The study aimed to investigate the role of regulatory/pro-inflammatory mediators in the immunopathogenesis of Zika infection by analyzing mRNA expression kinetics in PMBC of ZIKV-infected patients. Blood samples were collected from patients at the “Pedro Kouri” Institute of Tropical Medicine between January and July 2017. RT-PCR was used to determine mRNA levels of immune mediators IL-10, IL-15, IL-17, TNF-α, MIP-1α, RANTES, FOXP3, IP-10, and TGF-β in PBMC. Results showed low levels of pro-inflammatory mediators and high levels of regulatory cytokines during acute and convalescent ZIKV phases, with a significant association between MIP-1α, IL-15, and IL-10 levels and joint pain. These findings suggest that regulatory cytokine mRNA levels may contribute to evading the antiviral immune response, shedding light on Zika's pathogenic mechanisms. The study also highlights the link between elevated IL-15 mRNA levels and joint pain.

Purpose:Oxysterol-binding protein-like 10 (OSBPL10) gene has been associated with reduced susceptibility to severe dengue in individuals of African descent. The aim of this study was to determine the possible effect of OSBPL10 on dengue virus (DENV) replication as well as the impact of African and European haplotypes of six OSBPL10 small nuclear polymorphisms (SNPs) on dengue multiplication and innate immune response. Methods:We conducted gene knockdown experiments targeting OSBPL10 in THP-1 and Huh-7D12 cell lines, followed by a DENV-2 replication assay. Extracellular viral load was determined using qRT-PCR. To investigate the impact of SNPs haplotypes on viral replication and gene expression we cultured peripheral blood mononuclear cells (PBMC) from individuals with homozygous African and European haplotypes of OSBPL10 with DENV-2. Individual genotyping was performed using High Resolution Melt (HRM) analysis. The level of viral replication was assessed through plaque assay, while RT-PCR was employed to determine the expression levels of RXR-α, IFN-γ, IL-10 and IL-8 genes. Results:In vitro OSBPL10 knockdown significantly reduced DENV-2 replication. Individuals carrying European haplotypes showed higher DENV titers along with elevated levels of RXR-α and IL-8 mRNA compared to those carrying African haplotypes, who exhibited lower viral loads alongside increased IFN-γ and IL-10 expression. Conclusions:Our findings further explore the role of OSBPL10 in DENV multiplication, immune response to infection. The European haplotypes of OSBPL10 appear to increase DENV replication and promote RXR-α and IL-8 mRNA expression which correlates with the suppressive effect of these mediators on type I IFN, promoting viral replication and a deficient antiviral response. In contrast, the African haplotype showed a reduction in DENV replication and enhanced IFN-γ and IL-10 mRNA expression, which could be related to the better management of dengue infection and the low frequency of severe disease in this ethnic groupe.

Transcriptomics, proteomics and pathogen-host interactomics data are being explored for the in silico–informed selection of drugs, prior to their functional evaluation. The effectiveness of this kind of strategy has been put to the test in the current COVID-19 pandemic, and it has been paying off, leading to a few drugs being rapidly repurposed as treatment against SARS-CoV-2 infection. Several neglected tropical diseases, for which treatment remains unavailable, would benefit from informed in silico investigations of drugs, as performed in this work for Dengue fever disease. We analyzed transcriptomic data in the key tissues of liver, spleen and blood profiles and verified that despite transcriptomic differences due to tissue specialization, the common mechanisms of action, “Adrenergic receptor antagonist”, “ATPase inhibitor”, “NF-kB pathway inhibitor” and “Serotonin receptor antagonist”, were identified as druggable (e.g., oxprenolol, digoxin, auranofin and palonosetron, respectively) to oppose the effects of severe Dengue infection in these tissues. These are good candidates for future functional evaluation and clinical trials.

Early recognition of severe forms of coronavirus disease 2019 (COVID-19) is essential for an opportune and effective intervention, reducing life-risking complications. An altered inflammatory immune response seems to be associated with COVID-19's pathogenesis and progression to severity. Here we demonstrate the utility of early nasopharyngeal swab samples for detection of the early expression of immune markers and the potential value of CCL2/MCP-1 in predicting disease outcome.

Population genetics theory predicted that rare frequent markers would be the main contributors for heritability of complex diseases, but meta-analyses of genome-wide association studies are revealing otherwise common markers, present in all population groups, as the identified candidate genes. In this work, we applied a population-genetics informed meta-analysis to 10 markers located in seven genes said to be associated with dengue fever disease. Seven markers (in PLCE1, CD32, CD209, OAS1 and OAS3 genes) have high-frequency and the other three (in MICB and TNFA genes) have intermediate frequency. Most of these markers have high discriminatory power between population groups, but their frequencies follow the rules of genetic drift, and seem to have not been under strong selective pressure. There was a good agreement in directional consistency across trans-ethnic association signals, in East Asian and Latin American cohorts, with heterogeneity generated by randomness between studies and especially by low sample sizes. This led to confirm the following significant associations: with DF, odds ratio of 0.67 for TNFA-rs1800629-A; with DHF, 0.82 for CD32-rs1801274-G; with DSS, 0.55 for OAS3-rs2285933-G, 0.80 for PLCE1-rs2274223-G and 1.32 for MICB-rs3132468-C. The overall genetic risks confirmed sub-Saharan African populations and descendants as the best protected against the severer forms of the disease, while Southeast and Northeast Asians are the least protected ones. European and close neighbours are the best protected against dengue fever, while, again, Southeast and Northeast Asians are the least protected ones. These risk scores provide important predictive information for the largely naïve European and North American regions, as well as for Africa where misdiagnosis with other hemorrhagic diseases is of concern.

Ethnic groups can display differential genetic susceptibility to infectious diseases. The arthropod-born viral dengue disease is one such disease, with empirical and limited genetic evidence showing that African ancestry may be protective against the haemorrhagic phenotype. Global ancestry analysis based on high-throughput genotyping in admixed populations can be used to test this hypothesis, while admixture mapping can map candidate protective genes. A Cuban dengue fever cohort was genotyped using a 2.5 million SNP chip. Global ancestry was ascertained through ADMIXTURE and used in a fine-matched corrected association study, while local ancestry was inferred by the RFMix algorithm. The expression of candidate genes was evaluated by RT-PCR in a Cuban dengue patient cohort and gene set enrichment analysis was performed in a Thai dengue transcriptome. OSBPL10 and RXRA candidate genes were identified, with most significant SNPs placed in inferred weak enhancers, promoters and lncRNAs. OSBPL10 had significantly lower expression in Africans than Europeans, while for RXRA several SNPs may differentially regulate its transcription between Africans and Europeans. Their expression was confirmed to change through dengue disease progression in Cuban patients and to vary with disease severity in a Thai transcriptome dataset. These genes interact in the LXR/RXR activation pathway that integrates lipid metabolism and immune functions, being a key player in dengue virus entrance into cells, its replication therein and in cytokine production. Knockdown of OSBPL10 expression in THP-1 cells by two shRNAs followed by DENV2 infection tests led to a significant reduction in DENV replication, being a direct functional proof that the lower OSBPL10 expression profile in Africans protects this ancestry against dengue disease.

Dengue is a tropical infectious disease caused by 1 of 4 dengue virus serotypes (DEN-1 to DEN-4). Immunity to a given dengue virus serotype provides protection against re infection with that same serotype (homotypic infection). However, subsequent infection with other serotype (heterotypic infection) markedly increases the risk for severe dengue disease, characterized by systemic plasma leakage that can cause hypovolemic shock, severe haemorrhagic manifestations or organs complications [1]. During the heterotypic secondary infection non neutralizing cross-reacting antibodies react with the virus and facilitate the viral entry to target cells via the Fcγ receptors, phenomenon known as antibody dependent enhancement (ADE) [2].

Introduccion: Se considera una prioridad para el diseno de una vacuna eficaz y segura contra el dengue, distinguir entre una respuesta inmune protectora y una patogenica frente a la infeccion natural. Las citoquinas se han asociado a la patogenesis del cuadro grave, sin embargo, muchos de los resultados de estudios realizados en diferentes partes del mundo son contradictorios o no reproducibles. El objetivo del presente trabajo es seleccionar los modelos mas utiles para el estudio de las citoquinas en la patogenesis del dengue. Material y metodos: Se determinaron los niveles de citoquinas proinflamatorias y antiinflamatorias en muestras de sueros de pacientes de dengue y se midio la expresion genica de esos mediadores en tejidos de fallecidos por dengue. Ademas se cuantifico el ARNm de las citoquinas en celulas sanguineas cultivadas in vitro con virus dengue y se evaluo la asociacion de variantes alelicas de los genes de las citoquinas estudiadas con las formas clinicas de la infeccion por dengue. Resultados: Los estudios in vivo sugirieron una aparente asociacion de las citoquinas antiinflamatorias con la gravedad del cuadro clinico, mientras los experimentos in vitro y el estudio del polimorfismo de genes evidenciaron el papel de los mediadores proinflamatorios en la patogenia del dengue grave y la infeccion secundaria heterotipica. Conclusiones: Son necesarios distintos modelos con enfoques complementarios para discernir el papel de los mediadores de respuesta inmune en la patogenesis de la enfermedad por dengue. Estudios con modelos unicos pueden llevar a conclusiones erradas.

Any of the four dengue serotypes can cause a severe disease, partly due to systemic inflammation orchestrated by mediators like cytokines and chemokines. We addressed the role of CCR1 and its ligands CCL3/MIP-1α and CCL5/RANTES in dengue infection using three different approaches: an ex vivo model exploring memory immune response in subjects with a well characterized dengue immune background, an in vivo study in patients with primary or secondary dengue infection, and an approach in fatal dengue. CCR1 and CCL3/MIP-1α gene expression showed differences after homotypic and heterotypic challenge according to dengue immune background of subjects, in correspondence with previous observations in Cuban dengue outbreaks. CCL5/RANTES gene expression was higher after homotypic challenge. CCR1 and CCL3/MIP-1α gene expression was higher in patients with secondary infection during critical days of the dengue disease, while the increase in RANTES expression started earlier than the observed for CCR1 and CCL3/MIP-1α. CCR1 and CCL3/MIP-1α gene expression was as high in brain as in spleen tissue from necropsy. Our results confirm the strong influence of previous immunity in subsequent dengue infections, and confer a possible pathogenic role to CCR1 and CCL3/MIP-1α in dengue disease and a possible protective role for CCL5/RANTES, probably through CCR5 interaction.

INTRODUCTION:The pathophysiological changes that determine the severity of dengue are still not well known, therefore it is important to study the probable relationship with the host genetic. METHODS:We analyzed the possible association between the FcγRIIa polymorphism and clinical signs in individuals who suffered dengue infection in 2006, using contingency tables. RESULTS:We found that bleeding was significantly associated to FcγRIIa H/H131 genotype (80%). CONCLUSION:Our results suggest that in clinical dengue infection the bleeding could be associated to FcγRIIa H/H131 genotype.

Dengue viruses (DV) are one of the most important arthropod-borne viral diseases in the developing world. DV can cause syndromes that are either self-limiting or severe. Allelic variants of human leukocyte antigen (HLA) genes have been demonstrated to be associated with disease susceptibility. Here we report the association of nonclassical HLA class I MICA–MICB genes with disease outcome during DV infection. A sequencing-based typing method and genotyping of MICA and MICB in a well-characterized group of Cuban individuals with dengue hemorrhagic fever (DHF), dengue fever (DF), or asymptomatic dengue infection (ADI) was performed. Statistical analysis revealed a tendency for MICA*008 and MICB*008 to associate with susceptibility to illness when symptomatic versus asymptomatic cases (odds ratio [OR] = 2.1, pv = 0.03, and OR = 10.4, p = 0.0096, respectively) were compared. Surprisingly, a stronger association of both allelic forms was observed for the DF patients compared with the ADI group (MICA*008, OR = 5.2, p = 0.0001; and MICB*008, OR = 13.2, p = 0.0025) rather than the severe cases. Major histocompatibility class I-related gene-related natural killer cells and/or γδ and αβ T-cell activation might regulate the development of symptomatic DF and DHF.

Increased serum levels of cytokines released by cells of the immune response have been detected in patients suffering from dengue disease. Likewise, secondary infections by a different dengue virus serotype result in a highest risk of development of the severe dengue disease. Both findings suggest that the memory immune response is one of the key players in the pathogenesis of this disease. Here we take advantage of the particular Cuban epidemiological situation in dengue to analyze a broad spectrum of cell-mediated immune response mediators at mRNA and protein level. Evidences for a regulatory immune pattern in homologous (TGF-beta, IL-10) vs. pro-inflammatory pattern (IFN-gamma, TNF-alpha) in heterologous dengue virus re-challenge were found, suggesting a possible association with the higher incidence of severe dengue cases in the latter case.

Dengue virus infection has emerged as one of the most important arthropod-borne viral diseases. Some dengue infected individuals develop the severe, life-threatening form of the disease, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). Host genetic factors may be relevant and may predispose some individuals to the severe illness. Human leukocyte antigen (HLA), FcγR, tumor necrosis factor (TNF)–α, and dendritic cell-specific intracellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), among others genes have been associated with the pathogenesis of dengue. Little is known, however, about the predictive value of cytokine genotypes for the clinical outcome of dengue infection. In this study, the TNF-α, interleukin (IL)–6, interferon (IFN)–γ, IL-10 and transforming growth factor (TGF)–β1 gene single nucleotide polymorphisms (SNP) were studied by polymerase chain reaction–sequence-specific primer in a group of individuals with the antecedent of DHF during a secondary infection in the sequence dengue 1/dengue 2. A control group was also included. TNF-α (−308) A allele and IL-10 (−1082/−819/−592) ACC/ATA haplotype were significantly associated with DHF. TNF-α (−308) GG and TGF-β1 (c25) GG genotypes were associated with protection. Our results suggest that genetic predisposition to a high TNF-α production and a low IL-10 production seems to increase the susceptibility to DHF during a secondary dengue 2 infection, whereas TGF-β1 high producers might be protected for developing DHF.

The pathogenesis of dengue infection is complicated and, despite intensive research, not well understood. Here, we review the burden of disease and the host (age, ethnicity, co-morbidities, immune and genetic factors) and viral (epidemiological and genetic factors) determinants for disease severity. This review is informed both by current knowledge of the topics and our specific experiences accumulated from Cuba and Vietnam.

Dengue virus has become endemic in most tropical urban areas throughout the world, and DHF has appeared concomitantly with this expansion. The intensity of dengue virus replication during the early stages of infection could determine clinical outcomes; therefore, it is important to understand the impact of dengue virus infection on the earliest immune defense against microbial infection, which also strongly regulates the adaptive immune responses. This study was aimed at evaluating the expression of the CC-chemokines MIP-1α/CCL3 and MCP-1/CCL2 in peripheral blood leukocytes using an ex vivo model resembling dengue infection in vivo, in subjects with a well characterized dengue immune background, due to the exceptional Cuban epidemiological situation in dengue. The expression of IFNγ, TNFα and IL10 was also evaluated, giving insight about the role of MCP-1 and MIP-1α in the interplay between innate and adaptive immunity. From individuals with different dengue immune background after dengue virus challenge, increased and different expression of the chemokines and cytokines studied was verified in peripheral blood mononuclear cells, thus demonstrating that the previous immunity to a dengue virus serotype has a strong influence on the early immune response after dengue re-infection.

OBJECTIVES:The acute manifestations of dengue are well known. The clinical symptoms that present during the convalescent phase of infection are less well characterized, but may be autoimmune-based. This study was undertaken to determine the prevalence of persistent clinical symptoms among individuals infected during the 2006 Cuban epidemic and to evaluate the immunological and genetic factors associated with their occurrence.METHODS:In 2008, clinical data and blood samples were collected from a random sample of adult individuals diagnosed during the 2006 epidemic with dengue fever (DF, n=68), dengue hemorrhagic fever (DHF, n=29), or an asymptomatic infection (AI, n=42). The presence of persistent symptoms was evaluated in all individuals and a psychological assessment was performed. IgG titers and the Fc receptor (FcR) were also evaluated. The following autoimmune markers were assessed in a subset (n=26) of symptomatic individuals: complement factors C3/C4, rheumatoid factor (RF), C-reactive protein (CRP), antinuclear antibodies (ANA), and immune complex (IC).RESULTS:Over half (55/97) the individuals with a prior of diagnosis of DF or DHF had persistent clinical symptoms in the 2 years following infection. The sequelae were unrelated to the initial diagnosis and were more common among women (44/55). No symptoms were reported in the AI group and all study participants had normal mental and cognitive function. Persistent clinical symptoms were associated with HH polymorphic variant (p=0.027) and high IgG titer (p=0.041). Autoimmune marker alterations were common (20/26) in the subset of symptomatic individuals evaluated.CONCLUSIONS:Clinical sequelae after recovery from an acute dengue virus infection are common in the 2 years following infection. The results obtained in this study suggest that persistent symptoms are associated with alterations in some immunological parameters and FcγRIIa gene polymorphism. This could suggest an autoimmune-based disturbance.