[Relationship between hepatitis B surface antigen, HBV DNA quantity and liver fibrosis severity]

To explore the correlation between serum hepatitis B surface antigen (HBsAg) level and hepatic tissue pathological staging in patients with chronic hepatitis B (CHB).

Clinical data was collected from our hospital's records for 302 CHB patients with HBsAg-positive status for more than 6 months and who had undergone hepatic biopsy. The HBsAg level,HBV DNA level and other clinical data were measured using commercial diagnostic assays. Liver histology was scored using the GS staging system. Correlation between serum HBsAg quantity, HBV DNA quantity, stage of inflammation and degree of fibrosis was assessed statistically.

The correlation of serum HBsAg level and HBV DNA level was notable. The serum HBsAg level was a variable affecting hepatic tissue pathological stage significantly. Serum HBsAg level appeared to be a highly specific and sensitive diagnostic marker of hepatic fibrosis. As the severity of liver fibrosis increased, the quantitative levels of platelet (PLT), HBsAg and HBV DNA gradually decreased, and the APRI index gradually increased; there were significant differences between the groups (all P<0.001). Serum HBsAg and HBV DNA levels in patients with hepatitis B e antigen-positive (HBeAg(+)) status showed strong correlation (r=0.721, P<0.0001) by Spearman analysis. HBeAg(+) patients with moderate to severe fibrosis (S2-4) exhibited significantly lower serum HBsAg and HBV DNA levels compared with patients with no or mild fibrosis (S0-1; t=5.475 and 4.826, P<0.001). ROC analysis suggested that a serum HBsAg cutoff of 4.46 log 10 IU/mL (28 800 IU/mL) would provide a theoretical sensitivity of 76.3%, with theoretical specificity of 70.5% in HBeAg(+) CHB patients. A serum HBV DNA cutoff of 7.13 log 10 IU/mL (1.35*10(7) copies/mL) would provide a theoretical sensitivity of 71.1%, with theoretical specificity of 73.4% in HBeAg(+) CHB patients. Logistic regression analysis showed that the level of HBsAg was an independent prognostic factor of moderate to severe liver fibrosis, with alanine aminotransferase, aspartate aminotransferase, HBsAg, HBV DNA and PLT (P<0.001).

HBsAg and HBV DNA levels decrease gradually along with aggravation of liver fibrosis. The cutoff values of 28800 IU/mL for HBsAg and 1.35*10(7) copies/mL ofHBV DNA provide higher specificity and sensitivity for predicting the degree of liver fibrosis in HBeAg-positive CHB patients, and the former is an independent predictor of severe liver fibrosis.