The chemokine landscape: one system multiple shades.

Leukocyte trafficking is mainly governed by chemokines, chemotactic cytokines, which can be concomitantly produced in tissues during homeostatic conditions or inflammation. After the discovery and characterization of the individual chemokines, we and others have shown that they present additional properties. The first discoveries demonstrated that some chemokines act as natural antagonists on chemokine receptors, and prevent infiltration of leukocyte subsets in tissues. Later on it was shown that they can exert a repulsive effect on selective cell types, or synergize with other chemokines and inflammatory mediators to enhance chemokine receptors activities. The relevance of the fine-tuning modulation has been demonstrated in vivo in a multitude of processes, spanning from chronic inflammation to tissue regeneration, while its role in the tumor microenvironment needs further investigation. Moreover, naturally occurring autoantibodies targeting chemokines were found in tumors and autoimmune diseases. More recently in SARS-CoV-2 infection, the presence of several autoantibodies neutralizing chemokine activities distinguished disease severity, and they were shown to be beneficial, protecting from long-term sequelae. Here, we review the additional properties of chemokines that influence cell recruitment and activities. We believe these features need to be taken into account when designing novel therapeutic strategies targeting immunological disorders.

Evaluation of the Genes and Molecular Pathways Involved in Skin Lesions in Patients with COVID-19: Systems Biology and Bioinformatics Analysis Approach

Background: Coronavirus disease 2019 (COVID-19) was first identified in 2019 in Wuhan, China. Initially, although the number of COVID-19-infected individuals was very low, the infected cases increased as the virus spread worldwide. Skin manifestation is one of the symptoms observed in COVID-19 patients. Objectives: This study investigated the critical genes and molecular pathways involved in skin manifestations in COVID-19 patients through a biological system approach. Methods: In this study, the microarray dataset was downloaded from the Gene Expression Omnibus (GEO) database and analyzed for identifying differentially expressed genes (DEGs). The enrichment analysis of DEGs was evaluated using the DAVID database. Afterward, protein-protein interaction (PPI) networks were constructed via the STRING database and visualized using Cytoscape software. The hub genes were recognized using the cytoHubba. The interaction of the microRNA (miRNA)-hub genes, transcription factor (TF)-hub genes, and drug-hub genes was also evaluated in this study. Results: After analysis, some genes with the highest degree of connectivity, which were involved in the pathogenesis of HELLP syndrome were identified, and they were known as hub genes. These genes are as follows: IFN-gamma CXCL1, CCL2, CCL3, TLR2, IL-1B, CXCL6, IL-6, CCL4, and CXCL2. has-mir-34a-5p, has-mir-20a-5p, and has-mir-27a-3p as miRNA, as well as RELA as TF had the most interaction with the hub genes. Conclusion: Finally, IL-6 and CXCL10 that were compared to the other hub genes had the highest interaction with other genes;therefore, their role in Shamgir's pathogenesis is significant. Targeting the cited genes would be a strategy to prevent symptom manifestation and better patient management.

Unbalanced networks and disturbed kinetics of serum soluble mediators associated with distinct disease outcomes in severe COVID-19 patients.

The present study applied distinct models of descriptive analysis to explore the integrative networks and the kinetic timeline of serum soluble mediators to select a set of systemic biomarkers applicable for the clinical management of COVID-19 patients. For this purpose, a total of 246 participants (82 COVID-19 and 164 healthy controls - HC) were enrolled in a prospective observational study. Serum soluble mediators were quantified by high-throughput microbeads array on hospital admission (D0) and at consecutive timepoints (D1-6 and D7-20). The results reinforce that the COVID-19 group exhibited a massive storm of serum soluble mediators. While increased levels of CCL3 and G-CSF were associated with the favorable prognosis of non-mechanical ventilation (nMV) or discharge, high levels of CXCL10 and IL-6 were observed in patients progressing to mechanical ventilation (MV) or death. At the time of admission, COVID-19 patients presented a complex and robust serum soluble mediator network, with a higher number of strong correlations involving IFN-γ, IL-1Ra and IL-9 observed in patients progressing to MV or death. Multivariate regression analysis demonstrates the ability of serum soluble mediators to cluster COVID-19 from HC. Ascendant fold change signatures and the kinetic timeline analysis further confirmed that the pairs "CCL3 and G-CSF" and "CXCL10 and IL-6" were associated with favorable or poor prognosis, respectively. A selected set of systemic mediators (IL-6, IFN-γ, IL-1Ra, IL-13, PDGF and IL-7) were identified as putative laboratory markers, applicable as complementary records for the clinical management of patients with severe COVID-19.

Does previous anti-thrombotic use affect the course of coronavirus disease-2019?

Introduction: Proinflammatory cytokines, produced as an immune response in severe acute respiratory syndrome-coronavirus 2 infection, activate the coagulation cascade as well. In this study, we investigated the difference in the clinical course of patients who had been already using anti-thrombotic therapy before coronavirus disease-2019 (COVID-19) for any reason compared to the group who had not. Methods: In this retrospective, multicenter study;patients who were hospitalized between March 11 and July 1, 2020 were divided into two main groups as who had been on anti-thrombotic therapy for any indication use previously at the time of admission or who had not been on anti-thrombotic therapy at the time of admission, and their selected clinical parameters were compared. Results: After analyzing the study population of 124 patients with a homogeneous distribution in terms of age and gender, the comparison of anti-thrombotic users and non-users showed no significant difference in hospitalization. There was a statistically significant decrease in mechanical ventilation apply rate, intensive care unit duration and mortality rate between the group using anti-thrombotic compared to the group not using it (p<0.05). Conclusion: It has already been shown that COVID-19 patients are more prone to thromboembolic events as it activates the coagulation cascade with the cytokine storm it creates and thus the mortality of COVID-19 infection increases significantly. Parallel to this fact the results of our study demonstrated that using anti-thrombotic therapy for any reason may affect the bad prognosis of the disease positively.

Anti-inflammatory actions of Pentosan polysulfate sodium in a mouse model of influenza virus A/PR8/34-induced pulmonary inflammation.

Introduction: There is an unmet medical need for effective anti-inflammatory agents for the treatment of acute and post-acute lung inflammation caused by respiratory viruses. The semi-synthetic polysaccharide, Pentosan polysulfate sodium (PPS), an inhibitor of NF-kB activation, was investigated for its systemic and local anti-inflammatory effects in a mouse model of influenza virus A/PR8/1934 (PR8 strain) mediated infection. Methods: Immunocompetent C57BL/6J mice were infected intranasally with a sublethal dose of PR8 and treated subcutaneously with 3 or 6 mg/kg PPS or vehicle. Disease was monitored and tissues were collected at the acute (8 days post-infection; dpi) or post-acute (21 dpi) phase of disease to assess the effect of PPS on PR8-induced pathology. Results: In the acute phase of PR8 infection, PPS treatment was associated with a reduction in weight loss and improvement in oxygen saturation when compared to vehicle-treated mice. Associated with these clinical improvements, PPS treatment showed a significant retention in the numbers of protective SiglecF+ resident alveolar macrophages, despite uneventful changes in pulmonary leukocyte infiltrates assessed by flow cytometry. PPS treatment in PR8- infected mice showed significant reductions systemically but not locally of the inflammatory molecules, IL-6, IFN-g, TNF-a, IL-12p70 and CCL2. In the post-acute phase of infection, PPS demonstrated a reduction in the pulmonary fibrotic biomarkers, sICAM-1 and complement factor C5b9. Discussion: The systemic and local anti-inflammatory actions of PPS may regulate acute and post-acute pulmonary inflammation and tissue remodeling mediated by PR8 infection, which warrants further investigation.

Anti-Inflammatory Therapy of Infections

Anti-inflammatory treatment of infections is challenging due to the heterogeneity of etiologic agents and complex immune interactions. Nevertheless, anti-inflammatory medications are commonly used in infections to reduce unpleasant symptoms and to modify host response. They may play a fundamental role in managing infection with over-inflammation by decreasing inflammatory organ damage, e.g., COVID-19. However, by its inherent inhibition of immune functions, they might also contribute to the development of serious bacterial infections. Moreover, reducing a patient's symptoms and signs may provide a false sense of security and delay diagnosing threatening infections. © 2022 Elsevier Inc. All rights reserved.

A systematic review and meta-analysis on blood levels of cytokines/chemokines in COVID-19 cases

We assessed the blood levels of the most important factors such as cytokines/chemokines in Coronavirus disease-2019 (COVID-19). PubMed/Medline and Scopus as two important databases were searched up to March 26, 2020. To analyze the data, we used Review Manager 5.3 software. Out of forty-two records retrieved from two databases, 10 studies were involved in the analysis. Thirty-three cytokines/chemokines were checked. The levels of 27 cytokines/ chemokines in COVID-19 patients were higher than the healthy controls, and among 20 cytokines/chemokines;the levels of 10 cytokines/chemokines in severe COVID-19 patients were higher than non-severe COVID-19 patients. Also, out of three cytokines, one had a higher level in the intensive care unit (ICU) patients compared to the non-ICU patients. The findings showed the cytokine storm syndrome in COVID-19 patients, especially in patients with severe disease.

Pathophysiology of SARS-CoV-2 Infection and COVID-19

A detailed understanding of the pathophysiologic mechanisms of severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) infection and Coronavirus disease 2019 (COVID-19) is vital for improving patient management - to facilitate prompt recognition of progression to severe disease and effective therapeutic strategies. This chapter summarizes the underlyingpathophysiology in the lungs and other organs of COVID- 19 patients. The roles of the cytokine storm culminating in exaggerated inflammatory responses and formation of neutrophil extracellular traps (NETs) are discussed. Pathological features of the various stages from the onset of COVID-19 are outlined - progressing from early mild infection to severe clinical illness to the critically ill phase. © 2023 by World Scientific Publishing Co. Pte. Ltd.

Matrix metalloproteinases in COVID-19: underlying significance

The role of matrix metalloproteinases (MMPs) in pathogenesis and severity of coronavirus disease 2019 (COVID-19) is under extensive exploration. MMPs are a family of extracellular proteases involved in a variety of physiological and pathological processes and conditions. The role of MMPs in COVID-19 stems from the pathogenesis resulting in the release of chemokines and pro-inflammatory markers which cause pulmonary oedema. In addition, the approaches to treatment of COVID-19 often are associated with some complications like acute lung injury due to extracellular matrix remodelling. In this respect, the aim of this review is to summarize, interpret and evaluate the significance of matrix metalloproteinases in SARS-CoV-2 infection in terms of the severity of the condition and delve into potential treatment from this perspective as well as highlighting the physiological and protective role of some MMPs. © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Evaluating functional roles of CXCL1:CXCL2 signaling in pre-clinical mouse models of neuroinflammation and disease

Intracranial infection with the JHM strain of the mouse hepatitis virus (JHMV), a member of the Betacoronavirus family, causes acute encephalomyelitis resulting in immune-mediated demyelination. JHMV infection is an excellent model to study both viral-induced neurologic disease and the immunologic mechanisms contributing to demyelination and is a well-accepted model for the human demyelinating disease multiple sclerosis (MS). Following JHVM infection of the CNS, the innate immune system is rabidly mobilized and secretion of the ELR+ family of chemokines, including CXCL1, which contribute to multiple cell processes including migration, differentiation, and maturation. Using a transgenic mouse in which the neutrophil chemoattractant CXCL1 can be induced to be overexpressed from astrocytes, we previously showed that sustained neutrophil infiltration exacerbates demyelination and clinical severity in the JHMV model. Subsequently, we wanted to replicate these findings in the prototypic experimental autoimmune encephalomyelitis (EAE) model and also to elucidate the mechanisms by which neutrophils are augmenting white matter damage in the JHMV mouse model of demyelination. In the EAE model we found that sustained infiltration of neutrophils into the CNS increased severity of demyelination and worsened clinical score without affecting the infiltration of other immune cell populations. Additionally, blocking neutrophil over accumulation with anti-CXCR2 antibody ameliorated these negative effects. We also found in the JHMV model that sustained neutrophil infiltration exacerbated demyelination through both direct and indirect effects. Neutrophils in the spinal cord were found to have a more mature phenotype associated with increased granularity and proinflammatory protein production and also polarized other infiltrating immune cells to a more inflammatory phenotype.The CXCR2/CXCL1 signaling pathway is also important for proper myelination of the CNS, specifically in the positional migration and proliferation of oligodendrocyte precursor cells (OPCs) in the developing mouse brain. In addition, CXCR2 signaling has been implicated in regulating remyelination in several pre-clinical models of demyelination. In order to determine the role of CXCR2 signaling on OPCs we developed a mouse model in which Cxcr2 was conditionally ablated following tamoxifen treatment in adult mice. We found using the JHMV model that Cxcr2 silencing on OPCs did not affect clinical disease, infiltrating immune cells, or demyelination. It also had no effect on the structural myelin composition of noninfected transgenic mice. However, we did find that Cxr2 ablation resulted in more mature oligodendroglia and more remyelination at later time points following JHMV infection. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

Chemokines and chemokine receptors during COVID-19 infection.

Chemokines are crucial inflammatory mediators needed during an immune response to clear pathogens. However, their excessive release is the main cause of hyperinflammation. In the recent COVID-19 outbreak, chemokines may be the direct cause of acute respiratory disease syndrome, a major complication leading to death in about 40% of severe cases. Several clinical investigations revealed that chemokines are directly involved in the different stages of SARS-CoV-2 infection. Here, we review the role of chemokines and their receptors in COVID-19 pathogenesis to better understand the disease immunopathology which may aid in developing possible therapeutic targets for the infection.

Pathogenesis of Anemia in Canine Babesiosis: Possible Contribution of Pro-Inflammatory Cytokines and Chemokines-A Review.

Canine babesiosis is a tick-borne protozoan disease caused by intraerythrocytic parasites of the genus Babesia. The infection may lead to anemia in infected dogs. However, anemia is not directly caused by the pathogen. The parasite's developmental stages only have a marginal role in contributing to a decreased red blood cell (RBC) count. The main cause of anemia in affected dogs is the immune response to the infection. This response includes antibody production, erythrophagocytosis, oxidative damage of RBCs, complement activation, and antibody-dependent cellular cytotoxicity. Moreover, both infected and uninfected erythrocytes are retained in the spleen and sequestered in micro-vessels. All these actions are driven by pro-inflammatory cytokines and chemokines, especially IFN-γ, TNF-α, IL-6, and IL-8. Additionally, imbalance between the actions of pro- and anti-inflammatory cytokines plays a role in patho-mechanisms leading to anemia in canine babesiosis. This article is a review of the studies on the pathogenesis of anemia in canine babesiosis and related diseases, such as bovine or murine babesiosis and human or murine malaria, and the role of pro-inflammatory cytokines and chemokines in the mechanisms leading to anemia in infected dogs.

Cellular and molecular features of COVID-19 associated ARDS: therapeutic relevance.

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection can be asymptomatic or cause a disease (COVID-19) characterized by different levels of severity. The main cause of severe COVID-19 and death is represented by acute (or acute on chronic) respiratory failure and acute respiratory distress syndrome (ARDS), often requiring hospital admission and ventilator support.The molecular pathogenesis of COVID-19-related ARDS (by now termed c-ARDS) is still poorly understood. In this review we will discuss the genetic susceptibility to COVID-19, the pathogenesis and the local and systemic biomarkers correlated with c-ARDS and the therapeutic options that target the cell signalling pathways of c-ARDS.

Effect of Chemokine Gene Variants on Covid-19 Disease Severity.

Patients immune phenotype/genotype data may be useful to understand the molecular mechanisms involved in SARS-CoV-2 infection and can contribute to the identify the different levels of disease severity. The roles of chemokines have been reported in the coronavirus-related diseases SARS and MERS and they may likewise play a critical role in the development of the symptoms of COVID-19 disease. We analyzed the association of the MCP-1-A2518 G, SDF-1-3'A, CCR5-delta32, CCR5-A55029 G, CXCR4-C138T and CCR2-V64I gene polymorphisms with COVID-19 severity to further unveil the immunological pathways leading to disease severity and death. Polymerase chain reaction(PCR)/Sanger sequencing analysis was performed for detection of the variations in 60 asymptomatic and 119 severe COVID-19 patients. In our study, we found that the frequencies of MCP-1 of GA genotype and G allele carriers were significantly higher in severe COVID-19 patients than the asymptomatic COVID-19 patients (p < .0001 and p: .005, respectively). However, no significant association was found for any of the other polymorphisms with the severity of COVID-19. Our findings suggest that there is a positive association between MCP-1-A2518 G gene variants with the severity of COVID-19. However, larger studies in different population which will focus on gene expression levels will help us to understand the capability of the mechanism role.

Association between the expression of toll-like receptors, cytokines, and homeostatic chemokines in SARS-CoV-2 infection and COVID-19 severity.

The recent identification of the involvement of the immune system response in the severity and mortality of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection highlights the importance of cytokines and chemokines as important factors in the clinical outcomes of COVID-19. However, the impact and roles of the BAFF/APRIL cytokine system, homeostatic chemokines (CXCL12, CXCL13, CCL19, and CCL21), as well as Toll-like receptor (TLR)-3/4 in COVID-19, have not been investigated. We sought to assess the expression levels and roles of TLR3/4, BAFF, APRIL, IFN-ß, homeostatic chemokines (CXCL12, CXCL13, CCL19, and CCL21), SARS-CoV-2 IgG and IgM antibodies in patients with critical (ICU) and non-ICU (mild) COVID-19 and their association with mortality and disease severity. Significant high levels of TLR-4 mRNA, IFN-ß, APRIL, CXCL13, and IgM and IgG antibodies were observed in ICU patients with severe COVID-19 compared to non-ICU COVID-19 patients and healthy controls. On the other hand, BAFF and CCL21 expression were significantly upregulated in non-ICU patients with COVID-19 compared with that in critical COVID-19 patients. The two groups did not differ in TLR-3, CXCL12, and CCL19 levels. Our findings show high expression levels of some inflammatory chemokines in ICU patients with COVID-19. These findings highlight the potential utility of chemokine antagonists as an immune-based treatment for the severe form of COVID-19. We also believe that selective targeting of TLR/spike protein interactions might lead to the development of a new COVID-19 therapy.

Innate and Adaptive Immunity during SARS-CoV-2 Infection: Biomolecular Cellular Markers and Mechanisms.

The coronavirus 2019 (COVID-19) pandemic was caused by a positive sense single-stranded RNA (ssRNA) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, other human coronaviruses (hCoVs) exist. Historical pandemics include smallpox and influenza, with efficacious therapeutics utilized to reduce overall disease burden through effectively targeting a competent host immune system response. The immune system is composed of primary/secondary lymphoid structures with initially eight types of immune cell types, and many other subtypes, traversing cell membranes utilizing cell signaling cascades that contribute towards clearance of pathogenic proteins. Other proteins discussed include cluster of differentiation (CD) markers, major histocompatibility complexes (MHC), pleiotropic interleukins (IL), and chemokines (CXC). The historical concepts of host immunity are the innate and adaptive immune systems. The adaptive immune system is represented by T cells, B cells, and antibodies. The innate immune system is represented by macrophages, neutrophils, dendritic cells, and the complement system. Other viruses can affect and regulate cell cycle progression for example, in cancers that include human papillomavirus (HPV: cervical carcinoma), Epstein-Barr virus (EBV: lymphoma), Hepatitis B and C (HB/HC: hepatocellular carcinoma) and human T cell Leukemia Virus-1 (T cell leukemia). Bacterial infections also increase the risk of developing cancer (e.g., Helicobacter pylori). Viral and bacterial factors can cause both morbidity and mortality alongside being transmitted within clinical and community settings through affecting a host immune response. Therefore, it is appropriate to contextualize advances in single cell sequencing in conjunction with other laboratory techniques allowing insights into immune cell characterization. These developments offer improved clarity and understanding that overlap with autoimmune conditions that could be affected by innate B cells (B1+ or marginal zone cells) or adaptive T cell responses to SARS-CoV-2 infection and other pathologies. Thus, this review starts with an introduction into host respiratory infection before examining invaluable cellular messenger proteins and then individual immune cell markers.

Spatial transcriptomic characterization of COVID-19 pneumonitis identifies immune circuits related to tissue injury.

Severe lung damage in COVID-19 involves complex interactions between diverse populations of immune and stromal cells. In this study, we used a spatial transcriptomics approach to delineate the cells, pathways and genes present across the spectrum of histopathological damage in COVID-19 lung tissue. We applied correlation network-based approaches to deconvolve gene expression data from 46 areas of interest covering >62,000 cells within well preserved lung samples from three patients. Despite substantial inter-patient heterogeneity, we discovered evidence for a common immune cell signaling circuit in areas of severe tissue that involves crosstalk between cytotoxic lymphocytes and pro-inflammatory macrophages. Expression of IFNG by cytotoxic lymphocytes was associated with induction of chemokines including CXCL9, CXCL10 and CXCL11 which are known to promote the recruitment of CXCR3+ immune cells. The tumour necrosis factor (TNF) superfamily members BAFF (TNFSF13B) and TRAIL (TNFSF10) were found to be consistently upregulated in the areas with severe tissue damage. We used published spatial and single cell SARS-CoV-2 datasets to confirm our findings in the lung tissue from additional cohorts of COVID-19 patients. The resulting model of severe COVID-19 immune-mediated tissue pathology may inform future therapeutic strategies.

The impact of supervised physical exercise on chemokines and cytokines in recovered COVID-19 patients.

COVID-19 is an infectious disease caused by the SARS-CoV-2 virus, which induces a high release of pro-inflammatory chemokines and cytokines, leading to severe systemic disorders. Further, evidence has shown that recovered COVID-19 patients still have some symptoms and disorders from COVID-19. Physical exercise can have many health benefits. It is known to be a potent regulator of the immune system, which includes frequency, intensity, duration, and supervised by a professional. Given the confinement and social isolation or hospitalization of COVID-19 patients, the population became sedentary or opted for physical exercise at home, assuming the guarantee of the beneficial effects of physical exercise and reducing exposure to SARS-CoV-2. This study aimed to investigate the effects of a supervised exercise protocol and a home-based unsupervised exercise protocol on chemokine and cytokine serum levels in recovered COVID-19 patients. This study was a prospective, parallel, two-arm clinical trial. Twenty-four patients who had moderate to severe COVID-19 concluded the intervention protocols of this study. Participants were submitted to either supervised exercise protocol at the Clinical Hospital of the Federal University of Pernambuco or home-based unsupervised exercise for 12 weeks. We analyzed serum levels of chemokines (CXCL8/IL-8, CCL5/RANTES, CXCL9/MIG, CCL2/MCP-1, and CXCL10/IP-10) and cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, TNF-α, and IFN-γ). Before the interventions, no significant differences were observed in the serum levels of chemokines and cytokines between the supervised and home-based unsupervised exercise groups. The CXCL8/IL-8 (p = 0.04), CCL2/MCP-1 (p = 0.03), and IFN-γ (p = 0.004) levels decreased after 12 weeks of supervised exercise. In parallel, an increase in IL-2 (p = 0.02), IL-6 (p = 0.03), IL-4 (p = 0.006), and IL-10 (p = 0.04) was observed after the supervised protocol compared to pre-intervention levels. No significant differences in all the chemokines and cytokines were found after 12 weeks of the home-based unsupervised exercise protocol. Given the results, the present study observed that supervised exercise was able to modulate the immune response in individuals with post-COVID-19, suggesting that supervised exercise can mitigate the inflammatory process associated with COVID-19 and its disorders. Clinical trial registration: https://ensaiosclinicos.gov.br/rg/RBR-7z3kxjk, identifier U1111-1272-4730.

Changing Disease Course of Crimean-Congo Hemorrhagic Fever in Children, Turkey.

Crimean-Congo hemorrhagic fever (CCHF), endemic in certain regions of the world, is listed as a priority disease with pandemic potential. Since CCHF was first identified in Turkey, children have been known to experience milder disease than adults. However, during the COVID-19 pandemic, we observed an unusually severe disease course, including hemophagocytic lymphohistiocytosis (HLH). We examined cytokine/chemokine profiles of 9/12 case-patients compared with healthy controls at 3 time intervals. Interferon pathway-related cytokines/chemokines, including interleukin (IL) 18, macrophage inflammatory protein 3α, and IL-33, were elevated, but tumor necrosis factor-α, IL-6, CXCL8 (formerly IL-8), and cytokines acting through C-C chemokine receptor 2 and CCR5 were lower among case-patients than controls. Interferon pathway activation and cytokines/chemokines acting through CCR2 and CCR5 improved health results among children with severe CCHF. Children can experience severe CCHF, including HLH, and HLH secondary to CCHF can be successfully treated with intravenous immunoglobulin and steroid therapy.

Zika and SARS-CoV-2: neuroinflammation and neurodegenerative outcomes

Through the emeigence of new viral infectious diseases, epidemics and pandemics have brought great impacts on public health in recent decades. In this review, we sought to understand the association between the neurological outcomes of two relevant infectious diseases, Zika and COVID-19. Zika can trigger neurological and ophthalmic damage in children born from infected mothers, as well as, Guillain-Barré syndrome, encephalitis, and myelitis in adults. On the other hand, the SARS-CoV-2 virus has great potential to trigger an inflammatory process in the optic nerve, with optic neuritis as the most reported pathology. Although Zika and SARS-CoV-2 infections are associated with different clinical manifestations, both may trigger similar pathogenic processes, through the induction of pro-inflammatory chemokines and cytokines release, triggering neurological and ophthalmological damage in infected patients. Elements in common have been found in both infections, such as antibodies against myelin oligodendrocyte glycoprotein, and the production of CXCL10, a chemokine responsible for the activation of several cellular types (T cells, eosinophils, monocytes and NK cells) in which are responsible to the induction of a cytokine cascade in the body. Based on these last findings, we suggest that both infections have similar activation characteristics as well as common pathogenic mechanisms associated with central nervous system involvement.