Background: The detection of bacterial DNA in serum and ascitic fluid from patients with cirrhosis and ascites is interpreted as molecular evidence of intestinal bacterial translocation and considered sufficient to activate the cellular immune response. In vitro studies on ascitic fluid culture have shown a close relationship between the synthesis of several cytokines and nitric oxide and the presence of bacterial DNA. Since different cell types give rise to cytokines, flow cytometry becomes a powerful tool to discriminate between populations involved in a bacterial challenge.
Objective: To study the pre-activation status of macrophage/monocyte population ex vivo according to the presence of bacterial DNA.
Patients: Patients with cirrhosis and culture-negative, non-neutrocytic ascites, with or without the presence of bacterial DNA in blood and ascitic fluid were studied.
Methods: Flow cytometry analysis of intracellular cytokine expression in monocyte/macrophages from ascitic fluid was performed in basal conditions and after 12 h of cell stimulation adding lypopolysaccharide.
Results: Monocyte/macrophages from patients with bacterial DNA showed a significantly higher production of interleukin-6 and tumor necrosis factor alpha in basal conditions than that in cells from patients without the presence of bacterial DNA. The addition of lipopolysaccharide produced a non-significant increment in the expression of these cytokines in patients with the presence of bacterial DNA, while this increment became significant in the other group of patients.
Conclusions: Bacterial translocation in patients with cirrhosis and ascites increases the basal intracellular cytokine expression, reducing its functional reserve capability.