Circulating mitochondrial DNA levels are associated with early diagnosis and prognosis in patients with sepsis

To the Editor:Both pathogen-associated molecular patterns and damage-associated molecular patterns(DAMPs)are known to enhance levels of inflammation and tissue injury during sepsis.Mitochondria are a major source of DAMPs because they release mitochondrial(mt)DNA fragments during sepsis.Similar to bacterial DNA,circulating mtDNA can activate signaling pathways and promulgate inflammation.Previously,Puskarich et al[1]found no significant elevation in the levels of plasma mtDNA in patients presenting to the emergency department with sepsis and septic shock.However,Schäfer et al[2]found that serum mtDNA significantly increased in septic patients compared with controls.Moreover,our previous study showed that circulating mtDNA levels within 24 h after admission were significantly increased in the group of septic patients with acute lung injury.[3]Thus,it remains unclear whether changes in mtDNA during sepsis are of clinical relevance.This study aimed to determine whether circulating mtDNA within 24 h of intensive care unit(ICU)admission can be used as a marker for the early diagnosis and prognosis of sepsis.