Low level virus replication in infants with vertically transmitted fulminant hepatitis and their anti-HBe positive mothers.

Perinatal transmission of hepatitis B virus (HBV) occurs in about 10%-20% of anti-HBe seropositive mothers. The babies are at risk of developing fulminant hepatitis. In most cases no viral DNA has been detected in the sera of mothers and children by conventional hybridisation techniques. Thus, the aim of our investigation was to demonstrate HBV DNA in three children with liver failure and their anti-HBe positive mothers by more sensitive molecular hybridisation techniques. The babies were healthy at birth and did not receive vaccination. At 3 months of age they developed acute liver failure and died from liver insufficiency. Only in one child serum HBV DNA was detected by dot blot hybridisation, but polymerase chain reaction (PCR)-detectable HBV DNA was present in all sera. The liver specimen was negative for HBV DNA by Southern blot hybridisation, but showed a focal distribution of viral sequences as determined by in situ hybridisation. This finding was confirmed by PCR. Our results prove that chronic anti-HBe positive HBsAg carrier mothers and their babies show a low level virus replication. Fulminant hepatitis is due to vertical transmission of very small amounts of viral DNA, only detectable by most sensitive techniques like PCR and in situ hybridisation. Our findings underline the necessity to vaccinate all babies of HBsAg positive mothers regardless of HBeAg/anti-HBe status.