Intrahepatic expression of hepatitis B core and surface antigens in chronic hepatitis delta-virus infection

To evaluate the interference of hepatitis B virus (HBV) protein expression in the liver in chronic hepatitis delta-virus (HDV) infection, the intrahepatic expression of hepatitis B core and surface antigens (HBcAg and HBsAg) was studied in 36 HBsAg carriers who were seropositive for anti-HDV and in 36 anti-HDV negative controls [18 with serum hepatitis B e-antigen (HBeAg) and 18 with anti-HBe]. Of 18 HBeAg-positive patients with anti-HDV, 12 had HDV antigen (HDAg) in the liver. HBcAg was positive in 66.7% (8/12) of the HBeAg-positive patients with HDAg in the liver, and in 94.4% (17/18) of controls (p=0.14). The distribution of HBcAg was exclusively cytoplasmic in 75% (6/8) of HDV-infected patients, but was mixed nuclear and cytoplasmic in 70.6% (12/17) of the controls. The prevalence and quantitative expression of HBcAg in the nucleus, but not in the cytoplasm, were significantly decreased in chronic HDV infection. HBsAg was positive in 91.6% (11/12) of HBeAg-positive patients with HDV infection and in all controls. Membranous expression of HBsAg was detected less frequently in HDV-infected patients than in controls (7/12 vs. 17/18, p=0.05), while the prevalence and quantitative expression of HBsAg in the cytoplasm showed little or no difference. HDAg was detected in all of the anti-HBe-positive patients with anti-HDV. Of these, none had HBcAg detectable in the liver, nor did controls, while HBsAg was detected exclusively in the cytoplasm in 94.4% (17/18). The prevalence and quantitative expression of HBsAg in the cytoplasm was not different for HDV-infected patients or controls. The results demonstrate: (1) decreased expression of nuclear HBcAg and membranous HBsAg in HBsAg carriers with chronic HDV infection, suggesting decreased levels of HBV replication and (2) that HDV has little or no effect on the cytoplasmic expression of HBsAg. The mechanisms regulating the expression of HBcAg and HBsAg in the liver in chronic HDV infection await further investigation.