Plasma exchange, but not extracorporal recirculation nor removal of white blood cells, depresses plasma levels of IL-1 during severe gram-negative septicemia

Abstract

The production and secretion of interleukin-1 (IL-1) is a persistent and important event during early gramnegative septicemia. To investigate whether interventions such as plasma exchange, leukapheresis and extracorporal recirculation of autologous blood affected the plasma IL-1 activity, an experimental porcine model of septicemia was employed. 42 anesthetized piglets were divided into three sets each of 14 animals, and observed for 10 h after a sublethal i.v. infusion of live E.coli bacteria. Two animals were studied simultaneously in each set. Starting 135 min after the bacterial infusion, one animal in each pair was submitted to either plasma exchange, extracorporal recirculation or removal of white blood cells (leukapheresis). Induction of septicemia produced a biphasic IL-1-response. A significant increase in IL-1 was seen peaking at 60 min, followed by a subsequent decrease. A second and more pronounced increase in IL-1 levels was seen 10 h after induction of septicemia in all animals, reaching a 100-fold increase compared to basal levels. Plasma exchange significantly lowered plasma IL-1 levels for 4 h after the exchange session. Neither extracorporal recirculation, nor leukapheresis significantly influenced IL-1 activity. A biphasic IL-1 release occurs during early gram-negative septicemia. It is possible to reduce these elevated IL-1 levels by plasma exchange, this is associated with improved cardiovascular status and prolonged survival.