Interleukin-18 serum levels in sepsis: Correlation with disease severity and inflammatory markers

•IL-18 has diagnostic significance in sepsis and septic shock patients.•IL-18 differentiates source of infection better than PCT, CRP and WBC.•IL-18 is sepsis biomarker with no prognostic significance. Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection and a syndrome shaped by pathogen and host factors with characteristic that evolve over time. The study was conducted to evaluate the prognostic and discriminative value of IL-18 assessment in comparison to PCT, CRP, WBC in early stage of sepsis and septic shock. An observational and prospective study was conducted in the group of 40 ICU patients with diagnosis of sepsis or septic shock, serum PCT, IL-18, CRP and WBC measurements were performed on admission, and on the 2nd, 3rd and 5th therapy day. The level of IL-18 was determined with commercially available test according to manufacturer’s protocol. There were no statistically significant differences in IL-18 levels in survivors vs non-survivors and in sepsis vs septic shock subgroups the IL-18 levels were statistically significant in the course of the study except for the 5th day. The PCT, CRP and WBC levels revealed no significant differences between any analyzed subgroups in all time points during study. According to our results the IL-18 is a biomarker better differentiating sepsis and septic shock status than PCT, CRP and WBC but with no prognostic impact.