Interleukin 6, but not tumour necrosis factor-alpha, is a good predictor of severe infection in febrile neutropenic and non-neutropenic children with malignancy

OBJECTIVE: Interleukin-6 (IL6), tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) are important mediators of the inflammatory response in human infection. The aim of this study was to determine the relationship between serum levels of IL6, TNF-alpha, IFN-gamma and CRP in febrile children with malignant disease, and relate these levels to aetiology of fever, presence of neutropenia and the effect of untreated malignancy. METHODS: 110 febrile episodes in 70 children with malignant disease were included. Cytokine analyses were performed with sensitive immunoradiometric methods using double monoclonal antibodies. RESULTS: IL6 had a sensitivity of 74% in detecting sepsis in children with fever and malignant disease. This sensitivity was not influenced by the presence of neutropenia or newly diagnosed malignancy. A positive correlation between IL6 and the CRP levels on the following day was observed (r = .53). TNF-alpha was elevated in 22% of the episodes and mean levels were significantly higher in untreated malignancy but lower in neutropenic patients. IFN-gamma was elevated in 18% of cases and correlated strongly with mean TNF-alpha levels. CONCLUSIONS: IL6 is a sensitive and early predictor of bacterial infection in both neutropenic and non-neutropenic febrile children with malignancy. It is more sensitive than CRP in detecting sepsis, but the predictive value is too low to allow IL6 levels to influence initial treatment decisions in patients with granulocytopenia. TNF-alpha production seems to be impaired in neutropenic children and serum TNF-alpha cannot be employed as an indicator of bacterial infection.