[Study on hepatitis C virus genotypes in Yantai district, Shandong province].

OBJECTIVE: To understand the hepatitis C virus (HCV) genotype distribution in Yantai district of Shandong province, and to explore whether the HCV genotypes was relevant to the injure of liver through the index of liver function. METHODS: Using specific PCR primers to amplify the HCV RNA 5' UTR/NS5B,then PCR products were sequenced by genetic analyzer. The genotypes were identified by alignment to the GenBank reference sequences and construction the phylogenetic tree of 5' UTR. RESULTS: Among 9 unpaid blood donors we detected two kinds of genotypes of 1b and 3a, respectively, 8 cases (88.9%) and 1 case (11.1%). Among 33 cases of hepatitis C patients we detected the 1b, 2a and 6a the three kinds of genotypes, respectively, 22 (66.7%), 10 (30.3%) and 1 (3.03%) cases. Subtype 1b is the advantage of popular genotype in HCV carriers from Yantai district, and the distribution of 1b was no significant difference in the different population (chi2 = 0.796, P = 0.373); The difference of indicator of liver damage in the different genotypes of subjects were significant (P < 0.05), the mean of ALT, AST of 2a-subtype carriers was significantly higher than the 1b-subtype population. CONCLUSIONS: The genetic diversity of HCV in Shandong Yantai district was presented. The main genotypes were 1b-subtype, and 3a and 6a-subtype was detected firstly. The genotype of HCV were relevant to the liver damage indicators, 2a-subtype hepatitis C virus infection in the liver cells may play an important role in the disease process.

[Detection and significance of gene variation in hepatitis B virus S region].

OBJECTIVE: To explore the variations of gene S in hepatitis B viruses of hepatitis B patients and provide experimental evidences for the mutation analysis of viral gene. METHODS: The virus DNA load in hepatitis B patient donors was detected by real-time polymerase chain reaction (PCR) and gene sequence analysis. And a comparison was made with standard strain by the software DNAstar. RESULTS: (1) Gene S was successfully amplified and sequenced in 15 hepatitis B patients. Three samples had I→T mutation at residue 126 in HBsAg "a" antigenic determinant. (2) Sixteen hepatitis B patients had 67 nucleotide mutations, including 14 residues in PreS1 and 6 residues in PreS2. Mutations nt 3036 T→C, nt 3039 T→G, nt 3066 C→T and L88V existed in PreS1 gene in all samples. CONCLUSION: HBV genome is susceptible to nucleotide mutations. Some residues have geographically restricted mutations in gene S region. And understanding the significance of these mutations may help clarify the pathogenesis of hepatitis B and provide new experimental evidence for its gene diagnosis and prevention.

[Detection and analysis of gene polymorphism in hepatitis B virus C region].

OBJECTIVE: To explore the variations of gene C in hepatitis B viruses between hepatitis B patients and healthy carriers, and provide experimental evidences for analysis of virus gene mutations acting on the virus material science and response of the body to the virus. METHODS: The virus DNA load in hepatitis B patients and healthy blood donors was investigated by real-time polymerase chain reaction (PCR). Gene sequence analysis was taken to detect gene polymorphism, and all the success samples were compaired with standard strain by DNAstar. RESULTS: (1)G Compared with standard strain, C region in all samples had mutations, there were 31 mutations in at least 2 samples (3 mutations in gene PreC and 28 mutations in gene C), including 9 missense mutations, 1 chain termination mutation and 21 synonymous mutation. Mutations nt 1827 c-->a and nt 2221 c-->t existed in all the samples, and most samples had 6 synonymous mutations. Four hepatitis B patients had mutation nt1896 g-->a, and another 4 patients had 2 mutations, namely, S87G and I97F (or 197L) in HBcAg CTL recognition episome. (2) The success ratio of amplification and sequencing of HBV DNA was closely associated with its copy numbers. In the present study, copy numbers of HBV DNA which were successfully amplified and sequenced were almost more than 40 193/ml. CONCLUSIONS: HBV genome were easily affected by nucleotide mutations, 2 residues had mutations in gene of C region, which is firstly reported, suggesting these mutations may be geographical restricted. Mutations in gene of C region may either change the structure and function of HBeAg and HBcAg, which may further induce the escape of immune clearance for HBV or influence the detection of HBsAg or HBeAg, which may creat new problems for the prevention, diagnosis and treatment of hepatitis B.