Sepsis Biomarkers

Septic macrophages induce T cells immunosuppression in a cell-cell contact manner with the involvement of CR3

Background

In addition to excessive inflammation, immunosuppression has been recognized as a contributing factor to poor prognosis of sepsis. Although it has been reported that T cells can become functionally impaired during sepsis, the underlying mechanisms responsible for this phenomenon remain unclear. This study aims to elucidate the mechanisms by which macrophages induce immunosuppression in T cells.

Methods

In an in vivo setting, C57BL-6J mice were subjected to cecal ligation and puncture (CLP) with or without depletion of macrophages, and the functions of T cells were assessed. In vitro experiments involved direct co-culture or separate culture of T cells and septic macrophages using a transwell system, followed by analysis of T cell immunity. Additionally, a siRNA targeting CD18 on macrophages was utilized to investigate the role of complement receptor 3 (CR3).

Results

Both macrophages and T cells exhibited immunosuppression during sepsis. In the in vivo experiments, the absence of macrophages partially alleviated T cell immunosuppression, as evidenced by restored vitality, increased production of TNF-α and IFN-γ, elevated CD8+ T cell levels, and decreased CD25+ T cell levels. In the in vitro experiments, direct co-culture of T cells with septic macrophages resulted in diminished T cell immunity, which was improved when T cells and macrophages were separated by a chamber wall. The expression of CR3 (CD11b/CD18) was upregulated on septic macrophages, and silencing of CD18 led to decreased TNF-α production by T cells, reduced CD4+ T cell numbers, and increased CD25+ T cell numbers.

Conclusion

In sepsis, macrophages induce immunosuppression in T cells through direct cell-cell contact, with the involvement of CR3.

Accuracy of Pancreatic Stone Protein for diagnosis of sepsis in children admitted to pediatric intensive care or high-dependency care: a pilot study

BACKGROUND

Pancreatic Stone Protein (PSP) is one of the most promising diagnostic and prognostic markers. The aim of the study was to assess the accuracy of PSP, compared to C-Reactive Protein (CRP), and Procalcitonin (PCT) for sepsis diagnosis in pediatric patients. Furthermore, we explored the correlation of PSP levels with sepsis severity and organ failure measured with PELOD-2 score.

METHODS

Forty pediatric patients were enrolled following admission to pediatric intensive care, high dependency care or pediatric ward. PSP blood levels were measured in Emergency Department (nanofluidic point-of-care immunoassay; abioSCOPE, Abionic SA, Switzerland) on day 1, 2, 3, 5 and 7 from the onset of the clinical signs and symptoms of sepsis or SIRS. Inclusion criteria were: 1) patient age (1 month to 18 years old), 2) signs and symptoms of SIRS, irrespective of association with organ dysfunction. Exclusion criteria were: 1) hemato-oncological diseases and/or immunodeficiencies, 2) pancreatic diseases.

RESULTS

Septic patients showed higher PSP levels than those with non-infectious systemic inflammation. The optimal cut-off in diagnosis of sepsis for PSP at day 1 was 167 ng/ml resulted in a sensitivity of 59% (95% IC 36%-79%) and a specificity of 83% (95% IC 58%-96%) with an AUC of 0.636 for PSP in comparison to AUC of 0.722 for PCT and 0.503 for C-RP. ROC analysis for outcome (survival versus no survival) has showed AUC 0.814 for PSP; AUC 0.814 for PCT; AUC of 0.657 for C-RP.

CONCLUSIONS

PSP could distinguish sepsis from non-infectious systemic inflammation; however, our results need to be confirmed in larger pediatric population.

The Predictive Value of Heparin-Binding Protein and D-Dimer in Patients with Sepsis

Objective

To explore the serial measurement of heparin-binding protein and D-dimer in the prediction of 28-day mortality and efficacy evaluation of critically-ill patients with sepsis.

Methods

We recruited a total of 51 patients with sepsis in the ICU of our hospital. They were divided into a survival group or a death group according to their prognosis 28 days after treatment. The HBP and D-dimer levels in these patients were determined on the 1st (24h), 3rd, and 5th days. Besides, the sequential organ failure assessment (SOFA) score of these patients was recorded at admission. The patients in both groups were subjected to comparison regarding HBP and D-dimer levels and SOFA scores within 24h of admission. Additionally, a correlation between the levels of HBP and D-dimer and the SOFA score was statistically measured, while the predictive effectiveness of these factors for the prognosis of patients with sepsis was also determined. Moreover, the dynamic changes in HBP and D-dimer during the treatment of both groups were analyzed.

Results

The HBP and D-dimer levels and the SOFA scores in the survival group were considerably lower than those in the death group, and the differences were statistically significant (P<0.05). Additionally, the levels of HBP and D-dimer in sepsis patients were positively correlated with the SOFA score (P<0.05). The area under the curve (AUC) of HBP, D-dimer, and their combination in predicting the prognosis of patients with sepsis was 0.824, 0.771, and 0.830, respectively. Besides, the sensitivity and specificity of their combination in predicting the prognosis of patients with sepsis were 68.42% and 92.31%, respectively. The HBP and D-dimer levels presented a downward trend in the survival group during treatment, while they exhibited an upward trend in the death group.

Conclusion

HBP and D-dimer realize high predictive effectiveness for the prognosis of patients with sepsis, while the combined use of these two factors achieves superior effectiveness. Thus, they can be applied to the prediction of 28-day mortality and efficacy evaluation of sepsis patients.

Platelet‑related parameters as potential biomarkers for the prognosis of sepsis

Early diagnosis and accurate prognosis are key for reducing the fatality rate and medical expenses associated with sepsis. Platelets are involved in the delayed tissue injury that occurs during sepsis. Therefore, the aim of the present study was to investigate the usefulness of platelets and associated parameters as prognostic markers of sepsis. The present study collected patient samples based on The Third International Consensus Definitions for Sepsis and Septic Shock criteria. Platelet-associated parameters were detected by flow cytometry and their correlation with clinical scores and prognoses was analyzed. Considering the association between endothelial cells and platelet activation, levels of plasma tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and angiopoietin-2 (Ang-2) were analyzed by ELISA. The results showed significant differences in platelet P-selectin expression and phosphatidylserine exposure, mitochondrial membrane potential (Mmp)-Index values and plasma levels of TWEAK and Ang-2 between patients and healthy controls (P<0.05). Except for P-selectin and TWEAK levels, all parameters were correlated with clinical scores (acute physiology and chronic health evaluation II and sequential/sepsis-related organ failure assessment). Additionally, platelet Mmp-Index between admission and the end of therapy was only different in non-survivors (P<0.001) and platelet phosphatidylserine exposure was significantly lower in survivors (P=0.006). Therefore, of the parameters tested, the dynamic monitoring of phosphatidylserine exposure, platelet Mmp-Index values and plasma Ang-2 levels had the most potential for the assessment of disease severity and clinical outcomes.

The Value of Peripheral Blood Leukocyte Parameters in the Early Diagnosis and Clinical Prognosis of Sepsis

Background

Early diagnosis of sepsis is the key to timely, targeted treatment. Cell population data (CPD) has been widely used in many diseases, but its predictive value for early diagnosis and the clinical outcome of sepsis remains unclear. Therefore, this paper discusses whether peripheral blood leukocyte parameters can be used as predictive indicators for early diagnosis and the clinical outcome of sepsis.

Methods

A retrospective study of 45 patients with sepsis, 53 patients with nonseptic infections, and 86 healthy check-ups admitted to Gansu Provincial Hospital from January 2021 to June 2022 was done using a hematology analyzer.

Results

The results of LYMPH#, HFLC#, IG#, NE-WX, LY-WX, LY-WY, and MO-WX showed better diagnostic efficiency in the sepsis group and nonseptic infection group. When the seven differential leukocyte parameters were used to establish diagnostic models, the sensitivity and specificity were 82.20% and 77.40%, respectively. Correlation analysis showed that LYMPH# and HFLC# were positively correlated with PCT (P < 0.05). The clinical outcome of sepsis showed that the leukocyte parameters of discharged WBC and LY-X had better predictive efficacy. When the two differential leukocyte parameters were used to establish diagnostic models, the sensitivity and specificity were 90.90% and 100.00%. Cox regression analysis showed that leukocyte parameters of discharged WBC and LY-X were independent predictors of clinical outcomes (P < 0.05).

Conclusion

Leucocyte parameters HFLC#, IG#, NE-WX, LY-WX, LY-WY, and MO-WX had a certain auxiliary effect on the early diagnosis of sepsis leukocyte parameters of discharged WBC and LY-X were independent predictors of clinical outcomes in patients with sepsis. Therefore, peripheral blood leukocyte parameters may have predictive value for early diagnosis and the clinical outcome of sepsis, but large-scale retrospective studies are still needed to prove our preliminary results.

The Levels of Oxidized Phospholipids in High-Density Lipoprotein During the Course of Sepsis and Their Prognostic Value

Purpose

To examine the levels of 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero phosphatidylcholine (POVPC) and 1-palmitoyl-2-glutaroyl-sn-glycero-phosphatidylcholine (PGPC) (the oxidized phosphatidylcholines) in HDL during the course of sepsis and to evaluate their prognostic value.

Materials and Methods

This prospective cohort pilot study enrolled 25 septic patients and 10 healthy subjects from 2020 to 2021. The HDLs were extracted from patient plasmas at day 1, 3 and 7 after sepsis onset and from healthy plasmas (total 81 plasma samples). These HDLs were then subjected to examining POVPC and PGPC by using an ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) system. We further measured the levels of 38 plasma cytokines by Luminex and evaluated the correlation of HDL-POVPC level with these cytokines. Patients were further stratified into survivors and non-survivors to analyze the association of HDL-POVPC level with 28-day mortality.

Results

Septic patients exhibited significant increase of HDL-POVPC at day 1, 3 and 7 after sepsis onset (POVPC-D1, p=0.0004; POVPC-D3, p=0.033; POVPC-D7, p=0.004, versus controls). HDL-PGPC was detected only in some septic patients (10 of 25) but not in healthy controls. Septic patients showed a significant change of the plasma cytokines profile. The correlation assay showed that IL-15 and IL-18 levels were positively correlated with HDL-POVPC level, while the macrophage-derived chemokine (MDC) level was negatively correlated with HDL-POVPC level. Furthermore, HDL-POVPC level in non-survivors was significantly increased versus survivors at day 1 and 3 (POVPC-D1, p=0.002; POVPC-D3, p=0.003). Area under ROC curves of POVPC-D1 and POVPC-D3 in predicting 28-day mortality were 0.828 and 0.851. POVPC-D1and POVPC-D3 were the independent risk factors for the death of septic patients (p=0.046 and 0.035).

Conclusions

HDL-POVPC was persistently increased in the course of sepsis. POVPC-D1 and POVPC-D3 were significantly correlated with 28-mortality and might be valuable to predict poor prognosis.

Monocyte distribution width (MDW) as a screening tool for early detecting sepsis: a systematic review and meta-analysis

OBJECTIVES

Monocyte distribution has recently emerged as a promising biomarker of sepsis, especially in acute setting, such as Emergency Department and Intensive Care Unit. This study aimed to evaluate the accuracy of monocyte distribution width (MDW) for early detecting patients with sepsis by performing a systemic review and meta-analysis of published studies.

METHODS

Relevant publications were identified by a systematic literature search on PubMed and Google Scholar from inception to September 07, 2021. Studies were divided into two groups based on the sepsis criteria applied, namely sepsis-2 or sepsis-3.

RESULTS

Ten studies including 9,475 individuals, of whom 1,370 with sepsis (742 according Sepsis-2 and 628 according to Sepsis-3), met the inclusion criteria for our meta-analysis. The pooled sensitivity and specificity were 0.789 and 0.777 for Sepsis-2 criteria, 0.838 and 0.704 for Sepsis-3 criteria.

CONCLUSIONS

MDW represents a reliable biomarker for sepsis screening.

Translation of Pharmacodynamic Biomarkers of Antibiotic Efficacy in Specific Populations to Optimize Doses

Antibiotic efficacy determination in clinical trials often relies on non-inferiority designs because they afford smaller study sample sizes. These efficacy studies tend to exclude patients within specific populations or include too few patients to discern potential differences in their clinical outcomes. As a result, dosing guidance in patients with abnormal liver and kidney function, age across the lifespan, and other specific populations relies on drug exposure-matching. The underlying assumption for exposure-matching is that the disease course and the response to the antibiotic are similar in patients with and without the specific condition. While this may not be the case, clinical efficacy studies are underpowered to ensure this is true. The current paper provides an integrative review of the current approach to dose selection in specific populations. We review existing clinical trial endpoints that could be measured on a more continuous rather than a discrete scale to better inform exposure-response relationships. The inclusion of newer systemic biomarkers of efficacy can help overcome the current limitations. We use a modeling and simulation exercise to illustrate how an efficacy biomarker can inform dose selection better. Studies that inform response-matching rather than exposure-matching only are needed to improve dose selection in specific populations.

The Value of a Complete Blood Count (CBC) for Sepsis Diagnosis and Prognosis

Sepsis represents an important global health burden due to its high mortality and morbidity. The rapid detection of sepsis is crucial in order to prevent adverse outcomes and reduce mortality. However, the diagnosis of sepsis is still challenging and many efforts have been made to identify reliable biomarkers. Unfortunately, many investigated biomarkers have several limitations that do not support their introduction in clinical practice, such as moderate diagnostic and prognostic accuracy, long turn-around time, and high-costs. Complete blood count represents instead a precious test that provides a wealth of information on individual health status. It can guide clinicians to early-identify patients at high risk of developing sepsis and to predict adverse outcomes. It has several advantages, being cheap, easy-to-perform, and available in all wards, from the emergency department to the intensive care unit. Noteworthy, it represents a first-level test and an alteration of its parameters must always be considered within the clinical context, and the eventual suspect of sepsis must be confirmed by more specific investigations. In this review, we describe the usefulness of basic and new complete blood count parameters as diagnostic and prognostic biomarkers of sepsis.