Impairment of stimulation ability of very-preterm neonatal monocytes in response to lipopolysaccharide.

Little is known about innate immunity of neonates, particularly for very-preterm ones, which are more susceptible to immunologic damage due to their immature immune response. This cross-sectional, descriptive study in umbilical cord blood mononuclear cells describes the differences in innate immune response between 64 healthy neonates of different gestational ages (very-preterm, preterm, full-term). CD14(+) monocytes cultured with lipopolysaccharide (LPS) or LPS + interferon-gamma showed significant lower human leukocyte antigen-DR percentages for the very-preterm group in both unstimulated and LPS-stimulated cells. No differences were found for CD40(+)-cell percentages. We observed an increase in CD80 and a decrease in CD86 within all groups when stimulated with LPS or LPS + interferon-gamma. Interleukin-12 production was lower in very-preterm neonates. Adhesion capability of neonatal monocytes was similar and independent of gestational age. In summary, very-preterm-neonatal monocytes do not completely respond to LPS and, therefore, have diminished functions compared with preterm or full-term neonates.