Background: Neutrophils are central to the defence against infection; in newborns, production and function are immature. Intrauterine growth restriction increases the risk of both neutropenia and sepsis. We report clinical outcomes of a randomised controlled trial of prophylactic GM-CSF in babies born below 32 weeks gestation.

Subjects & interventions: Twenty five appropriately grown(AG) and 19 growth restricted (GR) infants have been randomised to date to receive recombinant granulocyte-macrophage colony stimulating factor (GM-CSF)(Leucomax, Sandoz), 10μg/kg daily, subcutaneously for 5 days, commencing within 72 hours of birth, or to a control group. Birthweight and gestational age, as median (range), were treatment (n=23) 1.1 kg (0.570,1.476) and 28 weeks (23,31); control (n=22) 0.920 (0.480,1.290) and 27 (24,30).

Results: There were no adverse effects attributable to GM-CSF; in particular, no difference in oxygen requirement at 36 weeks post menstrual age (p=0.34). No treated babies developed neutropenia in contrast to 8 (2 AG; 6 GR) in the control group (p=0.0015). Sepsis precipitated neutropenia in 3 control GR babies only. Though there was no significant difference in mortality from all causes, there were 3 deaths from sepsis in the control group and 1 in the treatment group. No AG infant died of sepsis.

Conclusions: Prophylactic treatment of preterm neonates with GM-CSF is safe, completely abolishes the postnatal neutropenia of GR babies and may decrease mortality from sepsis.