Interleukin-6 (IL-6) and soluble receptors for interleukin-2 (sIL-2R) in the diagnosis of early severe infection in the critically ill newborns.

The aim of our study was to evaluate the diagnostic accuracy of serial determination of interleukin-6 (IL-6) and soluble receptors of interleukin-2 (sIL-2R) in the diagnosis of early infection in the critically ill newborns and compare it with the routinely used C-reactive protein (CRP). Fourty-six critically ill newborns (median age 8 h, range 1-96 h), treated at the multidisciplinary intensive care unit, Division for Paediatric Surgery and Intensive Care, University Medical Centre Ljubljana, were included in the study. Newborns were divided into three groups: group I microbiologically confirmed severe infection (n = 14), group II suspected but not confirmed infection (n = 12) and group III respiratory distress syndrome without laboratory signs of infection. Serum concentrations of IL-6, sIL-2R and CRP were determined on admission and at 12 and 24 h after admission. On admission the concentrations of IL-6 and sIL-2R were significantly higher in group I than in group III, but there was no difference between groups I and II. On admission area under receiver operating characteristic (ROC) curve for IL-6 was 0.756, for IL-2R 0.821 and for CRP 0.799. Repeated determination at 12 h improved diagnostic accuracy for sIL-R and CRP but not for IL-6.