Abstract: Objective The aim of this study was to investigate the distribution of pathogens and serum Th1/Th2 cytokine changes in patients with hepatitis B virus related acute-on-chronic liver failure (HBV-ACLF) and nosocomial infections (NI). Methods 63 patients with HBV-ACLF were admitted to our hospital between December 2019 and December 2021, and out of them, 35 patients were found having NI. Serum Th1 cytokines, such as interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), and Th2 cytokines, including IL-4, IL -6 and IL-10 levels were detected by ELISA. Serum C-reactive protein (CRP) and procalcitonin (PCT) levels were detected by immunofluorescence, and serum lipopolysaccharide (LPS) level was detected by limulus test. The isolation and identification of pathogens were conducted by microbiological analyzer. Results In the 35 HBV-ACLF patients with NI, 72 strains of pathogens, including 44 strains of Gram-negative and 28 strains of Gram-positive bacteria were found; serum CRP, PCT and LPS levels in patients with NI were (78.7±12.9)mg/L,(6.2±0.2)ng/mL and (0.9±0.1)EU/ml, significantly higher than [(15.9±1.7)mg/L, (0.9±0.1)ng/mL and (0.2±0.1)EU/ml, respectively, P<0.05] in patients without NI; serum TNF-α, IFN-γ and IL-6 levels in patients with NI were (16.5±1.7)pg/mL, (27.8±2.3)pg/mL and (12.5±1.3)pg/mL, all significantly higher than [(11.7±1.2)pg/mL, (20.2±2.1)pg/mL and (4.2±0.4)pg/mL, respectively, P<0.05], while serum IL-2, IL-4 and IL-10 levels were (3.3±0.3)pg/mL, (11.8±1.1)pg/mL and (10.2±1.0)pg/mL, respectively, P<0.05] in patients without NI; the 28 d and 90 d survivals in patients with NI were 28.6% and 20.0%, both significantly lower than 71.4%(x²=8.239, P=0.022) and 57.1%(x²=7.014, P=0.025) in patients without NI. Conclusion The mortality of HBV-ACLF patients with NI is high, and the main pathogens of bacterial infection is Gram-negative bacteria, which might have the Th1/Th2 cytokine imbalance.

Key words: Acute-on-chronic liver failure, Nosocomial infection, Pathogens, Th1/Th2 cytokines