Early life response to infectionGhazal, Petera,b; Dickinson, Paula,b; Smith, Claire L.a,cCurrent Opinion in Infectious Diseases: June 2013 - Volume 26 - Issue 3 - p 213–218 doi: 10.1097/QCO.0b013e32835fb8bf PAEDIATRIC AND NEONATAL INFECTIONS: Edited by Paul T. Heath Buy Abstract Author InformationAuthors Article MetricsMetrics Purpose of review Sepsis is a serious complication in preterm and term infants, yet our understanding of how neonates respond to infection remains poorly defined. Recent findings We describe our current clinical, cellular and molecular understanding of the neonatal host systemic response to infection. We find that host resilience essentially relies on innate immune mechanisms despite there being a complete repertoire of cellular components of the adaptive immune arm. The functional interplay between metabolism, immunity and microbiome further suggests that neonatal vulnerability to infection is not simply due to immaturity of the immune system but how immune homeostasis is regulated. Further research is required for exploring regulatory homeostatic mechanisms between innate and adaptive responses and microbiome colonization at birth, but which can impart an adverse trajectory to infection. Summary The vulnerability and resilience against infection in neonates, including extreme preterm infants, still remains poorly understood. We advance the view that greater consideration should be given to understanding the set point in the regulation of homeostatic control of innate and adaptive immunity and its interplay with metabolism and the newly acquired microbiome. aDivision of Pathway Medicine, University of Edinburgh bSynthSys – Synthetic and Systems Biology, University of Edinburgh cNeonatal Unit, Simpson Centre for Reproductive Health, Royal Infirmary of Edinburgh, Edinburgh, UK Correspondence to Peter Ghazal, Division of Pathway Medicine, 49 Little France Crescent, University of Edinburgh, EH16 4SB, UK. Tel: +44 131 2426288; e-mail: email@example.com © 2013 Lippincott Williams & Wilkins, Inc.