Phagocytosis of neonatal pathogens by peripheral blood neutrophils and monocytes from newborn preterm and term infants

Amy Prosser, Julie Hibbert, Tobias Strunk, Chooi Heen Kok, Karen Simmer, Peter Richmond, David Burgner, Andrew Currie

Research output: Contribution to journalArticleResearchpeer-review

30 Citations (Scopus)

Abstract

Background:Deficiencies in phagocytosis may contribute to the increased susceptibility of infants to early life infections. Data on phagocytosis of the major neonatal pathogens Staphylococcus epidermidis (SE), Staphylococcus aureus (SA), and Escherichia coli (EC) by preterm infant leukocytes are inconsistent.Methods:Cord and <24-h peripheral blood were collected from very preterm (<30.1 wks gestational age (GA)) and term (37-42 wks GA) infants. Monocyte and neutrophil phagocytosis of pHrodo-labeled SE, SA, and EC were analyzed using a small-volume flow cytometry assay, with simultaneous characterization of surface activation marker expression.Results:Preterm infants had lower proportions of monocytes and neutrophils capable of phagocytosis than term infants, but preterm infant phagocytes had higher phagocytic capacity. Phagocytosis was strongly correlated between cord and <24-h peripheral blood. Supplementation with exogenous complement significantly increased phagocytosis of EC but not of SE or SA. Monocyte human leukocyte antigen (HLA)-DR expression was lower in preterm infants but did not correlate with phagocytosis.Conclusion: There is no defect in phagocytosis by monocytes and neutrophils from preterm compared with term infants, although preterm infants possess fewer phagocytes, possibly contributing to susceptibility to bacterial infection. Further investigation into the development of postnatal phagocytic competence is warranted.

Original languageEnglish
Pages (from-to)503-510
Number of pages8
JournalPediatric Research
Volume74
Issue number5
DOIs
Publication statusPublished - Nov 2013
Externally publishedYes

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