[Relationship between hepatitis B virus genotypes and basic core promoter/precore mutations in patients with severe hepatitis.].

BACKGROUND: To investigate the relationship between hepatitis B virus genotypes and basic core promoter (BCP)/precore mutations in patients with severe hepatitis. METHODS: HBV genotypes were determined by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 52 patients with severe hepatitis and 52 cases with chronic hepatitis B (CHB). Eight samples of genotypes B and C were randomly selected and their S gene was directly sequenced, and then their phylogenetic trees were analyzed. Fifteen samples of each of genotypes B and C were randomly selected and their BCP and precore genes were directly sequenced with PCR, and then the relationship between genotypes and BCP(T1762/A1764)/precore (A1896) mutations were analyzed. RESULTS: Genotype B C and mixed genotypes (B and C) were detected in patients with severe hepatitis in Quanzhou area. Genotype B was the majority with a proportion 48.08% others had a proportion 30.77% and 17.31%, respectively. Genotype A, E and F were not detected. The percents of genotype C, mixed B and C in severe hepatitis were significantly higher than that in CHB. The double mutation in BCP (T1762/A1764) was significantly more frequent in severe hepatitis with genotype C than that in genotype B (P less than 0.05). However, there was no significant difference in the distribution of precore mutant with A1896 between genotype B and C patients (P greater than 0.05). CONCLUSION: Genotype C may induce more severe liver inflammation than that genotype B may do. Mixed genotypes B and C infection may be an important determinant of inducing severe hepatitis. The double mutation in BCP (T1762/A1764) was more common in severe hepatitis with genotype C than that with genotype B.