Combination biomarkers to diagnose sepsis in the critically ill patient

Comprehensive analysis of multiple cytokines and blood parameters for the diagnosis of bacterial infections in rheumatoid arthritis

Patients with rheumatoid arthritis (RA) are more susceptible to infections, which elevate the levels of relative cytokines. However, the ability of the cytokines levels to predicate bacterial infections in RA patients remains unclear. Here, we assessed the ability of the combination of serum cytokine levels and blood parameters to diagnose bacterial infections in RA patients. We measured the levels of a panel of serum cytokine and blood parameters in 168 RA patients and 81 healthy individuals. RA patients were divided into the bacterial infection (INFE) group (n = 76) and RA flare without INFE group (n = 92). Bacterial infection was confirmed by microbial culture, imaging, antibiotic response, and typical clinical symptoms. The discriminative ability of the combination of the cytokine levels and inflammatory parameters was assessed using the receiver-operating characteristic (ROC) curves analysis and a novel bioscore system. The levels of interleukin (IL)-6 (p = 0.006), IL-10 (p = 0.019), interferon (IFN)-γ (p = 0.033), CRP (p < 0.001), and ESR (p < 0.001) were higher in patients of the INFE group than in patients with RA flare, and the absolute numbers of CD19⁺ B cells (p < 0.001) and CD4⁺ T cells (p = 0.009) were lower. For discriminating bacterial infection, the combination of IL-6, IL-10, IFN-γ, ESR, CRP, CD19⁺ B cells, and CD4⁺ T cells, provided an area under the curve (AUC) of 0.827 [(95% confidence interval (CI): 0.760-0.881)], which was profoundly larger than that of IL-6, IL-10, IFN-γ, ESR, CRP, CD19⁺ B cells, or CD4⁺ T cells alone. In addition, we also developed a bioscore system based on the combination of these seven biomarkers. Seventeen (100%) patients with a bioscore of 0 were non-infected, while seven (100%) patients with a score of 7 had bacterial infections. The bioscore based on the combination of ESR, CRP, IL-6, IL-10, IFN-γ, CD19⁺ B cells and CD4⁺ T cells may be a promising and robust tool to diagnose bacterial infections in RA patients.

Identification of progranulin as a novel diagnostic biomarker for early-onset sepsis in neonates

Neonatal early-onset sepsis (EOS) is associated with high morbidity and mortality. Accurate early diagnosis is crucial for prompt treatment and a better clinical outcome. We aimed to identify new biomarkers for the diagnosis of EOS. A total of 152 neonates with a risk of EOS were divided into an EOS group and a non-EOS group according to the conventional diagnostic criteria. Blood samples were collected within 0-24, 24-48, and 48-72 h after birth. Serum levels of progranulin (PGRN), interleukin (IL)-33, IL-17a, IL-23, IL-6, tumor necrosis factors α (TNF-α), interferon γ (IFN-γ), granulocyte-macrophage colony-stimulating factor (GM-CSF), procalcitonin (PCT), and C-reactive protein (CRP) were determined. PGRN levels were significantly elevated in the EOS neonates compared with the levels in the non-EOS neonates (1.53 vs. 0.77 ng/ml (median), P < 0.001), with an area under the receiver operating characteristic (ROC) curve (AUC) of 0.76 (P < 0.001). Compared with PGRN, IL-33, IL-17a, IL-23, IL-6, PCT, and CRP showed significant (AUC > 0.70) but slightly less predictive power for EOS within the same time range. Stepwise multivariate regression analysis identified PGRN, IL-33, and PCT as independent predictors of EOS. In addition, the combined measurements of PGRN, IL-33, and PCT showed significantly higher predictive power for EOS than any of the three markers alone. PGRN showed greater efficacy for predicting EOS than the traditional markers PCT and CRP as well as other potential markers tested in this study. PGRN may serve as an effective biomarker for the early diagnosis of EOS.

The plasma peptides of sepsis

Background

A practical strategy to discover sepsis specific proteins may be to compare the plasma peptides and proteins from patients in the intensive care unit with and without sepsis. The aim was to discover proteins and/or peptides that show greater observation frequency and/or precursor intensity in sepsis. The endogenous tryptic peptides of ICU-Sepsis were compared to ICU Control, ovarian cancer, breast cancer, female normal, sepsis, heart attack, Alzheimer’s and multiple sclerosis along with their institution-matched controls, female normals and normal samples collected directly onto ice.

Methods

Endogenous tryptic peptides were extracted from individual sepsis and control EDTA plasma samples in a step gradient of acetonitrile for random and independent sampling by LC–ESI–MS/MS with a set of robust and sensitive linear quadrupole ion traps. The MS/MS spectra were fit to fully tryptic peptides within proteins using the X!TANDEM algorithm. The protein observation frequency was counted using the SEQUEST algorithm after selecting the single best charge state and peptide sequence for each MS/MS spectra. The protein observation frequency of ICU-sepsis versus ICU Control was subsequently tested by Chi square analysis. The average protein or peptide log₁₀ precursor intensity was compared across disease and control treatments by ANOVA in the R statistical system.

Results

Peptides and/or phosphopeptides of common plasma proteins such as ITIH3, SAA2, SAA1, and FN1 showed increased observation frequency by Chi square (χ² > 9, p < 0.003) and/or precursor intensity in sepsis. Cellular gene symbols with large Chi square values from tryptic peptides included POTEB, CTNNA1, U2SURP, KIF24, NLGN2, KSR1, GTF2H1, KIT, RPS6KL1, VAV2, HSPA7, SMC2, TCEB3B, ZNF300, SUPV3L1, ADAMTS20, LAMB4, MCCC1, SUPT6H, SCN9A, SBNO1, EPHA1, ABLIM2, cB5E3.2, EPHA10, GRIN2B, HIVEP2, CCL16, TKT, LRP2 and TMF1 amongst others showed increased observation frequency. Similarly, increased frequency of tryptic phosphopeptides were observed from POM121C, SCN8A, TMED8, NSUN7, SLX4, MADD, DNLZ, PDE3B, UTY, DEPDC7, MTX1, MYO1E, RXRB, SYDE1, FN1, PUS7L, FYCO1, USP26, ACAP2, AHI1, KSR2, LMAN1, ZNF280D and SLC8A2 amongst others. Increases in mean precursor intensity in peptides from common plasma proteins such as ITIH3, SAA2, SAA1, and FN1 as well as cellular proteins such as COL24A1, POTEB, KANK1, SDCBP2, DNAH11, ADAMTS7, MLLT1, TTC21A, TSHR, SLX4, MTCH1, and PUS7L among others were associated with sepsis. The processing of SAA1 included the cleavage of the terminal peptide D/PNHFRPAGLPEKY from the most hydrophilic point of SAA1 on the COOH side of the cystatin C binding that was most apparent in ICU-Sepsis patients compared to all other diseases and controls. Additional cleavage of SAA1 on the NH2 terminus side of the cystatin binding site were observed in ICU-Sepsis. Thus there was disease associated variation in the processing of SAA1 in ICU-Sepsis versus ICU controls or other diseases and controls.

Conclusion

Specific proteins and peptides that vary between diseases might be discovered by the random and independent sampling of multiple disease and control plasma from different hospital and clinics by LC–ESI–MS/MS for storage in a relational SQL Server database and analysis with the R statistical system that will be a powerful tool for clinical research. The processing of SAA1 may play an unappreciated role in the inflammatory response to Sepsis.

Predictive model of return of spontaneous circulation among patients with out-of-hospital cardiac arrest in Thailand: The WATCH-CPR Score

BACKGROUND

Out-of-hospital cardiac arrest is an emergency that requires immediate management to save lives. However, some predictive scores for the immediate outcomes of patients with out-of-hospital cardiac arrest are difficult to use in clinical practice.

AIMS

This study aimed to identify predictors of sustained return of spontaneous circulation and to develop a predictive score.

METHODS

This prospective observational study evaluated sustained return of spontaneous circulation among out-of-hospital cardiac arrest patients in a Thai emergency department between July 2014 and March 2018. The baseline characteristics and prehospital and hospital findings were analysed.

RESULTS

Of 347 patients, 126 (36.3%) had sustained return of spontaneous circulation and 20 (5.8%) were discharged. Witnessed arrest (odds ratio = 2.9, 95% confidence interval 1.3-6.2), time from arrest to chest compression <15 min (odds ratio = 3.0, 95% confidence interval 1.3-7.0) and chest compression duration <30 min (odds ratio = 15.6, 95% confidence interval 8.7-28.0) predicted sustained return of spontaneous circulation; these were developed into the WATCH-CPR (Witnessed Arrest, Time from arrest to CHest compression-CPR duration) score. A score of ≥2 was optimal for predicting sustained return of spontaneous circulation, which provided an area under the receiver operating characteristic of 0.775 (95% confidence interval 0.724-0.825) and a sensitivity of 72.2% (95% confidence interval 63.4-79.6%) and specificity of 76.0% (95% confidence interval 69.8-81.4%).

CONCLUSIONS

The factors including witnessed arrest, time from arrest to chest compression and chest compression duration were developed as the WATCH-CPR score for predicting sustained return of spontaneous circulation among patients with out-of-hospital cardiac arrest.

Biomarkers in pediatric sepsis: a review of recent literature

Sepsis remains the leading cause of death in infants and children worldwide. Prompt diagnosis and monitoring of infection is pivotal to guide therapy and optimize outcomes. No single biomarker has so far been identified to accurately diagnose sepsis, monitor response and predict severity. We aimed to assess existing evidence of available sepsis biomarkers, and their utility in pediatric population. C-reactive protein and procalcitonin remain the most extensively evaluated and used biomarkers. However, biomarkers related to endothelial damage, vasodilation, oxidative stress, cytokines/chemokines and cell bioproducts have also been identified, often with regard to the site of infection and etiologic pathogen; still, with controversial utility. A multi-biomarker model driven by genomic tools could establish a personalized approach in future disease management.

Rapid, multiplexed detection of biomolecules using electrically distinct hydrogel beads

Rapid, low-cost, and multiplexed biomolecule detection is an important goal in the development of effective molecular diagnostics. Our recent work has demonstrated a microfluidic biochip device that can electrically quantitate a protein target with high sensitivity. This platform detects and quantifies a target analyte by counting and capturing micron-sized beads in response to an immunoassay on the bead surface. Existing microparticles limit the technique to the detection of a single protein target and lack the magnetic properties required for separation of the microparticles for direct measurements from whole blood. Here, we report new precisely engineered microparticles that achieve electrical multiplexing and adapt this platform for low-cost and label-free multiplexed electrical detection of biomolecules. Droplet microfluidic synthesis yielded highly-monodisperse populations of magnetic hydrogel beads (MHBs) with the necessary properties for multiplexing the electrical Coulter counting on chip. Each bead population was designed to contain a different amount of the hydrogel material, resulting in a unique electrical impedance signature during Coulter counting, thereby enabling unique identification of each bead. These monodisperse bead populations span a narrow range of sizes ensuring that all can be captured sensitively and selectively under simultaneously flow. Incorporating these newly synthesized beads, we demonstrate versatile and multiplexed biomolecule detection of proteins or DNA targets. This development of multiplexed beads for the electrical detection of biomolecules, provides a critical advancement towards multiplexing the Coulter counting approach and the development of a low cost point-of-care diagnostic sensor.

Biomarkers and newer laboratory investigations in the diagnosis of sepsis

Sepsis is a major cause of death in hospitalised patients accounting for mortality rates as high as 60% and, hence, is called 'a hidden public health disaster'. Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis is not a disease but is a clinical syndrome, where the initial features are nonspecific resulting in delayed diagnosis. Lack of specific laboratory tests to diagnose the syndrome adds to the diagnostic confusion. Failure to identify sepsis in the early stages itself delays effective treatment resulting in high morbidity and mortality. Various biomarkers and newer laboratory tests help to address these issues. However, to date there is no ideal test to diagnose sepsis. The most commonly used markers are C-reactive protein (CRP) and procalcitonin (PCT). There are around 180 biomarkers reported to be useful in sepsis. In addition to CRP and PCT, various emerging laboratory markers, such as like serum amyloid A, soluble triggering receptor expressed on myeloid cell-1, mannan and antimannan antibodies, and interferon γ inducible protein-10 etc., have been reviewed and their clinical usefulness discussed in this paper.

The value of biomarker-guided antibiotic therapy

INTRODUCTION

There is an increasing interest to individualize patient management and decisions regarding antibiotic treatment. Biomarkers may provide relevant information for this purpose.

AREAS COVERED

Despite a growing number of clinical trials investigating several biomarkers, there remain open questions regarding the best type of biomarker, timing or frequency of testing, and optimal cutoffs among others. The most promising results in regard to diagnosis of bacterial infection and therapy monitoring are found for procalcitonin (PCT), although some recent trials were not able to validate the promising earlier findings. Furthermore, less specific markers like C-reactive protein (CRP) and new prognostic biomarkers such as proadrenomedullin (MR-proADM) may improve the prognostic assessment of patients and proteomics may help shorten time to microbiological results. The aim of this review is to summarize the current concept of biomarker-guided management and provide an outlook of promising ongoing investigations.

EXPERT OPINION

'Antibiotic stewardship' is complex and needs more than just the measurement of one single biomarker. However, when integrated into the context of a thorough clinical examination, standard blood parameters and a well done risk stratification by clinical scores such as the SOFA-score, biomarkers have great potential to improve the diagnostic and prognostic assessment of patients.

Inhibition of neutrophil elastase prevents neutrophil extracellular trap formation and rescues mice from endotoxic shock

Neutrophil elastase (NE) is a serine protease stored in the azurophilic granules of neutrophils and released into the extracellular milieu during inflammatory response or formation of neutrophil extracellular traps (NETs). Neutrophils release NETs to entrap pathogens by externalizing their cellular contents in a DNA framework decorated with anti-microbials and proteases, including NE. Importantly, excess NETs in tissues are implicated in numerous pathologies, including sepsis, rheumatoid arthritis, vasculitis, and cancer. However, it remains unknown how to effectively prevent NET formation. Here, we show that NE plays a major role during NET formation and that inhibition of NE is a promising approach for decreasing NET-mediated tissue injury. NE promoted NET formation by human neutrophils. Whereas sivelestat, a small molecule inhibitor of NE, inhibited the formation of NETs in vitro , administration of free sivelestat did not have any efficacy in a murine model of lipopolysaccharide-induced endotoxic shock. To improve the efficacy of sivelestat in vivo, we have developed a nanoparticle system for delivering sivelestat. We demonstrate that nanoparticle-mediated delivery of sivelestat effectively inhibited NET formation, decreased the clinical signs of lung injury, reduced NE and other proinflammatory cytokines in serum, and rescued animals against endotoxic shock. Collectively, our data demonstrates that NE signaling can initiate NET formation and that nanoparticle-mediated inhibition of NE improves drug efficacy for preventing NET formation.

Role of the interferons in CD64 and CD169 expressions in whole blood: Relevance in the balance between viral- or bacterial-oriented immune responses

Introduction

CD64 expression increases on neutrophils during bacterial infections. Recently an increase in CD169 expression has been discovered on monocytes during viral infections. Generally, interferons α (IFNsα) and IFNsγ are key drivers of the infectious host immune response. The purpose of this study was to explore if a link exists between these IFNs and both biomarkers.

Methods

Whole blood samples from healthy volunteers were stimulated with either IFNs, interleukins, or infectious extracts, to mimic an infectious state. Expressions of CD64 and CD169 were assessed in these samples by multiple flow cytometry methods, over precise kinetics.

Results

The expression of CD64 was statistically higher in samples stimulated with IFNγ, and CD169 in those stimulated with IFNα (and all other type I IFNs). Surface expressions are directly induced by their respective IFNs via Janus kinase/signal transducer and activator of transduction pathways within 6 to 8 hours of incubation. Mixing both types of IFNs seemed to indicate that they partially inhibit each other.

Conclusions

The induction of CD169 on monocytes and CD164 on neutrophils by type I and type II IFNs confirms the relevance of these markers for assessing between a viral‐ vs bacterial‐oriented immune response.

Progranulin as a novel biomarker in diagnosis of early-onset neonatal sepsis

BACKGROUND

Infections are leading causes of morbidity and mortality in neonates and may also have severe long-term consequences. As early diagnosis of neonatal sepsis improves prognosis, identification of new or complementary biomarkers is of great importance. In this study, we have evaluated the diagnostic value of progranulin (PGRN) in early-onset neonatal sepsis (EOS) and compare its effectiveness with other commonly used biomarkers, such as procalcitonin (PCT) and C-reactive protein (CRP).

METHODS

A total of 121 infants with gestational age of >34 weeks admitted with suspected EOS were included in this study. Before initiating therapy, blood samples for whole blood count, CRP, PCT and PGRN were obtained from all neonates. Receiver-operating characteristic (ROC) curve and multivariate logistic regression analyses were performed.

RESULTS

Serum PGRN level of infected group was significantly higher than uninfected group (median 47.72 vs. 37.86 ng/ml, respectively; Mann-Whitney p < 0.0001). The ROC area under the curve (AUC) was 0.786 [95% confidence interval (CI) 0.706-0.867; p < 0.0001] for PGRN, 0.699 (95% CI 0.601-0.797; p = 0.0001) for age adjusted PCT, and 0.673 (95% CI 0.573-0.773; p = 0.0007) for CRP. With a cut-off value of 37.89 ng/ml, the diagnostic sensitivity and negative predictive value of PGRN were 94.34% and 91.7%, respectively. PGRN could significantly predict EOS independently of PCT (p < 0.0001), and the combined use of PGRN and PCT could significantly improve diagnostic performance for EOS (0.806; 95% CI 0.73-0.88; p < 0.0001), with a specificity of 89.06% and a positive predictive value of 81.10%.

CONCLUSIONS

PGRN may be used as a promising biomarker for the diagnosis of EOS, and the combined use of PGRN and PCT could improve the diagnosis of sepsis.

Diagnostic value of serum soluble triggering expressed receptor on myeloid cells 1 (sTREM-1) in suspected sepsis: a meta-analysis

Background

We aim to synthesize the up-to-date studies to investigate the diagnostic value of serum soluble triggering expressed receptor on myeloid cells 1 (sTREM-1) in suspected sepsis.

Results

A total of 19 studies with 2418 patients were finally enrolled in the meta-analysis. The pooled sensitivity was 0.82 (95% CI 0.73 to 0.89), specificity 0.81 (95% CI 0.75 to 0.86), positive likelihood ratio 4.3 (95% CI 3.02 to 6.12), negative likelihood ratio 0.22 (95% CI 0.24 to 0.35), diagnostic odds ratio 20 (95% CI 9 to 41) and AuROC 0.88 (95% CI 0.85 to 0.91). The meta-regression analysis revealed that the sample size, reference standard description, prevalence of sepsis in the trials and consecution of patient recruitment might be the source of heterogeneity.

Conclusions

The serum sTREM-1 had a moderate ability in diagnosis in suspected sepsis based on the current studies. However, more large-scale studies were needed to further evaluate the diagnostic accuracy of sTREM-1.

Effect of neutrophil CD64 for diagnosing sepsis in emergency department

BACKGROUND

The aim of this study is to investigate the diagnostic and prognostic value of neutrophil CD64 (nCD64) as a novel biomarker in sepsis patients.

METHODS

One hundred fifty-one adult patients diagnosed with sepsis and 20 age-matched healthy controls were enrolled in the study. Patients with sepsis were further subdivided into a sepsis group and a septic shock group. nCD64 expression, serum procalcitonin (PCT) level, C-reactive protein (CRP) level, and white blood cell (WBC) count were obtained for each patient, and Sequential Organ Failure Assessment (SOFA) scores were calculated.

RESULTS

nCD64 expression was higher in the sepsis group with confirmed infection than in the control group. The receiver operating characteristic (ROC) curve of nCD64 was higher than those of SOFA score, PCT, CRP and WBC for diagnosing infection. The area under the curve (AUC) of nCD64 combined with SOFA score was the highest for all parameters. The AUC of nCD64 for predicting 28-day mortality in sepsis was significantly higher than those of PCT, CRP, and WBC, but slightly lower than that of SOFA score. The AUC of nCD64 or PCT combined with SOFA score was significantly higher than that of any single parameter for predicting 28-day mortality.

CONCLUSION

nCD64 expression and SOFA score are valuable parameters for early diagnosis of infection and prognostic evaluation of sepsis patients.

Infection-induced innate antimicrobial response disorders: from signaling pathways and their modulation to selected biomarkers

Severe infections are a major public health problem responsible for about 40-65% of hospitalizations in intensive care units (ICU). The high mortality (30-50%) of persons diagnosed with severe infection is caused by largely unknown mechanisms of sepsis-induced immune system response. Severe infections with dynamic progress are accompanied with SIRS (systemic inflammatory reaction syndrome) and CARS (compensatory anti-inflammatory response syndrome), and require a biological treatment appropriate to the phase of immune response. The mechanisms responsible for severe infection related to immune system response particularly attract extensive interest of non-specific defense mechanisms, including signaling pathways of Toll-like receptors (mainly TLR4 and TLR2) that recognize distinct pathogen-associated molecular patterns (PAMP) and play a critical role in innate immune response. There are attempts of treatment, followed by blocking ligand binding with TLR or modulation of intracellular signaling pathways, to inhibit signal transduction. Moreover, researches regarding new and more efficient diagnostics biomarkers were mostly focused on indicators related to innate response to infection as well as connections of pro-inflammatory response with anti-inflammatory response.According to these studies, in case of ICU septic patients with high-risk of mortality, the solution for the problem will require mainly early immune and genetic diagnostics (e.g. cytokines, microRNA, cluster of differentiation-64 [CD64], triggering receptor expressed on myeloid cells-1 [TREM-1], and high mobility group box 1 protein [HMGB1]).

The History of Biomarkers: How Far Have We Come?

Sepsis is one of the oldest and most elusive syndromes in medicine that is still incompletely understood. Biomarkers may help to transform sepsis from a physiologic syndrome to a group of distinct biochemical disorders. This will help to differentiate between systemic inflammation of infectious and noninfectious origin and aid therapeutic decision making, hence improve the prognosis for patients, guide antimicrobial therapy, and foster the development of novel adjunctive sepsis therapies. To reach this goal requires increased systematic investigation that includes twenty-first century scientific approaches and technologies and appropriate clinical evaluation.

The diagnostic roles of neutrophil in bloodstream infections

Bloodstream infections remain a leading cause of death worldwide, despite advances in critical care and understanding of the pathophysiology and treatment strategies. No specific biomarkers or therapy are available for these conditions. Neutrophils play a critical role in controlling infection and it is suggested that their migration and antimicrobial activity are impaired during sepsis which contribute to the dysregulation of immune responses. Recent studies further demonstrated that interruption or reversal of the impaired migration and antimicrobial function of neutrophils improves the outcome of sepsis in animal models. In this review, we provide an overview of the associated diagnostic biomarkers involved neutrophils in sepsis, and discuss the potential of neutrophils as a target to specifically predict the outcome of sepsis.

Clinical research assessment by flow cytometry of biomarkers for infectious stratification in an Emergency Department

Aim: Management of patients with infections within the Emergency Department (ED) is challenging for practitioners, as the identification of infectious causes remains difficult with current techniques. A new combination of two biomarkers was tested with a new rapid flow cytometry technique. Materials & methods: Subjects from the ED were tested for their CD64 on neutrophils (nCD64) and CD169 on monocytes (mCD169) levels and results were compared to their clinical records. Results: Among 139 patients, 29% had confirmed bacterial infections and 5% viral infections. nCD64 and mCD169 respectively showed 88 and 86% sensitivity and 90 and 100% specificity for identifying subjects in bacterial or viral conditions. Conclusion: This point-of-care technique could allow better management of patients in the ED.

Anemia measurements to distinguish between viral and bacterial infections in the emergency department

The clinical diagnosis of acute infections in the emergency department is a challenging task due to the similarity in symptom presentation between virally and bacterially infected individuals, while the use of routine laboratory tests for pathogen identification is often time-consuming and may contain contaminants. We investigated the ability of various anemia-related parameters, including hemoglobin, red cell distribution width (RDW), and iron, to differentiate between viral and bacterial infection in a retrospective study of 3883 patients admitted to the emergency department with a confirmed viral (n = 1238) or bacterial (n = 2645) infection based on either laboratory tests or microbiological cultures. The ratio between hemoglobin to RDW was found to be significant in distinguishing between virally and bacterially infected patients and outperformed other anemia measurements. Moreover, the predictive value of the ratio was high even in patients presenting with low C-reactive protein values (< 21 mg/L). We followed the dynamics of hemoglobin, RDW, and the ratio between them up to 72 h post emergency department admission, and observed a consistent discrepancy between virally and bacterially infected patients over time. Additional analysis demonstrated higher levels of ferritin and lower levels of iron in bacterially infected compared with virally infected patients. The anemia measurements were associated with length of hospital stay, where all higher levels, except for RDW, corresponded to a shorter hospitalization period. We highlighted the importance of various anemia measurements as an additional host-biomarker to discern virally from bacterially infected patients.

Toward Early Diagnosis of Late-Onset Sepsis in Preterm Neonates: Dual Magnetoimmunosensor for Simultaneous Procalcitonin and C-Reactive Protein Determination in Diagnosed Clinical Samples

Early diagnosis of sepsis, combining blood cultures and inflammation biomarkers, continues to be a challenge, especially in very low birth weight (VLBW) infants because of limited availability of blood samples. Traditional diagnostic procedures are cumbersome, not fast enough, and require relatively large volumes of sample. Empiric use of antibiotics, before diagnostic confirmation, is required to decrease mortality, leading to potential antibiotic resistance and side effects in VLBW infants. To solve such a serious problem, a dual magnetoimmunosensor is proposed for simultaneous assessment of two of the most important sepsis biomarkers: procalcitonin (PCT for early phase) and C-reactive protein (CRP for late phase). This "sample-to-result" approach exhibited excellent sensitivity, selectivity, precision, and stability using low sample volumes (<30 μL) and under 20 min of total assay. The analytical usefulness of the approach was demonstrated by analyzing clinically relevant samples of preterm neonates with suspicion of sepsis.

Biomarkers in Pneumonia-Beyond Procalcitonin

Pneumonia is the leading infectious cause of mortality worldwide and one of the most common lower respiratory tract infections that is contributing significantly to the burden of antibiotic consumption. Due to the complexity of its pathophysiology, it is widely accepted that clinical diagnosis and prognosis are inadequate for the accurate assessment of the severity of the disease. The most challenging task for a physician is the risk stratification of patients with community-acquired pneumonia. Herein, early diagnosis is essential in order to reduce hospitalization and mortality. Procalcitonin and C-reactive protein remain the most widely used biomarkers, while interleukin 6 has been of particular interest in the literature. However, none of them appear to be ideal, and the search for novel biomarkers that will most sufficiently predict the severity and treatment response in pneumonia has lately intensified. Although our insight has significantly increased over the last years, a translational approach with the application of genomics, metabolomics, microbiomics, and proteomics is required to better understand the disease. In this review, we discuss this rapidly evolving area and summarize the application of novel biomarkers that appear to be promising for the accurate diagnosis and risk stratification of pneumonia.

A Novel Combination of Biomarkers to Herald the Onset of Sepsis Prior to the Manifestation of Symptoms

Sepsis, which kills over 200,000 patients and costs over $20 billion in the United States alone, presents a constant but preventable challenge in the healthcare system. Among the more challenging problems that it presents is misdiagnosis due to conflation with other inflammatory processes, as its mechanisms are identical to those of other inflammatory states. Unfortunately, current biomarker tests can only assess the severity and mortality risk of each case, whereas no single test exists that can predict sepsis prior to the onset of symptoms for the purpose of pre-emptive care and monitoring. We propose that a single test utilizing three, rather than two, biomarkers that appear most quickly in the blood and are the most specific for sepsis rather than trauma, may improve diagnostic accuracy and lead to lessened patient morbidity and mortality. Such a test would vastly improve patient outcomes and quality of life, prevent complications for sepsis survivors, and prevent hospital readmissions, saving the American healthcare system money. This review summarizes the current use of sepsis biomarkers to prognosticate morbidity and mortality, and rejects the current single-biomarker and even combination biomarker tests as non-specific and inaccurate for current patient needs/pro-inflammatory cytokines, general markers of inflammation, and proteins specific to myeloid cells (and therefore to infection) are discussed. Ultimately, the review suggests a three-biomarker test of procalcitonin (PCT), interleukin-6 (IL-6), and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) to diagnose sepsis before the onset of symptoms.

Automated measurement of neutrophil CD64 expression for diagnosing sepsis in critically ill patients

BACKGROUND

Although early identification of sepsis improves outcome, prompt and correct diagnostic remains often challenging. The expression of the high affinity immunoglobulin-Fc fragment receptor I CD64 on neutrophils is upregulated during acute inflammation. We here aimed at determining the usefulness of its rapid measurement in diagnosing sepsis.

METHODS

Seventy-two consecutive patients were enrolled upon admission to Intensive Care Unit within a two-month period. Sequential determination of serum C-reactive protein (CRP) and procalcitonin (PCT) concentrations was obtained. The neutrophil CD64 index was measured using Accellix-CD64® device, an in vitro diagnosis system allowing for an automatic and standardized measure.

RESULTS

Serum concentrations of CRP and PCT as well as the neutrophil CD64 index were higher in septic patients compared to all others (P<0.05 for the three markers). Only CD64 index was an independent predictor of sepsis, though with modest sensitivity and specificity (78% and 70%, respectively). Repeat determination of CD64 index at day 2 correctly classified 85% of patients.

CONCLUSIONS

This prospective study demonstrates the moderate performance of the neutrophil CD64 index, assessed through the Accellix-CD64® device, in diagnosing sepsis in the critically ill patient. However, repeat measurements improve its accuracy and may help to predict ICU-acquired infections.

Profile of the SeptiCyte™ LAB gene expression assay to diagnose infection in critically ill patients

Sepsis is a severe and frequently occurring clinical syndrome, caused by the inflammatory response to infections. Recent studies on the human transcriptome during sepsis have yielded several gene-expression assays that might assist physicians during clinical assessment of patients suspected of sepsis. SeptiCyte™ LAB (Immunexpress, Seattle, WA) is the first gene expression assay that was cleared by the FDA in the United States to distinguish infectious from non-infectious causes of systemic inflammation in critically ill patients. The test consists of the simultaneous amplification of four RNA transcripts (CEACAM4, LAMP1, PLAC8, and PLA2G7) in whole blood using a quantitative real-time PCR reaction. This review provides an overview of the challenges in the diagnosis of sepsis, the development of gene expression signatures, and a detailed description of available clinical performance studies evaluating SeptiCyte™ LAB.

The Systemic Lupus Erythematosus Infection Predictive Index (LIPI): A Clinical-Immunological Tool to Predict Infections in Lupus Patients

Among autoimmune diseases, systemic lupus erythematosus (SLE) patients have a unique predisposition to develop infections, which represents one of their main causes of morbidity and mortality. Many infections occur at disease diagnosis in the absence of immunosuppressive therapy, suggesting that the immunological abnormalities in SLE patients might be fundamental for the development of this complication. The aim of this study was to address the main clinical and immunological features associated with the development of infection and to create and validate a compound clinical-immunological infection predictive index in a cohort of SLE patients. We included 55 SLE patients with < 5 years since diagnosis. The clinical and immunological features were evaluated periodically and patients were followed-up during 1 year, searching for the development of infection. Immunophenotyping was performed by multiparametric flow cytometry and neutrophil extracellular traps (NETs) were assessed by confocal microscopy. Eighteen patients (32.7%) presented 19 infectious events, 5 (26.3%) were severe. For the construction of the index, we performed a logistic regression analysis and the cutoff points were determined with ROC curves. Increased numbers of peripheral Th17 cells, B cell lymphopenia, and lower TLR2 expression in monocytes, as well as the use of cyclophosphamide were the major risk factors for the development of infection and thus were included in the index. Besides, patients that developed infection were characterized by increased numbers of low-density granulocytes (LDGs) and higher expression of LL-37 in NETs upon infection. Finally, we validated the index retrospectively in a nested case-control study. A score >1.5 points was able to predict infection in the following year (AUC = 0.97; LR- = 0.001, specificity 100%, P = 0.0003). Our index encompasses novel immunological features able to prospectively predict the risk of infection in SLE patients.

Sepsis Biomarkers

Sepsis-related biomarkers have a variety of potential applications. The most well-known application is to differentiate patients with signs of systemic inflammation caused by infection, from those with systemic inflammation due to a non-infectious cause. This application is important for timely and judicious prescription of antibiotics. Apart from diagnostic applications, biomarkers can also be used to identify patients with sepsis who are at risk for poor outcome and to subgroup patients with sepsis based on biological commonalities. The latter two applications embody the concepts of prognostic and predictive enrichment, which are fundamental to precision medicine. This review will elaborate on these concepts, provide relevant examples, and discuss important considerations in the process of biomarkers discovery and development.

Comparison of the accuracy of neutrophil CD64, procalcitonin, and C-reactive protein for sepsis identification: a systematic review and meta-analysis

Background

Neutrophil CD64 is widely described as an accurate biomarker for the diagnosis of infection in patients with septic syndrome. We performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of neutrophil CD64, comparing it with C-reactive protein (CRP) and procalcitonin (PCT) for the diagnosis of infection in adult patients with septic syndrome, based on sepsis-2 criteria. We searched the PubMed and Embase databases and Google Scholar. Original studies reporting the performance of neutrophil CD64 for sepsis diagnosis in adult patients were retained. The pooled sensitivity, specificity, diagnostic odds ratio (DOR), and hierarchical summary receiver operating characteristic (SROC) curve were calculated.

Results

We included 14 studies (2471 patients) from 2006 to 2017 in the meta-analysis. The pooled sensitivity and specificity of neutrophil CD64 for diagnosing infection in adult patients with septic syndrome were 0.87 (95% CI 0.80–0.92) and 0.89 (95% CI 0.82–0.93), respectively. The area under the SROC curve and the DOR were 0.94 (95% CI 0.92–0.96) and 53 (95% CI 22–128), respectively. There was significant heterogeneity between the studies included. Subgroup analyses showed that this heterogeneity was due to differences in sample size and the proportions of patients with sepsis included in the studies. Six studies (927 patients) compared neutrophil CD64 and CRP determinations, and six studies (744 patients) compared neutrophil CD64 and PCT determinations. The area under the SROC curve was larger for neutrophil CD64 than for CRP (0.89 [95% CI 0.87–0.92] vs. 0.84 [95% CI 0.80–0.88], P < 0.05) or PCT (0.89 [95% CI 0.84–0.95] vs. 0.84 [95% CI 0.79–0.89], P < 0.05).

Conclusions

In adult patients with septic syndrome, neutrophil CD64 levels are an excellent biomarker with moderate accuracy outperforming both CRP and PCT determinations.

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0479-2) contains supplementary material, which is available to authorized users.

[Inflammatory markers in diagnosis and prognosis of abdominal sepsis]

For today, it is necessary to recognize, that treatment of patients with abdominal sepsis remains the basic problem in urgent surgery due to the invariably high mortality. Early diagnostics and targeted therapy are the key points for improving of sepsis outcome. At present, researchers around the world have proposed a large number of biological markers for diagnosing sepsis and predicting mortality. Ideally, doctors can use biomarkers for risk stratification, diagnosing, monitoring of treatment effectiveness and outcome prediction. The biomarker is a laboratory parameter that can be objectively measured and characterized as an indicator of normal and pathological biological processes. The article presents the modern concept of the sepsis pathogenesis for understanding the role of various biomarkers and inflammatory indicators in its development. We have analyzed literature data and summarized information on the possible use of biological markers and their combinations in the early detection of sepsis, for monitoring sepsis and predicting its outcome.

Gut Microbiota Disruption in Septic Shock Patients: A Pilot Study

BACKGROUND The composition of the intestinal microbiota and its effect on septic shock patients in the intensive care unit (ICU) is unknown. In the present study we explored the hypothesis that bacterial diversity is decreased in septic shock patients and that this diversity may be improved by use of probiotics or enteral nutrition. MATERIAL AND METHODS A total of 15 stool samples were collected prospectively from septic shock patients in the ICU, while 15 samples from healthy subjects served as controls. Bacterial DNA was submitted for 16S rDNA gene sequencing. The relationship between intestinal microbiota and prognosis was evaluated. RESULTS Significantly lower bacterial diversity was found in septic shock patients compared with healthy subjects (p<0.05). However, there was no difference in bacterial diversity in the presence or absence of probiotics (p=0.59), enteral nutrition (p=0.59), or in-hospital death (p=0.93) in septic shock patients. A high abundance of Proteobacteria and Fusobacteria was observed in most septic shock patients, whereas low abundance was observed in healthy subjects (mean relative proportion: 23.71% vs. 3.53%, p<0.05; 1.27% vs. 0.12%, p=0.59). CONCLUSIONS Bacterial diversity was decreased, and 1 or 2 rare bacterial species were overgrown in septic shock patients. Bacterial diversity was not improved by use of probiotics or enteral nutrition. The small sample size of our study limits the interpretation of results.

Interleukin-27 as a candidate diagnostic biomarker for bacterial infection in immunocompromised pediatric patients

Background

Immunocompromised pediatric patients constitute a growing population that is particularly vulnerable to bacterial infection, necessitating prompt recognition and treatment. This study assessed the utility of interleukin-27 (IL-27) and procalcitonin (PCT) as biomarkers of bacterial infection among immunocompromised pediatric subjects.

Methods

This is a single-center prospective cohort study conducted from July 2016 through September 2017, drawing subjects from the inpatient units at Cincinnati Children’s Hospital Medical Center (CCHMC), a large, tertiary care children’s hospital. Patients were included if they fit the definition of immunocompromised and were under clinical suspicion for infection, defined by the acquisition of a blood culture at any point during the admission. The primary analysis assessed the accuracy of IL-27 to diagnose bacterial infection in immunocompromised pediatric patients, using PCT as a comparator.

Results

293 patients were recruited, representing 400 episodes of suspected bacterial infection. The median age was 7.8 years (IQR 3.1–13.8 years). Fifty-three percent (n = 213) of the population had a primary oncologic diagnosis, 24% (n = 95) had received a bone marrow transplant, and 21% (n = 85) had received a solid organ transplant. The overall infection rate was 37%, with 70% of those patients having some form of culture positivity. Twenty-eight-day mortality was 5%, 60-day mortality was 9%, with 87% of patients surviving to hospital discharge. The AUC’s of the ROC curve to diagnose bacterial infection were 0.62 (0.5–0.68) for IL-27 and 0.65 (0.6–0.73) for PCT. Using the previously determined cutoff of 5.0 ng/mL, the specificity of IL-27 to diagnose bacterial infection reached 94%, with a negative predictive value of 64%.

Conclusions

Despite prior work demonstrating IL-27 and PCT as possible biomarkers of bacterial infection in immunocompromised pediatric patients, we were unable to validate these findings. This illustrates the challenges associated with developing reliable biomarkers of bacterial infection in this vulnerable population.

Neutrophil-to-Lymphocyte Ratio, Monocyte-to-Lymphocyte Ratio, Platelet-to-Lymphocyte Ratio, and Mean Platelet Volume-to-Platelet Count Ratio as Biomarkers in Critically Ill and Injured Patients: Which Ratio to Choose to Predict Outcome and Nature of Bacteremia?

Background

Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), and mean platelet volume-to-platelet count (MPV/PC) ratio are readily available parameters that might have discriminative power regarding outcome. The aim of our study was to assess prognostic value of these biomarkers regarding outcome in critically ill patients with secondary sepsis and/or trauma.

Methods

A total of 392 critically ill and injured patients, admitted to surgical ICU, were enrolled in a prospective observational study. Leukocyte and platelet counts were recorded upon fulfilling Sepsis-3 criteria and for traumatized Injury Severity Score > 25 points. Patients were divided into four subgroups: peritonitis, pancreatitis, trauma with sepsis, and trauma without sepsis.

Results

NLR and MPV/PC levels were significantly higher in nonsurvivors (AUC/ROC of 0.681 and 0.592, resp., in the peritonitis subgroup; 0.717 and 0.753, resp., in the pancreatitis subgroup); MLR and PLR did not differ significantly. There was no significant difference of investigated biomarkers between survivors and nonsurvivors in trauma patients with and without sepsis except for PLR in the trauma without sepsis subgroup (significantly higher in nonsurvivors, AUC/ROC of 0.719). Independent predictor of lethal outcome was NLR in the whole cohort and in the peritonitis subgroup as well as MPV in the pancreatitis subgroup. Also, there were statistically significant differences in MPV/PC, MLR, and PLR values regarding nature of bacteremia. In general, the lowest levels had been found in patients with Gram-positive blood cultures.

Conclusions

NLR and MPV were very good independent predictors of lethal outcome. For the first time, we demonstrate that nature of bacteremia influences MPV/PC, MLR, and PLR. In heterogeneous cohort subgroup, analysis is essential.

Circulating biomarkers may be unable to detect infection at the early phase of sepsis in ICU patients: the CAPTAIN prospective multicenter cohort study

PURPOSE

Sepsis and non-septic systemic inflammatory response syndrome (SIRS) are the same syndromes, differing by their cause, sepsis being secondary to microbial infection. Microbiological tests are not enough to detect infection early. While more than 50 biomarkers have been proposed to detect infection, none have been repeatedly validated.

AIM

To assess the accuracy of circulating biomarkers to discriminate between sepsis and non-septic SIRS.

METHODS

The CAPTAIN study was a prospective observational multicenter cohort of 279 ICU patients with hypo- or hyperthermia and criteria of SIRS, included at the time the attending physician considered antimicrobial therapy. Investigators collected blood at inclusion to measure 29 plasma compounds and ten whole blood RNAs, and-for those patients included within working hours-14 leukocyte surface markers. Patients were classified as having sepsis or non-septic SIRS blindly to the biomarkers results. We used the LASSO method as the technique of multivariate analysis, because of the large number of biomarkers.

RESULTS

During the study period, 363 patients with SIRS were screened, 84 having exclusion criteria. Ninety-one patients were classified as having non-septic SIRS and 188 as having sepsis. Eight biomarkers had an area under the receiver operating curve (ROC-AUC) over 0.6 with a 95% confidence interval over 0.5. LASSO regression identified CRP and HLA-DRA mRNA as being repeatedly associated with sepsis, and no model performed better than CRP alone (ROC-AUC 0.76 [0.68-0.84]).

CONCLUSIONS

The circulating biomarkers tested were found to discriminate poorly between sepsis and non-septic SIRS, and no combination performed better than CRP alone.

Role of TREM-1 in pulmonary tuberculosis patients- analysis of serum soluble TREM-1 levels

Triggering receptor expressed on myeloid cells 1 (TREM-1) amplifies inflammatory responses and is upregulated during sepsis and pulmonary infection. The association between serum soluble TREM-1 (sTREM-1) level and pulmonary tuberculosis (PTB) disease deserves investigation. In the present study, patients with PTB, latent TB infection (LTBI), and non-TB, non-LTBI subjects were prospectively enrolled and serum levels of sTREM-1, sTREM-2, and C-reactive protein (CRP) were measured. We correlated serum biomarkers and clinical presentations and treatment outcomes of PTB cases. We also utilized immunohistochemistry (IHC) to visualize TREM-1-expressing cells in lung tissues from PTB patients. A total of 86 PTB, 41 LTBI, and 20 non-TB, non-LTBI subjects were enrolled. Serum levels of sTREM-1 and CRP significantly increased in PTB patients; these higher serum levels were correlated with more advanced involvement in chest films and higher bacteria burden in sputum. In multivariate analysis, serum levels of sTREM-1 >260 pg/mL and CRP >2.6 mg/L were independent predictors for on-treatment mortality. Abundant TREM-1-expressing macrophages were identified in lung tissues from PTB samples. In conclusion, serum levels of sTREM-1 correlated with disease severity and treatment outcomes in PTB patients.

Checking procalcitonin suitability for prognosis and antimicrobial therapy monitoring in burn patients

Background

Due to greater infection susceptibility, sepsis is the main cause of death in burn patients. Quick diagnosis and patient stratification, early and appropriated antimicrobial therapy, and focus control are crucial for patients' survival. On the other hand, superfluous extension of therapy is associated with adverse events and arousal of microbial resistance. The use of biomarkers, necessarily coupled with close clinical examination, may predict outcomes, stratifying patients who need more intensive care, and monitor the efficacy of antimicrobial therapy, allowing faster de-escalation or stop, reducing the development of resistance and possibly the financial burden, without increasing mortality. The aim of this work is to check the suitability of procalcitonin (PCT) to fulfill these goals in a large sample of septic burn patients.

Methods

One hundred and one patients, with 15% or more of total body surface area (TBSA) burned, admitted from January 2011 to December 2014 at Coimbra Burns Unit (CBU), in Portugal were included in the sample. All patients had a diagnosis of sepsis, according to the American Burn Association (ABA) criteria. The sample was factored by survival (68 survivors and 33 non-survivors). The maximum value of PCT in each day was used for statistical analysis. Data were summarized by location measures (mean, median, minimum, maximum, quartiles) and dispersion measures (standard error and range measures). Statistical analysis was performed with SPSS© 23.0 IBM© for Windows©.

Results

There were statistically significant differences between PCT levels of patients from the survivor and non-survivor groups during the first and the last weeks of hospitalization as well as during the first week after sepsis suspicion, being slightly higher during this period. During the first 7 days of antimicrobial therapy, PCT was always higher in the non-survivor, still without reaching statistical significance, but when the analysis was extended till the 15th day, PCT increased significantly, rapidly, and steadily, denouncing therapy failure.

Conclusion

Despite being not an ideal biomarker, PCT proved to have good prognostic power in septic burn patients, paralleling the evolution of the infectious process and reflecting the efficacy of antimicrobial therapy, and the inclusion of its serial dosing may be advised to reinforce antimicrobial stewardship programs at burn units; meanwhile, more accurate approaches are not available.

The clinical role of microRNA-21 as a promising biomarker in the diagnosis and prognosis of colorectal cancer: a systematic review and meta-analysis

This systematic analysis aimed to investigate the value of microRNA-21 (miR-21) in colorectal cancer for multiple purposes, including diagnosis and prognosis, as well as its predictive power in combination biomarkers. Fifty-seven eligible studies were included in our meta-analysis, including 25 studies for diagnostic meta-analysis and 32 for prognostic meta-analysis. For the diagnostic meta-analysis of miR-21 alone, the overall pooled results for sensitivity, specificity, and area under the curve (AUC) were 0.64 (95% CI: 0.53-0.74), 0.85 (0.79-0.90), and 0.85 (0.81-0.87), respectively. Circulating samples presented corresponding values of 0.72 (0.63-0.79), 0.84 (0.78-0.89), and 0.86 (0.83-0.89), respectively. For the diagnostic meta-analysis of miR-21-related combination biomarkers, the above three parameters were 0.79 (0.69-0.86), 0.79 (0.68-0.87), and 0.86 (0.83-0.89), respectively. Notably, subgroup analysis suggested that miRNA combination markers in circulation exhibited high predictive power, with sensitivity of 0.85 (0.70-0.93), specificity of 0.86 (0.77-0.92), and AUC of 0.92 (0.89-0.94). For the prognostic meta-analysis, patients with higher expression of miR-21 had significant shorter disease-free survival [DFS; pooled hazard ratio (HR): 1.60; 95% CI: 1.20-2.15] and overall survival (OS; 1.54; 1.27-1.86). The combined HR in tissues for DFS and OS were 1.76 (1.31-2.36) and 1.58 (1.30-1.93), respectively. Our comprehensive systematic review revealed that circulating miR-21 may be suitable as a diagnostic biomarker, while tissue miR-21 could be a prognostic marker for colorectal cancer. In addition, miRNA combination biomarkers may provide a new approach for clinical application.

Towards precision medicine in sepsis: a position paper from the European Society of Clinical Microbiology and Infectious Diseases

BACKGROUND

Our current understanding of the pathophysiology and management of sepsis is associated with a lack of progress in clinical trials, which partly reflects insufficient appreciation of the heterogeneity of this syndrome. Consequently, more patient-specific approaches to treatment should be explored.

AIMS

To summarize the current evidence on precision medicine in sepsis, with an emphasis on translation from theory to clinical practice. A secondary objective is to develop a framework enclosing recommendations on management and priorities for further research.

SOURCES

A global search strategy was performed in the MEDLINE database through the PubMed search engine (last search December 2017). No restrictions of study design, time, or language were imposed.

CONTENT

The focus of this Position Paper is on the interplay between therapies, pathogens, and the host. Regarding the pathogen, microbiologic diagnostic approaches (such as blood cultures (BCs) and rapid diagnostic tests (RDTs)) are discussed, as well as targeted antibiotic treatment. Other topics include the disruption of host immune system and the use of biomarkers in sepsis management, patient stratification, and future clinical trial design. Lastly, personalized antibiotic treatment and stewardship are addressed (Fig. 1).

IMPLICATIONS

A road map provides recommendations and future perspectives. RDTs and identifying drug-response phenotypes are clear challenges. The next step will be the implementation of precision medicine to sepsis management, based on theranostic methodology. This highly individualized approach will be essential for the design of novel clinical trials and improvement of care pathways.

Neutrophil CD64 expression, procalcitonin and presepsin are useful to differentiate infections from flares in SLE patients with SIRS

Background/Objective Differentiating systemic lupus erythematosus (SLE) activity from infections in febrile patients is difficult because of similar initial clinical presentation. The aim of this study is to evaluate the usefulness of a number of biomarkers for differentiating infections from activity in SLE patients admitted with systemic inflammatory response (SIRS). Methods Patients with SLE and SIRS admitted to the emergency room were included in this study. Measurements of different markers including procalcitonin, neutrophil CD64 expression and presepsin, were performed. Infection was considered present when positive cultures and/or polymerase chain reaction were obtained. Sensitivity and specificity were calculated for all biomarkers. Results Twenty-seven patients were admitted, 23 women (82.5%), mean age 33.2 years. An infectious disease was confirmed in 12 cases. Markers for SLE activity including anti-DNA titers by IIF ( p = 0.041) and enzyme-linked immunosorbent assay ( p = 0.009) were used for differentiating SLE flares from infection. On the contrary, increased procalcitonin ( p = 0.047), neutrophil CD64 expression by flow cytometry ( p = 0.037) and presepsin ( p = 0.037) levels were observed in infected SLE patients. Conclusions High neutrophil CD64 expression, presepsin and procalcitonin levels are useful to differentiate infections from activity in SLE patients. In most cases, a positive bioscore that includes these three markers demonstrate the presence of an infectious disease.

Time Course of CD64, a Leukocyte Activation Marker, During Cardiopulmonary Bypass Surgery

Distinction between inflammation secondary to surgery, especially coronary artery bypass graft with cardiopulmonary bypass (CPB), and inflammation due to infection is difficult in surgical intensive care unit (ICU) patients. Development of biomarkers of infection could help clinicians in the early identification and thus treatment of sepsis in these patients. We compared the time course of the neutrophil CD64 index, a high affinity immunoglobulin FC γ receptor I whose expression is increased in bacterial infection, in 39 patients undergoing cardiac surgery with CPB and 11 patients admitted to the ICU with severe sepsis or septic shock. The CD64 index was significantly more elevated in septic patients than in patients who had CPB except at day 5. The CD64 index increased moderately on day 1 after cardiac surgery but the value remained lower than in septic patients. The duration for which the CD64 index was greater than 1.0 was longer in septic than in CPB patients. Receiver operating curves to differentiate CPB from sepsis on day 1 were not significantly different between C-reactive protein (CRP) concentrations and CD 64 index. Nevertheless, combination of low CD64 index with low CRP concentrations on day 1 ruled out sepsis except in three patients. There were no correlations between the CD64 index and cytokine levels (tumor necrosis factor [TNF]-α, interferon [IFN]γ, interleukin [IL]-6, IL-10, IL-8, IL-12) measured in subpopulations. In conclusion, CD64 index only in combination with CRP concentrations could be used to discriminate inflammation due to surgery from that due to infection in this particular population.

The coming era of precision medicine for intensive care

Recent advances in technology and better understanding of mechanisms underlying disease are beginning to enable us to better characterize critically ill patients. Instead of using nonspecific syndromic groupings, such as sepsis or acute respiratory distress syndrome, we can now classify individual patients according to various specific characteristics, such as immune status. This "personalized" medicine approach will enable us to distinguish patients who have similar clinical presentations but different cellular and molecular responses that will influence their need for and responses (both negative and positive) to specific treatments. Treatments will be able to be chosen more accurately for each patient, resulting in more rapid institution of appropriate, effective therapy. We will also increasingly be able to conduct trials in groups of patients specifically selected as being most likely to respond to the intervention in question. This has already begun with, for example, some new interventions being tested only in patients with coagulopathy or immunosuppressive patterns. Ultimately, as we embrace this era of precision medicine, we may be able to offer precision therapies specifically designed to target the molecular set-up of an individual patient, as has begun to be done in cancer therapeutics.

Biomarkers in Sepsis

A biomarker is a characteristic by which a (patho)physiologic process can be identified. Biomarkers can be of diagnostic value (to discriminate infection from noninfectious conditions or to determine the causative pathogen), of prognostic value (assigning risk profiles and predict outcome), and in the future may be of theranostic value (aid in selection and monitoring of therapy). Systems biology provides a promising tool for the discovery of novel biomarkers. Biomarkers can be the key to personalized targeted treatment in the future clinical management of sepsis.

Combining Biomarkers with EMR Data to Identify Patients in Different Phases of Sepsis

Sepsis is a leading cause of death and is the most expensive condition to treat in U.S. hospitals. Despite targeted efforts to automate earlier detection of sepsis, current techniques rely exclusively on using either standard clinical data or novel biomarker measurements. In this study, we apply machine learning techniques to assess the predictive power of combining multiple biomarker measurements from a single blood sample with electronic medical record data (EMR) for the identification of patients in the early to peak phase of sepsis in a large community hospital setting. Combining biomarkers and EMR data achieved an area under the receiver operating characteristic (ROC) curve (AUC) of 0.81, while EMR data alone achieved an AUC of 0.75. Furthermore, a single measurement of six biomarkers (IL-6, nCD64, IL-1ra, PCT, MCP1, and G-CSF) yielded the same predictive power as collecting an additional 16 hours of EMR data(AUC of 0.80), suggesting that the biomarkers may be useful for identifying these patients earlier. Ultimately, supervised learning using a subset of biomarker and EMR data as features may be capable of identifying patients in the early to peak phase of sepsis in a diverse population and may provide a tool for more timely identification and intervention.

Neutrophil CD64, C-reactive protein, and procalcitonin in the identification of sepsis in the ICU - Post-test probabilities

PURPOSE

We were interested in whether C-reactive protein (CRP) and procalcitonin (PCT) distinguish sepsis from non-septic controls and whether a combination of CRP, PCT, and neutrophil CD64 improves identification of sepsis in the intensive care unit (ICU).

MATERIALS AND METHODS

We analyzed the CRP and PCT concentrations from 27 patients with sepsis and 15 ICU controls. In addition, CD64 on neutrophils was measured using quantitative flow cytometry. We present a multiple marker analysis for sepsis diagnostics combining neutrophil CD64, CRP, and PCT using post-test analysis.

RESULTS

The CRP and PCT values separated sepsis and non-septic ICU patients. In post-test analysis, CRP provided a positive probability of 0.48 and a negative probability of 0.053 for sepsis in the ICU; while, the corresponding values were 0.35 and 0.0059, respectively, for PCT and 0.62 and 0.0013, respectively, for neutrophil CD64. When neutrophil CD64 was analyzed with PCT and CRP, the probabilities were 0.98 and <0.001, respectively.

CONCLUSIONS

Neutrophil CD64 expression was superior to PCT and CRP for the identification of sepsis in ICU. Positive post-test probability for any combinations of simultaneously analyzed CRP, PCT and CD64 showed improved diagnostic accuracy for sepsis. This approach may be useful for guiding antibiotic treatment in ICU.

Assessment of thoracic ultrasound in complementary diagnosis and in follow up of community-acquired pneumonia (cap)

Background

Chest X-ray (CXR) is the primary diagnostic tool for community-acquired pneumonia (CAP). Some authors recently proposed that thoracic ultrasound (TUS) could valuably flank or even reliably substitute CXR in the diagnosis and follow-up of CAP. We investigated the clinical utility of TUS in a large sample of patients with CAP, to challenge the hypothesis that it may be a substitute for CXR.

Methods

Out of 645 consecutive patients with a CXR-confirmed CAP diagnosed in the emergency room of our hospital over a three-years period, 510 were subsequently admitted to our department of Internal Medicine. These patients were evaluated by TUS by a well-trained operator who was blinded of the initial diagnosis. TUS scans were performed both at admission and repeated at day 4-6th and 9-14th during stay.

Results

TUS identified 375/510 (73.5%) of CXR-confirmed lesions, mostly located in posterior-basal or mid-thoracic areas of the lungs. Pleural effusion was detected in 26.9% of patients by CXR and in 30.4% by TUS. TUS documented the change in size of the consolidated areas as follows: 6.3 ± 3.4 cm at time 0, 2.5 ± 1.8 at 4-6 d, 0.9 ± 1.4 at 9-14 d. Out of the 12 patients with delayed CAP healing, 7 of them turned out to have lung cancer.

Conclusions

TUS allowed to detect lung consolidations in over 70% of patients with CXR-confirmed CAP, but it gave false negative results in 26.5% of cases. Our longitudinal results confirm the role of TUS in the follow-up of detectable lesions. Thus, TUS should be regarded as a complementary and monitoring tool in pneumonia, instead of a primary imaging modality.