The role of the human polymorphonuclear leukocytes (PMNs) in the acute inflammatory response is well documented. PMNs play a fundamental role in the innate immune response and are rapidly recruited to areas of injury or inflammation where they participate in bacterial phagocytosis and killing. Disorders associated with a deficiency or impairment of PMN function (neutropenia, chronic granulomatous disease (CGD), leukocyte adhesion deficiency) predispose to infections with bacteria and fungi. Regulation of this potent component of the acute inflammatory response is imperative to prevent overwhelming infections often associated with morbidity and mortality.