Recently, neutrophils isolated from healthy adult donors were shown to undergo programmed cell death distinct from apoptosis and necrosis to form neutrophil extracellular traps (NETs). NETs are extensive lattices of extracellular DNA and chromatin decorated with anti-microbial proteins and degradative enzymes such as myeloperoxidase and neutrophil elastase (NE). NETs effect extracellular killing of bacteria and fungi. The laboratory of Christian Yost, MD recently characterized impaired NET formation as a novel innate immune deficiency of human newborn infants and showed that PMNs isolated from the cord blood of newborn infants, both term and preterm, demonstrated impaired NET formation and extracellular bacterial killing as compared to PMNs isolated from healthy adults. However, the timing for developmental maturation of newborn infant PMN NET formation remains unknown.