Biochemical and inflammatory aspects in patients with severe sepsis and septic shock: The predictive role of IL-18 in mortality

•IL 18 is an important predictor of mortality in septic patients. The association of IL-18 and increased mortality rates is independent of IL-1β.•NO is not involved in the higher mortality observed in the septic shock group.•Tissue lactate production was not related to the higher mortality in the septic shock group

BackgroundSepsis is a major health care problem, with a significant mortality rate in intensive care units. We evaluated biochemical and inflammatory markers in patients with severe sepsis and septic shock and its association of with mortality rates.MethodsCritically ill patients with diagnoses of sepsis - severe sepsis group (n = 23) and septic shock group (n = 25), and a control group (n = 17) were recruited within 24 h of entry into the ICU. Serum levels of inflammatory mediators were measured (IL-1β, IL-6, IL-8, IL-10, TNF-α, IL-18 and nitric oxide). We have also collected clinical parameters and laboratorial tests to estimate severity and organ dysfunction (APACHE II, SOFA, lactate). These results were compared between survivors and no survivors.ResultsIL-18 was directly related to mortality independently of other inflammatory mediators, especially IL-1β, although the inflammatory pathway is closely linked to inflammasome activation and both have simultaneous release in the infectious process. Mortality was directly proportional to IL-18 plasma levels, which did not occur with other inflammatory mediators.ConclusionsIL-18 is an important predictor of mortality in humans with both severe sepsis and septic shock, independent of IL-1β.