SELECTIVE CYTOKINE RELEASE INDUCED BY SERUM AND SEPARATED PLASMA FROMSEPTIC PATIENTS

Objective: To investigate the activating properties of serum from sept ic patients on monocytes and the potential effect of plasmapheresis. D esign: Prospective controlled study. Setting: Teaching hospital, Germa ny. Subjects: 7 Patients with life-threatening systemic inflammatory r esponse syndrome (SIRS) and 4 control patients with serious but not li fe-threatening conditions. Interventions: We measured the amount of me diators released by healthy donor monocytes incubated in serum and sep arated plasma from septic patients. Main outcome measures: Release of interleukin 6 (IL-6), prostaglandin E(2) (PGE(2)), interleukin 1 (IL-1 ), and tumour necrosis factor (TNF). Results: The serum and separated plasma from infected patients selectively induced the release of IL-6 and PGE(2). The mean PGE(2) production in serum was 10895 pg/ml/10(5) cells, and in plasma was 14023 pg/ml/10(5) cells compared with a contr ol of 0 (p < 0.05). The mean IL-6 production in serum was 4925 pg/ml/1 0(5) cells and in plasma 4262 pg/ml/10(5) cells compared with a contro l of 0 (p < 0.05). In contrast, IL-1 and TNF did not seem to be associ ated with sepsis and were present in small amounts if at all. Addition al stimulation with lipopolysaccharide (LPS) increased the serum and p lasma induced release of PGE(2) and IL-6 (p < 0.05). Serum and plasma from septic patients did, however, selectively reduce the maximum LPS- stimulated release of PGE(2) and TNF (p < 0.05) compared with healthy donor monocytes. Conclusion: Serum and separated plasma from septic pa tients contained agents which induced monocytes to release mediators w ithout additional stimulation, and modified their response to LPS. Rem oving plasma from septic patients may therefore reduce the deleterious effect of the inflammatory response.