Immunomodulatory receptor VSIG4 is released during spontaneous bacterial peritonitis and predicts short-term mortality

•VSIG4 expression is high on human resting, large peritoneal macrophages (PMs) that co-express CD206, CD163, and MERTK.•PM activation by TLR agonists or infection results in the loss of surface VSIG4 and release of soluble VSIG4 (sVSIG4).•Ascites sVSIG4 correlates with organ dysfunction and inflammation during SBP.•Higher ascitic fluid sVSIG4 concentrations indicated increased risk of 90-day mortality in 120 patients with SBP.•Addition of an antibody binding to the extracellular domain of VSIG4 enhanced phagocytosis of bacteria in vitro.