CLINICAL ROLE OF CIRCULATING INTERLEUKIN-8 IN PATIENTS WITH BACTERIAL INFECTION

The cytokine network is activated in the pathogenetic mechanisms of septic diseases. We measured serum concentrations of interleukin (IL)-8, a leukocyte-mediated cytokine, in 152 patients with culture-proven or suspected septicemia and 25 control subjects. The IL-8 concentrations in patients who were diagnosed as septicemia were significantly higher than those in controls. IL-8 concentrations in septic patients with negative blood cultures were also significantly higher than in controls. In addition, serum IL-8 concentrations were assayed prospectively in 3 patients undergoing chemotherapy for acute myelogenous leukemia. Increased IL-8 concentrations preceded onset of fever and elevation of C-reactive protein by 1 day. Finally, to investigate modulation of cytokine release in vitro, U937 human monocytic leukemia cells were stimulated with phorbol 12-myristate 13-acetate (PMA), lipopolysaccharide (LPS), or lipoteichoic acid (LTA). IL-8 mRNA expression was detected by reverse transcription-polymerase chain reaction 30min after PMA or LPS exposure, and IL-8 was secreted into culture media 3 hr after PMA, LPS, and LTA stimulation. These data suggest that IL-8 is a useful early indicator of bacterial infection.