Effect of granulocyte and granulocyte macrophage colony stimulating factors (G-CSF and GM-CSF) on neonatal neutrophil functions

Although there are many studies on the effect of granulocyte and granulocyt e-macrophage colony stimulating factors (G/GM-CSF) on adult neutrophil func tions, there is little information regarding their influence on neonatal ce lls. We studied the in vitro effect of G/GM-CSF on neutrophil chemotaxis, p olarization, and superoxide anion generation in 47 neonates compared with 3 5 adults. We found that G-CSF and GM-CSF significantly enhanced the chemota xis of newborn infants' neutrophils, normalizing their chemotactic defect [ from 35 +/- 7 cells/field (mean +/- SE) to 49 +/- 5 cells/field with G-CSF, p < 0.05 and to 55 +/- 4 cells/field with GM-CSF, p < 0.001]. It is notabl e that the maximal neutrophil response to the cytokines was observed partic ularly in the newborn infants with severe impairment in their chemotactic a ctivity. Statistical analysis of the data showed a significant inverse corr elation, which supported this observation (r = -0.6, p < 0.02 for G-CSF; r = -0.76, p < 0.001 for GM-CSF). The reduced polarization of neonatal compar ed with adult cells [71 +/- 5% versus 86 +/- 2% (mean +/- SE), p < 0.05], w as corrected by CSF-priming (to 87 +/- 4% with G-CSF and to 92 +/- 2% with GM-CSF, p < 0.05). In addition, the neutrophil superoxide generation was si gnificantly improved in both groups following the CSF-priming. GM-CSF and G -CSF gave comparable results in all functions studied except that GM-CSF im proved superoxide release to a greater extent. This study shows a significa nt improvement of the neonatal neutrophil functions following in vitro CSF- priming and contributes to a better understanding of the neonatal neutrophi l behavior when treated with G/GM-CSF.