Serum levels of CD14 in neonatal sepsis by Gram-positive and Gram-negative bacteria

The purpose of this study is to measure soluble CD14 (sCD14) levels in sera from newborn with sepsis, to compare it with other markers, and to study its evolution in Gram-negative and Gram-positive sepsis. Forty normal newborns were included (26 were full term and 14 were preterm infants), 20 babies had a positive blood culture (11 Gram-positive and 9 Gram-negative) and 16 cases were suspected of having sepsis based on clinical and laboratory findings, but a negative blood culture. Interleukin-6 (IL-6), sCD14, and tumour necrosis factor-α (TNFα) were measured by enzyme immunoassay, and fibronectin (FN) and C-reactive protein (CRP) by radial immunodiffusion. Neonates with a positive blood culture had increased levels of sCD14(3.20 ± 1.26μgml^-1, p < 0.001), CRP(69 ± 46 μgml^-1, p < 0.001)and IL-6 (134 ± 150 pg ml^-1, p < 0.001), and decreased values of FN (12.3 ± 6.6 mg ml^-1, p < 0.001). TNFα levels were also high (160 ± 37 pg ml^-1), but this increase was not statistically significant. Newborn infants suspected of having sepsis but a negative blood culture had similar but milder abnormalities. Soluble CD 14 levels correlated with CRP values; however, there was no correlation between sCD 14, TNFα and IL-6. Neonates with sepsis by Gram-positive bacteria had lower sCD14 levels than patients with Gram-negative sepsis (2.63 ± 1.2 versus 4.04 ± 1.0μgml^-1, p < 0.05). In conclusion, the sCD14 level is increased in newborn infants with sepsis, and this is higher in infections by Gram-negative bacteria, suggesting a different contribution of monocyte and macrophage cells. In contrast, IL-6, TNFα, CRP and FN values are similar in infections by Gram-positive and Gram-negative bacteria.