The current pandemic of coronavirus disease 19 (COVID-19) has affected millions of individuals and caused thousands of deaths worldwide. The pathophysiology of the disease is complex and mostly ...unknown. Therefore, identifying the molecular mechanisms that promote progression of the disease is critical to overcome this pandemic. To address such issues, recent studies have reported transcriptomic profiles of cells, tissues and fluids from COVID-19 patients that mainly demonstrated activation of humoral immunity, dysregulated type I and III interferon expression, intense innate immune responses and inflammatory signaling. Here, we provide novel perspectives on the pathophysiology of COVID-19 using robust functional approaches to analyze public transcriptome datasets. In addition, we compared the transcriptional signature of COVID-19 patients with individuals infected with SARS-CoV-1 and Influenza A (IAV) viruses. We identified a core transcriptional signature induced by the respiratory viruses in peripheral leukocytes, whereas the absence of significant type I interferon/antiviral responses characterized SARS-CoV-2 infection. We also identified the higher expression of genes involved in metabolic pathways including heme biosynthesis, oxidative phosphorylation and tryptophan metabolism. A BTM-driven meta-analysis of bronchoalveolar lavage fluid (BALF) from COVID-19 patients showed significant enrichment for neutrophils and chemokines, which were also significant in data from lung tissue of one deceased COVID-19 patient. Importantly, our results indicate higher expression of genes related to oxidative phosphorylation both in peripheral mononuclear leukocytes and BALF, suggesting a critical role for mitochondrial activity during SARS-CoV-2 infection. Collectively, these data point for immunopathological features and targets that can be therapeutically exploited to control COVID-19.
Transcriptomics has been used to evaluate immune responses during malaria in diverse cohorts worldwide. However, the high heterogeneity of cohorts and poor generalization of transcriptional ...signatures reported in each study limit their potential clinical applications.
We compiled 28 public datasets containing 1,556 whole blood or peripheral blood mononuclear cells (PBMC) transcriptome samples. We estimated effect sizes with Hedges´ g and DerSimonian-Laird random effects model for meta-analyses of uncomplicated malaria. Random forest models identified gene signatures that discriminate malaria from bacterial infections or malaria severity. Parasitological, hematological, immunological, and metabolomics data were used for validation.
We identified three gene signatures denominated the uncomplicated Malaria Meta-Signature (uMMS), which discriminates P. falciparum malaria from uninfected controls; the Malaria or Bacteria Signature (MoBS), that distinguishes malaria from sepsis and enteric fever; and the cerebral Malaria Meta-Signature (cMMS), which characterizes individuals with cerebral malaria. These signatures correlate with clinical hallmark features of malaria. Blood transcription modules (BTM) indicate immune regulation by glucocorticoids, whereas cell development and adhesion are associated with cerebral malaria.
Transcriptional meta-signatures reflecting immune cell responses provide potential biomarkers for translational innovation and suggest critical roles for metabolic regulators of inflammation during malaria.
This study investigated the peripheral frequency of monocytes, CD4 + T cell subsets and the systemic levels of cytokines in lean and obese men with different levels of cardiorespiratory fitness ...(CRF). Mononuclear cells were obtained from 45 lean and 45 obese men who were assigned into six groups according to their body mass index and CRF (low, moderate, or high VO2Peak) to analyze the frequency of monocyte subsets and subpopulations of CD4 + T cells (Treg cells, CD4 + CD25highCD127low; mTeff, CD4 + CD25‐CD39+; mTreg, CD4 + CD25+CD39+). The systemic levels of interleukin (IL)‐6, IL‐10, IL‐17a, IL‐33, leptin, and tumor necrosis factor‐alpha (TNF‐α) were also evaluated. Seven sedentary obese men performed one week of high‐intensity interval training (HIIT, 3 sessions/week), and blood samples were collected before and 24 hours after the last session for phenotypic analysis of T cells and monocytes. Obese individuals presented an inflammatory profile characterized by lower frequencies of Treg and mTreg cells and higher proportions of proinflammatory monocytes. However, higher CRF status increased the frequencies of Treg cells and mTreg cells and decreased the percentage of CD4 + mTeff cells and intermediate and non‐classical monocytes in the peripheral blood from lean and obese men. Systemic lower levels of proinflammatory (IL‐6 and TNF‐) cytokines and higher concentrations of IL‐10 and IL‐33 were observed in moderate and higher CRF in all subjects. HIIT increased the proportions of circulating mTreg and Treg cells in sedentary obese individuals. The immunoregulatory role of CRF contributes to the maintenance of low levels of inflammatory mediators.
Zika virus (ZIKV) is an arbovirus from the Flaviviridae family and Flavivirus genus. Neurological events have been associated with ZIKV-infected individuals, such as Guillain-Barré syndrome, an ...autoimmune acute neuropathy that causes nerve demyelination and can induce paralysis. With the increase of ZIKV infection incidence in 2015, malformation and microcephaly cases in newborns have grown considerably, which suggested congenital transmission. Therefore, the development of an effective vaccine against ZIKV became an urgent need. Live attenuated vaccines present some theoretical risks for administration in pregnant women. Thus, we developed an in silico multiepitope vaccine against ZIKV. All structural and non-structural proteins were investigated using immunoinformatics tools designed for the prediction of CD4 + and CD8 + T cell epitopes. We selected 13 CD8 + and 12 CD4 + T cell epitopes considering parameters such as binding affinity to HLA class I and II molecules, promiscuity based on the number of different HLA alleles that bind to the epitopes, and immunogenicity. ZIKV Envelope protein domain III (EDIII) was added to the vaccine construct, creating a hybrid protein domain-multiepitope vaccine. Three high scoring continuous and two discontinuous B cell epitopes were found in EDIII. Aiming to increase the candidate vaccine antigenicity even further, we tested secondary and tertiary structures and physicochemical parameters of the vaccine conjugated to four different protein adjuvants: flagellin, 50S ribosomal protein L7/L12, heparin-binding hemagglutinin, or RS09 synthetic peptide. The addition of the flagellin adjuvant increased the vaccine's predicted antigenicity. In silico predictions revealed that the protein is a probable antigen, non-allergenic and predicted to be stable. The vaccine's average population coverage is estimated to be 87.86%, which indicates it can be administered worldwide. Peripheral Blood Mononuclear Cells (PBMC) of individuals with previous ZIKV infection were tested for cytokine production in response to the pool of CD4 and CD8 ZIKV peptide selected. CD4 + and CD8 + T cells showed significant production of IFN-γ upon stimulation and IL-2 production was also detected by CD8 + T cells, which indicated the potential of our peptides to be recognized by specific T cells and induce immune response. In conclusion, we developed an in silico universal vaccine predicted to induce broad and high-coverage cellular and humoral immune responses against ZIKV, which can be a good candidate for posterior in vivo validation.
Viral replication and microbial translocation from the gut to the blood during HIV infection lead to hyperimmune activation, which contributes to the decline in CD4+ T cell numbers during HIV ...infection. Programmed death-1 (PD-1) and interleukin-10 (IL-10) are both upregulated during HIV infection. Blocking interactions between PD-1 and programmed death ligand-1 (PD-L1) and between IL-10 and IL-10 receptor (IL-10R) results in viral clearance and improves T cell function in animal models of chronic viral infections. Here we show that high amounts of microbial products and inflammatory cytokines in the plasma of HIV-infected subjects lead to upregulation of PD-1 expression on monocytes that correlates with high plasma concentrations of IL-10. Triggering of PD-1 expressed on monocytes by PD-L1 expressed on various cell types induced IL-10 production and led to reversible CD4+ T cell dysfunction. We describe a new function for PD-1 whereby microbial products inhibit T cell expansion and function by upregulating PD-1 levels and IL-10 production by monocytes after binding of PD-1 by PD-L1.
Background
Data on the prevalence of chronic pulmonary aspergillosis (CPA) in patients with active or cured tuberculosis (TB) are scarce, mainly due to diagnostic difficulties. The diagnosis of CPA ...is based on pulmonary symptoms and chest computed tomography (CT) scans and is considered confirmed when there is microbiological or serological evidence of Aspergillus spp. infection.
Objectives
To estimate the prevalence of CPA in patients treated or undergoing treatment for PTB, seen in two referral hospitals in Mato Grosso do Sul, Brazil.
Patients and Methods
A total of 193 consecutive patients who were treated or previously treated for pulmonary tuberculosis underwent prospective evaluation: (a) clinical evaluation; (b) chest CT scan; (c) sputum examination—culture for fungi and smears for direct mycology; (d) detection of anti‐Aspergillus fumigatus antibodies using an enzyme‐linked immunosorbent assay Platelia® test; and (e) anti‐Aspergillus spp. antibodies were assessed via a DID test.
Results
The global prevalence of CPA was 10.9% (95% confidence interval, 7.2%–16.1%), but it increased with the time of TB diagnosis. The variables independently associated with CPA were previous pulmonary tuberculosis over 4 years ago and haemoptysis. Cavities, pleural thickening and the presence of a fungal ball were the most frequent tomographic findings in patients with CPA.
Conclusions
The high prevalence observed and its increase over time suggest the need for continuous surveillance of CPA in patients with active or previous pulmonary tuberculosis and throughout life, with clinical, tomographic and serological evaluations (ELISA) for a timely diagnosis and a better prognosis.
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•Hospitalized COVID-19 patients had higher levels of LPS, sCD14 and cytokines.•LPS levels increases during disease progression in non-survivors patients (NSP).•IL-6, TNF-α, CCL2 and ...CCL5 increases during COVID-19 progression in NSP.•Plasma of NSP induces higher TLR4, CCR2, CCR5, CCR7, and CD69 expression in THP-1.•LPS coexisting with hyperinflammation may lead to worsening of COVID-19 outcomes.
Mucosal barrier alterations may play a role in the pathogenesis of several diseases, including COVID-19. In this study we evaluate the association between bacterial translocation markers and systemic inflammation at the earliest time-point after hospitalization and at the last 72 h of hospitalization in survivors and non-survivors COVID-19 patients. Sixty-six SARS-CoV-2 RT-PCR positive patients and nine non-COVID-19 pneumonia controls were admitted in this study. Blood samples were collected at hospital admission (T1) (Controls and COVID-19 patients) and 0–72 h before hospital discharge (T2, alive or dead) to analyze systemic cytokines and chemokines, lipopolysaccharide (LPS) concentrations and soluble CD14 (sCD14) levels. THP-1 human monocytic cell line was incubated with plasma from survivors and non-survivors COVID-19 patients and their phenotype, activation status, TLR4, and chemokine receptors were analyzed by flow cytometry. COVID-19 patients presented higher IL-6, IFN-γ, TNF-α, TGF-β1, CCL2/MCP-1, CCL4/MIP-1β, and CCL5/RANTES levels than controls. Moreover, LPS and sCD14 were higher at hospital admission in SARS-CoV-2-infected patients. Non-survivors COVID-19 patients had increased LPS levels concomitant with higher IL-6, TNF-α, CCL2/MCP-1, and CCL5/RANTES levels at T2. Increased expression of CD16 and CCR5 were identified in THP-1 cells incubated with the plasma of survivor patients obtained at T2. The incubation of THP-1 with T2 plasma of non-survivors COVID-19 leads to higher TLR4, CCR2, CCR5, CCR7, and CD69 expression. In conclusion, the coexistence of increased microbial translocation and hyperinflammation in patients with severe COVID-19 may lead to higher monocyte activation, which may be associated with worsening outcomes, such as death.
In this study, we evaluated the effects of autologous serum collected after two types of exercise on the in vitro inflammatory profile and T cell phenotype of resting peripheral blood mononuclear ...cells (PBMCs) in obese men. Serum samples and PBMCs were obtained from eight obese men who performed two exercise bouts-high intensity interval exercise (HIIE) and exhaustive exercise session to voluntary fatigue-in a randomized cross-over trial. Pre-exercise PBMCs were incubated with 50% autologous serum (collected before and after each exercise bout) for 4 h. In vitro experiments revealed that post-HIIE serum reduced the histone H4 acetylation status and NF-κB content of PBMCs and suppressed the production of both TNF-α and IL-6 by PBMCs, while increasing IL-10 production. Post-exhaustive exercise serum induced histone H4 hyperacetylation and mitochondrial depolarization in lymphocytes and increased TNF-α production. In vitro post-HIIE serum incubation resulted in an increase in the frequencies of CD4 + CTLA-4 + and CD4 + CD25+ T cells expressing CD39 and CD73. Post-exhaustive exercise serum decreased the frequency of CD4 + CD25 + CD73+ T cells but increased CD4 + CD25-CD39 + T cell frequency. Both post-exercise serums increased the proportions of CD4 + PD-1 + and CD8 + PD-1+ T cells. Blood serum factors released during exercise altered the immune response and T cell phenotype. The type of exercise impacted the immunomodulatory activity of the post-exercise serum on PBMCs.
Purinergic signaling modulates immune function and is involved in the immunopathogenesis of several viral infections. This study aimed to investigate alterations in purinergic pathways in coronavirus ...disease 2019 (COVID‐19) patients. Mild and severe COVID‐19 patients had lower extracellular adenosine triphosphate and adenosine levels, and higher cytokines than healthy controls. Mild COVID‐19 patients presented lower frequencies of CD4+CD25+CD39+ (activated/memory regulatory T cell mTreg) and increased frequencies of high‐differentiated (CD27−CD28−) CD8+ T cells compared with healthy controls. Severe COVID‐19 patients also showed higher frequencies of CD4+CD39+, CD4+CD25−CD39+ (memory T effector cell), and high‐differentiated CD8+ T cells (CD27−CD28−), and diminished frequencies of CD4+CD73+, CD4+CD25+CD39+ mTreg cell, CD8+CD73+, and low‐differentiated CD8+ T cells (CD27+CD28+) in the blood in relation to mild COVID‐19 patients and controls. Moreover, severe COVID‐19 patients presented higher expression of PD‐1 on low‐differentiated CD8+ T cells. Both severe and mild COVID‐19 patients presented higher frequencies of CD4+Annexin‐V+ and CD8+Annexin‐V+ T cells, indicating increased T‐cell apoptosis. Plasma samples collected from severe COVID‐19 patients were able to decrease the expression of CD73 on CD4+ and CD8+ T cells of a healthy donor. Interestingly, the in vitro incubation of peripheral blood mononuclear cell from severe COVID‐19 patients with adenosine reduced the nuclear factor‐κB activation in T cells and monocytes. Together, these data add new knowledge to the COVID‐19 immunopathology through purinergic regulation.
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