Factors Affecting The HbeAg/eAb System

objective To analyze such factors' effect on HBeAg/eAb system as DNA load, genotypes,and mutations at precore(pC) and basal core promoter(Bcp) of hepatitis B virus.Method A cohort of 302 sera of patients with chronic hepatitis B were determined gene mutations at pC1896A,Bcp1762A/1764G and genotypes by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP),and detected HBsAg(s/n),HBeAg(s/co),and HBeAb(s/n) titer by Abbott Achitect quantity assay, and measured HBV DNA load by using fluorescent quantitative-PCR technology.Result HBV DNA(lg copies/ml) in HBeAg positive group[6.57(3.0-8.32)]was higher than that in HBeAg negative group[4.76(3.0-8.75)],P＜0.001.The incidence of pC1896A mutation in HBeAg positive group(33.3%) was lower than that in HBeAg negative group(62.3%);and the incidence of both pC and Bcp mutations in HBeAg positive group(9.0%) was lower than that in HBeAg negative group(29.9%) too,both P＜0.001.A regression equation contributing to HBeAg titer was obtained by using multi-factor linear regression analysis(stepwise),and two independent factors were screened HBV DNA load and pC1896A mutation.Factors affecting three status(HBeAg+/eAb-,HBeAg+/eAb+ and HBeAg-/eAb+ groups in order) of the HBeAg/eAb system were furtherly analyzed.Medians of age(year) were 31,33,and 41.5 in three groups in order,P＜0.001。Medians of HBV DNA(lgcopies/ml) were 6.62,5.6,and 4.73,and incidences of pC1896A were 31.4%, 45.5%,and 61.3%in three groups in order,both P＜0.001。According to this order, HBVDNA load reduced and pC 1896A mutation increased gradually and respectively。Finally,two equations contributing respectively to natural HBeAg loss and seroconversion were obtained by using binary probability logistic regression analysis (Forward:LR),and had alike characteristic.Conclusion Both pC1896A mutation and Bcp1762A/1764G co-mutation were related to the reduction of serum HBeAg expression.HBV DNA load was a positive factor on HBeAg titer,and pC1896A mutation was a negative factor.The older the age of HBV infection was and the more pC1896A mutation had,the larger probabilities of natural HBeAg loss and seroconversion would be.The more HBV DNA load,however,the smaller probabilities.