direct effect of the virus or as a result of the host immune response. Expression of different viral antigens can be detected during VH and might be visualized. Phenotyping of the portal inflammatory cell infiltrate in CH has shown a T-cell zone comprised of CD4+ helper T cells and CD8+ supressor/cytotoxic T cells at the periphery of the lobules. The pathogenetic mechanisms responsible for the final outcome of viral infection depend on viral factors (such as genotype, mutation etc.), virus-host interaction, expression of viral protein, several cytokines etc. which finally lead to the well known histological alterations of viral hepatitis.

Hepatitis C virus clearance is prominent in women in an endemic area

BACKGROUND

The clinical and virological backgrounds of cases with previous hepatitis C virus (HCV) infection (positive for HCV antibody (anti-HCV) and HCV-RNA negative) in an HCV endemic area were examined to identify factors related to the clearance of HCV.

METHODS

The study population comprised 3117 inhabitants, 1037 male and 2080 female, from an HCV endemic area. Hepatitis C virus antibody was detected by a passive haemagglutination test. The HCV-RNA and the HCV genotype were detected by using the polymerase chain reaction method. The HCV serotype was determined by enzyme immunoassay by using the peptides of the core region.

RESULTS

Twenty-two per cent of the inhabitants were positive for anti-HCV, with males and the elderly having a significantly higher antibody titre (P < 0.01) than youths and females. Hepatitis C virus-RNA was detected in 78% of the HCV antibody-positive cases. The rate of HCV-RNA positivity was significantly higher in males than in females (P < 0.01). No relationship was found between HCV-RNA positivity and age. The HCV genotype 1b was the predominant genotype among the HCV-RNA-positive cases. Mixed genotypes (1b + 2a) were observed in 12% of cases, primarily in elderly males and females. In cases with previous HCV infection, serotype 1 was the most common serotype, and there appeared to be no relationship between the distribution of HCV serotypes and age and gender. There was a female predominance with regard to previous HCV infection, but not to being HCV carriers (P < 0.01).

CONCLUSIONS

Gender, not HCV genotype, is the primary factor influencing HCV clearance.

[Characteristics of the hepatitis C virus and viral predictors of therapeutic response]

NATURAL HISTORY OF HEPATITIS C-INFECTION AND VIRAL CHARACTERISTICS: Hepatitis C-virus (HCV) infection is a major cause of non-A, non-B-hepatitis and, additionally, is associated with liver cirrhosis and hepato-cellular carcinoma. The high degree of chronificity of HCV-infection is reasonable due to antigenic variability of neutralizing epitopes leading to incomplete immunoresponse with subsequent virus persistence. Besides genetic variants of HCV within a virus population (quasispecies nature of HCV), different genotypes are classified being genetically and phenotypically distinct, and geographically restricted in part. Genotyping of HCV is not only important for phylogenetic and epidemiological studies, but also a predictive marker for pathogenesis and therapy. VIRAL PREDICTORS OF HCV THERAPY: In a meta-analysis of 18 therapeutical studies of chronical HCV infections, genotype 1 and high levels of viremia determined markedly the response to interferon therapy. In this context, clinical trials have proven the effect of a combined therapy with interferon and ribavirin. Especially patients with HCV genotype 1 or high levels of viremia had a real benefit from combined antiviral therapy in comparison to monotherapy with interferon. CONCLUSION AND FUTURE CONCEPTS: Besides recent concepts improving the therapeutical response to HCV infection, further effort is necessary to develop more successful strategies for eradication of hepatitis C virus. In this context, variations of interferon therapy should be evaluated (e.g. higher and daily doses, longer duration of interferon therapy, "retarded" interferon (PEG-IFN). In addition, new therapeutical concepts should be performed including a combination of interferon with other known antiviral agents (amantadine), a combination with immunomodulators (GM-CSF, thymosin alpha 1), the development of new antiviral agents (inhibitors of viral proteases, helicases and polymerases) and the exploration of anti-viral, molecular strategies (specific ribozymes, antisense oligonucleotides and DNA-vaccination). Nevertheless, the development of an effective vaccination should be the most important challenge for the future.

Genomic characterization of Brazilian hepatitis C virus genotypes 1a and 1b

Parts of 5' non-coding (5' NC) and of E1 envelope regions of the hepatitis C virus (HCV) genome were amplified from sera of 26 Brazilian anti-HCV antibody-positive patients using the reverse transcription-polymerase chain reaction (RT-PCR). Fourteen samples were PCR positive with primers from the 5' NC region and 8 of them were also positive with primers from the E1 region. A genomic segment of 176 bp from the E1 region of 7 isolates was directly sequenced from PCR products. The sequences were compared with those of HCV strains isolated in other countries and the Brazilian isolates were classified by phylogenetic analysis into genotypes 1a and 1b. This could have a clinical importance since it has been shown that individuals infected with type 1 viruses are less likely to respond to treatment with interferon than individuals infected with types 2 and 3 viruses. Two quasispecies isolated from the same patient with an interval of 13 months differed by two base substitutions (1.1%). The sequence of another isolate presented a three-nucleotide deletion at codon 329.

Distribution of hepatitis C virus genotypes in German patients with chronic hepatitis C: correlation with clinical and virological parameters

BACKGROUND/AIMS

The hepatitis C virus genotypes have been shown to be differently distributed between distinct geographical areas and to be associated with different clinical presentations. In the present study we investigated the distribution of HCV genotypes in 379 German patients with chronic hepatitis C in relation to age, sex, route of infection, liver histology and viremia.

METHODS

Typing of HCV was done using restriction fragment length polymorphism analysis as well as a DNA enzyme immunoassay. HCV RNA concentrations were determined by quantitative polymerase chain reaction. Liver biopsies were performed in 187 patients and the histological activity was graded by the Knodell score.

RESULTS

Seventy percent were infected with genotype 1 (20% subtype 1a, 80% subtype 1b), 4% with genotype 2 and 26% with genotype 3 (all subtype 3a). Genotype 3a and 1a infection was significantly associated with intravenous drug abuse. In contrast, genotype 1 predominated in patients with post-transfusion hepatitis and infection of unknown origin. A changing relative prevalence of HCV genotypes in relation to age was also observed. Patients with genotype 3 infection showed significantly lower HCV RNA levels and a lower mean histological activity score as compared to patients with genotype 1 and genotype 2. However, using multivariate analysis, only age and mode of transmission but not histological activitiy score were shown to be independent variables.

CONCLUSIONS

Our study confirms previous reports from other countries that HCV variants can be classified into a relatively small number of discrete genotypes, and that the subtype 1b clearly predominates. However, we found evidence that there is a changing relative prevalence of HCV genotypes in relation to age, and that the mode of transmission is reflected in the predominance of certain genotypes.

Antibody responses to hepatitis C envelope proteins in patients with acute or chronic hepatitis C

Antibody responses to the hepatitis C virus (HCV) envelope proteins E1 and E2 were analyzed using two original assays in sera from 86 patients in different stages of disease. A Western blot assay and an immunofluorescence assay (IFA) were developed using envelope proteins produced, respectively, in Escherichia coli and in CV1 cells infected with a recombinant SV40. As a third method, the INNO-LIA HCV Ab III assay including E2 synthetic peptides was used. Of 38 chronically infected patients positive for anti-E2 antibodies by IFA, 26 were positive in the Western blot assay (68%) and 25 in the INNO-LIA test (66%). Thus, the detection of anti-envelope antibodies is highly dependent on the antigen formulation, and a native glycosylated form of the proteins is probably needed for their efficient detection. This study shows that the antibody response to HCV envelope proteins depends on the phase of infection. A few acutely infected patients displayed a response to E1 or E2 (36% by Western blot, 7% by IFA), and these antibodies seem to develop in patients evolving toward chronicity. The high prevalence in chronically infected subjects (62% to E2 by Western blot, 90% by IFA), particularly in subjects with essential mixed cryoglobulinemia (68% and 100%), confirms that the resolution of infection involves more than these antibodies. The antienvelope response in patients treated with interferon was investigated, but no significant relationship was found between antibody level prior to treatment and the evolution of hepatitis. The detection of anti-envelope antibodies, therefore, is not predictive of the response to antiviral therapy.

Phylogenetic tree-based epidemiological analysis of hepatitis C virus transmission in a region of Japan with a high prevalence of infection

Local clustering of hepatitis C virus (HCV) infection has been demonstrated in various regions in Japan. HCV genotypes have now been compared between infected individuals from districts of Saga prefecture with either a high (H district) or low (L district) prevalence of HCV-seropositivity. The prevalence of HCV genotype 1b was significantly higher (P < 0.001) in the H district (45/50; 90%) than in the L district (19/36; 52.8%). A phylogenetic tree was constructed based on the genomic sequences of viral isolates from 20 patients infected with genotype 1b in the H district. Almost all these HCV strains clustered in the same regions of the tree. With regard to risk factors for HCV transmission, the percentage of patients with a history of surgery was significantly higher in the H district than in the L district (58 versus 33.3%; P < 0.05). Of 20 patients infected with similar strains of HCV in the H district, 16 (80%) had at least one parenteral risk factor associated with medical care. These results indicate an increased transmission of similar strains of HCV in the H district as a result of nosocomial infection.

Response to interferon in chronic hepatitis C due to mixed genotype infection

We examined the response to interferon (IFN) in patients with chronic hepatitis C (CHC) due to two different genotypes of hepatitis C virus (HCV) infection. Among 64 CHC patients studied, one (2%) had HCV-RNA genotype I, 36 (56%) had genotype II, 19 (30%) had genotype III, 2 (3%) had genotype IV and 6 (9%) had both genotypes II and III. There was no significant difference in age, sex, history of blood transfusion and liver histology among patients with genotypes II, III and II + III. The HCV-RNA titre of genotype II patients was significantly higher than that of genotype III patients (P < 0.05). However, there was no significant difference in the HCV-RNA titre between genotype II + III and the other groups. The complete response rate achieved with IFN therapy was significantly higher in genotype III patients (74%) than in genotype II patients (17%; P < 0.01). Of the six patients with genotype II + III, a complete response to IFN was only achieved by two patients (33%), both of whom had a low HCV-RNA titre ( < or = 10(4.5) copies/mL) and HCV serotype 2. The remaining four patients had HCV serotype 1 and three of the patients had a high HCV-RNA titre ( > or = 10(5) copies/mL). The HCV genotype III was lost in two patients after IFN therapy. These data suggest that HCV-RNA titre and HCV serotype are important factors for predicting the efficacy of IFN therapy in patients with mixed genotype infection and show direct evidence of higher susceptibility towards CHC of patients with genotype III than genotype II.

Detection of feline herpesvirus 1 DNA by the nested polymerase chain reaction

The thymidine kinase region of feline herpesvirus 1 (FHV 1) genome in ocular/nasal swabs from cats with clinical manifestations of upper respiratory disease was amplified by nested polymerase chain reaction (nested PCR). Two primer pairs were prepared for nested PCR. FHV 1 DNA in ocular/nasal swabs was extracted using instaGene-DNA purification matrix. Nested PCR for the FHV 1 culture supernatants was ten times as sensitive as single PCR. On comparing viral isolation with single PCR and nested PCR for the detection of FHV 1 in ocular/nasal secretions, of 5 samples that yielded infectious virus in cell culture, 3 (60%) were positive in single PCR and 5 (100%) were positive in nested PCR. When 22 ocular/nasal swabs that did not yield FHV 1 were assayed, 3 were negative in both single PCR and nested PCR, 2 were positive in both single and nested PCR and 17 were positive in only nested PCR. Thus, FHV 1 was detected in 19/22 (86.4%) by the nested PCR and in 2/22 (9%) by single PCR. These results show that nested PCR is 4.8 (24 positive samples/5 positive samples) times as sensitive as single PCR.

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.

Genotyping of hepatitis C virus: coinfection by multiple genotypes detected in children with chronic posttransfusion hepatitis C

The distribution of genotypes of the hepatitis C virus (HCV) was studied in 24 children with chronic posttransfusion hepatitis C. Genotypes were determined by reverse transcription-nested polymerase chain reaction with type-specific primers. Twenty (83%) were infected by a single genotype: 14 by type II [1b], 3 by III [2a], and 3 IV [2b]. Four (17%) were coinfected by two genotypes. The amount of blood transfusion given to the patients infected by multiple genotypes was significantly larger than to those infected by a single genotype (mean +/- SD, 15.2 +/- 14.4 vs 78.6 +/- 42.0 U). Three of the four patients infected by multiple genotypes were considered to be immunocompromised by anticancer therapy for malignant disease. Eighteen patients showed a raised level of alanine aminotransferase throughout the follow-up, while the remaining six patients (three of type II [1b], two of IV [2b], and one of III [2a] + IV [2b]) achieved biochemical remission. Liver biopsy was performed on 19 patients. Compared to those with type III [2a] or IV [2b], those with type II [1b] appeared to show more severe histological changes with higher histological activity index scores, although there was no significant difference. The positive rates of antibody to C100-3 or 5-1-1 in patients with type III [2a] or IV [2b] were lower than in those with type II [1b] (33 and 33 vs 43 and 50%), whereas the antibody to C33C or C22-3 was detected in nearly all patients regardless of their genotypes. In the present study, we found a high incidence of multiple-genotype infection among children with chronic posttransfusion hepatitis C.

Virology of hepatitis C virus

Hepatitis C virus (HCV) has been identified as the main causative agent of posttransfusion non-A, non-B hepatitis. Through recently developed diagnostic assays, routine serologic screening of blood donors has prevented most cases of posttransfusion hepatitis. The purpose of this paper is to comprehensively review current information regarding the virology of HCV. Recent findings on the genome organization, its relationship to other viruses, the replication of HCV ribonucleic acid, HCV translation, and HCV polyprotein expression and processing are discussed. Also reviewed are virus assembly and release, the variability of HCV and its classification into genotypes, the geographic distribution of HCV genotypes, and the biologic differences between HCV genotypes. The assays used in HCV genotyping are discussed in terms of reliability and consistency of results, and the molecular epidemiology of HCV infection is reviewed. These approaches to HCV epidemiology will prove valuable in documenting the spread of HCV in different risk groups, evaluating alternative (nonparenteral) routes of transmission, and in understanding more about the origins and evolution of HCV.

Mother-to-infant transmission of hepatitis C virus: a prospective study

To investigate the risk of mother-to-infant transmission of hepatitis C virus (HCV) and the natural course of HCV-infected infants, we prospectively studied 31 offspring of pregnant women who were anti-HCV positive and anti-HIV negative. Sera were serially tested for anti-HCV by the second-generation ELISA-test (ELISA-2) and for HCV-RNA by the polymerase chain reaction procedure. The mean period of follow up was 19 months (range 6-41 months). The presence of HCV-RNA in the mothers was associated with a high titre of anti-HCV by ELISA-2 or a positivity of the second generation recombinant immunoblot assay. At birth, 26 babies were positive for anti-HCV. Passively transferred maternal antibodies became undetectable within 2-15 months. HCV-RNA was detected in only 3 infants (9.7%) within 1-4 weeks after birth and persisted thereafter. The genotype of HCV-RNA in each of the infants was consistent with that of their mother. These 3 showed chronic transaminase elevation during the follow up that started at 1-2 months of age, although they revealed no clinical symptoms. Reelevation of anti-HCV titre was observed in the HCV-infected infants within 10 months of age, suggesting an endogenous production of anti-HCV. The mean titre of HCV-RNA in three mothers of infected infants was higher than that in the mothers of uninfected infants (10(5.3 +/- 0.3) vs 10(4.4 +/- 0.2)/ml).

CONCLUSION

Our findings indicate that HCV was most likely to have been transmitted from mothers to infants at the time of delivery and that it was capable of evoking the chronic carrier state.

Hepatitis C virus genotypes in patients with chronic liver disease and haemodialysis patients from Saudi Arabia

The genotypes of hepatitis C virus (HCV) were investigated in 28 Saudi patients (21 males, seven females; age range 23-68 years; mean 45.0 years) with histologically proven chronic hepatitis (13 chronic active hepatitis and 15 liver cirrhosis) and in 32 Saudi patients with chronic renal failure maintained on haemodialysis (22 males, 10 females; age range 18-60 years; mean 40.0 years) who also had liver disease due to HCV. Among the 28 patients with chronic liver disease genotype 4 was the predominant one (60.7%), followed by types 1b (21.4%), 1a (14.3%) and 2a (3.6%). The distribution of genotypes was similar in patients with chronic active hepatitis to those with liver cirrhosis. Among the 32 patients with chronic renal failure and maintained on haemodialysis, genotype 4 was also the dominant type (55.0%), followed by 1a (25.0%), 1b (21.9%) and 2a (3.1%). In all categories studied the prevalence of genotypes between males and females was the same. As our patients were selected from various regions of Saudi Arabia, we believe that genotype 4 is the predominant one throughout the whole kingdom.

HCV genotypes in Swedish blood donors as correlated to epidemiology, liver disease and hepatitis C virus antibody profile

Sixty-two anti-HCV and HCV-RNA positive Swedish blood donors (44 men, 18 women; median age 34 years) were studied. HCV genotypes were correlated to parenteral risk factors, liver morphology, serum alanine aminotransferase (ALAT) levels and HCV antibody profile. Forty percent of the donors were infected with HCV genotype 1a, 10% with 1b, 21% with 2b, and 29% with 3a. Intravenous drug use (IVDU) was more common in donors with genotype 3a than in those with genotype 1a (p = 0.024), and prior blood transfusion more common in genotype 2b than in 3a (p = 0.012). Chronic active hepatitis with and without cirrhosis was found in 38% of donors infected with genotype 2b as compared to 8% of donors infected with 1a (p = 0.034). Forty percent of donors with genotype 1a had normal ALAT at the time of liver biopsy versus 11% with genotype 3a (p = 0.046). Antibodies to C33c and C22-3 were present in nearly all donors whereas reactivity to C100-3 and 5-1-1 was detected more often in donors with genotypes 1a and 1b as compared to donors with genotypes 2b and 3a. In conclusion, genotype 3a was correlated to IVDU or tattooing as parenteral risk factors for the acquisition of HCV infection, and genotype 2b to prior blood transfusion. Donors with genotypes 1a seemed to have less severe liver disease than those infected with genotypes 2b and 3a.

Genotypes and virus load in patients with hepatitis C infection

Virus load was tested by means of PCR calibrated with standards and HCV genotypes were determined by the LIPA-technique using sera from 123 HCV patients. Of these 39 were on renal hemodialysis treatment, 19 suffered from hemophilia, 13 were i.v. drug users and the remaining 52 had none of these risk factors (chronic hepatitis group). The most prevalent subtype in Austria was 1b followed by 3a and 1a. However, genotype 1b infections were found relatively less often in hemophilia patients and drug users than in the other groups, indicating that hemophiliacs probably had been infected by an antihemophilic plasma coming from South American or Asian donors. The highest amounts of virus were found in patients infected with genotype 3a. Determination of the patient's virus load and of the infecting subtype of HCV may be helpful in planning interferon alpha therapy.

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.

Seroprevalence of hepatitis C virus infection and its genotype in Lanzhou, western China

The seroprevalence of hepatitis C virus (HCV) infection in Lanzhou, Western China was studied. HCV genotypes in 20 patients with HCV infection was determined by genotype-specific primer for polymerase chain reaction (PCR) based on HCV core region and compared with the genotype assigned by sequence comparison and molecular evolutionary analysis based on the same region. Antibody to HCV (anti-HCV) was present in 2.5% of volunteer blood donors and in 35.0% of paid blood donors (P < 0.01). HCV infection is uncommon in patients with liver disease who attended liver clinics in this locality; 4.0% with acute hepatitis and 4.0% with chronic hepatitis, 10.0% with liver cirrhosis, and none with hepatocellular carcinoma were seropositive for anti-HCV. Genotype 1b and 2a were both found to be prevalent. Together, they accounted for 19 of 20 (95%) patients with HCV infection. Sequencing of the HCV core region from two patients showed that the assignment of HCV genotype by genotype-specific primers for PCR matched well with the genotyping results based on sequence comparison and molecular evolutionary analysis. These data showed that HCV is present in Western China, HCV infection is more common in paid blood donors, and HCV genotypes 1b and 2a are both prevalent in Western China.

Current status of the molecular genetics of hepatitis C virus and its utilization in the diagnosis of infection

BACKGROUND

Since the discovery of hepatitis C virus (HCV) as a major cause of non-A non-B hepatitis, advances have been made in our understanding of the molecular biology of HCV and its relatedness to the flaviviruses and pestiviruses. The use of molecular techniques to construct an antibody assay has enabled the accumulation of information concerning the natural history and pathogenesis of HCV infection.

OBJECTIVES

The objective was to review the literature to March 1994 on the structure, function and genetics of HCV and to correlate these findings with approaches to diagnosis that have contributed to our understanding of HCV infections.

STUDY DESIGN

We reviewed the virological and medical literature from 1988 to March of 1994 with a focus on the stated objectives.

RESULTS

Although the structure of HCV has been well-defined, our knowledge of the function of all the genes of HCV is incomplete. Structural core and envelope proteins as well as enzymes have been described. The 5' end of the polypeptide is most conserved. Genotyping of isolates varies according to the part of the gene examined. Several genotypes exist and tend to predominate in global populations. Antibodies to the various proteins can be measured by EIA assays and positive specimens often require confirmatory testing. Uniquely sensitive nucleic acid detection systems for RNA amplified by PCR have enabled a better understanding of the natural history, epidemiology and responses to treatment.

CONCLUSIONS

Well-designed studies for the detection of nucleic acid, antibodies and antigens using a variety of viral gene products will provide even more information about HCV infections and help lead to treatment and prevention.

Risk of hepatocellular carcinoma in patients with cirrhosis in Japan. Analysis of infectious hepatitis viruses

BACKGROUND

The development of hepatocellular carcinoma (HCC) is associated closely with cirrhosis. In the present study, the cumulative risk of HCC in patients with cirrhosis was investigated.

METHODS

A total of 401 patients were registered from April 1977 and followed for a mean of 4.4 years. Of 401 patients, 255 (64%) were tested for hepatitis B surface antigen (HBsAg) and antibody (anti-) to the hepatitis C virus (HCV); 87 (34%) patients were positive for HBsAg but were negative for anti-HCV (hepatitis B virus [HBV] group), 126 (49%) were negative for HBsAg but were positive for anti-HCV (HCV group), 10 (4%) were positive for both and 32 (13%) were negative for both (non-B non-C group).

RESULTS

By the end of March 1993, HCC was diagnosed in 127 (31.6%) patients. The cumulative risk of HCC in the HCV group was slightly higher than that in HBV group (P = 0.3, 5-year risk: 36.9 versus 21.2%). In contrast, the rate was significantly lower in the non-B non-C group than in the HBV or HCV groups (P < 0.05 and P < 0.01, respectively, 5 year risk: 12.4%).

CONCLUSIONS

These results suggest that not only HBV infection but also HCV infection increase the risk for HCC in patients with cirrhosis.

Genotype distribution of hepatitis C virus infection in Taiwan

To investigate the prevalence of genotype distribution of hepatitis C virus (HCV) infection in Taiwan, genotypes were identified in 122 (36 anti-HCV-positive blood donors, 44 anti-HCV-positive aborigines, 28 hemodialysis patients, and 14 patients with chronic liver diseases) of 280 subjects, using polymerase chain reaction by Okamoto's type-specific primer method. Type II was the dominant (66.7%) type among anti-HCV-positive blood donors, followed by type III and type IV with the same percentages (16.7%), while none of type I was detected. The prevalence of genotype distribution were 75.0%, 81.1%, and 64.3% for type II, 4.6%, 17.9%, and 21.4% for type III, 13.6%, 0%, and 7.1% for type IV, for the aborigines, hemodialysis, and chronic liver diseases groups, respectively. Four subjects revealed mixed infections by two different genotypes: two cases of II and III; and each one case of II and IV, and III and IV. Diverse genotype distributions in two hemodialysis groups disclose the existence of obvious regional differences even within a region. The results reveal the highest prevalence of type II as in Japan. However, there is a higher prevalence rate of type IV than in Japan.

Hepatitis C virus genotypes, reactivity to recombinant immunoblot assay 2 antigens and liver disease

To clarify the relationship between hepatitis C virus (HCV) genotypes and liver disease, we typed HCV genomes in the sera of 151 blood donors, 180 patients with type C chronic liver disease (CLD), and 30 haemophiliacs residing in Hiroshima, Japan. All of the subjects were positive for anti-HCV and HCV-RNA, and were examined for seroreactivity to HCV-specific antigens. The HCV genotypes were determined by polymerase chain reaction (PCR) with type-specific primers deduced from the putative core region of the HCV genome. Significantly more (P < 0.001) type III HCV was found in the samples from the CLD patients (80%) than in those from the blood donors (55%). Significantly more (P < 0.001) type III HCV was found in the samples from the blood donors (29.1%) than in those from the CLD patients (11.7%). There was no significant difference in the distribution of the HCV types among the patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma. A four-antigen recombinant immunoblot assay (RIBA-2) assay was used to compare the serum samples for their reactivity to a range of structural and nonstructural peptides specific for HCV (5-1-1, C100-3, C33c, and C22-3). The frequency of seropositivity to 5-1-1 and C100-3 was significantly higher (P < 0.001) in type II HCV-infected blood donors than in type III HCV-infected donors (68.2% and 65.9% vs. 4.5% and 22.7%, respectively). Among the type III HCV-infected individuals, the CLD patients had a significantly higher (P < 0.01) frequency of seropositivity to 5-1-1 than the blood donors (33.3% vs. 4.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus genotypes in France: comparison of clinical features of patients infected with HCV type I and type II

Two major hepatitis C virus genotypes, F1 and F2, corresponding to hepatitis C virus type I and type II respectively, were found in France. To investigate the correlation between infection with these genotypes (F1 and F2) and clinical features of patients, serum samples proven to be hepatitis C virus positive by polymerase chain reaction amplification on 5' non-coding region were further amplified in the NS3 region with nested polymerase chain reaction. The NS3-polymerase chain reaction products were Southern blotted and hybridized with specific probes to identify the genotype of hepatitis C virus. Of 70 samples 64 were NS3-polymerase chain reaction positive. Twenty-eight (40%) samples were hepatitis C virus type I (F1) and 34 (49%) were hepatitis C virus type II (F2), while one sample (HB) hybridized with both probes and another (HN) hybridized with neither. Some samples were sequenced, with results consistent with those of hybridization. The HB sample was related more to hepatitis C virus type II than to type I and the HN sample was divergent from both type I and type II genotypes. Clinical profiles of patients infected with hepatitis C virus type I and type II were compared. Type I infected patients were younger (p < 0.01) and more often male (p < 0.05) than those of the type II group. Nine of 28 patients in the type I infected group had a history of drug abuse, whereas none did in the type II group. Five of 22 (23%) type I infected patients and 19 of 32 (59%) type II infected patients had cirrhosis (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Posttransfusion hepatitis C virus infection in children

Hepatitis C virus (HCV) infection was investigated retrospectively and prospectively in children who had open heart surgery. The retrospective study included 196 patients who had open heart surgery 2 to 6 years before enrollment and were regularly followed. Antibody to HCV was detected in eight cases, and seven of these eight patients had viremia caused by HCV infection. The other patient's anti-HCV titer gradually decreased and HCV ribonucleic acid was absent throughout the course. Four of these eight had persistent viral replication without clinical evidence of hepatitis; the other three had viremia and chronic hepatitis. The HCV infection rate in the retrospective study group was about 4%. The HCV was of genotype 2 in five cases and of genotype 3 in two cases. The clinical outcome was not related to sex, age, amount of transfusion, or HCV genotype. For the prospective study, we enrolled 94 patients. Of the 56 enrolled after the initiation of anti-HCV screening in the blood bank, none was infected by HCV. Of the 94 patients, 38 were enrolled before screening; 4 had abnormal liver function 1 to 3 months after operation, and 2 were infected with HCV. One patient had an acute but resolving course; the other had persistent anti-HCV and HCV viremia, although the liver function test results returned to the normal range. The HCV in both cases belonged to genotype 2. We conclude that in Taiwan the seroconversion rate of HCV in children who underwent open heart surgery was 4% to 5%. Anti-HCV screening in donor blood significantly decreased the incidence of posttransfusion hepatitis C.

Geographical distribution of hepatitis C virus genotypes in blood donors: an international collaborative survey

The frequency of infection with the six classified major genotypes of hepatitis C virus (HCV) was investigated in 447 infected volunteer blood donors from the following nine countries: Scotland, Finland, The Netherlands, Hungary, Australia, Egypt, Japan, Hong Kong, and Taiwan. Viral sequences in plasma from blood donors infected with HCV were amplified in the 5'-noncoding region and were typed by restriction fragment length polymorphism analysis. Electrophoresis of DNA fragments produced by cleavage with HaeIII-RsaI and ScrFI-HinfI allowed HCV types 1 (or 5), 2, 3, 4, and 6 to be identified. Further analysis with MvaI-HinfI allowed sequences of the type 5 genotype to be distinguished from sequences of the type 1 genotype. Types 1, 2, and 3 accounted for almost all infections in donors from Scotland, Finland, The Netherlands, and Australia. Types 2 and 3 were not found in the eastern European country (Hungary), where all but one of the donors were infected with type 1. Donors from Japan and Taiwan were infected only with type 1 or 2, while types 1, 2, and 6 were found in those from Hong Kong. HCV infection among Egyptians was almost always by type 4. Donors infected with HCV type 1 showed broad serological reactivity with all four antigens of the second generation Chiron RIBA-2 assay (Chiron Corporation, Emeryville, Calif.), while infection with divergent HCV genotypes elicited antibodies mainly reactive to c22-3 and c33c. Reactivities with antibodies 5-1-1 and c100-3 were infrequent and were generally weak, irrespective of the geographical origin of the donor. Because the envelope region of HCV is even more variable than the NS-4 region, it is likely that vaccines based on these proteins need to be multivalent and perhaps specifically adapted for different geographical regions.

Genotypes of hepatitis C virus in Guangxi province, southern China

Hepatitis C virus (HCV) has been subdivided into at least four genotypes, and the prevalence of each genotype has been reported to differ widely in different countries. Of 304 patients with chronic liver diseases (68 with chronic hepatitis, 50 with liver cirrhosis and 186 with hepatocellular carcinoma) from Guangxi Province in southern China, only 9 (3.0%) had antibodies to HCV as determined by a second-generation enzyme immunoassay with a cut-off index of 2.0 or more. The HCV genotypes of these nine cases were examined using polymerase chain reaction with type-specific primers deduced from putative core gene. Seven of the nine cases had type II infection and the other two cases showed double infection with types II and IV. These findings indicate that the predominant HCV genotype in the Guangxi area is type II, as is the case in Japan, although the prevalence of HCV infection in patients with chronic liver diseases is much lower.

Hepatitis C virus genotypes are not responsible for development of serious liver disease

Although hepatitis C virus (HCV) is known to have at least four kinds of genotypes, no clear relationship has yet been established between the genotype and the severity of liver disease. Therefore, we determined HCV genotypes in sera of 251 Japanese patients with type C chronic liver disease, using polymerase chain reactions with six independent primers. One set of primers and a probe derived from 5'-noncoding region of HC-J1 was supposed to detect all four genotypes, while the other five were devised to detect each of the genotypes. Among the patients, the major genotype was type II (69%) and the second most common was type III (18%). Type IV was found in 7%, while none had type I genotype. There was no significant difference in the distribution of any genotype among different stages of liver disease, although the ratio of type II to type III tended to be higher in the group of cirrhosis and hepatocellular carcinoma than in the chronic hepatitis group (5.5 vs 3.0). The amounts of HCV RNA were significantly greater in patients with type II (P < 0.001) compared with those with types III and IV. However, HCV concentrations of each genotype were not associated with the disease status. These results suggest that HCV genotypes are unlikely to be responsible for the development of more serious liver disease.

Comparison of hepatitis C virus strains obtained from hemodialysis patients

To understand what genotypes of hepatitis C virus (HCV) exist in Taiwan, we chose the non-structure 5 (NS5) region of the HCV genome for the target area of reverse transcription-polymerase chain reaction (RT-PCR) to detect HCV RNA from sera of hemodialysis patients. Of 39 serum samples which were positive for the HCV antibody among 87 samples from hemodialysis patients, 12 (antibody against HCV core protein, OD > 2) were examined by the RT-PCR. The plasmid pUC19 was used to clone HCV cDNAs in the NS5 region (401 bp) derived from 11 serum samples which were positive for HCV RNA. Sequence analyses of individual clone of these 11 amplified cDNA fragments were performed. Dr. Cha's classification (16) suggested that two genotypes of HCV were found in these serum samples; type II (2/18.2%) and type III (9/81.8%). Our study indicates also that NS5 is an adequate target region to differentiate HCV strains derived from different patients in the same hospital. The analysis of the amplified cDNA in the NS5 region of the HCV genome will therefore provide suitable information to perform a molecular epidemiological study on the transmission routes of this important virus infection.

Polymerase chain reaction and transfusion microbiology

Polymerase chain reaction (PCR) involves alternate denaturing and re-annealing of DNA in test samples in the presence of appropriate oligonucleotide primers complementary to opposite strands of the target DNA together with a heat-stable DNA polymerase, Mg2+ and the four nucleotide triphosphates. DNA target segments can be 'amplified' ten-millionfold by 25-35 such cycles. Even greater amplification (approximately 10(12)-fold) with enhanced specificity can be obtained by a second set of amplification cycles using a further pair of 'nested' primers sited within the DNA sequence defined by the original primers. PCR can be applied to the study of the whole range of transfusion-transmitted infections, both plasma and cell associated; RNA viruses can be analyzed if a DNA copy is made from the viral RNA by treatment with reverse transcriptase. In a transfusion context, the retroviruses (HIV-1, HIV-2, HTLV-I, HTLV-II), HCV and HBV have been the viruses most intensively subjected to PCR analysis. The advantages of PCR in this context include its ability to detect virus during the 'window period' or seronegative stages of infections and its value as a marker for viraemia and for the detection of viruses in products made from large pools of plasma. True immunity may also be differentiated from persistent infection in the presence of antibody. Similarly, PCR can overcome problems of diagnosis of acute infection caused by the presence of passively transferred antibody. Detailed strain differentiation is also possible by PCR, in conjunction with sequencing or with the aid of restriction endonucleases.(ABSTRACT TRUNCATED AT 250 WORDS)