Interleukin-6 and tumor necrosis factor-alpha levels in plasma and cerebrospinal fluid of term newborn infants with hypoxic-ischemic encephalopathy

OBJECTIVES: To determine plasma and cerebrospinal fluid (CSF) levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in hypoxic-ischemic encephalopathy (HIE). STUDY DESIGN: A controlled, prospective study of 20 control neonates, 19 term newborn infants presenting with sepsis and no meningitis, and 19 asphyxiated term newborn infants. Blood and CSF samples were collected within 48 hours of birth for IL-6 and TNF-alpha determinations. RESULTS: Median plasma IL-6 was similar in sepsis and asphyxia but significantly higher than in control neonates. Median plasma TNF-alpha was similar in asphyxia and control neonates but significantly lower than in sepsis. In asphyxiated newborn infants, median CSF IL-6 and TNF-alpha were significantly higher than in sepsis and control neonates. Median CSF IL-6 was significantly higher in sepsis than in control neonates. Median CSF TNF-alpha was similar in newborn infants with sepsis and control neonates. IL-6 and TNF-alpha CSF/plasma ratios were similar in newborn infants with sepsis and control neonates but lower than in asphyxiated newborn infants. CONCLUSIONS: Term newborn infants with HIE have elevated CSF IL-6 and TNF-alpha levels. Plasma IL-6 is increased in asphyxia and sepsis. Plasma TNF-alpha is increased only in sepsis. High IL-6 and TNF-alpha CSF/plasma ratios in asphyxia suggest that these cytokines are produced in the brain of term newborn infants with HIE.