CD274 and synovial sarcoma: When hepatitis B virus (HBV)-associated cirrhosis is complicated with severe sepsis (SS), HBV-related acute-on-chronic liver failure (HBV-ACLF) can be caused by the superposition of monocyte PD-L1 up-regulation, and monocyte PD-L1 expression can also predict the 28-day mortality of HBV-ACLF (142).