Relationship Between HBV Genotype, PRE-C Region Mutation And Pathogenetic Condition Of Chronic Hepatitis B

Objective: To make precise quantitation and distribution analysis of hepatitis B virus (HBV) genotypes in Chongqing. Explore the relationship between HBV genotype, mutation of precore region and outcomes of chronic hepatitis B.Methods: Real-Time Genotyping and Quantitative PCR (GQ-PCR) was used to genotype and quantitate the HBV strains. Retrospective analysis of the proportion of genotypes in different liver diseases; Mutation analysis of the sequenced precore region amplified by the nested PCR.Results: A total of 148(97.37%)out of the 152 strains were successfully genotyped. Among them, 109 patients (88 males and 21 females) had genotype B with quantity ranging from 4~12 log10copies/ml, and mean and standard deviation of 7.94±1.44log10copies/ml, 10 patients (6 males and 4 females) had genotype C with quantity ranging from 5~10 log10copies/ml, and mean and standard deviation of 8.12±1.64 log10copies/ml, 29 patients (24 males and 5 females) had mixtures of genotype B and C with quantity ranging from 4~10 log10copies/ml, and mean and standard deviation of 7.45±1.59 log10copies/ml. The detecting rates of genotype B, genotype C, and mixed genotype B and C were 73.65%( 74.58% in males, 70.00% in females), 6.76%( 5.08% in males, 13.30% in females), and 19.59%( 20.34% in males, 16.70% in females), respectively. Proportion of genotype B in the groups of liver cirrhosis, hepatocellular carcinoma, chronic severe hepatitis B and chronic hepatitis B were 38.53%, 12.84%, 33.03% and 15.60% respectively; proportion of genotype C in the groups above were 70.00%, 10.00%, 20.00% and 0 respectively; while proportion of mixed genotype B and C in the groups above were 62.07%, 6.90%, 20.69% and 10.34%. Compared with genotype B, mixed genotype B and C was more common in patients with liver cirrhosis(χ2=5.16, P<0.05), but no significance was found between hepatocellular carcinoma, chronic severe hepatitis B and chronic hepatitis B. With 50 samples detected, we found out 10 of them emerged G1896A mutation. In the 10 samples, 4 of them were genotype B, 6 of them were genotype B+C. There was significant difference in the mutation rate between the two genotypes(χ~2 =4.51 ,P<0.05).Conclusion: Genotype B is the most dominant type for HBV strains, followed by mixed genotype B and C infection. Genotype C decreased compared with the previous years. There is no relationship between the gender and HBV genotypes. No significant difference was found between HBV genotype and HBV DNA level. However, compared with genotype B, patients with mixed genotype B and C seem more likely to progress to liver cirrhosis(P<0.05).Mixed genotype B and C infection has a higher mutation rate than genotype B. GQ-PCR has a higher sensitivity and specificity for precise simultaneous genotyping and quantifing HBV clinical samples, and can replace the traditional genotyping assays.