Perinatal hepatitis B virus infection caused by antihepatitis Be positive maternal mononuclear cells.

To investigate the infectivity of hepatitis B virus (HBV) from mothers to their newborn offspring, HBV-DNA in plasma and peripheral mononuclear cells from 28 antihepatitis Be positive, hepatitis B surface antigen positive carrier mothers was examined by a highly sensitive polymerase chain reaction/Southern hybridisation technique. HBV specific DNA was detected in three maternal mononuclear cell samples, but was absent in plasma. Two of four infants born to the three mothers with HBV-DNA positive mononuclear cells developed acute or fulminant hepatitis within three months after birth. Two infants were effectively prevented from infection with HBV by combined hepatitis B immunoglobulin/HBV vaccine administration. The 25 infants born to the HBV-DNA negative mothers were free of HBV infection within the next seven months to 3.5 years. These results suggest that latent infection with HBV in maternal mononuclear cells is responsible for perinatal HBV infection.