The diminished postoperative capacity of blood leukocytes to produce IL-6 is associated with high concentrations of IL-6 in the circulation

Surgical trauma is followed both by a transient increase of interleukin 6 ( IL-6) concentrations In the serum and impaired function of circulating leuk ocytes. Perioperatively, we investigated the relationship of IL-6 concentra tions in the serum with lipopolysaccharide (LPS)-stimulated cytokine produc tion in the whole blood of patients undergoing elective major abdominal ope rations. In 50 patients, we found a transient increase of IL-6 concentratio ns in the serum. Six hours after skin incision, in vitro stimulated product ion of IL-6 and TNF alpha was diminished by 72% (P<0.05), A significant inc rease in cytokine production was observed three days postoperatively, howev er this was 63% below the preoperative values. Patients with high concentra tions of circulating IL-6 showed a significantly lower stimulated IL-6 prod uction than patients with low serum concentrations of IL-6, We conclude, th at two opposing effects are associated with surgery: an activation leading to IL-6-release into the circulation, and a prolonged hyporesponsiveness of circulating leukocytes. These reactions are positively related. (C) 2000 A cademic Press.