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

Macrophage Sult2b1 promotes pathological neovascularization in age-related macular degeneration

Disordered immune responses and cholesterol metabolism have been implicated in age-related macular degeneration (AMD), the leading cause of blindness in elderly individuals. SULT2B1, the key enzyme of sterol sulfonation, plays important roles in inflammation and cholesterol metabolism. However, the role and underlying mechanism of SULT2B1 in AMD have not been investigated thus far. Here, we report that SULT2B1 is specifically expressed in macrophages in choroidal neovascularization lesions. Sutl2b1 deficiency significantly reduced leakage areas and inhibited pathological angiogenesis by inhibiting M2 macrophage activation in vivo and in vitro. Mechanistically, loss of Sult2b1 activated LXRs and subsequently increased ABCA1 and ABCG1 (ABCA1/G1)-mediated cholesterol efflux from M2 macrophages. LXR inhibition (GSK2033 treatment) in Sult2b1 -/- macrophages reversed M2 polarization and decreased intracellular cholesterol capacity to promote pathological angiogenesis. In contrast to SULT2B1, STS, an enzyme of sterol desulfonation, protected against choroidal neovascularization development by activating LXR-ABCA1/G1 signalling to block M2 polarization. Collectively, these data reveal a cholesterol metabolism axis related to macrophage polarization in neovascular AMD.

Maternal imprinting and determinants of neonates' immune function in the SEPAGES mother-child cohort

Introduction

Immune function in pregnancy is influenced by host-specific and environmental factors. This may impact fetal immune development, but the link between maternal and neonatal immune function is still poorly characterized. Here, we investigate the relationship between maternal and neonatal immune function, and identify factors affecting the association between maternal and child cytokine secretion.

Methods

In the French prospective cohort SEPAGES, blood samples were obtained from pregnant women (n=322) at gestational week 20 ± 4 and from their child at birth (n=156). Maternal and cord blood cytokine and chemokine (CK) levels were measured at baseline in all subjects and after T cell or dendritic cell activation with phytohemagglutinin or R848 (in total 29 and 27 measures in maternal and cord blood samples, respectively). Associations between environmental, individual factors and CK level were estimated by linear regression modeling. The maternal-cord blood CK relations were assessed by Pearson correlation and regression models.

Results

We observed that pregnant women and neonates displayed specific CK secretion profiles in the innate and adaptive compartments at baseline and upon activation. Activation of T cells in cord blood induced high levels of IL-2, but low levels of IFNγ, IL-13 or IL-10, in comparison to maternal blood samples. Elsewhere, neonatal innate immune responses were characterized by low production of IFNα, while productions of IL-1β, IL-6, IL-8, IL-10 and TNFα were higher than maternal responses. Strong correlations were observed between most CK after activation in maternal and cord blood samples. Strikingly, a statistical association between global mother and child cytokine profiles was evidenced. Correlations were observed between some individual CK of pregnant women and their children, both at baseline (MCP1, RANTES) and after activation with R848 (IL-6, IL-8 and IL-10). We looked for factors which could influence cytokine secretion in maternal or cord blood, and found that leucocyte counts, maternal age, pre-conception BMI, smoking and season were associated with the levels of several CK in mothers or children.

Discussion

Our study reveals in utero immune imprinting influencing immune responses in infants, opening the way to investigate the mechanisms responsible for this imprinting. Whether such influences have long lasting effects on children health warrants further investigation.

T2 Biologics for Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality worldwide. In contrast to other chronic diseases, COPD is increasing in prevalence and is projected to be the third leading cause of death and disability worldwide by 2030. Recent advances in understanding the underlying pathophysiology of COPD has led to the development of novel targeted therapies (biologics and small molecules) that address the underlying pathophysiology of the disease. In severe asthma, biologics targeting type 2 (T2)- mediated immunity have been successful and have changed the treatment paradigm. In contrast, no biologics are currently licensed for the treatment of COPD. Those targeting non-T2 pathways have not demonstrated efficacy and in some cases raised concerns related to safety. With the increasing recognition of the eosinophil and perhaps T2-immunity possibly playing a role in a subgroup of patients with COPD, T2 biologics, specifically anti-IL-5(R), have been tested and demonstrated modest reductions in exacerbation frequency. Potential benefit was related to the baseline blood eosinophil count. These benefits were small compared with asthma. Thus, whether a subgroup of COPD sufferers might respond to anti-IL-5 or other T2-directed biologics remains to be fully addressed and requires further investigation.

Cytokine profiles of umbilical cord blood mononuclear cells upon in vitro stimulation with lipopolysaccharides of different vaginal gram-negative bacteria

Inflammatory immune responses induced by lipopolysaccharides (LPS) of gram-negative bacteria play an important role in the pathogenesis of preterm labor and delivery, and in neonatal disorders. To better characterize LPS-induced inflammatory response, we determined the cytokine profile of umbilical cord blood mononuclear cells (UBMC) stimulated with LPS of seven vaginal gram-negative bacteria commonly found in pregnant women with preterm labor and preterm rupture of membrane. UBMC from ten newborns of healthy volunteer mothers were stimulated with purified LPS of Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus mirabilis, Acinetobacter calcoaceticus, Citrobacter freundii, and Pseudomonas aeruginosa. UBMC supernatants were tested for the presence of secreted pro-inflammatory cytokines (IL-6, IL-1β, TNF), anti-inflammatory cytokine (IL-10), TH₁-type cytokines (IL-12, IFN-γ), and chemokines (IL-8, MIP-1α, MIP-1β, MCP-1) by Luminex technology. The ten cytokines were differentially induced by the LPS variants. LPS of E. coli and E. aerogenes showed the strongest stimulatory activity and P. aeruginosa the lowest. Interestingly, the ability of UBMC to respond to LPS varied greatly among donors, suggesting a strong individual heterogeneity in LPS-triggered inflammatory response.

Developmental psychoneuroendocrine and psychoneuroimmune pathways from childhood adversity to disease

Childhood adversity has been repeatedly and robustly linked to physical and mental illness across the lifespan. Yet, the biological pathways through which this occurs remain unclear. Functioning of the inflammatory arm of the immune system and the hypothalamic-pituitary-adrenal (HPA)-axis are both hypothesized pathways through which childhood adversity leads to disease. This review provides a novel developmental framework for examining the role of adversity type and timing in inflammatory and HPA-axis functioning. In particular, we identify elements of childhood adversity that are salient to the developing organism: physical threat, disrupted caregiving, and unpredictable environmental conditions. We propose that existing, well-characterized animal models may be useful in differentiating the effects of these adversity elements and review both the animal and human literature that supports these ideas. To support these hypotheses, we also provide a detailed description of the development and structure of both the HPA-axis and the inflammatory arm of the immune system, as well as recent methodological advances in their measurement. Recommendations for future basic, developmental, translational, and clinical research are discussed.

In vitro cytokine induction by TLR-activating vaccine adjuvants in human blood varies by age and adjuvant

Most infections occur in early life, prompting development of novel adjuvanted vaccines to protect newborns and infants. Several Toll-like receptor (TLR) agonists (TLRAs) are components of licensed vaccine formulations or are in development as candidate adjuvants. However, the type and magnitude of immune responses to TLRAs may vary with the TLR activated as well as age and geographic location. Most notably, in newborns, as compared to adults, the immune response to TLRAs is polarized with lower Th1 cytokine production and robust Th2 and anti-inflammatory cytokine production. The ontogeny of TLR-mediated cytokine responses in international cohorts has been reported, but no study has compared cytokine responses to TLRAs between U.S. neonates and infants at the age of 6months. Both are critical age groups for the currently pediatric vaccine schedule. In this study, we report quantitative differences in the production of a panel of 14 cytokines and chemokines after in vitro stimulation of newborn cord blood and infant and adult peripheral blood with agonists of TLR4, including monophosphoryl lipid A (MPLA) and glucopyranosyl lipid Adjuvant aqueous formulation (GLA-AF), as well as agonists of TLR7/8 (R848) and TLR9 (CpG). Both TLR4 agonists, MPLA and GLA-AF, induced greater concentrations of Th1 cytokines CXCL10, TNF and Interleukin (IL)-12p70 in infant and adult blood compared to newborn blood. All the tested TLRAs induced greater infant IFN-α2 production compared to newborn and adult blood. In contrast, CpG induced greater IFN-γ, IL-1β, IL-4, IL-12p40, IL-10 and CXCL8 in newborn than in infant and adult blood. Overall, to the extent that these in vitro studies mirror responses in vivo, our study demonstrates distinct age-specific effects of TLRAs that may inform their development as candidate adjuvants for early life vaccines.

Age-dependent changes in pattern recognition receptor and cytokine mRNA expression in children with otitis media with effusion

OBJECTIVE

To investigate age-dependent changes in expression of pattern recognition receptors (PRRs) and cytokines in pediatric OME.

MATERIALS AND METHODS

Ninety five pediatric patients with OME were divided into 4 age groups: 0-2, 2-4, 4-7, and over 7 years. The presence of bacteria, and the levels of expression of mRNAs encoding Toll-like receptor (TLRs), NOD like receptors (NLRs) and cytokines in middle ear fluid were assessed, as were their correlations with age, gender, presence of bacteria and accompanying disease.

RESULTS

Bacteria were detected in 32.6% of patients. The levels of expression of PRR and cytokine mRNAs tended to be lower in children aged 2-4 and 4-7 years. The levels of expression of TLR-2, TLR-9, NOD-1, NOD-2, IL-1, IL-6, and TNF-α mRNAs in effusion fluid were significantly lower in these two groups than in children aged 0-2 and over 7 years (p<0.05 each). The levels of expression of TLR-4, TLR-5, TLR-9, and NOD-1 mRNAs were significantly lower in culture positive than in culture negative patients (p<0.05 each). However, the expression levels of PRR and cytokine mRNAs were unrelated to gender and accompanying disease (p>0.05 each).

CONCLUSIONS

The levels of expression of PRR and cytokine mRNAs differed by age in children with OME.

Microcirculatory changes in term newborns with suspected infection: an observational prospective study

Background. In adults severely disturbed microcirculatory flow can be observed by Orthogonal Polarized Spectral (OPS) imaging techniques during sepsis. Therefore we set out to assess for microcirculatory changes in term newborns with suspected early onset infection using OPS. Methods. OPS images were obtained prospectively from the vascular bed of the ear conch and upper arm of 47 newborns on their 1st, 2nd, and 3rd day of life. OPS sequences were analyzed semiquantitatively offline and blinded to clinical status of the infant. Flow in vessels was classified as continuous or noncontinuous flow and given as proportion of total vessels per image as in the studies in adults. Results. The proportion of vessels with continuous flow was significantly lower in the infants with infection (69% [56–81] versus 90% [87–94] (P = 0.0003)). None of the infants with infection was in shock or severely septic. Conclusion. In term neonates the microcirculatory flow is impaired in a large proportion of vessels even in mild to moderate infection. These changes can be observed at the onset of disease at the external ear, an optimal site for microcirculatory measurements in term infants.

Male gender promotes an increased inflammatory response to lipopolysaccharide in umbilical vein blood

OBJECTIVES

To establish gender-specific differences in maternal and fetal immune response in healthy human fetuses at term.

METHODS

Forty-five women with elective caesarean sections for uncomplicated singleton pregnancies were recruited for two studies. Using a multiplex biomarker immunoassay system, unstimulated maternal and fetal plasma concentrations of interleukin (IL)-1β, IL-1ra, IL-6, IL-8, macrophage inflammatory protein (MIP)-1α, and tumor necrosis factor (TNF)-α were measured from one study population. Lipopolysaccharide (LPS)-stimulated cytokine response was measured in a second study.

RESULTS

There were no significant gender differences in either maternal or fetal unstimulated plasma cytokine concentrations, but concentrations of the proinflammatory cytokines IL-1β and IL-6 were significantly greater in male fetal LPS-stimulated samples than in female fetal samples.

CONCLUSIONS

Blood of male fetuses mounts a larger pro-inflammatory response to lipopolysaccharide (LPS). This heightened response could be a critical pathway in promoting premature rupture of membranes (PPROM) and may be associated with life long differential gender response to infection.

Innate immune deficiency of extremely premature neonates can be reversed by interferon-γ

BACKGROUND

Bacterial sepsis is a major threat in neonates born prematurely, and is associated with elevated morbidity and mortality. Little is known on the innate immune response to bacteria among extremely premature infants.

METHODOLOGY/PRINCIPAL FINDINGS

We compared innate immune functions to bacteria commonly causing sepsis in 21 infants of less than 28 wks of gestational age, 24 infants born between 28 and 32 wks of gestational age, 25 term newborns and 20 healthy adults. Levels of surface expression of innate immune receptors (CD14, TLR2, TLR4, and MD-2) for Gram-positive and Gram-negative bacteria were measured in cord blood leukocytes at the time of birth. The cytokine response to bacteria of those leukocytes as well as plasma-dependent opsonophagocytosis of bacteria by target leukocytes was also measured in the presence or absence of interferon-γ. Leukocytes from extremely premature infants expressed very low levels of receptors important for bacterial recognition. Leukocyte inflammatory responses to bacteria and opsonophagocytic activity of plasma from premature infants were also severely impaired compared to term newborns or adults. These innate immune defects could be corrected when blood from premature infants was incubated ex vivo 12 hrs with interferon-γ.

CONCLUSION/SIGNIFICANCE

Premature infants display markedly impaired innate immune functions, which likely account for their propensity to develop bacterial sepsis during the neonatal period. The fetal innate immune response progressively matures in the last three months in utero. Ex vivo treatment of leukocytes from premature neonates with interferon-γ reversed their innate immune responses deficiency to bacteria. These data represent a promising proof-of-concept to treat premature newborns at the time of delivery with pharmacological agents aimed at maturing innate immune responses in order to prevent neonatal sepsis.

Immune system development during early childhood in tropical Latin America: evidence for the age-dependent down regulation of the innate immune response

The immune response that develops in early childhood underlies the development of inflammatory diseases such as asthma and there are few data from tropical Latin America (LA). This study investigated the effects of age on the development of immunity during the first 5 years of life by comparing innate and adaptive immune responses in Ecuadorian children aged 6–9 months, 22–26 months, and 48–60 months. Percentages of naïve CD4+ T cells declined with age while those of memory CD4⁺ and CD8⁺ T cells increased indicating active development of the immune system throughout the first five years. Young infants had greater innate immune responses to TLR agonists compared to older children while regulatory responses including SEB-induced IL-10 and percentages of FoxP3⁺ T-regulatory cells decreased with age. Enhanced innate immunity in early life may be important for host defense against pathogens but may increase the risk of immunopathology.

Profound lack of interleukin (IL)-12/IL-23p40 in neonates born early in gestation is associated with an increased risk of sepsis

BACKGROUND

Infants born prematurely are highly vulnerable to infections and also exhibit a high susceptibility to organ damage due to inflammation.

METHODS

To investigate homeostatic immune control early in life, we used advanced multiparameter flow cytometry to compare responses to multiple Toll-like receptor (TLR) ligands in single cells and mononuclear cell populations in term neonates versus preterm neonates born before 29 weeks of gestation.

RESULTS

Preterm neonates had globally attenuated TLR-stimulated interleukin (IL)-6, interferon-α, and, to a lesser extent, tumor necrosis factor-α responses but demonstrated relative preservation of anti-inflammatory IL-10 responses in monocytes and dendritic cell subtypes. Remarkably, preterm neonates were also profoundly deficient in the common IL-12 and IL-23 cytokines' p40 subunit, which is critical for immunity against a wide variety of microbial pathogens in mice. Consistent with the increased susceptibility to infections resulting from the lack of IL-12/IL-23 in human newborns, significantly lower serum p40 concentrations were observed at birth in infants who developed early-onset sepsis.

CONCLUSION

To our knowledge, this study is the first detailed analysis of multiple TLR function in neonates born extremely premature. Although attenuation of proinflammatory pathways may protect against tissue-damaging immunity early in life, this previously unrecognized p40 immune deficiency appears to result in considerably increased susceptibility to infection in human preterm newborns.

Distinct roles of TLR4 and CD14 in LPS-induced inflammatory responses of neonates

During infections, pathogens bind to toll-like receptor (TLR)4 and CD14 receptors and induce cytokine release, leading to inflammation. Here, we investigated TLR4 and CD14 expression on peripheral blood leukocytes (PBLs) and their roles in lipopolysaccharide (LPS)-induced cytokine and chemokine release. Full-term and preterm neonates and adults were studied. PBLs were pretreated with anti-TLR4- and anti-CD14-blocking antibodies and stimulated with LPS. Cytokine and chemokine levels were measured in supernatants. TLR4, CD14 expression, and LPS-induced CXCL8 release were higher in neonates, possibly contributing to aberrant inflammation. TLR4 blockade resulted in approximately 3-fold greater suppression of LPS-induced CXCL8 release in preterm neonates (38%) than in adults (14%). CD14 blockade (approximately 80%) in neonates induced approximately 3-fold greater inhibition of CXCL8 release, compared with anti-TLR4 (approximately 30%). Anti-TLR4 partly (50-60%) inhibited IL-10 and TNF-alpha, whereas anti-CD14 completely suppressed their release. Our findings reveal that neonates depend more on TLR4 for CXCL8 release. Furthermore, neonatal LPS-induced CXCL8 release, apart from TLR4/CD14-mediated signaling, is regulated by LPS interactions with other TLRs and/or immune receptors. IL-10 and TNF-alpha release depends on LPS binding not only to CD14/TLR4 but also to CD14 associated with another TLR. Our findings reveal the contribution of TLR4 and CD14 in neonatal cytokine and chemokine release and could aid in design of antagonists to prevent harmful inflammation.

Labour increases the surface expression of two Toll-like receptors in the cord blood monocytes of healthy term newborns

AIM

Mode of delivery may influence the innate immune system in newborns. We investigated the effect of maternal labour on the expression of two Toll-like receptors, TLR2 and TLR4, in monocytes obtained from healthy full-term newborns.

METHODS

Monocytes were obtained from cord blood of 48 newborns that have been vaginally delivered (VD) and 14 newborns delivered by elective caesarean section (CS) without labour. Peripheral blood was also obtained from 17 healthy adults. Surface expression of TLR2 and TLR4 in the monocytes was measured by antihuman TLR2 or TLR4 monoclonal antibody and immunofluorescence flow cytometry. TLR2 and TLR4 mRNA levels were evaluated by real-time PCR.

RESULTS

CS newborns had a significantly lower level of TLR2 and TLR4 surface expression on monocytes than VD newborns. No significant difference was found between the surface expression of VD newborns and healthy adults. TLR2 and TLR4 mRNA levels in monocytes did not vary among the three study groups.

CONCLUSION

Labour may up-regulate TLR2 and TLR4 on the cord blood monocytes of newborns at the protein level. Since TLRs are an important part of the innate immune system, our findings suggest that labour may be immunologically beneficial to normal newborns.

Cytokine expression in response to bacterial antigens in preterm and term infant cord blood monocytes

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.

Gene expression profiles of adult peripheral and cord blood mononuclear cells altered by lipopolysaccharide

BACKGROUND

Neonatal Gram-negative sepsis is often characterized by a fulminant clinical course, compared to adults, resulting in higher morbidity and mortality. Genome-wide gene expression analysis can provide insights into the molecular alterations in sepsis.

OBJECTIVES

To evaluate in vitro activation of the neonatal and adult immune system, gene expression patterns were compared in mononuclear cells from cord (CBMNC) and adult peripheral blood (APBMNC).

METHODS

To better understand the influence of early molecular signals on the effects of sepsis, Affymetrix gene profiling (8,475 genes) was done on RNA isolated from CBMNC and APBMNC without and after incubation with 100 ng/ml lipopolysaccharide (LPS).

RESULTS

We demonstrated significant alterations in the expression of 108 CBMNC and APBMNC genes compared with basal levels, 188 significant changes in CBMNC and 97 in APBMNC, including cytokines, chemokines and immunoregulatory genes. Furthermore, we found 5 genes showing a significant interaction effect between cell type and LPS stimulation, including tumor necrosis factor receptor superfamily, member 6 (FAS), absent in melanoma 2, malic enzyme 1, hemoglobin epsilon 1, and trans-prenyltransferase.

CONCLUSIONS

These results provide further support for a marked difference in the pathogenesis of neonatal and adult sepsis and may stimulate additional studies to investigate some of the altered genes as potential new targets for diagnostic tools and therapeutic strategies.

Postnatal development of monocyte cytokine responses to bacterial lipopolysaccharide

Early childhood is a period of heightened susceptibility to infection due to immaturity of the immune system, and the nature of these developmental deficiencies is only partially understood. In this study, we focused on the ontogeny of the innate immune system by investigating the capacity of mononuclear cells to secrete a wide spectrum of inflammatory cytokines in response to interferon (IFN)-gamma priming and lipopolysaccharide (LPS) stimulation, namely IL-6, IL-10, IL-12, IL-18, IL-23, tumor necrosis factor (TNF)-alpha, and myxovirus resistance protein A, induced by type-I IFN, at several time points between birth (cord blood) and adulthood. Competence to produce all these cytokines followed a similar developmental pattern, with slow postnatal up-regulation from the response observed in cord blood. Unexpectedly, IL-6, IL-10, TNF-alpha, and IFN-gamma showed slow postnatal up-regulation but also elevated cord blood responses equal to or greater than the adult level. This was transient and not observed at 2 mo of age, and was not related to predelivery stress of the newborns. Variations in Toll-like receptor (TLR)4 function may account for these age related differences in cytokine responses, as TLR4 expression on neonatal monocytes post LPS stimulation was elevated and sustained relative to infants and adults.

Levels of pro-inflammatory cytokines produced from cord blood in-vitro are pathogen dependent and increased in comparison to adult controls

BACKGROUND

Overproduction of pro-inflammatory cytokines may play a role in increased morbidity and mortality from neonatal sepsis. Objective of this study was to compare secretion of pro-inflammatory cytokines by the cord blood cells of healthy term neonates to the venous blood cells of healthy adults in vitro after stimulation with common neonatal pathogens.

METHOD

Blood samples were cultured in the presence of heat-killed group B beta-hemolytic streptococci (GBS), Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epi). Concentrations of secreted cytokines (interleukine-6, IL-6, tumor necrosis factor-alpha, TNF-alpha, interleukine-1 beta, IL-1beta and interleukine-8, IL-8) were measured after 0, 1, 2 and 4 h of incubation using chemiluminescent immunometric automated assay.

RESULTS

Blood samples from 22 neonates and 16 adults were compared. After stimulation by GBS and E. coli, cord blood cells secreted significantly higher levels of IL-6 and IL-8 than blood cells of healthy adults. In cord blood, E. coli induced secretion of higher concentration of IL-6, TNF-alpha, IL-1beta and IL-8 than S. epi, and more IL-6 than GBS; GBS induced more IL-1beta than S.epi.

CONCLUSIONS

Response of cord blood to microbial activators is different from that of adult controls. Each isolate of heat-killed bacteria induced different amount of pro-inflammatory cytokines in vitro. This may represent a useful in vitro virulence test.

Selective developmental defects of cord blood antigen-presenting cell subsets

Defective antigen-presenting cell (APC) function has been hypothesized to contribute to increased infection susceptibility in newborns. We used multiparameter flow cytometry to characterize APC subsets in adult peripheral blood (APB) and cord blood (CB). APB had a higher proportion of CD11c+ dendritic cells (DC), whereas CB mainly contained CD123+ DC. APB was enriched in CD16+CD11c+ DC subset, whereas CD34+CD11c-CD123lo cells were prominent in CB. Lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-alpha production was dampened in myeloid DC and monocytes from CB, whereas IL-1alpha production was not different. The reduction in TNF-alpha response did not appear to result from reduced surface detection of LPS, because CD14, toll-like receptor (TLR)-4 and TLR-2 levels were not reduced in CB APC compared with APB cells. Also, there was no correlation between TLR-2 or TLR-4 levels and TNF-alpha production in myeloid DC and monocytes. CB monocytes had lower surface HLA-DR immediately ex vivo. Both APB and CB monocytes upregulated HLA-DR after incubation, but an additional LPS-induced increase in HLA-DR was suggested only in APB monocytes. APB monocytes also showed a greater LPS-induced increase in CD40 expression. Together, our data show significant, selective differences in circulating APC between neonates and adults.

The influence of the mode of delivery on circulating cytokine concentrations in the perinatal period

BACKGROUND

Cytokines play an important role during labor and full- or preterm delivery. They influence physical immunity of the fetus-neonate and express a leading role in the perinatal period, being present in maternal and fetal tissues.

AIM

To investigate whether cytokine concentrations in the mother, fetus and neonate depend on the labor and the mode of the delivery.

STUDY DESIGN

Prospective study.

SUBJECTS

Seventy-eight healthy, non-smoking parturients (mean age 28+/-4, range 21-39 years, delivering vaginally: n=52 or by elective cesarean section: n=26) and their single, healthy, appropriate for gestational age, full-term neonates.

OUTCOME MEASURES

We correlated determined circulating levels of IL-2, sIL-2R, IL-4, sIL-4R, IL-6, sIL-6R, IL-1beta, IL-8, IFN-gamma, TNF-alpha, sTNF RI, sTNF RII and RANTES in the mothers before delivery (MS), the fetuses (UC) and the neonates in days 1 (N1) and 4 (N4) of life, with the mode of delivery.

RESULTS

sIL-2R in N1 and N4, sIL-4R in MS, IL-6 in MS and UC, IL-1beta in MS, UC and N1, IFN-gamma in MS and UC, TNF-alpha in UC, N1 and N4, sTNF RI in UC were significantly higher in cases of vaginal delivery than in cases of elective cesarean section (p ranging from 0.0005 to 0.05).

CONCLUSIONS

Vaginal delivery promotes the production of various cytokines and their receptors, which are implicated in neonatal immunity.

Lipopolysaccharide binding protein in preterm infants

OBJECTIVE

To assess serum concentrations of lipopolysaccharide binding protein (LBP) in preterm infants with neonatal bacterial infection (NBI).

METHODS

Blood samples were analysed of 57 preterm (28(+1) to 36(+6), median 33(+2) weeks gestation) and 17 term infants admitted to the neonatal intensive care unit within the first 72 hours of life with suspicion of NBI. Samples were obtained at first suspicion of sepsis and after 12 and 24 hours. Diagnosis of NBI was confirmed by raised concentrations of C reactive protein and/or interleukin 6. The influence of gestational age and labour was analysed.

RESULTS

Maximum LBP concentrations in infants with NBI were greatly increased compared with infants without NBI (13.0-46.0 microg/ml (median 20.0 microg/ml) v 0.6-17.4 microg/ml (median 4.2 microg/ml)). LBP concentrations in infected infants were not yet significantly raised when NBI was first suspected. The LBP concentrations of preterm infants were comparable to those of term infants. Regression analysis revealed no significant effect of labour or gestational age on LBP.

CONCLUSIONS

Raised LBP concentrations indicate NBI in preterm and term infants. Preterm infants of > 28 weeks gestation seem to be capable of producing LBP as efficiently as term infants. Neonatal LBP concentrations are not influenced by labour. LBP may be a useful diagnostic marker of NBI in preterm infants.

Cytokine induction in human cord blood lymphocytes after pulsing with UV-inactivated influenza viruses

Mitogenic activity of UV-inactivated influenza viruses in cord blood lymphocytes (CBL), as measured by cytokine release, was investigated. Using prototype viruses of subtype H3N2 (A/Aichi/68), H2N2 (A/Japan/57), and H1N1 (A/Puerto Rico/34) for influenza A virus, and B/Lee/40 for influenza B virus, the results indicated that both Th1 and Th2 cytokines were induced. Stimulation indices were significantly higher for IFNgamma, IL-4 and IL-10 by influenza A viruses than by influenza B virus. Stimulation indices for IL-2 and IL-6 were lower, as these two cytokines were spontaneously released by cord blood lymphocytes in culture. Alignment of the amino acid sequences of the HA for the viruses used in this study indicated that influenza B virus lacked sequence homology to the antigenic sites identified for influenza A virus. Therefore, the antigenic sites may play a role in the mitogenic property, and cord blood lymphocytes could provide a system to compare this property for clinical isolates of influenza virus.

Modification of cord blood IL-6 production with IgM enriched human immunoglobulin in term and preterm infants

Pro-inflammatory cytokines contribute significantly to the morbidity of premature infants. IL-6 and IL-8 are involved in the pathogenesis of pulmonary and cerebral tissue injury. The effect of human immunoglobulin preparations on cytokine production in preterm infants has not been studied. We investigated the influence of immunoglobulin on LPS stimulated IL-6 and IL-8 production in cord blood of healthy preterm neonates. Ten non-infected preterm infants delivered by cesarean section and 5 healthy term neonates were included. In the preterm infants, significant IL-6 production was observed in the absence of immunoglobulin after 4 h [median 113 (39-725) pg/ml], 8 h [375 (234-1795) pg/ml] and 12 h [360 (248-2765) pg/ml] of LPS incubation. IL-6 concentrations were significantly lower after incubation with LPS+immunoglobulin after 4 h [median 38 (5-568) pg/ml; p=0.005], 8 h [178 (10-1830) pg/ml; p=0.001] and 12 h [182 (29-2530) pg/ml; p=0.002]. Cultures from term infants produced IL-6 levels approx. 4 times of those from premature infants unaffected by immunoglobulin. IL-8 production also correlated to gestational age and was not affected by immunoglobulin in both groups. Human immunoglobulin preparation may modify IL-6 production in cord blood cultures from premature infants.