Cytokines as Potential Biomarkers for Differential Diagnosis of Sepsis and Other Non-Septic Disease Conditions

Association between RANTES/CCL5 levels with Plasmodium infections and malaria severity: a systematic review

BACKGROUND

Malaria continues to be a significant global health concern, and developing effective therapeutic strategies requires an understanding of the immune response to the disease. This systematic review synthesized the current body of research on the role of regulated on activation, normal T cell expressed and secreted (RANTES)-in the pathogenesis and disease severity of malaria.

METHODS

A systematic review protocol was registered with PROSPERO under the registration number CRD42024535822. The systematic review was conducted following PRISMA guidelines to identify studies examining RANTES levels in individuals infected with Plasmodium species. Searches were performed across multiple databases, including ProQuest, Journals@Ovid, Embase, Scopus, PubMed, and MEDLINE. Further searches were performed in Google Scholar. Quality assessment was done using the Joanna Briggs Institute (JBI) critical appraisal tools. Alterations in RANTES levels in patients with malaria were synthesized narratively.

RESULTS

A comprehensive search of major databases identified 22 studies meeting inclusion criteria, predominantly focusing on Plasmodium falciparum and Plasmodium vivax infections. RANTES levels were found to vary significantly across different severities of malaria, with several studies reporting lower levels in severe cases compared to non-malarial controls. However, inconsistencies were observed in the alterations of RANTES levels between severe and non-severe malaria cases.

CONCLUSION

Taken together, the finding of this systematic review underscore the complex regulation of RANTES in malaria pathophysiology. Future research should focus on longitudinal assessments to elucidate the dynamic role of RANTES throughout the course of malaria and recovery, to potentially inform the design of novel therapeutic strategies.

Group 2 innate lymphocytes protect the balance between autophagy and apoptosis in cardiomyocytes during sepsis-induced cardiac injury

Group 2 innate lymphocytes (ILC2) have an important role in orchestrating sepsis-induced immune response. However, the impact of LC2 on sepsis-induced cardiac injury is still not fully understood. This study investigated the mechanisms governing ILC2 activation within the cardiac tissue after sepsis. In vivo experiments using wild-type and IL-33 deficient mice indicated that the presence of interleukin (IL)-33, which participates in expanding and activating ILC2 cells, was correlated with higher ILC2 levels (246 ± 34 vs. 66 ± 18, p < 0.01), reduced cardiac dysfunction, and lower markers of cardiac injury. Conversely, IL-33 deficiency led to exacerbated cardiac damage. Additionally, heart ILC2 significantly increased the expression and secretion of IL-5 (2.18 ± 0.34 ng/ml vs. 1.18 ± 0.24 ng/ml, p < 0.05) and IL-13 (10.55 ± 1.13 ng/ml vs. 7.59 ± 1.13 ng/ml, p < 0.05) following sepsis, with this response being mediated by IL-33. Moreover, IL-5 deficient mice exhibited increased cardiac dysfunction and myocardial apoptosis post-sepsis (20.7 ± 4.28% vs. 29.61 ± 4.28%, p < 0.05). Furthermore, in vitro experiments involving co-cultures of ILC2 with mice cardiomyocytes after lipopolysaccharide (LPS) administration suggested that IL-5 derived from ILC2 protects cardiomyocytes from autophagy and apoptosis. These findings imply that IL-33, released in response to sepsis, induces ILC2 activation and IL-5 secretion, orchestrating the equilibrium between autophagy and apoptosis in cardiomyocytes and offering potential therapeutic avenues for mitigating sepsis-induced cardiac injury.

Calcineurin-NFAT signaling controls neutrophils' ability of chemoattraction upon fungal infection

Calcineurin-nuclear factor of activated T cells (CN-NFAT) inhibitors are widely clinically used drugs for immunosuppression, but besides their required T cell response inhibition, they also undesirably affect innate immune cells. Disruption of innate immune cell function can explain the observed susceptibility of CN-NFAT inhibitor-treated patients to opportunistic fungal infections. Neutrophils play an essential role in innate immunity as a defense against pathogens; however, the effect of CN-NFAT inhibitors on neutrophil function was poorly described. Thus, we tested the response of human neutrophils to opportunistic fungal pathogens, namely Candida albicans and Aspergillus fumigatus, in the presence of CN-NFAT inhibitors. Here, we report that the NFAT pathway members were expressed in neutrophils and mediated part of the neutrophil response to pathogens. Upon pathogen exposure, neutrophils underwent profound transcriptomic changes with subsequent production of effector molecules. Importantly, genes and proteins involved in the regulation of the immune response and chemotaxis, including the chemokines CCL2, CCL3, and CCL4 were significantly upregulated. The presence of CN-NFAT inhibitors attenuated the expression of these chemokines and impaired the ability of neutrophils to chemoattract other immune cells. Our results amend knowledge about the impact of CN-NFAT inhibition in human neutrophils.

CCL4 as a potential serum factor in differential diagnosis of central nervous system inflammatory diseases and gliomas

Computed tomography (CT) scans and magnetic resonance imaging (MRI) are commonly utilized to detect brain gliomas and central nervous system inflammation diseases. However, there are instances where depending solely on medical imaging for a precise diagnosis may result in unsuitable medications or treatments. Pathological analysis is regarded as the definitive method for diagnosing brain gliomas or central nervous system inflammation diseases. To achieve this, a craniotomy or stereotaxic biopsy is necessary to collect brain tissue, which can lead to complications such as cerebral hemorrhage, neurological deficits, cerebrospinal fluid leaks, and cerebral edema. Consequently, the advancement of non-invasive or minimally invasive diagnostic techniques is currently a high priority. This study included samples from four glioma patients and five patients with central nervous system inflammatory diseases, comprising both serum and paired cerebrospinal fluid (CSF). A total of 40 human cytokines were identified in these samples. We utilized a receiver operating characteristic (ROC) analysis to assess the sensitivity and specificity for distinguishing central nervous system inflammation diseases and gliomas. Additionally, we examined the correlation of these factors between serum and CSF in the patients. Ultimately, the identified factors were validated using serum from patients with clinically confirmed gliomas and central nervous system inflammation diseases followed by detection and statistical analysis through ELISA. The levels of serum factors IL-4, IFN-α, IFN-γ, IL-6, TNF-α, CCL4, CCL11, and VEGF were found to be significantly higher in gliomas compared with inflammatory diseases of the central nervous system (p < 0.05). Furthermore, a strong correlation was observed between the levels of CCL4 in serum and CSF, with a correlation coefficient of r = 0.92 (95% CI = 0.20-0.99, p = 0.027). We gathered more clinical samples to provide further validation of the abundance of CCL4 expression. A clinical study analyzing serum samples from 19 glioma patients and 22 patients with central nervous system inflammation diseases revealed that CCL4 levels were notably elevated in the inflammatory group compared with the glioma group (p < 0.001). These results suggest that assessing serum CCL4 levels may be useful in distinguishing those patients for clinical diagnostic purposes.

Differential expression of plasma cytokines in sepsis patients and their clinical implications

BACKGROUND

Sepsis, which is characterized by acute systemic inflammation and is associated with high rates of morbidity and mortality, presents a significant challenge in health care. Some scholars have found that the sequential organ failure assessment (SOFA) and quick SOFA scores are not ideal for predicting severe sepsis and mortality. Microbial culture takes a long time (2-3 d) and provides no information for early diagnosis and treatment. Therefore, new diagnostic methods for sepsis need to be explored.

AIM

To assess cytokine levels in the plasma of sepsis patients and identify potential biomarkers for diagnosing sepsis.

METHODS

Ten sepsis patients admitted to the emergency department within 24 h of onset were enrolled as the observation group, whereas ten noninfected patients served as the control group. Of the 10 noninfected patients, 9 hypertension combined with cerebral infarction, 1 patients with vertiginous syndrome. Plasma Cytokines were measured using the Bio-Plex Pro™ Human Chemokine Panel 40-plex. Differentially expressed cytokines in plasma of sepsis and nonsepsis patients were analyzed using Gene Ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses.

RESULTS

Interleukin (IL)-16, granulocyte-macrophage granulocyte-macrophage colony-stimulating factor (GM-CSF), CX3CL1, CXCL9, CXCL16, CCL25, and CCL23 plasma levels were significantly increased in sepsis patients. GO analysis revealed that these cytokines were mainly associated with cellular structures such as intermediates, nuclear plaques, adhesion plaques, lateral plasma membranes, and cell matrix junctions. These genes were involved in various molecular functions, such as cytokine activity, receptor ligand activity, and signal receptor activator activity, contributing to various biological functions, such as leukocyte chemotaxis, migration, and chemotaxis. KEGG analysis indicated involvement in cytokine cytokine receptor interactions, chemokine signaling pathways, virus-protein interactions with cytokines and cytokine receptors, and the tumor necrosis factor signaling pathway.

CONCLUSION

Elevated serum levels of IL-16, GM-CSF, CX3CL1, CXCL9, CXCL16, CCL25, and CCL23 in sepsis patients suggest their potential as diagnostic biomarkers for sepsis.

Molecular mechanisms of Sepsis attacking the immune system and solid organs

Remarkable progress has been achieved in sepsis treatment in recent times, the mortality rate of sepsis has experienced a gradual decline as a result of the prompt administration of antibiotics, fluid resuscitation, and the implementation of various therapies aimed at supporting multiple organ functions. However, there is still significant mortality and room for improvement. The mortality rate for septic patients, 22.5%, is still unacceptably high, accounting for 19.7% of all global deaths. Therefore, it is crucial to thoroughly comprehend the pathogenesis of sepsis in order to enhance clinical diagnosis and treatment methods. Here, we summarized classic mechanisms of sepsis progression, activation of signal pathways, mitochondrial quality control, imbalance of pro-and anti- inflammation response, diseminated intravascular coagulation (DIC), cell death, presented the latest research findings for each mechanism and identify potential therapeutic targets within each mechanism.

Optical Aptamer-Based Cytokine Nanosensor Detects Macrophage Activation by Bacterial Toxins

Overactive or dysregulated cytokine expression is a hallmark of many acute and chronic inflammatory diseases. This is true for acute or chronic infections, neurodegenerative diseases, autoimmune diseases, cardiovascular diseases, cancer, and others. Cytokines such as interleukin-6 (IL-6) are known therapeutic targets and biomarkers for such inflammatory diseases. Platforms for cytokine detection are, therefore, desirable tools for both research and clinical applications. Single-walled carbon nanotubes (SWCNT) are versatile nanomaterials with near-infrared fluorescence that can serve as transducers for optical sensors. When functionalized with an analyte-specific recognition element, SWCNT emission may become sensitive and selective toward the desired target. SWCNT-aptamer sensors are easily assembled, inexpensive, and biocompatible. In this work, we introduced a nanosensor design based on SWCNT and a DNA aptamer specific to IL-6. We first evaluated several SWCNT-aptamer constructs based on this simple direct complexation method, wherein the aptamer both solubilizes the SWCNT and confers sensitivity to IL-6. The sensor limit of detection, 105 ng/mL, lies in the relevant range for pathological IL-6 levels. Upon investigation of sensor kinetics, we found rapid response within seconds of antigen addition which continued over the course of 3 h. We found that this sensor construct is stable and the aptamer is not displaced from the nanotube surface during IL-6 detection. Finally, we investigated the ability of this sensor construct to detect macrophage activation caused by bacterial lipopolysaccharides (LPS) in an in vitro model of disease, finding rapid and sensitive detection of macrophage-expressed IL-6. We are confident that further development of this sensor will have novel implications for diagnosis of acute and chronic inflammatory diseases, in addition to contributing to the understanding of the role of cytokines in these diseases.

Acute lung injury is prevented by monocyte locomotion inhibitory factor in an experimental severe malaria mouse model

Acute lung injury caused by severe malaria (SM) is triggered by a dysregulated immune response towards the infection with Plasmodium parasites. Postmortem analysis of human lungs shows diffuse alveolar damage (DAD), the presence of CD8 lymphocytes, neutrophils, and increased expression of Intercellular Adhesion Molecule 1 (ICAM-1). P. berghei ANKA (PbA) infection in C57BL/6 mice reproduces many SM features, including acute lung injury characterized by DAD, CD8+ T lymphocytes and neutrophils in the lung parenchyma, and tissular expression of proinflammatory cytokines and adhesion molecules, such as IFNγ, TNFα, ICAM, and VCAM. Since this is related to a dysregulated immune response, immunomodulatory agents are proposed to reduce the complications of SM. The monocyte locomotion inhibitory factor (MLIF) is an immunomodulatory pentapeptide isolated from axenic cultures of Entamoeba hystolitica. Thus, we evaluated if the MLIF intraperitoneal (i.p.) treatment prevented SM-induced acute lung injury. The peptide prevented SM without a parasiticidal effect, indicating that its protective effect was related to modifications in the immune response. Furthermore, peripheral CD8+ leukocytes and neutrophil proportions were higher in infected treated mice. However, the treatment prevented DAD, CD8+ cell infiltration into the pulmonary tissue and downregulated IFNγ. Moreover, VCAM-1 expression was abrogated. These results indicate that the MLIF treatment downregulated adhesion molecule expression, impeding cell migration and proinflammatory cytokine tissular production, preventing acute lung injury induced by SM. Our findings represent a potential novel strategy to avoid this complication in various events where a dysregulated immune response triggers lung injury.

Vibrio cholerae Bacteremia: An Enigma in Cholera-Endemic African Countries

Cholera is highly endemic in many sub-Saharan African countries. The bacterium Vibrio cholerae is responsible for this severe dehydrating diarrheal disease that accounts for over 100,000 deaths each year globally. In recent years, the pathogen has been found to invade intestinal layers and translocate into the bloodstream of humans. The non-toxigenic strains of V. cholerae (non-O1/O139), also known as NOVC, which do not cause epidemic or pandemic cases of cholera, are the major culprits of V. cholerae bacteremia. In non-cholera-endemic regions, clinical reports on NOVC infection have been noted over the past few decades, particularly in Europe and America. Although low-middle-income countries are most susceptible to cholera infections because of challenges with access to clean water and inappropriate sanitation issues, just a few cases of V. cholerae bloodstream infections have been reported. The lack of evidence-based research and surveillance of V. cholerae bacteremia in Africa may have significant clinical implications. This commentary summarizes the existing knowledge on the host risk factors, pathogenesis, and diagnostics of NOVC bacteremia.

An optical aptamer-based cytokine nanosensor detects macrophage activation by bacterial toxins

Overactive or dysregulated cytokine expression is hallmark of many acute and chronic inflammatory diseases. This is true for acute or chronic infection, neurodegenerative diseases, autoimmune diseases, cardiovascular disease, cancer, and others. Cytokines such as interleukin-6 (IL-6) are known therapeutic targets and biomarkers for such inflammatory diseases. Platforms for cytokine detection are therefore desirable tools for both research and clinical applications. Single-walled carbon nanotubes (SWCNT) are versatile nanomaterials with near-infrared fluorescence that can serve as transducers for optical sensors. When functionalized with an analyte-specific recognition element, SWCNT emission may become sensitive and selective towards the desired target. SWCNT-aptamer sensors are easily assembled, inexpensive, and biocompatible. In this work, we introduced a nanosensor design based on SWCNT and a DNA aptamer specific to IL-6. We first evaluated several SWCNT-aptamer constructs based on this simple direct complexation method, wherein the aptamer both solubilizes the SWCNT and confers sensitivity to IL-6. The sensor limit of detection, 105 ng/mL, lies in the relevant range for pathological IL-6 levels. Upon investigation of sensor kinetics, we found rapid response within seconds of antigen addition which continued over the course of three hours. We found that this sensor construct is stable, and the aptamer is not displaced from the nanotube surface during IL-6 detection. Finally, we investigated the ability of this sensor construct to detect macrophage activation caused by bacterial lipopolysaccharides (LPS) in an in vitro model of disease, finding rapid and sensitive detection of macrophage-expressed IL-6. We are confident further development of this sensor will have novel implications for diagnosis of acute and chronic inflammatory diseases, in addition to contributing to the understanding of the role of cytokines in these diseases.

Inflammatory markers for improved recurrent UTI diagnosis in postmenopausal women

Recurrent urinary tract infection (rUTI) severely impacts postmenopausal women. The lack of rapid and accurate diagnostic tools is a major obstacle in rUTI management as current gold standard methods have >24-h diagnostic windows. Work in animal models and limited human cohorts have identified robust inflammatory responses activated during UTI. Consequently, urinary inflammatory cytokines secreted during UTI may function as diagnostic biomarkers. This study aimed to identify urinary cytokines that could accurately diagnose UTI in a controlled cohort of postmenopausal women. Women passing study exclusion criteria were classified into no UTI and active rUTI groups, and urinary cytokine levels were measured by immunoassay. Pro-inflammatory cytokines IL-8, IL-18, IL-1β, and monocyte chemoattractant protein-1 were significantly elevated in the active rUTI group, and anti-inflammatory cytokines IL-13 and IL-4 were elevated in women without UTI. We evaluated cytokine diagnostic performance and found that an IL-8, prostaglandin E2, and IL-13 multivariable model had the lowest misclassification rate and highest sensitivity. Our data identify urinary IL-8, prostaglandin E2, and IL-13 as candidate biomarkers that may be useful in the development of immunoassay-based UTI diagnostics.

Pediatric sepsis inflammatory blood biomarkers that correlate with clinical variables and severity of illness scores

BACKGROUND

Sepsis is a dysregulated systemic inflammatory response triggered by infection, resulting in organ dysfunction. A major challenge in clinical pediatrics is to identify sepsis early and then quickly intervene to reduce morbidity and mortality. As blood biomarkers hold promise as early sepsis diagnostic tools, we aimed to measure a large number of blood inflammatory biomarkers from pediatric sepsis patients to determine their predictive ability, as well as their correlations with clinical variables and illness severity scores.

METHODS

Pediatric patients that met sepsis criteria were enrolled, and clinical data and blood samples were collected. Fifty-eight inflammatory plasma biomarker concentrations were determined using immunoassays. The data were analyzed with both conventional statistics and machine learning.

RESULTS

Twenty sepsis patients were enrolled (median age 13 years), with infectious pathogens identified in 75%. Vasopressors were administered to 85% of patients, while 55% received invasive ventilation and 20% were ventilated non-invasively. A total of 24 inflammatory biomarkers were significantly different between sepsis patients and age/sex-matched healthy controls. Nine biomarkers (IL-6, IL-8, MCP-1, M-CSF, IL-1RA, hyaluronan, HSP70, MMP3, and MMP10) yielded AUC parameters > 0.9 (95% CIs: 0.837-1.000; p < 0.001). Boruta feature reduction yielded 6 critical biomarkers with their relative importance: IL-8 (12.2%), MCP-1 (11.6%), HSP70 (11.6%), hyaluronan (11.5%), M-CSF (11.5%), and IL-6 (11.5%); combinations of 2 biomarkers yielded AUC values of 1.00 (95% CI: 1.00-1.00; p < 0.001). Specific biomarkers strongly correlated with illness severity scoring, as well as other clinical variables. IL-3 specifically distinguished bacterial versus viral infection (p < 0.005).

CONCLUSIONS

Specific inflammatory biomarkers were identified as markers of pediatric sepsis and strongly correlated to both clinical variables and sepsis severity.

Navigating the Cytokine Storm: A Comprehensive Review of Chemokines and Cytokines in Sepsis

This comprehensive review thoroughly explores the intricate relationship between chemokines, cytokines, and the cytokine storm in sepsis, offering a nuanced understanding of the molecular mechanisms underpinning this life-threatening syndrome. Beginning with examining sepsis stages and immune response dynamics, the review emphasizes the dysregulation leading to the cytokine storm, where pro- and anti-inflammatory cytokines disrupt the delicate immune equilibrium. Delving into chemokines, the discussion encompasses subfamilies, receptors, and functions, highlighting their critical roles in immune cell migration and activation during sepsis. The implications for clinical practice are substantial, suggesting avenues for targeted diagnostics and therapeutic interventions. The review identifies areas for future research, including the search for novel biomarkers, deeper insights into cytokine regulation, and the pursuit of personalized medicine approaches. This comprehensive exploration aims to guide clinicians, researchers, and policymakers in navigating the complexities of sepsis, fostering a foundation for transformative advancements in understanding and managing this formidable clinical challenge.

Immune-Related Molecules CD3G and FERMT3: Novel Biomarkers Associated with Sepsis

Sepsis ranks among the most common health problems worldwide, characterized by organ dysfunction resulting from infection. Excessive inflammatory responses, cytokine storms, and immune-induced microthrombosis are pivotal factors influencing the progression of sepsis. Our objective was to identify novel immune-related hub genes for sepsis through bioinformatic analysis, subsequently validating their specificity and potential as diagnostic and prognostic biomarkers in an animal experiment involving a sepsis mice model. Gene expression profiles of healthy controls and patients with sepsis were obtained from the Gene Expression Omnibus (GEO) and analysis of differentially expressed genes (DEGs) was conducted. Subsequently, weighted gene co-expression network analysis (WGCNA) was used to analyze genes within crucial modules. The functional annotated DEGs which related to the immune signal pathways were used for constructing protein-protein interaction (PPI) analysis. Following this, two hub genes, FERMT3 and CD3G, were identified through correlation analyses associated with sequential organ failure assessment (SOFA) scores. These two hub genes were associated with cell adhesion, migration, thrombosis, and T-cell activation. Furthermore, immune infiltration analysis was conducted to investigate the inflammation microenvironment influenced by the hub genes. The efficacy and specificity of the two hub genes were validated through a mice sepsis model study. Concurrently, we observed a significant negative correlation between the expression of CD3G and IL-1β and GRO/KC. These findings suggest that these two genes probably play important roles in the pathogenesis and progression of sepsis, presenting the potential to serve as more stable biomarkers for sepsis diagnosis and prognosis, deserving further study.

Different PfEMP1-expressing Plasmodium falciparum variants induce divergent endothelial transcriptional responses during co-culture

The human malaria parasite Plasmodium falciparum is responsible for the majority of mortality and morbidity caused by malaria infection and differs from other human malaria species in the degree of accumulation of parasite-infected red blood cells in the microvasculature, known as cytoadherence or sequestration. In P. falciparum, cytoadherence is mediated by a protein called PfEMP1 which, due to its exposure to the host immune system, undergoes antigenic variation resulting in the expression of different PfEMP1 variants on the infected erythrocyte membrane. These PfEMP1s contain various combinations of adhesive domains, which allow for the differential engagement of a repertoire of endothelial receptors on the host microvasculature, with specific receptor usage associated with severe disease. We used a co-culture model of cytoadherence incubating human brain microvascular endothelial cells with erythrocytes infected with two parasite lines expressing different PfEMP1s that demonstrate different binding profiles to vascular endothelium. We determined the transcriptional profile of human brain microvascular endothelial cells (HBMEC) following different incubation periods with infected erythrocytes, identifying different transcriptional profiles of pathways previously found to be involved in the pathology of severe malaria, such as inflammation, apoptosis and barrier integrity, induced by the two PfEMP1 variants.

Causal association of circulating cytokines with sepsis: a Mendelian randomization study

Background

Observational studies have reported an association between circulating cytokines and sepsis. However, the precise causal relationship between these factors remains unclear. The objective of this study was to explore the causal link between circulating cytokines and sepsis using genetic data within the framework of Mendelian Randomization (MR).

Methods

We performed a two-sample MR analysis to investigate this causality relationship in individuals of European ancestry. The publicly available genome-wide association studies (GWAS) statistics were used. We selected eligible instrumental single nucleotide polymorphisms (SNPs) that were significantly related to the circulating cytokines. Multiple MR analysis approaches were carried out, which included inverse variance weighted (IVW), Weighted Median, MR-Egger, Weighted Mode, Simple Mode, and MR pleiotropy residual sum and outlier (MR-PRESSO) methods.

Results

We found evidence to support the causal role of genetically predicted circulating levels on decreased risk of sepsis, including RANTES (OR = 0.920, 95% CI: 0.849-0.997, P = 0.041) and basic fibroblast growth factor (basic-FGF) (OR = 0.869, 95% CI: 0.766-0.986, P = 0.029). Additionally, MR analysis positive causal association of between beta-nerve growth factor (β-NGF) and sepsis (OR = 1.120, 95% CI: 1.037-1.211, P = 0.004). The results of MR-Egger, Weighted Median, Weighted Mode, and Simple Mode methods were consistent with the IVW estimates. Sensitivity analysis showed no horizontal pleiotropy to bias the causal estimates.

Conclusion

This MR study provides first novel evidence that genetically predicted causal association of circulating levels of RANTES, basic-FGF, and β-NGF with altered sepsis risk. The findings shed light on the potential involvement of these cytokines in sepsis pathogenesis. Although requiring additional confirmation, the results contribute new insights into cytokine mediators in sepsis and suggest promising future research directions.

Advances in the Study of Immunosuppressive Mechanisms in Sepsis

Sepsis is a life-threatening disease caused by a systemic infection that triggers a dysregulated immune response. Sepsis is an important cause of death in intensive care units (ICUs), poses a major threat to human health, and is a common cause of death in ICUs worldwide. The pathogenesis of sepsis is intricate and involves a complex interplay of pro- and anti-inflammatory mechanisms that can lead to excessive inflammation, immunosuppression, and potentially long-term immune disorders. Recent evidence highlights the importance of immunosuppression in sepsis. Immunosuppression is recognized as a predisposing factor for increased susceptibility to secondary infections and mortality in patients. Immunosuppression due to sepsis increases a patient's chance of re-infection and increases organ load. In addition, antibiotics, fluid resuscitation, and organ support therapy have limited impact on the prognosis of septic patients. Therapeutic approaches by suppressing excessive inflammation have not achieved the desired results in clinical trials. Research into immunosuppression has brought new hope for the treatment of sepsis, and a number of therapeutic approaches have demonstrated the potential of immunostimulatory therapies. In this article, we will focus on the mechanisms of immunosuppression and markers of immune monitoring in sepsis and describe various targets for immunostimulatory therapy in sepsis.

Interleukin-5 levels in relation to malaria severity: a systematic review

BACKGROUND

The role of cytokines such as interleukin-5 (IL-5) in the pathogenesis of malaria remains unclear. This systematic review sought to synthesize variations in IL-5 levels between severe and uncomplicated malaria, as well as between malaria and controls not afflicted with the disease.

METHODS

This systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022368773). Searches for studies that reported IL-5 levels in patients with malaria (any severity) and/or uninfected individuals were performed in Web of Science, PubMed, EMBASE, Scopus, CENTRAL, and MEDLINE, between 1st and 10th October, 2022. The risk of bias among all included studies was minimized using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for reporting observational studies. The differences in IL-5 levels between malaria and uninfected controls, and between severe and uncomplicated malaria were synthesized by narrative synthesis.

RESULTS

Among 1177 articles identified in the databases, 23 matched the eligibility criteria and were included in this systematic review. Qualitative syntheses showed the heterogeneity of IL-5 levels between different severities of clinical malaria and uninfected controls. The majority of the included studies (12/15 studies, 80%) found no change in IL-5 levels between malaria cases and uninfected controls. Similarly, most studies found no difference in IL-5 levels between severe (regardless of complications) and uncomplicated malaria (4/8 studies, 50%). The qualitative syntheses revealed that most studies found no difference in IL-5 levels between severe and non-severe malaria.

CONCLUSIONS

The comprehensive review suggests that IL-5 levels are unchanged in patients with different levels of clinical severity of malaria and uninfected controls. Given the limited number of published studies on IL-5 levels in malaria, there is a need for additional research to determine the function of this cytokine in the pathogenesis of malaria.

Inflammatory cytokines as potential biomarkers for early diagnosis of severe malaria in children in Ghana

BACKGROUND

Severe malaria (SM) is a fatal multi-system disease which accounted for an estimated 619,000 deaths in 2021. Less than 30% of children presenting with SM are diagnosed and treated promptly, resulting in increased mortality and neurologic impairments in survivors. Studies have identified cytokine profiles that differentiate the various clinical manifestations of malaria (severe and uncomplicated). However, the diagnostic capability of these cytokines in differentiating between the disease states in terms of cut-off values has not yet been determined.

METHODS

The plasma levels of 22 pro-inflammatory cytokines (Eotaxin/CCL 11, interferon-gamma (IFN-γ), interleukin (IL)- 2, IL-6, IL-1β, IL-12p40/p70, IL-17A, RANTES, MCP-1, IL-15, IL-5, IL-1RA, IL-2R, IFN-α, IP-10, TNF, MIG, MIP-1α, MIP-1β, IL-7, IL-8 and Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF), and 3 anti-inflammatory cytokines-(IL-4, IL-13 and IL-10) in patients with SM, uncomplicated malaria (UM) and other febrile conditions, were measured and compared using the Human Cytokine Magnetic 25-Plex Panel. The receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of these cytokines.

RESULTS

The level of the pro-inflammatory cytokine, IL-17A, was significantly higher in the SM group as compared to the UM group. Levels of the anti-inflammatory cytokines however did not differ significantly among the SM and UM groups. Only IL-1β and IL-17A showed good diagnostic potential after ROC curve analysis.

CONCLUSION

The data show that levels of pro-inflammatory cytokines correlate with malaria disease severity. IL-1β and IL-17A showed good diagnostic potentials and can be considered for use in clinical practice to target treatment.

Effects of adenosine N1-Oxide and pioglitazone on inflammatory and antioxidant state in sepsis caused by experimental cecal puncture in rat

Sepsis is an acute condition caused by the systemic inflammatory response syndrome to an infection. There are very few drugs that could improve the severe conditions in patients with sepsis. Hence, it is important to consider different treatment options. In this survey, we studied the effect of adenosine N1-oxide (ANO) and pioglitazone on rats with cecal ligation and perforation (CLP). They were randomly divided to four groups (n = 10) including Group A: as control group receiving normal saline, Group B: the rats with CLP as surgical control group, Group C: the rats receiving ANO, and Group D: the rats receiving pioglitazone. Interleukin (IL) -6, IL-1β, tumor necrosis factor alpha (TNF-α), nitric-oxide (NO) in serum blood and superoxide dismutase (SOD), catalase (CAT) malondialdehyde, (MDA) and myeloperoxidase (MPO) in liver and spleen homogenates were measured. The amount of antioxidant enzymes in the spleen and liver, and finally cell viability and rats' survival were investigated. The measurement of blood serum nitric-oxide and survival of all groups of rats were also performed. The results indicated that both drugs could cause a decrease in IL-1β, IL-6, TNF-α and NO in rat blood serum and MDA and MPO in the liver and spleen homogenates, however, a significant increase in SOD and CAT in the liver and spleen homogenates in rats that received ANO and pioglitazone was observed compared to rats with CLP group. Cell viability and rats' survival were significantly improved in rats that received ANO and pioglitazone compared to rats with CLP group. Adenosine N1-oxide showed stronger and more effective effects.

Xanthohumol ameliorates cardiac injury induced by sepsis in a mice model: role of toll-like receptor 4

Sepsis, a life-threatening condition arising from infection, often results in multi-organ failure, including cardiac dysfunction. This study investigated Xanthohumol, a natural compound, and its potential mechanism of action to enhance heart function following sepsis. A total of twenty-four adult male Swiss albino mice were allocated randomly to one of four equal groups (n=6): sham, CLP, vehicle Xanthohumol the same amount of DMSO injected IP 10 minutes before the CLP, and Xanthohumol group (0.4 mg/kg of Xanthohumol administered IP before the CLP process). Toll-like receptor 4, pro-inflammatory mediators, anti-inflammatory markers, oxidative stress indicators, apoptosis markers, and serum cardiac damage biomarkers were measured in the cardiac tissue using ELISA. Data with normal distribution were analyzed using t-test and ANOVA tests (p<0.05). In comparison to the sham group, the sepsis group had significantly higher levels of TLR-4, IL-6, TNF-α, MIF, F2-isoprostane, caspase-3, cTn-I, and CK-MB, while the pre-treated group with Xanthohumol had significantly lower levels (p<0.05) of these markers than the sepsis group. Bcl-2 showed no significant difference in Xanthohumol pre-treated group relative to the sepsis group, while IL-10 was significantly elevated. Xanthohumol dramatically reduced cardiac tissue injury (p<0.05) relative to the CLP group. By blocking the downstream signal transduction pathways of TLR-4 and NF-kB, Xanthohumol was shown to lessen cardiac damage in male mice during CLP-induced polymicrobial sepsis.

Evaluation of Biomarkers from Peritoneal Fluid as Predictors of Severity for Abdominal Sepsis Patients Following Emergency Laparotomy

Purpose

Intra-abdominal infection is considered the second most common cause of sepsis and results in localized or diffused inflammation of the peritoneum. The main treatment for abdominal sepsis is an emergency laparotomy for source control. However, surgical trauma also causes inflammation, and patients become susceptible to postoperative complications. Therefore, it is necessary to identify biomarkers that can be used to distinguish sepsis from abdominal infection. This prospective study investigated whether cytokine levels in the peritoneum could predict complications and indicate severity of sepsis following emergency laparotomy.

Methods

We prospectively observed 97 patients with abdominal infection admitted to the Intensive Care Unit (ICU). After emergency laparotomy,SEPSIS-3 criteria were used for the diagnosis of sepsis or septic shock. Blood and peritoneal fluid samples were drawn at postoperative admission to the ICU and cytokine concentrations were measured by flow cytometry.

Results

Fifty-eight postoperative patients were enrolled. We found significant elevations in the peritoneal concentrations of IL-1β, IL-6, TNF-α, IL-17, and IL-2 in patients with sepsis or septic shock compared to the patients without sepsis after surgery. Positive correlations between levels of these peritoneal cytokines with APACHE II scores were found: IL-6, in particular, had the highest correlation coefficient of 0.833. Meanwhile, IL-10 in blood, MCP-1 and IL-8 in both blood and peritoneum were simultaneously increased in patients with sepsis and septic shock, and also positively correlated with disease severity.

Conclusion

The cytokine storm that occurs in the abdominal cavity after emergency laparotomy may be the main mechanism leading to sepsis. It may be valuable to measure IL-1β, IL-6, TNF-α,IL-17, IL-2, MCP-1, and IL-8 in the peritoneal fluid, combined with serum IL-10, MCP-1 and IL-8, in a panel of cytokines, to assess the severity of sepsis and predict mortality from abdominal infection after emergency laparotomy.

The Use of Host Biomarkers for the Management of Invasive Fungal Disease

Invasive fungal disease (IFD) causes severe morbidity and mortality, and the number of IFD cases is increasing. Exposure to opportunistic fungal pathogens is inevitable, but not all patients with underlying diseases increasing susceptibility to IFD, develop it. IFD diagnosis currently uses fungal biomarkers and clinical risk/presentation to stratify high-risk patients and classifies them into possible, probable, and proven IFD. However, the fungal species responsible for IFD are highly diverse and present numerous diagnostic challenges, which culminates in the empirical anti-fungal treatment of patients at risk of IFD. Recent studies have focussed on host-derived biomarkers that may mediate IFD risk and can be used to predict, and even identify IFD. The identification of novel host genetic variants, host gene expression changes, and host protein expression (cytokines and chemokines) associated with increased risk of IFD has enhanced our understanding of why only some patients at risk of IFD actually develop disease. Furthermore, these host biomarkers when incorporated into predictive models alongside conventional diagnostic techniques enhance predictive and diagnostic results. Once validated in larger studies, host biomarkers associated with IFD may optimize the clinical management of populations at risk of IFD. This review will summarise the latest developments in the identification of host biomarkers for IFD, their use in predictive modelling and their potential application/usefulness for informing clinical decisions.