Epidemiological investigation of hepatitis B virus infection and analysis of virus mutations in hepatitis B surface antigen positive students and their first-degree relatives / 第二军医大学学报

ABSTRACT

Objective To explore the infection status of hepatitis B virus (HBV) in families of hepatitis B surface antigen (HbsAg) positive students and the mutations of HBV related to hepatocellular carcinoma, so as to provide theoretic evidence for the prevention and control of HBV infection and hepatocellular carcinoma. Methods A total of 1 611 students were investigated; they were from 60 classes of 15 schools and kindergartens in Pudong New Area, Shanghai, China, and 8 HBsAg positive students were found. These 8 students and their 18 first-degree relatives were enrolled in this study. Venous blood samples were collected to test the 5 markers of hepatitis B using enzyme linked immunosorbent assay. HBV DNA was detected by fluorescent PCR. HBV genome, basic core promoter (BCP) region and PreS region were detected using multiplex-PCR and nested PCR combined with cloning and sequencing. Results The positive rates of HBsAg and HBcAb in the first-degree relatives were 33.3% (6/18) and 38.9% (7/18), respectively. Both HBsAg and HBcAb positive rates in the mothers were 71.4% (5/7), which were significantly higher than those of the other first-degree relatives (P0.05). Seven of 8 families (87.5%) had 2 or more members infected or had ever infected with HBV. Fourteen of 26 members in 8 families had positive HBsAg, with a positive rate of 53.8%. A total of 4 groups of mothers and children received gene detection. Three groups of them had type C HBV gene, and 1 group had type C in mother and type B in child. Among the hepatocellular carcinoma-related HBV mutations, the mutation frequency of hot spots in BCP region was lower in the children than that in the mothers. Eight HBV mutation sites of type C in PreS region were found in both the mothers and children, and none of the remaining key sites were found in the children. Conclusion There is obvious family clustering of HBV infection, suggesting that HBV infection of students is more likely to be transmitted through mother-to-child transmission, but there are other ways of infection, such as acquired blood. The evolution degree of HBV gene in children is lower than that in mothers, which conforms to the rule of HBV evolution.