P451 Immune function in healthy male and female term infants

Abstract

Aims Male neonates appear to be more susceptible to infection than females. The immunological reasons for this are poorly understood. Our aim was to compare the immune response of healthy term male and female neonates using flow cytometry and cytokine analysis. Methodology Whole blood was collected with routine phlebotomy in healthy, term infants on the postnatal ward within 48 hours of delivery. Samples were processed for flow cytometry and cytokine analysis. Whole blood was treated with endotoxin (LPS; 10 ng/mL) for 1 hour at 37°C before subsequent analysis. Granulocytes and monocytes were identified by flow cytometry based on light scattering properties and cell surface markers. Multiplex ELISA was undertaken using a multisport 96-well plate customised for the experiment. Results In total 26 neonates were analysed (13 of each sex) with 20 having flow cytometry analysis and 6 undergoing ELISA. Female monocytes had higher CD11B expression than males following endotoxin stimulation. GM-CSF, IL-10, IL-1RA and IL-8 increased significantly following endotoxin stimulation in females but not males (p<0.05) Conclusion Male and female neonates mount different immune responses following septic challenge. Results suggest that females mount a more robust immune response and may be better able to modulate the immune response resulting from infectious stimuli.

Gender and Immune Function in Newborn Infants: The Role of Estrogen

“…Additionally, a significant association between male sex and mortality among blood culture positive preterm neonates has been described 25 . Recent data from our group has demonstrated GM-CSF, IL-10, IL-1RA and IL-8 increased significantly following endotoxin stimulation in healthy female neonatal whole blood but not in males 26 .…”