IL-1β/IL-6/CRP and IL-18/ferritin: Distinct Inflammatory Programs in Infections

Ultrasensitive Electrochemical Vertical Flow Immunoassay for Rapid and Simultaneous Detection of Interleukin-6 and Procalcitonin

Rapid and multiplexed detection of biomarkers plays an indispensable role in disease diagnosis. Although paper-based lateral flow immunoassays have been widely used in this field, the speediness and throughput are still challenging issues. Herein, an electrochemical vertical flow immunoassay device (eVFID) is fabricated for rapid, ultrasensitive, and multiplexed detection of inflammatory biomarkers. Working electrodes with excellent electrochemical performance and permeability properties were directly fabricated on the nitrocellulose membrane to enable both the vertical flow of the sample solution and electrochemical detection. This vertical configuration can remarkably improve the speediness of the immunoassay and effectively inhibit the cross-talk reactions among immunomolecules, thus allowing rapid and simultaneous detection of multiplexed biomarkers. Furthermore, a signal amplification strategy based on horseradish peroxidase and tetramethylbenzidine was integrated into the eVFID to substantially increase the sensitivity of the electrochemical detection. A low limit of detection of 0.1 and 0.22 pg mL-1 was obtained for two low-abundance inflammatory biomarkers, interleukin-6 (IL-6) and procalcitonin (PCT), respectively. Finally, using a two-channel eVFID, simultaneous detection of IL-6 and PCT in human plasma samples was successfully realized within 5 min. We believe that the eVFID holds great promise for speedy and high-throughput biomarker detection at the point of care.

Blood Inflammatory Markers and Cytokines in COVID-19 Patients With Bacterial Coinfections

BACKGROUND

Bacterial coinfection in patients with SARS-CoV-2 infection is an important risk factor for death. This study investigated whether there were differences in levels of serum inflammatory markers in COVID-19 patients with bacterial coinfections compared with those without bacterial infection.

METHODS

A total of 235 inpatients with SARS-CoV-2 infection admitted to Qingdao Central Hospital from December 7, 2022, to August 7, 2024, were included. Patients were divided into a bacteria-positive group (115 cases) and a bacteria-negative group (120 cases) according to whether they had bacterial coinfections. PCT, CRP, and 12 kinds of cytokines were compared between groups, and the distribution of bacterial species in the positive group was statistically analyzed.

RESULTS

The serum levels of CRP (Z = 8.94, p < 0.001), PCT (Z = 5.59, p < 0.001), IL-1β (t = 4.863, p < 0.001), IL-2 (t = 5.810, p < 0.001), IL-5 (t = 3.837, p < 0.001), IL-6 (t = 4.910, p < 0.001), IL-8 (t = 3.325, p < 0.001), ILIL-12p70 (t = 4.722, p < 0.001), IL-17 (t = 3.315, p = 0.001) and TNF-α (t = 4.251, p < 0.001) between the two groups were significantly different. IL-4, IL-10, IFN-α, and IFN-γ were not statistically significant (p > 0.05). Among the 115 bacteria-positive patients, 56 patients were positive for one species and 59 patients were multiple infections. Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae were common species.

CONCLUSIONS

Serum PCT and CRP levels in COVID-19 patients with bacterial coinfection are higher than those without bacterial infection. Cytokines such as IL-1β, IL-2, IL-5, IL-6, IL-8, IL-12p70, IL-17, and TNF-α may be involved in the progression of COVID-19 combined with bacterial infection. They can be used as potential markers to evaluate the disease condition and prognosis.

The regulatory role of Epinephelus Coioides miR-21 in the infection and replication of iridovirus SGIV

Iridovirus SGIV is a highly pathogenic virus of fish that can cause more than 90% mortality in Epinephelus coioides, a marine farmed fish in South China. miRNAs can be involved in regulating the development of virus-induced diseases. In this study, SGIV infection could significantly inhibit the expression of E. coioides miR-21. And, overexpressing miR-21 could inhibit the expressions of viral key genes (ICP18, VP19, LITAF and MCP), SGIV-induced CPE, and viral titers. Overexpression of miR-21 promoted the promoter activity of AP-1/NF-κB, SGIV-induced apoptosis, and activities of caspase 3/9. Inhibiting miR-21 could produce the opposite results. E. Coioides PDCD4 is a targeting gene of miR-21, and we speculate that PDCD4 downregulation may, at least in part, explain the observed antiviral effects. These studies indicate that miR-21 could inhibit the infection and replication of SGIV, which might provide a molecular basis for further exploring the mechanism of SGIV invasion.

Identification of a 5-Plex Cytokine Signature that Differentiates Patients with Multiple Systemic Inflammatory Diseases

Patients with non-infectious systemic inflammation may suffer from one of many diseases, including hyperinflammation (HI), autoinflammatory disorders (AID), and systemic autoimmune disease (AI). Despite their clinical overlap, the pathophysiology and patient management differ between these disorders. We aimed to investigate blood biomarkers able to discriminate between patient groups. We included 44 patients with active clinical and/or genetic systemic inflammatory disease (9 HI, 27 AID, 8 systemic AI) and 16 healthy controls. We quantified 55 serum proteins and combined multiple machine learning algorithms to identify five proteins (CCL26, CXCL10, ICAM-1, IL-27, and SAA) that maximally separated patient groups. High ICAM-1 was associated with HI. AID was characterized by an increase in SAA and decrease in CXCL10 levels. A trend for higher CXCL10 and statistically lower SAA was observed in patients with systemic AI. Principal component analysis and unsupervised hierarchical clustering confirmed separation of disease groups. Logistic regression modelling revealed a high statistical significance for HI (P = 0.001), AID, and systemic AI (P < 0.0001). Predictive accuracy was excellent for systemic AI (AUC 0.94) and AID (0.91) and good for HI (0.81). Further research is needed to validate findings in a larger prospective cohort. Results will contribute to a better understanding of the pathophysiology of systemic inflammatory disorders and can improve diagnosis and patient management.

Immune modulation through secretory autophagy

Autophagy is a central mechanism of cellular homeostasis through the degradation of a wide range of cellular constituents. However, recent evidence suggests that autophagy actively provides information to neighboring cells via a process called secretory autophagy. Secretory autophagy couples the autophagy machinery to the secretion of cellular content via extracellular vesicles (EVs). EVs carry a variety of cargo, that reflect the pathophysiological state of the originating cells and have the potential to change the functional profile of recipient cells, to modulate cell biology. The immune system has evolved to maintain local and systemic homeostasis. It is able to sense a wide array of molecules signaling disturbed homeostasis, including EVs and their content. In this review, we explore the emerging concept of secretory autophagy as a means to communicate cellular, and in total tissue pathophysiological states to the immune system to initiate the restoration of tissue homeostasis. Understanding how autophagy mediates the secretion of immunogenic factors may hold great potential for therapeutic intervention.

Interferon gamma-gaillardin nanocomplex formation with improved anti-melanoma effects

This study presents a comprehensive analysis of IFN-γ-Gaillardin nanoparticles (NPs) using a combination of computational, biophysical and cell-based approaches. The molecular docking analysis revealed that both hydrogen and hydrophobic forces are involved in the formation of IFN-γ-Gaillardin complex The interaction between IFN-γ and Gaillardin was further characterized by a pronounced ANS fluorescence spectrum peak and a higher intensity for IFN-γ. The Langmuir, Scatchard, and Hill analyses revealed a higher affinity and lower dissociation constant for IFN-γ NPs compared to IFN-γ alone, suggesting enhanced complex stability. Thermal gravimetric analysis confirmed that the Gaillardin interaction might improve the thermal stability of the NPs. The NPs demonstrated robust stability in various media, highlighting their potential as a delivery system. However, size increase in deionized water suggests the need for formulation optimization. Cell-based assays revealed selective cytotoxicity towards A-375 melanoma cancer cells with minimal impact on non-cancerous HaCaT cells, indicating targeted antitumor effects. Real-time PCR showed gene expression changes consistent with antitumor activity and immune response modulation. The findings suggest that IFN-γ-Gaillardin NPs have potent antitumor properties and the ability to modulate the immune system, warranting further investigation into their therapeutic applications. The development of an IFN-γ-based nanocarrier system for Gaillardin delivery offers a promising approach to melanoma therapy, setting a new direction for NP-based cancer treatment strategies.

Inflammasome activation in patients with Kaposi sarcoma herpesvirus-associated diseases

ABSTRACT

Kaposi sarcoma herpesvirus (KSHV)-associated diseases include Kaposi sarcoma (KS), primary effusion lymphoma (PEL), KSHV-associated multicentric Castleman disease (MCD), and KS inflammatory cytokine syndrome (KICS). PEL, MCD, and KICS are associated with elevated circulating inflammatory cytokines. However, activation of the inflammasome, which generates interleukin-1β (IL-1β) and IL-18 via active caspase-1/4/5, has not been evaluated in patients with KSHV-associated diseases (KADs). Herein we report that patients with HIV and ≥1 KAD present with higher plasma levels of IL-18 and increased caspase-1/4/5 activity in circulating monocytes compared with HIV-negative healthy volunteers (HVs) or people with HIV (PWH) without KAD. Within KAD subtypes, KICS and MCD shared enhanced caspase-1/4/5 activity and IL-18 production compared with HVs and PWH, whereas patients with PEL showed remarkably high levels of inflammasome complex formation (known as apoptosis-associated speck-like protein containing a caspase recruitment domain). Moreover, caspase-1/4/5 activity and IL-18 plasma levels correlated with KSHV viral load, indicating KSHV-driven inflammasome activation in KAD. Accordingly, factors released by cells latently infected with KSHV triggered inflammasome activation and cytokine production in bystander monocytes in vitro. Finally, both supervised and unsupervised analyses with inflammasome measurements and other inflammatory biomarkers demonstrate a unique inflammatory profile in patients with PEL, MCD, and KICS as compared with KS. Our data indicate that detrimental inflammation in patients with KAD is at least partially driven by KSHV-induced inflammasome activation in monocytes, thus offering novel approaches to diagnose and treat these complex disorders. These trials were registered at www.ClinicalTrials.gov as #NCT01419561, NCT00092222, NCT00006518, and NCT02147405.

In Vivo Biocompatibility of Synechococcus sp. PCC 7002-Integrated Scaffolds for Skin Regeneration

Cyanobacteria, commonly known as blue-green algae, are prevalent in freshwater systems and have gained interest for their potential in medical applications, particularly in skin regeneration. Among these, Synechococcus sp. strain PCC 7002 stands out because of its rapid proliferation and capacity to be genetically modified to produce growth factors. This study investigates the safety of Synechococcus sp. PCC 7002 when used in scaffolds for skin regeneration, focusing on systemic inflammatory responses in a murine model. We evaluated the following three groups: scaffolds colonized with genetically engineered bacteria producing hyaluronic acid, scaffolds with wild-type bacteria, and control scaffolds without bacteria. After seven days, we assessed systemic inflammation by measuring changes in cytokine profiles and lymphatic organ sizes. The results showed no significant differences in spleen, thymus, and lymph node weights, indicating a lack of overt systemic toxicity. Blood cytokine analysis revealed elevated levels of IL-6 and IL-1β in scaffolds with bacteria, suggesting a systemic inflammatory response, while TNF-α levels remained unaffected. Proteome profiling identified distinct cytokine patterns associated with bacterial colonization, including elevated inflammatory proteins and products, indicative of acute inflammation. Conversely, control scaffolds exhibited protein profiles suggestive of a rejection response, characterized by increased levels of cytokines involved in T and B cell activation. Our findings suggest that Synechococcus sp. PCC 7002 does not appear to cause significant systemic toxicity, supporting its potential use in biomedical applications. Further research is necessary to explore the long-term effects and clinical implications of these responses.

The application of metagenomics, radiomics and machine learning for diagnosis of sepsis

Introduction

Sepsis poses a serious threat to individual life and health. Early and accessible diagnosis and targeted treatment are crucial. This study aims to explore the relationship between microbes, metabolic pathways, and blood test indicators in sepsis patients and develop a machine learning model for clinical diagnosis.

Methods

Blood samples from sepsis patients were sequenced. α-diversity and β-diversity analyses were performed to compare the microbial diversity between the sepsis group and the normal group. Correlation analysis was conducted on microbes, metabolic pathways, and blood test indicators. In addition, a model was developed based on medical records and radiomic features using machine learning algorithms.

Results

The results of α-diversity and β-diversity analyses showed that the microbial diversity of sepsis group was significantly higher than that of normal group (p < 0.05). The top 10 microbial abundances in the sepsis and normal groups were Vitis vinifera, Mycobacterium canettii, Solanum pennellii, Ralstonia insidiosa, Ananas comosus, Moraxella osloensis, Escherichia coli, Staphylococcus hominis, Camelina sativa, and Cutibacterium acnes. The enriched metabolic pathways mainly included Protein families: genetic information processing, Translation, Protein families: signaling and cellular processes, and Unclassified: genetic information processing. The correlation analysis revealed a significant positive correlation (p < 0.05) between IL-6 and Membrane transport. Metabolism of other amino acids showed a significant positive correlation (p < 0.05) with Cutibacterium acnes, Ralstonia insidiosa, Moraxella osloensis, and Staphylococcus hominis. Ananas comosus showed a significant positive correlation (p < 0.05) with Poorly characterized and Unclassified: metabolism. Blood test-related indicators showed a significant negative correlation (p < 0.05) with microorganisms. Logistic regression (LR) was used as the optimal model in six machine learning models based on medical records and radiomic features. The nomogram, calibration curves, and AUC values demonstrated that LR performed best for prediction.

Discussion

This study provides insights into the relationship between microbes, metabolic pathways, and blood test indicators in sepsis. The developed machine learning model shows potential for aiding in clinical diagnosis. However, further research is needed to validate and improve the model.

MicroRNAs Regulate the Expression of Genes Related to the Innate Immune and Inflammatory Response in Rabbits Infected with Lagovirus europaeus GI.1 and GI.2 Genotypes

MicroRNAs (miR) are a group of small, non-coding RNAs of 17-25 nucleotides that regulate gene expression at the post-transcriptional level. Dysregulation of miRNA expression or function may contribute to abnormal gene expression and signaling pathways, leading to disease pathology. Lagovirus europaeus (L. europaeus) causes severe disease in rabbits called rabbit hemorrhagic disease (RHD). The symptoms of liver, lung, kidney, and spleen degeneration observed during RHD are similar to those of acute liver failure (ALF) and multi-organ failure (MOF) in humans. In this study, we assessed the expression of miRs and their target genes involved in the innate immune and inflammatory response. Also, we assessed their potential impact on pathways in L. europaeus infection-two genotypes (GI.1 and GI.2)-in the liver, lungs, kidneys, and spleen. The expression of miRs and target genes was determined using quantitative real-time PCR (qPCR). We assessed the expression of miR-155 (MyD88, TAB2, p65, NLRP3), miR-146a (IRAK1, TRAF6), miR-223 (TLR4, IKKα, NLRP3), and miR-125b (MyD88). We also examined biomarkers of inflammation: IL-1β, IL-6, TNF-α, and IL-18 in four tissues at the mRNA level. Our study shows that the main regulators of the innate immune and inflammatory response in L. europaeus/GI.1 and GI.2 infection, as well as RHD, are miR-155, miR-223, and miR-146a. During infection with L. europaeus/RHD, miR-155 has both pro- and anti-inflammatory effects in the liver and anti-inflammatory effects in the kidneys and spleen; miR-146a has anti-inflammatory effects in the liver, lungs and kidneys; miR-223 has anti-inflammatory effects in all tissues; however, miR-125b has anti-inflammatory effects only in the liver. In each case, such an effect may be a determinant of the pathogenesis of RHD. Our research shows that miRs may regulate three innate immune and inflammatory response pathways in L. europaeus infection. However, the result of this regulation may be influenced by the tissue microenvironment. Our research shows that infection of rabbits with L. europaeus/GI.1 and GI.2 genotypes causes an overexpression of two critical acute phase cytokines: IL-6 in all examined tissues and TNF-α (in the liver, lungs, and spleen). IL-1β was highly expressed only in the lungs after L. europaeus infection. These facts indicate a strong and rapid involvement of the local innate immune and inflammatory response in L. europaeus infection-two genotypes (GI.1 and GI.2)-and in the pathogenesis of RHD. Profile of biomarkers of inflammation in rabbits infected with L. europaeus/GI.1 and GI.2 genotypes are similar regarding the nature of changes but are different for individual tissues. Therefore, we propose three inflammation profiles for L. europaeus infection for both GI.1 and GI.2 genotypes (pulmonary, renal, liver, and spleen).

Evaluation of interleukin-6 in synovial fluid in periprosthetic joint infection of the elbow

PURPOSE

Searching for quick determinable biomarkers with high sensitivity and specificity is necessary to improve and optimise the early diagnosis of periprosthetic elbow infection (PEI). Therefore, this study's objective was to evaluate the diagnostic value of synovial fluid interleukin-6 (IL-6) levels for diagnosing PEI in total elbow arthroplasty.

METHOD

Twelve prospective enrolled patients underwent total elbow arthroplasty revision surgery, during which synovial fluid was obtained. Between the initial implantation and the revision procedure were 33.5 ± 41 months (range, 2-144 months). Synovial fluid was collected for immediate IL-6 analysis parallel to the revision surgery. Furthermore, microbiological samples were obtained and analysed. Two groups were defined based on the microbiological results: non-infection and infection group. The ability of synovial fluid IL-6 analysis to predict infection status was explored using receiver operating characteristic curves and further statistical analysis.

RESULTS

Synovial fluid IL-6 analysis had a good diagnostic accuracy of 83% for PEI with an area under the curve of 0,79 and an ideal cutoff value (determined using Youden's criterion) of 15244 pg/mL.

DISCUSSION

This is the first study to clinically evaluate IL-6 as a diagnostical marker for periprosthetic joint infection (PJI) in total elbow arthroplasty. Our results suggest a good accuracy and high sensitivity for IL-6 to identify a PEI. The analysis of IL-6 can improve surgical decision-making regarding managing total elbow arthroplasty in terms of one- or two-staged revision.

CONCLUSION

IL-6 can play an important role in the perioperative differentiation of infected and non-infected situations.

NLRP3 Inflammasome and Gut Dysbiosis Linking Diabetes Mellitus and Inflammatory Bowel Disease

Diabetes mellitus and inflammatory bowel disease are chronic conditions with significant overlap in their pathophysiology, primarily driven by chronic inflammation. Both diseases are characterized by an aberrant immune response and disrupted homeostasis in various tissues. However, it remains unclear which disease develops first, and which one contributes to the other. Diabetes mellitus increases the risk of inflammatory bowel disease and inflammatory bowel disease may increase the risk of developing diabetes. This review focuses on comprehensively discussing the factors commonly contributing to the pathogenesis of diabetes mellitus and inflammatory bowel disease to draw a relationship between them and the possibility of targeting common factors to attenuate the incidence of one if the other is present. A key player in the intersection of diabetes mellitus and inflammatory bowel disease is the NLRP3 inflammasome, which regulates the production of pro-inflammatory cytokines leading to prolonged inflammation and tissue damage. Additionally, toll-like receptors via sensing microbial components contribute to diabetes mellitus and inflammatory bowel disease by initiating inflammatory responses. Gut dysbiosis, a common link in both diseases, further intensifies inflammation and metabolic dysfunction. Alterations in gut microbiota composition affect intestinal permeability and immune modulation, perpetuating a vicious cycle of inflammation and disease progression by changing protein expression. The overlap in the underlying inflammatory mechanisms has led to the potential of targeting mediators of chronic inflammation using anti-inflammatory drugs and biologics that benefit both conditions or attenuate the incidence of one in the presence of the other.

Changes in the Expression of Genes Regulating the Response to Hypoxia, Inflammation, Cell Cycle, Apoptosis, and Epithelial Barrier Functioning during Colitis-Associated Colorectal Cancer Depend on Individual Hypoxia Tolerance

One of the factors contributing to colorectal cancer (CRC) development is inflammation, which is mostly hypoxia-associated. This study aimed to characterize the morphological and molecular biological features of colon tumors in mice that were tolerant and susceptible to hypoxia based on colitis-associated CRC (CAC). Hypoxia tolerance was assessed through a gasping time evaluation in a decompression chamber. One month later, the animals were experimentally modeled for colitis-associated CRC by intraperitoneal azoxymethane administration and three dextran sulfate sodium consumption cycles. The incidence of tumor development in the distal colon in the susceptible to hypoxia mice was two times higher and all tumors (100%) were represented by adenocarcinomas, while in the tolerant mice, only 14% were adenocarcinomas and 86% were glandular intraepithelial neoplasia. The tumor area assessed on serially stepped sections was statistically significantly higher in the susceptible animals. The number of macrophages, CD3-CD19+, CD3+CD4+, and NK cells in tumors did not differ between animals; however, the number of CD3+CD8+ and vimentin+ cells was higher in the susceptible mice. Changes in the expression of genes regulating the response to hypoxia, inflammation, cell cycle, apoptosis, and epithelial barrier functioning in tumors and the peritumoral area depended on the initial mouse's hypoxia tolerance, which should be taken into account for new CAC diagnostics and treatment approaches development.

Rapid identification of early infections in febrile patients after CD19 target CAR-T cell therapy for B-cell malignancies

BACKGROUND

CD19-targeted chimeric antigen receptor T (CAR-T) cell therapy stands out as a revolutionary intervention, exhibiting remarkable remission rates in patients with refractory/relapsed (R/R) B-cell malignancies. However, the potential side effects of therapy, particularly cytokine release syndrome (CRS) and infections, pose significant challenges due to their overlapping clinical features. Promptly distinguishing between CRS and infection post CD19 target CAR-T cell infusion (CTI) remains a clinical dilemma. Our study aimed to analyze the incidence of infections and identify key indicators for early infection detection in febrile patients within 30 days post-CTI for B-cell malignancies.

METHODS

In this retrospective cohort study, a cohort of 104 consecutive patients with R/R B-cell malignancies who underwent CAR-T therapy was reviewed. Clinical data including age, gender, CRS, ICANS, treatment history, infection incidence, and treatment responses were collected. Serum biomarkers procalcitonin (PCT), interleukin-6 (IL-6), and C-reactive protein (CRP) levels were analyzed using chemiluminescent assays. Statistical analyses employed Pearson's Chi-square test, t-test, Mann-Whitney U-test, Kaplan-Meier survival analysis, Cox proportional hazards regression model, Spearman rank correlation, and receiver operating characteristic (ROC) curve analysis to evaluate diagnostic accuracy and develop predictive models through multivariate logistic regression.

RESULTS

In this study, 38 patients (36.5%) experienced infections (30 bacterial, 5 fungal, and 3 viral) within the first 30 days of CAR T-cell infusion. In general, bacterial, fungal, and viral infections were detected at a median of 7, 8, and 9 days, respectively, after CAR T-cell infusion. Prior allogeneic hematopoietic cell transplantation (HCT) was an independent risk factor for infection (Hazard Ratio [HR]: 4.432 [1.262-15.565], P = 0.020). Furthermore, CRS was an independent risk factor for both infection ((HR: 2.903 [1.577-5.345], P < 0.001) and severe infection (9.040 [2.256-36.232], P < 0.001). Serum PCT, IL-6, and CRP were valuable in early infection prediction post-CAR-T therapy, particularly PCT with the highest area under the ROC curve (AUC) of 0.897. A diagnostic model incorporating PCT and CRP demonstrated an AUC of 0.903 with sensitivity and specificity above 83%. For severe infections, a model including CRS severity and PCT showed an exceptional AUC of 0.991 with perfect sensitivity and high specificity. Based on the aforementioned analysis, we proposed a workflow for the rapid identification of early infection during CAR-T cell therapy.

CONCLUSIONS

CRS and prior allogeneic HCT are independent infection risk factors post-CTI in febrile B-cell malignancy patients. Our identification of novel models using PCT and CRP for predicting infection, and PCT and CRS for predicting severe infection, offers potential to guide therapeutic decisions and enhance the efficacy of CAR-T cell therapy in the future.

Kinetics of cardiovascular and inflammatory biomarkers in paediatric dengue shock syndrome

Glycocalyx disruption and hyperinflammatory responses are implicated in the pathogenesis of dengue-associated vascular leak, however little is known about their association with clinical outcomes of patients with dengue shock syndrome (DSS). We investigated the association of vascular and inflammatory biomarkers with clinical outcomes and their correlations with clinical markers of vascular leakage. We performed a prospective cohort study in Viet Nam. Children ≥5 years of age with a clinical diagnosis of DSS were enrolled into this study. Blood samples were taken daily during ICU stay and 7-10 days after hospital discharge for measurements of plasma levels of Syndecan-1, Hyaluronan, Suppression of tumourigenicity 2 (ST-2), Ferritin, N-terminal pro Brain Natriuretic Peptide (NT-proBNP), and Atrial Natriuretic Peptide (ANP). The primary outcome was recurrent shock. Ninety DSS patients were enrolled. Recurrent shock occurred in 16 patients. All biomarkers, except NT-proBNP, were elevated at presentation with shock. There were no differences between compensated and decompensated DSS patients. Glycocalyx markers were positively correlated with inflammatory biomarkers, haematocrit, percentage haemoconcentration, and negatively correlated with stroke volume index. While Syndecan-1, Hyaluronan, Ferritin, and ST-2 improved with time, ANP continued to be raised at follow-up. Enrolment Syndecan-1 levels were observed to be associated with developing recurrent shock although the association did not reach the statistical significance at the P < 0.01 (OR = 1.82, 95% CI 1.07-3.35, P = 0.038). Cardiovascular and inflammatory biomarkers are elevated in DSS, correlate with clinical vascular leakage parameters and follow different kinetics over time. Syndecan-1 may have potential utility in risk stratifying DSS patients in ICU.

Causal associations of genetically predicted gut microbiota and blood metabolites with inflammatory states and risk of infections: a Mendelian randomization analysis

Background

Inflammation serves as a key pathologic mediator in the progression of infections and various diseases, involving significant alterations in the gut microbiome and metabolism. This study aims to probe into the potential causal relationships between gut microbial taxa and human blood metabolites with various serum inflammatory markers (CRP, SAA1, IL-6, TNF-α, WBC, and GlycA) and the risks of seven common infections (gastrointestinal infections, dysentery, pneumonia, bacterial pneumonia, bronchopneumonia and lung abscess, pneumococcal pneumonia, and urinary tract infections).

Methods

Two-sample Mendelian randomization (MR) analysis was performed using inverse variance weighted (IVW), maximum likelihood, MR-Egger, weighted median, and MR-PRESSO.

Results

After adding other MR models and sensitivity analyses, genus Roseburia was simultaneously associated adversely with CRP (Beta IVW = -0.040) and SAA1 (Beta IVW = -0.280), and family Bifidobacteriaceae was negatively associated with both CRP (Beta IVW = -0.034) and pneumonia risk (Beta IVW = -0.391). After correction by FDR, only glutaroyl carnitine remained significantly associated with elevated CRP levels (Beta IVW = 0.112). Additionally, threonine (Beta IVW = 0.200) and 1-heptadecanoylglycerophosphocholine (Beta IVW = -0.246) were found to be significantly associated with WBC levels. Three metabolites showed similar causal effects on different inflammatory markers or infectious phenotypes, stearidonate (18:4n3) was negatively related to SAA1 and urinary tract infections, and 5-oxoproline contributed to elevated IL-6 and SAA1 levels. In addition, 7-methylguanine showed a positive correlation with dysentery and bacterial pneumonia.

Conclusion

This study provides novel evidence confirming the causal effects of the gut microbiome and the plasma metabolite profile on inflammation and the risk of infection. These potential molecular alterations may aid in the development of new targets for the intervention and management of disorders associated with inflammation and infections.

Sphingolipid-Induced Bone Regulation and Its Emerging Role in Dysfunction Due to Disease and Infection

The human skeleton is a metabolically active system that is constantly regenerating via the tightly regulated and highly coordinated processes of bone resorption and formation. Emerging evidence reveals fascinating new insights into the role of sphingolipids, including sphingomyelin, sphingosine, ceramide, and sphingosine-1-phosphate, in bone homeostasis. Sphingolipids are a major class of highly bioactive lipids able to activate distinct protein targets including, lipases, phosphatases, and kinases, thereby conferring distinct cellular functions beyond energy metabolism. Lipids are known to contribute to the progression of chronic inflammation, and notably, an increase in bone marrow adiposity parallel to elevated bone loss is observed in most pathological bone conditions, including aging, rheumatoid arthritis, osteoarthritis, and osteomyelitis. Of the numerous classes of lipids that form, sphingolipids are considered among the most deleterious. This review highlights the important primary role of sphingolipids in bone homeostasis and how dysregulation of these bioactive metabolites appears central to many chronic bone-related diseases. Further, their contribution to the invasion, virulence, and colonization of both viral and bacterial host cell infections is also discussed. Many unmet clinical needs remain, and data to date suggest the future use of sphingolipid-targeted therapy to regulate bone dysfunction due to a variety of diseases or infection are highly promising. However, deciphering the biochemical and molecular mechanisms of this diverse and extremely complex sphingolipidome, both in terms of bone health and disease, is considered the next frontier in the field.

PLGA-Chitosan Encapsulated IL-10 Nanoparticles Modulate Chlamydia Inflammation in Mice

Introduction

Interleukin-10 (IL-10) is a key anti-inflammatory mediator in protecting host from over-exuberant responses to pathogens and play important roles in wound healing, autoimmunity, cancer, and homeostasis. However, its application as a therapeutic agent for biomedical applications has been limited due to its short biological half-life. Therefore, it is important to prolong the half-life of IL-10 to replace the current therapeutic application, which relies on administering large and repeated dosages. Therefore, not a cost-effective approach. Thus, studies that aim to address this type of challenges are always in need.

Methods

Recombinant IL-10 was encapsulated in biodegradable nanoparticles (Poly-(Lactic-co-Glycolic Acid) and Chitosan)) by the double emulsion method and then characterized for size, surface charge, thermal stability, cytotoxicity, in vitro release, UV-visible spectroscopy, and Fourier Transform-Infrared Spectroscopy as well as evaluated for its anti-inflammatory effects. Bioactivity of encapsulated IL-10 was evaluated in vitro using J774A.1 macrophage cell-line and in vivo using BALB/c mice. Inflammatory cytokines (IL-6 and TNF-α) were quantified from culture supernatants using specific enzyme-linked immunosorbent assay (ELISA), and significance was analyzed using ANOVA.

Results

We obtained a high 96% encapsulation efficiency with smooth encapsulated IL-10 nanoparticles of ~100-150 nm size and release from nanoparticles as measurable to 22 days. Our result demonstrated that encapsulated IL-10 was biocompatible and functional by reducing the inflammatory responses induced by LPS in macrophages. Of significance, we also proved the functionality of encapsulated IL-10 by its capacity to reduce inflammation in BALB/c mice as provoked by Chlamydia trachomatis, an inflammatory sexually transmitted infectious bacterium.

Discussion

Collectively, our results show the successful IL-10 encapsulation, slow release to prolong its biological half-life and reduce inflammatory cytokines IL-6 and TNF production in vitro and in mice. Our results serve as proof of concept to further explore the therapeutic prospective of encapsulated IL-10 for biomedical applications, including inflammatory diseases.

Molecular cloning, characterization and expression analysis of the Chinese soft-shelled turtle (Pelodiscus sinensis) chemokine CXCL11

Chemokines are small, secreted proteins with chemoattractive properties, which play an important role in the recruitment and activation of immune cells. CXCL11 is a CXC chemokine specific for the CXCR3 receptors, which has been shown to mediate the generation of Th1-type immune responses and have bactericidal effects similar to defensins. Herein, we cloned the full-length cDNA of Chinese soft-shelled turtle (Pelodiscus sinensis) CXCL11, designated as PsCXCL11, which consist of an open reading frame (ORF) of 282 bp encoding 93 amino acids, with estimated molecular weight of 10.055 kDa and isoelectric point of 10.37. The deduced PsCXCL11 sequence had a signal peptide, a highly conserved family-specific small cytokine (SCY) domain, one putative N-glycosylation site and ten potential phosphorylation sites. Phylogenetic analysis showed a close relationship between P. sinensis and Chelydra Serpentina CXCL11. P. sinensis CXCL11 basal expression levels were higher in heart, kidney and spleen than in other organs of health turtles. Infections of Aeromonas hydrophila and Staphylococcus aureus led to significant upregulation of P. sinensis CXCL11 in the blood, while significant upregulation of PsCXCL11 were observed in liver and spleen after infection of A. hydrophila, but not S. aureus. PsCXCL11 recombinant protein with His-tag was successfully expressed by an auto-inducible expression system, and purified by Ni-NTA affinity chromatography. These findings laid a solid foundation for further research towards development of the Chinese soft-shelled turtle as a model for the role of CXCL11 in regulating inflammatory responses to stimulation by invading pathogens.

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome.

Nerve Growth Factor and the Role of Inflammation in Tumor Development

Nerve growth factor (NGF) plays a dual role both in inflammatory states and cancer, acting both as a pro-inflammatory and oncogenic factor and as an anti-inflammatory and pro-apoptotic mediator in a context-dependent way based on the signaling networks and its interaction with diverse cellular components within the microenvironment. This report aims to provide a summary and subsequent review of the literature on the role of NGF in regulating the inflammatory microenvironment and tumor cell growth, survival, and death. The role of NGF in inflammation and tumorigenesis as a component of the inflammatory system, its interaction with the various components of the respective microenvironments, its ability to cause epigenetic changes, and its role in the treatment of cancer have been highlighted in this paper.

Association of mTOR Pathway and Conformational Alterations in C-Reactive Protein in Neurodegenerative Diseases and Infections

Inflammatory biomarkers have been very useful in detecting and monitoring inflammatory processes along with providing helpful information to select appropriate therapeutic strategies. C-reactive protein (CRP) is a nonspecific, but quite useful medical acute inflammatory biomarker and is associated with persistent chronic inflammatory processes. Several studies suggest that different levels of CRP are correlated with neurological disorders such as Alzheimer's disease (AD). However, dynamics of CRP levels have also been observed in virus/bacterial-related infections leading to inflammatory responses and this triggers mTOR-mediated pathways for neurodegeneration diseases. The biophysical structural transition from CRP to monomeric CRP (mCRP) and the significance of the ratio of CRP levels on the onset of symptoms associated with inflammatory response have been discussed. In addition, mTOR inhibitors act as immunomodulators by downregulating the expression of viral infection and can be explored as a potential therapy for neurological diseases.

Long-term efficacy and safety of canakinumab in the treatment of systemic juvenile idiopathic arthritis in Japanese patients: Results from an open-label Phase III study

OBJECTIVES

The objective of the study was to report the efficacy and safety of canakinumab treatment in Japanese patients with systemic juvenile idiopathic arthritis (sJIA) over a 48-week study period.

METHODS

Patients were administered canakinumab 4 mg/kg (maximum dose 300 mg) every 4 weeks, with no dose adjustments. The key outcome measures included adapted American College of Rheumatology paediatric (aACR pedi) 30/50/70/90/100 response, proportion of patients with inactive disease, and corticosteroid (CS) tapering.

RESULTS

In total, 16/19 (84.2%) patients received canakinumab for ≥96 weeks reaching end-of-study (EOS) visit without premature discontinuation. Regardless of the level of joint involvement at baseline, high aACR pedi responses were observed throughout the study; at the EOS, aACR pedi 90/100 response rates were 84.2%/63.2%, respectively. The proportion of patients who successfully tapered CSs at EOS was 66.7% (12/18), of which 10 patients were steroid-free. The most common adverse events were infections (238.3 events/100 patient-years). Serious adverse events were observed in 52.6%. The event (n=1) adjudicated as possible macrophage activation syndrome was preceded by sJIA flare. No deaths were reported.

CONCLUSIONS

Canakinumab treatment resulted in a sustained treatment response in sJIA patients over 48 weeks and was associated with CS tapering in majority of patients. No new safety findings were reported.

Immunological Profile of Serum Antibodies, Multiplex Cytokines, and Complement Proteins in Cystic Echinococcosis Patients

Background:

Cystic echinococcosis (CE) is a zoonotic parasite disease that affects people globally and causes cysts to develop in internal organs.

Objectives:

This study aimed to examine the effects of E. granulosus infection on the level of some immunological cytokines such as IL-2, IL-4, and IL-6 and the level of IgM and IgG antibodies as well as to investigate the effects of hydatid cysts disease on complement proteins.

Materials and Methods:

This case–control study was carried out on 46 individuals whose ages ranged between 20 and 70. The study extended from September 2021 to May 2022. Forty-six blood samples were collected from patients infected with hydatidosis and 10 blood samples from non-infected as a control group. The blood samples were used to obtain the desired sera for immunological detection: immunoglobulins (IgM and IgG); interleukins (IL-2, IL-4, and IL-6) by using enzyme-linked immunosorbent assay and complement proteins (by using radial immnodiffusion plate).

Results:

The level of anti-echinococcosis IgM (304.7 ± 73.4 mg/dL) was higher in infected than uninfected persons (161.8 ± 14.2 mg/dL). Anti-echinococcosis IgG level in an infected individual (1587.3 ± 449.4 mg/dL) was higher when compared with control (1136 ± 25.4 mg/dL). The highest number of cases (19, 41.30%) was observed in age 41–50 years, followed by the age 31–40 years (11, 17.18%). The results showed a high increase in the incidence of infection with hydatid cyst among men (58.69%) in comparison to women (41.30%). The patients most at risk are those living in intimate association with animals’ environments. Three cytokines including (IL-6, IL-4, and IL-2) were significantly elevated (474.8 ± 116, 6.86 ± 0.6, and 7.01 ± 2.89 pg/mL) in patients with hydatidosis disease in comparison with the normal controls (118.4 ± 14.3, 6.11 ± 0.3, and 4.54 ± 0.4 pg/mL). Examining the complement protein production, we found that C3 and C4 were significantly higher (159.5 ± 51.6 and 36.15 ± 6.13 mg/dL) in patients with hydatidosis than those of controls (117.7 ± 8.1 and 26.4 ± 3.1).

Conclusions:

Our findings provide information on the effects of E. granulosis parasite on the profile of serum antibodies, multiplex cytokines, and complement proteins in cystic echinococcosis patients.

Morphological and Molecular Biological Features of the Systemic Inflammatory Response in Old Wistar Rats with High and Low Resistance to Hypoxia

Morphological and molecular biological features of LPS-induced systemic inflammatory response were assessed in old male Wistar rats with high (HR) and low (LR) resistance to hypoxia. The systemic inflammatory response was modeled by intraperitoneal injection of E. coli O26:B6 LPS; the animals were sacrificed after 6 h. In histological sections, the number of neutrophils in the interalveolar septa and the area of necrosis in the liver were determined. The expression levels of Hif1a, Hif2a, Nfkb, Vegf, Il1b, Il6, Il10, and Tgfb mRNA in the liver and serum concentrations of HIF-1α and IL-1β were determined. In 4-6 h after LPS injection, 3 (43%) of 7 HR rats died, whereas no deaths were observed among LR rats. At 6 h after LPS injection, the number of neutrophils in the interalveolar septa of the lungs in LR rats was significantly higher than in HR rats, while the area of necrosis in the liver did not differ. At the same time, the mRNA expression levels of the proinflammatory cytokine genes Il1b and Il6 increased in the liver of both HR and LR rats, whereas the expression of Il10 increased only in HR rats. The expression of the Hif1a gene in the liver was higher in LR rats, but the content of HIF-1α protein in blood serum was higher in HR animals. These data should be taken into account when developing new approaches to the therapy of systemic inflammatory response in infectious and inflammatory diseases in the elderly.

Depression and HIV: a scoping review in search of neuroimmune biomarkers

People with HIV are at increased risk for depression, though the neurobiological mechanisms underlying this are unclear. In the last decade, there has been a substantial rise in interest in the contribution of (neuro)inflammation to depression, coupled with rapid advancements in the resolution and sensitivity of biomarker assays such as Luminex, single molecular array and newly developed positron emission tomography radioligands. Numerous pre-clinical and clinical studies have recently leveraged these next-generation immunoassays to identify biomarkers that may be associated with HIV and depression (separately), though few studies have explored these biomarkers in co-occurring HIV and depression. Using a systematic search, we detected 33 publications involving a cumulative N = 10 590 participants which tested for associations between depressive symptoms and 55 biomarkers of inflammation and related processes in participants living with HIV. Formal meta-analyses were not possible as statistical reporting in the field was highly variable; future studies must fully report test statistics and effect size estimates. The majority of included studies were carried out in the United States, with samples that were primarily older and primarily men. Substantial further work is necessary to diversify the geographical, age, and sex distribution of samples in the field. This review finds that alterations in concentrations of certain biomarkers of neuroinflammation (interleukin-6, tumour necrosis factor-α, neopterin) may influence the association between HIV and depression. Equally, the chemokines monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) or the metabolic index kynurenine:tryptophan (Kyn:Trp), which have been the focus of several studies, do not appear to be associated with depressive symptoms amongst people living with HIV, as all (MCP-1) or most (IL-8 and Kyn:Trp) available studies of these biomarkers reported non-significant associations. We propose a biomarker-driven hypothesis of the neuroimmunometabolic mechanisms that may precipitate the increased risk of depression among people with HIV. Chronically activated microglia, which trigger key neuroinflammatory cascades shown to be upregulated in people with HIV, may be the central link connecting HIV infection in the central nervous system with depressive symptoms. Findings from this review may inform research design in future studies of HIV-associated depression and enable concerted efforts towards biomarker discovery.

Multilayer omics reveals the molecular mechanism of early infection of Clonorchis sinensis juvenile

BACKGROUND

Clonorchiasis remains a non-negligible global zoonosis, causing serious socioeconomic burdens in endemic areas. Clonorchis sinensis infection typically elicits Th1/Th2 mixed immune responses during the course of biliary injury and periductal fibrosis. However, the molecular mechanism by which C. sinensis juvenile initially infects the host remains poorly understood.

METHODS

The BALB/c mouse model was established to study early infection (within 7 days) with C. sinensis juveniles. Liver pathology staining and observation as well as determination of biochemical enzymes, blood routine and cytokines in blood were conducted. Furthermore, analysis of liver transcriptome, proteome and metabolome changes was performed using multi-omics techniques. Statistical analyses were performed using Student's t-test.

RESULTS

Histopathological analysis revealed that liver injury, characterized by collagen deposition and inflammatory cell infiltration, occurred as early as 24 h of infection. Blood indicators including ALT, AST, WBC, CRP and IL-6 indicated that both liver injury and systemic inflammation worsened as the infection progressed. Proteomic data showed that apoptosis and junction-related pathways were enriched within 3 days of infection, indicating the occurrence of liver injury. Furthermore, proteomic and transcriptomic analysis jointly verified that the detoxification and antioxidant defense system was activated by enrichment of glutathione metabolism and cytochrome P450-related pathways in response to acute liver injury. Proteomic-based GO analysis demonstrated that biological processes such as cell deformation, proliferation, migration and wound healing occurred in the liver during the early infection. Correspondingly, transcriptomic results showed significant enrichment of cell cycle pathway on day 3 and 7. In addition, the KEGG analysis of multi-omics data demonstrated that numerous pathways related to immunity, inflammation, tumorigenesis and metabolism were enriched in the liver. Besides, metabolomic screening identified several metabolites that could promote inflammation and hepatobiliary periductal fibrosis, such as CA7S.

CONCLUSIONS

This study revealed that acute inflammatory injury was rapidly triggered by initial infection by C. sinensis juveniles in the host, accompanied by the enrichment of detoxification, inflammation, fibrosis, tumor and metabolism-related pathways in the liver, which provides a new perspective for the early intervention and therapy of clonorchiasis.

Antibody-Mediated Clearance of Brain Amyloid-β: Mechanisms of Action, Effects of Natural and Monoclonal Anti-Aβ Antibodies, and Downstream Effects

Immunotherapeutic efforts to slow the clinical progression of Alzheimer's disease (AD) by lowering brain amyloid-β (Aβ) have included Aβ vaccination, intravenous immunoglobulin (IVIG) products, and anti-Aβ monoclonal antibodies. Neither Aβ vaccination nor IVIG slowed disease progression. Despite conflicting phase III results, the monoclonal antibody Aducanumab received Food and Drug Administration (FDA) approval for treatment of AD in June 2021. The only treatments unequivocally demonstrated to slow AD progression to date are the monoclonal antibodies Lecanemab and Donanemab. Lecanemab received FDA approval in January 2023 based on phase II results showing lowering of PET-detectable Aβ; phase III results released at that time indicated slowing of disease progression. Topline results released in May 2023 for Donanemab's phase III trial revealed that primary and secondary end points had been met. Antibody binding to Aβ facilitates its clearance from the brain via multiple mechanisms including promoting its microglial phagocytosis, activating complement, dissolving fibrillar Aβ, and binding of antibody-Aβ complexes to blood-brain barrier receptors. Antibody binding to Aβ in peripheral blood may also promote cerebral efflux of Aβ by a peripheral sink mechanism. According to the amyloid hypothesis, for Aβ targeting to slow AD progression, it must decrease downstream neuropathological processes including tau aggregation and phosphorylation and (possibly) inflammation and oxidative stress. This review discusses antibody-mediated mechanisms of Aβ clearance, findings in AD trials involving Aβ vaccination, IVIG, and anti-Aβ monoclonal antibodies, downstream effects reported in those trials, and approaches which might improve the Aβ-clearing ability of monoclonal antibodies.

Serum ferritin level during hospitalization is associated with Brain Fog after COVID-19

The coronavirus disease 2019 (COVID-19) remains an epidemic worldwide. Most patients suffer residual symptoms, the so-called "Long COVID," which includes respiratory and neuropsychiatric symptoms. Brain Fog, one of the symptoms of Long COVID, is a major public health issue because it can impair patients' quality of life even after recovery from the disease. However, neither the pathogenesis nor the treatment of this condition remains unknown. We focused on serum ferritin levels in this study and collected information on the onset of Brain Fog through questionnaires and found that high ferritin levels during hospitalization were associated with the occurrence of Brain Fog. In addition, we excluded confounders as far as possible using propensity score analyses and found that ferritin was independently associated with Brain Fog in most of the models. We conducted phase analysis and evaluated the interaction of each phase with ferritin levels and Brain Fog. We found a positive correlation between serum ferritin levels during hospitalization and Brain Fog after COVID-19. High ferritin levels in patients with Brain Fog may reflect the contribution of chronic inflammation in the development of Brain Fog. This study provides a novel insight into the pathogenic mechanism of Brain Fog after COVID-19.

Influenza breakthrough infection in vaccinated mice is characterized by non-pathological lung eosinophilia

Eosinophils are important mediators of mucosal tissue homeostasis, anti-helminth responses, and allergy. Lung eosinophilia has previously been linked to aberrant Type 2-skewed T cell responses to respiratory viral infection and may also be a consequence of vaccine-associated enhanced respiratory disease (VAERD), particularly in the case of respiratory syncytial virus (RSV) and the formalin-inactivated RSV vaccine. We previously reported a dose-dependent recruitment of eosinophils to the lungs of mice vaccinated with alum-adjuvanted trivalent inactivated influenza vaccine (TIV) following a sublethal, vaccine-matched H1N1 (A/New Caledonia/20/1999; NC99) influenza challenge. Given the differential role of eosinophil subset on immune function, we conducted the investigations herein to phenotype the lung eosinophils observed in our model of influenza breakthrough infection. Here, we demonstrate that eosinophil influx into the lungs of vaccinated mice is adjuvant- and sex-independent, and only present after vaccine-matched sublethal influenza challenge but not in mock-challenged mice. Furthermore, vaccinated and challenged mice had a compositional shift towards more inflammatory eosinophils (iEos) compared to resident eosinophils (rEos), resembling the shift observed in ovalbumin (OVA)-sensitized allergic control mice, however without any evidence of enhanced morbidity or aberrant inflammation in lung cytokine/chemokine signatures. Furthermore, we saw a lung eosinophil influx in the context of a vaccine-mismatched challenge. Additional layers of heterogeneity in the eosinophil compartment were observed via unsupervised clustering analysis of flow cytometry data. Our collective findings are a starting point for more in-depth phenotypic and functional characterization of lung eosinophil subsets in the context of vaccine- and infection-induced immunity.

Interleukin 18 and IL-18 BP response to Sars-CoV-2 virus infection

The immune response to the SARS-CoV-2 infection is crucial to the patient outcome. IL-18 is involved in the lymphocyte response to the disease and it is well established its important role in the complex developing of the host response to viral infection. This study aims at the analysis of the concentrations of IL-18, IL-18BP, INF-γ at the onset of the SARS-CoV-2 infection. The serum levels of measured interleukins were obtained through enzyme-linked immunosorbent assay. Furthermore, the free fraction of IL-18 was numerically evaluated. The enrolled patients were divided in two severity groups according to a threshold value of 300 for the ratio of arterial partial pressure of oxygen and fraction of inspired oxygen fraction and according to the parenchymal involvement as evaluated by computerized tomography at the admittance. In the group of patients with a more severe disease, a significant increase of the IL-18, INF-γ and IL-18BP levels have been observed, whereas the free IL-18 component values were almost constant. The results confirm that, at the onset of the disease, the host response keep the inflammatory cytokines in an equilibrium and support the hypothesis to adopt the IL-18BP modulation as a possible and effective therapeutic approach.

NLRP3, the inflammasome and COVID-19 infection

Severe coronavirus disease 2019 (COVID-19) is characterized by respiratory failure, shock or multiorgan dysfunction, often accompanied by systemic hyperinflammation and dysregulated cytokine release. These features are linked to the intense and rapid stimulation of the innate immune response. The NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is a central player in inflammatory macrophage activation which via caspase-1 activation leads to the release of the mature forms of the proinflammatory cytokines interleukin (IL)-1β and IL-18, and via cleavage of Gasdermin D pyroptosis, an inflammatory form of cell death. Here, we discuss the role of NLRP3 activation in COVID-19 and clinical trials currently underway to target NLRP3 to treat severe COVID-19.

Normoferremia in Patients with Acute Bacterial Infections-A Hitherto Unexplored Field of the Dichotomy between CRP and Ferritin Expression in Patients with Hyper Inflammation and Failure to Increase Ferritin

Ferritin is an acute phase response protein, which may not rise as expected in acute bacterial infections. This could be due to the time required for its production or to a lack of response of ferritin to the bacterial inflammatory process. Medical records of hospitalized patients with acute hyper inflammation were retrieved and studied, looking closely at two acute phase proteins: C-reactive protein (CRP) and ferritin. The estimated time between symptom onset and the procurement of blood tests was also measured. 225 patients had a median ferritin level of 109.9 ng/mL [IQR 85.1, 131.7] and a median CRP level of 248.4 mg/L [IQR 221, 277.5]. An infectious inflammatory process was identified in 195 patients. Ferritin levels were relatively low in comparison with the CRP in each group, divided according to time from symptom onset until the procurement of blood tests. The discrepancy between high CRP and low ferritin suggests that these two acute phase response proteins utilize different pathways, resulting in a failure to increase ferritin concentrations in a documented state of hyperinflammation. A new entity of normoferremic inflammation accounts for a significant percentage of patients with acute bacterial infections, which enables bacteria to better survive the inflammation and serves as a new "inflammatory stamp".

Future Biomarkers for Infection and Inflammation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) increases the susceptibility to a variety of infections that are often difficult to diagnose and can be asymptomatic or symptoms are atypical. Usually, this is a great challenge for rheumatologists, because it is difficult to distinguish infection and aseptic inflammation at an early stage. Prompt diagnosis and treatment of bacterial infections in immunosuppressed individuals is critical for clinicians, and early exclusion of infection allows for specific treatment of inflammatory diseases and avoids the unnecessary use of antibiotics. However, for patients with clinically suspected infection, traditional laboratory markers are not specific for bacterial infection and cannot be used to distinguish outbreaks from infections. Therefore, new infection markers that can distinguish infection from underlying disease are urgently needed for clinical practice. Here, we review the novel biomarkers in RA patients with infection. These biomarkers include presepsin, serology and haematology, as well as neutrophils, T cells, and natural killer cells. Meanwhile, we discuss meaningful biomarkers that distinguish infection from inflammation and develop novel biomarkers for clinical applications, allowing clinicians to make better decisions when diagnosing and treating RA.

T-cell-derived TNF-α and a cluster of immunological parameters from plasma allow a separation between SARS-CoV-2 convalescent versus vaccinated elite athletes

Guidelines for medical clearing after SARS-CoV-2 infection in elite athletes do not include T-cell immunity aspects despite its relevance in the course of COVID-19 disease. Therefore, we aimed to analyze T-cell-related cytokines before and after in-vitro activation of CD4⁺ T-cells. We sampled professional indoor sports athletes at medical clearing after SARS-CoV-2 infection obtaining clinical, fitness data, and serological data including CD4⁺ T-cell cytokines. All data were analyzed by principal component analysis and 2 × 2 repeated measures ANOVA. CD4⁺ T-cells were sampled for cell culture activation with anti-CD3/anti-CD28 tetramers. At medical clearing, CD4⁺ T-cells from convalescent athletes secreted increased levels of TNF-α 72 h after in-vitro activation compared to vaccinated athletes. IL-18 levels in plasma were elevated and a cluster of parameters differentiated convalescent from vaccinated athletes by 13 parameters at the timepoint of medical clearing. All clinical data indicate infection is resolved, while increased TNF-α may reflect altered proportions of peripheral T-cells as a hangover of infection.

Insights into the Role of Plasmatic and Exosomal microRNAs in Oxidative Stress-Related Metabolic Diseases

A common denominator of metabolic diseases, including type 2 diabetes Mellitus, dyslipidemia, and atherosclerosis, are elevated oxidative stress and chronic inflammation. These complex, multi-factorial diseases are caused by the detrimental interaction between the individual genetic background and multiple environmental stimuli. The cells, including the endothelial ones, acquire a preactivated phenotype and metabolic memory, exhibiting increased oxidative stress, inflammatory gene expression, endothelial vascular activation, and prothrombotic events, leading to vascular complications. There are different pathways involved in the pathogenesis of metabolic diseases, and increased knowledge suggests a role of the activation of the NF-kB pathway and NLRP3 inflammasome as key mediators of metabolic inflammation. Epigenetic-wide associated studies provide new insight into the role of microRNAs in the phenomenon of metabolic memory and the development consequences of vessel damage. In this review, we will focus on the microRNAs related to the control of anti-oxidative enzymes, as well as microRNAs related to the control of mitochondrial functions and inflammation. The objective is the search for new therapeutic targets to improve the functioning of mitochondria and reduce oxidative stress and inflammation, despite the acquired metabolic memory.

Clinical implications of circulating follistatin-like protein-1 in hemodialysis patients

Follistatin-like protein-1 (FSTL-1) is secreted glycoprotein, which regulates cardiovascular, immune and skeletal system. However, the clinical significance of circulating FSTL-1 levels remains unclear in hemodialysis patients. A total 376 hemodialysis patients were enrolled from June 2016 to March 2020. Plasma FSTL-1 level, inflammatory biomarkers, physical performance, and echocardiographic findings at baseline were examined. Plasma FSTL-1 levels were positively correlated with TNF-α and MCP-1. Handgrip strength showed weak positive correlation in male patients only, and gait speed showed no correlation with FSTL-1 levels. In multivariate linear regression analysis, FSTL-1 level was negatively associated with left ventricular ejection fraction (β =  - 0.36; p = 0.011). The cumulative event rate of the composite of CV event and death, and cumulative event rate of CV events was significantly greater in FSTL-1 tertile 3. In multivariate Cox-regression analysis, FSTL-1 tertile 3 was associated with a 1.80-fold risk for the composite of CV events and death(95% confidence interval (CI) 1.06-3.08), and a 2.28-fold risk for CV events (95% CI 1.15-4.51) after adjustment for multiple variables. In conclusion, high circulating FSTL-1 levels independently predict the composite of CV events and death, and FSTL-1 level was independently associated with left ventricular systolic dysfunction.

Toxoplasma gondii profilin induces NLRP3 activation and IL-1β production/secretion in THP-1 cells

Toxoplasma gondii is a highly prevalent protozoan that infects a broad spectrum of warm-blooded animals. Profilin is a critical protein that plays a role in the movement and invasion of T. gondii. In the current study, we assessed how profilin stimulates inflammasomes and how it induces transcription and secretion of IL-1β. For this purpose, we assessed the level of TLR 2, 4, 5, and 9 expressions in a THP-1 cell line treated with profilin from T. gondii (TgP). In addition, we analyzed the expression levels of various inflammasomes, as well as IL-1β, and IL-18 in THP-1 cells treated with the NLRP3 inhibitor MCC950. TgP significantly increased the expression of TLR5 but the expression of TLR2, 4, and 9 was not significantly increased. In addition, TgP did not significantly increase the level of inflammasomes after 5 h. Treatment with MCC950 significantly reduced NLRP3 and IL-1β on both transcription and protein levels. Although the transcription level of NLRP3 was reduced 5 h after treatment with TgP, western blot analysis showed an increase in NLRP3. The western blot and ELISA analysis also showed that TgP increased both pro- and mature IL-1β. In summary, our study showed that NLRP3 most probably plays a pivotal role in the expression and production levels of IL-1β during the interaction between TgP and macrophages.

CD169 expression on monocytes as a marker for assessing type I interferon status in pediatric inflammatory diseases

BACKGROUND

Evaluation of type I interferons (IFNs) in inflammatory or autoimmune diseases is challenging because of their rapid clearance in peripheral blood. The IFN gene expression signature has recently been used to evaluate the IFN status; however, this is often a labor-intensive and time-consuming procedure. Therefore, we assessed the feasibility of measuring expression of an IFN-inducible protein, CD169 (Siglec-1), on monocytes and circulating levels of soluble CD169 as alternative markers for type I IFN status in various pediatric inflammatory diseases.

METHODS

Data from flow cytometric analysis of surface CD169 on monocytes and an enzyme-linked immunosorbent assay of soluble CD169 in peripheral blood were compared with serum IFN-α levels in 8 patients with viral infections, 5 with bacterial infections, 10 with systemic lupus erythematosus (SLE), 5 with Kikuchi-Fujimoto disease (KFD), 7 with Kawasaki disease (KD), and 8 with inflammatory bowel disease (IBD), and in 8 healthy controls.

RESULTS

Surface CD169 expression was detected mainly on CD14⁺ monocytes and was significantly increased in patients with viral infections, SLE, and KFD, but not in patients with bacterial infections, KD, and IBD. There were similar trends for circulating soluble CD169; however, there was a significant increase only in patients with viral infections. Surface CD169 levels were significantly correlated with serum levels of IFN-α and soluble CD169.

CONCLUSION

Analysis of CD169 expression on CD14⁺ monocytes may be useful for rapid assessment of type I IFN status for differentiation of pediatric inflammatory diseases from type 1 IFN-mediated diseases.

Smuggling on the Nanoscale-Fusogenic Liposomes Enable Efficient RNA-Transfer with Negligible Immune Response In Vitro and In Vivo

The efficient and biocompatible transfer of nucleic acids into mammalian cells for research applications or medical purposes is a long-standing, challenging task. Viral transduction is the most efficient transfer system, but often entails high safety levels for research and potential health impairments for patients in medical applications. Lipo- or polyplexes are commonly used transfer systems but result in comparably low transfer efficiencies. Moreover, inflammatory responses caused by cytotoxic side effects were reported for these transfer methods. Often accountable for these effects are various recognition mechanisms for transferred nucleic acids. Using commercially available fusogenic liposomes (Fuse-It-mRNA), we established highly efficient and fully biocompatible transfer of RNA molecules for in vitro as well as in vivo applications. We demonstrated bypassing of endosomal uptake routes and, therefore, of pattern recognition receptors that recognize nucleic acids with high efficiency. This may underlie the observed almost complete abolishment of inflammatory cytokine responses. RNA transfer experiments into zebrafish embryos and adult animals fully confirmed the functional mechanism and the wide range of applications from single cells to organisms.

The roles of critical pro-inflammatory cytokines in the drive of cytokine storm during SARS-CoV-2 infection

In patients with severe COVID-19, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), and even mortality can result from cytokine storm, which is a hyperinflammatory medical condition caused by the excessive and uncontrolled release of pro-inflammatory cytokines. High levels of numerous crucial pro-inflammatory cytokines, such as interleukin-1 (IL-1), IL-2, IL-6, tumor necrosis factor-α, interferon (IFN)-γ, IFN-induced protein 10 kDa, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein-1, and IL-10 and so on, have been found in severe COVID-19. They participate in cascade amplification pathways of pro-inflammatory responses through complex inflammatory networks. Here, we review the involvements of these critical inflammatory cytokines in SARS-CoV-2 infection and discuss their potential roles in triggering or regulating cytokine storm, which can help to understand the pathogenesis of severe COVID-19. So far, there is rarely effective therapeutic strategy for patients with cytokine storm besides using glucocorticoids, which is proved to result in fatal side effects. Clarifying the roles of key involved cytokines in the complex inflammatory network of cytokine storm will help to develop an ideal therapeutic intervention, such as neutralizing antibody of certain cytokine or inhibitor of some inflammatory signal pathways.

Protective assessment of progesterone and its receptor on experimental diabetic neuropathy: Antioxidant and anti-inflammatory effects

Diabetes induces a disorder in mitochondrial activity, which causes damage to the nuclear and mitochondrial DNA and ultimately increases the release of inflammatory cytokines and damages the sciatic nerve and dorsal root ganglion and induces neuropathy. It has been shown that progesterone has anti-inflammatory and antioxidative effects and prevents nerve cell damage. Therefore, the aim of this experiment was to investigate the effect of progesterone receptor neuroprotection on diabetic neuropathy. Forty male Sprague-Dawley rats were divided into four groups, including control group, diabetic control group, diabetic control group + progesterone (30 mg/kg), and diabetic control group + combination of progesterone (30 mg/kg) and RU486 (10 mg/kg). After the induction of diabetes, blood glucose level, body weight, behavioral tests, electrophysiological tests, oxidative and inflammatory factors, and histological parameters were measured. Progesterone treatment significantly reduced the level of sensitivity to hot plate without significant effect on glucose level, and significant changes were also observed in the results of tail flick test. In addition, the results showed that the administration of progesterone can improve MNCV and significantly reduce the serum levels of oxidative stress and inflammatory factors, as well as inflammation and edema around the sciatic nerve. However, RU486 inverted the beneficial effects of progesterone. Progesterone can be considered as a protective agent in reducing DN because of its ability to reduce inflammation and nerve damage. In addition, RU486, a progesterone receptor blocker, inhibits the beneficial effects of progesterone on the DN; thus, progesterone receptors play an important role in the neuroprotective effect of progesterone.

One messenger shared by two systems: How cytokines directly modulate neurons

Cytokines are small, secreted proteins that are known for their roles in the immune system. An accumulating body of evidence indicates that cytokines also work as neuromodulators in the central nervous system (CNS). Cytokines can access the CNS through multiple routes to directly impact neurons. The neuromodulatory effects of cytokines maintain the overall homeostasis of neural networks. In addition, cytokines regulate a diverse repertoire of behaviors both at a steady state and in inflammatory conditions by acting on discrete brain regions and neural networks. In this review, we discuss recent findings that provide insight into how combinatorial codes of cytokines might mediate neuro-immune communications to orchestrate functional responses of the brain to changes in immunological milieus.

BIOMARKERS: CAN THEY REALLY GUIDE OUR DAILY PRACTICE?

ABSTRACT

Optimal management of septic patients requires accurate assessment of both current severity status and prognosis. Since the 1990s, substantial advances have been made in the use of circulating biomarkers for such assessments. This summary of the session on "Biomarkers: can they really use guide our daily practice?" presented at the 2021 WEB-CONFERENCE OF THE EUROPEAN SHOCK SOCIETY, 6 November 2021. These biomarkers include ultrasensitive detection of bacteremia, circulating soluble urokina-type plasminogen activator receptor (suPAR), C-reactive protein (CRP) and ferritin and procalcitonin. In addition, the potential application of novel multiwavelength optical biosensor technology allows noninvasive monitoring of multiple metabolites that can be used to assess severity and prognosis in septic patients. The application these biomarkers and improved technologies provide the potential for improved personalized management of septic patients.

Prognostic Impact of C-Reactive Protein-to-Lymphocyte Ratio in Non-small Cell Lung Cancer: A Propensity Score-Matching Analysis

BACKGROUND

Many inflammatory and nutritional markers have been used to predict prognosis in lung cancer. The C-reactive protein (CRP)-to-lymphocyte ratio (CLR) is a useful prognostic factor in various cancers. However, the prognostic value of preoperative CLR in patients with non-small cell lung cancer (NSCLC) remains to be established. We examined the significance of the CLR compared with known markers.

METHODS

A total of 1380 surgically resected NSCLC patients treated at two centers were recruited and divided into derivation and validation cohorts. After CLRs were calculated, patients were classified into high and low CLR groups based on the cutoff value determined by receiver operating characteristics curve analysis. Subsequently, we determined the statistical associations of the CLR with clinicopathological factors and prognosis and further analyzed its prognostic impact by propensity-score matching.

RESULTS

Of all the inflammatory markers examined, CLR yielded the highest area-under-the-curve value. The prognostic impact of CLR remained significant after propensity-score matching. Prognosis was significantly worse in the high-CLR group than in the low-CLR group (5-year, disease-free survival [DFS]: 58.1% vs. 81.9%, P < 0.001; 5-year overall survival [OS]: 72.1% vs. 91.2%, P < 0.001). The results were confirmed in the validation cohorts. Multivariable analysis also showed high CLR as an independent factor for both DFS and OS (DFS: hazard ratio [HR] 1.42, P = 0.027; OS: HR 1.95, P = 0.0037).

CONCLUSIONS

Preoperative CLR is a useful marker for predicting the prognosis of NSCLC patients who have undergone surgery.

Elevated free interleukin-18 associated with severity and mortality in prospective cohort study of 206 hospitalised COVID-19 patients

BACKGROUND

Divergence between deterioration to life-threatening COVID-19 or clinical improvement occurs for most within the first 14 days of symptoms. Life-threatening COVID-19 shares clinical similarities with Macrophage Activation Syndrome, which can be driven by elevated Free Interleukin-18 (IL-18) due to failure of negative-feedback release of IL-18 binding protein (IL-18bp). We, therefore, designed a prospective, longitudinal cohort study to examine IL-18 negative-feedback control in relation to COVID-19 severity and mortality from symptom day 15 onwards.

METHODS

662 blood samples, matched to time from symptom onset, from 206 COVID-19 patients were analysed by enzyme-linked immunosorbent assay for IL-18 and IL-18bp, enabling calculation of free IL-18 (fIL-18) using the updated dissociation constant (K_d) of 0.05 nmol. Adjusted multivariate regression analysis was used to assess the relationship between highest fIL-18 and outcome measures of COVID-19 severity and mortality. Re-calculated fIL-18 values from a previously studied healthy cohort are also presented.

RESULTS

Range of fIL-18 in COVID-19 cohort was 10.05-1157.7 pg/ml. Up to symptom day 14, mean fIL-18 levels increased in all patients. Levels in survivors declined thereafter, but remained elevated in non-survivors. Adjusted regression analysis from symptom day 15 onwards showed a 100 mmHg decrease in PaO₂/FiO₂ (primary outcome) for each 37.7 pg/ml increase in highest fIL-18 (p < 0.03). Per 50 pg/ml increase in highest fIL-18, adjusted logistic regression gave an odds-ratio (OR) for crude 60-day mortality of 1.41 (1.1-2.0) (p < 0.03), and an OR for death with hypoxaemic respiratory failure of 1.90 [1.3-3.1] (p < 0.01). Highest fIL-18 was associated also with organ failure in patients with hypoxaemic respiratory failure, with an increase of 63.67 pg/ml for every additional organ supported (p < 0.01).

CONCLUSIONS

Elevated free IL-18 levels from symptom day 15 onwards are associated with COVID-19 severity and mortality. ISRCTN: #13450549; registration date: 30/12/2020.

Evaluation of the Diagnostic Performance of Plasma Metagenomic Next-Generation Sequencing in Febrile Events in the First 30 Days after Chimeric Antigen Receptor T Cell Infusion

Chimeric antigen receptor-modified T cell (CAR-T) therapy is a promising novel immunotherapy for hematologic malignancies, and the diagnosis of infection after CAR-T infusion (CTI) presents challenges for clinicians. Plasma metagenomic next-generation sequencing (mNGS) has been shown to be a reliable diagnostic approach for infection, especially in immunocompromised patients. We aimed to investigate the diagnostic performance of plasma mNGS for infection in the first 30 days after CTI. A cohort of 153 patients who experienced a total of 170 febrile events during the first 30 days post-CTI were enrolled. Of these events, 51 were evaluated with both mNGS and CDM and 119 were assessed by conventional detection methods (CDM) only. We also explored the epidemiology of infections and differences in infection complications in cases with severe (>2) and moderate (≤2) cytokine release syndrome (CRS). Cases with febrile events were clinically divided into an infection group (IG) (95 of 170; 55.9%) and a noninfection group (NIG) (75 of 170; 44.1%). The sensitivity and specificity of mNGS for the diagnosis of infectious complications in the first 30 days after CTI were 69.2% and 89.2%, respectively, with the sensitivity superior to that of culture (P < .001). More infection cases assessed with both mNGS and CDM than those assessed with CDM only were laboratory-confirmed (63.9% versus 11.9%; P < .001). The serum C-reactive protein level was higher and the IFN-γ level was lower in the IG group, particularly in cases with CRS grade ≤2. Infection is a common complication in the first 30 days after CTI. The addition of mNGS to CDM improved the diagnostic yield, and mNGS showed relatively high sensitivity and specificity in post-CAR-T therapy febrile events.

A cross-sectional study of inflammatory markers as determinants of circulating kynurenines in the Lung Cancer Cohort Consortium

Circulating concentrations of metabolites (collectively called kynurenines) in the kynurenine pathway of tryptophan metabolism increase during inflammation, particularly in response to interferon-gamma (IFN-γ). Neopterin and the kynurenine/tryptophan ratio (KTR) are IFN-γ induced inflammatory markers, and together with C-reactive protein (CRP) and kynurenines they are associated with various diseases, but comprehensive data on the strength of associations of inflammatory markers with circulating concentrations of kynurenines are lacking. We measured circulating concentrations of neopterin, CRP, tryptophan and seven kynurenines in 5314 controls from 20 cohorts in the Lung Cancer Cohort Consortium (LC3). The associations of neopterin, KTR and CRP with kynurenines were investigated using regression models. In mixed models, one standard deviation (SD) higher KTR was associated with a 0.46 SD higher quinolinic acid (QA), and 0.31 SD higher 3-hydroxykynurenine (HK). One SD higher neopterin was associated with 0.48, 0.44, 0.36 and 0.28 SD higher KTR, QA, kynurenine and HK, respectively. KTR and neopterin respectively explained 24.1% and 16.7% of the variation in QA, and 11.4% and 7.5% of HK. CRP was only weakly associated with kynurenines in regression models. In summary, QA was the metabolite that was most strongly associated with the inflammatory markers. In general, the inflammatory markers were most strongly related to metabolites located along the tryptophan-NAD axis, which may support suggestions of increased production of NAD from tryptophan during inflammation.

Utility of High-Sensitivity Modified Glasgow Prognostic Score in Cancer Prognosis: A Systemic Review and Meta-Analysis

The suitability of the high-sensitivity modified Glasgow Prognostic Score (HS-mGPS) in cancer patients remains unknown. We performed a systematic database search from 1 January 2010 to 30 September 2022, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Selected studies reported the HS-mGPS and survival outcomes in cancer patients. The association between the HS-mGPS and survival outcomes was evaluated using a random-effects model and expressed as pooled hazard ratios (HRs) with 95% CIs. This meta-analysis evaluated 17 studies with a total of 5828 cancer patients. A higher HS-mGPS was found to be associated with an adverse OS (HR = 2.17; 95% CI: 1.80-2.60), DSS (HR = 3.81; 95% CI: 2.03-7.17), and DFS (HR = 1.96; 95% CI: 1.48-2.58; all p ≤ 0.001). The prognostic value of the HS-mGPS for the OS trended in a consistent direction after subgrouping and sensitivity analysis. In conclusion, the HS-mGPS serves as a valid prognostic biomarker for cancer patients, with a high HS-mGPS associated with adverse survival outcomes.

Characterization of the innate immune response to Streptococcus pneumoniae infection in zebrafish

Streptococcus pneumoniae (pneumococcus) is one of the most frequent causes of pneumonia, sepsis and meningitis in humans, and an important cause of mortality among children and the elderly. We have previously reported the suitability of the zebrafish (Danio rerio) larval model for the study of the host-pathogen interactions in pneumococcal infection. In the present study, we characterized the zebrafish innate immune response to pneumococcus in detail through a whole-genome level transcriptome analysis and revealed a well-conserved response to this human pathogen in challenged larvae. In addition, to gain understanding of the genetic factors associated with the increased risk for severe pneumococcal infection in humans, we carried out a medium-scale forward genetic screen in zebrafish. In the screen, we identified a mutant fish line which showed compromised resistance to pneumococcus in the septic larval infection model. The transcriptome analysis of the mutant zebrafish larvae revealed deficient expression of a gene homologous for human C-reactive protein (CRP). Furthermore, knockout of one of the six zebrafish crp genes by CRISPR-Cas9 mutagenesis predisposed zebrafish larvae to a more severe pneumococcal infection, and the phenotype was further augmented by concomitant knockdown of a gene for another Crp isoform. This suggests a conserved function of C-reactive protein in anti-pneumococcal immunity in zebrafish. Altogether, this study highlights the similarity of the host response to pneumococcus in zebrafish and humans, gives evidence of the conserved role of C-reactive protein in the defense against pneumococcus, and suggests novel host genes associated with pneumococcal infection.