The role of haemopoietic colony- stimulating factors in the management of newborn infection

Characteristics of neonatal neutrophils Polymorphonuclear neutrophils (PMN) are key components of the innate immune system, provide first line immune defence mechanisms against pathogenic challenge, and are both quantitatively and qualitatively deficient in neonates. Neutrophil deficiencies contribute significantly to the increased susceptibility of neonates to serious and overwhelming bacterial and fungal infections. Although circulating absolute neutrophil counts (ANC) may not differ greatly from those in older children and adults, the release of marrow reserves in response to systemic infection can be markedly impaired as a result of depletion of the neutrophil storage pool, held in reserve within the bone marrow. Severe neonatal sepsis may thus result in neutropenia, often with fatal consequences.