Interleukin-8 as a predictor of the severity of bacteremia and infectious disease

The relationship between cytokines and sepsis has been studied frequently in the intensive care unit (ICU). However, the determination of cytokines in patients as they enter the emergency department (ED) would be more meaningful in predicting the outcome of infection. This study investigated plasma interleukin-8 in the ED as the predictor of bacteremia and sepsis. One hundred patients admitted through the ED with signs of systemic inflammatory response syndrome were studied. Plasma IL-8, IL-6, and tumor necrosis factor (TNF) were assayed by enzyme-linked immunosorbent assay. Patient's data were evaluated using the APACHE II scoring system as predictive factors of morbidity and mortality. Plasma IL-8 (149 pg/mL) detected bacteremia with a positive predictive value of 90.9% and a specificity of 98.7%. Results indicated that the odds ratios (ORs) of bacteremia were 24.78 (P < 0.01, CI = 2.27-270.8), 5.42 (P < 0.05, CI = 1.37-21.4), and 6.05 (P < 0.05, CI = 1.36-26.8) for IL-8, IL-6, and APACHE II, respectively. Occurrence of bacteremia was highly correlated with increases in plasma IL-8 (P < 0.01). IL-8 (OR = 8.25, CI = 1.03-65.9) and APACHE II scores (OR = 12.6, CI = 2.24-70.4) were found to be significantly better predictive factors of mortality (P < 0.01) than IL-6 (OR = 3.60, CI = 0.57-22.7), TNF (OR = 0.24, CI = 0.01-11.0) and age (OR = 1.02, CI = 0.98-1.06). During bacteremia, IL-8 also correlated well with patient use of a ventilator (P < 0.01, OR = 2.43, CI = 2.41-311.19), use of vasopressors (P < 0.05, OR = 2.67, CI = 1.79-370.78), length of stay in the hospital (P < 0.01, OR = 3.14, CI = 1.87-988.31), and stay in the ICU (P < 0.01, OR = 2.51, CI = 2.98-449.80). Measuring IL-8 on patients in the ED with apparent bacterial infections appears to be a reliable predictor of bacteremia and the severity of disease.