Altered cytokine levels and immune responses in patients with SARS-CoV-2 infection and related conditions

Kinome and phosphoproteome reprogramming underlies the aberrant immune responses in critically ill COVID-19 patients

SARS-CoV-2 infection triggers extensive host immune reactions, leading to severe diseases in certain individuals. However, the molecular basis underlying the excessive yet non-productive immune responses in severe COVID-19 remains incompletely understood. In this study, we conducted a comprehensive analysis of the peripheral blood mononuclear cell (PBMC) proteome and phosphoproteome in sepsis patients positive or negative for SARS-CoV-2 infection, as well as healthy subjects, using quantitative mass spectrometry. Our findings demonstrate dynamic changes in the COVID-19 PBMC proteome and phosphoproteome during disease progression, with distinctive protein or phosphoprotein signatures capable of distinguishing longitudinal disease states. Furthermore, SARS-CoV-2 infection induces a global reprogramming of the kinome and phosphoproteome, resulting in defective adaptive immune response mediated by the B and T lymphocytes, compromised innate immune responses involving the SIGLEC and SLAM family of immunoreceptors, and excessive cytokine-JAK-STAT signaling. In addition to uncovering host proteome and phosphoproteome aberrations caused by SARS-CoV-2, our work recapitulates several reported therapeutic targets for COVID-19 and identified numerous new candidates, including the kinases PKG1, CK2, ROCK1/2, GRK2, SYK, JAK2/3, TYK2, DNA-PK, PKCδ, and the cytokine IL-12.

COVID-19 convalescent plasma therapy decreases inflammatory cytokines: a randomized controlled trial

IMPORTANCE

This study examined the role that cytokines may have played in the beneficial outcomes found when outpatient individuals infected with SARS-CoV-2 were transfused with COVID-19 convalescent plasma (CCP) early in their infection. We found that the pro-inflammatory cytokine IL-6 decreased significantly faster in patients treated early with CCP. Participants with COVID-19 treated with CCP later in the infection did not have the same effect. This decrease in IL-6 levels after early CCP treatment suggests a possible role of inflammation in COVID-19 progression. The evidence of IL-6 involvement brings insight into the possible mechanisms involved in CCP treatment mitigating SARS-CoV-2 severity.

Amino acid catabolite markers for early prognostication of pneumonia in patients with COVID-19

Effective early-stage markers for predicting which patients are at risk of developing SARS-CoV-2 infection have not been fully investigated. Here, we performed comprehensive serum metabolome analysis of a total of 83 patients from two cohorts to determine that the acceleration of amino acid catabolism within 5 days from disease onset correlated with future disease severity. Increased levels of de-aminated amino acid catabolites involved in the de novo nucleotide synthesis pathway were identified as early prognostic markers that correlated with the initial viral load. We further employed mice models of SARS-CoV2-MA10 and influenza infection to demonstrate that such de-amination of amino acids and de novo synthesis of nucleotides were associated with the abnormal proliferation of airway and vascular tissue cells in the lungs during the early stages of infection. Consequently, it can be concluded that lung parenchymal tissue remodeling in the early stages of respiratory viral infections induces systemic metabolic remodeling and that the associated key amino acid catabolites are valid predictors for excessive inflammatory response in later disease stages.

Dynamics of inflammatory responses after SARS-CoV-2 infection by vaccination status in the USA: a prospective cohort study

BACKGROUND

Cytokines and chemokines play a critical role in the response to infection and vaccination. We aimed to assess the longitudinal association of COVID-19 vaccination with cytokine and chemokine concentrations and trajectories among people with SARS-CoV-2 infection.

METHODS

In this longitudinal, prospective cohort study, blood samples were used from participants enrolled in a multi-centre randomised trial assessing the efficacy of convalescent plasma therapy for ambulatory COVID-19. The trial was conducted in 23 outpatient sites in the USA. In this study, participants (aged ≥18 years) were restricted to those with COVID-19 before vaccination or with breakthrough infections who had blood samples and symptom data collected at screening (pre-transfusion), day 14, and day 90 visits. Associations between COVID-19 vaccination status and concentrations of 21 cytokines and chemokines (measured using multiplexed sandwich immunoassays) were examined using multivariate linear mixed-effects regression models, adjusted for age, sex, BMI, hypertension, diabetes, trial group, and COVID-19 waves (pre-alpha or alpha and delta).

FINDINGS

Between June 29, 2020, and Sept 30, 2021, 882 participants recently infected with SARS-CoV-2 were enrolled, of whom 506 (57%) were female and 376 (43%) were male. 688 (78%) of 882 participants were unvaccinated, 55 (6%) were partly vaccinated, and 139 (16%) were fully vaccinated at baseline. After adjusting for confounders, geometric mean concentrations of interleukin (IL)-2RA, IL-7, IL-8, IL-15, IL-29 (interferon-λ), inducible protein-10, monocyte chemoattractant protein-1, and tumour necrosis factor-α were significantly lower among the fully vaccinated group than in the unvaccinated group at screening. On day 90, fully vaccinated participants had approximately 20% lower geometric mean concentrations of IL-7, IL-8, and vascular endothelial growth factor-A than unvaccinated participants. Cytokine and chemokine concentrations decreased over time in the fully and partly vaccinated groups and unvaccinated group. Log10 cytokine and chemokine concentrations decreased faster among participants in the unvaccinated group than in other groups, but their geometric mean concentrations were generally higher than fully vaccinated participants at 90 days. Days since full vaccination and type of vaccine received were not correlated with cytokine and chemokine concentrations.

INTERPRETATION

Initially and during recovery from symptomatic COVID-19, fully vaccinated participants had lower concentrations of inflammatory markers than unvaccinated participants suggesting vaccination is associated with short-term and long-term reduction in inflammation, which could in part explain the reduced disease severity and mortality in vaccinated individuals.

FUNDING

US Department of Defense, National Institutes of Health, Bloomberg Philanthropies, State of Maryland, Mental Wellness Foundation, Moriah Fund, Octapharma, HealthNetwork Foundation, and the Shear Family Foundation.

MR-proADM as Prognostic Factor of Outcome in COVID-19 Patients

BACKGROUND

Serum mid-regional proadrenomedullin (MR-proADM) has emerged as a marker of organ failure (mainly lungs and kidneys) and poor prognosis in patients admitted to intensive care (IC); some reports also suggest it and other markers, such as Krebs von den Lungen-6 (KL-6) and interleukin-6 (IL-6), as a prognostic biomarker of COVID-19. The aim of the study was to evaluate the performance MR-proADM in hospitalized COVID-19 patients for predicting in-hospital mortality and need for non-invasive or invasive respiratory support.

METHODS

We enrolled 74 patients hospitalized in the COVID Unit of Siena Hospital from March to May 2020, for whom serum samples were available on admission for assay of MR-proADM, KL-6 and IL-6. Demographic data, comorbidities, medical history and clinical laboratory data on days 1-3 of admission and Simplified Acute Physiology Score and Simplified Organ Failure Assessment scores calculated at day 1 were collected retrospectively, as well as mortality and IC admission data.

RESULTS

12 patients died in hospital (16%) and 14 patients were admitted to IC (19%). Serum concentrations of MR-proADM on admission and on day 1 were higher among non-survivors than among survivors (p = 0.015 and p = 0.045, respectively), while those on day 3 were not significantly different. Patients needing respiratory support had higher MR-proADM concentrations on admission than the others (p = 0.046), and those requiring invasive mechanical ventilation had higher MR-proADM on day 1 (p = 0.017). Serum concentrations of KL-6 and IL-6 were significantly higher in non-survivors (p = 0.03 and p = 0.004, respectively). ROC curve analysis showed that serum MR-proADM on day 1 had the best accuracy in predicting death and/or IC admission (AUC = 0.9583, p = 0.0006); the combination of all three biomarkers further improved the accuracy of prediction of death or IC admission (AUC = 0.9793; p = 0.00004).

CONCLUSIONS

Our data sustain the potential of serum MR-proADM as a reliable prognostic biomarker of hospitalized COVID-19 patients and confirms the utility of the three markers in the management and risk stratification of hospitalized patients. The markers are collected mini-invasively and are quick to analyze and cost-effective.

Investigation of the potential of leukoreduction filters in the creation of anti-inflammatory compound

BACKGROUND

Some viruses such as SARS, SARS-CoV-2, and MERS cause an imbalance in immune responses and leads to an acute inflammatory reaction named cytokine storm. In this situation, an anti-inflammatory component can modulate the immune system and decrease mortality. The aim of this study was investigate the potential of leukoreduction filters (LRFs) in creating an anti-inflammatory compound.

MATERIALS AND METHODS

In this experimental study, firstly optimal dose of the anti-inflammatory drug was obtained through LRFs treatment with 0.1 mg, 0.4 mg, 0.6 mg of Betamethasone. Then inflammatory and anti-inflammatory cytokine in gene and protein level was evaluated. In the next step, LRFs were categorized into treatment 1, treatment 2, control assay, and control groups and treated with the optimal dose of the drug. Finally, the obtained compound was investigated for the concentration of IL1, IL6, and TNF-α as inflammatory and IL4, IL1Ra, and IL10 as anti-inflammatory cytokines.

RESULTS

The results of the current study showed that the concentration of 0.4 mg of Betamethasone lead to a significant increase of anti-inflammatory cytokine in gene and protein levels. The results also showed that the Betamethasone treated groups (treatment1) causes a significant increase in the secretion of anti-inflammatory cytokine compares to the control while inflammatory cytokine remained at the control level.

CONCLUSION

The results showed that under influence of anti-inflammatory drug treatments the production and secretion of anti-inflammatory cytokines can be induced in LRFs.

COVID-19: A state of art on immunological responses, mutations, and treatment modalities in riposte

Over the last few years, the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) unleashed a global public health catastrophe that had a substantial influence on human physical and mental health, the global economy, and socio-political dynamics. SARS-CoV-2 is a respiratory pathogen and the cause of ongoing COVID-19 pandemic, which testified how unprepared humans are for pandemics. Scientists and policymakers continue to face challenges in developing ideal therapeutic agents and vaccines, while at the same time deciphering the pathology and immunology of SARS-CoV-2. Challenges in the early part of the pandemic included the rapid development of diagnostic assays, vaccines, and therapeutic agents. The ongoing transmission of COVID-19 is coupled with the emergence of viral variants that differ in their transmission efficiency, virulence, and vaccine susceptibility, thus complicating the spread of the pandemic. Our understanding of how the human immune system responds to these viruses as well as the patient groups (such as the elderly and immunocompromised individuals) who are often more susceptible to serious illness have both been aided by this epidemic. COVID-19 causes different symptoms to occur at different stages of infection, making it difficult to determine distinct treatment regimens employed for the various clinical phases of the disease. Unsurprisingly, determining the efficacy of currently available medications and developing novel therapeutic strategies have been a process of trial and error. The global scientific community collaborated to research and develop vaccines at a neck-breaking speed. This review summarises the overall picture of the COVID-19 pandemic, different mutations in SARS-CoV-2, immune response, and the treatment modalities against SARS-CoV-2.

Divergent Cytokine and Chemokine Responses at Early Acute Simian Immunodeficiency Virus Infection Correlated with Virus Replication and CD4 T Cell Loss in a Rhesus Macaque Model

Cytokine and chemokine levels remain one of the significant predictive factors of HIV pathogenesis and disease outcome. Understanding the impact of cytokines and chemokines during early acute infection will help to recognize critical changes during HIV pathogenesis and might assist in establishing improved HIV treatment and prevention methods. Sixty-one cytokines and chemokines were evaluated in the plasma of an SIV-infected rhesus macaque model. A substantial change in 11 cytokines/growth factors and 9 chemokines were observed during acute infection. Almost all the cytokines/chemokines were below the baseline values for an initial couple of days of infection. We detected six important cytokines/chemokines, such as IL-18, IP-10, FLT3L, MCP-1, MCP-2, and MIP-3β, that can be used as biomarkers to predict the peripheral CD4+ T cell loss and increased viral replication during the acute SIV/HIV infection. Hence, regulating IL-18, IP-10, FLT3L, MCP-1, MCP-2, and MIP-3β expression might provide an antiviral response to combat acute SIV/HIV infection.

Multiplex Immunoassay Approaches Using Luminex® xMAP® Technology for the Study of COVID-19 Disease

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has been one of the most severe outbreaks of respiratory illness in history. The clinical symptoms of COVID-19 may be similar to flu, although they can be life-threatening, particularly in the elderly and immunocompromised population. Together with nucleic acid detection, serological testing has been essential for the diagnosis of SARS-CoV-2 infection but has been critically important for studying the epidemiology, serosurveillance, and for vaccine research and development. Multiplexed immunoassay technologies have a particular advantage as they can simultaneously measure multiple analytes from a single sample. xMAP technology is a multiplex analysis platform that can measure up to 500 analytes at the same time from the same sample. It has been shown to be an important tool for studying immune response to the various SARS-CoV-2 antigens, as well as for measuring host protein biomarker levels as prognostic indicators of COVID-19. In this chapter, we describe several key studies where xMAP technology was used for multiplexed analysis of SARS-COV-2 antibody responses and host protein expression in COVID-19 patients.

CD4+ T Cell Regulatory Network Underlies the Decrease in Th1 and the Increase in Anergic and Th17 Subsets in Severe COVID-19

In this model we use a dynamic and multistable Boolean regulatory network to provide a mechanistic explanation of the lymphopenia and dysregulation of CD4+ T cell subsets in COVID-19 and provide therapeutic targets. Using a previous model, the cytokine micro-environments found in mild, moderate, and severe COVID-19 with and without TGF-β and IL-10 was we simulated. It shows that as the severity of the disease increases, the number of antiviral Th1 cells decreases, while the the number of Th1-like regulatory and exhausted cells and the proportion between Th1 and Th1R cells increases. The addition of the regulatory cytokines TFG-β and IL-10 makes the Th1 attractor unstable and favors the Th17 and regulatory subsets. This is associated with the contradictory signals in the micro-environment that activate SOCS proteins that block the signaling pathways. Furthermore, it determined four possible therapeutic targets that increase the Th1 compartment in severe COVID-19: the activation of the IFN-γ pathway, or the inhibition of TGF-β or IL-10 pathways or SOCS1 protein; from these, inhibiting SOCS1 has the lowest number of predicted collateral effects. Finally, a tool is provided that allows simulations of specific cytokine environments and predictions of CD4 T cell subsets and possible interventions, as well as associated secondary effects.

Bioinformatics and systems biology approaches to identify molecular targeting mechanism influenced by COVID-19 on heart failure

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as a contemporary hazard to people. It has been known that COVID-19 can both induce heart failure (HF) and raise the risk of patient mortality. However, the mechanism underlying the association between COVID-19 and HF remains unclear. The common molecular pathways between COVID-19 and HF were identified using bioinformatic and systems biology techniques. Transcriptome analysis was performed to identify differentially expressed genes (DEGs). To identify gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways, common DEGs were used for enrichment analysis. The results showed that COVID-19 and HF have several common immune mechanisms, including differentiation of T helper (Th) 1, Th 2, Th 17 cells; activation of lymphocytes; and binding of major histocompatibility complex class I and II protein complexes. Furthermore, a protein-protein interaction network was constructed to identify hub genes, and immune cell infiltration analysis was performed. Six hub genes (FCGR3A, CD69, IFNG, CCR7, CCL5, and CCL4) were closely associated with COVID-19 and HF. These targets were associated with immune cells (central memory CD8 T cells, T follicular helper cells, regulatory T cells, myeloid-derived suppressor cells, plasmacytoid dendritic cells, macrophages, eosinophils, and neutrophils). Additionally, transcription factors, microRNAs, drugs, and chemicals that are closely associated with COVID-19 and HF were identified through the interaction network.

miRNA expression in COVID-19

Coronavirus disease 2019 (COVID-19) is regarded as a challenge in health system. Several studies have assessed the immune-related aspect of this disorder to identify the host-related factors that affect the course of COVID-19. microRNAs (miRNAs) as potent regulators of immune responses have gained much attention in this regard. Recent studies have shown aberrant expression of miRNAs in COVID-19 in association with disease course. Differentially expressed miRNAs have been enriched in pathways related with inflammation and antiviral immune response. miRNAs have also been regarded as potential therapeutic targets in COVID-19, particularly for management of pathological consequences of COVID-19. In the current review, we summarize the data about dysregulation of miRNAs in COVID-19.

Inflammatory mediators profile in patients hospitalized with COVID-19: A comparative study

Abnormal inflammatory mediator concentrations during SARS-CoV-2 infection may represent disease severity. We aimed to assess plasma inflammatory mediator concentrations in patients with SARS-CoV-2 in Addis Ababa, Ethiopia. In this study, 260 adults: 126 hospitalized patients with confirmed COVID-19 sorted into severity groups: severe (n=68) and mild or moderate (n=58), and 134 healthy controls were enrolled. We quantified 39 plasma inflammatory mediators using multiplex ELISA. Spearman rank correlation and Mann-Whitney U test were used to identify mechanistically coupled inflammatory mediators and compare disease severity. Compared to healthy controls, patients with COVID-19 had significantly higher levels of interleukins 1α, 2, 6, 7, 8, 10 and 15, C-reactive protein (CRP), serum amyloid A (SAA), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion protein 1 (VCAM-1), IFN-γ-inducible protein-10 (IP-10, CXCL10), macrophage inflammatory protein-1 alpha (MIP-1α, CCL3), eotaxin-3 (CCL26), interferon-gamma (IFN-γ), tumor necrosis factor-α (TNF-α), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and fms-like tyrosine kinase 1 (Flt-1). Patients with severe COVID-19 had higher IL-10 and lower macrophage-derived chemokine (MDC, CCL22) compared to the mild or moderate group (P<0.05). In the receiver operating characteristic curve, SAA, IL-6 and CRP showed strong sensitivity and specificity in predicting the severity and prognosis of COVID-19. Greater age and higher CRP had a significant association with disease severity (P<0.05). Our findings reveal that CRP, SAA, VCAM-1, CXCL10, CCL22 and IL-10 levels are promising biomarkers for COVID-19 disease severity, suggesting that plasma inflammatory mediators could be used as warning indicators of COVID-19 severity, aid in COVID-19 prognosis and treatment.

Neuropathological Aspects of SARS-CoV-2 Infection: Significance for Both Alzheimer's and Parkinson's Disease

Evidence suggests that SARS-CoV-2 entry into the central nervous system can result in neurological and/or neurodegenerative diseases. In this review, routes of SARS-Cov-2 entry into the brain via neuroinvasive pathways such as transcribrial, ocular surface or hematogenous system are discussed. It is argued that SARS-Cov-2-induced cytokine storm, neuroinflammation and oxidative stress increase the risk of developing neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Further studies on the effects of SARS-CoV-2 and its variants on protein aggregation, glia or microglia activation, and blood-brain barrier are warranted.

Toxicological impact of SARS-CoV-2 on the health of the neotropical fish, Poecilia reticulata

There have been significant impacts of the current COVID-19 pandemic on society including high health and economic costs. However, little is known about the potential ecological risks of this virus despite its presence in freshwater systems. In this study, we aimed to evaluate the exposure of Poecilia reticulata juveniles to two peptides derived from Spike protein of SARS-CoV-2, which was synthesized in the laboratory (named PSPD-2002 and PSPD-2003). For this, the animals were exposed for 35 days to the peptides at a concentration of 40 µg/L and different toxicity biomarkers were assessed. Our data indicated that the peptides were able to induce anxiety-like behavior in the open field test and increased acetylcholinesterase (AChE) activity. The biometric evaluation also revealed that the animals exposed to the peptides displayed alterations in the pattern of growth/development. Furthermore, the increased activity of superoxide dismutase (SOD) and catalase (CAT) enzymes were accompanied by increased levels of malondialdehyde (MDA), reactive oxygen species (ROS) and hydrogen peroxide (H₂O₂), which suggests a redox imbalance induced by SARS-CoV-2 spike protein peptides. Moreover, molecular docking analysis suggested a strong interaction of the peptides with the enzymes AChE, SOD and CAT, allowing us to infer that the observed effects are related to the direct action of the peptides on the functionality of these enzymes. Consequently, our study provided evidence that the presence of SARS-CoV-2 viral particles in the freshwater ecosystems offer a health risk to fish and other aquatic organisms.

Progress and Challenges Toward Generation and Maintenance of Long-Lived Memory T Lymphocyte Responses During COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the coronavirus disease 2019 (COVID-19) pandemic is a serious global threat until we identify the effective preventive and therapeutic strategies. SARS-CoV-2 infection is characterized by various immunopathological consequences including lymphocyte activation and dysfunction, lymphopenia, cytokine storm, increased level of neutrophils, and depletion and exhaustion of lymphocytes. Considering the low level of antibody-mediated protection during coronavirus infection, understanding the role of T cell for long-term protection is decisive. Both CD4⁺ and CD8⁺ T cell response is imperative for cell-mediated immune response during COVID-19. However, the level of CD8⁺ T cell response reduced to almost half as compared to CD4⁺ after 6 months of infection. The long-term protection is mediated via generation of immunological memory response during COVID-19. The presence of memory CD4⁺ T cells in all the severely infected and recovered individuals shows that the memory response is predominated by CD4⁺ T cells. Prominently, the antigen-specific CD4⁺ and CD8⁺ T cells are specifically observed during day 0 to day 28 in COVID-19-vaccinated individuals. However, level of antigen-specific T memory cells in COVID-19-vaccinated individuals defines the long-term protection against forthcoming outbreaks of SARS-CoV-2.

Expression analysis of IFNAR1 and TYK2 transcripts in COVID-19 patients

As a member of JAK family of non-receptor tyrosine kinases, TYK2 has a crucial role in regulation of immune responses. This protein has a crucial role in constant expression of IFNAR1 on surface of cells and initiation of type I IFN signaling. In the current study, we measured expression of IFNAR1 and TYK2 levels in venous blood samples of COVID-19 patients and matched controls. TYK2 was significantly down-regulated in male patients compared with male controls (RME = 0.34, P value = 0.03). Though, levels of TYK2 were not different between female cases and female controls, or between ICU-admitted and non-ICU-admitted cases. Expression of IFNAR1 was not different either between COVID-19 cases and controls or between patients required ICU admission and non-ICU-admitted cases. However, none of these transcripts can properly diffrentiate COVID-19 cases from controls or separate patients based on disease severity. The current study proposes down-regulation of TYK2 as a molecular mechanism for incapacity of SARS-CoV-2 in induction of a competent IFN response.

Cytokine Elevation in Severe COVID-19 From Longitudinal Proteomics Analysis: Comparison With Sepsis

Introduction

Coronavirus disease 2019 (COVID-19) is a new viral disease. Uncontrolled inflammation called “cytokine storm” is reported to contribute to disease pathogenesis as well as sepsis. We aimed to identify cytokines related to the pathogenesis of COVID-19 through a proteomics analysis of 1463 plasma proteins, validate these cytokines, and compare them with sepsis.

Materials and Methods

In a derivation cohort of 306 patients with COVID-19, 1463 unique plasma proteins were measured on days 1, 4, and 8. Cytokines associated with disease severity and prognosis were derived. In a validation cohort of 62 COVID-19 patients and 38 sepsis patients treated in the intensive care unit [ICU], these derived cytokines were measured on days 1 (day of ICU admission), 2-3, and 6-8 (maximum: 3 time points/patient). Derived cytokines were compared with healthy controls and between COVID-19 and sepsis patients, and the associations with prognosis were evaluated. The time to wean off mechanical ventilation (MV) was evaluated only for COVID-19.

Results

IL-6, amphiregulin, and growth differentiation factor (GDF)-15 were associated with disease severity and prognosis in the derivation cohort. In the validation cohort, IL-6 and GDF-15 were elevated in COVID-19 and sepsis on day 1, and the levels of these cytokines were higher in sepsis than in COVID-19. IL-6 and GDF-15 were associated with prognosis in sepsis. Cox proportional hazards model with time as a dependent covariate showed a significant relationship between plasma GDF-15 level and time to wean off MV (hazard ratio, 0.549 [95% confidence level, 0.382–0.789]). The GDF-15 level at ICU admission predicted late recovery.

Conclusion

GDF-15 and IL-6 derived from proteomics analysis were related with disease severity of COVID-19. Their values were higher in sepsis than in COVID-19 and were associated with prognosis in sepsis. In COVID-19 patients treated in the ICU, GDF-15 was associated with the time to wean off MV and better predicted late recovery.

Exhausted NK cells and cytokine storms in COVID-19: Whether NK cell therapy could be a therapeutic choice

The global outbreak of coronavirus-2019 (COVID-19) still claims more lives daily around the world due to the lack of a definitive treatment and the rapid tendency of virus to mutate, which even jeopardizes vaccination efficacy. At the forefront battle against SARS-CoV-2, an effective innate response to the infection has a pivotal role in the initial control and treatment of disease. However, SARS-CoV-2 subtly interrupts the equations of immune responses, disrupting the cytolytic antiviral effects of NK cells, while seriously activating infected macrophages and other immune cells to induce an unleashed "cytokine storm", a dangerous and uncontrollable inflammatory response causing life-threatening symptoms in patients. Notably, the NK cell exhaustion with ineffective cytolytic function against the sources of exaggerated cytokine release, acts as an Achilles' heel which exacerbates the severity of COVID-19. Given this, approaches that improve NK cell cytotoxicity may benefit treatment protocols. As a suggestion, adoptive transfer of NK or CAR-NK cells with proper cytotolytic potentials and the lowest capacity of cytokine-release (for example CD56^dim NK cells brightly express activating receptors), to severe COVID-19 patients may provide an effective cure especially in cases suffering from cytokine storms. More intriguingly, the ongoing evidence for persistent clonal expansion of NK memory cells characterized by an activating phenotype in response to viral infections, can benefit the future studies on vaccine development and adoptive NK cell therapy in COVID-19. Whether vaccinated volunteers or recovered patients can also be considered as suitable candidates for cell donation could be the subject of future research.

Immunomonitoring of Monocyte and Neutrophil Function in Critically Ill Patients: From Sepsis and/or Trauma to COVID-19

Immune cells and mediators play a crucial role in the critical care setting but are understudied. This review explores the concept of sepsis and/or injury-induced immunosuppression and immuno-inflammatory response in COVID-19 and reiterates the need for more accurate functional immunomonitoring of monocyte and neutrophil function in these critically ill patients. in addition, the feasibility of circulating and cell-surface immune biomarkers as predictors of infection and/or outcome in critically ill patients is explored. It is clear that, for critically ill, one size does not fit all and that immune phenotyping of critically ill patients may allow the development of a more personalized approach with tailored immunotherapy for the specific patient. In addition, at this point in time, caution is advised regarding the quality of evidence of some COVID-19 studies in the literature.

COVID-19 pandemic: Insights into genetic susceptibility to SARS-CoV-2 and host genes implications on virus spread, disease severity and outcomes

The outbreak of the newly emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) all over the world has caused global public health emergencies, international concern and economic crises. The systemic SARS-CoV-2 disease (COVID-19) can lead to death through causing unrestrained cytokines-storm and subsequent pulmonary shutdown among the elderly and patients with pre-existing comorbidities. Additionally, in comparison with poor nations without primary health care services, in developed countries with advanced healthcare system we can witness higher number of infections per one million people. In this review, we summarize the latest studies on genes associated with SARS-CoV-2 pathogenesis and propose possible mechanisms of the virus replication cycle and its triggered signaling pathways to encourage researchers to investigate genetic and immune profiles of the disease and try strategies for its treatment. Our review shows that immune response in people with different genetic background might vary as African and then Asian populations have lowest number of affected cases compared with European and American nations. Considering SARS-CoV-2 pathogenesis, we put forward some potentially important genetic gateways to COVID-19 infection including genes involved in the entry and replication of SARS-CoV-2 and the regulation of host immune response which might represent explanation for its spread, severity, and morality. Finally, we suggest that genetic alterations within these gateways could be critical factors in influencing geographical discrepancies of the virus, so it is essential to fully study them and design appropriated and reliable therapeutic agents against COVID-19.

Data-driven multi-scale mathematical modeling of SARS-CoV-2 infection reveals heterogeneity among COVID-19 patients

Patients with coronavirus disease 2019 (COVID-19) often exhibit diverse disease progressions associated with various infectious ability, symptoms, and clinical treatments. To systematically and thoroughly understand the heterogeneous progression of COVID-19, we developed a multi-scale computational model to quantitatively understand the heterogeneous progression of COVID-19 patients infected with severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2). The model consists of intracellular viral dynamics, multicellular infection process, and immune responses, and was formulated using a combination of differential equations and stochastic modeling. By integrating multi-source clinical data with model analysis, we quantified individual heterogeneity using two indexes, i.e., the ratio of infected cells and incubation period. Specifically, our simulations revealed that increasing the host antiviral state or virus induced type I interferon (IFN) production rate can prolong the incubation period and postpone the transition from asymptomatic to symptomatic outcomes. We further identified the threshold dynamics of T cell exhaustion in the transition between mild-moderate and severe symptoms, and that patients with severe symptoms exhibited a lack of naïve T cells at a late stage. In addition, we quantified the efficacy of treating COVID-19 patients and investigated the effects of various therapeutic strategies. Simulations results suggested that single antiviral therapy is sufficient for moderate patients, while combination therapies and prevention of T cell exhaustion are needed for severe patients. These results highlight the critical roles of IFN and T cell responses in regulating the stage transition during COVID-19 progression. Our study reveals a quantitative relationship underpinning the heterogeneity of transition stage during COVID-19 progression and can provide a potential guidance for personalized therapy in COVID-19 patients.

Coronavirus disease 2019 (COVID-19) is currently destroying both lives and economies. However, patients infected with severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2) usually present heterogeneous and complicated progressions, such as different incubation periods (short and long), symptoms (asymptomatic and symptomatic) and severity (mild-moderate and severe). Currently, various clinical data and experimental data are available from different countries, which has great significance for integrating different types of data to comprehensively understand the diverse disease progression in COVID-19 patients and guide individual treatment strategies. Here, we developed a multi-scale computational model to describe the dynamical process of patients infected with SARS-CoV-2, including intracellular viral dynamics, multicellular infection process, and immune responses. By combining data integration, stochastic simulation and quantitative analysis based on the multi-scale mathematical model, we addressed an important question regarding how IFN response and T cell exhaustion quantitatively affect heterogeneous progression in patients with respect to incubation periods, symptoms and severity. Furthermore, the efficacy of various therapeutic strategies for treating COVID-19 patients with different severity degrees was evaluated and validated. The computational framework in this study can also be extended to explore the dynamical process of other coronavirus infections.

The multi-faceted roles of TGF-β in regulation of immunity to infection

Transforming Growth Factor-β is a potent regulator of the immune system, acting at every stage from thymic differentiation, population of the periphery, control of responsiveness, tissue repair and generation of memory. It is therefore a central player in the immune response to infectious pathogens, but its contribution is often clouded by multiple roles acting on different cells in time and space. Hence, context is all-important in understanding when TGF-β is beneficial or detrimental to the outcome of infection. In this review, a full range of infectious agents from viruses to helminth parasites are explored within this framework, drawing contrasts and general conclusions about the importance of TGF-β in these diseases.

Covid-19 and development of heart failure: mystery and truth

Coronavirus disease 2019 (Covid-19) is a novel worldwide pandemic caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). During Covid-19 pandemic, socioeconomic deprivation, social isolation, and reduced physical activities may induce heart failure (HF), destabilization, and cause more complications. HF appears as a potential hazard due to SARS-CoV-2 infection, chiefly in elderly patients with underlying comorbidities. In reality, the expression of cardiac ACE2 is implicated as a target point for SARS-CoV-2-induced acute cardiac injury. In SARS-CoV-2 infection, like other febrile illnesses, high blood viscosity, exaggerated pro-inflammatory response, multisystem inflammatory syndrome, and endothelial dysfunction-induced coagulation disorders may increase risk of HF development. Hypoxic respiratory failure, as in pulmonary edema, severe acute lung injury (ALI), and acute respiratory distress syndrome (ARDS) may affect heart hemodynamic stability due to the development of pulmonary hypertension. Indeed, Covid-19-induced HF could be through the development of cytokine storm, characterized by high proliferation pro-inflammatory cytokines. In cytokine storm-mediated cardiac dysfunction, there is a positive correlation between levels of pro-inflammatory cytokine and myocarditis-induced acute cardiac injury biomarkers. Therefore, Covid-19-induced HF is more complex and related from a molecular background in releasing pro-inflammatory cytokines to the neuro-metabolic derangements that together affect cardiomyocyte functions and development of HF. Anti-heart failure medications, mainly digoxin and carvedilol, have potent anti-SARS-CoV-2 and anti-inflammatory properties that may mitigate Covid-19 severity and development of HF. In conclusion, SARS-CoV-2 infection may lead to the development of HF due to direct acute cardiac injury or through the development of cytokine storms, which depress cardiomyocyte function and cardiac contractility. Anti-heart failure drugs, mainly digoxin and carvedilol, may attenuate severity of HF by reducing the infectivity of SARS-CoV-2 and prevent the development of cytokine storms in severely affected Covid-19 patients.

Neuropsychiatric Disorders and COVID-19: What We Know So Far

SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2) affects the central nervous system (CNS), which is shown in a significant number of patients with neurological events. In this study, an updated literature review was carried out regarding neurological disorders in COVID-19. Neurological symptoms are more common in patients with severe infection according to their respiratory status and divided into three categories: (1) CNS manifestations; (2) cranial and peripheral nervous system manifestations; and (3) skeletal muscle injury manifestations. Patients with pre-existing cerebrovascular disease are at a higher risk of admission to the intensive care unit (ICU) and mortality. The neurological manifestations associated with COVID-19 are of great importance, but when life-threatening abnormal vital signs occur in severely ill COVID-19 patients, neurological problems are usually not considered. It is crucial to search for new treatments for brain damage, as well as for alternative therapies that recover the damaged brain and reduce the inflammatory response and its consequences for other organs. In addition, there is a need to diagnose these manifestations as early as possible to limit long-term consequences. Therefore, much research is needed to explain the involvement of SARS-CoV-2 causing these neurological symptoms because scientists know zero about it.

Severe acute respiratory syndrome coronavirus 2 targeted antibodies cocktail and B cell receptor interplay: interventions to trigger vaccine development

Coronavirus disease-2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2 spread globally and creates an alarming situation. Following the SARS-CoV-2 paradigm, therapeutic efficacy is achieved via repurposing several antiviral, antibacterial, and antimalarial drugs. Innate and adaptive immune cells work close to combat infection through the intricate production of antibodies (Abs) and inflammatory cytokines. As an essential component of the immune system, Abs play an important role in eliminating viruses and maintaining homeostasis. B lymphocytes (B cells) are effector cells, stringent to produce neutralizing Abs to combat infection. After recognizing SARS-CoV-2 antigens by a surface receptor called B cell receptors (BCRs) on the plasma membrane, the BCRs transmembrane signal transduction and immune activation results in Ab production and development of immune memory. Thus, it ensures that plasma B cells can quickly start an intricate immune response to generate efficient protective Abs to clear the pathogen. Nevertheless, considering therapeutic challenges in the context of the new coronavirus pandemic, this review addresses the molecular mechanism of the immune activation and function of novel SARS-CoV-2 specific B cells in the production of SARS-CoV-2 specific Abs. Additionally, these studies highlighted the Ab-mediated pathogenesis, the intriguing role of nano-scale signaling subunits, non-structural proteins during COVID-19 infection, and structural insights of SARS-CoV-2 specific Abs.

Detection of SARS-CoV-2 Derived Small RNAs and Changes in Circulating Small RNAs Associated with COVID-19

Cleavage of double-stranded RNA is described as an evolutionary conserved host defense mechanism against viral infection. Small RNAs are the product and triggers of post transcriptional gene silencing events. Up until now, the relevance of this mechanism for SARS-CoV-2-directed immune responses remains elusive. Herein, we used high throughput sequencing to profile the plasma of active and convalescent COVID-19 patients for the presence of small circulating RNAs. The existence of SARS-CoV-2 derived small RNAs in plasma samples of mild and severe COVID-19 cases is described. Clusters of high siRNA abundance were discovered, homologous to the nsp2 3′-end and nsp4 virus sequence. Four virus-derived small RNA sequences have the size of human miRNAs, and a target search revealed candidate genes associated with ageusia and long COVID symptoms. These virus-derived small RNAs were detectable also after recovery from the disease. The additional analysis of circulating human miRNAs revealed differentially abundant miRNAs, discriminating mild from severe cases. A total of 29 miRNAs were reduced or absent in severe cases. Several of these are associated with JAK-STAT response and cytokine storm.

Immunodominant T-cell epitopes from the SARS-CoV-2 spike antigen reveal robust pre-existing T-cell immunity in unexposed individuals

The COVID-19 pandemic has revealed a range of disease phenotypes in infected patients with asymptomatic, mild, or severe clinical outcomes, but the mechanisms that determine such variable outcomes remain unresolved. In this study, we identified immunodominant CD8 T-cell epitopes in the spike antigen using a novel TCR-binding algorithm. The predicted epitopes induced robust T-cell activation in unexposed donors demonstrating pre-existing CD4 and CD8 T-cell immunity to SARS-CoV-2 antigen. The T-cell reactivity to the predicted epitopes was higher than the Spike-S1 and S2 peptide pools in the unexposed donors. A key finding of our study is that pre-existing T-cell immunity to SARS-CoV-2 is contributed by TCRs that recognize common viral antigens such as Influenza and CMV, even though the viral epitopes lack sequence identity to the SARS-CoV-2 epitopes. This finding is in contrast to multiple published studies in which pre-existing T-cell immunity is suggested to arise from shared epitopes between SARS-CoV-2 and other common cold-causing coronaviruses. However, our findings suggest that SARS-CoV-2 reactive T-cells are likely to be present in many individuals because of prior exposure to flu and CMV viruses.

Evaluation of expression of VDR-associated lncRNAs in COVID-19 patients

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been shown to cause serious health problems among them is the Acute Respiratory Distress syndrome (ARDS). Vitamin D receptor (VDR) signaling possibly partakes in the pathophysiology of this devastating complication.

METHODS

In the current project, we have appraised expression levels of VDR, CYP27B1 and a number of associated lncRNAs in the circulation of COVID-19 patients versus healthy subjects using real-time PCR method.

RESULTS

Expression of SNHG6 was considerably lower in COVID-19 patients compared with control subjects (Ratio of mean expression (RME) = 0.22, P value = 7.04E-05) and in both female and male COVID-19 patients compared with sex-matched unaffected individuals (RME = 0.32, P value = 0.04 and RME = 0.16, P value = 0.000679683, respectively). However, its expression was similar among ICU-hospitalized and non-ICU patients. Similarly, expression of SNHG16 was lower in in COVID-19 patients compared with controls (RME = 0.20, P value = 5.94E-05) and in both female and male patients compared with sex-matched controls (RME = 0.32, P value = 0.04 and RME = 0.14, P value = 0.000496435, respectively) with no significant difference among ICU-hospitalized and non-ICU hospitalized patients. Expression of VDR was lower in COVID-19 patients compared with controls (RME = 0.42, P value = 0.04) and in male patients compared with male controls (RME = 0.27, P value = 0.02). Yet, expression of VDR was statistically similar between female subgroups and between ICU-hospitalized and non-ICU hospitalized patients. Expression levels CYP27B, Linc00511 and Linc00346 were similar among COVID-19 patients and healthy subjects or between their subgroups. Significant correlations have been detected between expression levels of VDR, CYP27B and SNHG6, SNHG16, Linc00511 and Linc00346 lncRNAs both among COVID-19 patients and among healthy controls with the most significant ones being SNHG6 and SNHG16 (r = 0.74, P value = 3.26e-17 and r = 0.81, P = 1.54e-22, respectively).

CONCLUSION

Combination of transcript levels of VDR, CYP27B and SNHG6, SNHG16, Linc00511 and Linc00346 could differentiate patients from controls with AUC = 0.76, sensitivity = 0.62 and specificity = 0.81. The current data potentiate SNHG6, SNHG16 and VDR as possible contributors in COVID-19 infection but not in the severity of ARDS.

Relative expression of proinflammatory molecules in COVID-19 patients who manifested disease severities

Aggressive immune response, due to overexpressed proinflammatory molecules, has been characterized in coronavirus disease 2019 (COVID‐19) patients. Some of those mediators have a dual and opposite role on immune systems at play behind differential disease severities. We investigated the expression of some cytokines and chemokines in COVID‐19 patients in Bangladesh. We diagnosed the patients by detecting severe acute respiratory syndrome coronavirus 2 RNA in nasal swab samples by the real‐time RT‐PCR method. Thirty adult patients were preselected based on their disease severities and grouped into mild, moderate, and severe cases. Nine healthy volunteers participated in this study as a control. Relative expression of nine cytokines/chemokine in total leukocytes was semi‐quantified in SYBRgreen‐based real‐time quantitative reverse‐transcriptase polymerase chain reaction. We performed statistical tests on transformed log data using SPSS 24.0. At the onset of symptoms (Day 1), angiotensin‐converting enzyme 2 (ACE2) (p < 0.05) and interleukin (IL)‐6 (p > 0.05) were upregulated in all COVID‐19 groups, although the expression levels did not significantly correlate with disease severities. However, expressions of IL‐6, monocyte chemotactic protein‐1, macrophage inflammatory protein‐1α, tumor necrosis factor‐α (TNF‐α), RANTES (regulated upon activation, normal T cell expressed and secreted), and ACE2, on Day 14, were positively correlated with disease severities. Relative viral load at Day 1 showed no significant correlation with cytokine expression but had a significant positive correlation with RANTES and ACE2 expression on Day 14 (p < 0.05). Male patients had a higher level of IL‐6 than female patients on Day 1 (p < 0.05). All COVID‐19 patients showed upregulated cytokines and chemokines on Day 14 compared to Day 1 except TNF‐α. Female patients had a higher expression of ACE2 and IL‐12 on Day 14. Upregulated cytokines/chemokines at the convalescent stage, especially IL‐6, may help in targeting anticytokine therapy in post‐COVID‐19 patients' management.

Immunomodulation: Immunoglobulin Preparations Suppress Hyperinflammation in a COVID-19 Model via FcγRIIA and FcαRI

The rapid spread of SARS-CoV-2 has induced a global pandemic. Severe forms of COVID-19 are characterized by dysregulated immune response and "cytokine storm". The role of IgG and IgM antibodies in COVID-19 pathology is reasonably well studied, whereas IgA is neglected. To improve clinical outcome of patients, immune modulatory drugs appear to be beneficial. Such drugs include intravenous immunoglobulin preparations, which were successfully tested in severe COVID-19 patients. Here we established a versatile in vitro model to study inflammatory as well as anti-inflammatory processes by therapeutic human immunoglobulins. We dissect the inflammatory activation on neutrophil-like HL60 cells, using an immune complex consisting of latex beads coated with spike protein of SARS-CoV-2 and opsonized with specific immunoglobulins from convalescent plasma. Our data clarifies the role of Fc-receptor-dependent phagocytosis via IgA-FcαRI and IgG-FcγR for COVID-19 disease followed by cytokine release. We show that COVID-19 associated inflammation could be reduced by addition of human immunoglobulin preparations (IVIG and trimodulin), while trimodulin elicits stronger immune modulation by more powerful ITAMi signaling. Besides IgG, the IgA component of trimodulin in particular, is of functional relevance for immune modulation in this assay setup, highlighting the need to study IgA mediated immune response.

Reinforcing our defense or weakening the enemy? A comparative overview of defensive and offensive strategies developed to confront COVID-19

Developing effective strategies to confront coronavirus disease 2019 (COVID-19) has become one of the greatest concerns of the scientific community. In addition to the vast number of global mortalities due to COVID-19, since its outbreak, almost every aspect of human lives has changed one way or another. In the present review, various defensive and offensive strategies developed to confront COVID-19 are illustrated. The Administration of immune-boosting micronutrients/agents, as well as the inhibition of the activity of incompetent gatekeepers, including some host cell receptors (e.g. ACE2) and proteases (e.g. TMPRSS2), are some efficient defensive strategies. Antibody/phage therapies and specifically vaccines also play a prominent role in the enhancement of host defense against COVID-19. Nanotechnology, however, can considerably weaken the virulence of SARS-CoV-2, utilizing fake cellular locks (compounds mimicking cell receptors) to block the viral keys (spike proteins). Generally, two strategies are developed to interfere with the binding of spike proteins to the host cell receptors, either utilizing fake cellular locks to block the viral keys or utilizing fake viral keys to block the cellular locks. Due to their evolutionary conserved nature, viral enzymes, including 3CLpro, PLpro, RdRp, and helicase are highly potential targets for drug repurposing strategy. Thus, various steps of viral replication/transcription can effectively be blocked by their inhibition, leading to the elimination of SARS-CoV-2. Moreover, RNA decoy and CRISPR technologies likely offer the best offensive strategies after viral entry into the host cells, inhibiting the viral replication/assembly in the infected cells and substantially reducing the quantity of viral progeny.

An overview of some potential immunotherapeutic options against COVID-19

After the advent of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) in the late 2019, the resulting severe and pernicious syndrome (COVID-19) immediately was deployed all around the world. To date, despite relentless efforts to control the disease by drug repurposing, there is no approved specific therapy for COVID-19. Given the role of innate and acquired immune components in the control and elimination of viral infections and inflammatory mutilations during SARS-CoV2 pathogenesis, immunotherapeutic strategies appear to be beneficent. Passive immunotherapies such as convalescent plasma, which has received much attention especially in severe cases, as well as suppressing inflammatory cytokines, interferon administration, inhibition of kinases and complement cascade, virus neutralization with key engineered products, cell-based therapies, immunomodulators and anti-inflammatory drugs are among the key immunotherapeutic approaches to deal with COVID-19, which is discussed in this review. Also, details of leading COVID-19 vaccine candidates as the most potent immunotherapy have been provided. However, despite salient improvements, there is still a lack of completely assured vaccines for universal application. Therefore, adopting proper immunotherapies according to the cytokine pattern and involved immune responses, alongside engineered biologics specially ACE2-Fc to curb SARS-CoV2 infection until achieving a tailored vaccine is probably the best strategy to better manage this pandemic. Therefore, gaining knowledge about the mechanism of action, potential targets, as well as the effectiveness of immune-based approaches to confront COVID-19 in the form of a well-ordered review study is highly momentous.

Germinal Center and Extrafollicular B Cell Responses in Vaccination, Immunity, and Autoimmunity

Activated B cells participate in either extrafollicular (EF) or germinal center (GC) responses. Canonical responses are composed of a short wave of plasmablasts (PBs) arising from EF sites, followed by GC producing somatically mutated memory B cells (MBC) and long-lived plasma cells. However, somatic hypermutation (SHM) and affinity maturation can take place at both sites, and a substantial fraction of MBC are produced prior to GC formation. Infection responses range from GC responses that persist for months to persistent EF responses with dominant suppression of GCs. Here, we review the current understanding of the functional output of EF and GC responses and the molecular switches promoting them. We discuss the signals that regulate the magnitude and duration of these responses, and outline gaps in knowledge and important areas of inquiry. Understanding such molecular switches will be critical for vaccine development, interpretation of vaccine efficacy and the treatment for autoimmune diseases.

Clinical and demographic characteristics of patients with COVID-19 infection: Statistics from a single hospital in Iran

Coronavirus disease 2019 (COVID-19) has caused a global pandemic in early 2020. This infectious disorder has a heterogeneous course ranging from asymptomatic disorder to a critical situation needing intensive cares. In the current study, we present a report of affected patients admitted in a single hospital in Iran. Eighty-two hospitalized patients with COVID-19 were assessed. Demographic, clinical, and paraclinical parameters were gathered and statistically analyzed. The median age (IQR) of the patients was 57.32 (45.75, 70) years. At primary evaluation, fever was present in 45.12% of the affected individuals. The most common clinical symptoms were dyspnea (81.71%) and cough (65.85%). Totally, 12 (14.63%) and 14 (17.07%) of patients had low and high WBC counts, respectively. Lymphopenia was detected in 36 (43.9%) of patients, while 6 (7.32%) of patients had lymphocytosis. High levels of Il-6 were detected in 4 (4.88%) of patients. CRP levels were elevated in 69 (84.1%) of patients. The median (IQR) of hospitalization was 7 (5, 9) days. Totally, 26 patients (31%) were hospitalized in ICU. All patients were discharged with good health conditions except for one patient who died. The current study shows the heterogeneous clinical manifestations and paraclinical parameters of COVID-19 patients.

A study of differential circRNA and lncRNA expressions in COVID-19-infected peripheral blood

To conquer the worldwide outbreak of COVID-19 virus, a large number of studies have been carried out on COVID-19 infection, transmission and treatment. However, few studies have been conducted from the perspectives of circRNA and lncRNA, which are known to be involved in regulating many life activities, such as immune tolerance and immune escapes, and hence may provide invaluable information in the emerging COVID-19 infection and recurrence. Moreover, exosomes has been reported to play an important role in COVID-19 recurrence, and thus may interact with the expression of circRNA and lncRNA. In this work, we sequenced circRNA, lncRNA and mRNA from recurrent COVID-19 patients and healthy people, and compared the differences. GO and KEGG enrichment analysis show that differentially expressed circRNA and lncRNA are mainly involved in the regulation of host cell cycle, apoptosis, immune inflammation, signaling pathway and other processes. The comparison to exosomes related databases shows that there are 114 differentially expressed circRNA, and 10 differentially expressed lncRNA related to exosomes. These studies provide reference for exploring circRNA and lncRNA to study the infection mechanism of COVID-19, their diagnostic and therapeutic values, as well as the possibility to employ them as biomarkers.

In Silico Mining of Terpenes from Red-Sea Invertebrates for SARS-CoV-2 Main Protease (Mpro) Inhibitors

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent for the COVID-19 pandemic, which generated more than 1.82 million deaths in 2020 alone, in addition to 83.8 million infections. Currently, there is no antiviral medication to treat COVID-19. In the search for drug leads, marine-derived metabolites are reported here as prospective SARS-CoV-2 inhibitors. Two hundred and twenty-seven terpene natural products isolated from the biodiverse Red-Sea ecosystem were screened for inhibitor activity against the SARS-CoV-2 main protease (Mpro) using molecular docking and molecular dynamics (MD) simulations combined with molecular mechanics/generalized Born surface area binding energy calculations. On the basis of in silico analyses, six terpenes demonstrated high potency as Mpro inhibitors with ΔGbinding ≤ -40.0 kcal/mol. The stability and binding affinity of the most potent metabolite, erylosides B, were compared to the human immunodeficiency virus protease inhibitor, lopinavir. Erylosides B showed greater binding affinity towards SARS-CoV-2 Mpro than lopinavir over 100 ns with ΔGbinding values of -51.9 vs. -33.6 kcal/mol, respectively. Protein-protein interactions indicate that erylosides B biochemical signaling shares gene components that mediate severe acute respiratory syndrome diseases, including the cytokine- and immune-signaling components BCL2L1, IL2, and PRKC. Pathway enrichment analysis and Boolean network modeling were performed towards a deep dissection and mining of the erylosides B target-function interactions. The current study identifies erylosides B as a promising anti-COVID-19 drug lead that warrants further in vitro and in vivo testing.

Clinical significance of measuring serum cytokine levels as inflammatory biomarkers in adult and pediatric COVID-19 cases: A review

Coronavirus disease 2019 (COVID-19) is a rapidly evolving infectious/inflammatory disorder which has turned into a global pandemic. With severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as its etiologic agent, severe COVID-19 cases usually develop uncontrolled inflammatory responses and cytokine storm-like syndromes. Measuring serum levels of pro-inflammatory cytokines (e.g., IL-6 and others) as inflammatory biomarkers may have several potential applications in the management of COVID-19, including risk assessment, monitoring of disease progression, determination of prognosis, selection of therapy and prediction of response to treatment. This is especially true for pediatric patients with COVID-19 associated Kawasaki-like disease and similar syndromes. In this report, we review the current knowledge of COVID-19 associated cytokines, their roles in host immune and inflammatory responses, the clinical significance and utility of cytokine immunoassays in adult and pediatric COVID-19 patients, as well as the challenges and pitfalls in implementation and interpretation of cytokine immunoassays. Given that cytokines are implicated in different immunological disorders and diseases, it is challenging to interpret the multiplex cytokine data for COVID-19 patients. Also, it should be taken into consideration that biological and technical variables may affect the commutability of cytokine immunoassays and enhance complexity of cytokine immunoassay interpretation. It is recommended that the same method, platform and laboratory should be used when monitoring differences in cytokine levels between groups of individuals or for the same individual over time. It may be important to correlate cytokine profiling data with the SARS-CoV-2 nucleic acid amplification testing and imaging observations to make an accurate interpretation of the inflammatory status and disease progression in COVID-19 patients.

Understanding COVID-19 in Wuhan From the Perspective of Cold-Dampness: Clinical Evidences and Mechanisms

Traditional Chinese medicine (TCM) has played a significant role in the treatment of coronavirus disease 2019 (COVID-19) in Wuhan City. During the epidemic, Academician Tong Xiaolin suggested a close association of COVID-19 with cold-dampness, an etiological factor in TCM, by summarizing the characteristics of the COVID-19 patients in Wuhan. and the theory of Cold-dampness Plague was proposed. Based on the Cold-dampness Plague theory, a series of TCM drugs, such as Huoxiang Zhengqi Dropping Pills, Lianhua Qingwen Granules Hanshiyi Formula, and Tongzhi Granule were developed for the different stages, namely mild, moderate, severe, recovery, of the COVID-19. In addition, clinical evidences were obtained through randomized clinical trials or retrospective cohort studies. The Anti-SARS-CoV-2 mechanism of the TCM prescriptions were then summarized from the four aspects: targeting the ACE2 and 3CLPro, targeting cytokines, targeting acute immune responses to SARS-CoV-2, and targeting pulmonary fibrosis. Despite the clinical efficacy and therapeutic pharmacology speculation, more studies such as large-scale randomized clinical trials, cell and animal experiments are needed to further verify the theory of the Cold-dampness Plague in COVID-19 patients.

Cytokine and Chemokine Levels in Coronavirus Disease 2019 Convalescent Plasma

BACKGROUND

The efficacy of coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) is primarily ascribed as a source of neutralizing anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. However, the composition of other immune components in CCP and their potential roles remain largely unexplored. This study aimed to describe the composition and concentrations of plasma cytokines and chemokines in eligible CCP donors.

METHODS

A cross-sectional study was conducted among 20 prepandemic healthy blood donors without SARS-CoV-2 infection and 140 eligible CCP donors with confirmed SARS-CoV-2 infection. Electrochemiluminescence detection-based multiplexed sandwich immunoassays were used to quantify plasma cytokine and chemokine concentrations (n = 35 analytes). A SARS-CoV-2 microneutralization assay was also performed. Differences in the percentage of detection and distribution of cytokine and chemokine concentrations were examined by categorical groups using Fisher's exact and Wilcoxon rank-sum tests, respectively.

RESULTS

Among CCP donors (n = 140), the median time since molecular diagnosis of SARS-CoV-2 was 44 days (interquartile range = 38-50) and 9% (n = 12) were hospitalized due to COVID-19. Compared with healthy blood donor controls, CCP donors had significantly higher plasma levels of interferon (IFN)-γ, interleukin (IL)-10, IL-15, IL-21, and macrophage-inflammatory protein-1, but lower levels of IL-1RA, IL-8, IL-16, and vascular endothelial growth factor-A (P < .0014). The distributions of plasma levels of IL-8, IL-15, and IFN-inducible protein-10 were significantly higher among CCP donors with high (≥160) versus low (<40) anti-SARS-CoV-2 neutralizing antibody titers (P < .0014). The median levels of IL-6 were significantly higher among CCP donors who were hospitalized versus nonhospitalized (P < .0014).

CONCLUSIONS

Heterogeneity in cytokine and chemokine composition of CCP suggests there is a different inflammatory state among the CCP donors compared with SARS-CoV-2 naive, healthy blood donors.

Cytokine storm induced by SARS-CoV-2 infection: The spectrum of its neurological manifestations

The new coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can trigger a hyperinflammatory state characterized by elevated cytokine levels known as hypercytokinemia or cytokine storm, observed most often in severe patients. Though COVID-19 is known to be a primarily respiratory disease, neurological complications affecting both the central and peripheral nervous systems have also been reported. This review discusses potential routes of SARS-CoV-2 neuroinvasion and pathogenesis, summarizes reported neurological sequelae of COVID-19, and examines how aberrant cytokine levels may precipitate these complications. Clarification of the pathogenic mechanisms of SARS-CoV-2 is needed to encourage prompt diagnosis and optimized care. In particular, identifying the presence of cytokine storm in patients with neurological COVID-19 manifestations will facilitate avenues for treatment. Future investigations into aberrant cytokine levels in COVID-19 patients with neurological symptoms as well as the efficacy of cytokine storm-targeting treatments will be critical in elucidating the pathogenic mechanisms and effective treatments of COVID-19.

Prognostic bioindicators in severe COVID-19 patients

Background

Severe acute respiratory syndrome caused by novel coronavirus 2 (SARS-CoV-2) emerged in Wuhan (China) in December 2019. Here we evaluated a panel of biomarkers to phenotype patients and to define the role of immuno-inflammatory mediators as biomarkers of severity.

Materials and methods

Serum samples were obtained from 24 COVID-19 patients on admission to hospital, before any treatment or infusion of intravenous steroids or invasive ventilation. KL-6 IL-6 and C-peptide were measured by chemiluminescent enzyme immunoassay. IL-6 assay was validated for accuracy and precision. The validity of variables used to distinguish severe from mild-to-moderate patients was assessed by areas under curves (AUC) of the receiver operating characteristic (ROC) and logistic regression was performed to combine parameters of the two groups.

Results

In the severe group, IL-6, CRP and KL-6 concentrations were significantly higher than in mild-to-moderate patients. KL-6, IL-6 and CRP concentrations were directly correlated with each other. ROC curve analysis of the logistic regression model including IL-6, KL-6 and CRP showed the best performance with an AUC of 0.95.

Conclusions

Besides corroborating previous reports of over-expression of IL-6 in severe COVID-19 patients requiring mechanical ventilation, analytical determination of other mediators showed that IL-6 concentrations were correlated with those of KL-6 and CRP. The combination of these three prognostic bioindicators made it possible to distinguish severe COVID-19 patients with poor prognosis from mild-to-moderate patients.

Interplay of Antibody and Cytokine Production Reveals CXCL13 as a Potential Novel Biomarker of Lethal SARS-CoV-2 Infection

The SARS-CoV-2 pandemic is impacting the global population. This study was designed to assess the interplay of antibodies with the cytokine response in SARS-CoV-2 patients. We demonstrate that significant levels of anti-SARS-CoV-2 antibody to receptor binding domain (RBD), nucleocapsid, and spike S1 subunit of SARS-CoV-2 develop over the first 10 to 20 days of infection. The majority of patients produced antibodies against all three antigens (219/255 SARS-CoV-2+ patient specimens, 86%), suggesting a broad response to viral proteins. Antibody levels to SARS-CoV-2 antigens were different based on patient mortality, sex, blood type, and age. Analyses of these findings may help explain variation in immunity between these populations. To better understand the systemic immune response, we analyzed the levels of 20 cytokines by SARS-CoV-2 patients throughout infection. Cytokine analysis of SARS-CoV-2+ patients exhibited increases in proinflammatory markers (interleukin 6 [IL-6], IL-8, IL-18, and gamma interferon [IFN-γ]) and chemotactic markers (IP-10 and eotaxin) relative to healthy individuals. Patients who succumbed to infection produced decreased IL-2, IL-4, IL-12, RANTES, tumor necrosis factor alpha (TNF-α), GRO-α, and MIP-1α relative to patients who survived infection. We also observed that the chemokine CXCL13 was particularly elevated in patients who succumbed to infection. CXCL13 is involved in B cell activation, germinal center development, and antibody maturation, and we observed that CXCL13 levels in blood trended with anti-SARS-CoV-2 antibody levels. Furthermore, patients who succumbed to infection produced high CXCL13 and had a higher ratio of nucleocapsid to RBD antibodies. This study provides insights into SARS-CoV-2 immunity implicating the magnitude and specificity of response in relation to patient outcomes.IMPORTANCE The SARS-CoV-2 pandemic is continuing to impact the global population, and knowledge of the immune response to COVID-19 is still developing. This study assesses the interplay of different parts of the immune system during COVID-19 disease. We demonstrate that COVID-19 patients produce antibodies to three proteins of the COVID-19 virus (SARS-CoV-2) and identify many other immunological proteins that are involved during infection. The data suggest that one of these proteins (CXCL13) may be a novel biomarker for severe COVID-19 that can be readily measured in blood. This information combined with our broad-scale analysis of immune activity during COVID-19 provides new information on the immunological response throughout the course of disease and identifies a novel potential marker for assessing disease severity.

Serum CCL17 level becomes a predictive marker to distinguish between mild/moderate and severe/critical disease in patients with COVID-19

COVID-19, a novel coronavirus-related illness, has spread worldwide. Patients with apparently mild/moderate symptoms can suddenly develop severe pneumonia. Therefore, almost all COVID-19 patients require hospitalization, which can reduce limited medical resources in addition to overwhelming medical facilities. To identify predictive markers for the development of severe pneumonia, a comprehensive analysis of serum chemokines and cytokines was conducted using serial serum samples from COVID-19 patients. The expression profiles were analyzed along the time axis. Serum samples of common diseases were enrolled from a BioBank to confirm the usefulness of predictive markers. Five factors, IFN-λ3, IL-6, IP-10, CXCL9, and CCL17, were identified as predicting the onset of severe/critical symptoms. The factors were classified into two categories. Category A included IFN-λ3, IL-6, IP-10, and CXCL9, and their values surged and decreased rapidly before the onset of severe pneumonia. Category B included CCL17, which provided complete separation between the mild/moderate and the severe/critical groups at an early phase of SARS-CoV-2 infection. The five markers provided a high predictive value (area under the receiver operating characteristic curve (AUROC): 0.9-1.0, p < 0.001). Low expression of CCL17 was specifically observed in pre-severe COVID-19 patients compared with other common diseases, and the predictive ability of CCL17 was confirmed in validation samples of COVID-19. The factors identified could be promising prognostic markers to distinguish between mild/moderate and severe/critical patients, enabling triage at an early phase of infection, thus avoiding overwhelming medical facilities.

The Role of MSC Therapy in Attenuating the Damaging Effects of the Cytokine Storm Induced by COVID-19 on the Heart and Cardiovascular System

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has led to 47 m infected cases and 1. 2 m (2.6%) deaths. A hallmark of more severe cases of SARS-CoV-2 in patients with acute respiratory distress syndrome (ARDS) appears to be a virally-induced over-activation or unregulated response of the immune system, termed a "cytokine storm," featuring elevated levels of pro-inflammatory cytokines such as IL-2, IL-6, IL-7, IL-22, CXCL10, and TNFα. Whilst the lungs are the primary site of infection for SARS-CoV-2, in more severe cases its effects can be detected in multiple organ systems. Indeed, many COVID-19 positive patients develop cardiovascular complications, such as myocardial injury, myocarditis, cardiac arrhythmia, and thromboembolism, which are associated with higher mortality. Drug and cell therapies targeting immunosuppression have been suggested to help combat the cytokine storm. In particular, mesenchymal stromal cells (MSCs), owing to their powerful immunomodulatory ability, have shown promise in early clinical studies to avoid, prevent or attenuate the cytokine storm. In this review, we will discuss the mechanistic underpinnings of the cytokine storm on the cardiovascular system, and how MSCs potentially attenuate the damage caused by the cytokine storm induced by COVID-19. We will also address how MSC transplantation could alleviate the long-term complications seen in some COVID-19 patients, such as improving tissue repair and regeneration.

Role of Host Immune and Inflammatory Responses in COVID-19 Cases with Underlying Primary Immunodeficiency: A Review

Coronavirus disease 2019 (COVID-19) has spread rapidly and become a pandemic. Caused by a novel human coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), severe COVID-19 is characterized by cytokine storm syndromes due to innate immune activation. Primary immunodeficiency (PID) cases represent a special patient population whose impaired immune system might make them susceptible to severe infections, posing a higher risk to COVID-19, but this could also lead to suppressed inflammatory responses and cytokine storm. It remains an open question as to whether the impaired immune system constitutes a predisposing or protective factor for PID patients when facing SARS-CoV-2 infection. After literature review, it was found that, similar to other patient populations with different comorbidities, PID patients may be susceptible to SARS-CoV-2 infection. Their varied immune status, however, may lead to different disease severity and outcomes after SARS-CoV-2 infection. PID patients with deficiency in antiviral innate immune signaling [eg, Toll-like receptor (TLR)3, TLR7, or interferon regulatory factor 7 (IRF7)] or interferon signaling (IFNAR2) may be linked to severe COVID-19. Because of its anti-infection, anti-inflammatory, and immunomodulatory effects, routine intravenous immunoglobulin therapy may provide some protective effects to the PID patients.

Targeting Crucial Host Factors of SARS-CoV-2

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide since its first incidence in Wuhan, China, in December 2019. Although the case fatality rate of COVID-19 appears to be lower than that of SARS and Middle East respiratory syndrome (MERS), the higher transmissibility of SARS-CoV-2 has caused the total fatality to surpass other viral diseases, reaching more than 1 million globally as of October 6, 2020. The rate at which the disease is spreading calls for a therapy that is useful for treating a large population. Multiple intersecting viral and host factor targets involved in the life cycle of the virus are being explored. Because of the frequent mutations, many coronaviruses gain zoonotic potential, which is dependent on the presence of cell receptors and proteases, and therefore the targeting of the viral proteins has some drawbacks, as strain-specific drug resistance can occur. Moreover, the limited number of proteins in a virus makes the number of available targets small. Although SARS-CoV and SARS-CoV-2 share common mechanisms of entry and replication, there are substantial differences in viral proteins such as the spike (S) protein. In contrast, targeting cellular factors may result in a broader range of therapies, reducing the chances of developing drug resistance. In this Review, we discuss the role of primary host factors such as the cell receptor angiotensin-converting enzyme 2 (ACE2), cellular proteases of S protein priming, post-translational modifiers, kinases, inflammatory cells, and their pharmacological intervention in the infection of SARS-CoV-2 and related viruses.

SARS-CoV-2 triggers inflammatory responses and cell death through caspase-8 activation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to respiratory illness and multi-organ failure in critically ill patients. Although the virus-induced lung damage and inflammatory cytokine storm are believed to be directly associated with coronavirus disease 2019 (COVID-19) clinical manifestations, the underlying mechanisms of virus-triggered inflammatory responses are currently unknown. Here we report that SARS-CoV-2 infection activates caspase-8 to trigger cell apoptosis and inflammatory cytokine processing in the lung epithelial cells. The processed inflammatory cytokines are released through the virus-induced necroptosis pathway. Virus-induced apoptosis, necroptosis, and inflammation activation were also observed in the lung sections of SARS-CoV-2-infected HFH4-hACE2 transgenic mouse model, a valid model for studying SARS-CoV-2 pathogenesis. Furthermore, analysis of the postmortem lung sections of fatal COVID-19 patients revealed not only apoptosis and necroptosis but also massive inflammatory cell infiltration, necrotic cell debris, and pulmonary interstitial fibrosis, typical of immune pathogenesis in the lung. The SARS-CoV-2 infection triggered a dual mode of cell death pathways and caspase-8-dependent inflammatory responses may lead to the lung damage in the COVID-19 patients. These discoveries might assist the development of therapeutic strategies to treat COVID-19.

SARS-CoV-2 Infection: A Role for S1P/S1P Receptor Signaling in the Nervous System?

The recent coronavirus disease (COVID-19) is still spreading worldwide. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the virus responsible for COVID-19, binds to its receptor angiotensin-converting enzyme 2 (ACE2), and replicates within the cells of the nasal cavity, then spreads along the airway tracts, causing mild clinical manifestations, and, in a majority of patients, a persisting loss of smell. In some individuals, SARS-CoV-2 reaches and infects several organs, including the lung, leading to severe pulmonary disease. SARS-CoV-2 induces neurological symptoms, likely contributing to morbidity and mortality through unknown mechanisms. Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid with pleiotropic properties and functions in many tissues, including the nervous system. S1P regulates neurogenesis and inflammation and it is implicated in multiple sclerosis (MS). Notably, Fingolimod (FTY720), a modulator of S1P receptors, has been approved for the treatment of MS and is being tested for COVID-19. Here, we discuss the putative role of S1P on viral infection and in the modulation of inflammation and survival in the stem cell niche of the olfactory epithelium. This could help to design therapeutic strategies based on S1P-mediated signaling to limit or overcome the host-virus interaction, virus propagation and the pathogenesis and complications involving the nervous system.

Single Virus Targeting Multiple Organs: What We Know and Where We Are Heading?

COVID-19 caused by SARS-CoV-2 has already infected more than 6. 3 million people worldwide as of 1st June 2020 and caused a global medical emergency. Healthcare professionals have been struggling to devise appropriate therapeutic strategies against the virus mainly due to the diverse range of symptoms and multiple-organ failure in infected patients. Several broad-spectrum antiviral drugs are being used for treatment; however, there is yet no specific drug or vaccine against the virus. Multiple-organ failure due to hyperactivity of the immune system resulting in cytokine storms is a major reason for death among the 5% critically ill patients. In this article, we have discussed the damage caused by COVID-19 on different organs of the human body.