Liver cirrhosis is the end stage of chronic liver diseases. A major complication is the occurrence of ascites, which, along with other complications, defines decompensated cirrhosis and is linked to high mortality. The main cause of acute decompensation, subsequently leading to liver failure and death, is infection, including spontaneous bacterial peritonitis (SBP), an infection of the ascitic fluid. An impaired immune response plays a key role in this process. This project will test the hypothesis that mucosa-associated invariant T (MAIT) cells in the peritoneal cavity of patients with decompensated cirrhosis could serve as a potential therapeutic target for SBP treatment.