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PubMed2000

Hepatitis C virus genotypes in a non-cirrhotic Italian population with chronic hepatitis C: correlation with clinical, virological and histological parameters. Results of a prospective multicentre study.

To identify correlations between the distribution of hepatitis C virus (HCV) genotypes and demographic, pathological and virological parameters of HCV-infected patients, we prospectively recruited 650 patients with biopsy-proven chronic hepatitis C without histological aspects of cirrhosis; none had been treated with antiviral therapy. Data regarding gender, age, mode of HCV transmission, alanine aminotransferase (ALT) and HCV RNA levels, immunoglobulin M (IgM) anticore values, liver histology and histological activity were obtained from each patient and correlated on multivariate analysis with infecting HCV genotype. Fifty-five per cent of the patients were infected with HCV genotype 1, 20% with HCV genotype 2, 18% with HCV genotype 3 and 7% with HCV genotype 4. Non-transfusional HCV transmission, low ALT levels, IgM anticore reactivity and a low histological grading score were independent variables associated with HCV genotype 1. Older age, female gender, post-transfusional transmission and a high histological grading score were related to HCV genotype 2, whilst younger age, history of current/previous drug abuse, high ALT values, low IgM anticore reactivity and high viraemic levels were associated with HCV genotype 3. History of illicit use of intravenous drugs and low HCV RNA levels were the only independent variables correlated with HCV genotype 4. Genotype 1 remains predominant in Italy but the prevalence of HCV genotypes is changing in relation to age and mode of transmission: Italian patients with HCV genotype 3 are younger and exhibit higher levels of ALT and HCV RNA than patients with other genotypes.

Adolescent↗
PubMed2002

Epidemiological changes in hepatitis C virus genotypes in France: evidence in intravenous drug users.

Hepatitis C virus (HCV) genotypes are distributed differently depending on geography and route of infection. We characterized the distribution of genotypes in a large cohort of patients with chronic hepatitis C in the South-east of France and evaluated the relative prevalence according to time of acquisition. One thousand, one hundred-and-eighty-three patients who were anti-HCV-positive were studied. HCV genotype distribution has changed significantly from the 1960s to 2000. The prevalence of genotype 1b decreased from 47% before 1978 to 18.8% in the 1990s while the prevalence of genotype 1a and 3a increased during the same period from 18% and 15.3% to 28.8% and 26.3%, respectively. The logistic regression model showed that genotype 1a was significantly more common in patients infected through intravenous drug injection odds ratio ((OR): 2.08, P < 0.01) and after 1990 (OR: 1.98, P < 0.05). Genotype 1b was significantly less frequent in patients infected through intravenous drug injection (OR: 0.17, P < 0.001) and has decreased since 1978 (OR: 0.27, P < 0.001). Genotype 3a was independently associated with intravenous drug injection (OR: 6.1, P < 0.001) and tattooing (OR: 8.01, P < 0.001) and was more frequent in the 1979-90 period (OR: 2.05 and 1.74, P < 0.001 and P < 0.05). Our results show a modification of HCV genotypes distribution over the last four decades due to an increase of intravenous drug use (IVDU) contamination and an evolution of HCV genotypes distribution only in IVDU population characterized by a decrease of genotype 1b, an increase of genotype 3a from 1970 to 1990 and a higher increase of genotype 1a which is currently the predominant genotype in our population.

Adult↗
PubMed2002

Hepatitis B virus genotypes and clinical manifestation among hepatitis B carriers in Thailand.

BACKGROUND: Hepatitis B virus (HBV) genotypes have distinct geographic distributions. The aim of the present study was to evaluate the distribution of HBV genotypes and their clinical relevance in Thailand. METHODS: Hepatitis B virus genotypes among 107 hepatitis B carriers residing in Thailand were evaluated using serologic and genetic methods. They were clinically classified into asymptomatic carriers with normal serum alanine transaminase (ALT) levels and patients with chronic liver disease, such as those with chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). RESULTS: Hepatitis B virus genotype distribution among the 107 patients was 25.2% for genotype B, 72.0% for genotype C and 2.8% for genotype D. The serum ALT levels, HBV-DNA and hepatitis B e antigen positivity were significantly higher in carriers infected with genotype C HBV than in those infected with genotype B (P < 0.05). The proportion of genotype B HBV was higher in asymptomatic carriers than in patients with CH and those who developed liver disease, such as LC and HCC (45.5, 16.9 and 25.0%, respectively; P < 0.05). In contrast, the proportion of genotype C HBV was higher in patients who developed liver disease and CH than in asymptomatic carriers (68.7, 83.0 and 50.0%, respectively; P < 0.05). Phylogenetic analysis based on entire genome sequences revealed three HBV isolates, which were classified into a subgroup of genotype C in isolates from South-East Asian countries. CONCLUSIONS: Genotypes B and C are the predominant types among hepatitis B carriers residing in Thailand and those genotypes influence the clinical manifestation in carriers with chronic hepatitis B infection.

Adult↗
PubMed1999

Chronic hepatitis C in Sweden: genotype distribution over time in different epidemiological settings.

Hepatitis C virus (HCV) strains are divided into 6 genotypes and several subtypes. Recent studies reported a change in the relative frequency of genotypes within certain regions. We studied the HCV genotype in 312 Swedish patients with chronic hepatitis C, using a core region primer-specific PCR, and grouped the patients according to parenteral risk factors. The date of infection could be estimated in 127 cases. Genotypes 1a (35%) and 3 (31%) were the most common genotypes, followed by genotype 2 (17%), while only 6% had genotype 1b. Genotype 3 was relatively more frequent among subjects infected sexually or by intravenous drug use. The genotype distribution was different from that in studies from other parts of the world, with a lower frequency of genotype 1 (especially 1b) and a higher frequency of genotype 3. The frequency of genotype 1b has decreased and genotype 3 increased over time. The reasons for a different distribution of genotypes in Sweden, compared with other countries, might be a relatively recent introduction of HCV into the population, or a different pattern of transmission.

Adult↗
PubMed2004

Distribution of hepatitis B virus genotypes in blood donors and chronically infected patients in a tertiary care hospital in southern India.

Hepatitis B virus (HBV) genotypes differ in their potential for causing disease. Consecutive patients with chronic HBV infection (CHBV) (n=122) and blood donors (n=67) positive for hepatitis B surface antigen and HBV DNA were genotyped using polymerase chain reaction-restriction fragment-length polymorphism. The ratio of male to female subjects was significantly higher in the blood donor group than in the group of patients with CHBV (P=.0004). Among patients with CHBV, genotype D was detected in 57.3%, genotype A was detected in 18%, and genotype C was detected in 11.5%. Only genotypes D and A were detected in blood donors. The difference between the detection rate of genotype C in patients with CHBV and in blood donors was significant (11.5% vs. 0%; P=.009). Patients with CHBV who had genotype C had higher alanine transaminase (ALT) levels than those who had genotype A (P=.044) or genotype D (P=.014). Detection of genotype C in patients with CHBV and the association of genotype C with higher ALT levels may predict that this genotype has a greater potential for causing disease than other genotypes.

Adult↗
PubMed2000

Relationship between genotypes of hepatitis C virus and histopathological manifestations in chronic hepatitis C patients.

OBJECTIVE: The aim of this study was to assess the relationship between HCV genotype and histological liver injury. DESIGN: Prospective study on a cohort of patients with biopsy proven chronic hepatitis C. SETTING: University medical centre. PARTICIPANTS: Enrolled were 324 consecutive patients (male 197, median age 52 years, range 19-68; chronic hepatitis, 224; cirrhosis, 100). METHODS: HCV genotype was determined by the INNO LiPA assay and HCV RNA levels by the bDNA assay. The histological features were scored according to the histology activity index. RESULTS: The distribution of HCV genotypes was 1a, 4.6%; 1b, 52.4%; 2a/c, 27%; 3a, 8%; 4, 2%; mixed, 6%. Serum HCV RNA levels were similar for all genotypes. There was no difference in the distribution of HCV genotypes between patients with chronic hepatitis and those with cirrhosis. Patients with genotype 1b and those with type 2a/c showed a similar prevalence of cases of cirrhosis (33% versus 31%, respectively). In addition, in a subgroup of 102 patients with an established date of infection, the progression to cirrhosis occurred with a similar length of time for HCV type 1b and 2a/c (median 16 versus 15 years, respectively). Patients with HCV genotype 2a/c or mixed genotype showed a higher histology activity index than those with type 1b (P< 0.01), whereas there was no difference in the fibrosis score for the different genotypes. Patients with genotype 3a showed a significantly higher prevalence of steatosis compared to those infected with other genotypes. Alanine aminotransferase (ALT) values were higher in patients with HCV type 2a/c, 3a and mixed genotype than those with type 1 (P < 0.002). CONCLUSIONS: The data indicate that there is no association between a particular HCV genotype and the progression to cirrhosis, and that specific genotypes are associated with distinct histopathological and biochemical manifestations although none of them is correlated with an increase of the fibrosis stage.

Adult↗
PubMed2005

Geographic distribution, virologic and clinical characteristics of hepatitis B virus genotypes in China.

The significance of hepatitis B virus (HBV) genotypes for the heterogeneity of chronic HBV infection and severity of liver disease is not well understood. The aim of this study was to determine the distribution and virologic characteristics of HBV genotypes in China and possible association with the diversity of liver disease. The study includes 1096 chronic HBV carriers from nine provinces in China. We collected clinical and laboratory data and analysed the HBV strains in sera by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and nucleotide sequencing techniques. The most common HBV genotypes were B (41%) and C (53%), while genotypes A and D were also found. A North-South divide was identified in genotype B and C distribution - genotype C was predominant in northern China, while genotype B was more prevalent in southern provinces. Patients with genotype B were younger than those with genotype C, and had a lower prevalence of HBeAg - 65%vs 72%, respectively (P = 0.03). However, the severity of liver disease did not differ significantly between patients infected with genotype B or C - neither when comparing liver function tests (1024 patients), nor hepatic inflammation and fibrosis (264 patients). Amongst 47 patients with genotype D (by PCR-RFLP), 37 (79%) were infected with a new subtype (designated Dc), having a recombination fragment from genotype C precore/core region. This is the first large-scale HBV genotype study from China and convincing documentation of the North-to-South gradient of genotypes C vs B in this country. HBV DNA recombination over the surface and precore/core genes increases the diversity of HBV strains and may have diagnostic and clinical implications.

Adult↗
PubMed2006

Multicentre study of hepatitis B virus genotypes in France: correlation with liver fibrosis and hepatitis B e antigen status.

The clinical significance of hepatitis B virus (HBV) genotypes is still under debate. The aims of this study were to assess the distribution of HBV genotypes in France and to identify the associations between HBV genotypes and patient demographics, severity of liver disease and HBeAg status in patients referred to tertiary care centres. This was a French, multicentre, retrospective study on 262 patients with chronic HBV infection. HBV genotypes were determined using INNO-LiPA. Liver fibrosis damage was evaluated by histological analysis of biopsy samples. Patients were mainly male (74%), of Caucasian (65%), Asian (17%) or African (18%) ethnicity and 36% were HBeAg positive. All A-G genotypes were found, the most frequent being genotypes D (27%) and A (24%), followed by E (13%) and C (12%), and B (7%). Mixed genotypes were detected in 16% of the cases. Genotype A was associated with sexual contact (P < 0.001) and genotype D with transfusion (P < 0.001) and HBe antibody positivity (P = 0.03).The distribution of HBV genotypes differed with regard to the ethnicity, and may reflect migration patterns. Genotypes A and D were the most frequent in France. Genotype A was associated with HBeAg positivity and genotype D with HBe antibody positivity. In our European patients, we find no clear association between a given HBV genotype and liver disease severity.

Adult↗
PubMed1997

Hepatitis C virus genotypes in a cohort of Australian blood donors and haemophiliac and liver transplant patients.

The aim of the present study was to characterize hepatitis C virus (HCV) genotypes using the INNO-LiPA HCV line probe assay and direct sequencing from three different HCV-RNA-positive (serum) groups: (i) blood donors (n = 59); (ii) haemophiliacs (n = 43); and (iii) patients undergoing liver transplantation (n = 26). Of 128 HCV-RNA-positive samples, 74 (58%) were genotype 1. Of these, 41 were genotype 1a, 32 were genotype 1b and one was genotype 1 indeterminate. Of the remaining 54 samples, seven (5%) were genotype 2a, two (2%) were genotype 2b, 26 (20%) were genotype 3a, three (2%) were genotype 4a, while 16 (12.5%) were of a mixed genotype. There was no significant difference between the three groups with regard to the prevalence of any specific genotype. However, in blood donors and haemophiliac patients there was a statistically significant difference in the occurrence of genotype 3a in patients with elevated alanine aminotransferase (ALT) levels (30.3%) compared with those patients with persistently normal ALT levels (5.6%; P = 0.004; chi 2). Genotype 3a was also uncommon in liver transplant patients (one of 14) with "sporadic' HCV infection. Genotype 4a was detected only in liver transplant patients. These patients had originated from Egypt (n = 1), Italy (n = 1) and Romania (n = 1).

Adult↗
PubMed2002

Clinical and virological aspects of blood donors infected with hepatitis B virus genotypes B and C.

Pathogenic and therapeutic differences among hepatitis B virus (HBV) genotypes have been documented. However, the association of virological characteristics with clinical differences among HBV genotypes remains unclear. We therefore studied the clinical and virological characteristics of Taiwanese volunteer blood donors infected with HBV genotypes B and C. HBV genotypes were determined in 300 candidate blood donors positive for HBV surface antigen (HBsAg), and sequences of the precore gene of the HBV genome were determined in 50 HBV e antigen (HBeAg)-positive and 50 HBeAg-negative blood donors. Of 300 HBsAg-positive blood donors, 10% had elevated serum aminotransferase levels and 27% were positive for HBeAg. HBV genotype distribution in 264 viremic carriers was as follows: B, 221 (83.7%); C, 39 (14.8%); F, 1 (0.4%); and mixed infection, 3 (1.1%). Blood donors with genotype C infection tended to have a higher frequency of HBeAg positivity and a higher serum HBV DNA level than those with genotype B infection. The frequency of precore stop codon mutation was significantly higher in HBeAg-negative blood donors than HBeAg-positive ones, irrespective of HBV genotypes. Meanwhile, only 5% of blood donors with genotype C infection had C-1858 strains. In conclusion, mixed infection of HBV genotypes indeed occurs, and genotype C has a higher serum HBV DNA level than genotype B. Precore stop codon mutation is common in HBeAg-negative HBV carriers, irrespective of HBV genotypes. In contrast, precore C-1858 strains are rarely identified in Taiwanese HBV genotype C.

Adult↗
PubMed2006

222 base pairs in NS5B region and the determination of hepatitis C virus genotype 6.

OBJECTIVE: The present study was performed to genotype hepatitis C virus (HCV) by direct sequencing of a 222-bp nucleotide in the NS5B region and comparing the results with those of direct sequencing in the core region. We investigated a new region for HCV genotyping which gave the best performance to discriminate HCV genotype 6a, the unique genotype found in Southeast Asia. METHODS: Plasma samples taken from 57 HCV-infected blood donors were used in this study. RT-PCR products were amplified using primers located in the NS5B region. The 222-bp PCR products were purified and sequenced. The genotype of HCV isolates were obtained by phylogenetic analysis and compared with HCV reference strains stored in the GenBank database. The HCV sequences clustering in the same node were considered to be of the same genotype. RESULTS: Thirty-one, 22 and 4 samples of HCV genotype 3a, 1a and 1b, respectively, were analyzed by this method. Upon comparison with genotyping in the core region, 86 and 14% of the samples yielded concordant and discordant genotype results, respectively. The majority of discordant results (63%; 5 of 8) was observed with HCV genotype 6a which yielded 6a upon core sequencing as opposed to 1a or 3a upon NS5B sequencing. CONCLUSION: HCV genotype 6a obtained by direct sequencing in the core region could not be unequivocally arrived at by sequencing 222 bp in the NS5B region. Hence, sequencing in the core region is preferable for genotyping our specimens, even though longer PCR products are required as this method enables discrimination between genotype 6a and the remaining genotypes.

Base Pairing↗
PubMed2004

Contamination of coagulation factor concentrates with human parvovirus B19 genotype 1 and 2.

Human parvovirus B19 (B19) DNA has frequently been detected in plasma-derived coagulation factor concentrates. Furthermore, transmission of B19 infection was observed, indicating presence of the infectious virus despite routine viral inactivation/removal procedures during the manufacturing process. Recently, human parvovirus DNA isolates, variant from B19, have been identified resulting in classification of B19 virus into three distinct genotypes, with all viruses previously classified as B19 belonging to genotype 1. So far, there is no information available on contamination of clotting factor concentrates with genotype 2. Therefore, we analysed 202 different factor concentrate lots for genotype 1 and 2 DNA by PCR. Analysis of one hundred eighty-one lots representing 13 different products, administered over the last three years, was compared to 21 lots (8 products) used until the early 1980s which had not been treated by viral inactivation procedures. Genotype 1 DNA was detected in 77/181 (42.5%) currently administered lots, and 17/21 (81%) previously used lots. The level of genotype 1 DNA contamination was similar in currently and previously administered concentrates. Genotype 2 DNA was found in 5/202 (2.5%) lots, all of which were co-contaminated with genotype 1 DNA. DNA sequence analysis showed that the PCR-double positive concentrates contained typical genotype 1 and genotype 2 DNA. Because genotype 2 appears to cause a similar spectrum of diseases as genotype 1, simultaneous detection of genotype 2 by nucleic acid amplification testing (NAT), now widely applied to plasma pools for genotype 1, would give an added level of safety to blood products.

Blood Coagulation Factors↗
PubMedDate not supplied

Using genotype probabilities in survival analysis: a scrapie case.

The objective was to evaluate the potential use of genotype probabilities to handle records of non-genotyped animals in the context of survival analysis. To do so, the risks associated with the PrP genotype and other transmission factors in relation to clinical scrapie were estimated. Data from 4049 Romanov sheep affected by natural scrapie were analyzed using survival analysis techniques. The original data set included 1310 animals with missing genotypes; five of those had uncensored records. Different missing genotype-information patterns were simulated for uncensored and censored records. Three strategies differing in the way genotype information was handled were tested. Firstly, records with unknown genotypes were discarded (P1); secondly, those records were grouped in an unknown class (P2). Finally the probabilities of genotypes were assigned (P3). Whatever the strategy, the ranking of relative risks for the most susceptible genotypes (VRQ-VRQ, ARQ-VRQ and ARQ-ARQ) was similar even when the non-genotyped animals were not a negligible part of uncensored records. However, P3 had a more efficient way of handling missing genotype information. As compared to P1, either P2 or P3 avoided discarding the records of non-genotyped animals; however, P3 eliminated the unknown class and the risk associated with this group. Genotype probabilities were shown to be a useful technique to handle records of individuals with unknown genotype.

Animals↗
PubMed2005

Silhouette scores for assessment of SNP genotype clusters.

BACKGROUND: High-throughput genotyping of single nucleotide polymorphisms (SNPs) generates large amounts of data. In many SNP genotyping assays, the genotype assignment is based on scatter plots of signals corresponding to the two SNP alleles. In a robust assay the three clusters that define the genotypes are well separated and the distances between the data points within a cluster are short. "Silhouettes" is a graphical aid for interpretation and validation of data clusters that provides a measure of how well a data point was classified when it was assigned to a cluster. Thus "Silhouettes" can potentially be used as a quality measure for SNP genotyping results and for objective comparison of the performance of SNP assays at different circumstances. RESULTS: We created a program (ClusterA) for calculating "Silhouette scores", and applied it to assess the quality of SNP genotype clusters obtained by single nucleotide primer extension ("minisequencing") in the Tag-microarray format. A Silhouette score condenses the quality of the genotype assignment for each SNP assay into a single numeric value, which ranges from 1.0, when the genotype assignment is unequivocal, down to -1.0, when the genotype assignment has been arbitrary. In the present study we applied Silhouette scores to compare the performance of four DNA polymerases in our minisequencing system by analyzing 26 SNPs in both DNA polarities in 16 DNA samples. We found Silhouettes to provide a relevant measure for the quality of SNP assays at different reaction conditions, illustrated by the four DNA polymerases here. According to our result, the genotypes can be unequivocally assigned without manual inspection when the Silhouette score for a SNP assay is > 0.65. All four DNA polymerases performed satisfactorily in our Tag-array minisequencing system. CONCLUSION: "Silhouette scores" for assessing the quality of SNP genotyping clusters is convenient for evaluating the quality of SNP genotype assignment, and provides an objective, numeric measure for comparing the performance of SNP assays. The program we created for calculating Silhouette scores is freely available, and can be used for quality assessment of the results from all genotyping systems, where the genotypes are assigned by cluster analysis using scatter plots.

Alleles↗
PubMed2006

Hepatitis B genotypes: relation to clinical outcome in patients with chronic hepatitis B in Saudi Arabia.

AIM: To identify the most common hepatitis B virus (HBV) genotype in Saudi Arabia, and correlate the prevailing genotypes with the clinical outcome of patients. METHODS: Patients were consecutively recruited from the hepatology clinics of two tertiary care referral centers. Patients were categorized into 4 different groups: group 1, patients with hepatitis B and normal liver enzymes; group 2, patients with hepatitis B and abnormal liver enzymes but without cirrhosis; group 3, patients with hepatitis B and liver cirrhosis; group 4, patients with hepatitis B and hepatocellular carcinoma. All patients had a positive hepatitis B surface antigen (HBsAg). Genotyping of HBV was performed by nested PCR-mediated amplification of the target sequence and hybridization with sequence-specific oligonucleotides. RESULTS: Seventy patients were enrolled in this study. They were predominantly male (72.9%) in their mid-forty's (mean age 47 years). Forty-nine (70%) patients were hepatitis B envelope antigen (HBeAg) negative. The majority of patients (64%) acquired HBV through unknown risk factors. Hepatitis B genotyping revealed that 57 patients (81.4%) were genotype D, 1 patient (1.4%) had genotype A, 1 patient (1.4%) had genotype C, and 4 patients (5.7%) had genotype E, while 7 patients (10%) had mixed genotype (4 patients ADG, 1 patient DE, 1 patient DF, and 1 patient ADFG). Based on univariate analysis of genotype D patients, significant predictors of advanced liver disease were age, gender, aspartate transaminase, alanine transaminase, albumin, bilirubin, and alkaline phosphatase (all P < 0.001). In multivariate analysis decreased hemoglobin (r = -0.05; 95% CI: -0.08 to -0.03; P = 0.001) and albumin levels (r = -0.004; 95% CI: -0.007 to -0.001; P = 0.002) were highly significant predictors of advanced liver disease. In patients with HBV genotype D, HBeAg negativity was found to increase across advancing stages of liver disease (P = 0.024). CONCLUSION: This study highlights that the vast majority of Saudi patients with chronic hepatitis B have genotype D. No correlation could be observed between the different genotypes and epidemiological or clinical factors. The relationship between genotype D and HBeAg status in terms of disease severity needs to be further elucidated in larger longitudinal studies.

Adult↗
PubMed2002

Clinical outcomes of hepatitis B virus (HBV) genotypes B and C in Japanese patients with chronic HBV infection.

The aims of this retrospective survey were to determine the epidemiologic distribution of hepatitis B virus (HBV) genotypes and analyze the genotype-related clinical differences among Japanese patients with chronic HBV infection. The 158 surveyed patients with chronic HBV infection lived in Fukuoka and Okinawa were serially tested for serum alanine aminotransferase (ALT) and hepatitis B e antigen (HBeAg). Follow-up was for a period of 10.8 +/- 6.4 years (mean +/- SD). The HBV genotypes were determined in sera by an enzyme-linked immunosorbent assay and detection of HBV DNA in serum was done by the transcription-mediated amplification-hybridization protection assay. Genotypes B and C were found in 58 (36.7%) and 100 (63.3%) of the patients, respectively. Genotype B was predominant in Okinawa (B = 86.9%, C = 13.1%), whereas genotype C was predominant in Fukuoka (B = 5.2%, C = 94.8%). The HBeAg positivity and ALT abnormality rates at the start of the observation period were significantly higher in patients with genotype C (66.0% and 84.0%) than in patients with genotype B (34.5% and 22.4%) (P < 0.05, respectively). The annual rate of spontaneous HBeAg disappearance in patients with genotype B was much higher than in patients with genotype C (8.38% versus 2.34%, respectively). Patients with genotype C who were continuously HBeAg negative from entry had a significantly higher ALT abnormality (58.8%) than those with genotype B (19.2%) (P < 0.05). Interestingly, patients with genotype C who became HBeAg negative after treatment with interferon had a high ALT abnormality (58.8%). All patients with an ALT abnormality were positive for HBV DNA in their serum. These findings indicate that patients with HBV genotype C have more severe liver deterioration because of the delay of HBeAg disappearance and continued HBV replication after HBeAg disappearance.

Adult↗
PubMed2004

[Genotyping and the quantification of hepatitis C virus by the melting curves in light cycler].

Detection of the HCV genome is crucial for diagnosis of HCV infection and for monitoring the efficacy of interferon treatment for patients with HCV. We developed a convenient screening test for HCV genotypes 1 and 2 based on the melting curve analysis with SYBER green I. Serum samples were drawn from 114 patients with known chronic HCV infection confirmed to be antibody-positive by immunoblot assay. A characteristic melting profile for each genotype was obtained by monitoring the fluorescence as the temperature increases through the melting point of the PCR product. Serum samples with HCV-RNA genotype (1b, 2a and 2b) were analyzed every test as standard samples and the genotype of unknown samples was determined by the comparison with the melting point of standard samples. Serum samples with known HCV-RNA genotype (1b, 2a and 2b) and HCV-RNA-negative sample were tested using the Light cycler system. The melting curve analysis indicated that melting points are 93.08 +/- 0.56 degrees C for genotype 1b (n = 63), 91.08 +/- 0.49 degrees C for genotype 2a (n = 33), and 91.77 +/- 0.28 degrees C for genotype 2b (n = 18). The melting points for genotypes 1b, 2a, and 2b differed by approximately 1 degree C in each other. The genotype was determined for all samples using Okamoto's method and Light cycler system, and both systems produced absolutely identical results for all the samples studied. Sixty-three of 114 were genotype 1b, 33 samples were genotype 2a, and 18 were genotype 2b. This melting curve analysis is a rapid and convenient screening test for differentiation of HCV genotypes 1 and 2.

Benzothiazoles↗
PubMed2006

Hepatitis B virus genotypes and response to antiviral therapy.

Hepatitis B virus (HBV) infection is an important health problem worldwide. The virus has been classified according to 8 genotypes (A-H) based on sequence divergence. Most genotypes have specific geographic distributions; genotypes A and D are prevalent in Western Europe and North America, and genotypes B and C are prevalent in East Asia and Oceania. Currently accepted treatment for chronic hepatitis B includes interferon alpha, or the nucleoside/nucleotide analogues lamivudine and adefovir. The impact of HBV genotypes on response to antiviral therapy has been studied. HBV genotypes D and C are associated with a lower rate of favorable response to interferon alpha therapy than genotypes A and B, respectively. A study in Germany suggested that the rate of resistance to lamivudine was higher in patients with HBV genotype A infection than in patients with genotype D infection. No difference in the risk of lamivudine resistance is found between patients with genotype B and patients with genotype C. In patients with genotype C infection, however, virological response is worse during lamivudine therapy, and is also less durable after the discontinuation of therapy than in patients with genotype B infection. Determining the genotype could be helpful for predicting the outcome of antiviral therapy in patients with chronic hepatitis B.

Adenine↗