Neutrophil chemotaxis in cord blood of term and preterm neonates is reduced in preterm neonates and influenced by the mode of delivery and anaesthesia.

Bacterial infections, even without any perinatal risk factors, are common in newborns, especially in preterm neonates. The aim of this study was to evaluate possible impairment of neutrophil chemotaxis in term and preterm neonates compared with adults as well as neonates with different modes of delivery and anaesthesia. We analysed the expression of the adhesion molecule L-Selectin as well as shape change, spontaneous and N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced transmigration of neutrophils in a flow cytometric assay of chemotaxis after spontaneous delivery with Cesarian Section (CS) under spinal anaesthesia (mepivacaine, sufentanil), epidural anaesthesia (ropivacaine or bupivacaine, sufentanil) or general anaesthesia (ketamine, thiopental, succinylcholine). Chemokinesis was higher (p=0.008) in cord blood neutrophils than in the adult ones, whereas those could be more stimulated by fMLP (p=0.02). After vaginal delivery neutrophils showed a higher spontaneous and fMLP-stimulated chemotactic response compared to neonates after CS without labor. Comparing different types of anaesthesia for CS, spinal anaesthesia resulted in less impairment on chemotaxis than general anaesthesia or epidural anaesthesia. The new flow cytometric assay of neutrophil chemotaxis is an appropriate and objective method to analyse functional differences even in very small volumes of blood, essential in neonatology. Term neonates do not show reduced chemotaxis compared to adults. Preterm neonates present with reduced chemotaxis and chemokinesis, confirming the well known deficits in their neutrophil function. The side effects of maternal drugs on the neonatal immune system have to be considered especially when the immune response is already impaired, as in preterm infants.

Age-related low expression of HLA-DR molecules on monocytes of term and preterm newborns with and without signs of infection.

OBJECTIVES: Presentation of human leucocyte antigen (HLA) molecules is an important part of an efficient immune response. Since bacterial infections are more common in newborns, we hypothesized that the level of HLA-DR expression may influence the host defense system. STUDY DESIGN: HLA-DR expression on monocytes was examined by flow cytometry during the first week of life of term and preterm neonates with and without signs of infection and of adults. RESULTS: HLA-DR expression of term and preterm newborns with or without signs of infection was lower compared with adults during the first day of life (p<0.0001). Prematurity correlates with lower expression in neonates with gestational age less than 32 weeks (p=0.0008). HLA-DR expression in neonates with signs of infection was decreased compared to healthy neonates (p=0.0196). Maternal conditions such as preeclampsia, prenatal treatment with steroids and mode of delivery had no influence on the expression of HLA-DR. In contrast, newborns with respiratory distress syndrome but without signs of infection showed reduced HLA-DR expression (p=0.0370). CONCLUSION: Low HLA-DR expression on monocytes contributes to impaired neonatal host defense, especially in preterm neonates.

Drotrecogin alpha (activated) in neonatal septic shock.

A 12-d-old neonate suffering from group B streptococcal septic shock was treated with 24 microg/kg/h recombinant human activated protein C [rhAPC, drotrecogin alpha (activated)] for 96 h. The protein C activity increased from 5% to 53% after rhAPC infusion. The patient recovered within 14 d without any adverse effects.