ABSTRACT
We compared lymphocyte subsets and cytokine responses to bacteria among term, preterm infants, and adults. Lymphocyte subset percentages in cord blood (22 preterm, 27 term neonates) and peripheral blood from 21 adults and cytokine/chemokine interleukin (IL)-6, IL-8, IL-10, IL-12, interferon gamma (IFN gamma) responses to Escherichia coli, group B Streptococcus (GBS), Staphylococcus epidermidis, and Lactobacillus plantarum (Lp299v) were assessed by flow cytometry. Preterm compared with term infants had increased CD8 (+) T cells (p = 0.02) and reduced naïve CD4 (+) T cells (p < 0.0001). Memory T and natural killer (NK) T cells were reduced (p < 0.001) in neonates; NK and CD56 (+)161 (+) NK cells were increased (p < 0.001). CD56 (+)CD8 (+) NK cells were higher in preterm compared with term infants. Despite individual exceptions, cytokine responses in neonates were weaker than adults except for IL-8 response to E. coli in preterm and IL-12 response to Lp299v in term infants. IL-10 responses were weaker in preterm (p = 0.01) and term (p = 0.005) infants to S. epidermidis and to E. coli (p = 0.03 for both) compared with adults. Differences in regulatory subpopulations of NK and T cells between neonates and adults and term compared with preterm infants were observed. These differences rather than intrinsic functional deficiency may account for neonatal cytokine responses to bacteria.
Subject(s)
Antigens, Bacterial/pharmacology , Cytokines/metabolism , Fetal Blood/cytology , Lymphocyte Activation/immunology , Adult , Cells, Cultured , Chemokines/immunology , Chemokines/metabolism , Confidence Intervals , Cytokines/immunology , Female , Fetal Blood/immunology , Humans , Infant, Newborn , Infant, Very Low Birth Weight , Interleukin-10/immunology , Interleukin-10/metabolism , Interleukin-12/immunology , Interleukin-12/metabolism , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , Leukocytes/immunology , Leukocytes/metabolism , Male , Probability , Sensitivity and Specificity , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , Term BirthABSTRACT
BACKGROUND: Neonatal susceptibility to bacterial infection is associated with an immature immune system, but the role of different bacterial antigens in specific responses is largely unknown. OBJECTIVE: To evaluate differences in intracellular cytokine response to physiologically relevant bacterial antigens in term and preterm infants as compared with adults. METHODS: Cord blood samples from preterm and term neonates and adult peripheral blood samples were cultured ex vivo with and without whole heat-killed bacteria. Intracellular leukocyte production of interleukin (IL)-6, IL-10, IL-12, and IL-8 responses was assessed by flow cytometry. RESULTS: Monocytes were the primary producers of all mediators. Escherichia coli was the most potent stimulant. Lactobacillus plantarum 299v activated fewer monocytes as compared with E. coli for all responses (p < 0.05), except for IL-12 in term neonates. IL-6 response to Staphylococcus epidermidis was lower in both groups of neonates as compared with adults (p = 0.023 and p = 0.001). IL-8 response to S. epidermidis was lower in term as compared with preterm neonates and adults (p = 0.003). IL-10 response to group B streptococci was lower in term neonates as compared with adults and higher in preterm as compared with term neonates (p = 0.015). CONCLUSIONS: Monocytes from term neonates compared to preterm neonates show a downregulated anti-inflammatory response to specific bacteria. High neonatal response to pathogenic E. coli in the preterm infant could cause uncontrolled inflammatory response, while lower IL-6 response to S. epidermidis in neonates may indicate a basis for vulnerability to S. epidermidis infection.
Subject(s)
Antigens, Bacterial/pharmacology , Cytokines/metabolism , Fetal Blood/cytology , Monocytes/metabolism , Adult , Antigens, Bacterial/immunology , Cells, Cultured , Escherichia coli/immunology , Female , Humans , Infant, Newborn , Infant, Premature , Interleukin-10/metabolism , Interleukin-12/metabolism , Interleukin-6/metabolism , Interleukin-8/metabolism , Lactobacillus plantarum/immunology , Male , Middle Aged , Monocytes/cytology , Monocytes/drug effects , Staphylococcus epidermidis/immunologyABSTRACT
A review of 25,448 admissions was performed to evaluate the progress of neonatal intensive care at Weill Cornell Medical Center since 1978. Patients were identified by a review of admission and discharge data compiled by admitting staff. The following data were collected: birth weight, gestational age, place of birth (inborn versus outborn), discharge date, disposition. Length of stay was computed from these data. Data were organized according to year of admission. Admissions remained relatively constant with time. However the percentage of inborn infants steadily increased. Survival of the smallest infants (<600 g) remained poor, but overall survival of all infants improved over time. Length of stay for infants 1000 to 2000 g fell over time while that of other infants remained constant. These trends reflect changes in obstetric and neonatal practice over time, and include improved methods of antenatal care, neonatal pulmonary care, and nutrition, as well as changes in the distribution of neonatal and high-risk maternal care.
