Apoptosis of leukocytes: Basic concepts and implications in uremia

Circulating blood leukocytes have short life expectancies and end their liv es by committing programmed cell death or apoptosis. Apoptosis is an active form of cell death that is initiated by a number of stimuli and is intrica tely regulated. Apoptosis in both excessive and reduced amounts has patholo gical implications. Evidence suggests that apoptosis may play a role in the pathophysiology of immune dysfunction in uremia. Indeed, accelerated progr ammed cell death has been observed in lymphocytes, monocytes, and polymorph onuclear leukocytes among patients with chronic renal failure. This may be due in part to the retention of uremic toxins. The aim of this article is t o review the evidence for accelerated leukocyte apoptosis, key regulatory a poptotic pathways, and the possible role of this highly organized process i n the pathogenesis of immune dysfunction in uremia.