Endotoxin-stimulated production of IL-6 and IL-8 is increased in short-term cultures of whole blood from healthy term neonates

To assess the stimulated production of Interleukin-6 and Interleukin-8 in healthy term neonates compared to adults, and to study the effect of labour on the capacity of cytokine secretion, 20 healthy term neonates (11 delivered by elective caesarean section, (ECS) group; 9 vaginally delivered, (VD) group) were included in the study, and five healthy adult volunteers served as controls. Spontaneous and lipopolysaccharide (LPS)-stimulated IL-6 and IL-8 secretion in short-term umbilical whole blood cultures was determined. Spontaneous IL-6 (IL-8) secretion was detected in only a few samples with maximum levels of 14 (23) pg/ml. After 4 h of LPS incubation median IL-6 levels increased to 2026 (339-2547) pg/ml (VD group) and 1670 (704-2037) pg/ml (ECS group). Median IL-8 concentration after LPS stimulation was 2142 (738-4053) pg/ml in the VD group and 1483 (1036-2934) pg/ml ECS group. Interleukin-6 and IL-8 levels following LPS-stimulation in both groups markedly exceeded the values of adult controls. Stimulated cytokine secretion showed no significant difference between VD and ECS groups. Spontaneous cytokine production in cord blood is variable and related to individual cytokine expression and regulation. The pro-inflammatory response to endotoxin as determined by ex vivo LPS-stimulation of short-term whole blood cultures of term neonates, in contrast to spontaneous cytokine secretion, exceeds adult levels and appears to be independent of the mode of delivery and labour.