Genomic heterogeneity of hepatitis B virus (HBV) and outcome of perinatal HBV infection.

Background/Aims: Data regarding hepatitis B virus (HBV) genomic heterogeneity in perinatal infection are incomplete, although HBV variants might be involved in neonatal fulminant hepatitis (ALF). We investigated HBV variability in infected babies showing different clinical courses. Methods: We analyzed HBV genomes isolated from nine vertically infected babies and the mothers of four of them. Two infants born to HBe-antigen (HBeAg)-positive women developed a chronic infection; seven babies (six born to anti- HBe mothers) developed acute hepatitis that had a fulminant course in four cases and a benign course in three. Two babies developing ALF received anti-HBV immunoprophylaxis at birth. Results: Viruses carrying no significant mutation infected infants born to HBeAg-positive women. HBeAg-defective viruses were detected both in children with benign and fulminant hepatitis and their mothers. A double nucleotide mutation at positions 1762 and 1764 of the HBV core-promoter was found in two of the four infants with ALF, although it was not detected in isolates from the mother of one of them. No significant S gene mutation was found in HBV from any of the babies. Conclusions: This study indicates that HBV genomic heterogeneity is not primarily involved either in the evolution of the infection or the failure of neonatal HBV immunoprophylaxis.