Is there an effect of immunoglobulins and G-CSF on neutrophil phagocytic activity in preterm infants?

The percentage of neutrophils phagocytosing group B streptococci (GBS) in v itro was determined in ten healthy preterm infants (< 32 weeks of gestation ) and adult controls by using an acridine orange fluorescence whole blood a ssay. When GBS were opsonized with adult serum, no difference in phagocytic activity was found between both groups after 10 and 30 min (preterms: 40% and 68%, adults: 32% and 56%, respectively). Phagocytosis rates in preterm infants decreased significantly to 6% and 18% (at 10 and 30 min) when pool serum of preterm infants was used instead. Supplementation of the preterm s erum with either intravenous immunoglobulin or IgM-enriched immunoglobulin did not change the results significantly. The addition of granulocyte colon y-stimulating factor (G-CSF) accelerated phagocytosis significantly after 1 0 min, but did not increase the overall phagocytic activity after 30 min in either group. Hence the potential benefits of intravenous immunoglobulins and G-CSF in neonatal sepsis may not be attributable to an immediate increa se in and direct effect on neutrophil phagocytic activity.