[Advances in the diagnosis and treatment of the infection by the hepatitis B virus].

Infection by the hepatitis B virus (HBV) is a significant cause of morbidity and mortality, mainly due to evolvement to cirrhosis and hepatocellular carcinoma. The prevalence and genotypic distribution of HBV infection has marked geographic differences. HBV infection is a very dynamic process, with a phase of immune tolerance and high viral replication, followed by HBeAg clearance, not always accompanied by complete suppression of HBV replication. The latter situation corresponds to negative HBeAg hepatitis, which represents a group relatively resistant to therapy. The three approved drugs for the treatment of HBV infection (interferon alpha, lamivudine and adefovir) have limited efficacy. Relapses are more common with lamivudine and adefovir, requiring often long-term treatment. While the selection of lamivudine resistance mutations is frequent, adefovir has a high genetic barrier. HIV infection negatively impacts on HBV disease, requiring these coinfected patients strategies aimed to manage both viruses.