Occult HBV infection is characterized by the absence of serum HBsAg with persistence of low level of intrahepatic HBV DNA. Several suggested mechanisms for the origin of occult HBV infection include strong suppression of viral replication and gene expression, mutation in the regulatory regions of HBV genome, formation of immunoglobulin-bound HBsAg, viral interference, and blockage of HBsAg secretion from infected hepatocytes. Standardized assays are not yet available, and sensitive HBV DNA amplification assay is necessary for the diagnosis of cryptic infection. Detection rate of HBV DNA is highest in IgG anti-HBc positive population. However, neither anti-HBc nor anti-HBs can be detected in a significant proportion of infected persons. Occult HBV infection occurs in a number of clinical settings and is highly prevalent in HCV-infected patients as well as in patients with cryptogenic chronic liver disease including hepatocellular carcinoma.
DNA, Viral/analysis ; Hepatitis B/*diagnosis/*epidemiology/metabolism ; Hepatitis B Antibodies/blood ; Hepatitis B Core Antigens/immunology ; Hepatitis B Surface Antigens/blood ; Humans

<b>OBJECTIVEb>The present aimed to observe the effect of phosphatase inhibitor cyclosporine A on the subcellular location and on expression of HBcAg in HepG2.2.15 cells.

<b>METHODSb>Thirty micrograms/ml of cyclosporine A (CSA) was added into HepG2.2.15 cell culture system and on days 2 and 4 HBcAg and HBsAg were respectively stained with fluorescent immunocytochemistry and observed under confocal microscope. Cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling method.

<b>RESULTSb>HBcAg was mostly expressed in cytoplasm in the control HepG2.2.15 cells. After 2 days CSA administration of the expression of HBcAg and HBsAg in cytoplasm significantly decreased and the signals of HBcAg in nucleus increased , whereas the HBcAg was still mainly expressed in nucleus in about 1/4 of the cells. Cell apoptosis was observed in about 30% of the cells.

<b>CONCLUSIONb>CSA improves the nuclear entry of core protein. The increase of HBcAg in nucleus was likely to be related with it's phosphorylation and cell aging or apoptosis.

Active Transport, Cell Nucleus ; Apoptosis ; Cell Line, Tumor ; Cell Nucleus ; metabolism ; Cyclosporine ; pharmacology ; Cytoplasm ; metabolism ; Hepatitis B Core Antigens ; analysis ; metabolism ; Hepatitis B Surface Antigens ; analysis ; Humans ; In Situ Nick-End Labeling ; Phosphorylation

BACKGROUNDS/AIMS: Negative hepatitis B core antigen (HBcAg) staining in hepatocytes is indicative of viral replication by an active immune response. HBcAg is expressed mainly in the cytoplasm in patients with active hepatitis and hepatocyte regeneration, and mainly in the nuclei of hepatocytes in patients with minimal liver injury in the absence of hepatocyte regeneration. The aim of this study was to elucidate whether the existence and expression pattern of HBcAg predicts the response to antiviral treatment. METHODS: The study involved 58 patients with biopsy-proven chronic hepatitis B who were treated with lamivudine. Hepatitis B e antigen (HBeAg), antibody to HBeAg, hepatitis B virus DNA, and alanine aminotransferase in serum were recorded every 3 months. The inflammation grade and the fibrosis stage of chronic hepatitis were scored from 0 to 4 according to lobular inflammation, portal inflammation, periportal inflammation, and fibrosis. RESULTS: The 58 patients included 49(84%) HBcAg-positive patients, with HBcAg staining confined to the cytoplasm in 15(31%) and in both cytoplasm and nuclei in 34(69%). The grade of lobular inflammation and the total histology score were significantly higher in patients with cytoplasmic expression of HBcAg than in HBcAg-negative patients (lobular inflammation: 2.9 vs 2.1, P=0.02; total histology score: 12.2 vs 10.3, P=0.04). The virologic responses at 3, 6, 9, and 12 months differed significantly between the cytoplasmic and mixed expression groups (P<0.01). CONCLUSIONS: The expression pattern of HBcAg (including its possible absence) before initial therapy appears to predict the response to antiviral treatment.
Adult ; Antiviral Agents/*therapeutic use ; DNA, Viral/blood ; Female ; Hepatitis B Core Antigens/*analysis/metabolism ; Hepatitis B e Antigens/metabolism ; Hepatitis B virus/isolation & purification ; Hepatitis B, Chronic/*drug therapy/virology ; Humans ; Lamivudine/*therapeutic use ; Male ; Middle Aged ; Predictive Value of Tests ; Retrospective Studies