Latex phagocytosis by polymorphonuclear leukocytes. In vitro and in vivo studies with a simple screening test.

A simple semiquantitative slide test to assess the phagocytic activity of periphera polymorphonuclear leukocytes is described. Leukocytes are isolated from one drop of blood and latex particles are offered for phagocytosis. Cellular capacities and serum opsonins can be assessed separately. In the presence of pooled adult serum no defect of phagocytosis was seen in preterm and full-term newborns nor in pediatric patients with infectious or other diseases. In 4 of 7 premature newborns a definite deficiency of serum opsonins was demonstrated. In in vitro studies complement (plus possibly other heat-labile factors) promoted phagocytosis. Phagocytic rates were depressed by endotoxin and phenylbutazone.