Chronic hepatitis B with flare due to co-infection of hepatitis delta virus during lamivudine therapy.

In 1997, a 27-year-old homosexual man contracted acute hepatitis B that developed into chronic hepatitis. Because of repeated flares, administration of lamivudine was started in March 2002. Hepatitis B virus (HBV) DNA immediately decreased, but the serum level of alanine aminotransferase gradually increased. Drug-induced hepatitis due to lamivudine was excluded. It was suspected that the progression of liver damage was caused by hepatitis delta virus (HDV), because the patient was positive for both anti-HDV antibody and HDV RNA. Co-infection of HDV should be considered a possibility if liver injury is not improved by lamivudine therapy.