Circulating concentrations of chemokines in cord blood, neonates, and adults.

Chemokines are critical for the movement of leukocytes. Chemotaxis is deficient in neonates, particularly those delivered prematurely, and this likely contributes to their increased vulnerability to sepsis. The concentrations of circulating chemokines in neonates have not been reported, nor is it known whether low chemokine concentrations contribute to their defective chemotaxis. We hypothesized that serum concentrations of chemokines 1) would be lower in preterm than term neonates, and 2) would be lower in preterm and term neonates than adults. Samples were obtained from preterm and term neonates with normal neutrophil and eosinophil counts, umbilical cord blood samples from pregnancies without clinical evidence of intra-amniotic infection, and healthy adult volunteers. The concentrations of epithelial neutrophil activating peptide-78, growth-related oncogene-alpha, eotaxin, RANTES (regulated upon activation, normal T cell expressed and secreted), and macrophage inflammatory protein-1 alpha were measured using specific ELISA. Serum concentrations from preterm infants were either similar to or higher than those measured in term neonates and adults. We conclude that the chemotactic defect observed in premature neonates is not the result of diminished circulating concentrations of any of the specific chemokines we measured.