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

The correlation between dysfunctional intestinal flora and pathology feature of patients with pulmonary tuberculosis

Introduction

Recent studies have provided insights into the important contribution of gut microbiota in the development of Pulmonary Tuberculosis (PTB). As a chronic consumptive infectious disease, PTB involves many pathological characteristics. At present, research on intestinal flora and clinical pathological Index of PTB is still rare.

Methods

We performed a cross-sectional study in 63 healthy controls (HCs) and 69 patients with untreated active PTB to assess the differences in their microbiota in feces via 16S rRNA gene sequencing.

Results

Significant alteration of microbial taxonomic and functional capacity was observed in PTB as compared to the HCs. The results showed that the alpha diversity indexes of the PTB patients were lower than the HCs (P<0.05). Beta diversity showed differences between the two groups (P<0.05). At the genus level, the relative abundance of Bacteroides, Parabacteroides and Veillonella increased, while Faecalibacterium, Bifidobacterium, Agathobacter and CAG-352 decreased significantly in the PTB group, when compared with the HCs. The six combined genera, including Lactobacillus, Faecalibacterium, Roseburia, Dorea, Monnoglobus and [Eubacterium]_ventriosum_group might be a set of diagnostic biomarkers for PTB (AUC=0.90). Besides, the predicted bacterial functional pathway had a significant difference between the two groups (P<0.05), which was mainly related to the nutrient metabolism pathway. Significant alterations in the biochemical index were associated with changes in the relative abundance of specific bacteria, the short chain fatty acid (SCFA)-producing bacteria enriched in HCs had a positively correlated with most of the biochemical indexes.

Discussion

Our study indicated that the gut microbiota in PTB patients was significantly different from HCs as characterized by the composition and metabolic pathway, which related to the change of biochemical indexes in the PTB group. It was hypothesized that the abovementioned changes in the gut microbiota could exert an impact on the clinical characteristics of PTB through the regulation of the nutrient utilization pathway of the host by way of the gut-lung axis.

Plasma proteome profiling reveals differentially expressed lipopolysaccharide-binding protein among leptospirosis patients

BACKGROUND

Human leptospirosis, or commonly known as "rat urine disease" is a zoonotic disease that is caused by the bacteria called Leptospira sp. The incidence rate of leptospirosis has been under-reported due to its unspecific clinical symptoms and the limitations of current laboratory diagnostic methods. Leptospirosis can be effectively treated with antibiotics in the early stage, and it is a curable disease but the accuracy to diagnose the infection is rarely achieved.

METHODS

The present pilot study investigated plasma protein profiles of leptospirosis patients and compared them against two control groups which consisted of dengue patients and healthy individuals. The plasma protein digests were analyzed using shotgun approach by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Protein abundances were estimated from the exponentially modified protein abundance index (emPAI) values. Plasma proteins in leptospirosis patients with at least two-fold differential expression compared to dengue and healthy control groups (p < 0.05, ANOVA) were identified.

RESULTS

Lipopolysaccharide (LPS)-binding protein (LBP) was found to be the only protein that has significant different expression between leptospirosis and the two control groups. The expression levels of leucine-rich alpha-2-glycoprotein (LRG1) and alpha-1-antichymotrypsin (ACT) were different significantly between leptospirosis and healthy group but not to the dengue control group.

CONCLUSION

This is the first plasma proteome-based study on leptospirosis that reports the differential expression of LBP compared to both dengue and healthy controls, which has not been previously reported in the context of leptospirosis.

Postprandial endotoxemia may influence the development of type 2 diabetes mellitus: From the CORDIOPREV study

BACKGROUND & AIMS

Insulin resistance (IR) and impaired beta-cell function are key determinants of type 2 diabetes mellitus (T2DM). Intestinal absorption of bacterial components activates the toll-like receptors inducing inflammation, and this in turn IR. We evaluated the role of endotoxemia in promoting inflammation-induced insulin resistance (IR) in the development of T2DM, and its usefulness as predictive biomarker.

METHODS

We included in this study 462 patients from the CORDIOPREV study without T2DM at baseline. Of these, 107 patients developed T2DM according to the American Diabetes Association (ADA) diagnosis criteria after a median follow-up of 60 months (Incident-DIAB group), whereas 355 patients did not developed it during this period of time (Non-DIAB group).

RESULTS

We observed a postprandial increase in lipopolysaccharides (LPS) levels in the Incident-DIAB at baseline (P < 0.001), whereas LPS levels were not modified in the Non-DIAB. Disease-free survival curves based on the LPS postprandial fold change improved T2DM Risk Assessment as compared with the previously described FINDRISC score (hazard ratio of 2.076, 95% CI 1.149-3.750 vs. 1.384, 95% CI 0.740-2.589). Moreover, disease-free survival curves combining the LPS postprandial fold change and FINDRISC score together showed a hazard ratio of 3.835 (95% CI 1.323-11.114), linked to high values of both parameters.

CONCLUSION

Our results suggest that a high postprandial endotoxemia precedes the development of T2DM. Our results also showed the potential use of LPS plasma levels as a biomarker predictor of T2DM development. CLINICAL TRIALS.GOV.

IDENTIFIER

NCT00924937.

Effect of Dietary Lipids on Endotoxemia Influences Postprandial Inflammatory Response

Metabolic syndrome (MetS) results in postprandial metabolic alterations that predisposes one to a state of chronic low-grade inflammation and increased oxidative stress. We aimed to assess the effect of the consumption of the quantity and quality of dietary fat on fasting and postprandial plasma lipopolysaccharides (LPS). A subgroup of 75 subjects with metabolic syndrome was randomized to receive 1 of 4 diets: HSFA, rich in saturated fat; HMUFA, rich in monounsaturated fat; LFHCC n-3, low-fat, rich in complex carbohydrate diet supplemented with n-3 polyunsaturated fatty acids; LFHCC low-fat, rich in complex carbohydrate diet supplemented with placebo, for 12 weeks each. We administered a fat challenge reflecting the fatty acid composition of the diets at postintervention. We determined the plasma lipoproteins and glucose and gene expression in peripheral blood mononuclear cells (PBMC) and adipose tissue. LPS and LPS binding protein (LBP) plasma levels were determined by ELISA, at fasting and postprandial (4 h after a fat challenge) states. We observed a postprandial increase in LPS levels after the intake of the HSFA meal, whereas we did not find any postprandial changes after the intake of the other three diets. Moreover, we found a positive relationship between the LPS plasma levels and the gene expression of IkBa and MIF1 in PBMC. No statistically significant differences in the LBP plasma levels at fasting or postprandial states were observed. Our results suggest that the consumption of HSFA diet increases the intestinal absorption of LPS which, in turn, increases postprandial endotoxemia levels and the postprandial inflammatory response.

Combined use of biomarkers for distinguishing between bacterial and viral etiologies in pediatric lower respiratory tract infections

BACKGROUND

In clinical practice it is often troublesome to discriminate bacterial etiologies from viral etiologies in pediatric lower respiratory tract infections (LRTIs). The aim of this study was to develop an accurate analytic method to improve diagnostic determination for bacterial and viral etiologies in pediatric LRTIs.

METHODS

A total of 45 children with confirmed bacterial LRTIs and 51 children with viral LRTIs were finally included after assessment of the children visiting the emergency department with a suspected infection and identification of pathogens. C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), CD35, and CD64 were assessed and then the areas under receiver operating characteristic (ROC) curves (AUC) of PCT, IL-6, CD35, and CD64 in combination with CRP were compared to the AUC of CRP alone in all subjects.

RESULTS

The levels of CRP, PCT, IL-6, CD45, and CD64 observed in children with bacterial LRTIs were statistically higher than for viral infections. The AUC of CRP combined with CD53 (0.963, 95% confidence interval (CI) 0.921-1.002) or CD64 (0.952, 95% CI 0.907-0.998) or CD35/CD64 (0.971, 95% CI 0.932-1.004) increased compared with that of the single biomarker.

CONCLUSIONS

The combined analysis improved diagnostic accuracy in children with bacterial and viral LRTIs.

The discriminative capacity of soluble Toll-like receptor (sTLR)2 and sTLR4 in inflammatory diseases

Background

The extracellular domains of cytokine receptors are released during inflammation, but little is known about the shedding of Toll-like receptors (TLR) and whether they can be used as diagnostic biomarkers.

Methods

The release of sTLR2 and sTLR4 was studied in in-vitro stimulations, as well as in-vivo during experimental human endotoxemia (n = 11, 2 ng/kg LPS), and in plasma of 394 patients with infections (infectious mononucleosis, measles, respiratory tract infections, bacterial sepsis and candidemia) or non-infectious inflammation (Crohn’s disease, gout, rheumatoid arthritis, autoinflammatory syndromes and pancreatitis). Using C-statistics, the value of sTLR2 and sTLR4 levels for discrimination between infections and non-infectious inflammatory diseases, as well as between viral and bacterial infections was analyzed.

Results

In-vitro, peripheral blood mononuclear cells released sTLR2 and sTLR4 by exposure to microbial ligands. During experimental human endotoxemia, plasma concentrations peaked after 2 hours (sTLR4) and 4 hours (sTLR2). sTLR4 did not correlate with cytokines, but sTLR2 correlated positively with TNFα (r_s = 0.80, P < 0.05), IL-6 (r_s = 0.65, P < 0.05), and IL-1Ra (r_s = 0.57, P = 0.06), and negatively with IL-10 (r_s = -0.58, P = 0.06), respectively. sTLR4 had a similar area under the ROC curve [AUC] for differentiating infectious and non-infectious inflammation compared to CRP: 0.72 (95% CI 0.66-0.79) versus 0.74 (95% CI 0.69-0.80) [P = 0.80], while sTLR2 had a lower AUC: 0.60 (95% CI 0.54-0.66) [P = 0.0004]. CRP differentiated bacterial infections better from viral infections than sTLR2 and sTLR4: AUC 0.94 (95% CI 0.90-0.96) versus 0.58 (95% CI 0.51-0.64) and 0.75 (95% CI 0.70-0.80), respectively [P < 0.0001 for both].

Conclusions

sTLRs are released into the circulation, and suggest the possibility to use sTLRs as diagnostic tool in inflammatory conditions.

The impact of microglial activation on blood-brain barrier in brain diseases

The blood-brain barrier (BBB), constituted by an extensive network of endothelial cells (ECs) together with neurons and glial cells, including microglia, forms the neurovascular unit (NVU). The crosstalk between these cells guarantees a proper environment for brain function. In this context, changes in the endothelium-microglia interactions are associated with a variety of inflammation-related diseases in brain, where BBB permeability is compromised. Increasing evidences indicate that activated microglia modulate expression of tight junctions, which are essential for BBB integrity and function. On the other hand, the endothelium can regulate the state of microglial activation. Here, we review recent advances that provide insights into interactions between the microglia and the vascular system in brain diseases such as infectious/inflammatory diseases, epilepsy, ischemic stroke and neurodegenerative disorders.

Increased Anti-Flagellin and Anti-Lipopolysaccharide Immunoglobulins in Pediatric Intestinal Failure: Associations With Fever and Central Line-Associated Bloodstream Infections

BACKGROUND

Central line-associated bloodstream infections (CLABSIs) pose a significant challenge in the lives of patients with intestinal failure (IF). We hypothesized that plasma immunoglobulins against flagellin (FLiC) and lipopolysaccharide (LPS) would be able to differentiate CLABSIs from nonbacterial febrile episodes and that levels would increase with infection and decline following appropriate antibiotic treatment.

MATERIALS AND METHODS

Patients with IF, due to short bowel syndrome, between the ages of 3 months and 4 years of age, were recruited at Cincinnati Children's Hospital Medical Center. Anti-FLiC and anti-LPS plasma antibody levels were measured in 13 children with IF at baseline, during febrile events, and also following treatment with antibiotics. These were also measured in 11 healthy children without IF who were recruited as controls.

RESULTS

Plasma anti-FLiC IgA levels increased during febrile episodes in all patients with IF (baseline mean of 1.10 vs febrile episode mean of 1.32 optical density units, respectively; P = .046). Neither plasma anti-FLiC nor anti-LPS IgA or IgG levels distinguished CLABSI from nonbacterial febrile episodes compared with baseline levels. Compared with controls, patients with IF had significantly higher plasma levels of anti-FLiC and anti-LPS IgA at baseline.

CONCLUSION

Plasma anti-FLiC IgA antibody levels rise during febrile episodes but do not differentiate between nonbacterial febrile illnesses and CLABSIs in pediatric IF. However, the upregulation of these antibodies in IF suggests the baseline systemic presence of Gram-negative bacterial products.

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.

The importance of biomarkers in neonatology

Despite a 35% decline in the mortality rate for infants aged <5 years over the past two decades, every year nearly 40% of all deaths in this age group occur in the neonatal period, defined as the first 28 days of life. New knowledge on molecular and biochemical pathways in neonatal diseases will lead to the discovery of new candidate biomarkers potentially useful in clinical practice. In the era of personalized medicine, biomarkers may play a strategic role in accelerating the decline in neonatal mortality by assessing the risk of developing neonatal diseases, by implementing tailored therapeutic treatment, and by predicting the clinical outcome. However, there is an urgent need to reduce the gap in translating newly acquired knowledge from bench to bedside. Traditional and candidate biomarkers for neonatal sepsis and necrotizing enterocolitis will be discussed in this review, such as C-reactive protein (CRP), procalcitonin (PCT), serum amyloid A (SAA), soluble form of CD14 subtype presepsin (sCD14-ST), lipolysaccharide binding protein (LBP), angiopoietins (Ang)-1 and -2, soluble form of triggering receptor expressed on myeloid cells (sTREM-1), soluble form of urokinase-type plasminogen activator receptor (suPAR), platelet-activating factor (PAF) and calprotectin. New frontiers in managing critically ill newborns may be opened by metabolomics, a diagnostic tool based on the recognition of metabolites contained in biological fluids. Metabolomics represents the passage from a descriptive science to a predictive science, having the potential to translate benchtop research to real clinical benefits.

Combination of biomarkers for the discrimination between bacterial and viral lower respiratory tract infections

OBJECTIVES

To investigate whether additional determinations of plasma lipopolysaccharide binding protein (LBP), procalcitonin (PCT), interleukin-6 (IL-6), IL-18, or soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) to C-reactive protein (CRP) improve the discrimination between bacterial and viral lower respiratory tract infections (LRTI).

METHODS

Out of 342 patients visiting the emergency department because of a suspected infection and ≥2 clinical signs of sepsis, 56 patients with proven bacterial (n = 39) or viral (n = 17) LRTI were included. The area under the ROC curves (AUC) of the five possible combinations of CRP with one other biomarker were compared with the AUC of CRP alone. Next, the same analysis was performed in the group of patients with a CRP concentration with <95% specificity for bacterial LRTI.

RESULTS

While CRP, PCT, IL-6, sTREM-1, and LBP concentrations were significantly different between patients with bacterial or viral LRTI, the AUC of CRP (0.82, 95% CI 0.70-0.93) did not increase after combination analyses. After exclusion of patients with a CRP >150 mg/l, biomarker panel analyses did not improve diagnostic accuracy of CRP either.

CONCLUSIONS

Combining CRP with LBP, PCT, IL-6, IL-18, or sTREM-1 does not improve differentiation between patients with a bacterial or viral LRTI compared with CRP alone.

Lipopolysaccharide binding protein is down-regulated during acute liver failure

BACKGROUND AND AIMS

Lipopolysaccharide binding protein (LBP) is involved in the modulation of acute liver injury and failure caused by acetaminophen (APAP). Although the biological activity of LBP is concentration dependent, little is known about its levels in acute liver failure.

METHODS

Serum and hepatic LBP were measured in acute APAP-induced liver injury in mice. Serum LBP was measured in patients with acute liver failure from APAP and non-APAP causes.

RESULTS

Interestingly, contrary to other diseases, serum and hepatic LBP levels decreased significantly in mice within 24 h after being subjected to APAP-induced injury compared to the control (1.6 ± 0.1 vs. 3.5 ± 1.6 μg/ml, respectively; P < 0.05). Similar decreases were noted in another mouse model of acute liver injury due to carbon tetrachloride. Among patients with acute liver failure due to APAP (n = 5) and non-APAP (n = 5) causes, admission LBP levels were decreased compared to those of healthy controls (5.4 ± 1.4 vs. 3.2 ± 0.2 μg/ml, normal vs. acute liver failure; P = 0.07). However, the levels were not associated with the etiology of acute liver failure or 3-week outcome.

CONCLUSIONS

Serum and hepatic LBP levels are significantly reduced early after the induction of severe acute liver injury/failure due to acetaminophen and other liver injuries. This reduction in LBP production is specific to acute liver failure and may be important in developing future diagnostic and therapeutic approaches for patients with acute liver failure.

The developing immune system - from foetus to toddler

During foetal development, neonatal period and childhood, the immune system is constantly maturing. In the foetus, infection responsiveness is low and associates with spontaneous abortion. During the neonatal period, the infection response shifts towards a more pro-inflammatory response. The immune system of the newborn acquires adaptive features as a result of exposure to microbes.

CONCLUSION

The development of the human immune system is a continuous process where both accelerated and retarded development is deleterious.

sTREM-1 and LBP in central venous catheter-associated bloodstream infections in pediatric intestinal failure

OBJECTIVE

Central venous catheter-associated bloodstream infections (CVC-BSIs) are a major cause of morbidity and mortality in the pediatric intestinal failure (IF) population. We assessed plasma lipopolysaccharide-binding protein (LBP) and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) as biomarkers for CVC-BSI. We hypothesized that sTREM-1 and LBP rise with BSI and decline following treatment, and that baseline LBP is higher in the IF population than in controls.

PATIENTS AND METHODS

Patients younger than 4 years were recruited from the IF registry at Cincinnati Children's Hospital. LBP and sTREM-1 levels were measured on 22 patients with IF at baseline, 17 patients with IF with BSIs, and 11 healthy controls.

RESULTS

Mean sTREM-1 level (pg/mL) and LBP level (μg/mL) rose with CVC-BSI over baseline (115.0 ± 51.2 vs 85.9 ± 27.6, P = 0.011 and 79.8 ± 45.4 vs 20.5 ± 11.3, P < 0.001, respectively) and declined following antibiotic therapy (115.0 ± 51.2 vs 77.9 ± 29.8, P = 0.003 and 79.8 ± 45.4 vs 26.2 ± 10.8, P < 0.001, respectively). Receiver operating characteristic curves showed that neither sTREM-1 nor LBP is sufficient to predict bacteremia versus fever without bacteremia (area under these curves = 0.57 and 0.82, respectively). Baseline LBP was higher in hospitalized patients than in outpatients (27.5 ± 8.7 vs 13.5 ± 9.2, P = 0.002), patients with previous BSIs versus those without (23.5 ± 10.4 vs 10.1 ± 8.3, P = 0.016), and those listed for transplantation versus those not listed (29.6 ± 9.8 vs 16.2 ± 9.5, P = 0.033).

CONCLUSIONS

sTREM-1 and LBP rise with CVC-BSI in IF and decline after treatment; however, neither distinguishes infection from nonbacteremic febrile episodes. Baseline LBP may be a marker of disease severity in IF.

Pathogenesis and pathophysiology of pneumococcal meningitis

Pneumococcal meningitis continues to be associated with high rates of mortality and long-term neurological sequelae. The most common route of infection starts by nasopharyngeal colonization by Streptococcus pneumoniae, which must avoid mucosal entrapment and evade the host immune system after local activation. During invasive disease, pneumococcal epithelial adhesion is followed by bloodstream invasion and activation of the complement and coagulation systems. The release of inflammatory mediators facilitates pneumococcal crossing of the blood-brain barrier into the brain, where the bacteria multiply freely and trigger activation of circulating antigen-presenting cells and resident microglial cells. The resulting massive inflammation leads to further neutrophil recruitment and inflammation, resulting in the well-known features of bacterial meningitis, including cerebrospinal fluid pleocytosis, cochlear damage, cerebral edema, hydrocephalus, and cerebrovascular complications. Experimental animal models continue to further our understanding of the pathophysiology of pneumococcal meningitis and provide the platform for the development of new adjuvant treatments and antimicrobial therapy. This review discusses the most recent views on the pathophysiology of pneumococcal meningitis, as well as potential targets for (adjunctive) therapy.

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.

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.

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.