Sequential changes in human polymorphonuclear leukocytes after urate crystal phagocytosis. An electron microscopic study

Monosodium urate crystals added to human polymorphonuclear leukocytes are rapidly phagocytized. Crystals initially lie within phagosomes with a distinct, closely approximated phagosomal membrane. By 8 minutes phagolysosome distension is seen in some cells, degranulation begins, and phagolysosome membrane dissolution is seen. By 30 minutes there are many cell deaths with release of ingested crystals and cellular contents. Urate crystals have a profound and rapidly toxic effect on isolated leukocytes. The loss of phagolysosome membranes may be important in producing cell death.