Neutrophil function in newborns.

Abstract

Neutrophil function was studied in prematures, mature newborns and school children.In premature infants, chemotaxis and killing of neutrophils were decreased, although superoxide production of neutrophils was normal. In healthy full-term infants, only chemotaxis was abnormal.The ability of neutrophil phagocytosis was within normal limits both in premature and mature newborns. neutrophil; chemotaxis; phagocytosis; killing; newborn Many workers (Stiehm and Fudenberg 1966;Miller 1971) have drawn attention to immaturity of specific and nonspecific immune mechanisms in early childhood. However, the study of neonatal neutrophil function in every stage including metabolic activity for the same material has never been reported. Authors divided the neutrophil function to three stages; chemotaxis, phagocytosis and killing. As for phagocytosis, a phagocytic test and a bioassay of tuftsin (phagocytosis stimulating peptide) were done. To clarify the metabolic activity of neonatal neutrophil, superoxide production was also measured besides the nitroblue tetrazolium (NBT) reduction test. MATERIALS AND METHODSCord blood was obtained from 20 premature infants (30-36 weeks of gestaton, 1,650-2,250 g birth weight) and 20 term infants (38-40 weeks of gestation, 2,600-3,950 g birth weight).All of the neonates were healthy. No antibiotics nor medications other than anesthesia had been administered prior to delivery. The venous blood of 20 healthy school children of both sexes aged between 6 and 12 years was obtained by venipuncture. Heparinized blood samples were processed within 3 hr after collection.Skin window response was done by the method of Rebuck and Crowley (1955) as modified by Eitzman and Smith (1959). Premature and mature infants between 10 to 24 hr after birth and school children who had no evidence of a skin rash or infection were studied. The skin was cleaned with alcohol, then the superficial epidermis was scraped with a sterile scalpel blade. A sterile thin cover glass was placed over the abraded surface. The cellular exudate on the surface of the cover slip was stained with May and Giemsa stains, and differential cell counts were made of at least 500 cells.Chemotactic assay was done by using Wilkinson's modification (1974) of the Boyden technique.The attractant used was cultured filtrate of E. coli. Random migration was assessed in the absence of a concentration gradient. 20% serum was added to both the upper

Nitroblue Tetrazolium Reduction Test and Serum Lysozyme Assay in Newborn Arabian Foals and Mares

“…There were no age-related changes in this activity during the first 3 weeks of life, whereas in the mares a significant positive correlation between the results of the NBT test and time post partum was found. 17,9), jedoch war das LZM-Phagozytenverhaltnis bei Fohlen und Stuten gleich.…”

“…Es traten wahrend der ersten 3 Lebenswochen keine altersabhangigen Unterschiede in dieser Aktivitat auf, wahrend bei den Stuten eine deutliche positive Korrelation zwischen den Ergebnissen des NBT-Testes und der Zeit post partum gefunden wurde. 17,9), alors que le rapport LZM/phagocytes fut le m&me chez les poulains et les juments.…”

“…Una actividad LZM claramente mds baja (P < 0,05) se ha116 en 10s potros que eran mayores que 24 horas, en comparaci6n con 10s valores medidos en las yeguas (40,84 U/ml k 15,32 y 48,96 U/ml +. 17,9), mientras que la relaci6n LZM/fagocitos era igual en 10s potros y en las yeguas.…”