PURPOSE: Neonatal sepsis is an important public health concern worldwide due to 
its immediate lethality and long-term morbidity rates, Clinical evaluation and 
laboratory analyses are indispensable for diagnosis of neonatal sepsis. However, 
assessing multiple biomarkers in neonates is difficult due to limited blood 
availability. The aim is to investigate if the neonatal sepsis in preterm could 
be identified by multiparameter analysis with flow cytometry.
MATERIALS AND METHODS: The expression of activation-related molecules was 
evaluated by flow cytometry in newborn with or without risk factors for sepsis.
RESULTS: Our analysis revealed that several markers could be useful for sepsis 
diagnosis, such as CD45RA, CD45RO, or CD71 on T cells; HLA-DR on NKT or classic 
monocytes, and TREM-1 on non-classic monocytes or neutrophils. However, ROC 
analysis shows that the expression of CD45RO on T lymphocytes is the only useful 
biomarker for diagnosis of neonatal late-onset sepsis. Also, decision tree 
analyses showed that CD45RO plus CD27 could help differentiate the preterm 
septic neonates from those with risk factors.
CONCLUSIONS: Our study shows a complementary and practical strategy for 
biomarker assessment in neonatal sepsis.