Objective: Despite intermittent flares, progression of chronic infection with hepatitis B virus has generally been related to a decrease in replication levels. In our laboratory, this decrease has been found to be associated with a decline in circulating full-length transcripts (fRNA) and to a shift to truncated transcripts (trRNA). Monitoring fRNA and trRNA as markers allows a more detailed analysis of high or low or non-replicative HBV infection stages.
Methods: Here, we determined circulating HBV RNA in newborns from a total of 69 HBsAg-positive carrier mothers with and without immunotherapy administered during the last 3 months of pregnancy.
Results: In line with previous observations, serum HBV DNA in newborns was only found when their mothers had not been treated (7/23). HBV RNA measured as trRNA was detected both in the presence and in apparent absence of serum HBV DNA. fRNA (coexisting with HBV DNA and HBeAg) was detected only in newborns from untreated mothers (8/23) and was always combined with trRNA. In contrast, trRNA was found in newborns from both untreated (20/23) and treated mothers (26/46).
Conclusions: Our data strongly suggest a direct intrauterine transmission of a low-replicative (unapparent) HBV infection stage. However, a feto-maternal transfer of trRNA (transfer of a marker) rather than transmission of the infectious virus cannot be excluded.
(c) 2007 S. Karger AG, Basel.