Interleukin-6, interleukin-8, and a rapid and sensitive assay for calcitonin precursors for the determination of bacterial sepsis in febrile neutropenic children

Biomarkers for the Prediction and Judgement of Sepsis and Sepsis Complications: A Step towards precision medicine?

Sepsis and septic shock are a major public health concern and are still associated with high rates of morbidity and mortality. Whilst there is growing understanding of different phenotypes and endotypes of sepsis, all too often treatment strategies still only employ a “one-size-fits-all” approach. Biomarkers offer a unique opportunity to close this gap to more precise treatment approaches by providing insight into clinically hidden, yet complex, pathophysiology, or by individualizing treatment pathways. Predicting and evaluating systemic inflammation, sepsis or septic shock are essential to improve outcomes for these patients. Besides opportunities to improve patient care, employing biomarkers offers a unique opportunity to improve clinical research in patients with sepsis. The high rate of negative clinical trials in this field may partly be explained by a high degree of heterogeneity in patient cohorts and a lack of understanding of specific endotypes or phenotypes. Moving forward, biomarkers can support the selection of more homogeneous cohorts, thereby potentially improving study conditions of clinical trials. This may finally pave the way to a precision medicine approach to sepsis, septic shock and complication of sepsis in the future.

Biomarkers for Diagnosing Febrile Illness in Immunocompromised Children: A Systematic Review of the Literature

OBJECTIVE

This study aims to assess the performance of biomarkers used for the prediction of bacterial, viral, and fungal infection in immunocompromised children upon presentation with fever.

METHODS

We performed a literature search using PubMed and MEDLINE and In-Process & Other Non-indexed Citations databases. Cohort and case-control studies assessing biomarkers for the prediction of bacterial, viral, or fungal infection in immunocompromised children vs. conventional microbiological investigations were eligible. Studies including adult patients were eligible if pediatric data were separately assessable. Data on definitions used for infections, fever, and neutropenia and predictive values were collected. Risk of bias was assessed with the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

RESULTS

Fifty-two studies involving 13,939 febrile episodes in 7,059 children were included. In total, 92.2% were in cancer patients (n = 48), and 15.7% also included hematopoietic stem cell transplantation patients (n = 8). Forty-three biomarkers were investigated, of which 6 (CRP, PCT, IL-8, IL-6, IL-10, and TNFα) were significantly associated with bacterial infection at admission, studied in multiple studies, and provided predictive data. Literature on the prediction of viral and fungal infection was too limited. Eight studies compared C-reactive protein (CRP) and procalcitonin (PCT), with PCT demonstrating superiority in 5. IL-6, IL-8, and IL-10 were compared with CRP in six, four, and one study, respectively, with mixed results on diagnostic superiority. No clear superior biomarker comparing PCT vs. IL-6, IL-8, or IL-10 was identified.

DISCUSSION

There is great heterogeneity in the biomarkers studied and cutoff values and definitions used, thus complicating the analysis. Literature for immunocompromised children with non-malignant disease and for non-bacterial infection is sparse. Literature on novel diagnostics was not available. We illustrated the challenges of diagnosing fever adequately in this study population and the need for improved biomarkers and clinical decision-making tools.

Update on Febrile Neutropenia in Pediatric Oncological Patients Undergoing Chemotherapy

Febrile neutropenia (FN) is a common complication of chemotherapy in oncological children and one of the most important causes of morbidity and mortality in these patients. The early detection of a bacteremia and the rapid therapeutic intervention are crucial to improve the outcome. We analyzed the literature in order to clarify the epidemiology of FN in children undergoing chemotherapy, the specific factors associated with a negative outcome, the most common etiology, and the value of biological markers as a tool to make an early diagnosis or to monitor the evolution of the infection. Several studies have tried to identify specific factors that could help the clinician in the detection of an infection and in its microbiological identification. However, due to the heterogenicity of the available studies, sufficient evidence is lacking to establish the role of these risk factors in clinical practice and future research on this topic appear mandatory. Determinations of risk factors, etiology, and markers of febrile episodes in these patients are complicated by the characteristics of the underlying illness and the effects of treatments received. Although some studies have tried to develop an evidence-based guideline for the empiric management of FN in pediatrics, validated predictive scores and algorithms are still lacking and urgently needed.

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.

Pro-inflammatory cytokine ratios determine the clinical course of febrile neutropenia in children receiving chemotherapy

Background

Febrile neutropenia is a common and serious complication during treatment of childhood cancer. Empirical broad-spectrum antibiotics are usually administered until neutrophil cell count recovery. It was the aim of this study to investigate cytokine profiles as potential biomarkers using in-vitro sepsis models to differentiate between distinct clinical courses of febrile neutropenia (FN).

Methods

We conducted an observational study in FN episodes of pediatric oncology patients. Courses of neutropenia were defined as severe in case of proven blood stream infection or clinical evidence of complicated infection. We collected blood samples at various time points from the onset of FN and stimulated ex vivo with lipopolysaccharide (LPS) and Staphylococcus epidermidis (SE) for 24 h. Twenty-seven cytokine levels were measured in the whole blood culture supernatants by a multiplex immunoassay system.

Results

Forty-seven FN episodes from 33 children were investigated. IL-8, IL-1β, and MCP-1 expression increased significantly over time. IL-8, MIP-1α, MIP-1β, MCP-1, and TNF-α showed significantly lower concentration in patients with a clinically severe course of the FN.

Conclusions

Distinct patterns of cytokine profiles seem to be able to determine infectious FN and to predict the severity of its clinical course. If these data can be verified in a multi-centre setting, this may finally lead to an individualized treatment strategy facilitating antibiotic stewardship in these patients.

Diagnostic Value of C-reactive Protein and Interleukin-8 in Risk Stratification of Febrile Neutropenic Children with Allogeneic Hematopoietic Stem Cell Transplantation

In this analysis, the levels of CRP and IL-8 were employed as a guide for designing the duration of antibiotics administration in the condition of febrile neutropenia. The importance of laboratory biomarkers is in the early diagnosis of critical illness and adjustment of further management. IL-8 is a useful biomarker for the early identification of critically ill patients, compared to CRP in FN.

Precision Immunotherapy for Sepsis

Decades of sepsis research into a specific immune system-targeting adjunctive therapy have not resulted in the discovery of an effective compound. Apart from antibiotics, source control, resuscitation and organ support, not a single adjunctive treatment is used in current clinical practice. The inability to determine the prevailing immunological phenotype of patients and the related large heterogeneity of study populations are regarded by many as the most important factors behind the disappointing results of past clinical trials. While the therapeutic focus has long been on immunosuppressive strategies, increased appreciation of the importance of sepsis-induced immunoparalysis in causing morbidity and mortality in sepsis patients has resulted in a paradigm shift in the sepsis research field towards strategies aimed at enhancing the immune response. However, similar to immunosuppressive therapies, precision medicine is imperative for future trials with immunostimulatory compounds to succeed. As such, identifying those patients with a severely suppressed or hyperactive immune system who will most likely benefit from either immunostimulatory or immunosuppressive therapy, and accurate monitoring of both the immune and treatment response is crucial. This review provides an overview of the challenges lying ahead on the path towards precision immunotherapy for patients suffering from sepsis.

Predictive value of PCT and IL-6 for bacterial infection in children with cancer and febrile neutropenia

Purpose

Only a third of children with cancer and febrile neutropenia (FN) have a proven bacterial infection; nevertheless, most children are hospitalized and treated with intravenous antibiotics. Several biomarkers have been proposed as predictive markers for bacterial infection in this population. We aimed to evaluate the role of interleukin-6 (IL-6) and procalcitonin (PCT) in diagnosing bacterial infection in children with cancer and FN.

Methods

The study population was derived from a prospective database (2006–2013, IL-8 study) comprising children with cancer who presented with FN. From stored plasma samples (taken at admission and/or at 12–24 h), we determined the PCT and IL-6 levels. Consequently, we explored their relation with the presence of bacterial infection (positive blood culture, radiologically documented infection or clinical bacterial focus). We predefined cutoff values at 60 ng/L for IL-6 and 0.25 ng/mL for PCT.

Results

Seventy-seven FN episodes in 55 children with cancer were included. In 18 episodes (23.4%), a bacterial infection was documented. Both at presentation and after 12–24 h, median values of IL-6 and PCT were significantly higher in patients with a bacterial infection compared to patients without a bacterial infection. With both biomarkers above cutoff values, sensitivity was 93% (with either one, this was even 100%). The identified group at low risk for bacterial infection comprised 41% of the population.

Conclusion

PCT and IL-6 are promising markers in identifying bacterial infection in children with cancer and FN. In a subsequent project, we will incorporate these biomarkers in a risk assessment model that we will test prospectively in a clinical trial.

Cytokine Kinetics in Febrile Neutropenic Children: Insights on the Usefulness as Sepsis Biomarkers, Influence of Filgrastim, and Behavior of the IL-23/IL-17 Pathway

Background

The study aimed to describe the kinetics of various cytokines from day 1 to day 14 of the onset of fever in neutropenic children and to evaluate their performances as discriminators of sepsis in the first 24 hours of fever, the possible influence of filgrastim, and the functioning of the IL-23/IL-17 axis.

Methods

IL-1β, TNF-α, IL-10, IL-12/23p40, IL-21, IL-6, IL-8, IL-17, G-CSF, and GM-CSF were measured in plasma on days 1, 2, 3, 5, and 14 from the onset of fever in 35 patients.

Results

Thirteen patients (37.1%) developed sepsis. In mixed models, IL-6, IL-8, IL-10, and G-CSF showed higher estimated means in septic patients (P < 0.005), and IL-12/23p40 and IL-17 in nonseptic patients (P < 0.05). On day 1, IL-6, IL-8, and IL-10 appeared upregulated in patients who received filgrastim. Only IL-6, IL-8, IL-10, and procalcitonin were useful as discriminators of sepsis. Associating the markers with each other or to a risk assessment model improved performance.

Conclusions

Cytokines kinetics showed proinflammatory and anti-inflammatory responses similar to what is described in nonneutropenic patients. IL-8, IL-6, IL-10, and procalcitonin are useful as early biomarkers of sepsis. Filgrastim upregulates expression of these markers, and we observed deficiency in the IL-23-IL-17 axis accompanying sepsis.

Prospective cohort study of procalcitonin levels in children with cancer presenting with febrile neutropenia

Background

Febrile neutropenia (FNP) causes significant morbidity and mortality in children undergoing treatment for cancer. The development of clinical decision rules to help stratify risks in paediatric FNP patients and the use of inflammatory biomarkers to identify high risk patients is an area of recent research. This study aimed to assess if procalcitonin (PCT) levels could be used to help diagnose or exclude severe infection in children with cancer who present with febrile neutropenia, both as a single measurement and in addition to previously developed clinical decision rules.

Methods

This prospective cohort study of a diagnostic test included patients between birth and 18 years old admitted with febrile neutropenia to the Paediatric Oncology and Haematology Ward in Leeds between 1^st October 2012 and 30^th September 2013. Each admission with FNP was treated as a separate episode. Blood was taken for a procalcitonin level at admission with routine investigations. ‘R’ was used for statistical analysis. Likelihood ratios were calculated and multivariable logistic regression.

Results

Forty-eight episodes from 27 patients were included. PCT >2 ng/dL was strongly associated with increased risk of severe infection (likelihood ratio of 26 [95% CI 3.5, 190]). The data suggests that the clinical decision rules are largely ineffective at risk stratification, frequently over-stating the risk of individual episodes. High procalcitonin levels on admission are correlated with a greatly increased risk of severe infection.

Conclusions

This study does not show a definitive benefit in using PCT in FNP though it supports further research on its use. The benefit of novel biomarkers has not been proven and before introducing new tests for patients it is important their benefit above existing features is proven, particularly due to the increasing importance of health economics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-016-0766-8) contains supplementary material, which is available to authorized users.

Sepsis and AKI in Clinical Emergency Room Patients: The Role of Urinary NGAL

BACKGROUND

Few studies have investigated the predictive properties of urinary (u) NGAL as an AKI marker in septic population.

OBJECTIVES

This study evaluated the efficacy of uNGAL as predictor of AKI and death in septic patients admitted to the clinical emergency room (ER).

METHODOLOGY

We prospectively studied patients with sepsis admitted to the ER. Urine was analyzed for NGAL within the first 24 hours after admission (classified as NGAL1), between 24 and 48 h (NGAL2), and at moment of AKI diagnosis (NGAL3).

RESULTS

Among 168 septic patients admitted to ER, 72% developed AKI. The uNGAL and its relationship with creatinine (Cr) were high in septic patients but statistically higher in those with sepsis and AKI. The uNGAL1 and uNGAL2, as well as uNGAL1/uCr1 and uNGAL2/uCr2, were good predictors for AKI (AUC-ROC 0.73, 0.70, 0.77, and 0.84, resp.). The uNGAL1 and uNGAL1/uCr1 were poor predictors for death (AUC-ROC 0.66 and 0.68, resp.), whereas uNGAL2 and uNGAL2/uCr2 were better predictors (AUC-ROC 0.70 and 0.81, resp.).

CONCLUSION

The uNGAL is highly sensitive but nonspecific predictor of AKI and death in septic patients admitted into ER.

Conventional, molecular methods and biomarkers molecules in detection of septicemia

Sepsis is a leading cause of morbidity and mortality in hospitalized patients worldwide and based on studies, 30–40% of all cases of severe sepsis and septic shock results from the blood stream infections (BSIs). Identifying of the disease, performing laboratory tests, and consequently treatment are factors that required for optimum management of BSIs. In addition, applying precise and immediate identification of the etiologic agent is a prerequisite for specific antibiotic therapy of pathogen and thereby decreasing mortality rates. The diagnosis of sepsis is difficult because clinical signs of sepsis often overlap with other noninfectious cases of systemic inflammation. BSIs are usually diagnosed by performing a series of techniques such as blood cultures, polymerase chain reaction-based methods, and biomarkers of sepsis. Extremely time-consuming even to take up to several days is a major limitation of conventional methods. In addition, yielding false-negative results due to fastidious and slow-growing microorganisms and also in case of antibiotic pretreated samples are other limitations. In comparison, molecular methods are capable of examining a blood sample obtained from suspicious patient with BSI and gave the all required information to prescribing antimicrobial therapy for detected bacterial or fungal infections immediately. Because of an emergency of sepsis, new methods are being developed. In this review, we discussed about the most important sepsis diagnostic methods and numbered the advantage and disadvantage of the methods in detail.

Selected inflammatory markers in the diagnosis and monitoring of infections in children treated for hematological malignancies

Infections in children treated for hematological malignancies pose a direct threat to life and are one of the most common causes of treatment failure in this group of patients. Unequivocal diagnosis at the early stages of infection together with an appropriate and timely treatment may be often difficult due to poor manifestation and nonspecific clinical symptoms of the infection progress. Inflammatory markers make a useful diagnostic tool for this purpose. They significantly help to diagnose, monitor, stratify and predict the outcome in severe infections. This article describes selected biomarkers, both those commonly used in clinical practice, such as erythrocyte sedimentation rate, C-reactive protein, procalcitonin as well as less common like IL-6, IL-8 and moreover one promising novel marker – pentraxin 3. The authors emphasize their diagnostic value, clinical usefulness and significance in the treatment efficacy monitoring.

Efficacy of measuring procalcitonin levels in determination of prognosis and early diagnosis of bacterial resistance in sepsis

Background:

Rapid and proper diagnosis of sepsis is one of the daily challenges of emergency department (ED) and intensive care units. The general aim of the present study was to determine the efficacy of measuring procalcitonin levels in the early diagnosis of bacterial resistance to antibiotics administered empirically in patients with sepsis.

Materials and Methods:

The present cross-sectional study consisted of patients with clinical evidence of sepsis or systemic inflammatory response syndrome (SIRS), referring to the ED of a third-level hospital in Tehran, Iran in 2012. After collection of basic and clinical data of patients, venous blood samples were taken for routine laboratory tests and determination of procalcitonin serum levels at baseline and 6 and 24 hours after administration of the first dose of an empirical antibiotic. The subjects were divided into two groups of discharged and expired and then comparisons were made using t-test, Chi-squared test and Fisher's test. Specificity and sensitivity of procalcitonin were evaluated along with ROC curve.

Results:

In the present study, 170 patients with sepsis were included. Evaluation of serum levels of procalcitonin 24 hours after administration of antibiotics exhibited the best sensitivity and specificity for each patient's response to antibiotics. Use of the cutoff point of 6.5 mg/mL for procalcitonin can predict the disease outcome with sensitivity and specificity of 67% and 80%, respectively.

Conclusion:

It is suggested that procalcitonin be used for the diagnosis of sepsis or SIRS resulting from an infectious disease, for follow-up of treatment and for evaluation of response to treatment.

The chemokine ligand CXCL16 is an indicator of bacterial infection in necrotizing pancreatitis

OBJECTIVES

Current guidelines tell us that intervention in severe necrotizing pancreatitis ought to be performed as late as possible. However, when pancreatic necrosis becomes infected, the necrotic tissue needs to be removed. Unfortunately, bacterial infection can only be proven by invasive methods.

METHODS

Necrotizing pancreatitis with sterile or infected necrosis was induced in mice. Mice serum samples were examined by antibody-based protein array. After identifying candidate proteins that showed strong regulation, the serum concentration of these proteins was examined by sandwich ELISA. Then, human serum samples were collected from patients with mild pancreatitis, severe pancreatitis with and without pancreatic necrosis and patients with microbiologically proven infection of pancreatic necrosis. These serum samples were then analyzed by sandwich ELISA.

RESULTS

In mice 6 proteins were strongly up-regulated and were further investigated by ELISAs. Of these proteins, CXCL16 and TRANCE (RANKL) concentrations were analyzed in human serum samples. CXCL16 and TRANCE were increased in patients with pancreatic necrosis and abdominal infection. Receiver operated characteristics showed that CXCL16 was superior in predicting infected pancreatic necrosis when compared to C-reactive protein and TRANCE.

CONCLUSIONS

Serum CXCL16 is increased in severe pancreatitis with infected pancreatic necrosis and identifies patients who benefit from surgical necrosectomy.

Is salivary pH a marker of depression among older spousal caregivers for cancer patients?

The pH in saliva, which decreases due to the activation of the sympathetic nervous system, may serve as a biomarker of psychological distress in caregivers but has rarely been studied in this context. The aims are to examine the levels of salivary pH as a possible biomarker of depression among caregivers and whether depression mediates the association between caregiving status (cancer caregivers vs. non-cancer caregivers) and pH levels. Cross-sectional data were collected from 68 consecutive-sampled spouses of cancer patients, and 42 age-matched individuals. Lower levels of pH saliva were found among caregivers of cancer patients than in the comparison group. Being a caregiver, poor subjective health, higher depression, and lower mastery predicted lower pH levels. In addition, depression mediated the associations of mastery with pH levels. The study provides preliminary evidence that salivary pH may serve as an easily tested indicator of the stress of caregiving and its related depression.

Management of febrile neutropenia in the era of bacterial resistance

Managing cancer patients with fever and neutropenia must be considered as a medical emergency since any delay in initiating appropriate empirical antibacterial therapy may result in high rates of mortality and morbidity. Emerging antibacterial resistance in bacterial pathogens infecting febrile neutropenic patients complicates management, and choosing the type of empirical antimicrobial therapy has become a challenge. To further complicate the decision process, not all neutropenic patients are in same category of susceptibility to develop severe infection. While low-risk patients may be treated with oral antibiotics in the outpatient setting, high-risk patients usually need to be admitted to hospital and receive parenteral broad-spectrum antibiotics until the neutrophil levels recover. These strategies have recently been addressed in two international guidelines from the Infectious Diseases Society of America (IDSA) and the European Conference on Infections in Leukaemia (ECIL). This review gives a brief overview of current antimicrobial resistance problems and their effects in febrile neutropenic cancer patients by summarizing the suggestions from the IDSA and ECIL guidelines.

Biomarkers of sepsis

Sepsis is an unusual systemic reaction to what is sometimes an otherwise ordinary infection, and it probably represents a pattern of response by the immune system to injury. A hyper-inflammatory response is followed by an immunosuppressive phase during which multiple organ dysfunction is present and the patient is susceptible to nosocomial infection. Biomarkers to diagnose sepsis may allow early intervention which, although primarily supportive, can reduce the risk of death. Although lactate is currently the most commonly used biomarker to identify sepsis, other biomarkers may help to enhance lactate’s effectiveness; these include markers of the hyper-inflammatory phase of sepsis, such as pro-inflammatory cytokines and chemokines; proteins such as C-reactive protein and procalcitonin which are synthesized in response to infection and inflammation; and markers of neutrophil and monocyte activation. Recently, markers of the immunosuppressive phase of sepsis, such as anti-inflammatory cytokines, and alterations of the cell surface markers of monocytes and lymphocytes have been examined. Combinations of pro- and anti-inflammatory biomarkers in a multi-marker panel may help identify patients who are developing severe sepsis before organ dysfunction has advanced too far. Combined with innovative approaches to treatment that target the immunosuppressive phase, these biomarkers may help to reduce the mortality rate associated with severe sepsis which, despite advances in supportive measures, remains high.

Significance of interleukin-6 (IL-6) and C-reactive protein (CRP) in children and young adults with febrile neutropenia during chemotherapy for cancer: a prospective study

OBJECTIVES

We evaluated the usefulness of interleukin-6 (IL-6) and C-reactive protein (CRP) at the onset of febrile neutropenia and 72 hours later, in identifying risk groups and assessing response to antibiotic therapy.

METHODS

All episodes of febrile neutropenia were divided in 3 study groups-microbiologically documented infection (MDI), clinically documented infection (CDI), and fever of unknown origin (FUO). Three outcome groups were defined as those responding to first-line antibiotics (R1), those responding to second-line antibiotics (R2), and those requiring antifungal therapy (RAF). Median values of IL-6 and CRP were compared between the groups.

RESULTS

There were 57 episodes of febrile neutropenia among 26 patients younger than 25 years during 1 year of study period. On day 1, median IL-6 level was significantly lower in FUO group compared with CDI+MDI groups combined (P < 0.001). Rise in CRP on day 3 was highly significant to differentiate MDI group from other 2 groups (P < 0.001). The CRP also increased significantly on day 3 in RAF (P < 0.001) and R2 (P = 0.002) groups than in R1 group.

CONCLUSIONS

Low level of IL-6 may help differentiate patients with FUO from those with documented infections. A rising CRP is indicative of serious infection.

IL-10 combined with procalcitonin improves early prediction of complications of febrile neutropenia in hematological patients

Early diagnosis of complicated course in febrile neutropenia is cumbersome due to the non-specificity of clinical and laboratory signs of severe infection. This prospective study included 100 adult hematological patients with febrile neutropenia after intensive chemotherapy at the onset of fever (d0) and for 3 days (d1-d3) thereafter. The study aim was to find early predictors for complicated course of febrile neutropenia, defined as bacteremia or septic shock. Interleukin 6 (IL-6), interleukin 10 (IL-10), procalcitonin (PCT) and C-reactive protein (CRP) all predicted complicated course of febrile neutropenia on d0, but only PCT was predictive throughout the study period. For IL-10 on d0-1 with cut-off 37 ng/L, sensitivity was 0.71, specificity 0.82, positive predictive value 0.52 and negative predictive value 0.92. For PCT on d0-1 with cut-off 0.13 μg/L, the respective measures were 0.95, 0.53, 0.36, and 0.98. For the combination of IL-10 and PCT on d0-1 with the same cut-offs, specificity improved to 0.85 and positive predictive value to 0.56. In conclusion, the present study confirms the high negative predictive value of PCT and provides new evidence for IL-10 as an early predictor for complicated course of febrile neutropenia in hematological patients. Combining IL-10 with PCT improves the early prediction for complicated course of febrile neutropenia.

Biomarkers for risk stratification of febrile neutropenia among children with malignancy: a pilot study

BACKGROUND

Patients receiving myelosuppressive chemotherapy remain at increased risk for developing febrile neutropenia (FN). For this heterogeneous population, a biomarker based risk stratification of FN patients may be a useful clinical tool. We hypothesized that serum biomarkers during initial presentation of an FN event could be predictive of subsequent clinical outcome.

PROCEDURE

Eighty-nine FN events from 36 non-consecutive subjects were analyzed. "High-risk" FN criteria included prolonged hospitalization (≥ 7 days), admission to pediatric intensive care unit (PICU) or a microbiology confirmed bacteremia. Patients with "low risk" FN had none of the above. Biomarkers measured during the first 2 days of FN hospitalization were analyzed and correlated with respective clinical outcome.

RESULTS

Of the 89 FN events, 44 (49%) fulfilled pre-defined high-risk criteria and 45 (51%) were low-risk. Procalcitonin level (>0.11 ng/ml) was found to be associated with the high-risk FN outcome with sensitivity of 97%. With an increase in log scale by 1, the odds of being high-risk FN increased twofold. Hs-CRP >100 mg/L had sensitivity of 88% in predicting high-risk FN. The odds of a high-risk FN event increased by approximately 1.8-fold with an increase in the log scale of hs-CRP by 1 (10-fold). In univariate analysis, IL-6, IL-8, and IL-10 were statistically significant and associated with high-risk FN. However, no statistically significant difference was found for IL-1α, sIL-2Ra, IL-3, or TNF-α.

CONCLUSIONS

Biomarkers with appropriate critical threshold values may be a useful clinical tool for appropriate risk stratification of children with FN.

Predictive value of interleukin-5 and monocyte chemotactic protein-1 for bacteremia in children with febrile neutropenia

A variety of clinical and laboratory parameters have been used to predict bacteremia. We hypothesize that the generation of a cytokine profile could be used to identify patients at higher risk of bacteremia at the time of presentation with febrile neutropenia. We prospectively evaluated children with cancer who presented with an episode of febrile neutropenia. A multiplexed flow cytometric assay was performed which measured 15 cytokines and chemokines obtained before the initiation of antibiotics. Fifty-eight episodes of chemotherapy-induced febrile neutropenia were included in this study during which 4 patients (7%) had bacteremia. An interleukin-5 level of >8 pg/dL had a sensitivity of 67% and a specificity of 96% to predict bacteremia. An monocyte chemotactic protein-1 level >1650 pg/dL had a sensitivity of 80% and a specificity of 82% to predict bacteremia. Erythrocyte sedimentation rate, C-reactive protein, protein C, and other cytokines/chemokines were not predictive of bacteremia. Elevations of interleukin-5 and monocyte chemotactic protein-1 are predictive of bacteremia in children with cancer who have febrile neutropenia. Prospective studies should be undertaken to determine whether these parameters retain predictive value in a larger series of patients and can select children for outpatient management or early discharge.

Baseline evaluation of serum markers of inflammation and their utility in clinical practice in paediatric liver transplant recipients

BACKGROUND

Several biomarkers of penetrating infections vs. rejection in liver transplant (LT) have been suggested; however, baseline values in paediatric LT recipients have not been studied.

AIM

We evaluated the baseline concentration of procalcitonin (PCT), C-reactive protein (CRP) and interleukin-6 (IL-6) in a post-LT paediatric group.

METHODS

We measured serum PCT, CRP and IL-6 in 58 consecutive paediatric LT recipients. Specimens were collected for group 1 (n=22) at day 1, group 2 (n=12) at day 7 post-LT and group 3 (n=24) at onset of febrile episode. Day 7 samples were obtained from patients who had no graft dysfunction or signs/symptoms of sepsis.

RESULTS

Median values for PCT were: group 1 was 5.16 μg/L (95% CI, 2.18-21.13); group 2: 0.170 μg/L (95% CI, 0.15-0.36) and, group 3: 1.93 μg/L (95% CI, 1.36-2.66) for bacterial and fungal infection, 0.19 μg/L (95% CI, 0.10-0.48) for rejection, and 0.31 μg/L (95% CI, 0.15-0.44) for viral infection. The area under the ROC (AUROC) for PCT, CRP and IL-6 in bacterial infection vs. rejection was 1.0 (P<0.0001), 0.842 (95% CI 0.686-0.998; P<0.0001) and 0.739 (95% CI 0.559-0.919; P 0.0046), respectively.

CONCLUSION

PCT levels were significantly higher in bacterial and fungal infection in comparison to other inflammatory markers. PCT proved to be the most specific parameter in differentiating bacterial infection from viral infection and allograft rejection.

Evaluation of circulating soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) to predict risk profile, response to antimicrobial therapy, and development of complications in patients with chemotherapy-associated febrile neutropenia: a pilot study

The soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) is a useful marker of infection in patients with sepsis, but has not been adequately evaluated in patients with chemotherapy-associated febrile neutropenia (FN). The value of sTREM-1 in this setting has been tested in a retrospective, pilot study using stored serum from 48 cancer patients with documented FN. On presentation, patients were categorized according to the Talcott risk-index clinical score. Circulating soluble sTREM-1 was measured using an ELISA procedure, while procalcitonin (PCT) or interleukins 6 (IL-6) and 8 (IL-8), included for comparison, were measured using an immunoluminescence-based assay and Bio-Plex® suspension bead array system, respectively. Circulating concentrations of both sTREM-1 and PCT were significantly (P < 0.05) elevated in patients at high risk for complications or death, as predicted by the Talcott score and were significantly lower in patients who responded to empiric antimicrobial agents. Neither IL-6 nor IL-8 accurately predicted serious complications in patients with FN. These observations, albeit from a pilot study, demonstrate that sTREM-1 is indeed elevated in high-risk patients with FN and is potentially useful to predict their clinical course, either together with, or as an alternative to PCT.

Cytokine levels as potential biomarkers for predicting the development of posttraumatic stress symptoms in casualties of accidents

BACKGROUND

Traumatic injuries are usually associated with increased secretion of pro-inflammatory cytokines, and are sometimes followed by the development of acute stress symptoms (ASS) and posttraumatic stress symptoms (PTSS).

AIMS

To measure serum pro- and anti-inflammatory cytokines in accident casualties and to associate it with ASS at hospitalization, and with PTSS 1 month later.

METHODS

Participants were 48 patients, aged 20-60, hospitalized following various orthopedic injuries including bone fractures, and 13 healthy volunteers matched for gender. At hospitalization (Time 1), 30 ml heparinized venous blood were drawn and cytokines levels in serum were assessed; participants filled out the Acute Stress Disorder Inventory (ASDI), COPE, and injury-related questionnaires. One month later (Time 2), 26 participants filled out the Posttraumatic Disorder Symptom Scale (PDS).

RESULTS

High serum levels of IL-6, IL-8, and TGF-beta and low levels of serum IL-4 and IL-10 were found in injured patients as compared with controls, When controlling for age and severity of injury in the regression analysis, higher levels of IL-6 and IL-8 and lower TGF-beta were predicted by higher ASS and higher use of and emotion-focused coping. Higher PTSS scores at Time 2 were predicted by higher levels of IL-8, lower levels of TGF-beta, and higher ASS measured at Time 1.

CONCLUSIONS

High levels of the pro-inflammatory cytokine IL-6 and IL-8 and lower levels of the regulatory cytokine TGF-beta should be further assessed as a possible risk factor or a bio-marker of PTSS in accident casualties.

The diagnostic value of interleukin-6 and interleukin-8 for early prediction of bacteremia and sepsis in children with febrile neutropenia and cancer

BACKGROUND AND AIM

Early diagnosis of sepsis in children with febrile neutropenia and cancer still remains a challenge for modern medicine because of lack of specific laboratory markers and clinical signs especially at the beginning of the infection. The objective of this study was to evaluate the ability of interleukin-6 and interleukin-8 to predict bacteremia and sepsis during the first 2 days in oncohematologic patients with febrile neutropenia.

PATIENTS AND METHODS

A total of 61 febrile neutropenic episodes in 37 children were studied. Serum samples were collected on day 1 and day 2 from the onset of fever and analyzed using an automated random access analyzer.

RESULTS

Neutropenic children with febrile episodes were classified into the following 2 groups: (1) fever of unknown origin group--patients with a negative blood culture--and (2) bacteremia/sepsis group--patients with a positive blood culture or clinical sepsis. High negative predictive values were found on day 1 for interleukin-6 and interleukin-8 (89% and 82%, respectively) for exclusion of bacteremia/sepsis.

CONCLUSIONS

These interleukins could be used as a screening tool for the rejection of sepsis or bacteremia on the first day of fever in neutropenic children with cancer.

Sapovirus as a gastrointestinal pathogen in febrile pediatric patients with cancer

Human caliciviruses are the second most common cause of viral gastroenteritis after rotavirus in children. Unlike norovirus, sapovirus infection is less well characterized and defined in the clinical setting of gastrointestinal disease, and there are no reports of sapovirus infections in pediatric oncology patients receiving chemotherapy treatment. Stool samples from all pediatric oncology patients presenting with fever and diarrhea at one pediatric oncology unit were tested prospectively for sapovirus by real-time reverse transcription-PCR sapovirus genogrouping was performed by nested PCR. Sapovirus was detected in 2 of 100 stool specimens prospectively sampled from 58 symptomatic pediatric oncology inpatients between December 2008 and September 2009. Both patients received low-dose chemotherapy for their underlying conditions at the time of infection with sapovirus. Genogrouping of the viruses showed the presence of a GI.1 strain and GII.3 strain, unlike the most common GI.2 strain responsible for outbreaks in different European countries. The contribution of sapovirus infection to the morbidity of pediatric cancer patients and its potential for nosocomial spread is discussed. Sapovirus, an often unrecognized pathogen, should be considered along with other viruses in pediatric cancer patients suffering from gastrointestinal disease.

Miniaturized protein microarray with internal calibration as point-of-care device for diagnosis of neonatal sepsis

Neonatal sepsis is still a leading cause of death among newborns. Therefore a protein-microarray for point-of-care testing that simultaneously quantifies the sepsis associated serum proteins IL-6, IL-8, IL-10, TNF alpha, S-100, PCT, E-Selectin, CRP and Neopterin has been developed. The chip works with only a 4 μL patient serum sample and hence minimizes excessive blood withdrawal from newborns. The 4 μL patient samples are diluted with 36 μL assay buffer and distributed to four slides for repetitive measurements. Streptavidin coated magnetic particles that act as distinct stirring detection components are added, not only to stir the sample, but also to detect antibody antigen binding events. We demonstrate that the test is complete within 2.5 h using a single step assay. S-100 conjugated to BSA is spotted in increasing concentrations to create an internal calibration. The presented low volume protein-chip fulfills the requirements of point-of-care testing for accurate and repeatable (CV < 14%) quantification of serum proteins for the diagnosis of neonatal sepsis.

Systematic review and meta-analysis of the value of initial biomarkers in predicting adverse outcome in febrile neutropenic episodes in children and young people with cancer

BACKGROUND

Febrile neutropenia is a frequently occurring and occasionally life-threatening complication of treatment for childhood cancer. Many biomarkers have been proposed as predictors of adverse events. We aimed to undertake a systematic review and meta-analysis to summarize evidence on the discriminatory ability of initial serum biomarkers of febrile neutropenic episodes in children and young people.

METHODS

This review was conducted in accordance with the Center for Reviews and Dissemination Methods, using three random effects models to undertake meta-analysis. It was registered with the HTA Registry of systematic reviews, CRD32009100485.

RESULTS

We found that 25 studies exploring 14 different biomarkers were assessed in 3,585 episodes of febrile neutropenia. C-reactive protein (CRP), pro-calcitonin (PCT), and interleukin-6 (IL6) were subject to quantitative meta-analysis, and revealed huge inconsistencies and heterogeneity in the studies included in this review. Only CRP has been evaluated in assessing its value over the predictive value of simple clinical decision rules.

CONCLUSIONS

The limited data available describing the predictive value of biomarkers in the setting of pediatric febrile neutropenia mean firm conclusions cannot yet be reached, although the use of IL6, IL8 and procalcitonin warrant further study.

GEF-H1-RhoA signaling pathway mediates LPS-induced NF-κB transactivation and IL-8 synthesis in endothelial cells

Secretion of proinflammatory cytokines by LPS activated endothelial cells contributes substantially to the pathogenesis of sepsis. However, the mechanism involved in this process is not well understood. In the present study, we determined the roles of GEF-H1 (guanine-nucleotide exchange factor-H1)-RhoA signaling in LPS-induced interleukin-8 (IL-8, CXCL8) production in endothelial cells. First, we observed that GEF-H1 expression was upregulated in a dose- and time-dependent manner as consistent with TLR4 (Toll-like receptor 4) expression after LPS stimulation. Afterwards, Clostridium difficile toxin B-10463 (TcdB-10463), an inhibitor of Rho activities, reduced LPS-induced NF-κB phosphorylation. Inhibition of GEF-H1 and RhoA expression reduced LPS-induced NF-κB and p38 phosphorylation. TLR4 knockout blocked LPS-induced activity of RhoA, however, MyD88 knockout did not impair the LPS-induced activity of RhoA. Nevertheless, TLR4 and MyD88 knockout both significantly inhibited transactivation of NF-κB. GEF-H1-RhoA and MyD88 both induced significant changes in NF-κB transactivation and IL-8 synthesis. Co-inhibition of GEF-H1-RhoA and p38 expression produced similar inhibitory effects on LPS-induced NF-κB transactivation and IL-8 synthesis as inhibition of p38 expression alone, thus confirming that activation of p38 was essential for the GEF-H1-RhoA signaling pathway to induce NF-κB transactivation and IL-8 synthesis. Taken together, these results demonstrate that LPS-induced NF-κB activation and IL-8 synthesis in endothelial cells are regulated by the MyD88 pathway and GEF-H1-RhoA pathway.

Th1/Th2 cytokine profiles in G+/G- bacteremia in pediatric hematology/oncology patients

BACKGROUND

Early diagnosis of infection and appropriate choice of antibiotics are essential not only to improve the prognosis of the patients but also to prevent from the abuse of the antibiotics in hematology/oncology children at the time of neutropenia after intensive chemotherapy.

PROCEDURE

We evaluated the quantification of Th1/Th2 cytokines with flow cytometry bead assay (CBA) in 145 hospitalized febrile hematology/oncology children with positive blood culture to seek for a rapid diagnostic method to determine the type of infection.

RESULTS

IL-4, IL-6, IL-10, TNF-α, and IFN-γ levels from both G- and G+ bacteremia groups were significantly higher than those of controls (P < 0.001). The median levels of IL-6, IL-10, TNF-α of Group G- were 525.4, 96.0, and 6.9 pg/ml, respectively, significantly higher than those of Group G+ (150.0, 22.6, and 4.5 pg/ml, respectively, P < 0.001). According to the different degrees of increased IL-6 and IL-10 levels, we named the G- bacterial infection related cytokine profile G- BIRCP and the G+ BIRCP. The specificity and sensitivity of BIRCP prediction for G- and G+ bacteria cultures were 60.2% and 75.4%, 66.8% and 70.1%, respectively. Similar therapeutic efficacy was achieved between BIRCP-based and broad-spectrum antibiotics groups (86.1% vs. 89.3%, P > 0.05), which was significantly increased as compared with that (65.5%, P < 0.05) of empirical group.

CONCLUSIONS

These results showed the promising use of the IL-6/IL-10/TNF-α determination with CBA technology for the early and rapid diagnosis, evaluation of G+/G- bacteremia in pediatric hematology/oncology patients.

Increased interleukin-10 levels correlate with bacteremia and sepsis in febrile neutropenia pediatric oncology patients

BACKGROUND

Early diagnosis of bacteremia and sepsis in pediatric oncology patients with febrile neutropenia still remains unresolved task due to lack of sensitive and specific laboratory markers particularly at the beginning of the infectious process. The objective of our study was to assess the potentiality of interleukin-10 (IL-10) to predict or exclude bacteremia or sepsis at the beginning of febrile episode in childhood oncology patients.

METHODS

A total of 36 febrile neutropenic episodes in 24 children were studied. Serum samples were collected after confirmation of febrile neutropenia and analyzed using automated random access analyzer.

RESULTS

The sensitivity of IL-10 was 73% and specificity - 92% (cut-off=18pg/ml, area under the curve - 0.87, 95% CI for sensitivity 39-94%, 95% CI for specificity 74-99%) with negative predictive value (NPV) - 83%.

CONCLUSIONS

IL-10 evaluation might be used as an additional diagnostic tool for clinicians in excluding bacteremia or clinical sepsis in oncology patients with febrile neutropenia because of high NPV and specificity.

Comparative levels of macrophage migration inhibitory factor, procalcitonin, osteoprotegerin, interleukin-8, hs-C reactive protein, D-dimer in febrile neutropenia, newly diagnosed cancer patients, and infectious fever

BACKGROUND

The purpose of this study is to determine the levels of procalcitonin (PCT), IL-8 (interleukin-8), MIF (macrophage migration inhibitory factor), osteoprotegerin (OPG), hs-CRP and D-dimer during fever above 38.3°C due to various causes.

MATERIAL AND METHODS

Blood samples taken from a total of consecutive 65 hospitalized patients during fever were prospectively tested for hsCRP, PCT, IL-8, OPG, MIF and D-dimer. Of these patients, there were 26 patients presenting with chemotherapy-induced neutropenia who had no infectious agents found; 23 patients, who had a malignancy with a febrile episode which was neither a microbiologically documented infection nor a chemotherapy-induced neutropenia, and 16 patients who did not have a malignancy and were considered to have a clinically and microbiologically documented infection.

RESULTS

IL-8 and D-dimer levels were higher in patients with febrile neutropenia than in the other two groups. Although MIF and OPG were higher in patients with newly diagnosed cancers, there were no differences among the three groups regarding PCT and hs-CRP values.

CONCLUSION

High serum IL-8 and D-dimer levels can be useful markers to identify hospitalized chemotherapy-induced neutropenia patients. MIF and OPG were found to be higher in patients with newly diagnosed cancer.

Discriminative value of inflammatory biomarkers for suspected sepsis

BACKGROUND

Circulating biomarkers can facilitate sepsis diagnosis, enabling early management and improved outcomes. Procalcitonin (PCT) has been suggested to have superior diagnostic utility compared to other biomarkers.

STUDY OBJECTIVES

To define the discriminative value of PCT, interleukin-6 (IL-6), and C-reactive protein (CRP) for suspected sepsis.

METHODS

PCT, CRP, and IL-6 were correlated with infection likelihood, sepsis severity, and septicemia. Multivariable models were constructed for length-of-stay and discharge to a higher level of care.

RESULTS

Of 336 enrolled subjects, 60% had definite infection, 13% possible infection, and 27% no infection. Of those with infection, 202 presented with sepsis, 28 with severe sepsis, and 17 with septic shock. Overall, 21% of subjects were septicemic. PCT, IL6, and CRP levels were higher in septicemia (median PCT 2.3 vs. 0.2 ng/mL; IL-6 178 vs. 72 pg/mL; CRP 106 vs. 62 mg/dL; p < 0.001). Biomarker concentrations increased with likelihood of infection and sepsis severity. Using receiver operating characteristic analysis, PCT best predicted septicemia (0.78 vs. IL-6 0.70 and CRP 0.67), but CRP better identified clinical infection (0.75 vs. PCT 0.71 and IL-6 0.69). A PCT cutoff of 0.5 ng/mL had 72.6% sensitivity and 69.5% specificity for bacteremia, as well as 40.7% sensitivity and 87.2% specificity for diagnosing infection. A combined clinical-biomarker model revealed that CRP was marginally associated with length of stay (p = 0.015), but no biomarker independently predicted discharge to a higher level of care.

CONCLUSIONS

In adult emergency department patients with suspected sepsis, PCT, IL-6, and CRP highly correlate with several infection parameters, but are inadequately discriminating to be used independently as diagnostic tools.

Procalcitonin for diagnosis of infection and guide to antibiotic decisions: past, present and future

There are a number of limitations to using conventional diagnostic markers for patients with clinical suspicion of infection. As a consequence, unnecessary and prolonged exposure to antimicrobial agents adversely affect patient outcomes, while inappropriate antibiotic therapy increases antibiotic resistance. A growing body of evidence supports the use of procalcitonin (PCT) to improve diagnosis of bacterial infections and to guide antibiotic therapy. For patients with upper and lower respiratory tract infection, post-operative infections and for severe sepsis patients in the intensive care unit, randomized-controlled trials have shown a benefit of using PCT algorithms to guide decisions about initiation and/or discontinuation of antibiotic therapy. For some other types of infections, observational studies have shown promising first results, but further intervention studies are needed before use of PCT in clinical routine can be recommended. The aim of this review is to summarize the current evidence for PCT in different infections and clinical settings, and discuss the reliability of this marker when used with validated diagnostic algorithms.

Predicting bacteremia in children with cancer and fever in chemotherapy-induced neutropenia: results of the prospective multicenter SPOG 2003 FN study

STUDY AIM

To develop a score predicting the risk of bacteremia in cancer patients with fever and neutropenia (FN), and to evaluate its performance.

METHODS

Pediatric patients with cancer presenting with FN induced by nonmyeloablative chemotherapy were observed in a prospective multicenter study. A score predicting the risk of bacteremia was developed from a multivariate mixed logistic regression model. Its cross-validated predictive performance was compared with that of published risk prediction rules.

RESULTS

Bacteremia was reported in 67 (16%) of 423 FN episodes. In 34 episodes (8%), bacteremia became known only after reassessment after 8 to 24 hours of inpatient management. Predicting bacteremia at reassessment was better than prediction at presentation with FN. A differential leukocyte count did not increase the predictive performance. The reassessment score predicting future bacteremia in 390 episodes without known bacteremia used the following 4 variables: hemoglobin ≥ 90 g/L at presentation (weight 3), platelet count <50 G/L (3), shaking chills (5), and other need for inpatient treatment or observation according to the treating physician (3). Applying a threshold ≥ 3, the score--simplified into a low-risk checklist--predicted bacteremia with 100% sensitivity, with 54 episodes (13%) classified as low-risk, and a specificity of 15%.

CONCLUSIONS

This reassessment score, simplified into a low-risk checklist of 4 routinely accessible characteristics, identifies pediatric patients with FN at risk for bacteremia. It has the potential to contribute to the reduction of use of antimicrobials in, and to shorten the length of hospital stays of pediatric patients with cancer and FN.

Monitoring procalcitonin in febrile neutropenia: what is its utility for initial diagnosis of infection and reassessment in persistent fever?

Background

Management of febrile neutropenic episodes (FE) is challenged by lacking microbiological and clinical documentation of infection. We aimed at evaluating the utility of monitoring blood procalcitonin (PCT) in FE for initial diagnosis of infection and reassessment in persistent fever.

Methods

PCT kinetics was prospectively monitored in 194 consecutive FE (1771 blood samples): 65 microbiologically documented infections (MDI, 33.5%; 49 due to non-coagulase-negative staphylococci, non-CNS), 68 clinically documented infections (CDI, 35%; 39 deep-seated), and 61 fever of unexplained origin (FUO, 31.5%).

Results

At fever onset median PCT was 190 pg/mL (range 30–26'800), without significant difference among MDI, CDI and FUO. PCT peak occurred on day 2 after onset of fever: non-CNS-MDI/deep-seated-CDI (656, 80–86350) vs. FUO (205, 33–771; p<0.001). PCT >500 pg/mL distinguished non-CNS-MDI/deep-seated-CDI from FUO with 56% sensitivity and 90% specificity. PCT was >500 pg/ml in only 10% of FUO (688, 570–771). A PCT peak >500 pg/mL (1196, 524–11950) occurred beyond 3 days of persistent fever in 17/21 (81%) invasive fungal diseases (IFD). This late PCT peak identified IFD with 81% sensitivity and 57% specificity and preceded diagnosis according to EORTC-MSG criteria in 41% of cases. In IFD responding to therapy, median days to PCT <500 pg/mL and defervescence were 5 (1–23) vs. 10 (3–22; p = 0.026), respectively.

Conclusion

While procalcitonin is not useful for diagnosis of infection at onset of neutropenic fever, it may help to distinguish a minority of potentially severe infections among FUOs on day 2 after onset of fever. In persistent fever monitoring procalcitonin contributes to early diagnosis and follow-up of invasive mycoses.

Interleukin-6 in surgery, trauma, and critical care part II: clinical implications

A variety of cytokines play a role in the inflammatory response. Interleukin-6 (IL-6)-type cytokines are released in response to tissue injury or an inflammatory stimulus, and act locally and systemically to generate a variety of physiologic responses. Interleukin-6 concentrations are elevated after surgery, trauma, and critical illness. The magnitude of IL-6 elevation correlates with the extent of tissue trauma/injury severity. Furthermore, there is an association between IL-6 elevation and adverse outcome. Interleukin-6 levels can also be used to stratify patients for therapeutic intervention.

Established and novel biomarkers of sepsis

The increased incidence of sepsis, a systemic response to infection that occurs in some patients, has stimulated interest in identifying infected patients who are at risk and intervening early. When this condition progresses to severe sepsis (characterized by organ dysfunction), mortality is high. Hospitals that have implemented recommendations of the Surviving Sepsis Campaign have seen a reduction in mortality rate for hospital-acquired severe sepsis. They may reduce this further by focusing on new approaches to diagnosing sepsis, especially at an early stage. Sepsis is a complicated syndrome with many physiological derangements and many emerging laboratory markers of sepsis have been proposed as adjuncts to clinical evaluation. The list includes cytokines, acute phase proteins, neutrophil activation markers, markers of abnormal coagulation and, recently, markers of suppression of both the innate and adaptive immune response. The perfect biomarker would accurately identify patients at risk of developing severe sepsis and then guide targeted therapy.

Interleukin-6 in surgery, trauma, and critical care part II: clinical implications

A variety of cytokines play a role in the inflammatory response. Interleukin-6 (IL-6)-type cytokines are released in response to tissue injury or an inflammatory stimulus, and act locally and systemically to generate a variety of physiologic responses. Interleukin-6 concentrations are elevated after surgery, trauma, and critical illness. The magnitude of IL-6 elevation correlates with the extent of tissue trauma/injury severity. Furthermore, there is an association between IL-6 elevation and adverse outcome. Interleukin-6 levels can also be used to stratify patients for therapeutic intervention.

Biomarkers for pediatric sepsis and septic shock

Sepsis is a clinical syndrome defined by physiologic changes indicative of systemic inflammation, which are likely attributable to documented or suspected infection. Septic shock is the progression of those physiologic changes to the extent that delivery of oxygen and metabolic substrate to tissues is compromised. Biomarkers have the potential to diagnose, monitor, stratify and predict outcome in these syndromes. C-reactive protein is elevated in inflammatory and infectious conditions and has long been used as a biomarker indicating infection. Procalcitonin has more recently been shown to better distinguish infection from inflammation. Newer candidate biomarkers for infection include IL-18 and CD64. Lactate facilitates the diagnosis of septic shock and the monitoring of its progression. Multiple stratification biomarkers based on genome-wide expression profiling are under active investigation and present exciting future possibilities.