Detection And Analysis Of Serum HBV DNA Gene Fragments In HBsAg-Negative Patients

Objectives:To investigate the prevalence of occult Hepatitis B virus infection among HBsAg-negative patients and analyze its clinic characteristics.Methods:1) Serum samples were collected from 110 HBsAg negative patients in the First Affiliated Hospital of Chongqing Medical University from March 2012 to January 2014 whose quantitative of HBV DNA were undetectable by fluorescent quantitative PCR.2) HBV DNA was extracted with high pure viral nucleic acid kit. The S, X and C gene of HBV genome were amplified by nested PCR.3) The rates of OBI-positive were compared by statistical methods, between patients in different gender、age and serological pattern, as well as in patients with different causes of liver damage.Results:1) The patient could be defined as OBI as at least two regions were amplified positive.26 cases with OBI-positive were identified in 110 cases without HBsAg.2) The prevalence of OBI among male and female were 28.8% and 15.9%. The OBI positive rates were 20.8%,21.7%,30.8% in group of age not more than forty, between forty-one and sixty, no less than sixty-one respectively. The prevalence of OBI among groups of single anti-HBc(+) and anti-HBs(+)/anti-HBc(±) were 23.0% and 24.4%. The rate of OBI-positive had no statistically significant differences with gender, age, serological markers.3) The incidence of OBI in patients who were liver injury was 35.1%, while 11.3% in normal liver function, which had significant statistical difference. 4) The prevalence of OBI among liver injury of undetermined origin and defined origin was 31.0%% 39.3% respectively.Conclusions:1) OBI is more likely to occur in HBsAg-negative individuals with liver dysfunction.2) OBI is one of the causes of unexplained liver damage. Therefore, prompt detection of trace HBV DNA is necessary to exclude OBI in those individuals.3) OBI may cooperate with other factors leading to hepatitis.