Acute-on-chronic liver failure (ACLF) is an ailment with high incidence of multiorgan failure (MOF) and consequent mortality. Systemic inflammation and susceptibility to infection are characteristic pathophysiological features. Prostaglandin E2 (PGE2) could subdue systemic inflammation and alleviate liver injury in mice model. However, there are no studies evaluating PGE2 as a predictor of early mortality.This study is designed to investigate whether plasma PGE2 and its receptors are associated with development of MOF and predict short-term mortality in patients with acute-on-chronic liver failure. By the way, we will also measure several other potential predictive factors (C-reactive protein,severe hyponatremia, Second infections,Diabetes mellitus,High density lipoprotein,interleukin-10,serum bile acids,ferritin,the neutrophil to lymphocyte ratio,soluable urokinase plasminogen activator receptor,vWF-Ag levels and FVIII-to-PC ratios).

Inclusion Criteria:

• Clinical diagnosis of acute-on-chronic liver failure according to Asian-Pacific Association for the Study of the Liver (APASL) diagnostic criteria

Exclusion Criteria:

• Hepatocellular carcinoma(HCC)
• Portal vein thrombosis
• Pregnancy
• Human immunodeficiency virus (HIV)
• Patients who had received immunomodulator,or cytotoxic/immunosuppressive therapy within at least the preceding 12 months

The cohorts will be selected from Provincial General Hospital