An estimated 15 to 40 per cent develop complications of hepatitis B virus (HBV) infection, including cirrhosis, decompensation, and hepatocellular carcinoma (HCC). HBV infection has a mortality rate of 2.7 to 3.5 per 100000 every year. The introduction of new antiviral therapies has dramatically changed the clinical scenario due to the improvement either in the pre-transplant setting or post-transplantation.
Liver transplantation is a life-saving treatment for patients with an end-stage liver disease. Viral hepatitis B is one of the most common causes of cirrhosis and hepatocellular carcinoma and hence an extremely frequent indication for liver transplantation. In patients with HBV-related cirrhosis, the 5-year incidence of hepatic decompensation (liver failure) is around 20 per cent. Transplantation stands as the only option.
The indications for liver transplantation for Hepatitis B-related complications fall into three major categories. Firstly, transplantation is indicated for those with cirrhosis and evidence of decompensation which include hepatic encephalopathy, kidney dysfunction, fluid accumulation, gastrointestinal bleed, and refractory ascites, amongst others.
The second category includes those with severe hepatitis flares with evidence of acute liver failure, where the transplant needs to be done on urgently. Finally, those with HBV-related liver cancer within transplantable criteria, and where resection is not feasible.
In those patients for whom liver transplantation becomes necessary, Hepatitis B viral suppression ideally to undetectable levelsusing newer antiviral drugs remains important in preventing HBV recurrence in the new liver graft. Studies have shown a direct correlation between viral load at time of transplant and rate of Hepatitis B recurrence after transplantation.
While awaiting a liver transplantation, patients should be monitored carefully at least every 3 months for viral titres and response to medications, apart from scanning them for previously undetected and newly developing liver tumours.
Despite the removal of the liver, HBV may still persist in extrahepatic sites such as the lymph nodes, spleen, peripheral blood mononuclear cells, and other organs. HBV may also persist in the circulation at the time of transplantation. These sites serve as reservoirs for re-infection of the new graft. Furthermore, reactivation of latent HBV occurs with the use of immunosuppressive therapy after transplantation.
The introduction of newer therapies has reduced the recurrence of HBV infection after liver transplantation, which was considered a major problem in the past;it is no longer a significant cause of death/graft loss.
A shifting paradigm of using medicines with high barrier to resistance has showing excellent clinical outcomes. In the future, other novel methods targeting different sites of viral replication cycle together with restoration of the host immune response may allow complete eradication or long-term immune control of HBV.