Diagnostic accuracy of sTREM-1 to identify infection in critically ill patients with systemic inflammatory response syndrome

Diagnostic and prognostic predictive values of circulating sTREM-1 in sepsis: A meta-analysis

BACKGROUND

With the increasing studies regarding the diagnostic value of soluble triggering receptor expressed on myeloid cells (sTREM)-1 in sepsis in recent years, it is essential to make an updated meta-analysis to explore the sepsis differentiation value of circulating sTREM-1 from systemic inflammatory response syndrome (SIRS). Recently, no meta-analysis was made to explore the prognostic predictive value of circulating sTREM-1 in sepsis. Thus, the present aimed to make meta-analyses to explore the diagnostic and prognostic predictive values of circulating sTREM-1 in sepsis.

METHODS

Articles published before March 2021 were searched in databases: PubMed, Web of Science, EMBASE, Medline and Google Scholar. After a summary of sensitivity, specificity, positive likelihood ratios (PLR), negative likelihood ratios (NLR), and diagnostic odds ratio (DOR), the receive-operating characteristics (SROC) curve were performed to summarize true positive (TP) and false positive (FP) rates. Q test and I² were used to explore heterogeneity between studies.

RESULTS

Circulating sTREM-1 showed a high sensitivity (0.85 (95% confidence interval (CI): 0.76-0.91)) and moderate specificity (0.79 (95% CI: 0.70-0.86)) to differentiate sepsis from SIRS. The study showed a high sensitivity (0.80 (95% CI: 0.66-0.89)) and moderate specificity (0.75 (95% CI: 0.69-0.81)) to predict 28-day mortality in sepsis.

CONCLUSION

In conclusion, the present study suggested that circulating sTREM-1 showed diagnostic and prognostic predictive values in sepsis.

Diagnostic value of neutrophil CD64, procalcitonin, and interleukin-6 in sepsis: a meta-analysis

Background

The aim of the study was to conduct a meta-analysis to evaluate the accuracy of neutrophil CD64, procalcitonin (PCT), and interleukin-6 (IL-6) as markers for the diagnosis of sepsis in adult patients.

Methods

Various databases were searched to collect published studies on the diagnosis of sepsis in adult patients using neutrophil CD64, PCT, and IL-6 levels. Utilizing the Stata SE 15.0 software, forest plots and the area under the summary receiver operating characteristic curves were drawn. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve (AUC) were calculated.

Results

Fifty-four articles were included in the study. The pooled sensitivity, specificity, and AUC of neutrophil CD64 for the diagnosis of sepsis were 0.88 (95% confidence interval [CI], 0.81–0.92), 0.88 (95% CI, 0.83–0.91), and 0.94 (95% CI, 0.91–0.96), respectively. The pooled sensitivity, specificity, and AUC of PCT for the diagnosis of sepsis were 0.82 (95% CI, 0.78–0.85), 0.78 (95% CI, 0.74–0.82), and 0.87 (95% CI, 0.83–0.89), respectively. Subgroup analysis showed that the AUC for PCT diagnosis of intensive care unit (ICU) sepsis was 0.86 (95% CI, 0.83–0.89) and the AUC for PCT diagnosis of non-ICU sepsis was 0.82 (95% CI, 0.78–0.85). The pooled sensitivity, specificity, and AUC of IL-6 for the diagnosis of sepsis were 0.72 (95% CI, 0.65–0.78), 0.70 (95% CI, 0.62–0.76), and 0.77 (95% CI, 0.73–0.80), respectively.

Conclusions

Of the three biomarkers studied, neutrophil CD64 showed the highest diagnostic value for sepsis, followed by PCT, and IL-6. On the other hand, PCT showed a better diagnostic potential for the diagnosis of sepsis in patients with severe conditions compared with that in patients with non-severe conditions.

Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in neonatal sepsis

BACKGROUND

Efficient and accurate diagnosis of neonatal sepsis is challenging. The potential impact for a reduction in morbidity and mortality as well as antibiotic usage has stimulated the ongoing search for biomarkers of early sepsis. The objective of this pilot study was to quantify the levels of sTREM-1 and correlate with blood cultures and inflammatory markers in neonates evaluated for sepsis.

METHODS

Neonates with suspected sepsis were enrolled (n = 83; Preterm n = 35; Term n = 48). Routine bloods for sepsis evaluation were included and plasma sTREM-1 levels were quantified by ELISA.

RESULTS

Term and preterm neonates (n = 83; Preterm n = 35; Term n = 48) were enrolled and 16 neonates had positive blood cultures (preterm n = 15; term n = 1). sTREM-1 levels were not significantly different in infants with culture-positive or culture-negative sepsis (356 ± 218 pg/mL and 385 ± 254 pg/mL respectively). The immature-to-total granulocyte (I/T) ratio showed a significant positive correlation with sTREM-1 in the preterm group with positive blood cultures. Additionally, sTREM-1 showed a positive correlation with CRP in the preterm group with negative blood cultures.

CONCLUSIONS

sTREM-1 was associated with traditional markers of inflammation (I/T ratio and CRP). However, in this cohort sTREM-1 did not improve the early detection of neonatal culture-positive 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.

SIRS Triggered by Acute Right Ventricular Function, Mimicked Septic Shock

Background

The systemic inflammatory response syndrome (SIRS) is a complex immune response which can be precipitated by non-infectious aetiologies such as trauma, burns or pancreatitis. Addressing the underlying cause is crucial because it can be associated with increased mortality. Although the current literature associates chronic heart failure with SIRS, acute right ventricular dysfunction has not previously been reported to trigger SIRS. This case report describes the presentation of acute right ventricular dysfunction that triggered SIRS and mimicked septic shock.

Case presentation

A 70-year-old male presented to the Intensive Care Unit (ICU) with elevated inflammatory markers and refractory hypotension after a robotic-assisted laparoscopic radical choledochectomy with pancreaticoduodenectomy. Septic shock was misdiagnosed, and he was later found to have a pulmonary embolus. Thrombectomy and antimicrobials had no significant efect on lowering the elevated inflammatory markers or improving the persistent hypotension. Through Point of Care Ultrasound (POCUS), right ventricular dysfunction was diagnosed. Treatment with intravenous milrinone improved blood pressure, normalised inflammatory markers and led to a prompt discharge from the ICU.

Conclusion

Acute right ventricular dysfunction can trigger SIRS, which may mimic septic shock and delay appropriate treatment.

An immunohistochemical study of the diagnostic value of TREM-1 as marker for fatal sepsis cases

Triggering receptor expressed on myeloid cells-1 (TREM-1) is produced and up-regulated by exposure of myeloid cells to lipopolysaccharides or other components of either bacterial or fungal origin, which causes it to be strongly expressed on phagocytes that accumulate in inflamed areas. Because TREM-1 participates in septic shock and in amplifying the inflammatory response to bacterial and fungal infections, we believe it could be an immunohistochemical marker for postmortem diagnosis of sepsis. We tested the anti-TREM-1 antibody in 28 cases of death by septic shock and divided them into two groups. The diagnosis was made according to the criteria of the Surviving Sepsis Campaign. In all cases, blood cultures were positive. The first group was comprised subjects that presented high ante-mortem serum procalcitonin and the soluble form of TREM-1 (s-TREM-1) values. The second group comprised subjects in which s-TREM-1 was not measured ante-mortem. We used samples of brain, heart, lung, liver and kidney for each case to test the anti-TREM-1 antibody. A semiquantitative evaluation of the immunohistochemical findings was made. In lung samples, we found immunostaining in the cells of the monocyte line in 24 of 28 cases, which suggests that TREM-1 is produced principally by cells of the monocyte line. In liver tissue, we found low TREM-staining in the hepatocyte cytoplasm, duct epithelium, the portal-biliary space and blood vessel. In kidney tissue samples, we found the TREM-1 antibody immunostaining in glomeruli and renal tubules. We also found TREM-1 staining in the lumen of blood vessels. Immunohistochemical staining using the anti-TREM-1 antibody can be useful for postmortem diagnosis of sepsis.

Soluble TREM-1 Serum Level can Early Predict Mortality of Patients with Sepsis, Severe Sepsis and Septic Shock

Early prognostic prediction of sepsis is essential in adjusting therapeutic protocols to prevent deterioration and reduce mortality. We compared the predictive value of the serum concentration of the soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) for 28-day mortality and for the development of severe sepsis or septic shock on the third day with the levels of interleukin (IL)-6, C-reactive protein (CRP) and procalcitonin (PCT). The study was conducted on 85 patients with sepsis. sTREM-1, CRP, PCT and IL-6 concentrations were measured upon study inclusion (day 0) and on days 1, 2, 3 and 5. APACHE II, SAPS II and SOFA scores were analyzed. The sTREM-1 levels (pg/ml) were higher in non-survivors than in survivors at admission (773 vs. 391, p < 0.001) and on days 1, 2, 3 and 5. In predicting the development of severe sepsis, the highest AUCs were found for PCT (0.744, 95% CI 0.638–0.85) and sTREM-1 (0.664, 95% CI 0.55–0.778); and in septic shock prediction, for PCT (0.766, 95% CI 0.665–0.867) and IL-6 (0.707, 95% CI 0.595–0.819). sTREM-1 positively correlated with APACHE II, SAPS II and SOFA scores. At inclusion, significant AUC for predicting 28-day mortality was 0.772 for the sTREM-1 (95% CI 0.672–0.871), 0.858 for APACHE II (95% CI 0.768–0.948), 0.847 for SAPS II (95% CI 0.733–0.96), 0.806 for SOFA score (95% CI 0.698–0.915). sTREM-1 can early predict the 28-day sepsis mortality, although its effectiveness is lower in comparison with clinical severity scores.

Diagnostic accuracy of procalcitonin, neutrophil-lymphocyte count ratio, C-reactive protein, and lactate in patients with suspected bacterial sepsis

Background

Early recognition is a key factor to achieve improved outcomes for septic patients. Combinations of biomarkers, as opposed to single ones, may improve timely diagnosis and survival. We investigated the performance characteristics of sepsis biomarkers, alone and in combination, for diagnosis of verified bacterial sepsis using Sepsis-2 and Sepsis-3 criteria, respectively.

Methods

Procalcitonin (PCT), neutrophil-lymphocyte count ratio (NLCR), C-reactive protein (CRP), and lactate were determined in a total of 1,572 episodes of adult patients admitted to the emergency department on suspicion of sepsis. All sampling were performed prior to antibiotic administration. Discriminant analysis was used to construct two composite biomarkers consisting of linear combinations of the investigated biomarkers, one including three selected biomarkers (i.e., NLCR, CRP, and lactate), and another including all four (i.e., PCT, NLCR, CRP, and lactate). The diagnostic performances of the composite biomarkers as well as the individual biomarkers were compared using the area under the receiver operating characteristic curve (AUC).

Results

For diagnosis of bacterial sepsis based on Sepsis-3 criteria, the AUC for PCT (0.68; 95% CI 0.65–0.71) was comparable to the AUCs for the both composite biomarkers. Using the Sepsis-2 criteria for bacterial sepsis diagnosis, the AUC for the NLCR (0.68; 95% CI 0.65–0.71) but not for the other single biomarkers, was equal to the AUCs for the both composite biomarkers. For diagnosis of severe bacterial sepsis or septic shock based on the Sepsis-2 criteria, the AUCs for both composite biomarkers were significantly greater than those of the single biomarkers (0.85; 95% CI 0.82–0.88 for the composite three-biomarker, and 0.86; 95% CI 0.83–0.89 for the composite four-biomarker).

Conclusions

Combinations of biomarkers can improve the diagnosis of verified bacterial sepsis in the most critically ill patients, but in less severe septic conditions either the NLCR or PCT alone exhibit equivalent performance.

Soluble triggering receptor expressed on myeloid cell-1 (sTREM-1): a potential biomarker for the diagnosis of infectious diseases

Sensitive and useful biomarkers for the diagnosis and prognosis of infectious diseases have been widely developed. An example of these biomarkers is triggering receptor expressed on myeloid cell-1 (TREM-1), which is a cell surface receptor expressed on monocytes/macrophages and neutrophils. TREM-1 amplifies inflammation by activating the TREM-1/DAP12 pathway. This pathway is triggered by the interaction of TREM-1 with ligands or stimulation by bacterial lipopolysaccharide. Consequently, pro-inflammatory cytokines and chemokines are secreted. Soluble TREM-1 (sTREM-1) is a special form of TREM-1 that can be directly tested in human body fluids and well-known biomarker for infectious diseases. sTREM-1 level can be potentially used for the early diagnosis and prognosis prediction of some infectious diseases, including infectious pleural effusion, lung infections, sepsis, bacterial meningitis, viral infections (e.g., Crimean Congo hemorrhagic fever and dengue fever), fungal infections (e.g., Aspergillus infection), and burn-related infections. sTREM-1 is a more sensitive and specific biomarker than traditional indices, such as C-reactive protein and procalcitonin levels, for these infectious diseases. Therefore, sTREM-1 is a feasible biomarker for the targeted therapy and rapid and early diagnosis of infectious diseases.

Biomarkers for diagnosis of sepsis in patients with systemic inflammatory response syndrome: a systematic review and meta-analysis

Background

Sepsis is one of the most common diseases that seriously threaten human health. Although a large number of markers related to sepsis have been reported in the last two decades, the diagnostic accuracy of these biomarkers remains unclear due to the lack of similar baselines among studies. Therefore, we conducted a large systematic review and meta-analysis to evaluate the diagnostic value of biomarkers from studies that included non-infectious systemic inflammatory response syndrome patients as a control group.

Methods

We searched Medline, Embase and the reference lists of identified studies beginning in April 2014. The last retrieval was updated in September 2016.

Results

Ultimately, 86 articles fulfilled the inclusion criteria. Sixty biomarkers and 10,438 subjects entered the final analysis. The areas under the receiver operating characteristic curves for the 7 most common biomarkers, including procalcitonin, C-reactive protein, interleukin 6, soluble triggering receptor expressed on myeloid cells-1, presepsin, lipopolysaccharide binding protein and CD64, were 0.85, 0.77, 0.79, 0.85, 0.88, 0.71 and 0.96, respectively. The remaining 53 biomarkers exhibited obvious variances in diagnostic value and methodological quality.

Conclusions

Although some biomarkers displayed moderate or above moderate diagnostic value for sepsis, the limitations of the methodological quality and sample size may weaken these findings. Currently, we still lack an ideal biomarker to aid in the diagnosis of sepsis. In the future, biomarkers with better diagnostic value as well as a combined diagnosis using multiple biomarkers are expected to solve the challenge of the diagnosis of sepsis.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-3591-5) contains supplementary material, which is available to authorized users.

sTREM-1, sIL-2Rα, and IL-6, but not sCD163, might predict sepsis in polytrauma patients: a prospective cohort study

BACKGROUND

To investigate whether sTREM-1, sIL-2Rα, sCD163, and IL-6 predict septic complications following polytrauma. Prospective observational study in a university hospital intensive care unit.

METHODS

Blood samples were drawn on admission, 24 and 48 h after the injury from 64 adult polytrauma patients. The occurence of infectious complications was investigated. The sepsis-free rates for the multiple trauma patients were considered as end points in the Kaplan-Meier plot analysis.

RESULTS

Upon admission, sIL-2Rα mean values were higher in the T group compared to the T&S patients (1789 ± 1027 pg/mL versus 1280 ± 605 pg/mL, p = 0.02). The initial mean values of sTREM-1, IL-6, and sCD163 did not discriminate between the T and T&S groups patients (p > 0.05). sTREM-1 cutoff was 62 pg/mL: the sepsis-free rates differed significantly between the patients with sTREM-1 concentrations lower and higher than the cutoff (80 versus 48 %, p < 0.01). From the patients with serum sIL-2Rα ≥1593 pg/mL, 86 % did not present sepsis; for sIL-2Rα values in the range 946-1593 pg/mL, the sepsis-free rate was 68 %, while from the patients with sIL-2Rα <945 pg/mL, only 40 % remained sepsis-free (p = 0.05). sCD163 cutoff of 1000 ng/mL did not discriminate between the patients (76 versus 64 %, p = 0.28). For IL-6, the sepsis-free rates differed significantly between the patients with concentrations lower and higher than 400 pg/mL (78 versus 38 %, p < 0.01).

CONCLUSIONS

sTREM-1, sIL-2Rα, and IL-6, but not CD163, may be used as prognostic markers for the occurrence of sepsis in multiple trauma patients.

LEVEL OF EVIDENCE

Level II-Diagnostic tests and criteria.

Prospective Evaluation of Procalcitonin, Soluble Triggering Receptor Expressed on Myeloid Cells-1 and C-Reactive Protein in Febrile Patients with Autoimmune Diseases

Background

Both procalcitonin (PCT) and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) have been investigated separately as indicators of infection in patients with autoimmune diseases. Our study simultaneously evaluated both PCT and sTREM-1 along with C-reactive protein (CRP) in febrile patients with autoimmune diseases.

Methods

Fifty-nine patients were enrolled in the study. The patients were categorized into the infection group (n = 24) or the disease flare group (n = 35). sTREM-1, PCT and CRP concentrations at fever onset were compared between the two groups of patients.

Results

sTREM-1 and CRP did not differ between the two groups. PCT [median (range), ng/ml] was higher in the infection group than in the disease flare group [0.53 (0.02–12.85) vs. 0.12 (0.02–19.23), p = 0.001]. The area under the receiver-operating characteristic (ROC) for diagnosis of infection was 0.75 for PCT (p = 0.001), 0.63 for CRP (p = 0.09) and 0.52 for sTREM-1 (p = 0.79). Using 0.2 ng/ml as the cutoff value for PCT, sensitivity was 0.75 and specificity was 0.77. Negative predictive values for PCT were 92%, 87% and 82% for a prevalence of infection of 20%, 30%, and 40%, respectively. Neither immunosuppressants nor biomodulators affected the level of the three biomarkers. However, in patients treated with corticosteroids, the levels of sTREM-1 and CRP were significantly decreased compared with the untreated patients.

Conclusions

Setting PCT at a lower cutoff value could provide useful information on excluding infection in febrile patients with autoimmune diseases. The possible effect of corticosteroids on the level of sTREM-1 as an infection marker deserves further study.

High Expression Levels of Trigger Receptor Expressed on Myeloid Cells-1 on Neutrophils Associated with Increased Severity of Acute Pancreatitis in Mice

Triggering receptor expressed on myeloid cells (TREM)-1 expression on neutrophils is associated with inflammation and infection. However, the dynamic changes of the TREM-1 expression on neutrophils have not been clarified in inflammatory acute pancreatitis (AP). The aim of this study was to longitudinally investigate the TREM-1 expression on peripheral blood and peritoneal neutrophils and its relationship with the levels of plasma cytokines and disease severity in a mouse model of AP following injection with varying doses of L-arginine to induce mild AP (MAP) or severe AP (SAP). The results indicated that induction of MAP or SAP was associated with moderate and severe pancreatic tissue damage and varying levels of serum and peritoneal fluid amylase as well as survival rates in mice. In comparison with that in the healthy controls, significantly increased percentages of peripheral blood and peritoneal fluid CD14-TREM-1(+) neutrophils and higher levels of TREM-1 mRNA transcripts in peripheral blood nuclear cells were detected in the MAP and SAP mice, particularly in the SAP mice. Higher levels of plasma tumor necrosis factor (TNF)-α and granulocyte-macrophage colony stimulating factor (GM-CSF), but lower levels of plasma interleukin (IL)-10, were detected in the MAP and SAP mice at varying time points post induction. The percentages of peripheral blood CD14-TREM-1(+) neutrophils were correlated positively with the levels of TNF-α, GM-CSF, and amylase as well as the pathogenic scores, but negatively with the levels of IL-10 in the AP mice. Therefore, TREM-1(+) neutrophils may participate in the pathogenesis of AP and serve as a biomarker for evaluating the severity of AP.

Host response biomarkers in sepsis: overview on sTREM-1 detection

The diagnosis of sepsis, and especially its differentiation from sterile inflammation, may be challenging. TREM-1, the triggering receptor expressed on myeloid cells-1, is an amplifier of the innate immune response. Its soluble form acts as a decoy for the natural TREM-1 ligand and dampens its activation. In this chapter, we review the numerous studies that have evaluated the usefulness of sTREM-1 concentration determination for the diagnosis and the prognosis evaluation of sepsis or localized infection. Nowadays, sandwich ELISA kits are available and the assay is described.

Biomarkers for sepsis: a review with special attention to India

Sepsis is a serious infection and still a common cause of morbidity and mortality in resource-limited settings such as India. Even when microbiologic diagnostics are available, bacteremia is only identified in a proportion of patients who present with sepsis and bloodstream infections. Biomarkers have been used in a variety of disease processes and can help aid in diagnosing bacterial infections. There have been numerous biomarkers investigated to aid with diagnosis and prognostication in sepsis with the majority suffering from lack of sensitivity or specificity. Procalcitonin has been heralded as the biomarker that holds the most promise for bloodstream infections. Data are emerging in India, and in this review, we focus on the current data of biomarkers in sepsis with particular attention to how biomarkers could be used to augment diagnosis and treatment in India.

Sepsis: multiple abnormalities, heterogeneous responses, and evolving understanding

Sepsis represents the host's systemic inflammatory response to a severe infection. It causes substantial human morbidity resulting in hundreds of thousands of deaths each year. Despite decades of intense research, the basic mechanisms still remain elusive. In either experimental animal models of sepsis or human patients, there are substantial physiological changes, many of which may result in subsequent organ injury. Variations in age, gender, and medical comorbidities including diabetes and renal failure create additional complexity that influence the outcomes in septic patients. Specific system-based alterations, such as the coagulopathy observed in sepsis, offer both potential insight and possible therapeutic targets. Intracellular stress induces changes in the endoplasmic reticulum yielding misfolded proteins that contribute to the underlying pathophysiological changes. With these multiple changes it is difficult to precisely classify an individual's response in sepsis as proinflammatory or immunosuppressed. This heterogeneity also may explain why most therapeutic interventions have not improved survival. Given the complexity of sepsis, biomarkers and mathematical models offer potential guidance once they have been carefully validated. This review discusses each of these important factors to provide a framework for understanding the complex and current challenges of managing the septic patient. Clinical trial failures and the therapeutic interventions that have proven successful are also discussed.

Diagnostic value of soluble triggering receptor expressed on myeloid cells-1 in critically-ill, postoperative patients with suspected sepsis

INTRODUCTION

: The lack of specific clinical manifestations for sepsis frequently leads to delayed diagnosis. Identification of sensitive and specific indicators that can be easily assessed, accurately reflect infection severity and prognosis and are clinically important in the differential diagnosis of sepsis, is of great significance. The purpose of this study was to evaluate the diagnostic and prognostic value of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in high selected, mostly postoperative patients with suspicion of sepsis.

METHODS

: Fifty-two consecutive patients hospitalized in a surgical intensive care unit with suspicion of infection included 14 patients with systemic inflammatory response syndrome (SIRS), 9 patients with sepsis, 14 patients with severe sepsis and 15 patients with septic shock. Within 12 hours after enrollment, plasma levels of sTREM-1, procalcitonin (PCT), tumor necrosis factor (TNF)-α, interleukin-6 and C-reactive protein were measured and compared between subgroups to elucidate their diagnostic and prognostic values.

RESULTS

: Plasma sTREM-1 levels were higher in patients with sepsis than in patients with SIRS (111.7 versus 64.1 pg/mL, P < 0.05), with sensitivity, specificity and a predictive value higher than those of PCT and TNF-α. Plasma sTREM-1 levels were significantly different between the sepsis, severe sepsis and septic shock subgroups (P < 0.001). For the receiver operating characteristic for predicting death, the area under the curve of sTREM-1 was 0.861, similar to that of TNF-α, blood lactate and PCT (0.848, 0.719 and 0.706, respectively).

CONCLUSIONS

: In postoperative patients, plasma levels of sTREM-1 and TNF-α could differentiate sepsis from SIRS. sTREM levels also reflected the severity of sepsis and were noninferior for prognosis compared with other biochemical indexes.

Clinical application of sepsis biomarkers

Sepsis is one of the leading causes of death in the critically ill. Early diagnosis is important to avoid delay in instituting appropriate treatment. However, diagnosis can be delayed because of difficulty in interpreting clinical features. Sepsis biomarkers can aid early diagnosis. This article reviews the application of readily available biomarkers for diagnosis of sepsis, for predicting prognosis, and for antibiotic stewardship. 178 biomarkers are described in the literature--ranging from specimen cultures, which lack sensitivity and specificity for early diagnosis of sepsis, to biomarkers such as C-reactive protein, procalcitonin, and genetic biomarkers, which have their own limitations. Future research will mainly focus on use of more than one biomarker, but the main problem in sepsis biomarker research seems to be a lack of a recommended biomarker.

Procalcitonin as a diagnostic marker for sepsis: a systematic review and meta-analysis

BACKGROUND

Procalcitonin is a promising marker for identification of bacterial infections. We assessed the accuracy and clinical value of procalcitonin for diagnosis of sepsis in critically ill patients.

METHODS

We searched Medline, Embase, ISI Web of Knowledge, the Cochrane Library, Scopus, BioMed Central, and Science Direct, from inception to Feb 21, 2012, and reference lists of identified primary studies. We included articles written in English, German, or French that investigated procalcitonin for differentiation of septic patients--those with sepsis, severe sepsis, or septic shock--from those with a systemic inflammatory response syndrome of non-infectious origin. Studies of healthy people, patients without probable infection, and children younger than 28 days were excluded. Two independent investigators extracted patient and study characteristics; discrepancies were resolved by consensus. We calculated individual and pooled sensitivities and specificities. We used I(2) to test heterogeneity and investigated the source of heterogeneity by metaregression.

FINDINGS

Our search returned 3487 reports, of which 30 fulfilled the inclusion criteria, accounting for 3244 patients. Bivariate analysis yielded a mean sensitivity of 0 · 77 (95% CI 0 · 72-0 · 81) and specificity of 0 · 79 (95% CI 0 · 74-0 · 84). The area under the receiver operating characteristic curve was 0 · 85 (95% CI 0 · 81-0 · 88). The studies had substantial heterogeneity (I(2)=96%, 95% CI 94-99). None of the subgroups investigated--population, admission category, assay used, severity of disease, and description and masking of the reference standard--could account for the heterogeneity.

INTERPRETATION

Procalcitonin is a helpful biomarker for early diagnosis of sepsis in critically ill patients. Nevertheless, the results of the test must be interpreted carefully in the context of medical history, physical examination, and microbiological assessment.

FUNDING

Ministry of Education and Research, the Deutsche Forschungsgemeinschaft, Thuringian Ministry for Education, Science and Culture, the Thuringian Foundation for Technology, Innovation and Research, and the German Sepsis Society.

New approaches to sepsis: molecular diagnostics and biomarkers

Sepsis is among the most common causes of death in hospitals. It arises from the host response to infection. Currently, diagnosis relies on nonspecific physiological criteria and culture-based pathogen detection. This results in diagnostic uncertainty, therapeutic delays, the mis- and overuse of antibiotics, and the failure to identify patients who might benefit from immunomodulatory therapies. There is a need for new sepsis biomarkers that can aid in therapeutic decision making and add information about screening, diagnosis, risk stratification, and monitoring of the response to therapy. The host response involves hundreds of mediators and single molecules, many of which have been proposed as biomarkers. It is, however, unlikely that one single biomarker is able to satisfy all the needs and expectations for sepsis research and management. Among biomarkers that are measurable by assays approved for clinical use, procalcitonin (PCT) has shown some usefulness as an infection marker and for antibiotic stewardship. Other possible new approaches consist of molecular strategies to improve pathogen detection and molecular diagnostics and prognostics based on transcriptomic, proteomic, or metabolic profiling. Novel approaches to sepsis promise to transform sepsis from a physiologic syndrome into a group of distinct biochemical disorders and help in the development of better diagnostic tools and effective adjunctive sepsis therapies.

Accuracy of plasma sTREM-1 for sepsis diagnosis in systemic inflammatory patients: a systematic review and meta-analysis

Introduction

Early diagnosis of sepsis is vital to the clinical course and outcome of septic patients. Recently, soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) appears to be a potential marker of infection. The objective of this systematic review and meta-analysis was to evaluate the accuracy of plasma sTREM-1 for sepsis diagnosis in systemic inflammatory patients.

Methods

A systematic literature search of PubMed, Embase and Cochrane Central Register of Controlled Trials was performed using specific search terms (up to 15 October 2012). Studies were included if they assessed the accuracy of plasma sTREM-1 for sepsis diagnosis in adult patients with systemic inflammatory response syndrome (SIRS) and provided sufficient information to construct a 2 X 2 contingency table.

Results

Eleven studies with a total of 1,795 patients were included. The pooled sensitivity and specificity was 79% (95% confidence interval (CI), 65 to 89) and 80% (95% CI, 69 to 88), respectively. The positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 4.0 (95% CI, 2.4 to 6.9), 0.26 (95% CI, 0.14 to 0.48), and 16 (95% CI, 5 to 46), respectively. The area under the curve of the summary receiver operator characteristic was 0.87 (95% CI, 0.84 to 0.89). Meta-regression analysis suggested that patient sample size and assay method were the main sources of heterogeneity. Publication bias was suggested by an asymmetrical funnel plot (P = 0.02).

Conclusions

The present meta-analysis showed that plasma sTREM-1 had a moderate diagnostic performance in differentiating sepsis from SIRS. Accordingly, plasma sTREM-1 as a single marker was not sufficient for sepsis diagnosis in systemic inflammatory patients.

Value of soluble TREM-1, procalcitonin, and C-reactive protein serum levels as biomarkers for detecting bacteremia among sepsis patients with new fever in intensive care units: a prospective cohort study

Background

The purpose of this study was to explore the diagnostic value of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1), procalcitonin (PCT), and C-reactive protein (CRP) serum levels for differentiating sepsis from SIRS, identifying new fever caused by bacteremia, and assessing prognosis when new fever occurred.

Methods

We enrolled 144 intensive care unit (ICU) patients: 60 with systemic inflammatory response syndrome (SIRS) and 84 with sepsis complicated by new fever at more than 48 h after ICU admission. Serum sTREM-1, PCT, and CRP levels were measured on the day of admission and at the occurrence of new fever (>38.3°C) during hospitalization. Based on the blood culture results, the patients were divided into a blood culture-positive bacteremia group (33 patients) and blood culture-negative group (51 patients). Based on 28-day survival, all patients, both blood culture-positive and -negative, were further divided into survivor and nonsurvivor groups.

Results

On ICU day 1, the sepsis group had higher serum sTREM-1, PCT, and CRP levels compared with the SIRS group (P <0.05). The areas under the curve (AUC) for these indicators were 0.868 (95% CI, 0.798–0.938), 0.729 (95% CI, 0.637–0.821), and 0.679 (95% CI, 0.578–0.771), respectively. With 108.9 pg/ml as the cut-off point for serum sTREM-1, sensitivity was 0.83 and specificity was 0.81. There was no statistically significant difference in serum sTREM-1 or PCT levels between the blood culture-positive and -negative bacteremia groups with ICU-acquired new fever. However, the nonsurvivors in the blood culture-positive bacteremia group had higher levels of serum sTREM-1 and PCT (P <0.05), with a prognostic AUC for serum sTREM-1 of 0.868 (95% CI, 0.740–0.997).

Conclusions

Serum sTREM-1, PCT, and CRP levels each have a role in the early diagnosis of sepsis. Serum sTREM-1, with the highest sensitivity and specificity of all indicators studied, is especially notable. sTREM-1, PCT, and CRP levels are of no use in determining new fever caused by bacteremia in ICU patients, but sTREM-1 levels reflect the prognosis of bacteremia.

Trial registration

ClinicalTrial.gov identifier NCT01410578

Immune regulation of procalcitonin: a biomarker and mediator of infection

Procalcitonin (PCT) has recently emerged as a powerful biomarker for an early and accurate diagnosis of bacterial infection. Here we summarize our current understanding of the expression pathways of PCT, its potential cellular sources including immune cells, and factors inducing its secretion. Also addressed is the significance of increased blood PCT concentration, which may allow this molecule not only to act as a clinical biomarker but also as an active participant in the development and progression of infectious processes. Experimental approaches to delineate a better understanding of PCT functions, molecular pathways that modulate its expression and therapeutic opportunities to curtail its biological actions are discussed, as well.

sTREM-1 as a Prognostic Marker of Postoperative Complications in Cardiac Surgery

Cell-activating receptor TREM-1 (triggering receptor expressed on myeloid cells 1) regulates congenital immune response and contributes to systemic inflammatory response syndrome (SIRS) development. It is able to multiply cytokine production while stimulated together with the main receptors of the congenital immune system. The purpose of the paper is to study the potential use of soluble TREM-1 (sTREM-1) as a marker of intensive SIRS and a criterion for postoperative complications prediction following on-pump coronary artery bypass surgery (CABG). Results show that early postoperative sTREM-1 concentrations demonstrate their potential prognostic value regarding SIRS-associated complications.

Triggering receptor expressed on myeloid cell 1

Sepsis is a common cause of morbidity and mortality in intensive care units. There is no gold standard for diagnosing sepsis because clinical and laboratory signs are neither sensitive nor specific enough and microbiological studies often show negative results. The triggering receptor expressed on myeloid cell 1 (TREM-1) is a member of the immunoglobulin superfamily. Its expression is upregulated on phagocytic cells in the presence of bacteria or fungi. This article reports on the potential usefulness of the assessment of the soluble form of TREM-1 in biologic fluids in the diagnosis of infection.

Diagnostic accuracy of HMGB-1, sTREM-1, and CD64 as markers of sepsis in patients recently admitted to the emergency department

OBJECTIVES

The objectives were to evaluate the diagnostic accuracy for sepsis in an emergency department (ED) population of the cluster of differentiation-64 (CD64) glycoprotein expression on the surface of neutrophils (nCD64), serum levels of soluble triggering receptor expressed on myeloid cells-1 (s-TREM-1), and high-mobility group box-1 protein (HMGB-1).

METHODS

Patients with any of the following as admission diagnosis were enrolled: 1) suspected infection, 2) fever, 3) delirium, or 4) acute hypotension of unexplained origin within 24 hours of ED presentation. Levels of nCD64, HMGB-1, and s-TREM-1 were measured within the first 24 hours of the first ED evaluation. Baseline clinical data, Sepsis-related Organ Failure Assessment (SOFA) score, Acute Physiology and Chronic Health Evaluation (APACHE II) score, daily clinical and microbiologic information, and 28-day mortality rate were collected. Because there is not a definitive criterion standard for sepsis, the authors used expert consensus based on clinical, microbiologic, laboratory, and radiologic data collected for each patient during the first 7 days of hospitalization. This expert consensus defined the primary outcome of sepsis, and the primary data analysis was based in the comparison of sepsis versus nonsepsis patients. The cut points to define sensitivity and specificity values, as well as positive and negative likelihood ratios (LRs) for the markers related to sepsis diagnosis, were determined using receiver operative characteristics (ROC) curves. The patients in this study were a prespecified nested subsample population of a larger study.

RESULTS

Of 631 patients included in the study, 66% (95% confidence interval [CI] = 62% to 67%, n = 416) had sepsis according with the expert consensus diagnosis. Among these sepsis patients, SOFA score defined 67% (95% CI = 62% to 71%, n = 277) in severe sepsis and 1% (95% CI = 0.3% to 3%, n = 6) in septic shock. The sensitivities for sepsis diagnosis were CD64, 65.8% (95% CI = 61.1% to 70.3%); HMGB-1, 57.5% (95% CI = 52.7% to 62.3%); and s-TREM-1, 60% (95% CI = 55.2% to 64.7%). The specificities were CD64, 64.6% (95% CI = 57.8% to 70.8%), HMGB-1, 57.8% (95% CI = 51.1% to 64.3%), and s-TREM-1, 59.2% (95% CI = 52.5% to 65.6%). The positive LR (LR+) for CD64 was 1.85 (95% CI = 1.52 to 2.26) and the negative LR (LR-) was 0.52 (95% CI = 0.44 to 0.62]; for HMGB-1 the LR+ was 1.36 (95% CI = 1.14 to 1.63) and LR- was 0.73 (95% CI = 0.62 to 0.86); and for s-TREM-1 the LR+ was 1.47 (95% CI = 1.22 to 1.76) and the LR- was 0.67 (95% CI = 0.57 to 0.79).

CONCLUSIONS

In this cohort of patients suspected of having any infection in the ED, the accuracy of nCD64, s-TREM-1, and HMGB-1 was not significantly sensitive or specific for diagnosis of sepsis.

Dynamic changes of serum soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) reflect sepsis severity and can predict prognosis: a prospective study

BACKGROUND

We examined the utility of serum levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) for the diagnoses, severity assessments, and predicting the prognoses of patients with sepsis and compared sTREM-1 values with those of C-reactive protein (CRP) and procalcitonin (PCT).

METHODS

Fifty-two patients with sepsis were included: 15 sepsis cases and 37 severe sepsis cases (severe sepsis + septic shock). Serum levels of sTREM-1, CRP, and PCT were determined on days 1, 3, 5, 7, 10, and 14 after admission to an ICU.

RESULTS

Serum sTREM-1 levels of patients with severe sepsis were significantly higher than for those with sepsis on day 1 (240.6 pg/ml vs. 118.3 pg/ml; P < 0.01), but CRP and PCT levels were not significantly different between the two groups. The area under an ROC curve for sTREM-1 for severe sepsis patients was 0.823 (95% confidence interval: 0.690-0.957). Using 222.5 pg/ml of sTREM-1 as the cut-off value, the sensitivity was 59.5%, the specificity was 93.3%, the positive predictive value was 95.6%, the negative predictive value was 48.3%, the positive likelihood ratio was 8.92, and the negative likelihood ratio was 0.434. Based on 28-day survivals, sTREM-1 levels in the surviving group showed a tendency to decrease over time, while they tended to gradually increase in the non-surviving group. sTREM-1 levels in the non-surviving group were higher than those in the surviving group at all time points, whereas CRP and PCT levels showed a tendency to decrease over time in both groups. sTREM-1 levels and Sequential Organ Failure Assessment (SOFA) scores were positively correlated (r = 0.443; P < 0.001), and this correlation coefficient was greater than the correlation coefficients for both CRP and PCT.

CONCLUSIONS

Serum sTREM-1 levels reflected the severity of sepsis more accurately than those of CRP and PCT and were more sensitive for dynamic evaluations of sepsis prognosis.