Distinct mitochondrial respiration profiles in pediatric patients with febrile illness versus sepsis

Mitochondrial dysfunction, linked to sepsis-related organ failure, is unknown in febrile illness. Prospective study of children in an Emergency Department (ED) with febrile illness or without infection (ED controls); secondary analysis of ICU patients with sepsis or without infection (ICU controls). Mitochondrial oxygen consumption measured in peripheral blood mononuclear cells using respirometry, with primary outcome of spare respiratory capacity (SRC). Mitochondrial content measured as citrate synthase (CS: febrile illness and ED controls) and mitochondrial to nuclear DNA ratio (mtDNA:nDNA: all groups). SRC was lower in febrile illness (6.7 ± 3.0 pmol/sec/10 cells) and sepsis (5.7 ± 4.7) than ED/PICU controls (8.5 ± 3.7; both p