Association of IL1B -31C/T and IL1RA variable number of an 86-bp tandem repeat with dengue shock syndrome in Thailand

Dengue induces iNOS expression and nitric oxide synthesis in platelets through IL-1R

Introduction

Dengue is an arthropod-born disease caused by dengue virus (DENV), that may manifest as a mild illness or severe form, characterized by hemorrhagic fever and shock. Nitric oxide (NO) is a vasodilator signaling molecule and an inhibitor of platelet aggregation known to be increased in platelets from dengue patients. However, the mechanisms underlying NO synthesis by platelets during dengue are not yet elucidated. IL-1β is a pro-inflammatory cytokine able to induce iNOS expression in leukocytes and present in dengue patients at high levels. Nevertheless, the role of IL-1β in platelet activation, especially regarding iNOS expression, are not clear.

Methods

We prospectively followed a cohort of 28 dengue-infected patients to study NO synthesis in platelets and its relationship with disease outcomes. We used in vitro infection and stimulation models to gain insights on the mechanisms.

Results and Discussion

We confirmed that platelets from dengue patients express iNOS and produce higher levels of NO during the acute phase compared to healthy volunteers, returning to normal levels after recovery. Platelet NO production during acute dengue infection was associated with the presence of warning signs, hypoalbuminemia and hemorrhagic manifestations, suggesting a role in dengue pathophysiology. By investigating the mechanisms, we evidenced increased iNOS expression in platelets stimulated with dengue patients´ plasma, indicating induction by circulating inflammatory mediators. We then investigated possible factors able to induce platelet iNOS expression and observed higher levels of IL-1β in plasma from patients with dengue, which were correlated with NO production by platelets. Since platelets can synthesize and respond to IL-1β, we investigated whether IL-1β induces iNOS expression and NO synthesis in platelets. We observed that recombinant human IL-1β enhanced iNOS expression and dose-dependently increased NO synthesis by platelets. Finally, platelet infection with DENV in vitro induced iNOS expression and NO production, besides the secretion of both IL-1α and IL-1β. Importantly, treatment with IL-1 receptor antagonist or a combination of anti-IL-1α and anti-IL-1β antibodies prevented DENV-induced iNOS expression and NO synthesis. Our data show that DENV induces iNOS expression and NO production in platelets through mechanisms depending on IL-1 receptor signaling.

Identification of COVID-19 and Dengue Host Factor Interaction Networks Based on Integrative Bioinformatics Analyses

Background

The outbreak of Coronavirus disease 2019 (COVID-19) has become an international public health crisis, and the number of cases with dengue co-infection has raised concerns. Unfortunately, treatment options are currently limited or even unavailable. Thus, the aim of our study was to explore the underlying mechanisms and identify potential therapeutic targets for co-infection.

Methods

To further understand the mechanisms underlying co-infection, we used a series of bioinformatics analyses to build host factor interaction networks and elucidate biological process and molecular function categories, pathway activity, tissue-specific enrichment, and potential therapeutic agents.

Results

We explored the pathologic mechanisms of COVID-19 and dengue co-infection, including predisposing genes, significant pathways, biological functions, and possible drugs for intervention. In total, 460 shared host factors were collected; among them, CCL4 and AhR targets were important. To further analyze biological functions, we created a protein-protein interaction (PPI) network and performed Molecular Complex Detection (MCODE) analysis. In addition, common signaling pathways were acquired, and the toll-like receptor and NOD-like receptor signaling pathways exerted a significant effect on the interaction. Upregulated genes were identified based on the activity score of dysregulated genes, such as IL-1, Hippo, and TNF-α. We also conducted tissue-specific enrichment analysis and found ICAM-1 and CCL2 to be highly expressed in the lung. Finally, candidate drugs were screened, including resveratrol, genistein, and dexamethasone.

Conclusions

This study probes host factor interaction networks for COVID-19 and dengue and provides potential drugs for clinical practice. Although the findings need to be verified, they contribute to the treatment of co-infection and the management of respiratory disease.

Interferon lambda 1 is associated with dengue severity in Thailand

OBJECTIVES

Patients with dengue exhibit a range of symptoms from an acute febrile illness (dengue fever, DF), to dengue hemorrhagic fever (DHF), and to the most severe outcome, dengue shock syndrome (DSS). This study was performed to determine the host genetic factors responsible for dengue severity. Two single nucleotide polymorphisms (SNPs) of the interferon lambda 1 (IFNL1) gene (rs30461 and rs7247086) were analyzed for their association with dengue severity in a Thai population.

METHODS

This was a case-control association study involving 877 patients under the age of 15 years (DF, n = 386; DHF, n = 416; DSS, n = 75). Genotyping was performed by TaqMan real-time PCR assay.

RESULTS

It was found that the rs7247086 variant of IFNL1 was associated with DHF, but not DSS. Genotypes CT and TT and the T allele were protective against DHF (p = 0.03, odds ratio 0.62 for CT, odds ratio 0.13 for TT; and p = 0.01, odds ratio 0.54 for the T allele). The other SNP tested was not associated with DHF or DSS.

CONCLUSIONS

The rs7247086 variant of IFNL1 (the T allele) was found to be protective against DHF, suggesting that IFNL1 may play a role in the pathogenesis of DHF.

Platelet function in HIV plus dengue coinfection associates with reduced inflammation and milder dengue illness

HIV-infected subjects under virological control still exhibit a persistent proinflammatory state. Thus, chronic HIV infection changes the host homeostasis towards an adapted immune response that may affect the outcome of coinfections. However, little is known about the impact of HIV infection on inflammatory amplification and clinical presentation in dengue. Platelets have been shown to participate in immune response in dengue and HIV. We hypothesized that altered platelet responses in HIV-infected subjects may contribute to altered inflammatory milieu and disease progression in dengue. We prospectively followed a cohort of 84 DENV-infected patients of whom 29 were coinfected with HIV under virological control. We report that dengue and HIV coinfection progress with reduced inflammation and milder disease progression with lower risk of vascular instability. Even though the degree of thrombocytopenia and platelet activation were similar between dengue-infected and HIV plus dengue-coinfected patients, plasma levels of the platelet-derived chemokines RANTES/CCL5 and PF4/CXCL4 were lower in coinfection. Consistently, platelets from coinfected patients presented defective secretion of the stored-chemokines PF4 and RANTES, but not newly synthesized IL-1β, when cultured ex vivo. These data indicate that platelets from HIV-infected subjects release lower levels of chemokines during dengue illness, which may contribute to milder clinical presentation during coinfection.

Identification of genetic variants associated with dengue or West Nile virus disease: a systematic review and meta-analysis

BACKGROUND

Dengue and West Nile viruses are highly cross-reactive and have numerous parallels in geography, potential vector host (Aedes family of mosquitoes), and initial symptoms of infection. While the vast majority (> 80%) of both dengue and West Nile virus infections result in asymptomatic infections, a minority of individuals experience symptomatic infection and an even smaller proportion develop severe disease. The mechanisms by which these infections lead to severe disease in a subset of infected individuals is incompletely understood, but individual host differences including genetic factors and immune responses have been proposed. We sought to identify genetic risk factors that are associated with more severe disease outcomes for both viruses in order to shed light on possible shared mechanisms of resistance and potential therapeutic interventions.

METHODS

We applied a search strategy using four major databases (Medline, PubMed, Embase, and Global Health) to find all known genetic associations identified to date with dengue or West Nile virus disease. Here we present a review of our findings and a meta-analysis of genetic variants identified.

RESULTS

We found genetic variations that are significantly associated with infections of these viruses. In particular we found variation within the OAS1 (meta-OR = 0.83, 95% CI: 0.69-1.00) and CCR5 (meta-OR = 1.29, 95% CI: 1.08-1.53) genes is significantly associated with West Nile virus disease, while variation within MICB (meta-OR = 2.35, 95% CI: 1.68-3.29), PLCE1 (meta-OR = 0.55, 95% CI: 0.42-0.71), MBL2 (meta-OR = 1.54, 95% CI: 1.02-2.31), and IFN-γ (meta-OR = 2.48, 95% CI: 1.30-4.71), is associated with dengue disease.

CONCLUSIONS

Despite substantial heterogeneity in populations studied, genes examined, and methodology, significant associations with genetic variants were found across studies within both diseases. These gene associations suggest a key role for immune mechanisms in susceptibility to severe disease. Further research is needed to elucidate the role of these genes in disease pathogenesis and may reveal additional genetic factors associated with disease severity.

Platelets in Immune Response to Virus and Immunopathology of Viral Infections

Platelets are essential effector cells in hemostasis. Aside from their role in coagulation, platelets are now recognized as major inflammatory cells with key roles in the innate and adaptive arms of the immune system. Activated platelets have key thromboinflammatory functions linking coagulation to immune responses in various infections, including in response to virus. Recent studies have revealed that platelets exhibit several pattern recognition receptors (PRR) including those from the toll-like receptor, NOD-like receptor, and C-type lectin receptor family and are first-line sentinels in detecting and responding to pathogens in the vasculature. Here, we review the main mechanisms of platelets interaction with viruses, including their ability to sustain viral infection and replication, their expression of specialized PRR, and activation of thromboinflammatory responses against viruses. Finally, we discuss the role of platelet-derived mediators and platelet interaction with vascular and immune cells in protective and pathophysiologic responses to dengue, influenza, and human immunodeficiency virus 1 infections.

Host genetics and dengue fever

Dengue is a major worldwide problem in tropical and subtropical areas; it is caused by four different viral serotypes, and it can manifest as asymptomatic, mild, or severe. Many factors interact to determine the severity of the disease, including the genetic profile of the infected patient. However, the mechanisms that lead to severe disease and eventually death have not been determined, and a great challenge is the early identification of patients who are more likely to progress to a worse health condition. Studies performed in regions with cyclic outbreaks such as Cuba, Brazil, and Colombia have demonstrated that African ancestry confers protection against severe dengue. Highlighting the host genetics as an important factor in infectious diseases, a large number of association studies between genetic polymorphisms and dengue outcomes have been published in the last two decades. The most widely used approach involves case-control studies with candidate genes, such as the HLA locus and genes for receptors, cytokines, and other immune mediators. Additionally, a Genome-Wide Association Study (GWAS) identified SNPs associated with African ethnicity that had not previously been identified in case-control studies. Despite the increasing number of publications in America, Africa, and Asia, the results are quite controversial, and a meta-analysis is needed to assess the consensus among the studies. SNPs in the MICB, TNF, CD209, FcγRIIA, TPSAB1, CLEC5A, IL10 and PLCE1 genes are associated with the risk or protection of severe dengue, and the findings have been replicated in different populations. A thorough understanding of the viral, human genetic, and immunological mechanisms of dengue and how they interact is essential for effectively preventing dengue, but also managing and treating patients.

Association of genetic polymorphisms of IL1β -511 C>T, IL1RN VNTR 86 bp, IL6 -174 G>C, IL10 -819 C>T and TNFα -308 G>A, involved in symptomatic patients with dengue in Brazil

OBJECTIVE

In this study, single nucleotide polymorphisms (SNP) of interleukin (IL) 1β -511C>T, IL1RN VNTR 86 bp, IL6 -174G>C, IL10 -819C>T and TNFα -308G>A were analyzed by PCR-RFLP with symptoms of dengue with the clinical features.

SUBJECTS

196 individuals admitted to the São José Infectious Diseases Hospital with suspected dengue infection. Dengue was confirmed in 111 of the patients. The control group consisted of 85 other individuals confirmed without dengue.

RESULTS

It was demonstrated that the presence the T allele of IL1β (P < 0.05) was associated with susceptibility to developing the disease. Other results also suggested that the polymorphism in the combinations IL6 × IL1β (C and T alleles, respectively), IL1β (T allele) × IL1RN (*2/*2 genotype), IL6 (C allele) × TNFα (A allele), IL10 (C/T genotype) × TNFα (A/A genotype) (P < 0.01, P = 0.01, P < 0.05 and P = 0.03, respectively) were associated with predisposition to developing the disease and its symptoms.

CONCLUSIONS

In summary, the findings of this study in a Brazilian population point out the importance of studies of combinations of polymorphisms in the development of dengue, which can increase the risk of dengue infection and its severity.

Association of Polymorphisms in IL1β -511C>T, IL1RN 86 bp VNTR, and IL6 -174G>C Genes with Clinical Dengue Signs and Symptoms in Brazilian Dengue Patients

Dengue is an important infectious disease that has high morbidity and mortality rates in most tropical and subtropical areas of the world. The diversity of the clinical manifestations involved in the outcome of dengue virus infection is affected by the relationship between serotype/genotype of the virus, host immune status, host genetic background, and environmental factors. Polymorphisms in interleukin (IL) genes have been associated with risk of developing symptomatic dengue. This study aimed to determine the association of the single-nucleotide polymorphisms of IL1β -511C>T, IL1RN 86 bp VNTR, and IL6 -174G>C genes with the clinical features of 198 individuals admitted to the São José Infectious Diseases Hospital with suspected dengue infection. Dengue was confirmed in 118 of the patients. The control group consisted of 80 other individuals who had symptoms similar to dengue, but negative for that. A higher frequency of increased hematocrit (p = 0.009), leukopenia (p = 0.000007), neutropenia (p = 0.0004), lymphocytosis (p = 0.00001), monocytosis (p = 0.004), atypical lymphocytes (p = 0.03), and thrombocytopenia (p = 0.0000009) was observed in the dengue patients. Among the polymorphisms studied, only IL1β (-511C>T) was associated with dizziness, (p = 0.01), suggesting that IL1β may be related to hypotensive episodes and increased vascular permeability. These results pointed out the importance of the IL1β (-511C>T) polymorphism in the development of clinical symptoms of dengue symptomology.

Association of combinations of interleukin-10 and pro-inflammatory cytokine gene polymorphisms with dengue hemorrhagic fever

Pro-inflammatory and anti-inflammatory cytokines have been shown to play an important role in dengue disease pathogenesis. In the present study, to find out whether single nucleotide polymorphisms (SNPs) in the pro-inflammatory and anti-inflammatory cytokine genes are associated with dengue disease severity, SNPs in TNF, IFNG, IL1B, IL8, IL0, IL17A and IL17F genes were investigated using polymerase chain reaction based methods in 132 dengue (DEN) cases [87 dengue fever (DF), 45 dengue hemorrhagic fever (DHF) cases] and 108 apparently healthy controls (HC) from Pune, Maharashtra, western India. Under recessive genetic model (C/C vs. T/T+T/C), the TNF rs1799964 C/C genotype was significantly associated with DEN [P=0.014, OR with 95% CI 3.07 (1.18-7.98)]. Frequency of T/C genotype of IL17F rs763780 was significantly lower in DEN group as compared to HC [P=0.033, OR with 95% CI 0.43 (0.19-0.95)]. Under overdominant genetic model (A/T vs. A/A+T/T), IL8 rs4973 A/T genotype was negatively associated with DHF compared to HCs [p=0.029, OR with 95% CI 0.43 (0.20-0.93)]. Under overdominant genetic model, A/G genotype of IL10 rs1800871 was significantly negatively associated with DHF compared to DF cases [p=0.014, OR with 95% CI 0.35 (0.15-0.84)]. Significantly higher frequency of the combined genotype IL10 A/A-IFNG A/T and lower frequency of the combined genotypes IL10 A/G-IL1B A/A, IL10 A/G-IL8 A/T and IL10 A/G-IL17F T/T were observed in DHF cases compared to DF. The results suggest that heterozygous genotypes of IL8 rs4973 and IL10 rs1800871 are associated with reduced risk of DHF. Combinations of IL10 rs1800871 and pro-inflammatory cytokine genotypes influence the risk of DHF.