Cytokine Signature of Dengue Patients at Different Severity of the Disease

Dengue NS1 interaction with lipids alters its pathogenic effects on monocyte derived macrophages

Background

While dengue NS1 antigen has been shown to be associated with disease pathogenesis in some studies, it has not been linked in other studies, with the reasons remaining unclear. NS1 antigen levels in acute dengue are often associated with increased disease severity, but there have been a wide variation in results based on past dengue infection and infecting dengue virus (DENV) serotype. As NS1 engages with many host lipids, we hypothesize that the type of NS1-lipid interactions alters its pathogenicity.

Methods

Primary human monocyte derived macrophages (MDMs) were co-cultured with NS1 alone or with HDL, LDL, LPS and/or platelet activating factor (PAF) from individuals with a history of past dengue fever (DF=8) or dengue haemorrhagic fever (DHF=8). IL-1β levels were measured in culture supernatants, and gene expression analysis carried out in MDMs. Monocyte subpopulations were assessed by flow cytometry. Hierarchical cluster analysis with Euclidean distance calculations were used to differentiate clusters. Differentially expressed variables were extracted and a classifier model was developed to differentiate between past DF and DHF.

Results

Significantly higher levels of IL-1β were seen in culture supernatants when NS1 was co-cultured with LDL (p=0.01), but with lower levels with HDL (p=0.05). MDMs of those past DHF produced more IL-1β when NS1 with PAF (p=0.02). MDMs of individuals with past DHF, were significantly more likely to down-regulate RPLP2 gene expression when macrophages were co-cultured with either PAF alone, or NS1 combined with PAF, or NS1 combined with LDL. When NS1 was co-cultured with PAF, HDL or LDL two clusters were detected based on IL10 expression, but these did not differentiate those with past DF or DHF.

Conclusions

As RPLP2 is important in DENV replication and in regulating cellular stress responses and immune responses and IL-10 is associated with severe disease, it would be important to further explore how differential expression of RPLP2 and IL-10 could lead to disease pathogenesis based on NS1 and lipid interactions.

The Dynamic Relationship between Dengue Virus and the Human Cutaneous Innate Immune Response

Dengue virus (DENV) is a continuing global threat that puts half of the world's population at risk for infection. This mosquito-transmitted virus is endemic in over 100 countries. When a mosquito takes a bloodmeal, virus is deposited into the epidermal and dermal layers of human skin, infecting a variety of permissive cells, including keratinocytes, Langerhans cells, macrophages, dermal dendritic cells, fibroblasts, and mast cells. In response to infection, the skin deploys an array of defense mechanisms to inhibit viral replication and prevent dissemination. Antimicrobial peptides, pattern recognition receptors, and cytokines induce a signaling cascade to increase transcription and translation of pro-inflammatory and antiviral genes. Paradoxically, this inflammatory environment recruits skin-resident mononuclear cells that become infected and migrate out of the skin, spreading virus throughout the host. The details of the viral-host interactions in the cutaneous microenvironment remain unclear, partly due to the limited body of research focusing on DENV in human skin. This review will summarize the functional role of human skin, the cutaneous innate immune response to DENV, the contribution of the arthropod vector, and the models used to study DENV interactions in the cutaneous environment.

Pro- and anti-inflammatory cytokines signatures at different severity of dengue infection

Context

Dengue disease severity and progression are determined by the host immune response, with both pro- and anti-inflammatory cytokines are key mediators.

Aims

To study pro- and anti-inflammatory cytokines across dengue severity and as a biomarker for predicting severe dengue infection.

Settings and Design

Hospital-based cross-sectional study was conducted on 125 dengue-positive subjects across the 5-60 years age group of either gender in 2022.

Methods and Materials

Haematological parameters and blood samples were drawn to measure cytokines IL6, IL-10 and TNF alpha using the ELISA technique.

Statistical Analysis

One-way ANOVA and the Kruskal - Wallis test were used to compare the dependent variables across categories of the dengue spectrum. Receiver operating characteristic curve was drawn to calculate the predictability of the cytokines as a predictor of severe dengue. A P < 0.05 was considered significant.

Results

34.4% of cases had severe dengue infection with 53.2% of severe cases reported in >40 years of age. Only IL-6 levels significantly increased (P < 0.01) across the spectrum of dengue infection across age groups >20 years with a consistent and significant fall in platelet levels (P < 0.01). The accuracy of IL-6 to predict severe dengue was 74.4% and platelet count was 16.2%.

Conclusions

Only IL-6 cytokine levels were significantly increased across the spectrum of dengue infection observed in age >20 years and can significantly predict the probability of severe dengue by 74% (sensitivity 81.4%). A significant decrease in platelet values is consistent with the severity but is not a good predictor for severe dengue infection.

Cytokine profiles in dengue fever and dengue hemorrhagic fever: A study from Indonesia

Recent studies have demonstrated that cytokine dysregulation has a critical role in the pathogenesis of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The aim of this study was to investigate the association between tumor necrosis factor (TNF- α), interleukin 6 (IL-6), interleukin 10 (IL-10), and interleukin 17 (IL-17) with infection status, and severity of dengue. A prospective cross-sectional study was conducted at three hospitals in Gianyar regency and Denpasar municipality, Bali, Indonesia, from June to December 2022. Sixty-four dengue infected patients were involved. Patients' serum was tested for dengue infection using NS1 antigen rapid test, dengue virus immunoglobulin M (IgM) and immunoglobulin G (IgG) test, and reverse transcription polymerase chain reaction (RT-PCR). Cytokine levels (TNF-α, IL-6, IL-10, and IL-17) were measured using enzyme-linked immunosorbent assay (ELISA). Infection status was determined by combining serological and RT-PCR results, categorizing patients into primary and secondary infections. The present study found that DF patients had lower TNF-α, IL-6, and IL-17 but higher IL-10 levels compared to DHF patients (p<0.001). Elevated TNF-α, IL-6, and IL-17 levels were higher in secondary infection, while IL-10 level was higher in primary infection (p<0.001). In conclusion, cytokines play a crucial role in the interplay between cytokine dysregulation and dengue infection dynamics.

Extracellular vesicles recovered from plasma of severe dengue patients induce CD4+ T cell suppression through PD-L1/PD-1 interaction

IMPORTANCE

Severe dengue manifestations caused by the dengue virus are a global health problem. Studies suggest that severe dengue disease depends on uncontrolled immune cell activation, and excessive inflammation adds to the pathogenesis of severe dengue disease. Therefore, it is important to understand the process that triggers the uncontrolled activation of the immune cells. The change in immune response in mild to severe dengue may be due to direct virus-to-cell interaction or it could be a contact-independent process through the extracellular vesicles (EVs) released from infected cells. The importance of circulating EVs in the context of dengue virus infection and pathogenesis remains unexplored. Therefore, understanding the possible biological function of circulating EVs may help to delineate the role of EVs in the progression of disease. Our present study highlights that EVs from plasma of severe dengue patients can have immunosuppressive properties on CD4+ T cells which may contribute to T cell suppression and may contribute to dengue disease progression.

Viremia and Inflammatory Cytokines in Dengue: Interleukin-2 as a Biomarker of Infection, and Interferon-α and -γ as Markers of Primary versus Secondary Infection

The pathogenesis of Dengue virus (DENV) infection is complex and involves viral replication that may trigger an inflammatory response leading to severe disease. Here, we investigated the correlation between viremia and cytokine levels in the serum of DENV-infected patients. Between 2013 and 2014, 138 patients with a diagnosis of acute-phase DENV infection and 22 patients with a non-dengue acute febrile illness (AFI) were enrolled. Through a focus-forming assay (FFU), we determined the viremia levels in DENV-infected patients and observed a peak in the first two days after the onset of symptoms. A higher level of viremia was observed in primary versus secondary DENV-infected patients. Furthermore, no correlation was observed between viremia and inflammatory cytokine levels in DENV-infected patients. Receiver operating characteristic (ROC) curve analysis revealed that IL-2 has the potential to act as a marker to distinguish dengue from other febrile illnesses and is positively correlated with Th1 cytokines. IFN-α and IFN-γ appear to be potential markers of primary versus secondary infection in DENV-infected patients, respectively. The results also indicate that viremia levels are not the main driving force behind inflammation in dengue and that cytokines could be used as infection biomarkers and for differentiation between primary versus secondary infection.

A combination of burn wound injury and Pseudomonas infection elicits unique gene expression that enhances bacterial pathogenicity

Burns are a leading cause of morbidity and mortality worldwide with the most common cause of death resulting from sepsis, often from Pseudomonas aeruginosa. We previously reported that a non-lethal flame burn induced an altered host immune response. Using this model, gene expression in both the murine host and P. aeruginosa was measured using a NanoString custom probe panel. We observed differing patterns of gene expression in both host and P. aeruginosa in the skin, blood, liver, and spleen of mice that were burned and/or infected, compared to mice that were neither burned nor infected (i.e., Sham). In mice that were both burned and infected (B/I), we observed changes in gene expression in both the host and P. aeruginosa that were distinct from all other treatment conditions. These data suggest that the combination of the burned state and superimposed infection affects both host and pathogen gene expression to increase infection propensity. Gene transcription significantly changed from 6 to 24 h post-B/I in each tissue. Finally, inhibiting IL-10 signaling or co-administering arginine at the time of P. aeruginosa infection prolonged or restored survival in an otherwise 100% fatal burn and infection model. These findings suggest that disease states such as burns may differentially alter innate immune response gene expression in both a host- and pathogen-specific manner.IMPORTANCEThe interaction between an underlying disease process and a specific pathogen may lead to the unique expression of genes that affect bacterial pathogenesis. These genes may not be observed during infection in the absence of, or with a different underlying process or infection during the underlying process with a different pathogen. To test this hypothesis, we used Nanostring technology to compare gene transcription in a murine-burned wound infected with P. aeruginosa. The Nanostring probeset allowed the simultaneous direct comparison of immune response gene expression in both multiple host tissues and P. aeruginosa in conditions of burn alone, infection alone, and burn with infection. While RNA-Seq is used to discover novel transcripts, NanoString could be a technique to monitor specific changes in transcriptomes between samples and bypass the additional adjustments for multispecies sample processing or the need for the additional steps of alignment and assembly required for RNASeq. Using Nanostring, we identified arginine and IL-10 as important contributors to the lethal outcome of burned mice infected with P. aeruginosa. While other examples of altered gene transcription are in the literature, our study suggests that a more systematic comparison of gene expression in various underlying diseases during infection with specific bacterial pathogens may lead to the identification of unique host-pathogen interactions and result in more precise therapeutic interventions.

Impact of apoptotic biomarkers for prognosis of dengue disease severity among eastern Indian patients

Dengue virus (DENV) induced severe manifestations is a precursor for fatality among infected patients. Previous autopsy examinations of severe dengue (SD) patients reported presence of apoptotic cells in liver, brain, intestinal and lung tissues. Thus, serum-level of major apoptotic proteins of dengue patients was evaluated in the current study, along with their biochemical parameters. Patients were categorized according to World Health Organization (WHO)-defined classification. DENV-infection was screened among 165 symptomatic patients by quantitative reverse transcription polymerase chain reaction, antidengue IgM, and IgG ELISA. Serum levels of apoptotic (Capase-3,7,8, Bcl-2 and FasL) and hepatic-markers, lipid profile, hematological parameters of 78 dengue-positive patients were determined by sandwich-ELISA/immunoturbidimetry/auto-analyzer. Significantly higher levels of caspase-3,7,8 and FasL was detected among SD patients compared to those without warning (WOW) signs. Amongst biochemical parameters, bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase serum concentrations significantly increased among severe patients. Principal component analysis followed by hierarchical clustering differentiated severe and with warning dengue patient groups from those WOW using caspase-3,7,8 and FasL biomarkers-thus clearly distinguishing severe-dengue group. Correlation analyses also established strong positive correlation between caspase-3,7,8 and FasL. Thus, serum level of caspase-3,7,8 and FasL during early stage of infection could be used as biomarkers for WHO-defined dengue disease severity.

Dengue overview: An updated systemic review

Dengue is caused by the dengue virus (DENVs) infection and clinical manifestations include dengue fever (DF), dengue hemorrhagic fever (DHF), or dengue shock syndrome (DSS). Due to a lack of antiviral drugs and effective vaccines, several therapeutic and control strategies have been proposed. A systemic literature review was conducted according to PRISMA guidelines to select proper references to give an overview of DENV infection. Results indicate that understanding the virus characteristics and epidemiology are essential to gain the basic and clinical knowledge as well as dengue disseminated pattern and status. Different factors and mechanisms are thought to be involved in the presentation of DHF and DSS, including antibody-dependent enhancement, immune dysregulation, viral virulence, host genetic susceptibility, and preexisting dengue antibodies. This study suggests that dissecting pathogenesis and risk factors as well as developing different types of therapeutic and control strategies against DENV infection are urgently needed.

Genetic polymorphisms rs1800871 and rs1800872 of IL-10 gene are associated with dengue infection, especially with serotype 1 and DwoWS in Mexican population

INTRODUCTION

Dengue infection is generated by a complex interaction between DENV (Dengue Virus) and the host's immune response. Interleukin-10 is an immunoregulatory cytokine during DENV infection. The objective of this study was to investigate whether genetic variants in IL-10 could be useful as a predictive and susceptibility marker in the prognosis of DENV infection, particularly with serotype 1, and in participants with dengue without warning signs.

MATERIAL AND METHODS

A study of cases (n = 365) and controls (n = 364) was carried out. Genotyping was performed by real-time PCR using TaqMan probes. Sample size power was calculated using Quanto software RESULTS: This is the first report showing the independent association of the T allele of rs1800871 (P = 0.023) and the A allele of rs1800872 (P = 0.010) with the risk of dengue infection. Statistical analysis established the genotypic association of IL-10 SNPs with DENV infection under different inheritance models. Our results also showed the association of the CC, TC, and CA haplotypes (P = 0.0064, P = 0.0032, and P = 0.0010 respectively) with infection. Furthermore, both polymorphic sites were associated with the risk of DwoWS and serotype 1 (Den-1) under different inheritance models. Finally, under the dominant model, we identified a positive correlation between IL-10 levels vs. IFN-γ and IL-8.

CONCLUSION

Our results show the first independent association of the T and A alleles of the polymorphic sites rs1800871 and rs1800872, with dengue infection, particularly with Den-1, and in participants with DwoWs.

Simulation of Hemorrhage Pathogenesis in Mice through Dual Stimulation with Dengue Envelope Protein Domain III-Coated Nanoparticles and Antiplatelet Antibody

Dengue hemorrhagic fever (DHF) is a severe form of dengue virus (DENV) infection that can lead to abnormal immune responses, endothelial vascular dysfunction, and hemorrhage pathogenesis. The virion-associated envelope protein domain III (EIII) is thought to play a role in the virulence of DENV by damaging endothelial cells. However, it is unclear whether EIII-coated nanoparticles simulating DENV virus particles could cause a more severe pathogenesis than soluble EIII alone. This study aimed to investigate whether EIII-coated silica nanoparticles (EIII-SNPs) could elicit greater cytotoxicity in endothelial cells and hemorrhage pathogenesis in mice compared to EIII or silica nanoparticles alone. The main methods included in vitro assays to assess cytotoxicity and in vivo experiments to examine hemorrhage pathogenesis in mice. EIII-SNPs induced greater endothelial cytotoxicity in vitro than EIII or silica nanoparticles alone. Two-hit combined treatment with EIII-SNPs and antiplatelet antibodies to simulate DHF hemorrhage pathogenesis during secondary DENV infections resulted in higher endothelial cytotoxicity than either treatment alone. In mouse experiments, two-hit combined treatment with EIII-SNPs and antiplatelet antibodies resulted in more severe hemorrhage pathogenesis compared to single treatments of EIII, EIII-SNPs, or antiplatelet antibodies alone. These findings suggest that EIII-coated nanoparticles are more cytotoxic than soluble EIII and could be used to develop a tentative dengue two-hit hemorrhage pathogenesis model in mice. Additionally, our results indicated that EIII-containing DENV particles could potentially exacerbate hemorrhage pathogenesis in DHF patients who have antiplatelet antibodies, highlighting the need for further research on the potential role of EIII in DHF pathogenesis.

Detection of Anti-ZIKV NS1 IgA, IgM, and Combined IgA/IgM and Identification of IL-4 and IL-10 as Potential Biomarkers for Early ZIKV and DENV Infections in Hyperendemic Regions, Thailand

The frequency of Zika virus (ZIKV)-specific IgA and IgM and the cytokine expression profile of ZIKV-infected patients in hyperendemic areas remain unclear. This study investigated the rates of ZIKV non-structural protein 1 (NS1)-specific IgA and IgM and evaluated serum cytokine levels of ZIKV and Dengue virus (DENV) cases in Thailand to identify potential diagnostic biomarkers, elucidate the immunity against ZIKV and DENV, and investigate the association between cytokine levels and ZIKV symptoms. Low rates of positivity for ZIKV NS1-specific IgA and IgM were detected in our study. ZIKV NS1 IgA/M (11%, 11/101) in combination was more frequently detected than ZIKV NS1 IgM (2%, 2/101) or ZIKV NS1 IgA (4%, 4/96) alone, especially in acute ZIKV cases with previous DENV exposure (14%, 10/72). Cytokine analysis showed that both ZIKV and DENV infections induced polyfunctional immunity, and the latter triggered more prolonged responses. The existence of significant differences in IL-4 and IL-10 levels between acute ZIKV and acute DENV cases suggested that IL-4 (p = 0.0176) and IL-10 (p = 0.0003) may represent biomarkers for acute ZIKV and acute DENV infections, respectively. Analysis of the association between increased cytokine levels and ZIKV symptoms indicated that CXCL10 (p = 0.0029) was associated with exanthema, while IL-5 (p = 0.0496) was linked to headache. The detection of ZIKV NS1 IgA and IgM in combination may enhance the diagnosis of early ZIKV infection, particularly when levels of IgM or IgA alone are low or undetectable. IL-4 and IL-10 may serve as targets for the development of diagnostic tools to detect ZIKV and DENV infections early, respectively, in flavivirus-endemic regions.

Assessing the potential of NS2B/NS3 protease inhibitors biomarker in curbing dengue virus infections: In silico vs. In vitro approach

An increase in the occurrence of viral infectious diseases is a global concern for human health. According to a WHO report, dengue virus (DENV) is one of the most common viral diseases affecting approximately 400 million people annually, with worsening symptoms in nearly 1% of cases. Both academic and industrial researchers have conducted numerous studies on viral epidemiology, virus structure and function, source and route of infection, treatment targets, vaccines, and drugs. The development of CYD-TDV or Dengvaxia^® vaccine has been a major milestone in dengue treatment. However, evidence has shown that vaccines have some drawbacks and limitations. Therefore, researchers are developing dengue antivirals to curb infections. DENV NS2B/NS3 protease is a DENV enzyme essential for replication and virus assembly, making it an interesting antiviral target. For faster hit and lead recognition of DENV targets, methods to screen large number of molecules at lower costs are essential. Similarly, an integrated and multidisciplinary approach involving in silico screening and confirmation of biological activity is required. In this review, we discuss recent strategies for searching for novel DENV NS2B/NS3 protease inhibitors from the in silico and in vitro perspectives, either by applying one of the approaches or by integrating both. Therefore, we hope that our review will encourage researchers to integrate the best strategies and encourage further developments in this area.

Longitudinal proteomic profiling of the inflammatory response in dengue patients

BACKGROUND

The immunopathogenesis of dengue virus (DENV) infection remains incompletely understood. To increase our understanding of inflammatory response in non-severe dengue, we assessed longitudinal changes in the inflammatory proteome in patients with an acute DENV infection.

METHODS

Using a multiplex proximity extension assay (PEA), we measured relative levels of 368 inflammatory markers in plasma samples from hospitalized patients with non-severe DENV infection in the acute (n = 43) and convalescence (n = 35) phase of the infection and samples of healthy controls (n = 10).

RESULTS

We identified 203 upregulated and 39 downregulated proteins in acute versus convalescent plasma samples. The upregulated proteins had a strong representation of interferon (IFN) and IFN-inducible effector proteins, cytokines (e.g. IL-10, IL-33) and cytokine receptors, chemokines, pro-apoptotic proteins (e.g. granzymes) and endothelial markers. A number of differentially expressed proteins (DEPs) have not been reported in previous studies. Functional network analysis highlighted a central role for IFNγ, IL-10, IL-33 and chemokines. We identified different novel associations between inflammatory proteins and circulating concentrations of the endothelial glycocalyx disruption surrogate marker syndecan-1. Conclusion: This unbiased proteome analysis provides a comprehensive insight in the inflammatory response in DENV infection and its association with glycocalyx disruption.

Immune-Mediated Pathogenesis in Dengue Virus Infection

Dengue virus (DENV) infection is one of the major public health concerns around the globe, especially in the tropical regions of the world that contribute to 75% percent of dengue cases. While the majority of DENV infections are mild or asymptomatic, approximately 5% of the cases develop a severe form of the disease that is mainly attributed to sequential infection with different DENV serotypes. The severity of dengue depends on many immunopathogenic mechanisms involving both viral and host factors. Emerging evidence implicates an impaired immune response as contributing to disease progression and severity by restricting viral clearance and inducing severe inflammation, subsequently leading to dengue hemorrhagic fever and dengue shock syndrome. Moreover, the ability of DENV to infect a wide variety of immune cells, including monocytes, macrophages, dendritic cells, mast cells, and T and B cells, further dysregulates the antiviral functions of these cells, resulting in viral dissemination. Although several risk factors associated with disease progression have been proposed, gaps persist in the understanding of the disease pathogenesis and further investigations are warranted. In this review, we discuss known mechanisms of DENV-mediated immunopathogenesis and its association with disease progression and severity.

Mobilization of Hematopoietic Stem and Progenitor Cells during Dengue Virus Infection

Hematopoietic stem and progenitor cells (HSPCs) mobilization is the movement of HSPCs from the bone marrow to the peripheral blood or tissue induced by stress. HSPC mobilization is a well-known response to protect the host during infection through urgent differentiation of HSPCs to immune cells. Dengue virus (DENV) infection is known to cause stress in infected humans and the mobilizing capacity of HSPCs during DENV infection in affected patients has not been fully investigated. Here, we investigated whether DENV infection can induce HSPC mobilization and if the mobilized HSPCs are permissive to DENV infection. White blood cells (WBCs) were collected from dengue patients (DENV+) and healthy donors and analyzed by flow cytometry and plaque assay. Elevated HSPCs levels were found in the WBCs of the DENV+ group when compared to the healthy group. Mobilization of HSPCs and homing markers (skin and gut) expression decreased as the patients proceeded from dengue without symptoms (DWoWS) to severe dengue (SD). Mobilizing HSPCs were not only permissive to DENV infection, but infectious DENV could be recovered after coculture. Our results highlight the need for further investigation into HSPC mobilization or alterations of hematopoiesis during viral infections such as DENV in order to develop appropriate countermeasures.

The Role of Growth Factors in the Pathogenesis of Dengue: A Scoping Review

Growth factors (GFs) have a role in tissue repair and in the modulation of the expression of inflammatory cells in damage caused by pathogens. This study aims to systematize the evidence on the role of GFs in the pathogenesis of dengue. This scoping review considered all published peer-reviewed studies in the MEDLINE and Embase databases. Ultimately, 58 studies that analyzed GFs in dengue patients, published between 1998 and 2021, were included. DENV-2 infection and secondary infection were more frequent in the patients studied. ELISA and multiplex immunoassay (Luminex) were the most used measurement techniques. Increased levels of vascular endothelial growth factor, granulocyte–macrophage colony-stimulating factor, granulocyte colony-stimulating factor, transforming growth factor beta, and hepatocyte growth factor as well as reduced levels of platelet-derived growth factor and epidermal growth factor were observed in severe dengue in most studies. Vascular endothelial growth factor and hepatocyte growth factor were identified as biomarkers of severity. In addition, there is evidence that the dengue virus can use the growth factor pathway to facilitate its entry into the cell and promote its viral replication. The use of tyrosine kinase inhibitors is an alternative treatment for dengue that is being studied.

Antrodia cinnamomea Suppress Dengue Virus Infection through Enhancing the Secretion of Interferon-Alpha

Dengue caused by dengue virus (DENV) is a mosquito-borne disease. Dengue exhibits a wide range of symptoms, ranging from asymptomatic to flu-like illness, and a few symptomatic cases may develop into severe dengue, leading to death. However, there are no effective and safe therapeutics for DENV infections. We have previously reported that cytokine expression, especially inflammatory cytokines, was altered in patients with different severities of dengue. Antrodia cinnamomea (A. cinnamomea) is a precious and endemic medical mushroom in Taiwan. It contains unique chemical components and exhibits biological activities, including suppressing effects on inflammation and viral infection-related diseases. According to previous studies, megakaryocytes can support DENV infection, and the number of megakaryocytes is positively correlated with the viral load in the serum of acute dengue patients. In the study, we investigated the anti-DENV effects of two ethanolic extracts (ACEs 1-2) and three isolated compounds (ACEs 3-5) from A. cinnamomea on DENV infection in Meg-01 cells. Our results not only demonstrated that ACE-3 and ACE-4 significantly suppressed DENV infection, but also reduced interleukin (IL)-6 and IL-8 levels. Moreover, the level of the antiviral cytokine interferon (IFN)-α was also increased by ACE-3 and ACE-4 in Meg-01 cells after DENV infection. Here, we provide new insights into the potential use of A. cinnamomea extracts as therapeutic agents against DENV infection. However, the detailed mechanisms underlying these processes require further investigation.

Endothelial Dysfunction, HMGB1, and Dengue: An Enigma to Solve

Dengue is a viral infection caused by dengue virus (DENV), which has a significant impact on public health worldwide. Although most infections are asymptomatic, a series of severe clinical manifestations such as hemorrhage and plasma leakage can occur during the severe presentation of the disease. This suggests that the virus or host immune response may affect the protective function of endothelial barriers, ultimately being considered the most relevant event in severe and fatal dengue pathogenesis. The mechanisms that induce these alterations are diverse. It has been suggested that the high mobility group box 1 protein (HMGB1) may be involved in endothelial dysfunction. This non-histone nuclear protein has different immunomodulatory activities and belongs to the alarmin group. High concentrations of HMGB1 have been detected in patients with several infectious diseases, including dengue, and it could be considered as a biomarker for the early diagnosis of dengue and a predictor of complications of the disease. This review summarizes the main features of dengue infection and describes the known causes associated with endothelial dysfunction, highlighting the involvement and possible relationship between HMGB1 and DENV.

Acute-phase Serum Cytokine Levels and Correlation with Clinical Outcomes in Children and Adults with Primary and Secondary Dengue Virus Infection in Myanmar between 2017 and 2019

The dengue virus (DENV) has been endemic in Myanmar since 1970, causing outbreaks every 2–3 years. DENV infection symptoms range from mild fever to lethal hemorrhage. Clinical biomarkers must be identified to facilitate patient risk stratification in the early stages of infection. We analyzed 45 cytokines and other factors in serum samples from the acute phase of DENV infection (within 3–5 days of symptom onset) from 167 patients in Yangon, Myanmar, between 2017 and 2019. All of the patients tested positive for serum DENV nonstructural protein 1 antigen (NS1 Ag); 78.4% and 62.9% were positive for immunoglobulin M (IgM) and G (IgG), respectively; and 18.0%, 19.8%, and 11.9% tested positive for serotypes 1, 3, and 4, respectively. Although the DENV-4 viral load was significantly higher than those of DENV-1 or DENV-3, disease severity was not associated with viral load or serotype. Significant correlations were identified between disease severity and CCL5, SCF, PDGF-BB, IL-10, and TNF-α levels; between NS1 Ag and SCF, CCL5, IFN-α, IL-1α, and IL-22 levels; between thrombocytopenia and IL-2, TNF-α, VEGF-D, and IL-6 levels; and between primary or secondary infection and IL-2, IL-6, IL-31, IL-12p70, and MIP-1β levels. These circulating factors may represent leading signatures in acute DENV infections, reflecting the clinical outcomes in the dengue endemic region, Myanmar.

Negative Regulation of the IL-1 System by IL-1R2 and IL-1R8: Relevance in Pathophysiology and Disease

Interleukin-1 (IL-1) is a primary cytokine of innate immunity and inflammation. IL-1 belongs to a complex family including ligands with agonist activity, receptor antagonists, and an anti-inflammatory cytokine. The receptors for these ligands, the IL-1 Receptor (IL-1R) family, include signaling receptor complexes, decoy receptors, and negative regulators. Agonists and regulatory molecules co-evolved, suggesting the evolutionary relevance of a tight control of inflammatory responses, which ensures a balance between amplification of innate immunity and uncontrolled inflammation. IL-1 family members interact with innate immunity cells promoting innate immunity, as well as with innate and adaptive lymphoid cells, contributing to their differentiation and functional polarization and plasticity. Here we will review the properties of two key regulatory receptors of the IL-1 system, IL-1R2, the first decoy receptor identified, and IL-1R8, a pleiotropic regulator of different IL-1 family members and co-receptor for IL-37, the anti-inflammatory member of the IL-1 family. Their complex impact in pathology, ranging from infections and inflammatory responses, to cancer and neurologic disorders, as well as clinical implications and potential therapeutic exploitation will be presented.

Dengue Virus Infection and Risk of Parkinson's Disease: A Nationwide Longitudinal Study

Background: Increasing evidence suggests a potential relationship between viral infection and Parkinson’s disease (PD). Objective: Herein, we explore the association between infection by dengue virus and PD. Methods: Between 1997 and 2012, we recruited 1,422 patients with dengue fever and 14,220 matched controls (age, sex, time of enrollment, and medical and mental comorbidities) from the Taiwan National Health Insurance Research Database. We identified new onset of PD to the end of 2013. The Kaplan-Meier method was used to estimate the incidence rate of PD. Cox-regression analysis was applied to calculate the hazard ratios (HRs) with 95% confidence intervals (CIs) after adjustment for confounders. Results: During the follow up period, the dengue group had higher incidence of PD than the control group (1.2% vs. 0.4% , p = 0.001). Patients with dengue fever had a significantly higher risk of developing PD [HR, 2.59; 95% CI, 1.51–4.44] compared with the controls, after adjustments for demographic data, PD-related comorbidities, and all-cause clinical visits. The subgroup analysis, stratified by age and sex, found that higher risk for PD was statistically significant for male (HR, 3.51; 95% CI, 1.76–7.00) and patients aged >60 years (HR, 2.96; 95% CI, 1.62–5.41). Conclusion: The risk of PD was 2.59-fold higher in patients with dengue fever than in non-infected controls during the follow-up period. Clinicians need to monitor signs of PD during patient recovery from dengue fever. Additional studies are needed to confirm our results and investigate the mechanisms linking PD and dengue virus infection.

Mammalian animal models for dengue virus infection: a recent overview

Dengue, a rapidly spreading mosquito-borne human viral disease caused by dengue virus (DENV), is a public health concern in tropical and subtropical areas due to its expanding geographical range. DENV can cause a wide spectrum of illnesses in humans, ranging from asymptomatic infection or mild dengue fever (DF) to life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Dengue is caused by four DENV serotypes; however, dengue pathogenesis is complex and poorly understood. Establishing a useful animal model that can exhibit dengue-fever-like signs similar to those in humans is essential to improve our understanding of the host response and pathogenesis of DENV. Although several animal models, including mouse models, non-human primate models, and a recently reported tree shrew model, have been investigated for DENV infection, animal models with clinical signs that are similar to those of DF in humans have not yet been established. Although animal models are essential for understanding the pathogenesis of DENV infection and for drug and vaccine development, each animal model has its own strengths and limitations. Therefore, in this review, we provide a recent overview of animal models for DENV infection and pathogenesis, focusing on studies of the antibody-dependent enhancement (ADE) effect in animal models.

Different Profiles of Cytokines, Chemokines and Coagulation Mediators Associated with Severity in Brazilian Patients Infected with Dengue Virus

The incidence of dengue in Latin America has increased dramatically during the last decade. Understanding the pathogenic mechanisms in dengue is crucial for the identification of biomarkers for the triage of patients. We aimed to characterize the profile of cytokines (IFN-γ, TNF-α, IL-1β, IL-6, IL-18 and IL-10), chemokines (CXCL8/IL-8, CCL2/MCP-1 and CXCL10/IP-10) and coagulation mediators (Fibrinogen, D-dimer, Tissue factor-TF, Tissue factor pathway inhibitor-TFPI and Thrombomodulin) during the dengue-4 epidemic in Brazil. Laboratory-confirmed dengue cases had higher levels of TNF-α (p < 0.001), IL-6 (p = 0.005), IL-10 (p < 0.001), IL-18 (p = 0.001), CXCL8/IL-8 (p < 0.001), CCL2/MCP-1 (p < 0.001), CXCL10/IP-10 (p = 0.001), fibrinogen (p = 0.037), D-dimer (p = 0.01) and TFPI (p = 0.042) and lower levels of TF (p = 0.042) compared to healthy controls. A principal component analysis (PCA) distinguished between two profiles of mediators of inflammation and coagulation: protective (TNF-α, IL-1β and CXCL8/IL-8) and pathological (IL-6, TF and TFPI). Lastly, multivariate logistic regression analysis identified high aspartate aminotransferase-to-platelet ratio index (APRI) as independent risk factors associated with severity (adjusted OR: 1.33; 95% CI 1.03–1.71; p = 0.027), the area under the receiver operating characteristics curve (AUC) was 0.775 (95% CI 0.681–0.869) and an optimal cutoff value was 1.4 (sensitivity: 76%; specificity: 79%), so it could be a useful marker for the triage of patients attending primary care centers.