Introduction Hepatic macrophages (Kupffer cells) undergo inflammatory activation during the development of portal hypertension in experimental cirrhosis; this activation may play a pathogenic role or be an epiphenomenon. Our objective was to study serum soluble CD163 (sCD163), a sensitive marker of macrophage activation, before and after reduction of portal venous pressure gradient by insertion of a transjugular intrahepatic portosystemic shunt (TIPS) in patients with cirrhosis. Methods sCD163 was measured in 11 controls and 36 patients before and 1, 4 and 26 weeks after TIPS. We used lipopolysaccharide binding protein (LBP) levels as a marker of endotoxinaemia. Liver function and clinical status of the patients were assessed by galactose elimination capacity and Model for End Stage Liver Disease score. Results The sCD163 concentration was more than threefold higher in the patients than in the controls (median 5.22 mg/l vs 1.45 mg/l, p2=0.24, pConclusion Kupffer cells were activated in patients with liver cirrhosis in parallel with their portal hypertension. The activation was not alleviated by the mechanical reduction of portal hypertension and the decreasing signs of endotoxinaemia. The findings suggest that Kupffer cell activation is a constitutive event that may play a pathogenic role for portal hypertension.