Neutrophil CD11b expression as a diagnostic marker for early-onset neonatal infection

Quantitative Proteomic Analysis Identifying and Evaluating TRAF6 and IL-8 as Potential Diagnostic Biomarkers in Neonatal Patients with Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a common gastrointestinal complication in premature infants, resulting in high morbidity and mortality, and its early detection is crucial for accurate treatment and outcome prediction. Extensive research has demonstrated a clear correlation between NEC and extremely low birth weight, degree of preterm, formula feeding, infection, hypoxic/ischemic damage, and intestinal dysbiosis. The development of noninvasive biomarkers of NEC from stool, urine, and serum has attracted a great deal of interest because to these clinical connections and the quest for a deeper knowledge of disease pathophysiology. Therefore, this study aims to identify protein expression patterns in NEC and discover innovative diagnostic biomarkers. In this study, we recruited five patients diagnosed with NEC and paired necrotic segments of intestinal tissue with adjacent normal segments of intestine to form experimental and control groups. Quantitative proteomics tandem mass tagging (TMT) labeling technique was used to detect and quantify the proteins, and the expression levels of the candidate biomarkers in the intestinal tissues were further determined by quantitative polymerase chain reaction (RT-qPCR), Western blot analysis, Immunofluorescence methods and enzyme-linked immunosorbent assay (ELISA). A total of 6880 proteins were identified and quantified in patients with NEC. A significant disparity in protein expression was observed between necrotic and normal segments of intestinal tissue in NEC patients. A total of 55 proteins were found to be upregulated, and 40 proteins were found to be downregulated in NEC patients when using a p-value of < 0.05, and an absolute fold change of > 1.2 for analysis. GO function enrichment analysis showed the positive regulation of significant biological processes such as mitochondrial organization, vasoconstriction, rRNA catabolism, fluid shear stress response, and glycerol ether biosynthesis processes. Enrichment analysis also revealed essential functions such as ligand-gated ion channel activity, potassium channel activity, ligand-gated cation channel activity, ligand-gated ion channel activity, and ligand-gated channel activity, including molecular functions such as ligand-gated ion channel activity and mitotic events in this comparative group. Significant changes were found in endomembrane protein complex, membrane fraction, mitochondrial membrane fraction, membrane components, membrane intrinsic components, and other localized proteins. Additional validation of intestinal tissue and serum revealed a substantial increase in TRAF6 (tumor necrosis factor receptor-associated factor 6) and IL-8(Interleukin-8, CXCL8). The quantitative proteomic TMT method can effectively detect proteins with differential expression in the intestinal tissues of NEC patients. Proteins TRAF6 and CXCL8/IL-8 are significantly upregulated in the intestinal tissues and serum samples of patients and may serve as valuable predictor factors for NEC's early diagnosis.

Multi-modal sensing with integrated machine learning to differentiate specific leukocytes targeted by electrically sensitive hybrid particles

The growing need for personalized, accurate, and non-invasive diagnostic technology has resulted in significant advancements, from pushing current mechanistic limitations to innovative modality developments across various disease-related biomarkers. However, there still lacks clinical solutions for analyzing multiple biomarkers simultaneously, limiting prognosis for patients suffering with complicated diseases or comorbidities. Here, we conceived, fabricated, and validated a multifrequency impedance cytometry apparatus with novel frequency-sensitive barcoded metal oxide Janus particles (MOJPs) as cell-receptor targeting agents. These microparticles are modulated by a metal oxide semi-coating which exhibit electrical property changes in a multifrequency electric field and are functionalized to target CD11b and CD66b membrane proteins on neutrophils. A multi-modal system utilizing supervised machine learning and simultaneous high-speed video microscopy classifies immune-specific surface receptors targeted by MOJPs as they form neutrophil-MOJP conjugates, based on multivariate multifrequency electrical recordings. High precision and sensitivity were determined based on the type of MOJPs conjugated with cells (>90% accuracy between neutrophil-MOJP conjugates versus cells alone). Remarkably, the design could differentiate the number of MOJPs conjugated per cell within the same MOJP class (>80% accuracy); which also improved comparing electrical responses across different MOJP types (>75% accuracy) as well. Such trends were consistent in individual blood samples and comparing consolidated data across multiple samples, demonstrating design robustness. The configuration may further expand to include more MOJP types targeting critical biomarker receptors in one sample and increase the modality's multiplexing potential.

Selective modulation of monocyte and neutrophil responses with activated protein C in preterm infants

BACKGROUND

Inflammation is associated with many disorders of preterm infants including periventricular leukomalacia, chronic lung disease, and necrotizing enterocolitis. Activated protein c (APC) has shown positive immunomodulatory effects.

OBJECTIVES

We aimed to study neutrophil and monocyte function in response to lipopolysaccharide (LPS) and APC stimulation ex vivo in preterm infants <32 weeks gestation over the first week of life compared to neonatal and adult controls.

METHODS

Peripheral blood was taken on day 1, 3, and 7 and stimulated with LPS in the absence or presence of APC. Expression of toll-like receptor 4 (TLR4) and CD11b and reactive oxygen intermediate (ROI) release from neutrophils and monocytes was examined by flow cytometry.

RESULTS

LPS induced neutrophil ROI in adults and preterm infants and was significantly reduced by APC. Baseline and LPS-induced monocyte ROI production in preterm neonates was increased compared to adult and term controls. Neutrophil TLR4 baseline expression was higher in term controls compared to preterm infants.

CONCLUSION

Increased systemic ROI release in preterm infants may mediate tissue damage, ROI was reduced by APC. However, due to the high risk of hemorrhage further examination of APC mutant forms with anti-inflammatory but decreased anticoagulant properties is merited.

Reduction of Neutrophil Activation by Phosphodiesterase 4 Blockade in Behçet's Disease

OBJECTIVE

Behçet's disease (BD) is a systemic vasculitis with inflammatory lesions mediated by cytotoxic T cells and neutrophils. Apremilast, an orally available small-molecule drug that selectively inhibits phosphodiesterase 4 (PDE4), has been recently approved for the treatment of BD. We aimed to investigate the effect of PDE4 inhibition on neutrophil activation in BD.

METHODS

We studied surface markers and reactive oxygen species (ROS) production by flow cytometry, and neutrophil extracellular traps (NETs) production and molecular signature of neutrophils by transcriptome analysis before and after PDE4 inhibition.

RESULTS

Activation surface markers (CD64, CD66b, CD11b, and CD11c), ROS production, and NETosis were up-regulated in BD patient neutrophils compared to healthy donor neutrophils. Transcriptome analysis revealed 1,021 significantly dysregulated neutrophil genes between BD patients and healthy donors. Among dysregulated genes, we found a substantial enrichment for pathways linked to innate immunity, intracellular signaling, and chemotaxis in BD. Skin lesions of BD patients showed increased infiltration of neutrophils that colocalized with PDE4. Inhibition of PDE4 by apremilast strongly inhibited neutrophil surface activation markers as well as ROS production, NETosis, and genes and pathways related to innate immunity, intracellular signaling, and chemotaxis.

CONCLUSION

We highlight key biologic effects of apremilast on neutrophils in BD.

Predictors of Mortality in Early Neonatal Sepsis: A Single-Center Experience

Background and Objectives: Early neonatal sepsis is associated with a significant mortality rate despite modern treatment strategies. Our aim was to identify risk factors contributing to the occurrence of death in newborns with early neonatal sepsis. Materials and Methods: We conducted a retrospective cross-sectional study that included newborns with early sepsis who received care in the intensive and semi-intensive care units at the Institute of Neonatology, Belgrade, Serbia. Newborns with early neonatal sepsis who died comprised the case group, whereas those who survived made up the control group. The diagnostic and therapeutic approach to the septic condition was carried out independently of this study, according to valid hospital protocols and current good practice guidelines. The influence of a large number of variables on the examined dichotomous outcome, as well as the mutual interaction of potential predictor variables, was examined by binary logistic regression. Results: The study included 133 pregnant women and 136 newborns with early neonatal sepsis, of which 51 (37.5%) died, while the remaining 85 newborns (62.5%) survived. Newborns who died had a statistically significantly lower birth weight compared to those who survived (882.8 ± 372.2 g vs. 1660.9 ± 721.1 g, p = 0.000). Additionally, compared to newborns who survived, among the deceased neonates there was a significantly higher proportion of extremely preterm newborns (74.5% vs. 22.4%, p = 0.000). The following risk factors for the occurrence of death in early neonatal sepsis were identified: low birth weight, sepsis caused by gram-negative bacteria, and the use of double-inotropic therapy and erythrocyte transfusion during the first week. Conclusions: Pediatricians should pay special attention to infants with early neonatal sepsis in whom any of the identified risk factors are present in order to prevent a fatal outcome.

The extracellular sialidase NEU3 primes neutrophils

Some extracellular glycoconjugates have sialic acid as the terminal sugar, and sialidases are enzymes that remove this sugar. Mammals have 4 sialidases and can be elevated in inflammation and fibrosis. In this report, we show that incubation of human neutrophils with the extracellular human sialidase NEU3, but not NEU1, NEU2 or NEU4, induces human male and female neutrophils to change from a round to a more amoeboid morphology, causes the primed human neutrophil markers CD11b, CD18, and CD66a to localize to the cell cortex, and decreases the localization of the unprimed human neutrophil markers CD43 and CD62-L at the cell cortex. NEU3, but not the other 3 sialidases, also causes human male and female neutrophils to increase their F-actin content. Human neutrophils treated with NEU3 show a decrease in cortical levels of Sambucus nigra lectin staining and an increase in cortical levels of peanut agglutinin staining, indicating a NEU3-induced desialylation. The inhibition of NEU3 by the NEU3 inhibitor 2-acetylpyridine attenuated the NEU3 effect on neutrophil morphology, indicating that the effect of NEU3 is dependent on its enzymatic activity. Together, these results indicate that NEU3 can prime human male and female neutrophils, and that NEU3 is a potential regulator of inflammation.

The balance between protective and pathogenic immune responses to pneumonia in the neonatal lung is enforced by gut microbiota

Although modern clinical practices such as cesarean sections and perinatal antibiotics have improved infant survival, treatment with broad-spectrum antibiotics alters intestinal microbiota and causes dysbiosis. Infants exposed to perinatal antibiotics have an increased likelihood of life-threatening infections, including pneumonia. Here, we investigated how the gut microbiota sculpt pulmonary immune responses, promoting recovery and resolution of infection in newborn rhesus macaques. Early-life antibiotic exposure interrupted the maturation of intestinal commensal bacteria and disrupted the developmental trajectory of the pulmonary immune system, as assessed by single-cell proteomic and transcriptomic analyses. Early-life antibiotic exposure rendered newborn macaques more susceptible to bacterial pneumonia, concurrent with increases in neutrophil senescence and hyperinflammation, broad inflammatory cytokine signaling, and macrophage dysfunction. This pathogenic reprogramming of pulmonary immunity was further reflected by a hyperinflammatory signature in all pulmonary immune cell subsets coupled with a global loss of tissue-protective, homeostatic pathways in the lungs of dysbiotic newborns. Fecal microbiota transfer was associated with partial correction of the broad immune maladaptations and protection against severe pneumonia. These data demonstrate the importance of intestinal microbiota in programming pulmonary immunity and support the idea that gut microbiota promote the balance between pathways driving tissue repair and inflammatory responses associated with clinical recovery from infection in infants. Our results highlight a potential role for microbial transfer for immune support in these at-risk infants.

Biomarkers of Neonatal Sepsis: From Being Mere Numbers to Becoming Guiding Diagnostics

Neonatal sepsis is a common cause of neonatal morbidity and mortality. The diagnosis of newborn sepsis is still difficult. Different early objective diagnostic tests or specific signs and symptoms, particularly in preterm infants, make it difficult to diagnose neonatal sepsis. This review article describes biomarkers and their role in the early diagnosis, treatment, and prognosis of neonatal sepsis. It also explores the possible advances and future prospects of these biomarkers. An ideal sepsis biomarker will not only help in the guidance of the use of antibiotics when not needed but also the duration of the course of antibiotics if sepsis is proven. It should also have high sensitivity, specificity, positive predictive value, and negative predictive value. These biomarkers hold a promising position in the management of neonatal sepsis and translate into use in clinical settings. Metabolomics, a diagnostic method based on detecting metabolites found in biological fluids, may open new possibilities in the management of critically ill newborns.

Neutrophil Activation/Maturation Markers in Chronic Heart Failure with Reduced Ejection Fraction

BACKGROUND

Neutrophils are critically involved in the immune response. Inflammatory stimuli alter the expression status of their surface molecule toolset, while inflammation-stimulated granulopoiesis might also influence their maturation status. Data on neutrophil status in heart failure with reduced ejection fraction (HFrEF) are scarce. The present study aims to evaluate the role of neutrophil CD11b, CD66b and CD64 expression in HFrEF.

METHODS

A total of 135 HFrEF patients and 43 controls were recruited. Mean fluorescence intensity of the activation/maturation markers CD11b, CD66b and CD64 was measured on neutrophils by flow cytometry. CD10 (neprilysin) expression was simultaneously determined.

RESULTS

Neutrophil CD64 expression was higher in HFrEF compared with controls, while CD11b/CD66b levels were similar. Neutrophil CD11b and CD66b showed a significant direct correlation to neutrophil CD10 expression (rs = 0.573, p < 0.001 and rs = 0.184, p = 0.033). Neutrophil CD11b and CD66b correlated inversely with heart failure severity reflected by NT-proBNP and NYHA class (NT-proBNP: rs = -0.243, p = 0.005 and rs = -0.250, p = 0.004; NYHA class: p = 0.032 and p = 0.055), whereas no association for CD64 could be found. Outcome analysis did not reveal a significant association between the expression of CD11b, CD66b and CD64 and all-cause mortality (p = ns).

CONCLUSIONS

The results underline the potential role of neutrophils in HFrEF disease pathophysiology and risk stratification and should stimulate further research, characterizing subpopulations of neutrophils and searching for key molecules involved in the downward spiral of inflammation and heart failure.

Renal Denervation Exacerbates LPS- and Antibody-induced Acute Kidney Injury, but Protects from Pyelonephritis in Mice

BACKGROUND

Renal denervation (RDN) is an invasive intervention to treat drug-resistant arterial hypertension. Its therapeutic value is contentious. Here we examined the effects of RDN on inflammatory and infectious kidney disease models in mice.

METHODS

Mice were unilaterally or bilaterally denervated, or sham operated, then three disease models were induced: nephrotoxic nephritis (NTN, a model for crescentic GN), pyelonephritis, and acute endotoxemic kidney injury (as a model for septic kidney injury). Analytical methods included measurement of renal glomerular filtration, proteinuria, flow cytometry of renal immune cells, immunofluorescence microscopy, and three-dimensional imaging of optically cleared kidney tissue by light-sheet fluorescence microscopy followed by algorithmic analysis.

RESULTS

Unilateral RDN increased glomerular filtration in denervated kidneys, but decreased it in the contralateral kidneys. In the NTN model, more nephritogenic antibodies were deposited in glomeruli of denervated kidneys, resulting in stronger inflammation and injury in denervated compared with contralateral nondenervated kidneys. Also, intravenously injected LPS increased neutrophil influx and inflammation in the denervated kidneys, both after unilateral and bilateral RDN. When we induced pyelonephritis in bilaterally denervated mice, both kidneys contained less bacteria and neutrophils. In unilaterally denervated mice, pyelonephritis was attenuated and intrarenal neutrophil numbers were lower in the denervated kidneys. The nondenervated contralateral kidneys harbored more bacteria, even compared with sham-operated mice, and showed the strongest influx of neutrophils.

CONCLUSIONS

Our data suggest that the increased perfusion and filtration in denervated kidneys can profoundly influence concomitant inflammatory diseases. Renal deposition of circulating nephritic material is higher, and hence antibody- and endotoxin-induced kidney injury was aggravated in mice. Pyelonephritis was attenuated in denervated murine kidneys, because the higher glomerular filtration facilitated better flushing of bacteria with the urine, at the expense of contralateral, nondenervated kidneys after unilateral denervation.

Neutrophils: Need for Standardized Nomenclature

Neutrophils are the most abundant innate immune cell with critical anti-microbial functions. Since the discovery of granulocytes at the end of the nineteenth century, the cells have been given many names including phagocytes, polymorphonuclear neutrophils (PMN), granulocytic myeloid derived suppressor cells (G-MDSC), low density neutrophils (LDN) and tumor associated neutrophils (TANS). This lack of standardized nomenclature for neutrophils suggest that biologically distinct populations of neutrophils exist, particularly in disease, when in fact these may simply be a manifestation of the plasticity of the neutrophil as opposed to unique populations. In this review, we profile the surface markers and granule expression of each stage of granulopoiesis to offer insight into how each stage of maturity may be identified. We also highlight the remarkable surface marker expression profiles between the supposed neutrophil populations.

Oral dimethyl fumarate induces changes within the peripheral neutrophil compartment of patients with psoriasis that are linked with skin improvement

BACKGROUND

Dimethyl fumarate (DMF) is a treatment for moderate-to-severe psoriasis and multiple sclerosis. DMF therapy typically improves skin inflammation within the first 3 months of treatment. DMF is a prodrug that generates the hydroxycarboxylic acid receptor 2 (HCA2) agonist, monomethyl fumarate (MMF). Despite widespread clinical use, DMF's mechanism of action is not fully understood.

OBJECTIVES

We wished to characterize the changes induced by DMF in peripheral neutrophils within the first 3 months of treatment to better understand its early antipsoriatic effects.

METHODS

Flow cytometry was used to assess T-cell and neutrophil frequencies, apoptosis and activation phenotype. In vitro culture of neutrophils with DMF and MMF was used to evaluate apoptosis and HCA2 internalization. Serum levels of neutrophil degranulation products were measured by enzyme-linked immunosorbent assay.

RESULTS

Patients with psoriasis had significantly higher leucocyte counts at baseline compared with controls, with a large population of pro-inflammatory CD62L^lo  CD11b^bright neutrophils. Analysis revealed that DMF treatment reduced the frequency of CD62L^lo  CD11b^bright neutrophils and serum levels of neutrophil activation markers. This reduction was not linked to increased apoptosis.

CONCLUSIONS

Our results reveal a novel in vivo effect of DMF therapy on pro-inflammatory neutrophils that likely contributes to this treatment's antipsoriatic efficacy.

Cell-Surface Biomarkers, C-Reactive Protein and Haematological Parameters for Diagnosing Late Onset Sepsis in Pre-term Neonates

OBJECTIVE

To compare the diagnostic accuracy of white blood cell-surface biomarkers (CD64, CD11b and HLA-DR), C-reactive protein (CRP) and hematological parameters to diagnose definite sepsis among pre-term neonates presenting with suspected late-onset neonatal sepsis (LONS).

DESIGN

This was a prospective, single-gate, diagnostic study in a Level III neonatal unit. Fifty-three neonates (gestation, <34 weeks) with LONS (onset, >72  age), were enrolled. Cell-surface biomarkers, CRP and haematological parameters were assayed at 0 and 48 h after onset. The reference standard was definite sepsis, defined as a positive blood culture with a non-contaminant organism. The index tests (cell-surface biomarkers, CRP and haematological parameters) were compared between subjects with or without 'definite sepsis'. The area under the receiver operator characteristics curves (AUC) generated for each index test at 0 and 48 h was compared.

SETTING

Level III neonatal unit in a tertiary care institute.

RESULTS

Of 53 enrolled pre-term infants, 24 had definite sepsis. Among all the index tests evaluated, CRP at 48 h had the highest AUC [0.82 (95% confidence interval, 0.69, 0.92)]. The expression of CD11b and HLA-DR was significantly reduced among the septic neonates. Among the cell-surface biomarkers, the maximum AUC was recorded for HLA-DR at 48  [0.68 (95% CI, 0.54, 0.81)]. Comparisons between index tests were not statistically significant.

CONCLUSION

C-reactive protein is superior to other sepsis screen biomarkers and white blood cell-surface biomarkers in diagnosing culture-positive LONS among pre-term infants. CD64, CD11b and HLA DR as diagnostic tests in this group have limited discriminatory value.

LAY SUMMARY

The diagnosis of neonatal blood stream infections is a challenge. In response to bacterial blood stream infections, white blood cells are known to produce an excess of certain types of specialized proteins on their surface, including CD64, CD11b and HLA-DR. In this study we evaluated the concentration of these cell-surface proteins for diagnosing blood stream infections in pre-mature newborn babies, whose onset of infection was beyond 72 h of life. We compared these tests against standard tests that are currently in clinical use, such as C-reactive protein and blood white cell counts. All tests were performed at the time of initially suspecting the infection and 48 h later. The gold standard against which all these tests were evaluated was blood culture, in which the offending bacteria are grown in specialized laboratory media. Of 53 pre-mature babies with suspected infection, 24 had blood culture-proven infection. Among all tests, C-reactive protein at 48 h had the best ability to distinguish definite infection from no infection. The expression of CD11b and HLA-DR was significantly reduced among infected neonates. We conclude that C-reactive protein is superior to white blood cell-surface proteins and white cell count in diagnosing definite late-onset infections among pre-term infants.

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.

Intensive fever control using a therapeutic normothermia protocol in patients with febrile early septic shock: A randomized feasibility trial and exploration of the immunomodulatory effects

Objectives:

Fever control has been shown to reduce short-term mortality in patients with septic shock. This study aimed to explore the feasibility of early intensive fever control in patients with septic shock and to assess the immunomodulatory effects of this intervention.

Methods:

In this single-center, randomized, open-label trial, febrile patients with septic shock presenting to the emergency department were assigned to either a standard fever control or therapeutic normothermia group. Therapeutic normothermia involved intensive fever control in maintaining normothermia below 37°C. The primary outcome was the feasibility of fever control for 24 h. Secondary outcomes included changes in immunomodulatory biomarkers and adverse events.

Results:

Fifteen patients were enrolled and analyzed. Fever control was comparable in both groups, but significantly more patients in the therapeutic normothermia group experienced shivering (p = 0.007). Both groups demonstrated increased C-reactive protein and unchanged neutrophil chemotaxis and CD11b expression. The therapeutic normothermia group revealed significant decreased IL-6 and IL-10. The standard fever control group significantly expressed increased monocytic human leukocyte antigen. There were no significant differences between the groups in terms of immunomodulation.

Conclusions:

Therapeutic normothermia was feasible in patients with febrile septic shock but was not superior to standard fever control in terms of average body temperature and host defense function. Shivering was more frequent in the therapeutic normothermia group.

Trial registration:

Thai Clinical Trials Registry number: TCTR20160321001

Amniotic fluid CD11b levels in pregnancies complicated by preterm prelabor rupture of membranes

Objective: CD11b is an integrin molecule located on the surface of leukocytes. CD11b is involved in the processes of cell adhesion and migration. Expression of CD11b increases during inflammation. Therefore, this study was aimed at the evaluation of concentrations of CD11b in the amniotic fluid from pregnancies complicated by preterm prelabor rupture of the membranes (PPROM), with respect to the presence of microbial invasion of the amniotic cavity (MIAC), intra-amniotic inflammation (IAI), and microbial-associated IAI (the presence of both MIAC and IAI).Methods: Eighty women with singleton pregnancies complicated by PPROM were included. Amniotic fluid samples were obtained by transabdominal amniocentesis. Amniotic fluid CD11b concentrations were determined by enzyme-linked immunosorbent assay. MIAC was determined by a non-cultivation approach. IAI was defined by a bedside amniotic fluid interleukin-6 concentration ≥745 pg/mL.Result: Women with MIAC or microbial-associated IAI had higher CD11b concentrations in the amniotic fluid than women without these complications (with MIAC: median 0.31 ng/mL versus without MIAC: median 0.17 ng/mL, p = .001; with microbial associated-IAI: median 0.35 ng/mL versus without microbial-associated IAI: median 0.16 ng/mL; p =.02). The presence of IAI was not associated with elevated CD11b concentrations. A weak negative correlation was found between amniotic fluid CD11b concentrations and interleukin-6 concentrations (rho = 0.26; p = .02).Conclusions: MIAC and microbial-associated IAI are characterized by higher amniotic fluid CD11b concentrations in pregnancies complicated by PPROM.

Association between Tumor Necrosis Factor-α Promoter -308 G/A Polymorphism and Early Onset Sepsis in Preterm Infants

Early-onset neonatal sepsis (EOS) is diagnosed during the first 7 days of neonatal life and is the major cause of morbidity and mortality among preterm infants. Genetic predisposition may have an impact on EOS susceptibility and outcome. The aim of our study was to explore the association between TNF-α -308 G/A or IL-6 -174 G/C gene polymorphism and the susceptibility and outcome of EOS in preterm infants. The study included 471 preterm infants: 282 with EOS (151 with culture proven sepsis and 131 with clinical sepsis) and 189 without infection (control group). TNF-α -308 G/A and IL-6 -174 G/C were genotyped using Real-time RCR method. We observed significantly higher frequency of A allele of TNF-α -308 G/A polymorphism in blood culture proven EOS (p = 0.017) or clinical EOS (p = 0.025) compared with the control group. Logistic regression confirmed significant association between TNF-α -308 GA+AA genotypes and development of culture proven EOS (B = -0.718, p = 0.013) or clinical EOS (B = -0.602, p = 0.027). No significant differences in IL6 -174G/C alleles or genotypes distribution have been observed between culture proven EOS group, clinical EOS group and the control group. An association between TNF-α -308 G/A or IL-6 -174 G/C genotypes and EOS lethal outcome was not observed (p = 0.652 and p = 0.384, respectively). According to our analysis of large cohort of preterm infants with clearly defined EOS groups, the TNF-α -308 A allele may be a risk factor for the EOS occurrence.

Is neutrophil CD11b a special marker for the early diagnosis of sepsis in neonates? A systematic review and meta-analysis

OBJECTIVES

Our study aimed to synthesise and analyse the early diagnostic value of neutrophil CD11b (nCD11b) for neonatal sepsis.

DESIGN

Systematic review and meta-analysis.

METHODS

Pubmed, Embase, the Cochrane Library and Web of Science Databases were searched up to June 2018. We used Stata software (V.14.0) to conduct the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic OR (DOR), pretest probability, post-test probability and summary receiver operating characteristic (SROC) curve for diagnostic efficiency of n CD11b.

RESULTS

Nine studies, accounting for 843 neonates, were included. The overall pooled sensitivity, specificity, PLR, NLR, DOR, post-test positive probability and post-test negative probability and the area under the SROC curve were 0.82 (95% CI 0.71 to 0.90), 0.93 (95% CI 0.62 to 0.99), 11.51 (95% CI 1.55 to 85.62), 0.19 (95% CI 0.10 to 0.36), 59.50 (95% CI 4.65 to 761.58), 74%, 5% and 0.90, which had accuracy in diagnosing neonatal sepsis.

CONCLUSION

The present evidence indicated that nCD11b is a promising biomarker for the early diagnosis of neonatal sepsis.

Pancreas of coxsackievirus-infected dams and their challenged pups: A complex issue

Enteroviral infections are frequent, often asymptomatic in humans and during gravidity.

The present study is an extension of our previous investigations where we had shown pancreatitis in challenged pups of CVB4-E2-infected dams. Present investigation describes the effect of gestational infection with this virus on the pancreas of both dams and their challenged pups. Gravid CD1 outbred mice were orally infected with CVB4-E2 virus at different gestation times. Pups were challenged orally with the same virus after 25 days of birth. Organs were collected at selected intervals postinfection (p.i.), and replicating virus and viral-RNA copies were analyzed. Additional readouts included histopathology and immunohistochemical (IHC) analysis for localization and identification of Ly6G+ cells (neutrophils), CD11b+ cells (macrophages), and viral protein in pancreatic tissue sections of the infected dams and their challenged pups. Our results show the presence of replicating virus in the pancreas of infected dams and their challenged pups, with inflammation leading to chronic necrotizing pancreatitis and atrophy of pancreatic acini of the dams and their offspring. IHC analysis of the infiltrating cells showed pronounced Ly6G+ neutrophils in dams only, whereas CD11b+ macrophages were present in tissues of both, the pups and the dams. Time of infection during gravidity as well as the p.i. intervals when mice were sacrificed influenced the pancreatic pathophysiology in both groups. We conclude that coxsackievirus infection during pregnancy is a risk factor for chronic affliction of the exocrine tissue and could affect endocrine pancreas in the mother and child.

Pediatric Intensive Care: Immunomodulation With Activated Protein C ex vivo

Objective: Sepsis is major cause of morbidity and mortality in the Pediatric Intensive Care Unit (PICU). PICU patients may develop transient immune deficiency during sepsis. Activated Protein C (APC) has significant anti-inflammatory and cytoprotective effects. Clinical trials of APC in adult sepsis initially showed improved outcome but recent trials showed no benefit in adults or children. We aimed to assess the effects of APC treatment on innate immune responses in children. Design and Subjects: We compared neutrophil and monocyte responses to lipopolysaccharide (LPS) with and without APC treatment in PICU patients at the time of evaluation for sepsis compared with healthy adults and age-matched pediatric controls. We used flow cytometry to examine cell activation (CD11b expression), function [intracellular reactive oxygen intermediate (ROI) release] and LPS recognition [Toll like Receptor 4 (TLR4) expression]. Results: PICU patients had significantly decreased protein c levels and LPS responses compared with adult and pediatric controls for all parameters. APC reduced LPS-induced neutrophil PICU TLR4 and adult ROI (p < 0.05). PICU non-survivors had increased LPS induced neutrophil and monocyte ROI production vs. survivors which was significantly reduced by APC. Conclusion: PICU patients demonstrate significantly reduced endotoxin reactivity which may predispose them to sepsis and alter effective antibacterial responses. APC reduces LPS-induced ROI production in adults and may have a role in treating severely compromised PICU patients especially given that newer APC forms are associated with decreased bleeding risk and enhanced anti-inflammatory effects.

Leptospira species promote a pro-inflammatory phenotype in human neutrophils

Leptospirosis is a global zoonosis caused by pathogenic Leptospira. Neutrophils are key cells against bacterial pathogens but can also contribute to tissue damage. Because the information regarding the role of human neutrophils in leptospirosis is scant, we comparatively analysed the human neutrophil's response to saprophytic Leptospira biflexa serovar Patoc (Patoc) and the pathogenic Leptospira interrogans serovar Copenhageni (LIC). Both species triggered neutrophil responses involved in migration, including the upregulation of CD11b expression, adhesion to collagen, and the release of IL-8. In addition, both species increased levels of pro-inflammatory IL-1β and IL-6 associated with the inflammasome and NFκB pathway activation and delayed neutrophil apoptosis. LIC was observed on the neutrophil surface and not phagocytized. In contrast, Patoc generated intracellular ROS associated with its uptake. Neutrophils express the TYRO3, AXL, and MER receptor protein tyrosine kinases (TAM), but only LIC selectively increased the level of AXL. TLR2 but not TLR4-blocking antibodies abrogated the IL-8 secretion triggered by both Leptospira species. In summary, we demonstrate that Leptospira species trigger a robust neutrophil activation and pro-inflammatory response. These findings may be useful to find new diagnostic markers and therapeutic strategies against leptospirosis.

The value of serum procalcitonin in acute meningitis in children

Early diagnosis and initial therapy are important to reduce the complications of bacterial meningitis. We aimed to evaluate the diagnostic value of serum procalcitonin in children with acute meningitis. We included 40 children (4 months-14 years) suspected to have acute meningitis in our study. Based on the clinical scenario, physical examination and complete analysis of cerebrospinal fluid, patients were assigned into two groups: bacterial meningitis group (24 patients) and aseptic meningitis group (16 patients). Twenty-five apparently healthy children of matched age and sex served as a control group. Procalcitonin, C-reactive protein, and leukocyte count were measured initially at the time of admission and again after 72 h. Initially, patients with bacterial meningitis showed statistically significant higher values of serum procalcitonin than both patients with aseptic meningitis and the control groups (p < 0.001). After 72 h of treatment, patients of bacterial meningitis group showed statistically significant lower values of serum procalcitonin than their initial values (P < 0.05). The cutoff point of procalcitonin needed for early diagnosis of bacterial meningitis was >10 ng/ml at the time of admission. However, values of procalcitonin >2 ng/ml had 100% sensitivity. Whereas, the specificity, negative predictive value and positive predictive value of procalcitonin were 63%, 100%, and 67% respectively. Serum Procalcitonin can be used as an early diagnostic marker of acute bacterial meningitis and its differentiation from aseptic meningitis. In acute bacterial meningitis, it can be used to follow the response to antibiotic therapy.

Biomarkers for diagnosis of neonatal sepsis: a literature review

Sepsis is an important cause of mortality and morbidity in neonatal populations. There has been constant search of an ideal sepsis biomarker that have high sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), so that both the diagnosis and exclusion of neonatal sepsis can be made at the earliest possible and appropriate antibiotics can be started to neonate. Ideal sepsis biomarker will help in guiding us when not to start antibiotics in case of suspect sepsis and total duration of antibiotics course in case of proven sepsis. There are numerous sepsis biomarkers that have been evaluated for early detection of neonatal sepsis but till date there is no single ideal biomarker that fulfills all essential criteria's for being an ideal biomarker. The most commonly used biomarkers are C-reactive protein (CRP) and procalcitonin (PCT), but both have shown varied sensitivity, specificity, PPV and NPV in different studies. We conducted literature search for various neonatal sepsis biomarkers and this review article will cover briefly all the markers with current available evidence.

Neutrophil Receptor Response to Bacterial N-formyl Peptides is Similar in Term Newborn Infants and Adults in Contrast to IL-8

We have previously observed that neutrophils from neonates exhibit different migratory responses to intermediate and end-target chemoattractants compared to adults. The aim of this study was to investigate the effect of the chemoattractants IL-8 (intermediate) and formyl-methionyl-leucyl-phenylalanine (fMLP; end-target) on cell surface receptor expression involved in adhesion, migration and granule release of neutrophils from term newborn infants and adults. Heparinized cord blood from 16 healthy term newborn infants delivered by caesarean section and peripheral blood from 17 healthy adults were incubated with 1 μm IL-8 or 0.1 μm fMLP, previously defined as optimal inducers of neutrophil migration. The leukocytes were labelled with antibodies to cell surface receptors (CD11b, CD15S, CD18, CD35, CD44, CD64, CD65, CD88, CD162, CD181 and CD182). Receptor expression was quantified by flow cytometry analysis. Upregulation of CD11b and downregulation of CD88 and CD182 after stimulation with IL-8 were more pronounced in adults than in neonates (P < 0.05, P < 0.05 and P ≤ 0.001, respectively), whereas fMLP induced changes in receptor expression that were of the same magnitude in neutrophils from neonates as from adults. We observed similar expression of receptors that mediate adhesion, migration, granule activation and phagocytosis induced by fMLP in neutrophils from neonates and adults. In contrast, differences between neonates and adults, induced by IL-8, suggest that the neutrophil response to intermediate chemoattractants might lead to a compromised infectious response in newborn infants.

Increased EMR2 expression on neutrophils correlates with disease severity and predicts overall mortality in cirrhotic patients

Patients with liver cirrhosis are susceptible to infections with high short-term mortalities. One CD97-related EGF-TM7 molecule, EMR2 (EGF-like molecule containing mucin-like hormone receptor 2), had been shown to regulate human neutrophil function, potentiate systemic inflammation. Nevertheless, EMR2 could also suppress neutrophil survival. Studying the role of EMR2 on neutrophil would be intriguing. 48 healthy volunteers and 100 cirrhotic patients were enrolled. Neutrophils were isolated from peripheral blood and cell surface markers were measured by flow cytometry.EMR2 expression levels correlated with CTP scores and increased further in patients with infections. These EMR2-expressed neutrophils were with activated phenotype, but with deranged functions like increased resting oxidative burst and impaired phagocytosis ability. Ligation of EMR2 could increase the phagoburst capacity but not the phagocytosis ability. Furthermore, neutrophils with higher EMR2 expression were more apoptotic and lost the LPS-induced neutrophil survival. Finally, EMR2 expressions on neutrophils correlated with infections and their levels greater than 25 had an AUC = 0.708 for predicting mortality. In conclusion, EMR2 expression levels correlated with CTP scores and increased further in cirrhotic patients with infections. These high EMR2-expressed neutrophils had activated phenotype but with deranged functions. Higher levels of these EMR2-expressed neutrophils correlated with infectious complications and predict mortality.

Early and Late Infections in Newborns: Where Do We Stand? A Review

Neonatal sepsis still represents an important cause of mortality and morbidity among infants. According to the onset, we can distinguish "early onset sepsis" when microbiological cultures positive for external pathogens come from newborns during the first 7 days of life (maternal intrapartum transmission); "late onset sepsis" when microbiological cultures positive for external pathogens come from newborns after the first 7 days from delivery (postnatal acquisition). In this review we synthesize the incidence, risk factors, clinical manifestations, and methods of diagnosis and treatment of each type of neonatal infection, in order to better define such a pathological condition which is of great importance in common clinical practice.

Early detection of neonatal group B streptococcus sepsis and the possible diagnostic utility of IL-6, IL-8, and CD11b in a human umbilical cord blood in vitro model

Background

Group B streptococcus (GBS) infection remains a major cause of neonatal morbidity and mortality, and GBS III is the predominant strain in early-onset GBS neonatal sepsis. To avoid both over- and undertreatment of infants with nonspecific signs of infection, early diagnostic tools are warranted. The aim of this study was to identify biomarkers with high sensitivity and specificity in an early stage of GBS infection. A secondary aim was to assess the utility of a human umbilical cord blood (HUCB) model system of early-onset neonatal sepsis.

Methods

Umbilical cord blood samples from 20 healthy term pregnancies were stimulated for 2 hours with a GBS III isolate from a patient and a commercially available GBS Ia strain. Nonstimulated samples served as controls. Leukocyte surface markers (CD11b, CD64, toll-like receptor [TLR] 2, TLR4, and TLR6) were analyzed by flow cytometry and soluble biomarkers by enzyme-linked immunosorbent assay (interleukin [IL]-6 and -8; interferon-γ-inducing protein [IP]-10; and S100b). The area under the receiver operating characteristic curve (AUC) was calculated for the markers.

Results

GBS III gave the highest responses and AUC values for all biomarkers. Only IL-6 and IL-8 displayed an AUC approaching 0.8 for both GBS serotypes (P<0.001). IL-8 >5,292 pg/mL had both a sensitivity and a specificity of 1.00. IL-6 >197 pg/mL had both a sensitivity and a specificity of 0.95 for GBS III stimulation. CD11b on granulocytes and monocytes was the leukocyte surface marker with the highest AUC values for both GBS serotypes.

Conclusion

In agreement with previous studies, IL-6, IL-8, and potentially CD11b could be useful in diagnosing neonatal GBS infection in an early stage. Our HUCB early-onset neonatal sepsis model may be useful for evaluating biomarkers of neonatal sepsis. The HUCB of neonates with risk factors for sepsis might even be used for diagnostic purposes, but requires further study.

The role of serum procalcitonin in the diagnosis of bacterial meningitis in adults: a systematic review and meta-analysis

OBJECTIVE

Clinically, it is often difficult to differentiate between bacterial and viral aetiologies in adults with suspected meningitis. Several studies have demonstrated the potential use of serum procalcitonin (PCT) in making this differentiation. The aim was to pool these studies into a meta-analysis to determine the diagnostic accuracy of PCT.

METHODS

Major electronic databases were searched for articles studying the use of serum PCT in the differentiation of bacterial and viral meningitis in adult patients. No date or language restrictions were applied. Data analysis was performed using Meta-DiSc 1.4 and MIX 2.0.

RESULTS

Nine studies (n=725 patients) were included in the meta-analysis. Serum PCT was found to be a highly accurate test for diagnosing meningitis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio (DOR) for PCT were 0.90 (95% confidence interval (CI) 0.84-0.94), 0.98 (95% CI 0.97-0.99), 27.3 (95% CI 8.2-91.1), 0.13 (95% CI 0.07-0.26), and 287.0 (95% CI 58.5-1409.0), respectively. PCT was found to be far superior to C-reactive protein, which had a pooled DOR of only 22.1 (95% CI 12.7-38.3).

CONCLUSIONS

Serum PCT is a highly accurate diagnostic test that can be used by physicians for rapid differentiation between bacterial and viral causes of meningitis in adults.

Diagnostic utility of biomarkers for neonatal sepsis--a systematic review

Neonatal sepsis is a major cause of morbidity and mortality. Early diagnosis and treatment of the neonate with suspected sepsis are essential to prevent life-threatening complications. Diagnosis of neonatal sepsis is a challenge due to non-specific clinical signs and the fact that infection markers are difficult to interpret in the first and critical phase of neonatal sepsis. The objective of the present study was to systematically evaluate existing evidence of the diagnostic utility of biomarkers for prediction of sepsis in neonates. We conducted a systematic literature search performed in PubMed and Embase. The study population was neonates with gestation age > 24 weeks in their first 28 days of life with suspected sepsis. The included manuscripts were rated due to criteria from a modified rating scale developed by Douglas Altman. Of 292 potentially relevant manuscripts, 77 fulfilled the inclusion and exclusion criteria; 16 (21%) were rated as high-quality studies. C-reactive protein (CRP) was the most extensively studied biomarker evaluated. The high-quality studies indicated that the acute phase protein serum amyloid A had high sensitivity, both at onset of symptoms and 2 days after. The studies evaluating serum amyloid A presented a variable positive predictive value (PPV, 0.67 and 0.92) with a high negative predictive value (NPV, 0.97 and 1.00). The existing evidence of the diagnostic value of serum amyloid A for neonatal sepsis showed promising results, and should be further investigated in clinical settings.

Diagnostic utility of neutrophil CD64 as a marker for early-onset sepsis in preterm neonates

Introduction

Neutrophil CD64 has been proposed as an early marker of sepsis. This study aims to evaluate the diagnostic utility of neutrophil CD64 for identification of early-onset sepsis in preterm neonates.

Methods

The prospective study was conducted in a neonatal intensive care unit between November 2010 and June 2011. Preterm neonates in whom infection was suspected when they were <12 hours of age were enrolled. Complete blood count with differential, blood culture, neutrophil CD11b and CD64 measurement were performed. Receiver operating characteristic curve analysis was performed to evaluate the performance of neutrophil CD64 as biomarker of sepsis.

Results

A total of 158 preterm neonates was enrolled, 88 of whom were suspected infection. The suspected sepsis group was of lesser gestational age (P<0.001) and lower birth weight (P<0.001), compared with controls. The hematologic profiles of the suspected sepsis group were characterized by higher white blood cell count, neutrophil counts and C-reactive protein. The suspected sepsis neonates had significantly higher neutrophil CD64 expression compared with controls. Neutrophil CD64 had an area value under the curve of 0.869 with an optimal cutoff values of 1010 phycoerythrin molecules bound/cell and it had a high sensitivity (81.82%) and negative predictive value (77.4%). The level of neutrophil CD64 was independent of antibiotic therapy within 24 hours after the onset of sepsis in preterm neonates.

Conclusions

Neutrophil CD64 is a highly sensitive marker for suspected early-onset sepsis in preterm neonates. Our study suggests that neutrophil CD64 may be incorporated as a valuable marker to diagnose infection.

Time for a neonatal-specific consensus definition for sepsis

OBJECTIVE

To review the accuracy of the pediatric consensus definition of sepsis in term neonates and to determine the definition of neonatal sepsis used.

STUDY SELECTION

The review focused primarily on pediatric literature relevant to the topic of interest.

CONCLUSIONS

Neonatal sepsis is variably defined based on a number of clinical and laboratory criteria that make the study of this common and devastating condition very difficult. Diagnostic challenges and uncertain disease epidemiology necessarily result from a variable definition of disease. In 2005, intensivists caring for children recognized that as new drugs became available, children would be increasingly studied and thus, pediatric-specific consensus definitions were needed. Pediatric sepsis criteria are not accurate for term neonates and have not been examined in preterm neonates for whom the developmental stage influences aberrations associated with host immune response. Thus, specific consensus definitions for both term and preterm neonates are needed. Such definitions are critical for the interpretation of observational studies, future training of scientists and practitioners, and implementation of clinical trials in neonates.

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.

CD15s is a potential biomarker of serious bacterial infection in infants admitted to hospital

Early recognition of serious bacterial infection (SBI) in children is essential for better treatment outcome. Flow cytometry analysis of neutrophil surface molecules has been more frequently utilized as a tool for diagnosis of infection. The infants (n = 105) under 6 months of age presenting to the pediatric emergency department with fever without apparent source who were hospitalized with suspicion of having SBI were enrolled in this prospective study. Sixty-nine infants were included into the training pool and were classified into bacterial or viral infection group. Validation pool consisted of 36 infants. The values of white blood cells counts, absolute neutrophil count (ANC), C-reactive protein (CRP), procalcitonin (PCT), neutrophil CD11b, CD15s and CD64 expression, and the percentage (%CD15s+) and absolute count (AC-CD15s+) of CD15s+ neutrophils were determined. In infants with SBI, %CD15s+ was 10.5 times more likely to be higher than the cut-off value. ANC, CRP, PCT, CD64, and AC-CD15s+ were also found as useful biomarkers for differentiation between bacterial and viral infection. The best fit multivariate logistic regression model included CRP, PCT, and %CD15s+ as strong predictors of SBI. The model's sensitivity (87 %) and specificity (83 %) indicated high model's accuracy. After validation on independent dataset, model's accuracy maintained high: 86 % sensitivity and 93 % specificity, confirming its reliability and supporting CRP, PCT, and %CD15s+ as real predictors. The findings of this study support assumption made in the literature on significance of CD15s in inflammation processes. Also, this study demonstrated for the first time that CD15s is potentially valuable biomarker of SBI in infants.

In vivo effect of recombinant human granulocyte colony-stimulating factor on neutrophilic expression of CD11b in septic neonates: a randomized controlled trial

Neonates are susceptible to septicemia secondary to quantitative and qualitative neutrophilic defects. Granulocyte colony-stimulating factor (G-CSF) stimulates myeloid progenitor cell proliferation and induces selective neutrophil functions. The authors aimed to evaluate the effect of G-CSF administration in septic neonates on neutrophil production and CD11b expression. Sixty septic neonates were randomized to receive intravenous G-CSF 10 μg/kg/day for 3 days (G-CSF group, n = 30), or not to receive G-CSF (non-G-CSF group, n = 30). Thirty healthy newborns were included as controls. Laboratory investigations included complete blood count, C-reactive protein, blood culture, renal and liver function tests, and assessment of neutrophilic expression of CD11b. Total leukocytes count (TLC), absolute neutrophil count (ANC), and immature myeloid cell count in G-CSF group showed significant difference between post-and pre-G-CSF levels. TLC, ANC, immature myeloid cell count and immature/total myeloid cells ratio were higher in G-CSF group compared to non-G-CSF group on days 1 and 3. Higher neutrophilic expression of CD11b was reported in both septic groups on day 0 compared to control group. On day 5, CD11b was higher in G-CSF group than non-G-CSF group. G-CSF improved CD11b% in neutropenic and non-neutropenic septic neonates. No significant difference was found between pre- and posttreatment renal and liver function tests. Lower duration of antibiotic intake and hospitalization was observed in G-CSF group compared to non-G-CSF group. G-CSF administration as an adjuvant therapy for neonatal septicemia, whether neutropenic or not, improves neutrophilic count and function and contributed to early healing from sepsis.

Evaluation of adhesion molecules CD64, CD11b and CD62L in neutrophils and monocytes of peripheral blood for early diagnosis of neonatal infection

BACKGROUND

This study was undertaken to assess the value of neutrophils CD11b, CD64, and CD62L for the early diagnosis of neonatal infection.

METHODS

Eighty-four neonates who were followed up for a suspected neonatal infection were included in this study. They were assigned into an infection group (n=49) and a non-infection group (n=35). Healthy neonates served as controls (n=35). A full sepsis screening was performed and neutrophil and monocyte expressions of CD11b, CD64 and CD62L were determined by flow cytometry.

RESULTS

The expressions of CD64 and CD11b were significantly enhanced in the infection group compared to the non-infective group and the controls.

CONCLUSIONS

CD64 expression on neutrophils and monocytes is a useful diagnostic marker for the early diagnosis of neonatal infection. Combination of CD64, CD11b and C reactive protein further enhances the sensitivity of the expression and its negative predictive value.

Analysis of the temperature affects on leukocyte surface antigen expression

Flow cytometric analysis of leukocyte surface antigens has been used to characterize infectious and septic processes in patients. We wanted to investigate how the sampling and processing temperature, the anticoagulant used, and the storage of the sample influence leukocyte immunophenotyping. Four blood samples, two using acid citrate dextrose and two using heparin as an anticoagulant, were taken from five intensive-care unit patients with severe sepsis and five healthy volunteers. The samples were collected, stored, and processed either at +4°C or at room temperature (RT). The samples were processed for flow cytometric analysis within 1  hr of collection or after 6 or 24  hr storage. The surface antigens of interest were neutrophilic CD11b and CD64, monocytic CD11b, CD14, CD40, CD64, CD80 and HLA-DR, and lymphocytic CD69 (separately in CD4+ and CD8+ T cells, B cells, and natural killer cells). The fluorescence intensities were higher at RT than at +4°C. During storage the intensities increased at RT, but at +4°C there were only minor changes. The effects were similar with both anticoagulants studied. According to our results, flow cytometric analysis of leukocyte surface antigen expressions should be performed using +4°C temperature throughout the process and within 6  hr.

Serum procalcitonin in viral and bacterial meningitis

Background:

In children with meningitis, there is a difficulty to verify the etiology as viral or bacterial. Therefore, intensive research has been carried out to find new and rapid diagnostic methods for differentiating bacterial from viral meningitis.

Objectives:

The aim of this work was to study the behavior of procalcitonin (PCT) and whether it can be used to differentiate children with bacterial from those with viral meningitis. We also compared PCT to C-reactive protein (CRP) and white blood cell count.

Patients and Methods:

Forty children aged from 4 months to 12 years with clinically suspected meningitis were studied. Lumbar punctures were done for all cases before starting initial antibiotic treatment. According to the results of bacterial cultures and cerebrospinal fluid (CSF) cytochemical profile, our patients were classified into two groups: bacterial meningitis group and viral meningitis group. PCT, CRP, and leukocyte count were measured at the time of admission and after 3 days.

Methods:

Forty children aged from 4 months to 12 years with clinically suspected meningitis were studied. Lumbar punctures were done for all cases before starting initial antibiotic treatment. According to the results of bacterial cultures and cerebrospinal fluid (CSF) cytochemical profile, our patients were classified into two groups: bacterial meningitis group and viral meningitis group. PCT, CRP, and leukocyte count were measured at the time of admission and after 3 days.

Results:

PCT levels were significantly higher in patients with bacterial meningitis (mean, 24.8 ng/ml) compared to patients with viral meningitis (mean, 0.3 ng/ml) (P<0.001). PCT levels in bacterial meningitis group decreased after 3 days of starting treatment, but remained higher than viral meningitis group (mean, 10.5 ng/ml). All CSF parameters, blood leukocytes, and CRP showed overlapping values between the two groups. Serum PCT with cut off value >2 ng/ml showed sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 66%, 68%, and 100%, respectively, for the diagnosis of bacterial meningitis.

Conclusion:

Serum procalcitonin level has a better diagnostic and prognostic value than CRP or leukocyte count to distinguish between bacterial and viral meningitis. It is also a good indicator of the efficacy of treatment of bacterial meningitis.

Biomarkers for late-onset neonatal sepsis: cytokines and beyond

Acute phase reactants, pro and antiinflammatory mediators including chemokines and cytokines, and cell-surface antigens are nonspecific biomarkers that have been extensively studied for the diagnosis and management of late-onset neonatal sepsis (LONS) and necrotizing enterocolitis. It is expected that the next generation of biomarkers and tests will be more specific, will pinpoint the precise disease entity, and will provide crucial information on the exact pathogen or category of microorganism and its antibiotic profile within hours of clinical presentation. Research on molecular pathogen detection and proteomic profiling has shown promising results. Academic-industry partnerships are vital for successful development of new diagnostic biomarkers for LONS, which are sensitive, inexpensive, fully automated, and easy to measure, allowing a quick turnaround time for clinical decision making.

Surfactant protein-d inhibits lung inflammation caused by ventilation in premature newborn lambs

RATIONALE

Premature newborns frequently require manual ventilation for resuscitation during which lung injury occurs. Although surfactant protein (SP)-D regulates pulmonary inflammation, SP-D levels are low in the preterm lung. Commercial surfactants for treatment of respiratory distress syndrome do not contain SP-D.

OBJECTIVES

To determine whether addition of recombinant human SP-D (rhSP-D) to commercial surfactant influences lung inflammation in ventilated premature newborn lambs.

METHODS

Prematurely delivered lambs (130 d gestation age) were resuscitated with 100% O(2) and peak inspiratory pressure 40 cm H(2)O for 20 minutes and then treated with Survanta or Survanta containing rhSP-D. Ventilation was then changed to regulate tidal volume at 8 to 9 ml/kg. At 5 hours of age lambs were killed for sample collection.

MEASUREMENTS AND MAIN RESULTS

Sequential blood gas and tidal volume were similar in lambs treated with or without rhSP-D, indicating that lung immaturity and ventilatory stress used to support premature lambs were comparable between the two groups. Ventilation caused pulmonary inflammation in lambs treated with surfactant alone. In contrast, surfactant containing rhSP-D decreased neutrophil numbers in bronchoalveolar lavage fluid and decreased neutrophil elastase activity in lung tissue. IL-8 mRNA and IL-8 protein were significantly decreased in the +rhSP-D group lamb lungs, to 20% of those in controls. The addition of rhSP-D also rendered Survanta more resistant to plasma protein inhibition of surfactant function.

CONCLUSIONS

Treatment with rhSP-D-containing surfactant inhibited lung inflammation and enhanced the resistance of surfactant to inhibition, supporting its potential usefulness for prevention of lung injury in the preterm newborn.

Neutrophil CD64 (FcγRI) expression is a specific marker of bacterial infection: A study on the kinetics and the impact of major surgery

Neutrophil CD64 expression is a diagnostic marker for the early detection of bacterial infections. The aim was to investigate the kinetics of neutrophil CD64 expression during bacterial infection and the possible impact of surgical trauma. Blood samples were collected daily during 3 d after admission for analysis by flow cytometry of the surface expressions on neutrophils and monocytes of CD64, CD16, CD32, CD11b/CD18 and CD35, and analysis of serum CRP and blood WBC. Serum concentrations of IFNgamma, G-CSF, IL-6 and IL-8 were also analysed in adults. Eight children and 19 adult patients with bacterial infections, 12 patients admitted for hip-arthroplasty because of coxarthrosis and 30 healthy adults were studied. Neutrophil CD64 was increased all 3 d after start of treatment (p<0.0001) in children and adults with bacterial infections. The postoperative increase after surgery was less than the increase seen during bacterial infections (p<0.0001). CRP, G-CSF, IL-6 and IL-8 were raised both in bacterial infections and after surgery. Our results indicate that the expression of CD64 on neutrophils is a specific sign of bacterial infections. Neutrophil expression of CD64, therefore, seems to be a promising tool for the early detection of bacterial infections even during surgery.

Neutrophil and monocyte receptor expression in uncomplicated and complicated influenza A infection with pneumonia

Following influenza, the elderly and those with chronic heart/lung diseases are often affected by bacterial complications such as pneumonia. Whether neutrophil and monocyte functions are affected differently in patients with or without complications is less well known. Therefore, blood neutrophil and monocyte surface receptor expressions were measured in patients with influenza A, with or without complications, by means of flow cytometry. Neutrophil expressions of the adhesion molecules CD11b and CD66b were increased in influenza A, with the highest expression of CD11b in uncomplicated influenza. Monocyte expressions of CD11b and CD18 were also higher in influenza compared with bacterial infection and healthy controls. Neutrophil expressions of the phagocyte receptors CD64 and CD32 and the complement receptor CD35 were impaired in influenza with and without pneumonia compared with bacterial infection, whereas the expressions in monocytes were increased in all infected groups. The expression of the phagocyte receptor CD16 on neutrophils was impaired in all infected groups. Our results suggest increased recruitment of neutrophils and monocytes to infected areas by up-regulation of adhesion molecules in influenza that may be involved in the inflammatory response during infection. In contrast, depression of phagocyte receptor expression on neutrophils in patients with influenza pneumonia may contribute to increased susceptibility to bacterial infections and impaired clearance of encapsulated bacteria such as pneumococci.

Injury enhances resistance to Escherichia coli infection by boosting innate immune system function

Major injury is widely thought to predispose the injured host to opportunistic infections. This idea is supported by animal studies showing that major injury causes reduced resistance to polymicrobial sepsis induced by cecal ligation and puncture. Although cecal ligation and puncture represents a clinically relevant sepsis model, we wanted to test whether injury might also lead to greater susceptibility to peritoneal infection caused by a single common pathogen, Escherichia coli. Contrary to our expectation, we show herein that the LD(50) for sham-injured mice was 10(3) CFU of E. coli, whereas the LD(50) for burn-injured mice was 50 x 10(3) CFU at 7 days postinjury. This injury-associated enhanced resistance was apparent as early as 1 day after injury, and maximal resistance was observed at days 7 and 14. We found that burn-injured mice had higher numbers of circulating neutrophils and monocytes than did sham mice before infection and that injured mice were able to recruit greater numbers of neutrophils to the site of infection. Moreover, the peritoneal neutrophils in burn-injured mice were more highly activated than neutrophils from sham mice as determined by Mac-1 expression, superoxide generation, and bactericidal activity. Our findings suggest that the enhanced innate immune response that develops following injury, although it is commonly accepted as the mediator of the detrimental systemic inflammatory response syndrome, may also, in some cases, benefit the injured host by boosting innate immune antimicrobial defenses.

Distinction between bacterial and viral infections

PURPOSE OF REVIEW

To commence proper treatment as rapidly as possible and to reduce unnecessary antibiotic treatments, timely knowledge of whether the infection is bacterial or viral in origin would be beneficial for the clinician. As a reliable prediction of the causative agent of bacterial infection is not possible based on clinical features, there is an ongoing need for sensitive and specific markers of bacterial infection.

RECENT FINDINGS

The most common differential diagnosis methods are reviewed here. It is also demonstrated that the measurement of the expression of complement receptors, particularly CR1 (CD35), on neutrophils can be a useful preliminary test to differentiate between bacterial and viral infections. In addition, a novel marker of local and systemic bacterial infections designated 'clinical infection score (CIS) point', which incorporates quantitative analysis of complement receptors on neutrophils and standard clinical laboratory data and displays 98% sensitivity and 97% specificity in distinguishing between bacterial and viral infections, is presented.

SUMMARY

We conclude that the diagnostic yield of measured individual variables in distinguishing between bacterial and viral infections increases upon combination.

Biomarkers in neonatal infection

Infected newborn infants are often difficult to differentiate from patients suffering from noninfective diseases. Whilst delaying treatment with antibiotics of infected infants may be fatal, widespread indiscriminate use in all cases with suspected bacterial infection could lead to both drug-induced complications and the development of multidrug-resistant organisms. Conventional biomarkers, such as blood cell counts and morphology, have serious limitations. Investigators in this area of research have, therefore, made strenuous efforts to discover more reliable biomarkers with superior diagnostic utilities and clinically relevant characteristics to help neonatal clinicians differentiate between infected and noninfected infants. The major classes of biomarkers in neonatal infection of recent interest will be discussed, including: acute phase reactants, cytokines, chemokines and leukocyte surface antigens. The application of these biomarkers to derive prognostic information useful to neonatal clinicians will also be considered.

Newer approaches to the diagnosis of early onset neonatal sepsis

Accurate and timely diagnosis of early onset neonatal sepsis remains challenging to the clinician and the laboratory. A test with a rapid turnaround time with 100% sensitivity, rather than high specificity, which allows accurate diagnosis and appropriate antimicrobial treatment or which allows antibiotics to be safely withheld in non-infected infants, is desirable. Many potential markers (acute phase reactants, cell surface markers, cytokines) are not routinely available to the laboratory, and most likely combinations of markers will ensure greater diagnostic accuracy. In the future, molecular biology techniques offer the prospect of rapid identification of both pathogens and antimicrobial resistance markers.

Quantitative Measurement of Monocyte HLA-DR Expression in the Identification of Early-Onset Neonatal Infection

BACKGROUND

This study aimed to evaluate the diagnostic utilities of monocyte HLA-DR as an infection marker in the identification of early-onset clinical infection and pneumonia in newborn infants.

METHODS

Term newborns in whom infection was suspected when they were <72 h of age were eligible for enrollment in the study. C-reactive protein (CRP), monocyte HLA-DR and neutrophil CD64 expressions were quantitatively measured at the time of sepsis evaluation (0 h) and 24 h afterwards by flow cytometry and standard laboratory method.

RESULTS

A total of 288 infants with suspected sepsis were investigated, and 93 were found to be clinically infected. There were no significant differences in monocyte HLA-DR expression between the infected, non-infected and control groups at 0 h (median (interquartile range): 13,986 (10,994-18,544), 14,234 (12,045-17,474) and 18,441 (14,250-21,537) antibody phycoerythrin (PE) molecules bound/cell), and between infected and non-infected infants at 24 h (median (interquartile range): 17,772 (12,933-25,167) and 19,406 (14,885-24,225) antibody PE molecules bound/cell). The areas under the receiver operating characteristics (ROC) curves for HLA-DR, CD64 and CRP were 0.52-0.54, 0.88-0.94 and 0.75-0.77, respectively. We were unable to determine an optimal cutoff value for HLA-DR, as the diagnostic utilities of any cutoff point on the ROC curves were unable to satisfy the criteria (i.e. sensitivity and specificity >or=80%) for consideration as an useful diagnostic marker of infection.

CONCLUSIONS

Our findings did not support the use of monocyte HLA-DR alone or in combination with other infection markers in the diagnosis of early-onset clinical infection and pneumonia in term newborns.

Onset of mechanical ventilation is associated with rapid activation of circulating phagocytes in preterm infants

OBJECTIVE

In preterm infants with respiratory distress syndrome (RDS), circulating neutrophils are activated. Kinetics and effects of surfactant therapy on this activation are unknown. Therefore, we studied activation of circulating neutrophils and monocytes in newborn preterm infants with and without RDS.

PATIENTS AND METHODS

Preterm infants with RDS who were mechanically ventilated and received surfactant ("ventilated infants": n = 38; mean gestational age +/- SD: 28.3 +/- 2.2 weeks; mean birth weight +/- SD: 1086 +/- 353 g) and preterm infants who received nasal continuous positive airway pressure (n = 8) or no ventilatory support (n = 17) ("control infants": mean gestational age +/- SD: 32.1 +/- 1.2 weeks; mean birth weight +/- SD: 1787 +/- 457 g) were recruited. Blood samples were taken from ventilated infants at birth, before surfactant treatment, at 1 and 2 hours after surfactant, and at 12 to 24 hours of age. Blood samples were taken from control infants at birth, at 2 to 6 hours, and at 12 to 24 hours of age. Phagocyte CD11b expression was analyzed by flow cytometry.

RESULTS

In ventilated infants, phagocyte CD11b expression increased from birth to the first postnatal samples. It increased further by 12 to 24 hours of age. Control infants with or without nasal continuous positive airway pressure showed no significant increase after birth. At 12 to 24 hours of age, phagocyte CD11b expression was higher in ventilated infants than in control infants. In ventilated infants, neutrophil CD11b expression at 1 and 2 hours after surfactant correlated positively with gestational age.

CONCLUSIONS

In preterm infants with RDS, significant activation of circulating phagocytes occurs within 1 to 3 hours of the onset of mechanical ventilation, independent of surfactant administration, which indicates that mechanical ventilation may be the inducer of this systemic inflammatory response.

Improved diagnostic approaches to infection/sepsis detection

Sepsis is a major healthcare problem from the perspective of mortality and economics. Advances in diagnostic detection of infection and sepsis have been slow, but recent advances in both soluble biomarker detection and quantitative cellular measurements promise the availability of improved diagnostic techniques. Though the promise of cytokine measurements reaching clinical practice have not matured, procalcitonin levels are currently available in many countries and appear to offer enhanced diagnostic distinction between bacterial and viral etiologies. Cellular diagnostics is poised to enter clinical laboratory practice in the form of neutrophil CD64 measurements, which offer superior sensitivity and specificity to conventional laboratory assessment of sepsis. Neutrophil CD64 expression is negligible in the healthy state. However, it increases as part of the systemic response to severe infection or sepsis. The combination of cellular proteomics, as in the case of neutrophil CD64 quantification, and selected soluble biomarkers of the inflammatory response, such as procalcitonin or triggering receptor expressed on myeloid cells (TREM)-1, is predicted to remove the current subjectivity and uncertainty in the diagnosis and therapeutic monitoring of infection and sepsis.