Abstract: Objective To investigate hepatitis B virus （HBV） subgenotypes distribution and its implication in patients with chronic hepatitis B in Guangzhou. Methods 424 patients were enrolled in this study,including 137 with chronic hepatitis B（CHB）,90 with HBV-related acute-on-chronic liver failure （HB-ACLF）,90 with 1iver cirrhosis（LC） and 107 with hepatocellular carcinoma（HCC）. HBV subgenotypes were determined by direct sequencing of HBV S gene and the phylogenetic tree was constructed. The data was compared by x² test,one way ANOVA and Logistic regression analysis. Results Out of 424 patients with HBV infection, 269（63.44%） were infected with HBV B2,117 （27.59% with HBV C1,36 （8.49%） with HBV C2 and 2 （0.47%） with C5; the HBV B2,C1,C2 and C5 Infection in patients with CHB were 70.1%,24.09%,5.11%,0.73%;the HBV B2,C1 and C2 in patients with HB-ACLF were 87.78%,7.78%,4.44%,with HBV B2 subgenotpe significantly higher than in patients with CHB（x²=9.641,P=0.002）,with LC（x²=19.565,P=0.000） or with HCC（x²=26.789,P=0.000）;the subgenotypes of HBV B2,C1 and C2 in patients with LC were 50.00%,36.67%,13.33%,with HBV C1 and C2 subgenotpes significantly higher than in patients with CHB（x²=6.262,P=0.012,x²=4.790,P=0.029） or in patients with HB-ACLF（x²=25.894 P=0.000,x²=4.390,P=0.036）;the subgenotypes of HBV B2,C1,C2 and C5 in HCC patients were 45.79%,41.12%,12.15%,0.93,with HBV C1 and C2 subgenotypes significantly higher than in patients with CHB（x²=11.264,P=0.001,x²=3.957,P=0.047） or in patients with HB-ACLF（x²=28.327,P=0.000,x²=3.904,P=0.048）;there was no significant difference between HCC patients with HBV C1 and C2 subgenotype infection and LC patients;Logistic regression analysis showed that HBV B2 subgenotype was the independent risk factor for HB-ACLF occurrence, and HBV C genotype was the independent risk factor for HCC occurrence. Conclusion HBV B2,C1,C2 are the most frequent HBV subgenotypes in Guangzhou. The HBV B2 subgenotpe is prevalent in patients with HB-ACLF and HBV C1 and C2 is frequent in patients with LC and HCC.

Key words: Hepatitis B, HBV Subgenotypes, Sequence analysis, Phylogenetic tree