Human polymorphonuclear leukocyte function in urine

Leukocyte migration, adhesion to glass, aggregation by endotoxin, and phagocytosis of bacteria were virtually abolished in urine. Suppressed leuklcyte function in urine appeared to be mediated by direct toxic effects of urine on leukocytes. Such effects were, in part, attributable to extremes of osmolality, pH, urea concentration, and to an as yet unidentified toxic factors(s) present in normal urine. Leukocyte function in plasma was not impaired by incubation in buffered electrolyte solution or in iso osmotic urine adjusted to pH 7.5. Thus, cell injury in urine was not attributable to removal of leukocytes from the plasma environment. Under conditions which minimized cell injury, it was possible to demonstrate that the impaired phagocytic capacity of leukocytes in urine was in part due to lack of serum opsonins necessary for optimal phagocytosis.