These events have clinical relevance as they associate with remission of liver-cell damage, indicating that virus replication is a pre-requisite for triggering hepato-cellular injury. liver function assessments and viral load during the first months of transplant, and to pay a special attention in slowly tapering the immunosuppression in these patients. Lamivudine reduces HBv viremia, but favors the emergence of HBv polymerase gene mutants and should be individually discussed. Both in case of HBv or HCv hepatitis reactivation with ALT 10N concomitantly to an increase in viral load at time of immune reconstitution, steroids should be given. In case Dihydrotanshinone I there is no alternative than a HBv or HCv positive geno-identical donor, the risk of viral hepatitis, including acute liver failure and late complications, should be balanced with the benefit of transplant in a given situation. Dihydrotanshinone I == Introduction: == The occurrence of contamination with Hepatitis B (HBV) or Hepatitis C virus (HCV) in patients undergoing allogeneic or autologous stem cell transplantation (HSCT) poses several clinical problems, as these infectious complications can jeopardize the ultimate prognosis, due to the possibility of progression to fulminant hepatic failure and also Dihydrotanshinone I to possible evolution to chronic active hepatitis and cirrhosis. Although the risk of acquiring HBV and HCV contamination from blood transfusion is usually nowadays greatly reduced, HSCT patients still represent a group at high risk, being prone to becoming infected due to the lack of immune competence given both the hematological disease and the conditioning regimen they receive before HSCT. Moreover, these patients may already be infected at transplant. Lastly, patients undergoing allogeneic HSCT may have a single related donor who is an HBV or HCV carrier, and this event is far from exceptional, especially in geographic areas where these viruses are endemic. The behavior of HBV and HCV contamination and related disease is usually often unpredictable in this cohort of patients both in the short-term and long-term outcome. == Hepatitis B Virus Contamination and Related Liver Disease == == Biology and Pathogenesis Dihydrotanshinone I of Hepatitis B virus: == HBV is usually a DNA virus classified in the EPADNA Virus Family. Its molecular organization and replication mechanisms have been extensively characterized1. The virus replicates in hepatocytes with high efficiency and viral replication produces a large amount of viral particles with high level of viraemia. HBV is Dihydrotanshinone I also able to integrate its genome into the host DNA and produces a number of structural and non-structural proteins which modulate the virus-cell interactions. Some of these proteins have regulatory and transcriptional functions which control gene expression and may be involved in hepato-carcinogenesis. The replicative phase of HBV contamination is characterized by the presence of a Rabbit polyclonal to IL4 soluble viral protein (HbeAg) and of HBV-DNA in serum. Seroconversion to anti-Hbe characterizes the transition from the replicative into the non-replicative phase (integration phase) and is usually associated with disappearance of viraemia. These events have clinical relevance as they associate with remission of liver-cell damage, indicating that virus replication is usually a pre-requisite for triggering hepato-cellular injury. Complete recovery from HBV contamination is associated with seroconversion from HbsAg positive to antiHBs positive status. In the past decade, accumulating evidence indicates that some patients may become chronically infected with HBV with persistent virus replication in the absence of HbeAg in serum. These cases are infected by HBV pre-core mutants that replicate persistently while not secreting HbeAg, due to point mutations in the coding region. HBV is not considered to be directly cytopathic in the immune-competent host and most evidence supports the conclusion that this host-immune response plays a major role in the pathogenesis of HBV-related liver damage. However, in the presence of exceptionally high virus replication and expression of virus products in the infected cells, a direct cytopathic mechanism may also supervene2,3. The current interpretation of HBV immune-pathology explains liver-cell damage as the result of reactivity of virus-specific cytotoxic T lymphocytes recognizing epitopes of the core or the envelope antigens on the surface of infected hepatocytes. The release of high concentration of soluble cytokines in the liver may also contribute to amplification of liver damage. The pathogenesis may be somehow different in patients infected by HbeAg unfavorable pre-core mutants, which are often associated with more severe flare-ups of liver damage. == Natural course of hepatitis B in the Immunocompetent Host: == HBV contamination is responsible for acute hepatitis, which may develop into a fulminant course in 1% of cases, or progress to chronic contamination in 510%. Chronic hepatitis B shows variable histological activity, that may eventually lead to cirrhosis in 2040% of patients. Further progression includes decompensated liver disease and death for liver-related causes. Carriers of HBV have a 300-fold increased risk of developing hepatocellular carcinoma (HCC). Most HBV carriers, however, have never.