Neonatal interleukin-1 beta, interleukin-6, and tumor necrosis factor: cord blood levels and cellular production

Placental clearance not synthesis tempers exaggerated pro-inflammatory cytokine response in neonates exposed to chorioamnionitis

BACKGROUND

The source and clearance of cytokines in the fetal circulation in term pregnancies complicated by chorioamnionitis remains unclear as are the contributions of placental transport, synthesis, and clearance. The objectives of the study were to determine (1) fetal and/or placental contributions to synthesis and/or clearance of inflammatory and anti-inflammatory cytokines in term pregnancies complicated by chorioamnionitis and (2) whether this differs in pregnancies further complicated by fetal hypoxia.

METHODS

Prospective cohort study of pregnancies >37 weeks gestational age that included: Group 1, uncomplicated cesarean delivery without labor (n = 20); Group 2, uncomplicated vaginal delivery (n = 30); Group 3, pregnancies complicated by chorioamnionitis (n = 10); Group 4, complicated by chorioamnionitis + fetal hypoxia (n = 10). Umbilical arterial (UmA) and venous (UmV) blood were assayed for IL-1β, IL-2, IL-6, IL-8, TNFα, and IL-10.

RESULTS

IL-6 and IL-8 were below assay detection in UmA and UmV blood in Group 1 and increased in Group 2 (P < 0.01), UmA»UmV (P < 0.01). Their concentrations increased further in Groups 3 and 4 (P = 0.003), UmA»UmV. Placental clearance was concentration dependent that approaches saturation in the presence of chorioamnionitis.

CONCLUSIONS

Marked increases in fetal synthesis of IL-6 and IL-8 occur in chorioamnionitis. Synthesis increase further when complicated by fetal hypoxia. Cytokine removal occurs via placental concentration-dependent mechanisms, potentially contributing to adverse fetal effects.

IMPACT

The source and role of the placenta in synthesis and/or clearance of inflammatory mediators in term pregnancies complicated by clinical chorioamnionitis are unclear; however, conventional wisdom suggests the placenta is their source. This is the first study demonstrating that circulating concentrations of fetal IL-6 and IL-8 in clinical chorioamnionitis ± birth asphyxia in term pregnancies are of fetal origin. Circulating fetal inflammatory cytokines are cleared by concentration-dependent placental mechanisms that are nearly saturated in chorioamnionitis ± fetal hypoxia. These observations provide additional insight into understanding the fetal immune response in term pregnancies complicated by clinical chorioamnionitis.

Delivery-Associated Changes in the Levels of Inflammatory Molecules in Newborns

Inflammation is considered a fundamental process accompanying physiological human birth, also playing a role in perinatal pathologies. The goal of the study was to assess the concentrations of inflammatory molecules with respect to the mode of delivery and dynamics of inflammatory molecules in neonatal samples in the first 48-72 hours of life. The concentrations of inflammatory cytokines were measured using the Luminex®xMAP multi-analyte profiling platform in cord blood and peripheral neonatal blood. Study groups included newborns delivered spontaneously (spontaneous group) and via elective caesarean section (elective group). Cord blood concentrations of interleukin 6 (IL-6) and procalcitonin were significantly higher (P < 0.0001) in the spontaneous group compared to the elective group. Neonatal blood concentrations of tumour necrosis factor (TNF) from the elective group were significantly higher com-pared to the spontaneous group (P = 0.0077). The concentrations of procalcitonin and TNF significantly increased within the first 48 to 72 hours following either mode of delivery. IL-6 and IL-18 were significantly higher in neonatal compared to umbilical cord blood in the elective group only, while the increase in the spontaneous group did not reach statistical significance. The concentrations of IL-1α, IL-1β, IL-17A and IL-22 did not show significant differen-ces between the spontaneous and elective groups as well as between umbilical cord and neonatal blood. Our findings show physiological differences in the levels of inflammatory molecules following spontaneous vaginal delivery and elective caesarean section. The results can be used as baseline values for the research of various pathologies in newborns.

Anti-Inflammatory Therapies for Treatment of Inflammation-Related Preterm Brain Injury

Despite the prevalence of preterm brain injury, there are no established neuroprotective strategies to prevent or alleviate mild-to-moderate inflammation-related brain injury. Perinatal infection and inflammation have been shown to trigger acute neuroinflammation, including proinflammatory cytokine release and gliosis, which are associated with acute and chronic disturbances in brain cell survival and maturation. These findings suggest the hypothesis that the inhibition of peripheral immune responses following infection or nonspecific inflammation may be a therapeutic strategy to reduce the associated brain injury and neurobehavioral deficits. This review provides an overview of the neonatal immunity, neuroinflammation, and mechanisms of inflammation-related brain injury in preterm infants and explores the safety and efficacy of anti-inflammatory agents as potentially neurotherapeutics.

Neonatal Sepsis

Neonatal sepsis is associated with severe morbidity and mortality in the neonatal period. Clinical manifestations range from subclinical infection to severe local or systemic infection. Neonatal sepsis is divided into three groups as early-onset neonatal sepsis, late-onset neonatal sepsis and very late-onset neonatal sepsis according to the time of the onset. It was observed that the incidence of early-onset neonatal sepsis decreased with intrapartum antibiotic treatment. However, the incidence of late-onset neonatal sepsis has increased with the increase in the survival rate of preterm and very low weight babies. The source of the causative pathogen may be acquisition from the intrauterine origin but may also acquisition from maternal flora, hospital or community. Prematurity, low birth weight, chorioamnionitis, premature prolonged rupture of membranes, resuscitation, low APGAR score, inability to breastfeed, prolonged hospital stay and invasive procedures are among the risk factors. This article reviews current information on the definition, classification, epidemiology, risk factors, pathogenesis, clinical symptoms, diagnostic methods and treatment of neonatal sepsis.

Nerve cells developmental processes and the dynamic role of cytokine signaling

The stunning diversity of neurons and glial cells makes possible the higher functions of the central nervous system (CNS), allowing the organism to sense, interpret and respond appropriately to the external environment. This cellular diversity derives from a single primary progenitor cell type initiating lineage leading to the formation of both differentiated neurons and glial cells. The processes governing the differentiation of the progenitor pool of cells into mature nerve cells will be here briefly reviewed. They involve morphological transformations, specialized modes of cell division, migration, and controlled cell death, and are regulated through cell-cell interactions and cues provided by the extracellular matrix, as well as by humoral factors from the cerebrospinal fluid and the blood system. In this respect, a quite large body of studies have been focused on cytokines, proteins representing the main signaling network that coordinates immune defense and the maintenance of homeostasis. At the same time, they are deeply involved in CNS development as regulatory factors. This dual role in the nervous system appears of particular relevance for CNS pathology, since cytokine dysregulation (occurring as a consequence of maternal infection, exposure to environmental factors or prenatal hypoxia) can profoundly impact on neurodevelopment and likely influence the response of the adult tissue during neuroinflammatory events.

Mefenamic Acid Attenuates Chronic Alcohol Induced Cognitive Impairment in Zebrafish: Possible Role of Cholinergic Pathway

Based on the scientific evidence supporting the neuroinflammatory response contributes the cognitive impairment associated with chronic alcoholism and the neuroprotective actions of mefenamic acid with reversal of memory loss and brain inflammation in mice, this study was designed to evaluate the effect of mefenamic acid against chronic alcohol induced cognitive impairment in zebrafish model. Zebrafish were grouped and subjected to normal behavioral analysis in light-dark chamber for 10 days. The preference to dark compartment was noted in zebrafish. Zebrafish were grouped and exposed to escalating doses of alcohol for 28 days with and without mefenamic acid exposure (100 and 200 µg/L) and subjected to a fear conditioning passive avoidance task from day 13 of 28. The cognitive evaluation was performed for 10 days and the brain tissue was isolated to estimate acetylcholinesterase activity. In cognitive evaluation study, the normal zebrafish retained the memory of the learned task and avoided the dark. The alcohol exposed zebrafish showed impairment in retaining the memory of learned task. Mefenamic acid exposed zebrafish showed a significant protection against cognitive impairment caused by alcohol and retained the memory of learned task with a significant decrease in AChE activity in brain homogenate compared to alcohol exposed zebrafish. The results of this study suggest that the memory enhancing activity of mefenamic acid might be due to activation of cholinergic transmission that has protected neuroinflammatory and neurodegenerative conditions caused by alcohol.

C reactive protein in healthy term newborns during the first 48 hours of life

BACKGROUND

Early-onset neonatal sepsis (EOS) is a serious and potentially life-threatening disease in newborns. C reactive protein (CRP) is the most used laboratory biomarker for the detection of EOS. Little is known about normal reference values of CRP during the perinatal period as several factors are able to influence it.

OBJECTIVES

To identify an appropriate range of CRP values in healthy term newborns during the first 48 hours of life.

DESIGN

CRP determination was performed in 859 term newborns at 12, 24 and 48 hours of life. Mode of delivery, maternal vaginal culture results, intrapartum antimicrobial prophylaxis (IAP) and other perinatal variables were recorded.

RESULTS

CRP mean values were significantly higher at 48 hours (4.10 mg/L) than at both 24 (2.30 mg/L) and 12 hours of life (0.80 mg/L). CRP levels were affected by a number of perinatal proinflammatory variables. In particular, CRP mean values were significantly higher in babies born by vaginal delivery (3.80 mg/L) and emergency caesarean section (3.60 mg/L) than in babies born by elective caesarean section (2.10 mg/L). Completed course of IAP led to lower CRP mean values (2.90 mg/L) than IAP not completed (3.80 mg/L) or not performed (4.70 mg/L).

CONCLUSIONS

Postnatal age and mode of delivery significantly influence CRP values. Reliable reference values are crucial in order to obtain an adequate diagnostic accuracy.

Targets for Drug Therapy for Autism Spectrum Disorder: Challenges and Future Directions

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by persistent deficits in social communication and interaction and restricted, repetitive patterns of behavior, interests, and activities. Various factors are involved in the etiopathogenesis of ASD, including genetic factors, environmental toxins and stressors, impaired immune responses, mitochondrial dysfunction, and neuroinflammation. The heterogeneity in the phenotype among ASD patients and the complex etiology of the condition have long impeded the advancement of the development of pharmacological therapies. In the recent years, the integration of findings from mouse models to human genetics resulted in considerable progress toward the understanding of ASD pathophysiology. Currently, strategies to treat core symptoms of ASD are directed to correct synaptic dysfunctions, abnormalities in central oxytocin, vasopressin, and serotonin neurotransmission, and neuroinflammation. Here, we present a survey of the studies that have suggested molecular targets for drug development for ASD and the state-of-the-art of medicinal chemistry efforts in related areas.

A comparison of blood and cerebrospinal fluid cytokines (IL-1β, IL-6, IL-18, TNF-α) in neonates with perinatal hypoxia

Perinatal hypoxia-ischemia is a specific and important pathological event in neonatal care practice. The data on relationship between the concentrations of cytokines in blood and cerebrospinal fluid (CSF) and perinatal brain injury are scarce. The aim of this study is to evaluate changes in interleukin (IL-1β, IL-6, and IL-18) and tumor necrosis factor alpha (TNF-α) levels in newborns with perinatal hypoxia (PNH). CSF and serum samples of 35 term and near-term (35-40 weeks) newborns with PNH, at the age of 3-96 hours, were analyzed using enzyme-linked immunosorbent assay. Control group consisted of 25 non-asphyxic/non-hypoxic infants of the same age sampled for clinically suspected perinatal meningitis, but proven negative and healthy otherwise. The cytokine values in CSF and serum samples were determined in relation to initial hypoxic-ischemic encephalopathy (HIE) staged according the Sarnat/Sarnat method, and compared with neurological outcome at 12 months of age estimated using Amiel-Tison procedure. The concentrations of IL-6 and TNF-α in serum of PNH patients were significantly higher compared to control group (p = 0.0407 and p = 0.023, respectively). No significant difference between average values of cytokines in relation to the stage of HIE was observed. Significantly higher levels of IL-6 and IL-18 corresponded to a mildly abnormal neurological outcome, while higher levels of IL-6 and TNF-α corresponded to a severely abnormal neurological outcome, at 12 months of age. Elevated serum levels of IL-6 and TNF-α better corresponded with hypoxia/ischemia compared to CSF values, within 96 hours of birth. Also, higher serum levels of IL-6, TNF-α, and IL-18 corresponded better with abnormal neurological outcome at 12 months of age, compared to CSF values.

Beyond infection - Maternal immune activation by environmental factors, microglial development, and relevance for autism spectrum disorders

Immune molecules such as cytokines and chemokines and the cells that produce them within the brain, notably microglia, are critical for normal brain development. This recognition has in recent years led to the working hypothesis that inflammatory events during pregnancy, e.g. in response to infection, may disrupt the normal expression of immune molecules during critical stages of neural development and thereby contribute to the risk for neurodevelopmental disorders such as autism spectrum disorder (ASD). This hypothesis has in large part been shepherded by the work of Dr. Paul Patterson and colleagues, which has elegantly demonstrated that a single viral infection or injection of a viral mimetic to pregnant mice significantly and persistently impacts offspring immune and nervous system function, changes that underlie ASD-like behavioral dysfunction including social and communication deficits. Subsequent studies by many labs - in humans and in non-human animal models - have supported the hypothesis that ongoing disrupted immune molecule expression and/or neuroinflammation contributes to at least a significant subset of ASD. The heterogeneous clinical and biological phenotypes observed in ASD strongly suggest that in genetically susceptible individuals, environmental risk factors combine or synergize to create a tipping or threshold point for dysfunction. Importantly, animal studies showing a link between maternal immune activation (MIA) and ASD-like outcomes in offspring involve different species and diverse environmental factors associated with ASD in humans, beyond infection, including toxin exposures, maternal stress, and maternal obesity, all of which impact inflammatory or immune pathways. The goal of this review is to highlight the broader implications of Dr. Patterson's work for the field of autism, with a focus on the impact that MIA by diverse environmental factors has on fetal brain development, immune system development, and the pathophysiology of ASD.

Potential biomarkers for effective screening of neonatal sepsis infections: An overview

Neonatal sepsis, a clinical disorder developed by bacterial blood stream infections (BSI) in neonates, is one of the serious global public health problems that must be addressed. More than one million of the estimated global newborn deaths per year are occurred due to severe infections. The genesis of the infection is divided into early-onset sepsis (EOS) and late-onset sepsis (LOS) of the disease. The clinical complications of neonatal sepsis may be associated with bronchopulmonary dysplasia, ductus arteriosus and necrotizing enterocolitis. The clinical diagnosis and treatment of neonatal sepsis is highly complicated. Over the past few years distinct biomarkers have been identified. Most widely used biomarkers are C-reactive protein, Procalcitonin (PCT) and Serum amyloid A (SAA). Until recently, many potential biomarkers including Cell Surface antigens and Bacterial surface antigens and genetic biomarkers are being investigated. Protein biomarkers, cytokines and chemokines are getting much interest for identification of neonatal sepsis infection.

Microglial Priming and Alzheimer's Disease: A Possible Role for (Early) Immune Challenges and Epigenetics?

Neuroinflammation is thought to contribute to Alzheimer's disease (AD) pathogenesis that is, to a large extent, mediated by microglia. Given the tight interaction between the immune system and the brain, peripheral immune challenges can profoundly affect brain function. Indeed, both preclinical and clinical studies have indicated that an aberrant inflammatory response can elicit behavioral impairments and cognitive deficits, especially when the brain is in a vulnerable state, e.g., during early development, as a result of aging, or under disease conditions like AD. However, how exactly peripheral immune challenges affect brain function and whether this is mediated by aberrant microglial functioning remains largely elusive. In this review, we hypothesize that: (1) systemic immune challenges occurring during vulnerable periods of life can increase the propensity to induce later cognitive dysfunction and accelerate AD pathology; and (2) that "priming" of microglial cells is instrumental in mediating this vulnerability. We highlight how microglia can be primed by both neonatal infections as well as by aging, two periods of life during which microglial activity is known to be specifically upregulated. Lasting changes in (the ratios of) specific microglial phenotypes can result in an exaggerated pro-inflammatory cytokine response to subsequent inflammatory challenges. While the resulting changes in brain function are initially transient, a continued and/or excess release of such pro-inflammatory cytokines can activate various downstream cellular cascades known to be relevant for AD. Finally, we discuss microglial priming and the aberrant microglial response as potential target for treatment strategies for AD.

Clinical chorioamnionitis at term VI: acute chorioamnionitis and funisitis according to the presence or absence of microorganisms and inflammation in the amniotic cavity

OBJECTIVE

Neonates born to mothers with clinical chorioamnionitis at term are at an increased risk of infection. Acute subchorionitis, chorioamnionitis, and funisitis are considered placental histologic features consistent with acute inflammation according to the Society for Pediatric Pathology. The objectives of this study were to examine the performance of placental histologic features in the identification of: 1) microbial-associated intra-amniotic inflammation (intra-amniotic infection); and 2) fetal inflammatory response syndrome (FIRS).

METHODS

This retrospective cohort study included women with the diagnosis of clinical chorioamnionitis at term (n=45), who underwent an amniocentesis to determine: 1) the presence of microorganisms using both cultivation and molecular biologic techniques [polymerase chain reaction (PCR) with broad range primers]; and 2) interleukin (IL)-6 concentrations by enzyme-linked immunosorbent assay (ELISA). The diagnostic performance (sensitivity, specificity, accuracy, and likelihood ratios) of placental histologic features consistent with acute inflammation was determined for the identification of microbial-associated intra-amniotic inflammation and FIRS.

RESULTS

1) The presence of acute histologic chorioamnionitis and funisitis was associated with the presence of proven intra-amniotic infection assessed by amniotic fluid analysis; 2) funisitis was also associated with the presence of FIRS; 3) the negative predictive value of acute funisitis ≥stage 2 for the identification of neonates born to mothers with intra-amniotic infection was <50%, and therefore, suboptimal to exclude fetal exposure to bacteria in the amniotic cavity; and 4) acute funisitis ≥stage 2 had a negative predictive value of 86.8% for the identification of FIRS in a population with a prevalence of 20%.

CONCLUSION

Acute histologic chorioamnionitis and funisitis are associated with intra-amniotic infection and the presence of FIRS. However, current pathologic methods have limitations in the identification of the fetus exposed to microorganisms present in the amniotic cavity. Further studies are thus required to determine whether molecular markers can enhance the performance of placental pathology in the identification of neonates at risk for neonatal sepsis.

Clinical chorioamnionitis at term V: umbilical cord plasma cytokine profile in the context of a systemic maternal inflammatory response

OBJECTIVE

Microbial invasion of the fetus due to intra-amniotic infection can lead to a systemic inflammatory response characterized by elevated concentrations of cytokines in the umbilical cord plasma/serum. Clinical chorioamnionitis represents the maternal syndrome often associated with intra-amniotic infection, although other causes of this syndrome have been recently described. The objective of this study was to characterize the umbilical cord plasma cytokine profile in neonates born to mothers with clinical chorioamnionitis at term, according to the presence or absence of bacteria and/or intra-amniotic inflammation.

MATERIALS AND METHODS

A cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=38; cases) and those with spontaneous term labor without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) and amniotic fluid interleukin (IL)-6 concentration into three groups: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. A fetal inflammatory response syndrome (FIRS) was defined as an umbilical cord plasma IL-6 concentration >11 pg/mL. The umbilical cord plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) Neonates born to mothers with clinical chorioamnionitis at term (considered in toto) had significantly higher median umbilical cord plasma concentrations of IL-6, IL-12p70, IL-16, IL-13, IL-4, IL-10 and IL-8, but significantly lower interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF)-α concentrations than neonates born to mothers with spontaneous term labor without clinical chorioamnionitis; 2) neonates born to mothers with clinical chorioamnionitis at term but without intra-amniotic inflammation had higher concentrations of IL-6, IL-12p70, IL-13, IL-4, IL-5, and IL-8, but lower IFN-γ, than neonates not exposed to clinical chorioamnionitis, suggesting that maternal fever in the absence of intra-amniotic inflammation leads to a change in the fetal cytokine network; 3) there were significant, positive correlations between maternal and umbilical cord plasma IL-6 and IL-8 concentrations (IL-6: Spearman correlation=0.53; P<0.001; IL-8: Spearman correlation=0.42; P<0.001), consistent with placental transfer of cytokines; 4) an elevated fetal plasma IL-6 (>11 pg/mL), the diagnostic criterion for FIRS, was present in 21% of cases (8/38), and all these neonates were born to mothers with proven intra-amniotic infection; and 5) FIRS was associated with a high concentration of umbilical cord plasma IL-8, IL-10 and monocyte chemoattractant protein (MCP)-1.

CONCLUSIONS

Neonates born to mothers with clinical chorioamnionitis at term had higher concentrations of umbilical cord plasma cytokines than those born to mothers without clinical chorioamnionitis. Even neonates exposed to clinical chorioamnionitis but not to intra-amniotic inflammation had elevated concentrations of multiple cytokines, suggesting that intrapartum fever alters the fetal immune response.

Neonatal infections in Saudi Arabia: Association with cytokine gene polymorphisms

In recent years, many studies have reported potential associations between cytokine gene polymorphisms and the development, course, and outcome of sepsis, often with apparently conflicting results. The objective of this study was to investigate single nucleotide polymorphism (SNP) in the interleukin (IL)-1β –31 T/C, IL-6 –174 G/C, tumor necrosis factor α (TNF-α) –308 G/A, and interferon γ (IFN-γ) +874 A/T genes for their possible association with susceptibility to early onset sepsis (EOS) in Saudi newborn infants. A total of 205 newborn infants aged 1-2 days were consecutively enrolled onto the study having met the inclusion criteria (as per the research protocol). DNA was extracted from filter papers using the Chelex-100 method. The cytokines SNP were genotyping using Taqman 5’ nuclease allelic discrimination. For cytokine measurements we used the commercially available Enzyme-Linked Immunosorbent Assay (ELISA) kit. Our results show that the circulating IL-1β, IL-6, TNF-α, and IFN-γ were significantly (p < 0.001) elevated in EOS patients compared to suspected and sepsis-free control groups; and IL-1β –31C, IL-6 –174G, TNF-α –308G, and IFN-γ +874A alleles were associated with EOS in Saudi infants. In conclusion, analysis of cytokines concentrations and SNP for the four tested genes can be used as a predictor of sepsis outcome in newborns.

The evaluation of cord blood interleukin-1β levels in normal and caesarean deliveries

OBJECTIVE

The aim of this prospective study was to establish the cord blood interleukin 1β (IL-1β) levels and asphyxia enzymes in term newborns and their relationship between delivery modes. We investigated whether cord blood level of IL-1β could be used as a reliable marker for detecting hypoxic stress and to determine the optimal cut-off level for IL-1β.

METHODS

The study was designed prospectively. Cord blood samples were obtained at the time of delivery from 75 noninfected full-term neonates for the purpose of measuring cord blood levels of IL-1β. Women were classified into three groups according to the mode of delivery (20 vaginal delivery, 29 urgent caesarean section (with foetal distress) and 26 elective caesarean section). All cases were followed-up by hospitalization. Umbilical cord sampling was carried out for IL-1β, umbilical artery gas parameters and other asphyxia enzymes at the time of delivery. Cord blood IL-1β was measured by enzyme-linked immunosorbent assay. The perinatal outcomes of the cases were recorded after birth. Demographic characteristics, neonatal outcomes and laboratory findings were compared in all the three groups.

RESULTS

IL-1β levels showed statistically significant difference between groups (p < 0.01). The relationship was found between IL-1β cord blood levels and the mode of delivery. IL-1β levels of urgent caesarean section group were significantly higher than elective caesarean section and normal delivery group (p:0.001 and p:0.001, respectively). Normal delivery levels were significantly higher than the elective caesarean group (p:0.001).

CONCLUSION

Urgent section (foetal distress) and vaginal delivery (labour) were each associated with elevated IL-1β cord blood levels in noninfected full-term neonates, while only elective caesarean section was associated with decreased IL-1β levels. For the evaluation of newborns at high risk for perinatal hypoxic stress, cord blood IL-1β levels may lead the way. On the other hand, the mode of delivery may be associated with the effects on the immune system. Further investigations with larger patient groups are required to confirm our results.

Neonatal sepsis: an old problem with new insights

Neonatal sepsis continues to be a common and significant health care burden, especially in very-low-birth-weight infants (VLBW <1500 g). Though intrapartum antibiotic prophylaxis has decreased the incidence of early-onset group B streptococcal infection dramatically, it still remains a major cause of neonatal sepsis. Moreover, some studies among VLBW preterm infants have shown an increase in early-onset sepsis caused by Escherichia coli. As the signs and symptoms of neonatal sepsis are nonspecific, early diagnosis and prompt treatment remains a challenge. There have been a myriad of studies on various diagnostic markers like hematological indices, acute phase reactants, C-reactive protein, procalcitonin, cytokines, and cell surface markers among others. Nonetheless, further research is needed to identify a biomarker with high diagnostic accuracy and validity. Some of the newer markers like inter α inhibitor proteins have shown promising results thereby potentially aiding in early detection of neonates with sepsis. In order to decrease the widespread, prolonged use of unnecessary antibiotics and improve the outcome of the infants with sepsis, reliable identification of sepsis at an earlier stage is paramount.

C-reactive protein: a marker of neonatal stress?

AIM

To assess whether blood values of C-reactive protein (CRP) in healthy term newborns, are influenced by stress.

MATERIAL AND METHODS

Since different types of delivery (vaginal delivery [VD], emergency C-section [EMCS] and elective C-section [ELCS]) are notoriously characterized by different levels of stress for the baby, these three groups were used as models of different levels of stress. The mean CRP values of the three groups obtained in the first hours of life were compared.

RESULTS

We retrieved 1012 babies. Median values (3rd-97th ct) were: 0.05 (0.01-0.46), 0.17 (0.02-1.54), 0.30 (0.04-1.77), 0.43 (0.05-1.31), 0.40 (0.04-1.13) at 12, 24, 48, 72 and 96 h, respectively. Mean values in babies born after VD were statistically higher than those born after C-section, and higher CRP values were present in EMCS with respect to ELCS.

CONCLUSION

This study described normal blood CRP values in a wide population of term babies. An influence of the type of delivery on blood CRP is evident, and this may be explained by the different amount of perinatal stress induced by anyone of the three types of delivery we considered.

The immune system and developmental programming of brain and behavior

The brain, endocrine, and immune systems are inextricably linked. Immune molecules have a powerful impact on neuroendocrine function, including hormone-behavior interactions, during health as well as sickness. Similarly, alterations in hormones, such as during stress, can powerfully impact immune function or reactivity. These functional shifts are evolved, adaptive responses that organize changes in behavior and mobilize immune resources, but can also lead to pathology or exacerbate disease if prolonged or exaggerated. The developing brain in particular is exquisitely sensitive to both endogenous and exogenous signals, and increasing evidence suggests the immune system has a critical role in brain development and associated behavioral outcomes for the life of the individual. Indeed, there are associations between many neuropsychiatric disorders and immune dysfunction, with a distinct etiology in neurodevelopment. The goal of this review is to describe the important role of the immune system during brain development, and to discuss some of the many ways in which immune activation during early brain development can affect the later-life outcomes of neural function, immune function, mood and cognition.

A lifespan approach to neuroinflammatory and cognitive disorders: a critical role for glia

Cognitive decline is a common problem of aging. Whereas multiple neural and glial mechanisms may account for these declines, microglial sensitization and/or dystrophy has emerged as a leading culprit in brain aging and dysfunction. However, glial activation is consistently observed in normal brain aging as well, independent of frank neuroinflammation or functional impairment. Such variability suggests the existence of additional vulnerability factors that can impact neuronal-glial interactions and thus overall brain and cognitive health. The goal of this review is to elucidate our working hypothesis that an individual's risk or resilience to neuroinflammatory disorders and poor cognitive aging may critically depend on their early life experience, which can change immune reactivity within the brain for the remainder of the lifespan. For instance, early-life infection in rats can profoundly disrupt memory function in young adulthood, as well as accelerate age-related cognitive decline, both of which are linked to enduring changes in glial function that occur in response to the initial infection. We discuss these findings within the context of the growing literature on the role of immune molecules and neuroimmune crosstalk in normal brain development. We highlight the intrinsic factors (e.g., chemokines, hormones) that regulate microglial development and their colonization of the embryonic and postnatal brain, and the capacity for disruption or "re-programming" of this crucial process by external events (e.g., stress, infection). An impact on glia, which in turn alters neural development, has the capacity to profoundly impact cognitive and mental health function at all stages of life.

The health implications of birth by Caesarean section

Since the first mention of fetal programming of adult health and disease, a plethora of programming events in early life has been suggested. These have included intrauterine and postnatal events, but limited attention has been given to the potential contribution of the birth process to normal physiology and long-term health. Over the last 30 years a growing number of studies have demonstrated that babies born at term by vaginal delivery (VD) have significantly different physiology at birth to those born by Caesarean section (CS), particularly when there has been no exposure to labour, i.e. pre-labour CS (PLCS). This literature is reviewed here and the processes involved in VD that might programme post-natal development are discussed. Some of the effects of CS are short term, but longer term problems are also apparent. We suggest that VD initiates important physiological trajectories and the absence of this stimulus in CS has implications for adult health. There are a number of factors that might plausibly contribute to this programming, one of which is the hormonal surge or "stress response" of VD. Given the increasing incidence of elective PLCS, an understanding of the effects of VD on normal development is crucial.

Comparable effect of conventional ventilation versus early high-frequency oscillation on serum CC16 and IL-6 levels in preterm neonates

OBJECTIVE

Clara cell 16 kD protein (CC16) and interleukin (IL)-6 have been used as peripheral blood biomarkers of alveolar leakage and inflammation, respectively. Thus, their measurement in the bloodstream could be used to assess ventilator-induced lung injury. The objective of this study was to evaluate the effect of optimized synchronized intermittent mandatory ventilation (SIMV) and high-frequency oscillatory ventilation (HFOV) on circulating CC16 and IL-6 levels when used as the initial ventilation modes in preterm neonates.

STUDY DESIGN

Single center, prospective, randomized clinical study in preterm neonates (gestational age 30 weeks) requiring mechanical ventilation within the first 2 h of life. Serum CC16 and IL-6 were measured on establishment of the assigned ventilation mode after admission, at days 3 and 14 of life as well as at 36 weeks postmenstrual age. Demographic-perinatal data and clinical parameters were also recorded.

RESULT

Of the 30 neonates studied, 24 (gestational age 27.1±1.7 weeks, birth weight 942±214 g) were finally analyzed, equally assigned into the SIMV and HFOV groups. Both groups had comparable demographic-perinatal characteristics and clinical parameters. Serum CC16 and IL-6 altered significantly over time (repeated-measures analysis of variance, both P<0.001). However, changes were not affected by the ventilation mode. Post hoc analysis showed a significant decrease in CC16 and IL-6 from birth up to 36 weeks postmenstrual age in both groups.

CONCLUSION

In preterm neonates, SIMV and HFOV are associated with comparable circulating CC16 and IL-6 levels. These findings suggest a similar alveolar leakage and systemic inflammation with any of the ventilation modes evaluated when their usage is optimized.

Association of tumor necrosis factor β genetic polymorphism and sepsis susceptibility

The association of the tumor necrosis factor β (TNF-β) Nco1 genetic polymorphism with susceptibility to sepsis was evaluated in 60 consecutive patients diagnosed with sepsis and in 148 healthy blood donors. Genomic DNA was extracted from peripheral blood cells and a 782 base-pair fragment of the TNF-β gene was amplified by PCR. The PCR products were subjected to Nco1 restriction digestion and analysed by restriction fragment length polymorphism analysis. Tumor necrosis factor α (TNF-α) and the C-reactive protein (CRP) serum levels were also determined by ELISA and nephelometry, respectively. Among the septic patients, the allelic frequencies of TNFB1 and TNFB2 were 0.2833 and 0.7166, respectively, and they differed from those observed in the blood donors (p=0.0282). The TNFB2 allele frequency was higher in the septic patients than in the blood donors [odds ratio=1.65 (CI 95% 1.02-2.69), p=0.0315]. The TNF-α and CRP serum levels and the APACHE II and SOFA clinical scores did not differ in the patients with the TNFB1 or TNFB2 alleles (p>0.05). The results suggest that the TNFB2 allele is associated with susceptibility to sepsis, but it was not found to be associated with the immunological and clinical biomarkers of the disease.

Early-life programming of later-life brain and behavior: a critical role for the immune system

The immune system is well characterized for its critical role in host defense. Far beyond this limited role however, there is mounting evidence for the vital role the immune system plays within the brain, in both normal, “homeostatic” processes (e.g., sleep, metabolism, memory), as well as in pathology, when the dysregulation of immune molecules may occur. This recognition is especially critical in the area of brain development. Microglia and astrocytes, the primary immunocompetent cells of the CNS, are involved in every major aspect of brain development and function, including synaptogenesis, apoptosis, and angiogenesis. Cytokines such as tumor necrosis factor (TNF)α, interleukin [IL]-1β, and IL-6 are produced by glia within the CNS, and are implicated in synaptic formation and scaling, long-term potentiation, and neurogenesis. Importantly, cytokines are involved in both injury and repair, and the conditions underlying these distinct outcomes are under intense investigation and debate. Evidence from both animal and human studies implicates the immune system in a number of disorders with known or suspected developmental origins, including schizophrenia, anxiety/depression, and cognitive dysfunction. We review the evidence that infection during the perinatal period of life acts as a vulnerability factor for later-life alterations in cytokine production, and marked changes in cognitive and affective behaviors throughout the remainder of the lifespan. We also discuss the hypothesis that long-term changes in brain glial cell function underlie this vulnerability.

Cytokines and preterm labour

Preterm labour and its consequences are the major contributors to perinatal morbidity and mortality worldwide. The prevention of preterm labour and delivery is the single most important challenge to modern obstetrics today. Progress in this area has been hampered by lack of understanding of the basic mechanisms responsible for preterm labour. The implicit paradigm which has governed the study of parturition, is that term and preterm labour are fundamentally the same processes except for the gestational age at which they occur. Indeed, they share a common terminal pathway composed of uterine contractility, cervical dilatation and rupture of membranes. We proposed that while term labour is the result of physiological activation of this common terminal pathway, preterm labour and delivery is the consequence of pathological activation.1Thus, preterm labour may be considered as the response of the fetomaternal unit to a variety of insults (e.g. chorioamnionitis, ischaemia, fetal growth restriction, etc.) (Fig 1) If these insults cannot be effectively handled in the context of a continuing pregnancy, then labour and delivery may occur.

Serum IL-1beta, IL-6, IL-8, and TNF-alpha levels in early diagnosis and management of neonatal sepsis

Aim. To determine serum IL-1β, IL-6, IL-8, and TNF-α levels in neonatal sepsis at the time of diagnosis and after therapy, and to show the meaningful on the follow up. Methods. This prospective study was performed on newborns who were hospitalized for neonatal sepsis and who were classified as culture-proven sepsis (n=12), as culture-negative sepsis (n=21), and as healthy newborns (n=17). Results. At the time of diagnosis, serum IL-1β, IL-6, IL-8, and TNF-α levels of culture-proven sepsis were significantly higher than those of the control groups (P<.05). At the time of diagnosis, IL-1β, IL-6, IL-8, and TNF-α levels of culture-proven sepsis and culture-negative sepsis were significantly higher than levels at the seventh day after antibiotic treatment. Conclusion. Serum IL-1β, IL-6, IL-8, and TNF-α are mediators of inflammation and can be used at the diagnosis and at the evaluation of the therapeutic efficiency in neonatal sepsis.

Maternal plasma interleukin-6, interleukin-1beta and C-reactive protein as indicators of tocolysis failure and neonatal outcome after preterm delivery

OBJECTIVE

To investigate whether maternal serum interleukin-6 (IL-6), interleukin-1beta (IL-1beta) and high sensitive C-reactive protein (CRP) could be used as markers of tocolysis failure and adverse neonatal outcome in pregnancies with preterm labor (PL).

METHODS

Forty-seven maternal blood samples taken because of PL at admission and delivery were analyzed. Control samples were taken from 20 gravidas with normal pregnancies. Differences in interleukins and CRP levels with or without chorioamnionitis, connatal infection or periventricular leukomalacia (PVL) were analyzed. Cut-off values were estimated for prediction of tocolysis failure and adverse neonatal outcome.

RESULTS

All three parameters were significantly higher in patients delivering prematurely than in patients delivering at term. All three parameters were significantly higher with than without histologic chorioamnionitis (p < 0.001), with than without connatal infection (p < 0.01), with than without PVL (p < 0.01 for IL-6 and IL-1beta, p < 0.05 for CRP), and in pregnancies with preterm premature rupture of membranes (PPROM) delivered within 48 hours compared to those more prolonged (p < 0.01). Choosing 50.9 pg/mL of IL-6 and a CRP of 19.7 as cut-offs in maternal blood admission concentrations for neonatal PVL, resulted in sensitivity of 81% and specificity of 91% and sensitivity of 91% and specificity of 81%, respectively. At respective maternal blood admission cut-off levels of 27.8 pg/mL of IL-6 and 8.9 of CRP, both parameters were effective predictors of connatal infection.

CONCLUSIONS

Maternal blood IL-6 and CRP could become useful in predicting tocolysis failure and intrauterine treat for the fetus.

Immunologic markers in the neonatal period: diagnostic value and accuracy in infection

Diagnosis of early-onset neonatal infection has led to the development of several screening tests including C-reactive protein, a very commonly used marker, and cytokines (mainly interleukin-6 and -8), alone or in combination with C-reactive protein, based on the premise that their increases in response to infection may precede that of C-reactive protein. In recent years the search for diagnostic tests has turned to procalcitonin, a propeptide of calcitonin, which appears to be a promising marker of infection in newborn infants. Additionally, specific leukocyte cell surface antigens (mainly CD11b and CD64), detected by flow cytometry, are evaluated as markers of neonatal infection, since their expression on the cell membrane increases in substantial quantities after leukocyte activation by bacteria or their cellular products. This review aims to examine the role of these newly available immunologic indices and to assess their validity as diagnostic markers of infection during the neonatal period.

Cerebral palsy is characterized by protein mediators in cord serum

Cerebral palsy (CP) is a major neurodevelopmental disability in childhood. An association between intrauterine infection and CP has been reported. We examined the relationship between inflammatory mediators in cord serum and CP in term and preterm children. Regional multicenter study was conducted on 19 CP children and 19 gestation-matched paired controls. CP children (n = 27) were further compared with controls of similar gestation at birth (n = 25). Serum levels of 78 protein mediators were analyzed. Eleven analytes correlated with the length of gestation both in cases and controls. In paired analysis, B-lymphocyte chemoattractant, ciliary neurotrophic factor, epidermal growth factor, interleukin (IL)-5, IL-12, IL-13, IL-15, macrophage migration inhibitory factor, monocyte chemoattractant protein-3, monokine induced by interferon gamma, and tumor necrosis factor-related apoptosis-inducing ligand were higher in children with CP (p < or = 0.05). Preterm infants with CP showed higher epidermal growth factor and lower levels of granulocyte-macrophage colony-stimulating factor, IL-2, macrophage-derived chemokine, and pulmonary and activation-regulated chemokine than their paired controls. Inflammatory mediators and growth factors serve as a footprint of the fetal response to an insult manifesting after birth as a permanent brain damage. The cytokine patterns at birth differ between premature and term infants who develop CP.

Proinflammatory cytokines in bovine colostrum potentiate the mitogenic response of peripheral blood mononuclear cells from newborn calves through IL-2 and CD25 expression

Abstract: Bovine colostrum contains high concentrations of cytokines, and colostral cytokines are considered to be an important factor in stimulation of maturation of the immune system in newborns. In this study, 5 proinflammatory cytokines (IL-1beta, IL-6, TNF-alpha, IFN-gamma and IL-1 receptor antagonist, IL-1ra) present in colostrum were tested for their potential to enhance mitogenic response and to elicit expression of IL-2 mRNA and CD25 in peripheral blood mononuclear cells (PBMC) from newborn calves before being fed colostrum. PBMC were pretreated with each recombinant bovine cytokine for 2 hr before stimulation with concanavalin A (ConA). Pretreatment of PBMC from newborn calves with IL-1beta, TNF-alpha or IFN-gamma significantly enhanced the ConA response, whereas IL-1ra inhibited the response. The degree of enhancement or inhibition of mitogenic response by these cytokines was more pronounced in PBMC from newborn calves than in those from adult cows. Although IL-2 mRNA expression in ConA-stimulated PBMC from newborn calves was weaker than that in those from adult cows of ConA-stimulated controls, the expression levels became comparable after pretreatment with IL-1beta, TNF-alpha or IFN-gamma. The CD25 expression in PBMC from newborn calves was also enhanced by pretreatment with IL-1beta, TNF-beta and IFN-gamma. These results suggest that pretreatment of neonatal PBMC with IL-1beta, TNF-alpha or IFN-gamma promotes mitogenic response to ConA through up-regulating the production of IL-2 and the expression of the mature IL-2 receptor.

Role of cytokines (interleukin-1beta, 6, 8, tumour necrosis factor-alpha, and soluble receptor of interleukin-2) and C-reactive protein in the diagnosis of neonatal sepsis

AIM

To investigate whether the serum levels of interleukin-1beta, 6, 8, tumour necrosis factor-alpha and the soluble receptor of IL-2 are useful in the diagnosis of neonatal sepsis, and whether their diagnostic power is increased when in combination with classical markers such as C-reactive protein and white blood cell count.

METHODS

Blood samples were collected at admission from 40 neonates with suspected infection. Patients were included in different groups according to the bacteriological and laboratory results: Group I consisted of 20 newborns with positive blood cultures and other biological tests suggestive of infection. Group II included 20 neonates with negative blood cultures and biological tests not suggestive of infection. The control group included 20 healthy neonates with no clinical or biological data of infection.

RESULTS

Mean values of C-reactive protein were significantly higher in Group I. No differences were found between the groups for white blood cell count, with the exception of the presence of leucocytosis in Group II. Levels of interleukin-1beta, 6, 8, tumour necrosis factor-alpha, soluble receptor of interleukin-2, and C-reactive protein were significantly higher in infected neonates than in the control groups. Detection sensitivity and specificity were 80 and 92% for C-reactive protein, 60 and 87% for interleukin-1beta, 61 and 80% for interleukin-6, 62 and 96% for interleukin-8, 54 and 92% for tumour necrosis factor-alpha and 63 and 94% for soluble receptor of interleukin-2. The discriminant analysis showed that the best combination for sepsis diagnosis was C-reactive protein + interleukin-8 + soluble receptor of interleukin-2, with a sensitivity of 85% and a specificity of 97.1%.

CONCLUSION

Our study suggests that no individual test can on its own identify infected neonates, and that although the combination of C-reactive protein, interleukin-8 and the soluble receptor of interleukin-2 exhibits a high specificity, its sensitivity is limited.

Inflammatory mediators in perinatal asphyxia and infection

AIM

To determine serum levels of interleukin-6 (IL-6), IL-1beta, tumor necrosis factor-alpha (TNF-alpha), soluble intercellular adhesion molecule-1 (sICAM-1) and C-reactive protein (CRP) in asphyxiated neonates and compare these inflammatory factors with those found in neonates with perinatal infection.

METHODS

88 neonates were studied, of whom 36 were asphyxiated, 18 were infected and the remaining 34 were controls. Peripheral blood samples were obtained on the 1st, 3rd and 5th postnatal days.

RESULTS

Cytokines IL-6 and IL-1beta as well as sICAM-1 serum levels did not differ between asphyxiated and infected neonates; however, at most time periods, their values were significantly higher than controls. TNF-alpha was similar in the three groups of neonates. CRP serum values were significantly higher in the infected neonates than in the asphyxiated or control subjects. Among the 54 asphyxiated and infected neonates, 15 were considered as severe cases and 39 as mild. The severe cases, at most time periods, had significantly higher IL-6, IL-1beta and sICAM-1 levels compared with the mild ones. Through receiver operating characteristic curves the cut-off points, sensitivities, and specificities for distinguishing neonates at risk or at high risk for brain damage were established.

CONCLUSION

Similar increases in serum levels of IL-6, IL-1beta and sICAM-1 were found in perinatally asphyxiated and infected neonates. As these increases correlated with the severity of the perinatal insults, neonates at high risk for brain damage might be detected.

C-reactive protein, interleukin-6, and procalcitonin in the immediate postnatal period: influence of illness severity, risk status, antenatal and perinatal complications, and infection

BACKGROUND

Studies of the diagnostic accuracy of most laboratory tests for early-onset neonatal sepsis have yielded variable results. We investigated whether some of this variation might be attributable to differences in population baseline severity and risk status as well as to specific ante- and perinatal variables, independent of the presence of neonatal infection.

METHODS

The Score for Neonatal Acute Physiology (SNAP) was used to define illness severity, with SNAP Perinatal Extension (SNAP-PE) used to define the combined physiologic and perinatal mortality risk. A total of 134 ill newborns (19 with early-onset infection and 115 with no infection) were available for simultaneous analysis of the association of SNAP, SNAP-PE, and maternal and perinatal variables with C-reactive protein (CRP), interleukin-6 (IL-6), and procalcitonin (PCT) concentrations at birth and at 24 and 48 h of life.

RESULTS

Early-onset neonatal infection was associated with significant increases in CRP, IL-6, and PCT concentrations at all three time points, independent of illness severity. However, among babies without infection, higher SNAP and SNAP-PE scores were associated with higher IL-6 concentrations at birth. Certain maternal or perinatal variables altered IL-6 and PCT values in the infected as well as in the uninfected neonates. However, if different cutoff points were used at any of the three neonatal ages, PCT sensitivity and specificity were greater than those of CRP or IL-6.

CONCLUSIONS

Illness severity and risk status are unlikely to interfere with the use of CRP and PCT for detection of early-onset neonatal sepsis. In contrast, the diagnostic value of IL-6 at birth may be altered by physiologic severity and risk indexes. The reliability of CRP, IL-6, and PCT for the diagnosis of early-onset neonatal infection requires specific cutoff values for each evaluation time point over the first 48 h of life.

Clinical chorioamnionitis, elevated cytokines, and brain injury in term infants

OBJECTIVES

To determine the initial inflammatory cytokine response in term infants born to mothers with clinical chorioamnionitis and to assess whether the cytokine response is associated with birth depression, abnormal neurologic examination, and hypoxic-ischemic encephalopathy (HIE).

METHODS

Infants who were exposed to chorioamnionitis and admitted to the neonatal intensive care unit (n = 61) were studied prospectively. Cytokine concentrations were measured from umbilical cord blood and at 6 and 30 hours after birth. Control values (n = 50) were determined from cord blood of healthy term infants. Enzyme-linked immunosorbent assays were performed for interleukin (IL)-1beta; IL-6; IL-8; regulated on activation, normal T-cell expressed and secreted (RANTES); macrophage inflammatory protein-1alpha; and tumor necrosis factor-alpha. Serial blinded neurologic examinations using a modified Dubowitz score were performed simultaneously at 6 and 30 hours.

RESULTS

Cord IL-6 (1071 +/- 1517 vs 65 +/- 46 pg/mL), IL-8 (2580 +/- 9834 vs 66 +/- 57 pg/mL), and RANTES (95 917 +/- 16 518 vs 54 000 +/- 14 306 pg/mL) concentrations only were higher in infants with chorioamnionitis versus control infants. IL-6 increased at 6 hours to 1451 +/- 214 pg/mL, followed by a 5-fold decline at 30 hours in contrast to progressive decreases over time in IL-8 and RANTES. There was no relationship between cytokines and birth depression. Modified Dubowitz score correlated with IL-6 at 6 hours (r = 0.5). Infants with HIE/seizures (n = 5) had significantly higher cytokine concentrations at 6 hours versus infants without either (n = 56): IL-6 (3130 vs 1219 pg/mL), IL-8 (5433 vs 780 pg/mL), and RANTES (97 396 vs 46 914 pg/mL).

CONCLUSIONS

There was a significant association between abnormalities in the neurologic examination and cytokine concentrations, with the highest cytokines concentrations observed in infants who developed HIE/seizures.

Expression of CD64 as a potential marker of neonatal sepsis

The aim of this study was to identify a novel immunological indicator useful for the early diagnosis (through a rapid and single determination) of neonatal sepsis (NS). Peripheral blood samples were taken from 63 neonates, who were classified into four groups: proven NS (n = 17); clinical NS (n = 14); disease without infection (n = 17); and healthy newborns (n = 15). Neutrophil expression of CD64, CD43, CD44, CD50, CD62L and Mac-1, and plasma levels of interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha (TNF-alpha) and soluble L-selectin (sCD62L), were determined. Expression of CD64 was significantly enhanced in the group with proven sepsis and clinical NS compared to newborns without infection (p < 0.05). Eight newborns with proven or clinical sepsis, but only one with disease without infection, showed an increased percentage of CD64+ cells (diagnostic specificity = 96.8%). No significant differences were found in the expression of the other leucocyte differentiation antigens studied. As previously described, TNF-alpha and IL-6 levels were significantly elevated in newborns with proven or clinical sepsis compared to neonates without infection (p < 0.05). Our results suggest that, through a single determination, the enhanced expression of CD64 is a highly specific indicator of NS, although its diagnostic sensitivity is low (25.8%). In contrast, we found that plasma levels of IL-1beta and sCD62L, as well as the expression of Mac-1, CD43, CD44, CD50, and CD62L, do not appear to be useful for the diagnosis of NS.

Elevated levels of lipopolysaccharide-binding protein and soluble CD14 in plasma in neonatal early-onset sepsis

No data on lipopolysaccharide-binding protein (LBP) in newborns with sepsis have been available up to now. We therefore determined levels of LBP and soluble CD14 (sCD14) in plasma of healthy and septic neonates in order to evaluate their potential diagnostic role. The study included prospectively collected patient samples of two recently published studies on cytokine expression in neonatal sepsis. Twenty-nine septic patients were enrolled in the present analysis. Samples--either cord blood or peripheral blood--from patients admitted within the first 24 h of life for suspicion of sepsis and cord blood samples of a control group of 40 healthy mature infants delivered spontaneously were analyzed. For seven patients of the septic group, a second sample collected between 24 and 48 h of life was available. Levels of sCD14 and LBP in plasma were determined by an enzyme immunoassay using recombinant CD14 and LBP as standards. LBP and sCD14 were correlated to cytokine plasma levels. In septic neonates, LBP (median, 36.6 versus 7.8 microg/ml; P < 0.001) and sCD14 (median, 0.42 versus 0.28 microg/ml; P < 0.001) levels were highly elevated when compared to those of healthy neonates and strongly correlated to granulocyte colony-stimulating factor (G-CSF), interleukin-1beta (IL-1beta), IL-6, and IL-8 levels. LBP levels in septic neonates analyzed between 24 and 48 h of life even increased when compared to samples obtained at or shortly after delivery (median, 36.6 versus 60 microg/ml; P = 0.038). In summary, levels of LBP in plasma of neonates with early-onset sepsis are significantly elevated; the elevated plasma levels seem to persist for more than 24 h, which could provide the clinician with a prolonged time period to identify the newborn with bacterial sepsis.

Increase of cord blood cytokine-producing T cells in intrauterine infection

BACKGROUND

Although infection is a frequent and important cause of morbidity and mortality in the neonatal period, evaluation of the immune system in cases of intrauterine infection is not easy. The subsets of T helper (Th) 1, which produce mainly interferon gamma (IFN-gamma), and Th2, which produce interleukin (IL) -4, have been implicated in the regulation of many immune responses. In this study, we investigated Th1 and Th2 subsets in the cord blood (CB) to evaluate the role of CB T cells in the intrauterine infections.

METHODS

We used an intracellular cytokine-staining technique with determination by flow cytometry to study IFN-gamma-producing T cells and IL-4-producing T cells in the CB of six neonates with perinatal intrauterine infection and 17 uninfected neonates.

RESULTS

The CB from neonates with intrauterine infections had more IFN-gamma-producing CD3+T cells than that from uninfected neonates. The percentage of CB IFN-gamma-producing CD3+T cells in the infected neonates correlated with the duration of membrane rupture before the onset of labor, but not with the level of C-reactive protein. The infected neonate born after the longest duration of membrane rupture showed an increased percentage of IL-4-producing CD3+T cells.

CONCLUSIONS

Our results suggest that the increase of CB IFN-gamma and IL-4- producing T cells is part of the immune system directed against perinatal intrauterine infections.

Intracellular cytokine production by fetal and adult monocytes

BACKGROUND/PURPOSE

In light of the neonate's increased susceptibility to systemic infection, the authors hypothesized that adult and fetal monocytes have different cytokine expression profiles in response to lipopolysaccharide (LPS), and interleukin (IL)-11, a counter-inflammatory cytokine.

METHODS

Samples of cord blood (n = 30) and adult blood (n = 30) were obtained and treated as follows: control (baseline expression), LPS exposure, and IL-11 or IL-11+LPS exposure. After incubation with a protein transport inhibitor, mononuclear cells were stained for intracellular tumor necrosis factor (TNF)-alpha, IL-1beta, IL-6, and IL-8. Each sample was then analyzed by flow cytometry for cytokine expression. Cytokine production was measured by the percent positive as well as the fluorescence index for each cytokine. Analysis of variance (ANOVA) and Students t tests were used for statistical analysis.

RESULTS

Baseline levels of IL-8 were significantly higher for fetal monocytes (P <.0001). After LPS exposure, fetal monocytes produced less TNF-alpha (P =.0105) and more IL-8 (P <.0007) relative to adult cells. IL-11 treatment reduced baseline production of IL-8 in fetal and adult monocytes (P <.05).

CONCLUSIONS

These results suggest that neonatal monocytes portray a different cytokine expression profile compared with adult monocytes. IL-11 treatment appears to alter the IL-8 expression of resting fetal and adult monocytes.

Effect of interleukin-1 receptor antagonist on concanavalin A response of peripheral blood mononuclear cells from newborn calves

The coexistence of interleukin (IL)-1beta with IL-1 receptor antagonist (ra) in bovine colostrum and the possibility of simultaneous transfer of these cytokines to neonates via colostrum have been demonstrated. In the present study, we investigated the effect of IL-1ra on the mitogenic response of calf peripheral blood mononuclear cells (PBMC) stimulated by concanavalin A (ConA), which was mediated by IL-1. Pretreatment of PBMC with recombinant bovine (rb) IL-1ra alone significantly suppressed the proliferation of ConA-stimulated cells. However, in the presence of rbIL-1beta, the suppressive activity of rbIL-1ra was counteracted. These results suggest that coexistence of IL-1ra with IL-1 in colostrum may have no effect on the activation of the neonatal immune system by IL-1beta.

Umbilical vein interleukin 6 and tumor necrosis factor alpha plasma concentrations in the very preterm infant

OBJECTIVE

To examine the relationship between umbilical vein plasma concentrations of interleukin 6 (IL-6) and tumor necrosis factor (TNF)-alpha and early neonatal sepsis in the very preterm infant, and the histopathologic findings of chorioamnionitis in the placentas from these pregnancies.

METHODS

A prospective study was conducted in 43 very preterm, singleton infants delivered at or before 32 weeks of gestation. IL-6 and TNF-alpha were measured by enzyme-linked immunoassay. Placentas from these pregnancies were histologically examined for the presence of chorioamnionitis. Infants were prospectively classified as confirmed sepsis group, clinical sepsis group or control group. IL-6 and TNF-alpha plasma concentrations were not normally distributed, so they were transformed to their natural log values for statistical analysis.

RESULTS

The enrolled infants had a mean gestational age of 27.2 +/- 2.7 weeks and a mean birth weight of 956 +/- 325 g. Three (7%) infants had confirmed sepsis, 18 (42%) were in the clinical sepsis group and 22 (51%) were in the control group. IL-6 concentrations but not TNF-alpha were significantly higher (P < 0.05) in the confirmed (8.9 +/- 1.7) and clinical sepsis (5.5 +/- 2.4) groups in comparison with the control group (2.1 +/- 1.6). We examined 42 placentas. Twenty-three (55%) had no evidence of chorioamnionitis, 1 (2%) had mild grade, 8 (19%) had a moderate grade and 10 (24%) had a severe grade of chorioamnionitis. IL-6 was significantly elevated in the moderate (5.9 +/- 1.6 vs. 1.9 +/- 1.6) and severe grade (7.2 +/- 2.3 vs. 1.9 +/- 1.6) of chorioamnionitis, in the presence of acute deciduitis (6.0 +/- 2.7 vs. 2.1 +/-1.8), chorionic vasculitis (6.8 +/- 2.1 vs. 2.2 +/- 1.9) and funisitis (7.3 +/- 1.9 vs. 2.7 +/- 2.3) (P < 0.05) TNF-alpha plasma concentrations were not significantly different.

CONCLUSION

An elevated umbilical vein IL-6 concentration is a good indicator of sepsis syndrome in the very preterm infant and also correlates with histologic chorioamnionitis in these pregnancies.

Fetal distress increases interleukin-6 and interleukin-8 and decreases tumour necrosis factor-alpha cord blood levels in noninfected full-term neonates

OBJECTIVE

To assess the influence of fetal distress on interleukin-1beta, interleukin-6, interleukin-8 and on tumour necrosis factor-alpha blood levels in noninfected full-term neonates.

STUDY DESIGN

In a multicentre prospective study, cord blood samples were obtained at time of delivery from 234 noninfected full-term neonates for the purposes of measuring serum levels of interleukin-1beta, interleukin-6, interleukin-8 and tumour necrosis factor-alpha using immunoassays. Women were classified into four groups according to the mode of delivery (vaginal delivery or caesarean section) and the presence or absence of fetal distress. The role of labour was also investigated.

RESULTS

No significant relationship was found between cytokine cord blood levels and the mode of delivery. Fetal distress was associated with an increase in interleukin-6 (P = 0.01) and interleukin-8 (P < 0.001) levels, and a decrease in tumour necrosis factor-alpha (P < 0.001). Labour was also associated with a significant increase in interleukin-6 and interleukin-8 cord blood levels (P = 0.01 and P < 0.001, respectively).

CONCLUSION

Fetal distress and labour were each associated with elevated interleukin-6 and interleukin-8 cord blood levels in noninfected full term neonates while only fetal distress was associated with decreased tumour necrosis factor-alpha levels.

Patterns of inflammatory cytokine serum concentrations during the perinatal period

Inflammatory cytokines interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were measured in the serum of healthy, term neonates on the first (N1), fifth (N5) and 40th (N40) day after birth, compared with those in maternal serum (MS), umbilical cord (UC) and in adult controls. All three cytokines were significantly elevated in N1 and N5, compared with those in UC and adults (P < 0.0001). IL-1beta and IL-6 declined significantly from N1 to N40 (P < 0.0001), while TNF-alpha increased significantly from N1 to N5 and declined thereafter. TNF-alpha values in UC were significantly higher than in adults, but lower than in N40 (P < 0.0001), while IL-1beta and IL-6 values in UC did not differ from those in N40 and in adults. IL-1beta and IL-6, but not TNF-alpha values in MS were significantly higher than those in controls (P < 0.0001). IL-1beta values in MS were significantly higher than those in N1 (P < 0.0001), while those of IL-6 and TNF-alpha were significantly lower (P < 0.0001). Moreover, IL- 1beta values were dependent on the mode of delivery in N1 (P < 0.001), in MS (P < 0.02) and in UC (0.03), while IL-1beta and TNF-alpha values in N1 were strongly interrelated (r = 0.7; P < 0.01). In conclusion, the increased values of IL-1beta, IL-6 and TNF-alpha during the perinatal period might reflect a newborn immune response to the stress of delivery and to environmental changes after birth.