A Preliminary Study On Gene Mutation Of HBV DNA In Patients With Fulminant Hepatitis B And HBV Genotyping In Henan

Hepatitis B is a kind of DNA virus. People who are infected with HBV could present with different clinical outcome: asymptomatic carriers, acute hepatitis, chronic hepatitis B, and fulminant hepatitis B. Patients with fulminant hepatitis B always develop severe liver disease and result in worse therapeutic effect and the mortality is very high. Yet, it's possible mechanisms are still unknown. Nowadays we think that the pathogeny plays an important role in the clinical course of fulminant hepatitis B besides the host's factors. HBV gene mutation is a kind of common phenomenon that could induce chronic and fulminant hepatitis B.Furthermore the genotype of HBV reflects the selection process behind gene variation.Furthermore ,it suggests that the genotypes of HBV have relation to the infection approach and the clinical course of hepatitis B.OBJECTIVE: (1)to study the CP and Pre-S gene variation in patients with fulminant hepatitis B and accordingly to investigate the relationship between HBV DNA gene variation and the occurrence of fulminant hepatitis B; (2) to investigate the proportion of the genotypes in chronic hepatitis B and fulminant hepatitis B in henan and to find the relationship between different genotypes, HBV gene mutation and the occurrence of fulminant hepatitis.METHOD: (1)HBV DNA extracted from fulminant hepatitis B patients weresubjected to polymerase chain reaction and then polyacrylamide gel electrophoresis. Three different kinds of PCR products were analyzed by gene sequencing method and specific computer software was used to analyze the homology of these gene sequences ￤ith specific primers and HBV DNA extracted from the serum of the fulminant hepatitis B and chronic hepatitis B patients, we amplified the objective gene using nested-PCR and analyzed the genotypes of every samples through agarose electrophoresis.RESULT: (1)we found the sequence hi the CP gene of 16 samples are of same length, but after polyacrylamide gel electrophoresis different length sequences in the Pre-S gene of 16 samples was detected. After analyzing the gene sequence, we found various kinds of gene variation apart from the apparent deletion mutation and the homology was more than 80% (2)All the samples from the fulminant hepatitis B were genotyped as B (100%). Among the samples from chronic hepatitis B, seven were genotyped as B (14%) and the other 43 samples were genotyped as B and C (86%).CONCLUSION: (1) The gene variation was randomly occurred in Pre-S gene of HBV DNA getted from patients with fulminant hepatitis B , especially in the right end Pre-S i ^ Pre-S2;we didn't find deletion mutation in the CP gene. Whether there was other characteristic gene variation occurred in other sequences of HBV DNA was unknown.(2) The most common viral genotype was B in the patients of henna with fulminant hepatitis B; B and C were the most prevalent genotypes in the patients with chronic hepatitis B. This suggested that the genotype B were associated with fulminant hepatitis B.(3) In patients with fulminant hepatitis B, the gene mutation occurred hi CP and Pre-S sequences had no specificity and HBV DNA was all genotyped as B. Further investigation is needed on the characteristics of gene mutation of other genotypes hi the patients with fulminant hepatitis B.