Introduction Newborn infants are at risk of vitamin D deficiency and various studies implicate vitamin D as having immunomodulatory effect. Adequate generation of reactive oxygen intermediates (ROI) by neutrophils (PMN) during sepsis is bactericidal. However, production of neutrophil oxidase activity in the presence of sepsis is impaired in neonates.
Aim To examine the in vitro effect of 1, 25(OH)2D3 on whole blood PMN and monocyte ROI, TLR4, CD11b in newborn infants during sepsis in vitro .
Methods Whole blood from preterm infants <32 weeksgestation within 24 h of birth, cord blood from term infants and adult controls were analysed for phagocytic expression of Toll-Like Receptor 4 (TLR4; pathogen recognition); CD11b (chemotaxis and adhesion) and ROI production (bacterial kill) using flow cytometry. These were assessed in response to Lipopolysaccharide (LPS; Endotoxin; in vitro sepsis) and 1,25(OH)2D3.
Results ROI production from preterm and term neonatal neutrophils incubated with LPS alone was not significantly increased in contrast to adults. However pre-incubation with 1,25(OH)2D3 before adding LPS demonstrated a significant increase (p = 0.001) in ROI production for both preterm and term infants while simultaneous LPS and 1,25(OH)2D3 had no effect.
Conclusion New born infants were hypo-responsive in the presence of sepsis in vitro which recovered on pre-treatment with 1, 25(OH)2D3. Pre-treatment with vitamin D may improve term and preterm infants’ antibacterial responses.