Peritoneal macrophages from patients with cirrhotic ascites show impaired phagocytosis and vigorous respiratory burst

Cirrhotic patients (CPs) are susceptible to spontaneous bacterial peritonitis (SBP). Aim of this study was to examine if this susceptibility was related to peritoneal macrophages' (PMs) altered host defence. Absorbance of phagocytosed particles by PMs from CPs was lower than that of control (31.88% vs. 77.2%). Particle opsonisation increased the absorbance to 41% in CPs' PMs, and this value remains lower than the control; 77.2%. Respiratory burst (RB) was expressed as fluorescence index values, and these were higher in PMs from CPs than in controls (82 vs. 41, 73 vs. 26 and 71 vs. 26). IFN-γ made no further increase of RB values in PMs from CPs. CD14 expression was also higher in CPs' PMs. IFN-γ significantly downregulated CD14 expression in both CPs' PMs and control. Reduced phagocytosis by predominantly CD14-positive PMs from CPs could be related to intense RB. Findings suggest altered host defence that could contribute to susceptibility to SBP.