Gene expression profiles in children under treatment for a malignancy presenting with neutropenic fever
By studying differently expressed immune genes with gene expression profiling in immune competent children researchers have been able to distinguish between children with asymptomatic viral infection and those with symptomatic viral infection as well as patients with bacterial infection. In this study we asked if gene expression profiling is feasible as a diagnostic tool in febrile neutropenia.  We included children under treatment for a malignancy presenting with febrile neutropenia. Clinical data regarding the infectious episode was prospectively collected and children grouped based on microbiological agent detected into virus, bacteria, co-infection and unknown aetiology. Fourty three episodes had sufficient RNA for RNA-sequencing, 15 with respiratory tract virus, 22 with unknown etiology, 4 with co-infection and 2 with bacteria. No pathogen specific host-innate immune expression profile was seen in the group with virus, bacteria nor unknown aetiology probably due to the low white blood cell account (WBC). In the co-infection group with higher WBC but lower absolute neutrophil count (ANC)  compared to the other groups, a downregulated innate response were detected. We conclude that gene expression profiling in children presenting with neutropenic fever is not a feasible diagnostic tool for febrile neutropenia in children with cancer due the low WBC.:  Overall design: RNA-sequencing of 43 episodes with febrile neutropenia grouped based on  microbiological agent detected and 12 controls.