This single-center prospective observational study aims at characterization of pathogenesis of ACLF. There will be three different cohorts investigated with the main endpoint mortality in these groups. 1. SAPIENT = Sepsis ACLF patients, to investigate the differences between ACLF and sepsis in cirrhosis 2. PROACT = Portal mediators as ACLF Targets, to assess portal venous biomarkers in patients receiving TIPS leading to ACLF and identify potential treatment targets 3. ELITE = prEdictors of beneficial LIver Tx in ACFL patiEnts, to assess in ACLF-patients receiving liver transplantation predictors of survival, which may improve selection of ACLF-patients for liver transplantation Secondary endpoints will be different in the three different cohorts and biological material will be collected for separate ancillary studies.