A 29-MRNA HOST RESPONSE WHOLE-BLOOD SIGNATURE IMPROVES PREDICTION OF 28-DAY MORTALITY AND 7-DAY INTENSIVE CARE UNIT CARE IN ADULTS PRESENTING TO THE EMERGENCY DEPARTMENT WITH SUSPECTED ACUTE INFECTION AND/OR SEPSIS

A 29-mRNA host response test to identify bacterial and viral infections and to predict 30-day mortality in emergency department patients with suspected infections: A prospective observational cohort study

INTRODUCTION

The goal of this study is to validate the accuracy of the 29-mRNA host response classifiers Inflammatix Bacterial-Viral-Non infected-3b (IMX-BVN-3b) and Severity-3b (IMX-SEV-3b) to identify bacterial and viral infections and to predict 30-day mortality in patients with suspected infections in the ED.

METHODS

This prospective observational cohort study enrolled patients with suspected infections in a tertiary ED. IMX-BVN-3b was compared to clinically forced and consensus adjudicated bacterial/viral infection status and IMX-SEV-3b was compared to 30-day mortality.

RESULTS

A total of 688 patients were enrolled. Using forced adjudication, the AUC for the diagnosis of bacterial infection by IMX-BVN-3b was 0.76 (95 % CI: 0.72 - 0.80). The AUC for the diagnosis of viral infections was 0.89 (95 %CI 0.84-0.95). IMX-SEV-3b had an AUC of 0.77 (95 % CI: 0.68 - 0.85) on 30-day mortality.

CONCLUSION

The 29-gene host response classifiers IMX-BVN-3b and IMX-SEV-3b identify viral and bacterial infections and predict 30-day mortality in patients with suspected infections in the ED.

Assessment of MeMed BV assays for differentiating between bacterial and viral respiratory infections

INTRODUCTION

Distinguishing bacterial from viral infections remains a challenge due to clinically indistinguishable presentations. Non-infectious conditions such as malignancy, pulmonary emboli and rheumatological conditions may also present with fever. Consequently, patients are often over-treated with antimicrobial agents or may not receive adequate therapy.

AREAS COVERED

This article provides a comprehensive review of a novel protein host-signature assay, the MeMed BV assay, that distinguishes bacterial from viral infections. The focus is on the use of the test in respiratory tract infections including assay performance characteristics, clinical profiles and data on cost-effectiveness. The changing landscape from the use of single inflammatory biomarkers, such as C-reactive protein, to alternative and diverse host signature biomarkers, is also discussed.

EXPERT OPINION

The MeMed BV assay is one of several novel host biomarkers that provide rapid results and demonstrate enhanced performance compared to single test biomarkers. This assay has been validated by a large number of carefully controlled clinical trials that demonstrate improved performance characteristics for distinguishing bacterial infections or combined bacterial/viral infections from viral or noninfectious causes of fever compared to C-reactive protein and procalcitonin. However, these trials may over-state assay performance as samples with equivocal band results are often not included in the statistical analysis. More real-world studies addressing clinical implementation of the MeMed BV assay or other biomarkers into ambulatory settings are needed.

A 29-mRNA host-response classifier identifies bacterial infections following liver transplantation - a pilot study

PURPOSE

Infections are common complications in patients following liver transplantation (LTX). The early diagnosis and prognosis of these infections is an unmet medical need even when using routine biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT). Therefore, new approaches are necessary.

METHODS

In a prospective, observational pilot study, we monitored 30 consecutive patients daily between days 0 and 13 following LTX using the 29-mRNA host classifier IMX-BVN-3b that determine the likelihood of bacterial infections and viral infections. True infection status was determined using clinical adjudication. Results were compared to the accuracy of CRP and PCT for patients with and without bacterial infection due to clinical adjudication.

RESULTS

Clinical adjudication confirmed bacterial infections in 10 and fungal infections in 2 patients. 20 patients stayed non-infected until day 13 post-LTX. IMX-BVN-3b bacterial scores were increased directly following LTX and decreased until day four in all patients. Bacterial IMX-BVN-3b scores detected bacterial infections in 9 out of 10 patients. PCT concentrations did not differ between patients with or without bacterial, whereas CRP was elevated in all patients with significantly higher levels in patients with bacterial infections.

CONCLUSION

The 29-mRNA host classifier IMX-BVN-3b identified bacterial infections in post-LTX patients and did so earlier than routine biomarkers. While our pilot study holds promise future studies will determine whether these classifiers may help to identify post-LTX infections earlier and improve patient management.

CLINICAL TRIAL NOTATION

German Clinical Trials Register: DRKS00023236, Registered 07 October 2020, https://drks.de/search/en/trial/DRKS00023236.

Profiling the dysregulated immune response in sepsis: overcoming challenges to achieve the goal of precision medicine

Sepsis is characterised by a dysregulated host immune response to infection. Despite recognition of its significance, immune status monitoring is not implemented in clinical practice due in part to the current absence of direct therapeutic implications. Technological advances in immunological profiling could enhance our understanding of immune dysregulation and facilitate integration into clinical practice. In this Review, we provide an overview of the current state of immune profiling in sepsis, including its use, current challenges, and opportunities for progress. We highlight the important role of immunological biomarkers in facilitating predictive enrichment in current and future treatment scenarios. We propose that multiple immune and non-immune-related parameters, including clinical and microbiological data, be integrated into diagnostic and predictive combitypes, with the aid of machine learning and artificial intelligence techniques. These combitypes could form the basis of workable algorithms to guide clinical decisions that make precision medicine in sepsis a reality and improve patient outcomes.

COMPARISON AMONG PRESEPSIN, PROCALCITONIN, AND C-REACTIVE PROTEIN IN PREDICTING BLOOD CULTURE POSITIVITY AND PATHOGEN IN SEPSIS PATIENTS

ABSTRACT

Background: Sepsis is caused by the invasion of the bloodstream by microorganisms from local sites of infection, leading to high mortality. This study aimed to compare the predictive ability of the biomarkers presepsin, procalcitonin (PCT), and C-reactive protein for bacteraemia. Methods: In this retrospective, multicentre study, a dataset of patients with sepsis who were prospectively enrolled between November 2017 and June 2021 was analyzed. The performances of the biomarkers for predicting positive blood cultures and infection with specific pathogens were assessed by the areas under the receiver operating characteristic curves (AUCs). The independent effects of the pathogen and foci of infection on presepsin and PCT levels were assessed by linear logistic regression models. Results: A total of 577 patients with 170 positive blood cultures (29.5%) were enrolled. The AUC achieved using PCT levels (0.856) was significantly higher than that achieved using presepsin (0.786, P = 0.0200) and C-reactive protein (0.550, P < 0.0001) levels in predicting bacteraemia. The combined analysis of PCT and presepsin levels led to a significantly higher AUC than the analysis of PCT levels alone for predicting blood culture positivity (0.877 vs. 0.856, P = 0.0344) and gram-negative bacteraemia (0.900 vs. 0.875, P = 0.0216). In a linear regression model, the elevated concentrations of presepsin and PCT were both independently related to Escherichia coli , Klebsiella species, Pseudomonas species, and Streptococcus species infections and Sequential Organ Failure Assessment score. Presepsin levels were also associated with Acinetobacter species and abdominal infection, and PCT levels were positively associated with other Enterobacteriaceae and negatively associated with respiratory infection. Combined analysis of presepsin and PCT levels provided a high sensitivity and specificity in identifying E. coli or Klebsiella species infection. Conclusions: Presepsin and PCT were promising markers for predicting bacteraemia and common pathogens at the time of sepsis onset with a synergistic effect.

Adverse outcomes and an immunosuppressed endotype in septic patients with reduced IFN-γ ELISpot

BACKGROUNDSepsis remains a major clinical challenge for which successful treatment requires greater precision in identifying patients at increased risk of adverse outcomes requiring different therapeutic approaches. Predicting clinical outcomes and immunological endotyping of septic patients generally relies on using blood protein or mRNA biomarkers, or static cell phenotyping. Here, we sought to determine whether functional immune responsiveness would yield improved precision.METHODSAn ex vivo whole-blood enzyme-linked immunosorbent spot (ELISpot) assay for cellular production of interferon γ (IFN-γ) was evaluated in 107 septic and 68 nonseptic patients from 5 academic health centers using blood samples collected on days 1, 4, and 7 following ICU admission.RESULTSCompared with 46 healthy participants, unstimulated and stimulated whole-blood IFN-γ expression was either increased or unchanged, respectively, in septic and nonseptic ICU patients. However, in septic patients who did not survive 180 days, stimulated whole-blood IFN-γ expression was significantly reduced on ICU days 1, 4, and 7 (all P < 0.05), due to both significant reductions in total number of IFN-γ-producing cells and amount of IFN-γ produced per cell (all P < 0.05). Importantly, IFN-γ total expression on days 1 and 4 after admission could discriminate 180-day mortality better than absolute lymphocyte count (ALC), IL-6, and procalcitonin. Septic patients with low IFN-γ expression were older and had lower ALCs and higher soluble PD-L1 and IL-10 concentrations, consistent with an immunosuppressed endotype.CONCLUSIONSA whole-blood IFN-γ ELISpot assay can both identify septic patients at increased risk of late mortality and identify immunosuppressed septic patients.TRIAL REGISTRYN/A.FUNDINGThis prospective, observational, multicenter clinical study was directly supported by National Institute of General Medical Sciences grant R01 GM-139046, including a supplement (R01 GM-139046-03S1) from 2022 to 2024.

Adverse Long-Term Outcomes and an Immune Suppressed Endotype in Sepsis Patients with Reduced Interferon-γELISpot: A Multicenter, Prospective Observational Study

BACKGROUND

Sepsis remains a major clinical challenge for which successful treatment requires greater precision in identifying patients at increased risk of adverse outcomes requiring different therapeutic approaches. Predicting clinical outcomes and immunological endotyping of septic patients has generally relied on using blood protein or mRNA biomarkers, or static cell phenotyping. Here, we sought to determine whether functional immune responsiveness would yield improved precision.

METHODS

An ex vivo whole blood enzyme-linked immunosorbent (ELISpot) assay for cellular production of interferon-γ (IFN-γ) was evaluated in 107 septic and 68 non-septic patients from five academic health centers using blood samples collected on days 1, 4 and 7 following ICU admission.

RESULTS

Compared with 46 healthy subjects, unstimulated and stimulated whole blood IFNγ expression were either increased or unchanged, respectively, in septic and nonseptic ICU patients. However, in septic patients who did not survive 180 days, stimulated whole blood IFNγ expression was significantly reduced on ICU days 1, 4 and 7 (all p<0.05), due to both significant reductions in total number of IFNγ producing cells and amount of IFNγ produced per cell (all p<0.05). Importantly, IFNγ total expression on day 1 and 4 after admission could discriminate 180-day mortality better than absolute lymphocyte count (ALC), IL-6 and procalcitonin. Septic patients with low IFNγ expression were older and had lower ALC and higher sPD-L1 and IL-10 concentrations, consistent with an immune suppressed endotype.

CONCLUSIONS

A whole blood IFNγ ELISpot assay can both identify septic patients at increased risk of late mortality, and identify immune-suppressed, sepsis patients.