HBeAg阳性慢性HBV感染孕妇血清HBV DNA水平与HBsAg滴度的相关性及HBV PreS/S区基因变异对二者相关性的影响

Objective To analyze the correlation between serum HBV DNA level and HBsAg titer in hepatitis B e antigen positive pregnant women without antiviral therapy, and investigate the impact of genomic variability of preS/S regions on their correlations. Methods Prenatal serum samples from 882 pregnant women with chronic HBV infection who were positive for HBsAg, HBeAg and HBV DNA and were not on antiviral therapy were included in the analysis. The Abbott i2000 and m2000 systems were used to qualitatively or quantitatively detect HBsAg, HBeAg and HBV DNA levels, respectively. HBV genotyping was performed using a type-specific primer nested polymerase chain reaction (nPCR). In addition, serum samples of pregnant women with HBV DNA levels correlated with HBsAg titer and HBV DNA levels higher than HBsAg titers were used to perform preS/S region amplification by nPCR method. PCR products were directly sequenced and mutation sites were analyzed by MEGA6.0 stasticial software. Mann-Whitney U test was used for the measurement data, and 2-test test for count data. Correlations between variables were analyzed using Spearman’s rank correlation. Results Serum HBsAg titer of HBeAg-positive pregnant women was positively correlated with HBV DNA level (r = 0.754, P < 0.01). Compared with the control group, mutation sites A60V (100% vs. 15.38%, χ2 = 7.61, P < 0.01), V90A (100% vs. 30.77%, χ2 = 4.43, P < 0.05) and I161T of HBV preS/S region (80.00% vs. 0, χ2 = 9.14, P < 0.01) showed a significant decrease in HBsAg titer. Conclusion Serum HBV DNA levels were positively correlated with HBsAg titer in HBeAg-positive pregnant women. Therefore, serum HBsAg titer may be used as a surrogate marker of serum HBV DNA. Single or multiple amino acid mutations sites A60V, V90A, and I161T in preS/S region may be one of the reasons that lead to a significant drop in HBsAg titer and affect its correlation with HBV DNA levels. Key words: Hepatitis B virus; Hepatitis B virus e antigen; Hepatitis B surface antigen; Variation