Interleukin-8 serum levels at fever onset in patients with neutropenia predict early medical complications

Background: Previous studies have shown that interleukin-8 serum levels in febrile neutropenic patients are significantly higher in patients with gram-negative bacteremia than in patients with other causes of fever and may indicate unfavorable outcomes. We assessed the value of interleukin-8 serum Levels at fever onset to predict clinical complications in order to confirm these earlier findings. Patients and Methods: In a prospective observational study of adult patients receiving cancer chemotherapy, serum samples obtained at the onset of 147 febrile neutropenic episodes were measured by an immunoluminescence assay. Results: Complicated courses of fever including severe sepsis or septic shock, respiratory insufficiency or death were observed in 13 episodes (9%); in six episodes complications had developed within 1 week after fever onset and five of them were associated with bloodstream infections. At an interleukin-8 cutoff level of 1,000 pg/ml, these early complications were predicted with a sensitivity of 83%, a specificity of 97%, a positive predictive value of 50%, and a negative predictive value of 99%, respectively. Conclusion: Interleukin-8 levels at fever onset may be used for the prediction of early medical complications associated with bacteremia and can help identify patients who might benefit from intensive care admission.