Lipopolysaccharide-binding protein in critically ill neonates and children with suspected infection: comparison with procalcitonin, interleukin-6, and C-reactive protein

Diagnostic Accuracy of Endotoxin and Endotoxin Binding Protein in Late-Onset Neonatal Sepsis

OBJECTIVES

To evaluate the diagnostic utility of endotoxin and endotoxin binding protein (EBP) for the diagnosis of late-onset neonatal sepsis (LOS) and compare it with the diagnostic utility of C-reactive protein (CRP).

METHODS

This diagnostic study of neonates, both term and preterm, with clinical suspicion of LOS was conducted in a tertiary care institute in India between January 2021 and March 2023. Blood samples were collected for evaluating endotoxin and EBP along with culture. Endotoxin and EBP were measured with enzyme linked immunosorbent assay, CRP was measured by nephelometry method, and the results were compared with blood culture done with BACTEC (gold standard).

RESULTS

Out of 160 samples, 73 showed culture positivity. Endotoxin was positive in 81 samples and showed sensitivity of 84%, specificity of 78% and diagnostic accuracy of 81% (AUC 0.837, P value <0.001). EBP was positive in 82 samples and showed sensitivity of 80.8%, specificity of 73% and diagnostic accuracy of 76% (AUC 0.824, P value <0.001). CRP was positive in 105 samples and had sensitivity of 86%, specificity of 51% and diagnostic accuracy of 67% (AUC 0.827, P value <0.001).

CONCLUSIONS

The present study showed endotoxin and EBP have higher specificity for diagnosing neonatal sepsis. As culture takes minimum 48 h, endotoxin and EBP can be utilized as biomarkers for diagnosis of sepsis.

Advances in sepsis biomarkers

Sepsis, a dysregulated host immune response to an infectious agent, significantly increases morbidity and mortality for hospitalized patients worldwide. This chapter reviews (1) the basic principles of infectious diseases, pathophysiology and current definition of sepsis, (2) established sepsis biomarkers such lactate, procalcitonin and C-reactive protein, (3) novel, newly regulatory-cleared/approved biomarkers, such as assays that evaluate white blood cell properties and immune response molecules, and (4) emerging biomarkers and biomarker panels to highlight future directions and opportunities in the diagnosis and management of sepsis.

Advancement in biomarker based effective diagnosis of neonatal sepsis

Neonatal sepsis is considered as alarming medical emergency and becomes the common global reason of neonatal mortality. Non-specific symptoms and limitations of conventional diagnostic methods for neonatal sepsis mandate fast and reliable method to diagnose disease for point of care application. Recently, disease specific biomarkers have gained interest for rapid diagnosis that led to the development of electrochemical biosensor with enhanced specificity, sensitivity, cost-effectiveness and user-friendliness. Other than conventional biomarker C-reactive protein to diagnose neonatal sepsis, several potential biomarkers including Procalcitonin (PCT), Serum amyloid A (SAA) and other candidates are extensively investigated. The present review provides insights on advancements and diagnostic abilities of protein and nucleotide based biomarkers with their incorporation in developing electrochemical biosensors by employing novel fabrication strategies. This review provides an overview of most promising biomarker and its capability for neonatal sepsis diagnosis to fulfil future demand to develop electrochemical biosensor for point-of-care applications.

Biomarkers Predicting Tissue Pharmacokinetics of Antimicrobials in Sepsis: A Review

The pathophysiology of sepsis alters drug pharmacokinetics, resulting in inadequate drug exposure and target-site concentration. Suboptimal exposure leads to treatment failure and the development of antimicrobial resistance. Therefore, we seek to optimize antimicrobial therapy in sepsis by selecting the right drug and the correct dosage. A prerequisite for achieving this goal is characterization and understanding of the mechanisms of pharmacokinetic alterations. However, most infections take place not in blood but in different body compartments. Since tissue pharmacokinetic assessment is not feasible in daily practice, we need to tailor antibiotic treatment according to the specific patient’s pathophysiological processes. The complex pathophysiology of sepsis and the ineffectiveness of current targeted therapies suggest that treatments guided by biomarkers predicting target-site concentration could provide a new therapeutic strategy. Inflammation, endothelial and coagulation activation markers, and blood flow parameters might be indicators of impaired tissue distribution. Moreover, hepatic and renal dysfunction biomarkers can predict not only drug metabolism and clearance but also drug distribution. Identification of the right biomarkers can direct drug dosing and provide timely feedback on its effectiveness. Therefore, this might decrease antibiotic resistance and the mortality of critically ill patients. This article fills the literature gap by characterizing patient biomarkers that might be used to predict unbound plasma-to-tissue drug distribution in critically ill patients. Although all biomarkers must be clinically evaluated with the ultimate goal of combining them in a clinically feasible scoring system, we support the concept that the appropriate biomarkers could be used to direct targeted antibiotic dosing.

Kawasaki Disease Complicated by Salmonella oranienburg Coinfection

Kawasaki disease is a medium vessel vasculitis with a multisystem presentation affecting 9-20 per 100,000 children under 5 years of age in the United States. Salmonella coinfection has not been previously described. We present a 12-month-old vaccinated male with Kawasaki disease in the setting of Salmonella bacteremia. Initial intervention for the Kawasaki disease with IVIG was ineffective, prompting adjunctive therapy with anakinra, with eventual full recovery. Concurrent Kawasaki disease and bacteremia may confound diagnosis and necessitate nontraditional treatment approaches.

The value of interleukin-6 (IL-6) within 6 hours after birth in the prompt diagnosis of early-onset neonatal sepsis

BACKGROUND

To investigate the value of interleukin-6 (IL-6) for neonates within 6 hours after birth in the prompt diagnosis of early-onset neonatal sepsis (EONS).

METHODS

The clinical and laboratory data of 129 neonates in the neonatal intensive care unit (NICU) of our center from March 31, 2017, to February 29, 2020, were retrospectively analyzed. These patients were divided into two groups on their disease conditions: the EONS group (n=66) and the healthy control group (n=63). All enrolled patients were born in our hospital's Obstetrics Department and were admitted to the NICU within 2 hours after birth. The first session of the blood test was conducted within 4-6 hours after birth for the measurements of IL-6, C-reactive protein (CRP1), serum amyloid A1 (SAA1), and serum immunoglobulin M (IgM). The second session of the blood test was performed 12-24 hours after birth for procalcitonin (PCT), CRP2, and SAA2. All the tests were completed in our clinical laboratory. The non-parametric test (Mann-Whitney U test) was used to compare all parameters between these two groups. The receiver operating characteristic (ROC) curves were drawn to compare the diagnostic sensitivities and specificities. The pairwise comparisons of the ROC curves were on the MedCalc18.2.1 software. A P value of <0.05 was considered statistically significant.

RESULTS

Gender, birth weight, and gestational age were matched between the EONS group and the control group (all P>0.05). The differences of IL-6, CRP2, PCT, and SAA2 were statistically significant between these two groups (all P<0.05), while there was no significant difference in CRP1, SAA1, and IgM (all P>0.05). The area under the ROC curve (AUC) is 1 (95% CI: 0.918-1.000), 1 (95% CI: 0.918-1.000), 1 (95% CI: 0.918-1.000), and 0.977 (95% CI: 0.878-0.999), respectively, for IL-6, CRP2, PCT, and SAA2. Pairwise comparisons among four biomarkers showed the diagnostic specificity and sensitivity of IL-6 were not significantly different from those of CRP2, PCT, and SAA2 (all P>0.05).

CONCLUSIONS

IL-6 is a quick and independent diagnostic biomarker for EONS, and its sensitivity and specificity are inferior to the conventional inflammation markers, including CRP, PCT, and SAA.

Early Inflammatory Markers for the Diagnosis of Late-Onset Sepsis in Neonates: The Nosodiag Study

Background: Early diagnosis is essential to improve the treatment and prognosis of newborn infants with nosocomial bacterial infections. Although cytokines and procalcitonin (PCT) have been evaluated as early inflammatory markers, their diagnostic properties have rarely been compared. Objectives: This study evaluated and compared the ability of individual inflammatory markers available for clinician (PCT, semi-quantitative determination of IL-8) and of combinations of markers (CRPi plus IL-6 or quantitative or semi-quantitative determination of IL-8) to diagnose bacterial nosocomial infections in neonates. Methods: This prospective two-center study included neonates suspected of nosocomial infections from September 2008 to January 2012. Inflammatory markers were measured initially upon suspicion of nosocomial infection, and CRP was again measured 12-24 h later. Newborns were retrospectively classified into two groups: those who were infected (certainly or probably) and uninfected (certainly or probably). Results: The study included 130 infants of median gestational age 28 weeks (range, 24-41 weeks). Of these, 34 were classified as infected and 96 as uninfected. The sensitivity, specificity, positive and negative predictive values (PPV and NPV), and positive and negative likelihood ratios (LR+ and LR-) for PCT were 59.3% (95% confidence interval [CI], 38.8-77.6%), 78.5% (95% CI, 67.8-86.9%), 48.5% (95% CI, 30.8-66.5%), 84.9% (95% CI, 74.6-92.2%), 2.7 (95% CI, 1.6-4.9), and 0.5 (95% CI, 0.3-0.8), respectively. Semi-quantitative IL-8 had the highest specificity (92.19%; 95% CI, 82.70-97.41%), PPV (72.22%; 95% CI, 46.52-90.30%) and LR+ (6.17, 95% CI, 2.67-28.44), but had low specificity (48.15%; 95% CI, 28.67-68.05%). Of all markers tested, the combination of IL-6 and CRPi had the highest sensitivity (78.12%; 95% CI, 60.03-90.72%), NPV (91.3%; 95% CI, 82.38-96.32%) and LR- (0.29; 95% CI, 0.12-0.49). The combination of IL-6 and CRPi had a higher area under the curve than PCT, but with borderline significance (p = 0.055). Conclusions: The combination of IL-6 and CRPi was superior to other methods, including PCT, for the early diagnosis of nosocomial infection in neonates, but was not sufficient for sole use. The semi-quantitative determination of IL-8 had good diagnostic properties but its sensitivity was too low for use in clinical practice.

Proteomics analysis reveals differential pattern of widespread protein expression and novel role of histidine-rich glycoprotein and lipopolysaccharide-binding protein in rheumatoid arthritis

Rheumatoid factor (RF) is an auto-antibody against antigen-antibody immune complexes. RF is valuable as a biomarker for the screening of autoimmune and infectious diseases. However, it is suggested that RF would be a more powerful biomarker when used complementarily with RF-correlated proteins. In this study, we utilized a proteomic approach to analyze global protein expression in RF-low and RF-high subjects using high-performance liquid chromatography tandem mass spectrometry. Histidine-rich glycoprotein (HRG) and lipopolysaccharide-binding protein (LBP) were found to be differentially expressed between RF-low and RF-high subjects (cut-off > 2-fold, p < 0.05), which was validated by enzyme-linked immunosorbent assay. To evaluate whether both proteins allow discriminating rheumatoid arthritis patients from healthy controls, receiver-operating characteristic (ROC) curves were analyzed. Areas under the ROC curves of HRG and LBP were 0.861 and 0.888, respectively. The correlation between RF and HRG was statistically significant (p = 0.003), and LBP was also correlated with RF (p = 0.044), as indicated by correlation analysis. HRG and LBP are reportedly involved in RF-producing and RF-correlated diseases. Thus, we propose that HRG and LBP could be useful screening markers for RF-correlated diseases.

Diagnostics for neonatal sepsis: current approaches and future directions

Progress has been made in the reduction of morbidity and mortality from neonatal sepsis. However, diagnosis continues to rely primarily on conventional microbiologic techniques, which can be inaccurate. The objective of this review is to provide the clinician with an overview of the current information available on diagnosing this condition. We review currently available diagnostic approaches for documenting neonatal sepsis and also describe novel approaches for diagnosing infection in neonates who are under development and investigation. Substantial progress has been made with molecular approaches and further development of non-culture-based methods offer promise. The potential ability to incorporate antimicrobial resistance gene testing in addition to pathogen identification may provide a venue to incorporate a predominantly molecular platform into a larger program of neonatal care.

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.

Clinical impact of interleukin 6 as a predictive biomarker in the early diagnosis of postoperative systemic inflammatory response syndrome after major thoracic surgery: A prospective clinical trial

BACKGROUND

Postoperative systemic inflammatory response syndrome and sepsis are associated with high morbidity and mortality rates. Early detection of postoperative systemic inflammatory response syndrome improves the outcome. The aim of this study was to evaluate the feasibility of interleukin 6 as a predictive biomarker in the early diagnosis of postoperative systemic inflammatory response syndrome after a major thoracic operation.

METHODS

A total of 94 patients were enrolled in this prospective, clinical, single-center study. The enrolled subjects underwent either lung resection or esophageal operation. Interleukin 6, procalcitonin, C-reactive protein, and leucocytes were measured sequentially before, during, and after the operation. These levels were compared between patients who developed postoperative systemic inflammatory response syndrome and those who did not.

RESULTS

The enrollees who completed the study included of 55 males (79.7%) and 14 females (20.3%) with a mean age of 60.9 years. Twenty patients (29.0%) developed systemic inflammatory response syndrome at a median time of 33.0 hours postoperatively. In cases of postoperative systemic inflammatory response syndrome, interleukin 6 was the most predictive biomarker, showing a striking increase on the day of operation and preceding the median onset of postoperative systemic inflammatory response syndrome, which occurred the next day (P ≤ .001). Peak procalcitonin and C-reactive protein occurrence were significantly delayed at 24 hours (P = .012) and 48 hours (P = .012). There was no mortality 30 days postoperatively.

CONCLUSION

Interleukin 6 is a reliable predictor of postoperative systemic inflammatory response syndrome, and it is able to detect postoperative system inflammatory response syndrome before the onset of related clinical symptoms. When identifying patients at high risk, it would be beneficial to include interleukin 6 in conventional postoperative monitoring, particularly after extended surgical resection.

Predictive values for procalcitonin in the diagnosis of neonatal sepsis

BACKGROUND

Early diagnosis of neonatal sepsis followed by appropriate treatment decreases mortality and morbidity in infants. The aim of this study is to assess the role of procalcitonin (PCT) as a marker in the early diagnosis of neonatal sepsis.

METHODS

We present a cross sectional study where 35 neonates with early onset sepsis (admitted to the Neonatal Intensive Care Units at El-Minia Children University Hospital from August 2012 to August 2013) were included in the study. Another 35 healthy neonates with no clinical or biological data of infection were included as a control group. Subjects were subjected to a thorough history taking and routine laboratory investigations. Serum PCT and C-reactive protein (CRP) levels were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Mean levels of PCT and CRP in neonates with sepsis were significantly higher than in the control group (p=0.0001). There was a moderate, but significant, positive correlation between PCT and C-reactive protein (p=0.001, r=0.55) and an insignificant correlation between procalcitonin and total leukocytic count among the neonates with sepsis (p=0.2, r=0.2). In addition, procalcitonin had high sensitivity, specificity, a high positive predictive value, and a high negative predictive value (80%, 85.7%, 84.8%, and 81.1% respectively). Procalcitonin showed higher sensitivity when compared to CRP.

CONCLUSION

Procalcitonin is a sensitive, independent, and useful biomarker in comparison to CRP in early diagnosis of neonatal sepsis.

Use of early biomarkers in neonatal brain damage and sepsis: state of the art and future perspectives

The identification of early noninvasive biochemical markers of disease is a crucial issue of the current scientific research, particularly during the first period of life, since it could provide useful and precocious diagnostic information when clinical and radiological signs are still silent. The ideal biomarker should be practical and sensitive in the precocious identification of at risk patients. An earlier diagnosis may lead to a larger therapeutic window and improve neonatal outcome. Brain damage and sepsis are common causes of severe morbidity with poor outcome and mortality during the perinatal period. A large number of potential biomarkers, including neuroproteins, calcium binding proteins, enzymes, oxidative stress markers, vasoactive agents, and inflammatory mediators, have been so far investigated. The aim of the present review was to provide a brief overview of some of the more commonly investigated biomarkers used in case of neonatal brain damage and sepsis.

Role of biomarkers in sepsis care

Sepsis is one of the leading causes of mortality and morbidity, even with the current availability of extended-spectrum antibiotics and advanced medical care. Biomarkers offer a tool in facilitating early diagnosis, in identifying patient populations at high risk of complications, and in monitoring progression of the disease, which are critical assessments for appropriate therapy and improvement in patient outcomes. Several biomarkers are already available for clinical use in sepsis; however, their effectiveness in many instances is limited by the lack of specificity and sensitivity to characterize the presence of an infection and the complexity of the inflammatory and immune processes and to stratify patients into homogenous groups for specific treatments. Current advances in molecular techniques have provided new tools facilitating the discovery of novel biomarkers, which can vary from metabolites and chemical products present in body fluids to genes and proteins in circulating blood cells. The purpose of this review was to examine the current status of sepsis biomarkers, with special emphasis on emerging markers, which are undergoing validation and may transition into clinical practice for their informative value in diagnosis, prognosis, or response to therapy. We will also discuss the new concept of combination biomarkers and biomarker risk models, their existing challenges, and their potential use in the daily management of patients with sepsis.

Diagnostic accuracy of lipopolysaccharide-binding protein for predicting bacteremia/clinical sepsis in children with febrile neutropenia: comparison with interleukin-6, procalcitonin, and C-reactive protein

PURPOSE

In febrile neutropenia (FN), no reliable marker has been identified to discriminate between severe infection and other causes of fever early in the clinical course. Since lipopolysaccharide-binding protein (LBP) has proven to be an accurate biomarker of bacteremia/clinical sepsis in critically ill non-immunocompromised infants and children, we performed a prospective study to determine the diagnostic accuracy of LBP in children with FN.

METHODS

Concentrations of LBP, procalcitonin (PCT), interleukin-6 (IL-6), and C-reactive protein (CRP) were prospectively measured on two consecutive days in 90 FN episodes experienced by 47 children. Receiver operating characteristic curve analysis was performed for each biomarker to predict bacteremia/clinical sepsis and severe sepsis.

RESULTS

Eighteen of the 90 episodes were classified as bacteremia/clinical sepsis. On both days 1 and 2, all biomarkers had a low to intermediate diagnostic accuracy for sepsis, and no significant differences were found between them (area under the curve (AUC) for LBP, 0.648 and 0.714; for PCT, 0.665 and 0.744; for IL-6, 0.775 and 0.775; and for CRP, 0.695 and 0.828). Comparison of their AUCs to the AUC of maximum body temperature on admission (AUC = 0.668) also failed to show any significant differences. In severe sepsis, however, the best diagnostic accuracies were found for IL-6 and PCT (AUC 0.892 and 0.752, respectively), and these were significantly higher than those for LBP (AUC 0.566) on admission.

CONCLUSIONS

On admission and 24 h later, the LBP concentration is less accurate for predicting bacteremia/clinical sepsis compared to IL-6, PCT, and CRP.

Lipopolysaccharide-binding protein: a potential marker of febrile urinary tract infection in childhood

BACKGROUND

Urinary tract infections (UTIs) are encountered frequently in children, and their early diagnosis and treatment are important. This study evaluates the diagnostic value of serum concentrations of lipopolysaccharide-binding protein (LBP), an acute-phase protein, in children with febrile UTI and compares it to those of the total white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6).

METHODS

The study population comprised 77 consecutive patients with a first-episode febrile UTI (33 boys) with a median age of 11 months [interquartile range (IQR), 5.5-33 months], 21 healthy controls (11 boys) with a median age of 10 months (IQR, 5-20.5 months) and 58 febrile controls with a fever due to other causes (28 boys) with a median age of 12.5 months (IQR, 7-30 months). LBP, IL-6, PCT, and CRP were measured for both patients and control groups.

RESULTS

The serum levels of LBP (p  <  0.001), CRP (p  <  0.001), PCT (p  =  0.001), IL-6 (p  =  0.002), ESR (p  =  0.020), and WBC (p  <  0.001) were higher in patients with febrile UTI than in the healthy and febrile control groups. The LPB cut-off value for best sensitivity and specificity in patients with febrile UTI was >43.23 mg/l. Furthermore, the area under the receiver operating characteristic curve was significantly greater for LBP than for CRP (p  =  0.014), PCT (p  <  0.001), ESR (p  <  0.001), WBC (p  =  0.002) and IL-6 (p  =  0.006).

CONCLUSIONS

The results of this study suggest that the serum LBP concentration constitutes a reliable biologic marker for the diagnosis of a febrile UTI in children.

Procalcitonin in pediatrics

Over the past two decades, the body of literature on the clinical usefulness of procalcitonin (PCT) in adults has grown rapidly. Although this approach has led to increased insight, it has also prompted debate regarding its potential use in diagnosis and management of severe infection. Clinicians, however, are less familiar with the use of PCT in pediatric populations. In this review, we examine PCT as a marker of severe clinical pediatric conditions including its role in systemic inflammation, infection, and sepsis.

Procalcitonin as a predictive biomarker for total body irradiation-induced bacterial load and lethality in mice

Sepsis is the leading cause of mortality in intensive care units. Early detection and intervention are critical to prevent death. The acute radiation syndrome is characterized by damage of the gastrointestinal and hematopoietic systems. Translocation of intestinal microflora combined with immune system compromise may lead to septicemia and death. This work examined the utility of procalcitonin, a clinical sepsis biomarker, in a mouse model of radiation toxicity. C57/BL6 mice were exposed to total body irradiation (TBI). Intestinal mucosal permeability was measured in vivo, and liver bacterial load and plasma levels of procalcitonin (PCT), lipopolysaccharide (LPS), and LPS-binding protein were measured at baseline and at 3.5, 7, and 10 days after TBI. The value of early PCT in predicting subsequent lethality was determined by receiver operating characteristic analysis. Four days after TBI, a dose-dependent increase in permeability of the intestinal mucosa was observed, whereas bacterial translocation was present from day 7 onward. There was a high positive correlation between bacterial translocation and all sepsis biomarkers, with PCT exhibiting the strongest correlation. Moreover, plasma PCT levels were elevated already from day 3.5 onward, whereas LPS was elevated from day 7 and LPS-binding protein only 10 days after TBI. Receiver operating characteristic analysis revealed that PCT levels measured 3.5 days after TBI predicted lethality at 10 days. These data demonstrate the value of PCT as an early biomarker in radiation-induced bacteremia for mouse studies and suggest that clinical results from other septic conditions may apply to postradiation septicemia in humans.

Emerging biomarkers for the diagnosis of severe neonatal infections applicable to low resource settings

More than 500 000 children die each year in low resource settings due to serious neonatal infections. Better diagnostics that can be utilized in these settings to identify infected infants have the potential to significantly reduce neonatal deaths and the associated morbidity. A systematic review was performed and identified more than 250 potential new biomarkers for the diagnosis of serious neonatal infections. Eight of these biomarkers were both high-performance and high-abundance (antithrombin, inter-α inhibitor proteins, interferon-γ inducible protein-10, interleukin-1 receptor antagonist, LPS binding protein, mannose binding lectin, serum amyloid A, resistin, visfatin), and are promising for the diagnosis of serious neonatal infections in low resource settings. Future clinical trials comparing these biomarkers with more traditional biomarkers seem warranted.

Lipopolysaccharide-binding protein for monitoring of postoperative sepsis: complemental to C-reactive protein or redundant?

INTRODUCTION

To prospectively evaluate the performance of Lipopolysaccharide-Binding Protein (LBP) in prediction of hospital mortality and its correlation to C-reactive Protein (CRP), we studied sixty consecutive, postoperative patients with sepsis admitted to the university hospital intensive care unit.

MEASUREMENTS AND METHODS

Plasma LBP and CRP were serially measured from day(d)1 (onset of sepsis) to d14 in parallel with clinical data until d28. Predictive value and correlation of LBP and CRP were analyzed by Receiver Operating Characteristic (ROC) curve analysis and Pearson's test, respectively.

MAIN RESULTS

LBP and CRP showed the highest levels on d2 or d3 after the onset of sepsis with no significant difference between survivors and nonsurvivors. Only at d7, nonsurvivors had significantly (p = .03) higher levels of CRP than survivors. Accordingly, in ROC analysis, concentration of CRP and LBP on d7 poorly discriminated survivors from nonsurvivors (area under curve = .62 and .55, respectively) without significant difference between LBP- and CRP-ROC curves for paired comparison. LBP and CRP plasma levels allocated to quartiles correlated well with each other (r(2) = .95; p = .02). Likewise, changes in plasma concentrations of LBP and CRP from one observation to the next showed a marked concordance as both parameters concomitantly increased or decreased in 76% of all cases.

CONCLUSIONS

During the first 14 days of postoperative sepsis, LBP plasma concentrations showed a time course that was very similar to CRP with a high concordance in the pattern of day-to-day changes. Furthermore, like CRP, LBP does not provide a reliable clue for outcome in this setting.

Lipopolysaccharide binding protein, interleukin-6 and C-reactive protein in acute gastrointestinal infections: value as biomarkers to reduce unnecessary antibiotic therapy

AIM

Several new biomarkers, such as lipopolysaccharide binding protein (LBP) and interleukin-6 (IL-6), have the potential to determine the severity and outcome of infectious diseases. LBP and IL-6 serum levels have not been reported in patients with gastrointestinal infections. The aim of this study was to compare established markers of infection with new markers, such as LBP and IL-6, in patients with acute gastrointestinal infections

METHOD

LBP, C-reactive protein (CRP), white blood cell count (WBC) and IL-6 serum levels were determined in patients with acute viral or bacterial (positive stool cultures) gastroenteritis. The final diagnosis and empiric antibiotic use were recorded. In total, medical data on 88 patients with acute gastroenteritis (22 bacterial, 66 viral or nonspecific) were analyzed.

RESULTS

LBP and CRP levels were significantly increased in patients with acute bacterial gastroenteritis [28.5 ± 16.5 vs. 15.2 ± 11.5 μg/mL (p < 0.05) and 10.4 ± 9.6 vs. 3.8 ± 5.5 mg/dL (p < 0.001), respectively]. LBP at a cut-off value of 14.6 μg/mL and CRP at a cut-off value of 1.7 mg/dL distinguished between bacterial and non-bacterial gastrointestinal infection (receiver operator characteristic analysis). Empiric antibiotic therapy was initiated in 82% of patients with bacterial gastroenteritis and in 27% of patients with viral gastroenteritis.

CONCLUSION

The use of the cut-off values for LBP and CRP determined here would have avoided unnecessary antibiotic therapy in 14 and 11%, of patients respectively. CRP and LBP appear to be superior to IL-6 and WBC as diagnostic markers of bacterial gastrointestinal infection. Cut-off values may be a useful tool to support clinical decision-making on whether or not to initiate empiric antibiotic therapy.

Maternal plasma lipopolysaccharide binding protein (LBP) concentrations in pregnancy complicated by preterm premature rupture of membranes

OBJECTIVES

To compare maternal plasma LBP concentrations in pregnancies complicated by preterm premature rupture of membranes (pPROM), and PROM at term, with their levels in uncomplicated pregnancy, and to determine whether LBP concentrations are of value in the diagnosis of subclinical intra-amniotic infection (IAI) in the prediction of the length of the pPROM-to-delivery interval, and in the prediction of neonatal congenital infection.

STUDY DESIGN

Thirty-one patients with pPROM, 35 with PROM at term, 33 healthy women at preterm gestation and 35 healthy women at term were included. In the pPROM group, analysis of maternal plasma LBP concentrations with reference to leukocytosis, C-reactive protein, vaginal fluid culture, neonatal infection and pPROM-to-delivery interval was carried out.

RESULTS

LBP concentrations in the four studied groups were comparable. Although in 58.1% of pPROM cases at least one laboratory parameter of infection was observed, the only difference concerned the subgroup with CRP above 10mg/L, in which LBP concentrations were higher. Comparison of LBP concentrations in patients delivered within 24 and 72h of pPROM and after these times showed no differences, or between patients who gave birth to newborns with and without congenital infection. The predictive values of these measurements were poor.

CONCLUSION

The predictive value of maternal LBP determinations in the diagnostics of pPROM cases suspected of IAI is unsatisfactory. LBP measurements performed shortly after pPROM, are not of value either in the prediction of newborn's infection, or in the prognosis of latency period duration.

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.

High-mobility group box-1 protein, lipopolysaccharide-binding protein, interleukin-6 and C-reactive protein in children with community acquired infections and bacteraemia: a prospective study

Introduction

Even though sepsis is one of the common causes of children morbidity and mortality, specific inflammatory markers for identifying sepsis are less studied in children. The main aim of this study was to compare the levels of high-mobility group box-1 protein (HMGB1), Lipopolysaccharide-binding protein (LBP), Interleukin-6 (IL-6) and C-reactive protein (CRP) between infected children without systemic inflammatory response syndrome (SIRS) and children with severe and less severe sepsis. The second aim was to examine HMGB1, LBP, IL6 and CRP as markers for of bacteraemia.

Methods

Totally, 140 children with suspected or proven infections admitted to the Children's Clinical University Hospital of Latvia during 2008 and 2009 were included. Clinical and demographical information as well as infection focus were assessed in all patients. HMGB1, LBP, IL-6 and CRP blood samples were determined. Children with suspected or diagnosed infections were categorized into three groups of severity of infection: (i) infected without SIRS (n = 36), (ii) sepsis (n = 91) and, (iii) severe sepsis (n = 13). They were furthermore classified according bacteraemia into (i) bacteremia (n = 30) and (ii) no bacteraemia (n = 74).

Results

There was no statistically significant difference in HMGB1 levels between children with different levels of sepsis or with and without bacteraemia. The levels of LBP, IL-6 and CRP were statistically significantly higher among patients with sepsis compared to those infected but without SIRS (p < 0.001). Furthermore, LBP, IL-6 and CRP were significantly higher in children with severe sepsis compared to those ones with less severe sepsis (p < 0.001). Median values of LBP, IL6 and CRP were significantly higher in children with bacteraemia compared to those without bacteraemia. The area under the receiver operating curve (ROC) for detecting bacteraemia was 0.87 for both IL6 and CRP and 0.82 for LBP, respectively.

Conclusion

Elevated levels of LBP, IL-6 and CRP were associated with a more severe level of infection in children. Whereas LBP, IL-6 and CRP seem to be good markers to detect patients with bacteraemia, HMGB1 seem to be of minor importance. LBP, IL-6 and CRP levels may serve as good biomarkers for identifying children with severe sepsis and bacteraemia and, thus, may be routinely used in clinical practice.

Neutrophil and monocyte CD64 indexes, lipopolysaccharide-binding protein, procalcitonin and C-reactive protein in sepsis of critically ill neonates and children

OBJECTIVE

To compare the diagnostic accuracy of neutrophil and monocyte CD64 indexes (CD64in and CD64im) for sepsis in critically ill neonates and children with that of lipopolysaccharide-binding protein (LBP), procalcitonin (PCT) and C-reactive protein (CRP).

DESIGN AND SETTING

Prospective, observational study in a level III multidisciplinary neonatal and pediatric intensive care unit (ICU).

PATIENTS

Forty-six neonates and 36 children with systemic inflammatory response syndrome (SIRS) and suspected infection, classified into two groups: those with bacterial sepsis (microbiologically proven or clinical sepsis) and those without bacterial sepsis (infection not supported by subsequent clinical course, laboratory data and microbiological tests).

INTERVENTIONS AND MEASUREMENTS

Flow cytometric CD64in and CD64im, serum LBP, PCT and CRP measurement on 2 consecutive days from admission to the ICU.

RESULTS

There were 17 cases of bacterial sepsis in neonates and 24 cases of bacterial sepsis in children. All neonates and the majority of children were mechanically ventilated, and more than two-thirds of neonates with sepsis and one-third of children with sepsis needed inotropic/vasopressor drugs. The highest diagnostic accuracy for sepsis on the 1st day of suspected sepsis was achieved by LBP in neonates (0.86) and by CD64in in children (0.88) and 24 h later by CD64in in neonates (0.96) and children (0.98).

CONCLUSIONS

Neutrophil CD64 index (CD64in) is the best individual marker for bacterial sepsis in children, while in neonates the highest diagnostic accuracy at the time of suspected sepsis was achieved by LBP and 24 h later by CD64in.

Serum interleukin-6 (IL-6) and IL-10 concentrations in normal and septic neonatal foals

Previously it was reported that compared to surviving septic foals, non-surviving foals had a 35-fold increase in interleukin-10 (IL-10) and 15-fold increase in IL-6 gene expression in their peripheral blood mononuclear cells (PBMC). As gene expression profiles can be time-consuming, we sought to determine if serum IL-6 and IL-10 in foals would aid in the diagnosis and prognosis of septicemia. A prospective study of septic neonatal foals admitted to the Cornell University Equine Hospital during 2007 and 2008 was performed. Septicemia was confirmed in 15 foals using blood culture results and sepsis scores. Blood samples for measurement of serum IL-6 and IL-10 concentrations were collected at the time of admission (T0) and again 24 (T24) and 48 (T48) hours later. Blood samples from age-matched control foals (n=15) born at the Cornell Equine Park were obtained from foals 12-72h after birth (T0) and again 24 (T24) and 48 (T48) hours later. IL-6 and IL-10 concentrations were determined in the serum from dams of septic foals and serum and colostrum from dams of control foals. Serum IL-6 was also measured in healthy foals prior to ingestion of colostrum. Interleukin-6 was detected using an ELISA and IL-10 was detected using a bead-based fluorescent immunoassay. Group differences were detected using a Wilcoxon rank sum test with a Bonferroni correction applied to the p value. There were no significant differences in serum IL-10 concentration between the two groups of foals. Relative to control foals, septic foals had significantly lower serum IL-6 concentrations at all 3 time points. Relative to septic foals, control foals had significantly higher serum IL-6:IL-10 ratios. Serum IL-6 was undetectable in foals prior to ingestion of colostrum. However, colostral IL-6 concentration measured in the control mares was high (> or =215ng/mL) in all samples suggesting passive transfer of maternal IL-6 to the equine neonate. Colostral IL-10 was undetectable in 11/12 samples. Failure of passive transfer may directly influence the serum IL-6 concentration in septic foals. Neither serum IL-6 nor IL-10 alone, were useful diagnostic indices of sepsis in equine neonates. Although the number of animals involved in this study was too small for the identification of a concrete value, the serum IL-6:IL-10 ratio is likely to provide a valuable prognosticator for neonatal septicemia.

Lipopolysaccharide binding protein in the early diagnosis of intraamniotic infection of pregnant women with premature rupture of the membranes

AIMS

To investigate whether lipopolysaccharide binding protein (LBP) level is an early marker of intraamniotic infection in pregnant women with premature rupture of the membranes (PROM) and compare it to C-reactive protein (CRP).

METHODS

Seventy-two pregnant women with PROM were included in the study if remained undelivered for more than 24 h. CRP and LBP concentrations were determined in 12-h-intervals and the last value before delivery was correlated with obstetrical data and placenta histology.

RESULTS

LBP concentrations ranged from 1.6 to 48.7 microg/mL (median of 16 microg/mL) and CRP concentrations from 0.02 to 6.8 mg/dL (0.64 mg/dL). CRP was significantly elevated when full blown chorioamnionitis was proven by histology (P<0.01) and when the neonates had to be admitted to the intensive care unit because of suspected infection (P<0.05 mg/dL). There were significantly higher LBP levels when fetal tachycardia occurred (20.3 vs. 14.5 microg/mL, P<0.05) and when intraamniotic infection was diagnosed by histology (22.8 vs. 14.1 microg/mL, P<0.005), but the differences were too little to provide prognostic cut-off values.

CONCLUSION

Increase of LBP and CRP levels after PROM seem to reflect intramniotic infection, but no cut-off values could be defined for the prediction of intraamniotic infection.

Lipopolysaccharide binding protein in a surgical intensive care unit: a marker of sepsis?

OBJECTIVES

We investigated the time course of lipopolysaccharide binding protein (LBP) plasma concentrations in patients in the surgical intensive care unit (ICU), their value in discriminating sepsis from systemic inflammatory response syndrome, and their association with severity of sepsis and outcome in these patients compared with interleukin (IL)-6, C-reactive protein, and procalcitonin.

DESIGN

Prospective, observational, cohort study.

SETTING

Academic ICU.

PATIENTS

All 327 consecutively admitted patients.

MEASUREMENTS AND MAIN RESULTS

Serum LBP concentrations were higher in patients who had severe sepsis/septic shock on ICU admission than in patients who never had sepsis (20.5 [8.1-38.8] vs. 14.2 [7.7-22.2] microg/mL, p < .05) but were similar in patients with sepsis without organ failure and those who never had sepsis. After 3 days, LBP levels were similar in all groups. In a receiver operating characteristic curve analysis, LBP concentrations moderately discriminated sepsis from systemic inflammatory response syndrome (area under curve [AUC] = .66) and severe sepsis from sepsis without organ failure (AUC = .71). IL-6 had the highest AUC in discriminating sepsis from other conditions (AUC = .76) and procalcitonin had the highest AUC for discrimination of severe sepsis from sepsis (AUC = .86). LBP concentrations on admission and during the first week were similar in patients with gram-positive and those with gram-negative infections (15.9 [11-26.7] and 37.2 [25.1-62.4] vs. 16.3 [5.3-31.6] and 31.6 [13.4], microg/mL, p > .2). LBP concentrations on admission were similar in nonsurvivors and survivors and did not discriminate ICU mortality. However, the maximum LBP concentration during the first 3 days in the ICU discriminated moderately between survivors and nonsurvivors.

CONCLUSIONS

In the surgical ICU, LBP moderately discriminated patients without infection from patients with severe sepsis but not from patients with sepsis without organ dysfunction. LBP concentrations did not distinguish between gram-positive and gram-negative infections. The correlation of LBP concentrations with disease severity and outcome is weak compared with other markers and its use as a biomarker is not warranted in this patient population.

Procalcitonin and C-reactive protein as markers of bacterial infection in critically ill children at onset of systemic inflammatory response syndrome

OBJECTIVE

To compare the accuracy of procalcitonin and C-reactive protein as diagnostic markers of bacterial infection in critically ill children at the onset of systemic inflammatory response syndrome (SIRS).

DESIGN

Prospective cohort study.

SETTING

Tertiary care, university-affiliated pediatric intensive care unit (PICU).

PATIENTS

Consecutive patients with SIRS.

INTERVENTIONS

From June to December 2002, all PICU patients were screened daily to include cases of SIRS. At inclusion (onset of SIRS), procalcitonin and C-reactive protein levels as well as an array of cultures were obtained. Diagnosis of bacterial infection was made a posteriori by an adjudicating process (consensus of experts unaware of the results of procalcitonin and C-reactive protein). Baseline and daily data on severity of illness, organ dysfunction, and outcome were collected.

MEASUREMENTS AND MAIN RESULTS

Sixty-four patients were included in the study and were a posteriori divided into the following groups: bacterial SIRS (n = 25) and nonbacterial SIRS (n = 39). Procalcitonin levels were significantly higher in patients with bacterial infection compared with patients without bacterial infection (p = .01). The area under the receiver operating characteristic curve for procalcitonin was greater than that for C-reactive protein (0.71 vs. 0.65, respectively). A positive procalcitonin level (>or=2.5 ng/mL), when added to bedside clinical judgment, increased the likelihood of bacterial infection from 39% to 92%, while a negative C-reactive protein level (<40 mg/L) decreased the probability of bacterial infection from 39% to 2%.

CONCLUSIONS

Procalcitonin is better than C-reactive protein for differentiating bacterial from nonbacterial SIRS in critically ill children, although the accuracy of both tests is moderate. Diagnostic accuracy could be enhanced by combining these tests with bedside clinical judgment.

Lipopolysaccharide binding protein and sCD14 are not produced as acute phase proteins in cardiac surgery

Objectives. The changes in the serum levels of lipopolysaccharide binding protein (LBP) and sCD14 during cardiac surgery were followed in this study. Design. Thirty-four patients, 17 in each group, were randomly assigned to coronary artery bypass grafting surgery performed either with (“on-pump”) or without (“off-pump”) cardiopulmonary bypass. LBP and sCD14 were evaluated by ELISA. Results. The serum levels of LBP were gradually increased from the 1st postoperative day and reached their maximum on the 3rd postoperative day in both “on-pump” and “off-pump” patients (30.33±9.96μg/mL; 37.99±16.58μg/mL), respectively. There were no significant differences between “on-pump” and “off-pump” patients regarding LBP. The significantly increased levels of sCD14 from the 1st up to the 7th postoperative day in both “on-pump” and “off-pump” patients were found with no significant differences between these groups. No correlations between LBP and sCD14 and IL-6, CRP and long pentraxin PTX3 levels were found. Conclusions. The levels of LBP and sCD14 are elevated in cardiac surgical patients being similar in both groups. These molecules are not produced as acute phase proteins in these patients.

Nuclear factor-kappaB activation in peripheral blood mononuclear cells in children with sepsis

OBJECTIVE

To determine the activation of nuclear factor-[kappa]B in peripheral blood CD14+ monocyte/macrophages and CD3+, CD4+, and CD8+ T cells in children with sepsis.

DESIGN

Observational study.

SETTING

University hospital.

PATIENTS

Twenty-six children with sepsis (nine females and 17 males, aged between 10 days and 15 yrs; median, 4.3 yrs) on admission to our hospital between August 1999 and November 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The percentages of peripheral blood CD14+ monocyte/macrophages and CD3+, CD4+, and CD8+ T cells exhibiting nuclear factor-[kappa]B activity were determined by flow cytometry. In addition, relationships among the degree to which nuclear factor-[kappa]B was activated, serum levels of cytokines (interferon-[gamma], tumor necrosis factor-[alpha], interleukin-2, interleukin-4, interleukin-6, and interleukin-10), and clinical variables were analyzed. The percentage of cells exhibiting nuclear factor-[kappa]B activity was increased among CD14+, CD3+, CD4+, and CD8+ cells in the sepsis group and was significantly higher among CD14+, CD3+, and CD4+ cells of the patients with severe sepsis (n = 9) than those of patients with nonsevere sepsis (n = 17). The percentage of cells exhibiting nuclear factor-[kappa]B activity was significantly higher among CD14+ cells than CD3+ cells in the patients with severe sepsis. In addition, this percentage was significantly higher among CD14+ cells than CD3+, CD4+, and CD8+ cells in septic patients who had positive blood cultures (n = 16). Serum interleukin-6 levels were correlated with the percentages of CD14+, CD3+, CD4+, and CD8+ cells exhibiting nuclear factor-[kappa]B activity, and serum IL-10 levels were correlated with the percentages of CD14+, CD3+, and CD4+ cells exhibiting nuclear factor-[kappa]B activity.

CONCLUSIONS

Nuclear factor-[kappa]B in peripheral blood mononuclear cells was activated in children with sepsis and was related the severity of sepsis.

Bactericidal permeability increasing protein gene variants in children with sepsis

OBJECTIVE

To evaluate the role of genetic polymorphisms of the bactericidal permeability increasing protein (BPI) in pediatric patients with sepsis.

DESIGN

Prospective, single-center, case-control study at the pediatric intensive care unit (PICU) of a university hospital.

PATIENTS

345 consecutive pediatric patients admitted to the PICU with fever, systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, septic shock, or multiple organ distress syndrome (MODS).

INTERVENTIONS

DNA was isolated and two BPI gene polymorphisms BPI (G545 > C) Taq and BPI (A645[ > G) 216 were studied in patients and compared with healthy controls.

MEASUREMENTS AND RESULTS

Genetic analysis of the BPI Taq gene revealed significant differences between healthy controls and the subgroup of febrile patients (p = 0.0243), the subgroup of SIRS and sepsis (p = 0.0101), and the subgroup of severe sepsis, septic shock, and MODS (p = 0.0027), respectively. No statistically significant differences for the BPI 216 gene polymorphism were found between patient and healthy control groups. A statistically significant predisposition to Gram-negative sepsis in patients carrying the BPI Taq GG variant together with the BPI 216 AG or GG variant was revealed (p = 0.0081), and these haplotypes were also associated with death due to sepsis-related complications.

CONCLUSION

BPI Taq gene polymorphism is the accurate predictor of the severity of sepsis in children admitted to the PICU.

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.

Interleukin-6 and lipopolysaccharide-binding protein in acute appendicitis in children

The aim of the study was to evaluate the diagnostic accuracy of interleukin-6 (IL-6) and lipopolysaccharide-binding protein (LBP) in children with acute appendicitis (AA) and to compare this with the diagnostic accuracy of routinely used C-reactive protein (CRP) and white blood cell (WBC) count. Eighty-two consecutive children admitted to our Department because of suspected AA were enrolled in this prospective study and classified into two groups: group 1 (49 children who underwent surgery for AA) and group 2 (33 children with no surgery with diagnosis of non-specific abdominal pain or sonographic mesenteric lymphadenitis). There were no negative appendectomies during the time of the study. The patients were further classified into three subgroups: subgroup 1A (43 patients with advanced AA), subgroup 2A (11 patients with mesenteric lymphadenitis) and subgroup 2B (10 patients with non-specific abdominal pain). The perforation rate was 32.7 %. WBC count and serum CRP, IL-6 and LBP were measured on admission. Area under receiver operating characteristic (ROC) curve (AUC), sensitivity, specificity and predictive values were evaluated. Serum IL-6 and LBP were significantly higher in group 1 than in group 2. The highest AUC for AA was that for IL-6 (0.776), followed by WBC count (0.684), CRP (0.637) and LBP (0.635). In conclusion, only IL-6, determined on admission, showed medium diagnostic accuracy, while other laboratory markers showed low diagnostic accuracy for AA in children. The new laboratory markers therefore do not significantly improve the diagnosis of AA.

Lipopolysaccharide-binding protein, lipopolysaccharide, and soluble CD14 in sepsis of critically ill neonates and children

OBJECTIVE

To compare the diagnostic accuracy of lipopolysaccharide-binding protein (LBP) for sepsis in critically ill neonates and children with the two markers participating in the same inflammatory pathway, lipopolysaccharide and soluble CD14.

DESIGN AND SETTING

Prospective, observational study in a multidisciplinary neonatal and pediatric intensive care unit.

PATIENTS

47 critically ill neonates and 49 critically ill children with systemic inflammatory response syndrome (SIRS) and suspected sepsis, classified into two groups: those with and those without sepsis.

INTERVENTIONS

Serum LBP, lipopolysaccharide, soluble CD14, C-reactive protein, and procalcitonin were measured on 2 consecutive days. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and predictive values were evaluated.

RESULTS

AUC for LBP on the first day of suspected infection was 0.97 in neonates aged under 48 h, 0.93 in neonates over 48 h and 0.82 in children. AUCs for lipopolysaccharide and soluble CD14 were 0.77 and 0.74 in neonates under 48 h, 0.53 and 0.76 in neonates over 48 h, and 0.72 and 0.53 in children. AUCs for procalcitonin and C-reactive protein were 0.65 and 0.89 in neonates under 48 h, 0.65 and 0.91 in neonates over 48 h, and 0.76 and 0.69 in children.

CONCLUSIONS

In critically ill neonates and children LBP concentration on the first day of suspected sepsis is a better marker of sepsis than lipopolysaccharide, soluble CD14, procalcitonin, and in neonates younger than 48 h and children, also a better marker than C-reactive protein. Lipopolysaccharide and soluble CD14 are not suitable markers for the differentiation of infectious and noninfectious SIRS.

Diagnostic markers for neonatal sepsis: comparing C-reactive protein, interleukin-6 and immunoglobulin M

This clinical study was conducted to evaluate the diagnostic value of C-reactive protein (CRP), interlekin-6 (IL-6) and immunoglobulin M (IgM) in the early diagnosis of neonatal sepsis. The diagnostic values of each marker separately or in combinations were evaluated. The optimal cut-off values of each marker in the diagnosis of neonatal sepsis were defined. Between December 2004 and March 2005, a total of 78 neonates at different ages with different diagnoses in a neonatal intensive care unit in North Jordan were enrolled. Patients were classified into 'sepsis' group, 'probable sepsis' group and 'no sepsis' group. Blood samples were collected for CRP, IL-6 and IgM determination. A CRP value of 5 mg/l was the best among the three parameters with 95% sensitivity and 98% negative predictive value. Combination between parameters was helpful in enhancing the ability to diagnose sepsis. The best combination was CRP > or = 5 mg/l and/or IgM of > or =20 mg/dl. We conclude that CRP, IL-6 and IgM are helpful in the early diagnosis of Gram-negative neonatal sepsis. However, CRP continues to be the best single test. The use of both CRP and IgM in combination was the most helpful in predicting Gram-negative neonatal sepsis. We speculate a significant role of this combination in making decisions regarding antibiotics treatment and upgrading the level of medical care and observation in a setting where Gram-negative micro-organisms are causing the majority of neonatal infections.

Lipopolysaccharide binding protein is a potential marker for invasive bacterial infections in children

BACKGROUND

The aim of this study was to test the hypothesis that elevated lipopolysaccharide binding protein (LBP) serum concentration is a useful marker in the early diagnosis of invasive bacterial infection in children. We measured LBP in serum and cerebrospinal fluid (CSF) of children with proven invasive infection caused by Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis.

PATIENTS AND METHODS

Samples were collected from 39 children (aged 2 months to 17 years) with bacterial sepsis (n = 19) or meningitis (n = 20). Bacterial infection was diagnosed when a blood or CSF culture was positive and clinical signs of invasive infection were present. The control group consisted of serum (n = 60) and CSF (n = 19) samples from children with neurologic disease, juvenile idiopathic arthritis or viral infection. In 10 patients with bacterial infection, follow-up samples (24 and 48 hours) were available. LBP values were measured by an immunochemiluminescence analyzer (IMMULITE; DPC Biermann, Bad Nauheim, Germany) and compared with tumor necrosis factor-alpha and interleukin-8 concentrations.

RESULTS

The median LBP serum concentrations in patients with bacterial infection were markedly elevated compared with the control groups (45.0 [33.1-55.2] versus 8.3 [6.8-10.1] microg/mL [median and 5-95% confidence interval]; P < 0.0001). Follow-up serum values of LBP were persistently elevated despite adequate antibiotic treatment, whereas tumor necrosis factor-alpha and interleukin-8 concentrations decreased. In contrast, LBP concentrations in the CSF were below the detection limit of 0.5 microg/mL in 67% of patients with bacterial meningitis (median <0.5 microg/mL), whereas tumor necrosis factor-alpha and interleukin-8 levels were highly elevated.

CONCLUSION

LBP serum concentration is elevated in serum of children with invasive bacterial infection and could be a promising diagnostic marker.

Procalcitonin, lipopolysaccharide-binding protein, interleukin-6 and C-reactive protein in community-acquired infections and sepsis: a prospective study

INTRODUCTION

Clinicians are in need of better diagnostic markers in diagnosing infections and sepsis. We studied the ability of procalcitonin, lipopolysaccharide-binding protein, IL-6 and C-reactive protein to identify patients with infection and sepsis.

METHODS

Plasma and serum samples were obtained on admission from patients with suspected community-acquired infections and sepsis. Procalcitonin was measured with a time-resolved amplified cryptate emission technology assay. Lipopolysaccharide-binding protein and IL-6 were measured with a chemiluminescent immunometric assay.

RESULTS

Of 194 included patients, 106 had either infection without systemic inflammatory response syndrome or sepsis. Infected patients had significantly elevated levels of procalcitonin, lipopolysaccharide-binding protein, C-reactive protein and IL-6 compared with noninfected patients (P < 0.001). In a receiver-operating characteristic curve analysis, C-reactive protein and IL-6 performed best in distinguishing between noninfected and infected patients, with an area under the curve larger than 0.82 (P < 0.05). IL-6, lipopolysaccharide-binding protein and C-reactive protein performed best in distinguishing between systemic inflammatory response syndrome and sepsis, with an area under the curve larger than 0.84 (P < 0.01). Procalcitonin performed best in distinguishing between sepsis and severe sepsis, with an area under the curve of 0.74 (P < 0.01).

CONCLUSION

C-reactive protein, IL-6 and lipopolysaccharide-binding protein appear to be superior to procalcitonin as diagnostic markers for infection and sepsis in patients admitted to a Department of Internal Medicine. Procalcitonin appears to be superior as a severity marker.

Diagnostic markers for neonatal sepsis

PURPOSE OF REVIEW

To review the current evidence on the use of infection markers for diagnostic evaluation of sepsis in neonates.

RECENT FINDINGS

Recent research in immunology has led to the discovery of cell surface antigens, chemokines, cytokines and acute phase proteins that can potentially be used to 'rule in' or 'rule out' sepsis. The diagnostic utilities of key inflammatory mediators, including CD11b, CD64, interleukin-6 and interleukin-8, are promising and likely to become increasingly used as markers of infection for both diagnostic and prognostic purposes.

SUMMARY

Serial measurements and use of combinations of markers have been reported to improve sensitivity and negative predictive value of these tests. Current markers are not infallible, however, and do not permit neonatologists to withhold antibiotics in sick infants with suspected infection. Thus, many have emerged as useful indicators for early discontinuation of unnecessary antimicrobial therapy. Some infection markers are also useful for identifying infants with severe infection and adverse prognosis. Advances in flow cytometry have allowed simultaneous measurement of key markers using only minimal blood volume. Judicious selection of a panel of markers with complementary properties could greatly increase the ability of neonatologists to diagnose infection and discern valuable prognostic information.

Biomarkers of sepsis: clinically useful?

PURPOSE OF REVIEW

The purpose of this review is to indicate recent developments in biomarkers of sepsis and to evaluate their impact on clinical use. According to the 'surviving sepsis campaign,' diagnosis of sepsis and infection is urgent; early and specific treatment is most effective to reduce complications and to decrease mortality.

RECENT FINDINGS

A variety of biomarkers of sepsis is presently available. The diagnostic spectrum of the various markers, however, is different. Some primarily indicate severity of inflammation (e.g. interleukin-6), others respond to infection, but do not indicate the host response well (endotoxin, lipoprotein binding protein, triggering receptor on myeloid cells). There are new markers with limited clinical experience, for example triggering receptor on myeloid cells or mid-pro atrial natriuretic peptide (Seristra, Brahms AG, Hennigsdorf, Germany). Procalcitonin is a well-established biomarker of sepsis that fulfills several criteria of clinical needs: it responds both to infection and severity of inflammation and thus has an impact on therapy. Recent studies indicate that antibiotic treatment can also be guided by procalcitonin. Further indications, including diagnosis of invasive bacterial infections and diagnosis of sepsis in neonates and children have been reported recently.

SUMMARY

Recent data and cumulative analyses indicate that biomarkers of sepsis improve diagnosis of sepsis. However, only a few markers have impact on therapy and fulfill the clinical requirements. Procalcitonin is a well-established marker, indicating infection, sepsis, and progression to the more severe stages of the disease. Today, this biomarker should be in the diagnostic portfolio of an intensive care unit or emergency ward.

Lipopolysaccharide-binding protein in noninfected neonates and those with suspected early-onset bacterial infection

OBJECTIVES

To investigate postnatal lipopolysaccharide-binding protein (LBP) kinetics in term neonates and to test its diagnostic accuracy for early-onset bacterial infection (EOBI).

STUDY DESIGN

A total of 99 neonates with clinical and serological signs of EOBI comprised the study group; 198 neonates with risk factors, but without EOBI, served as controls. LBP, C-reactive protein (CRP) and interleukin-8 (IL-8) were determined.

RESULTS

LBP in the noninfected group increased until 24 h after birth (P < 0.05 vs 6 h). LBP and CRP correlated strongly in neonates with suspected EOBI (r = 0.63). Although LBP reached a higher sensitivity than CRP 6 and 12 h after clinical suspicion (45 (24-68) and 79% (54-94) vs 9 (0-24) and 39% (17-64); P < 0.05)), EOBI was most reliably detected by IL-8.

CONCLUSION

LBP kinetics were age-dependent. LBP was not sufficiently sensitive in the prediction of EOBI.

The role of lipopolysaccharide-binding protein in modulating the innate immune response

Lipopolysaccharide-binding protein (LBP) has a well-established role in Gram-negative infection. New data suggest a more expanded role for LBP as a general recognition molecule. Several bacterial surface components from Gram-positive pathogens are also recognized by this molecule. LBP may also serve as a clinical marker in severe infections and may carry therapeutic potential.