Liver failure (LF) is a dramatic clinical syndrome with massive necrosis of liver cells. Although liver transplantation provides an option to cure patients suffering with LF, lack of donors, postoperative complications, especially rejection, and high cost limit its application. Previous study showed that bone marrow derived mesenchymal stem cells (BM-MSCs) the novel and promising therapeutic strategy, BM-MSCs can replace hepatocytes in injured liver, and effectively rescue experimental liver failure and contribute to liver regeneration. Plasma exchange (PE) can improve internal environment by removing endotoxin, it helps the liver regeneration and functional recovery and make UC-MSC differentiation into hepatocyte like cells, and exert immunomodulatory function. In this study, safety and efficacy of human umbilical cord mesenchymal stem cells (UC-MSCs) transplantation combined with plasma exchange (PE) for patients with liver failure caused by hepatitis B Virus will be evaluated.

To investigate safety and efficacy of human umbilical cord mesenchymal stem cells (UC-MSCs) transplantation combined with plasma exchange (PE) for patients with liver failure caused by hepatitis B virus.

Inclusion Criteria:

• Written informed consent
• Acute-on-Chronic liver failure caused by hepatitis B virus
• Model for End-Stage Liver Disease (MELD) <30

Exclusion Criteria:

• Liver failure caused by other reasons, such as autoimmune diseases, alcohol, drug and so on
• History of severe hepatic encephalopathy or variceal bleeding during the last two months before enrollment
• Severe problems in other vital organs(e.g. the heart, renal or lungs)
• Severe bacteria infection
• Tumor on ultrasonography, CT or MRI examination
• Pregnant or lactating women