G-CSF, GM-CSF and IL-6 levels in cord blood: diminished increase of G-CSF and IL-6 in preterms with perinatal infection compared to term neonates.

AIM: The objectives of this study were 1) to clarify the physiologic regulation of cytokines such as IL-6, G-CSF and GM-CSF in preterm and term neonates and 2) to evaluate the influence of perinatal stress and infection on endogenous cytokine levels. METHOD: We examined cord blood levels of G-CSF, GM-CSF and IL-6 using a bioassay in 43 term and 44 preterm neonates. RESULTS: Compared to normal neonates (G-CSF: mean (m) = 97.6 +/- 16.3 pg/ml; IL-6: m = 20.2 +/- 4.6 pg/ml), we found elevated G-CSF levels in newborns with perinatal stress (m = 247.1 +/- 72.1 pg/ml; p = 0.003) and increased levels for G-CSF (m = 8980.9 +/- 4388 pg/ml; p = 0.0003) and IL-6 (m = 705 +/- 322.3 pg/ml; p = 0.025) in neonates with infection. Term newborns with infection had higher G-CSF levels than preterms (m = 15575 +/- 9374 pg/ml versus m = 5384.1 +/- 4470.9 pg/ml; p = 0.024). G-CSF levels of newborns with infection were correlated with birth weight (r = 0.50; p = 0.024) but not with gestational age (r = 0.40; p = 0.057). GM-CSF was only detectable in cord blood in 4 cases of normal healthy neonates. CONCLUSIONS: The response of G-CSF levels in preterms to infection is diminished. Body cell mass is more important than gestational age to provide high G-CSF levels during states of infection.