Productive replication of Middle East respiratory syndrome coronavirus in monocyte-derived dendritic cells modulates innate immune response

Renal implications of coronavirus disease 2019: insights into viral tropism and clinical outcomes

In recent years, multiple coronaviruses have emerged, with the latest one, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing a global pandemic. Besides respiratory symptoms, some patients experienced extrapulmonary effects, such as cardiac damage or renal injury, indicating the broad tropism of SARS-CoV-2. The ability of the virus to effectively invade the renal cellular environment can eventually cause tissue-specific damage and disease. Indeed, patients with severe coronavirus disease 2019 exhibited a variety of symptoms such as acute proximal tubular injury, ischemic collapse, and severe acute tubular necrosis resulting in irreversible kidney failure. This review summarizes the current knowledge on how it is believed that SARS-CoV-2 influences the renal environment and induces kidney disease, as well as current therapy approaches.

Middle East respiratory coronavirus (MERS-CoV) internalized by llama alveolar macrophages does not result in virus replication or induction of pro-inflammatory cytokines

Severe Middle East respiratory syndrome (MERS) is characterized by massive infiltration of immune cells in lungs. MERS-coronavirus (MERS-CoV) replicates in vitro in human macrophages, inducing high pro-inflammatory responses. In contrast, camelids, the main reservoir for MERS-CoV, are asymptomatic carriers. Although limited infiltration of leukocytes has been observed in the lower respiratory tract of camelids, their role during infection remains unknown. Here we studied whether llama alveolar macrophages (LAMs) are susceptible to MERS-CoV infection and can elicit pro-inflammatory responses. MERS-CoV did not replicate in LAMs; however, they effectively capture and degrade viral particles. Moreover, transcriptomic analyses showed that LAMs do not induce pro-inflammatory cytokines upon MERS-CoV sensing.

The inflammatory spectrum of cardiomyopathies

Infiltration of the myocardium with various cell types, cytokines and chemokines plays a crucial role in the pathogenesis of cardiomyopathies including inflammatory cardiomyopathies and myocarditis. A more comprehensive understanding of the precise immune mechanisms involved in acute and chronic myocarditis is essential to develop novel therapeutic approaches. This review offers a comprehensive overview of the current knowledge of the immune landscape in cardiomyopathies based on etiology. It identifies gaps in our knowledge about cardiac inflammation and emphasizes the need for new translational approaches to improve our understanding thus enabling development of novel early detection methods and more effective treatments.

The role of DC-SIGN as a trans-receptor in infection by MERS-CoV

DC-SIGN is a C-type lectin expressed in myeloid cells such as immature dendritic cells and macrophages. Through glycan recognition in viral envelope glycoproteins, DC-SIGN has been shown to act as a receptor for a number of viral agents such as HIV, Ebola virus, SARS-CoV, and SARS-CoV-2. Using a system of Vesicular Stomatitis Virus pseudotyped with MERS-CoV spike protein, here, we show that DC-SIGN is partially responsible for MERS-CoV infection of dendritic cells and that DC-SIGN efficiently mediates trans-infection of MERS-CoV from dendritic cells to susceptible cells, indicating a potential role of DC-SIGN in MERS-CoV dissemination and pathogenesis.

Macrophage-Derived Chemokine MDC/CCL22: An Ambiguous Finding in COVID-19

Macrophage-derived chemokine (MDC/CCL22) is a chemokine of the C-C subfamily. It is involved in T-cellular maturation and migration. Our previous research shows that plasma CCL22/MDC tends to show a statistically significant depletion of concentrations in acute patients and convalescents when compared to healthy donors. In the current work, we investigate existing views on MDC/CCL22 dynamics in association with various pathologies, including respiratory diseases and, specifically, COVID-19. Additionally, we present our explanations for the observed decrease in MDC/CCL22 concentrations in COVID-19. The first hypothesis we provide implies that viral products bind to MDC/CCL22 and block its activity. Another explanation for this phenomenon is based on dendritic cells population and the inhibition of their function.

Drawing Parallels between SARS, MERS, and COVID-19: A Comparative Overview of Epidemiology, Pathogenesis, and Pathological Features

Background

Since November 2019, when the novel coronavirus arose in Wuhan City, over 188 million people worldwide have been infected with COVID-19. It is the third coronavirus outbreak in the twenty-first century. Until now, practically all coronavirus epidemics have occurred due to zoonotic spread from an animal or transitional host or through the consumption of their products. Coronaviruses can infect humans and cause severe illness and even death.

Material and Methods

This review was designed to help us recognize and harmonize the similarities and differences between these three coronaviridae family members.

Result

Measures aimed at containing the epidemic should be emphasized in this circumstance. Prioritizing and planning these activities require an understanding of the particulars of these three viruses. Given the pandemic's enormous death toll and rapid spread, we should be cognizant of the parallels and differences between these three viruses. Additionally, this pandemic warns us to be cautious against the possibility of a future pandemic.

Conclusion

We highlight the fundamental characteristics of coronaviruses that are critical for recognizing coronavirus epidemiology, pathogenesis, and pathological features that reveal numerous significant pathological attributes and evolutionary patterns in the viral genome that aid in better understanding and anticipating future epidemics.

The roles of critical pro-inflammatory cytokines in the drive of cytokine storm during SARS-CoV-2 infection

In patients with severe COVID-19, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), and even mortality can result from cytokine storm, which is a hyperinflammatory medical condition caused by the excessive and uncontrolled release of pro-inflammatory cytokines. High levels of numerous crucial pro-inflammatory cytokines, such as interleukin-1 (IL-1), IL-2, IL-6, tumor necrosis factor-α, interferon (IFN)-γ, IFN-induced protein 10 kDa, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein-1, and IL-10 and so on, have been found in severe COVID-19. They participate in cascade amplification pathways of pro-inflammatory responses through complex inflammatory networks. Here, we review the involvements of these critical inflammatory cytokines in SARS-CoV-2 infection and discuss their potential roles in triggering or regulating cytokine storm, which can help to understand the pathogenesis of severe COVID-19. So far, there is rarely effective therapeutic strategy for patients with cytokine storm besides using glucocorticoids, which is proved to result in fatal side effects. Clarifying the roles of key involved cytokines in the complex inflammatory network of cytokine storm will help to develop an ideal therapeutic intervention, such as neutralizing antibody of certain cytokine or inhibitor of some inflammatory signal pathways.

Engineering potent live attenuated coronavirus vaccines by targeted inactivation of the immune evasive viral deubiquitinase

Coronaviruses express a papain-like protease (PLpro) that is required for replicase polyprotein maturation and also serves as a deubiquitinating enzyme (DUB). In this study, using a Middle East respiratory syndrome virus (MERS-CoV) PLpro modified virus in which the DUB is selectively inactivated, we show that the PLpro DUB is an important MERS-CoV interferon antagonist and virulence factor. Although the DUB-negative rMERS-CoV_MA replicates robustly in the lungs of human dipeptidyl peptidase 4 knock-in (hDPP4 KI) mice, it does not cause clinical symptoms. Interestingly, a single intranasal vaccination with DUB-negative rMERS-CoV_MA induces strong and sustained neutralizing antibody responses and sterilizing immunity after a lethal wt virus challenge. The survival of naïve animals also significantly increases when sera from animals vaccinated with the DUB-negative rMERS-CoV_MA are passively transferred, prior to receiving a lethal virus dose. These data demonstrate that DUB-negative coronaviruses could be the basis of effective modified live attenuated vaccines.

Exploiting Signal Joint T Cell Receptor Excision Circle to Investigate the Impact of COVID-19 and Autoimmune Diseases on Age Prediction and Immunosenescence

Signal joint T cell receptor excision circles (sjTRECs) are a promising marker for age estimation and immunosenescence in different ethnic groups. Several limitations are expected to overshadow their use as accurate markers for age prediction. The current study was conducted to determine the influence of immunologic disorders, such as autoimmune diseases and COVID-19, on the accuracy of sjTRECs as molecular markers for age estimation and immunosenescence among living Egyptians. Peripheral blood sjTRECs level was measured by qPCR in 90 autoimmune patients, 58 COVID-19 patients, and 85 healthy controls. The mean dCt values were significantly (p = 0.0002) different between the three groups, with the highest values in healthy subjects, followed by autoimmune and COVID-19 patients. A significant negative correlation was identified between the sjTRECs levels and ages in all studied cases. There were significant positive correlations between chronological age and predicted age for healthy individuals, autoimmune, and COVID-19 patients with mean absolute deviations (MAD) of 9.40, 11.04, and 9.71, respectively. The two patients' groups exhibited early immunosenescence, which was more noticeable among the young adults with COVID-19 and autoimmune patients of age range (18-49 years). Autoimmunity may represent a critical factor impacting the accuracy of sjTRECs quantitation for age prediction.

Severe acute respiratory syndrome coronavirus 2 virus-like particles induce dendritic cell maturation and modulate T cell immunity

Dendritic cells (DCs) are professional antigen-presenting cells that play an important role in both innate and acquired immune responses against pathogens. However, the role of DCs in coronavirus disease 2019 (COVID-19) is unclear. Virus-like particles (VLPs) that structurally mimic the original virus are one of the candidates COVID-19 vaccines. In the present study, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) VLPs were used as an alternative to live virus to evaluate the interaction of the virus with DCs. The results revealed that SARS-CoV-2 VLPs induced DC maturation by augmenting cell surface molecule expression (CD80, CD86, and major histocompatibility complex class II (MHC-II)) and inflammatory cytokine production (tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-12p70) in DCs via the mitogen-activated protein kinase and nuclear factor-κB signaling pathways. In addition, mature DCs induced by SARS-CoV-2 VLPs promoted T cell proliferation, which was dependent on VLPs concentration. Our results suggest that SARS-CoV-2 VLPs regulate the immune response by interacting with DCs. These findings will improve the understanding of SARS-CoV-2 pathogenesis and SARS-CoV-2 vaccine development.

Comparative highlights on MERS-CoV, SARS-CoV-1, SARS-CoV-2, and NEO-CoV

The severe acute respiratory syndrome (SARS-CoV, now SARS-CoV-1), middle east respiratory syndrome (MERS-CoV), Neo-CoV, and 2019 novel coronavirus (SARS-CoV-2/COVID-19) are the most notable coronaviruses, infecting the number of people worldwide by targeting the respiratory system. All these viruses are of zoonotic origin, predominantly from bats which are one of the natural reservoir hosts for coronaviruses. Thus, the major goal of our review article is to compare and contrast the characteristics and attributes of these coronaviruses. The SARS-CoV-1, MERS-CoV, and COVID-19 have many viral similarities due to their classification, they are not genetically related. COVID-19 shares approximately 79 % of its genome with SARS-CoV-1 and about 50 % with MERS-CoV. The shared receptor protein, ACE2 exhibit the most striking genetic similarities between SARS-CoV-1 and SARS-CoV-2. SARS-CoV primarily replicates in the epithelial cells of the respiratory system, but it may also affect macrophages, monocytes, activated T cells, and dendritic cells. MERS-CoV not only infects and replicates inside the epithelial and immune cells, but it may lyse them too, which is one of the common reasons for MERS's higher mortality rate. The details of infections caused by SARS-CoV-2 and lytic replication mechanisms in host cells are currently mysterious. In this review article, we will discuss the comparative highlights of SARS-CoV-1, MERS-CoV, SARS-CoV-2, and Neo-CoV, concerning their structural features, morphological characteristics, sources of virus origin and their evolutionary transitions, infection mechanism, computational study approaches, pathogenesis and their severity towards several diseases, possible therapeutic approaches, and preventive measures.

Non‐productive exposure of PBMCs to SARS‐CoV ‐2 induces cell‐intrinsic innate immune responses

Cell‐intrinsic responses mounted in PBMCs during mild and severe COVID‐19 differ quantitatively and qualitatively. Whether they are triggered by signals emitted by productively infected cells of the respiratory tract or result from physical interaction with virus particles remains unclear. Here, we analyzed susceptibility and expression profiles of PBMCs from healthy donors upon ex vivo exposure to SARS‐CoV and SARS‐CoV‐2. In line with the absence of detectable ACE2 receptor expression, human PBMCs were refractory to productive infection. RT–PCR experiments and single‐cell RNA sequencing revealed JAK/STAT‐dependent induction of interferon‐stimulated genes (ISGs) but not proinflammatory cytokines. This SARS‐CoV‐2‐specific response was most pronounced in monocytes. SARS‐CoV‐2‐RNA‐positive monocytes displayed a lower ISG signature as compared to bystander cells of the identical culture. This suggests a preferential invasion of cells with a low ISG baseline profile or delivery of a SARS‐CoV‐2‐specific sensing antagonist upon efficient particle internalization. Together, nonproductive physical interaction of PBMCs with SARS‐CoV‐2‐ and, to a much lesser extent, SARS‐CoV particles stimulate JAK/STAT‐dependent, monocyte‐accentuated innate immune responses that resemble those detected in vivo in patients with mild COVID‐19.

Targeting ACLY efficiently inhibits SARS-CoV-2 replication

The Coronavirus Disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the biggest public health challenge the world has witnessed in the past decades. SARS-CoV-2 undergoes constant mutations and new variants of concerns (VOCs) with altered transmissibility, virulence, and/or susceptibility to vaccines and therapeutics continue to emerge. Detailed analysis of host factors involved in virus replication may help to identify novel treatment targets. In this study, we dissected the metabolome derived from COVID-19 patients to identify key host factors that are required for efficient SARS-CoV-2 replication. Through a series of metabolomic analyses, in vitro, and in vivo investigations, we identified ATP citrate lyase (ACLY) as a novel host factor required for efficient replication of SARS-CoV-2 wild-type and variants, including Omicron. ACLY should be further explored as a novel intervention target for COVID-19.

Comparative overview of emerging RNA viruses: Epidemiology, pathogenesis, diagnosis and current treatment

From many decades, emerging infections have threatened humanity. The pandemics caused by different CoVs have already claimed and will continue to claim millions of lives. The SARS, Ebola, MERS epidemics and the most recent emergence of COVID-19 pandemic have threatened populations across borders. Since a highly pathogenic CoV has been evolved into the human population in the twenty-first century known as SARS, scientific advancements and innovative methods to tackle these viruses have increased in order to improve response preparedness towards the unpredictable threat posed by these rapidly emerging pathogens. Recently published review articles on SARS-CoV-2 have mainly focused on its pathogenesis, epidemiology and available treatments. However, in this review, we have done a systematic comparison of all three CoVs i.e., SARS, MERS and SARS-CoV-2 along with Ebola and Zika in terms of their epidemiology, virology, clinical features and current treatment strategies. This review focuses on important emerging RNA viruses starting from Zika, Ebola and the CoVs which include SARS, MERS and SARS-CoV-2. Each of these viruses has been elaborated on the basis of their epidemiology, virulence, transmission and treatment. However, special attention has been given to SARS-CoV-2 and the disease caused by it i.e., COVID-19 due to current havoc caused worldwide. At the end, insights into the current understanding of the lessons learned from previous epidemics to combat emerging CoVs have been described. The travel-related viral spread, the unprecedented nosocomial outbreaks and the high case-fatality rates associated with these highly transmissible and pathogenic viruses highlight the need for new prophylactic and therapeutic actions which include but are not limited to clinical indicators, contact tracing, and laboratory investigations as important factors that need to be taken into account in order to arrive at the final conclusion.

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Recently published review articles on SARS-CoV-2 have mainly focused on its pathogenesis, epidemiology and available treatments.

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The pandemics caused by different CoVs have already claimed and will continue to claim millions of lives.

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This review focuses on important emerging RNA viruses starting from Zika, Ebola and the CoVs which include SARS, MERS and SARS-CoV-2.

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Globally, numerous studies and researchers have recently started fighting this virus.

Dendritic cell vaccine as a potential strategy to end the COVID-19 pandemic. Why should it be Ex Vivo?

INTRODUCTION

Developing a safe and efficacious vaccine that can induce broad and long-term immunity for SARS-CoV-2 infection is the most critical research to date. As the most potent APCs, dendritic cells (DCs) can induce a robust T cell immunity. In addition, DCs also play an essential role in COVID-19 pathogenesis, making them a potential vaccination target. However, the DCs-based vaccine with ex vivo loading has not yet been explored for COVID-19.

AREAS COVERED

This review aims to provide the rationale for developing a DCs-based vaccine with ex vivo loading of SARS-CoV-2 antigen. Here, we discuss the role of DCs in immunity and the effect of SARS-CoV-2 infection on DCs. Then, we propose the mechanism of the DCs-based vaccine in inducing immunity and highlight the benefits of ex vivo loading of antigen.

EXPERT OPINION

We make the case that an ex vivo loaded DC-based vaccination is appropriate for COVID-19 prevention.

The role of antigen-presenting cells in the pathogenesis of COVID-19

Coronavirus Disease 2019 (COVID-19) is one of the three lethal coronavirus outbreaks in the recent two decades and a serious threat to global health all over the world. The principal feature of the COVID-19 infection is the so-called "cytokine storm" exaggerated molecular response to virus distribution, which plays massive tissue and organ injury roles. Immunological treatments, including monoclonal antibodies and vaccines, have been suggested as the main approaches in treating and preventing this disease. Therefore, a proper investigation of the roles of antigen-presenting cells (APCs) in the aforementioned immunological responses appears essential. The present review will provide detailed information about APCs' role in the infection and pathogenesis of SARS-CoV-2 and the effect of monoclonal antibodies in diagnosis and treatment.

The Role of Cytokines and Chemokines in Severe Acute Respiratory Syndrome Coronavirus 2 Infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in countless infections and caused millions of deaths since its emergence in 2019. Coronavirus disease 2019 (COVID-19)-associated mortality is caused by uncontrolled inflammation, aberrant immune response, cytokine storm, and an imbalanced hyperactive immune system. The cytokine storm further results in multiple organ failure and lung immunopathology. Therefore, any potential treatments should focus on the direct elimination of viral particles, prevention strategies, and mitigation of the imbalanced (hyperactive) immune system. This review focuses on cytokine secretions of innate and adaptive immune responses against COVID-19, including interleukins, interferons, tumor necrosis factor-alpha, and other chemokines. In addition to the review focus, we discuss potential immunotherapeutic approaches based on relevant pathophysiological features, the systemic immune response against SARS-CoV-2, and data from recent clinical trials and experiments on the COVID-19-associated cytokine storm. Prompt use of these cytokines as diagnostic markers and aggressive prevention and management of the cytokine storm can help determine COVID-19-associated morbidity and mortality. The prophylaxis and rapid management of the cytokine storm appear to significantly improve disease outcomes. For these reasons, this study aims to provide advanced information to facilitate innovative strategies to survive in the COVID-19 pandemic.

Depletion and Dysfunction of Dendritic Cells: Understanding SARS-CoV-2 Infection

Uncontrolled severe acute respiratory syndrome-coronavirus (SARS-CoV)-2 infection is closely related to disorders of the innate immune and delayed adaptive immune systems. Dendritic cells (DCs) “bridge” innate immunity and adaptive immunity. DCs have important roles in defending against SARS-CoV-2 infection. In this review, we summarize the latest research concerning the role of DCs in SARS-CoV-2 infection. We focus on the complex interplay between DCs and SARS-CoV-2: pyroptosis-induced activation; activation of the renin–angiotensin–aldosterone system; and activation of dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin. We also discuss the decline in DC number, the impaired antigen-presentation capability, and the reduced production of type-I interferon of DCs in severe SARS-CoV-2 infection. In addition, we discuss the potential mechanisms for pathological activation of DCs to understand the pattern of SARS-CoV-2 infection. Lastly, we provide a brief overview of novel vaccination and immunotherapy strategies based on DC targeting to overcome SARS-CoV-2 infection.

Severe versus common COVID-19: an early warning nomogram model

The wide spread of coronavirus disease 2019 is currently the most rigorous health threat, and the clinical outcomes of severe patients are extremely poor. In this study, we establish an early warning nomogram model related to severe versus common COVID-19. A total of 1059 COVID-19 patients were analyzed in the primary cohort and divided into common and severe according to the guidelines on the Diagnosis and Treatment of COVID-19 by the National Health Commission of China (7th version). The clinical data were collected for logistic regression analysis to assess the risk factors for severe versus common type. Furthermore, 123 COVID-19 patients were reviewed as the validation cohort to assess the performance of this model. Multivariate logistic analysis revealed that age, dyspnea, lymphocyte count, C-reactive protein and interleukin-6 were independent factors for prewarning the severe type occurrence. Then, the early warning nomogram model including these risk factors for inferring the severe disease occurrence out of common type of COVID-19 was constructed. The C-index of this nomogram in the primary cohort was 0.863, 95% confidence interval (CI) (0.836-0.889). Meanwhile, in the validation cohort, the C-index of this nomogram was 0.889, 95% CI (0.828-0.950). In both the primary cohort and validation cohorts, the calibration curve showed good agreement between prediction and actual probability. The early warning model shows that data at the very beginning including age, dyspnea, lymphocyte count, CRP, and IL-6 may prewarn the severe disease occurrence to some extent, which could help clinicians early and timely treatment.

Immune Profiling of COVID-19 in Correlation with SARS and MERS

Acute respiratory distress syndrome (ARDS) is a major complication of the respiratory illness coronavirus disease 2019, with a death rate reaching up to 40%. The main underlying cause of ARDS is a cytokine storm that results in a dysregulated immune response. This review discusses the role of cytokines and chemokines in SARS-CoV-2 and its predecessors SARS-CoV and MERS-CoV, with particular emphasis on the elevated levels of inflammatory mediators that are shown to be correlated with disease severity. For this purpose, we reviewed and analyzed clinical studies, research articles, and reviews published on PubMed, EMBASE, and Web of Science. This review illustrates the role of the innate and adaptive immune responses in SARS, MERS, and COVID-19 and identifies the general cytokine and chemokine profile in each of the three infections, focusing on the most prominent inflammatory mediators primarily responsible for the COVID-19 pathogenesis. The current treatment protocols or medications in clinical trials were reviewed while focusing on those targeting cytokines and chemokines. Altogether, the identified cytokines and chemokines profiles in SARS-CoV, MERS-CoV, and SARS-CoV-2 provide important information to better understand SARS-CoV-2 pathogenesis and highlight the importance of using prominent inflammatory mediators as markers for disease diagnosis and management. Our findings recommend that the use of immunosuppression cocktails provided to patients should be closely monitored and continuously assessed to maintain the desirable effects of cytokines and chemokines needed to fight the SARS, MERS, and COVID-19. The current gap in evidence is the lack of large clinical trials to determine the optimal and effective dosage and timing for a therapeutic regimen.

Immune responses in SARS-CoV-2, SARS-CoV, and MERS-CoV infections: A comparative review

Coronavirus, discovered in the 1960s, is able to infect human hosts and causes mild to serious respiratory problems. In the last two decades, the severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been recognized. It has long been demonstrated that MERS-CoV binds to dipeptidyl peptidase 4 and SARS-CoV binds to angiotensin-converting enzyme 2. A “cytokine storm” is the main pathophysiology of aforementioned viruses. Infiltration of neutrophils at the site of the infection is a risk factor for the development of acute respiratory distress syndrome and death. The new coronavirus, SARS-CoV-2, has infected more people than SARS-Cov and MERS-CoV as it can easily be transmitted from person to person. Epidemiological studies indicate that majority of individuals are asymptomatic; therefore, an effective and an efficient tool is required for rapid testing. Identification of various cytokine and inflammatory factor expression levels can help in outcome prediction. In this study we reviewed immune responses in SARS-CoV, Mers-CoV, and SARS-COV-2 infections and the role of inflammatory cells.

High Levels of Circulating IL-6 and IL-8 Signature can Predict COVID-19 Severity

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may trigger a cytokine storm, which is characterized by uncontrolled overproduction of proinflammatory cytokines. Objectives: We aimed to investigate the association between circulating levels of inflammatory cytokines and severity of coronavirus disease 2019 (COVID-19). Methods: This cross-sectional study included 46 severe and 32 mildly symptomatic COVID-19 patients. The serum levels of cytokines and chemokines were determined using the Bio-Plex ProTM Human Cytokine Screening Panel. Results: Out of a total of 78 patients with confirmed COVID-19, 54 (69.2%) were males, and 24 (30.8%) were females. The mean age was 43.1 ± 13.3 and 58.2 ± 15 in mild and severe patients, respectively. Severe patients were characterized by significant laboratory abnormalities, such as increased WBC (P = 0.002) and neutrophil counts (P = 0.001), higher levels of ALT (P = 0.03), AST (P = 0.002), LDH (P < 0.001), urea (P = 0.013), ferritin (P < 0.001), D-dimer (P = 0.042), CRP (P < 0.001), and decreased lymphocyte (P < 0.001) and platelet (P = 0.045) counts. The levels of IL-6, IL-8, IL-13, TNF-α, IFN-γ, MIP-1β, and MCP-1 increased in the severe group compared to the mild group. However, significant differences were observed only for IL-6 (P < 0.001) and IL-8 (P < 0.001) levels. Conclusions: Serum IL-6 and IL-8 levels can be used as potential prognostic biomarkers of disease severity in COVID-19 patients.

Innate Immunity Evasion Strategies of Highly Pathogenic Coronaviruses: SARS-CoV, MERS-CoV, and SARS-CoV-2

In the past two decades, coronavirus (CoV) has emerged frequently in the population. Three CoVs (SARS-CoV, MERS-CoV, SARS-CoV-2) have been identified as highly pathogenic human coronaviruses (HP-hCoVs). Particularly, the ongoing COVID-19 pandemic caused by SARS-CoV-2 warns that HP-hCoVs present a high risk to human health. Like other viruses, HP-hCoVs interact with their host cells in sophisticated manners for infection and pathogenesis. Here, we reviewed the current knowledge about the interference of HP-hCoVs in multiple cellular processes and their impacts on viral infection. HP-hCoVs employed various strategies to suppress and evade from immune response, including shielding viral RNA from recognition by pattern recognition receptors (PRRs), impairing IFN-I production, blocking the downstream pathways of IFN-I, and other evasion strategies. This summary provides a comprehensive view of the interplay between HP-hCoVs and the host cells, which is helpful to understand the mechanism of viral pathogenesis and develop antiviral therapies.

Crosstalk between estrogen, dendritic cells, and SARS-CoV-2 infection

The novel coronavirus disease 2019 (Covid‐19) first appeared in Wuhan and has so far killed more than four million people worldwide. Men are more affected than women by Covid‐19, but the cellular and molecular mechanisms behind these differences are largely unknown. One plausible explanation is that differences in sex hormones could partially account for this distinct prevalence in both sexes. Accordingly, several papers have reported a protective role of 17β‐estradiol during Covid‐19, which might help explain why women appear less likely to die from Covid‐19 than men. 17β‐estradiol is the predominant and most biologically active endogenous estrogen, which signals through estrogen receptor α, estrogen receptor β, and G protein‐coupled estrogen receptor 1. These receptors are expressed in mature cells from the innate and the adaptive immune system, particularly on dendritic cells (DCs), suggesting that estrogens could modulate their effector functions. DCs are the most specialized and proficient antigen‐presenting cells, acting at the interface of innate and adaptive immunity with a powerful capacity to prime antigen‐specific naive CD8+ T cells. DCs are richly abundant in the lung where they respond to viral infection. A relative increase of mature DCs in broncho‐alveolar lavage fluids from Covid‐19 patients has already been reported. Here we will describe how SARS‐CoV‐2 acts on DCs, the role of estrogen on DC immunobiology, summarise the impact of sex hormones on the immune response against Covid‐19, and explore clinical trials regarding Covid‐19

Proteomics and lipidomics reveal the protective mechanism of dietary n-3 PUFA supplementation for photoaging

Chronic ultraviolet radiation exposure could induce photoaging, and even carcinogenesis. Dietary omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation has proved to alleviate photoaging and cutaneous carcinoma. Although the exact mechanism remains poorly elucidated, accumulated evidence suggests that the alleviation effect of n-3 PUFA for photoaging is a multifactorial procession characterized by different pathways. Here, we performed a whole-genome proteomics and lipidomics analyses using a self-constructed photoaging mouse model with n-3 PUFA or n-6 PUFA supplementation. Significant alleviation of photoaging was observed, and a total of 88 differentially expressed proteins and 152 differentially expressed lipids were identified in mice with n-3 PUFA supplementation. We found that n-3 PUFA may alleviate photoaging by upregulating Hmmr (hyaluronic acid receptor) expression, which can decrease Mmp9 expression, reducing collagen degradation. As most proteins were associated with lipogenesis and lipid metabolism, we further analyzed the lipidomics data, finding that most triglycerides (93%) showed a significant increase in the n-3 PUFA supplementation group. Our proteomics and lipidomics results indicate that the protective mechanism of n-3 PUFA for photoaging is complicated. Furthermore, the effect of elevated triglycerides by n-3 PUFA supplementation in counteracting skin photoaging cannot be ignored, which will become a new prime target in anti-photoaging.

An overview on the seven pathogenic human coronaviruses

To date, seven human coronaviruses (HCoVs) have been detected: HCoV-NL63, HCoV-229E, HCoV-HKU1, HCoV-OC43, severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2. Four of these viruses, including HCoV-NL63, -229E, -HKU1 and -OC43, usually cause mild-to-moderate respiratory diseases with a seasonal pattern. Since 2000, three new HCoVs have emerged with a significant mortality rate. Although SARS-CoV and MERS-CoV caused an epidemic in some countries, SARS-CoV-2 escalated into a pandemic. All HCoVs can cause severe complications in the elderly and immunocompromised individuals. The bat origin of HCoVs, the presence of intermediate hosts and the nature of their viral replication suggest that other new coronaviruses may emerge in the future. Despite the fact that all HCoVs share similarities in viral replication, they differ in their accessory proteins, incubation period and pathogenicity. This study aims to review these differences between the seven HCoVs.

The lethal internal face of the coronaviruses: Kidney tropism of the SARS, MERS, and COVID19 viruses

The kidney is one of the main targets attacked by viruses in patients with a coronavirus infection. Until now, SARS-CoV-2 has been identified as the seventh member of the coronavirus family capable of infecting humans. In the past two decades, humankind has experienced outbreaks triggered by two other extremely infective members of the coronavirus family; the MERS-CoV and the SARS-CoV. According to several investigations, SARS-CoV causes proteinuria and renal impairment or failure. The SARS-CoV was identified in the distal convoluted tubules of the kidney of infected patients. Also, renal dysfunction was observed in numerous cases of MERS-CoV infection. And recently, during the 2019-nCoV pandemic, it was found that the novel coronavirus not only induces acute respiratory distress syndrome (ARDS) but also can induce damages in various organs including the liver, heart, and kidney. The kidney tissue and its cells are targeted massively by the coronaviruses due to the abundant presence of ACE2 and Dpp4 receptors on kidney cells. These receptors are characterized as the main route of coronavirus entry to the victim cells. Renal failure due to massive viral invasion can lead to undesirable complications and enhanced mortality rate, thus more attention should be paid to the pathology of coronaviruses in the kidney. Here, we have provided the most recent knowledge on the coronaviruses (SARS, MERS, and COVID19) pathology and the mechanisms of their impact on the kidney tissue and functions.

Human Coronaviruses: Counteracting the Damage by Storm

Over the past 18 years, three highly pathogenic human (h) coronaviruses (CoVs) have caused severe outbreaks, the most recent causative agent, SARS-CoV-2, being the first to cause a pandemic. Although much progress has been made since the COVID-19 pandemic started, much about SARS-CoV-2 and its disease, COVID-19, is still poorly understood. The highly pathogenic hCoVs differ in some respects, but also share some similarities in clinical presentation, the risk factors associated with severe disease, and the characteristic immunopathology associated with the progression to severe disease. This review aims to highlight these overlapping aspects of the highly pathogenic hCoVs-SARS-CoV, MERS-CoV, and SARS-CoV-2-briefly discussing the importance of an appropriately regulated immune response; how the immune response to these highly pathogenic hCoVs might be dysregulated through interferon (IFN) inhibition, antibody-dependent enhancement (ADE), and long non-coding RNA (lncRNA); and how these could link to the ensuing cytokine storm. The treatment approaches to highly pathogenic hCoV infections are discussed and it is suggested that a greater focus be placed on T-cell vaccines that elicit a cell-mediated immune response, using rapamycin as a potential agent to improve vaccine responses in the elderly and obese, and the potential of stapled peptides as antiviral agents.

Two novel nomograms based on inflammatory cytokines or lymphocyte subsets to differentially diagnose severe or critical and Non-Severe COVID-19

We intend to evaluate the differences of the clinical characteristics, cytokine profiles and immunological features in patients with different severity of COVID-19, and to develop novel nomograms based on inflammatory cytokines or lymphocyte subsets for the differential diagnostics for severe or critical and non-severe COVID-19 patients. We retrospectively studied 254 COVID-19 patients, 90 of whom were severe or critical patients and 164 were non-severe patients. Severe or critical patients had significantly higher levels of inflammatory cytokines than non-severe patients as well as lower levels of lymphocyte subsets. Significantly positive correlations between cytokine profiles were observed, while they were all significantly negatively correlated with lymphocyte subsets. Two effective nomograms were developed according to two multivariable logistic regression cox models based on inflammatory cytokine profiles and lymphocyte subsets separately. The areas under the receiver operating characteristics of two nomograms were 0.834 (95% CI: 0.779-0.888) and 0.841 (95% CI: 0.756-0.925). The bootstrapped-concordance indexes of two nomograms were 0.834 and 0.841 in training set, and 0.860 and 0.852 in validation set. Calibration curves and decision curve analyses demonstrated that the nomograms were well calibrated and had significantly more clinical net benefits. Our novel nomograms can accurately predict disease severity of COVID-19, which may facilitate the identification of severe or critical patients and assist physicians in making optimized treatment suggestions.

Immune Intervention in Sepsis

Sepsis is a host immune disorder induced by infection. It can lead to multiple organ dysfunction syndrome (MODS), which has high morbidity and mortality. There has been great progress in the clinical diagnosis and treatment of sepsis, such as improvements in pathogen detection technology, innovations regarding anti-infection drugs, and the development of organ function support. Abnormal immune responses triggered by pathogens, ranging from excessive inflammation to immunosuppression, are recognized to be an important cause of the high mortality rate. However, no drugs have been approved specifically for treating sepsis. Here, we review the recent research progress on immune responses in sepsis to provide a theoretical basis for the treatment of sepsis. Constructing and optimizing a dynamic immune system treatment regimen based on anti-infection treatment, fluid replacement, organ function support, and timely use of immunomodulatory interventions may improve the prognosis of sepsis patients.

Consequences of coronavirus infections for primitive and mature hematopoietic cells: new insights and why it matters

PURPOSE OF REVIEW

In recent history there have been three outbreaks of betacoronavirus infections in humans, with the most recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; causing Coronavirus disease 2019 [COVID-19]) outbreak leading to over two million deaths, with a rapidly rising death toll. Much remains unknown about host cells and tissues affected by coronavirus infections, including the hematopoietic system. Here, we discuss the recent findings examining effects that coronavirus infection or exposure has on hematopoietic cells and the clinical implications for these effects.

RECENT FINDINGS

Recent studies have centered on SARS-CoV-2, demonstrating that hematopoietic stem and progenitor cells and mature immune cells may be susceptible to infection and are impacted functionally by exposure to SARS-CoV-2 Spike protein. These findings have important implications regarding hematologic complications arising from COVID-19 and other coronavirus-induced disease, which we discuss here.

SUMMARY

Infection with coronaviruses sometimes leads to hematologic complications in patients, and these hematologic complications are associated with poorer prognosis. These hematologic complications may be caused by coronavirus direct infection or impact on primitive hematopoietic cells or mature immune cells, by indirect effects on these cells, or by a combination thereof. It is important to understand how hematologic complications arise in order to seek new treatments to improve patient outcomes.

SARS-CoV-2 Genetic Variability and Non-Specific Immunity Associated with the Use of Different BCG Strains-A Molecular and Clinical Approach

The effect of BCG vaccination against tuberculosis on the reduction in COVID-19 infection is related to the effect of the BCG vaccine on the immunomodulation of non-specific immunity. In the early stages of the pandemic, countries with universal BCG vaccination programs registered a low number of new cases of COVID-19, with the situation now reversed, as exemplified by India. The high genetic variability of SARS-CoV-2, a known characteristic of RNA viruses, causing the occurrence of SARS-CoV-2 variants may have led to the virus adapting to overcome the initial immune protection. The strains from the United Kingdom (B1.1.7), Brazil (B1.1.28 and B1.1.33), South Africa (B.1.351), and India (B.1.617) are characterized by a greater ability to spread in the environment, in comparison with the original infectious agent of SARS-CoV-2. It should be remembered that the large variation in the genetic makeup of SARS-CoV-2 may result in future changes in its pathogenicity, immunogenicity and antigenicity, and therefore it is necessary to carefully study the mutations occurring within the virus to determine whether the current vaccines will remain effective. However, most studies show that monoclonal antibodies produced after vaccination against COVID-19 are effective against the newly developed variants.

STAT2-dependent restriction of Zika virus by human macrophages but not dendritic cells

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus that poses significant threats to global public health. Macrophages and dendritic cells are both key sentinel cells in the host immune response and play critical roles in the pathogenesis of flavivirus infections. Recent studies showed that ZIKV could productively infect monocyte-derived dendritic cells (moDCs), but the role of macrophages in ZIKV infection remains incompletely understood. In this study, we first compared ZIKV infection in monocyte-derived macrophages (MDMs) and moDCs derived from the same donors. We demonstrated that while both MDMs and moDCs were susceptible to epidemic (Puerto Rico) and pre-epidemic (Uganda) strains of ZIKV, virus replication was largely restricted in MDMs but not in moDCs. ZIKV induced significant apoptosis in moDCs but not MDMs. The restricted virus replication in MDMs was not due to inefficient virus entry but was related to post-entry events in the viral replication cycle. In stark contrast with moDCs, ZIKV failed to inhibit STAT1 and STAT2 phosphorylation in MDMs. This resulted in the lack of efficient antagonism of the host type I interferon-mediated antiviral responses. Importantly, depletion of STAT2 but not STAT1 in MDMs significantly rescued the replication of ZIKV and the prototype flavivirus yellow fever virus. Overall, our findings revealed a differential interplay between macrophages and dendritic cells with ZIKV. While dendritic cells may be exploited by ZIKV to facilitate virus replication, macrophages restricted ZIKV infection.

Middle East Respiratory Syndrome (MERS) Virus-Pathophysiological Axis and the Current Treatment Strategies

Middle East respiratory syndrome (MERS) is a lethal respiratory disease with its first case reported back in 2012 (Jeddah, Saudi Arabia). It is a novel, single-stranded, positive-sense RNA beta coronavirus (MERS-CoV) that was isolated from a patient who died from a severe respiratory illness. Later, it was found that this patient was infected with MERS. MERS is endemic to countries in the Middle East regions, such as Saudi Arabia, Jordan, Qatar, Oman, Kuwait and the United Arab Emirates. It has been reported that the MERS virus originated from bats and dromedary camels, the natural hosts of MERS-CoV. The transmission of the virus to humans has been thought to be either direct or indirect. Few camel-to-human transmissions were reported earlier. However, the mode of transmission of how the virus affects humans remains unanswered. Moreover, outbreaks in either family-based or hospital-based settings were observed with high mortality rates, especially in individuals who did not receive proper management or those with underlying comorbidities, such as diabetes and renal failure. Since then, there have been numerous reports hypothesising complications in fatal cases of MERS. Over the years, various diagnostic methods, treatment strategies and preventive measures have been strategised in containing the MERS infection. Evidence from multiple sources implicated that no treatment options and vaccines have been developed in specific, for the direct management of MERS-CoV infection. Nevertheless, there are supportive measures outlined in response to symptom-related management. Health authorities should stress more on infection and prevention control measures, to ensure that MERS remains as a low-level threat to public health.

Clinical characteristics and outcomes of patients with COVID-19 pneumonia admitted to an intensive care unit in Faisalabad, Pakistan

AIM

To describe the clinical characteristics and outcomes of adult patients with severe COVID-19, with the exploration of risk factors for mortality in the hospital.

METHODS

This study included 20 adult patients diagnosed with COVID-19 admitted to the ICU of DHQ Hospital, Faisalabad (Pakistan). Patients were categorised into the survival group and the death group according to the outcome. We retrieved demographics, clinical manifestations and signs, laboratory indicators, treatment measures and clinical outcomes from the medical record, and summarised the clinical characteristics and outcomes of these patients.

RESULTS

The average age of patients was 70 ± 12 years, of which 40% were male. They were admitted to the ICU 11 days after the onset of symptoms. The most common symptoms on admission were cough (19 cases, 95%), fatigue or myalgia (18 cases, 90%), fever (17 cases, 85%) and dyspnoea (16 cases, 80%). Eleven (55%) patients had underlying diseases, of which hypertension was the most common (11 cases, 55%), followed by cardiovascular disease (4 cases, 20%) and diabetes (3 cases, 15%). Six patients (30%) received invasive mechanical ventilation and continuous renal replacement therapy and eventually died. Acute heart injury was the most common complication (19 cases, 95%). Ten (50%) patients died between 2 and 19 days after admission to the ICU. Compared with dead patients, the average body weight of surviving patients was lower (61.70 ± 2.36 vs 68.60 ± 7.15, P = .01), Glasgow Coma Scale score was higher (14.69 ± 0.70 vs 12.70 ± 2.45, P = .03), with fewer concurrent shocks (2 vs 10, P = .001) and acute respiratory distress syndrome (2 vs 10, P = .001).

CONCLUSION

The mortality rate is high in critically ill patients with COVID-19. Lower Glasgow Coma Scale, higher body weight and decreased lymphocyte count appear to be potential risk factors for the death of patients with COVID-19 in the ICU.

The COVID-19 puzzle: deciphering pathophysiology and phenotypes of a new disease entity

The zoonotic SARS-CoV-2 virus that causes COVID-19 continues to spread worldwide, with devastating consequences. While the medical community has gained insight into the epidemiology of COVID-19, important questions remain about the clinical complexities and underlying mechanisms of disease phenotypes. Severe COVID-19 most commonly involves respiratory manifestations, although other systems are also affected, and acute disease is often followed by protracted complications. Such complex manifestations suggest that SARS-CoV-2 dysregulates the host response, triggering wide-ranging immuno-inflammatory, thrombotic, and parenchymal derangements. We review the intricacies of COVID-19 pathophysiology, its various phenotypes, and the anti-SARS-CoV-2 host response at the humoral and cellular levels. Some similarities exist between COVID-19 and respiratory failure of other origins, but evidence for many distinctive mechanistic features indicates that COVID-19 constitutes a new disease entity, with emerging data suggesting involvement of an endotheliopathy-centred pathophysiology. Further research, combining basic and clinical studies, is needed to advance understanding of pathophysiological mechanisms and to characterise immuno-inflammatory derangements across the range of phenotypes to enable optimum care for patients with COVID-19.

The Immune Responses against Coronavirus Infections: Friend or Foe?

Coronaviruses (CoVs) were first discovered in the 1960s. Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) has been identified as the cause of COVID-19, which spread throughout China and subsequently, across the world. As COVID-19 causes serious public health concerns across the world, investigating the characteristics of SARS-CoV-2 and its interaction with the host immune responses may provide a clearer picture of how the pathogen causes disease in some individuals. Interestingly, SARS-CoV-2 has 80% sequence homology with SARS-CoV-1 and 96-98% homology with CoVs isolated from bats. Therefore, the experience acquired in SARS and Middle East Respiratory Syndrome (MERS) epidemics may improve our understanding of the immune response and immunopathological changes in COVID-19 patients. In the present paper, we have reviewed the immune responses (including the innate and adaptive immunities) to SARS-CoV, MERS-CoV, and SARS-CoV-2, so as to improve our understanding of the concept of the COVID-19 disease, which will be helpful in developing vaccines and medications for treating the COVID-19 patients.

Immunological and inflammatory profiles during acute and convalescent phases of severe/ critically ill COVID-19 patients

Background

The 2019 Coronavirus (COVID-19) pandemic poses a huge threat internationally; however, the role of the host immune system in the pathogenesis of COVID-19 is not well understood.

Methods

Cytokine and chemokine levels and characterisation of immune cell subsets from 20 COVID-19 cases after hospital admission (17 critically ill and 3 severe patients) and 16 convalescent patients were determined using a multiplex immunoassay and flow cytometry, respectively.

Results

IP-10, MCP-1, MIG, IL-6, and IL-10 levels were significantly higher in acute severe/critically ill patients with COVID-19, whereas were normal in patients who had reached convalescence. CD8 T cells in severe and critically ill COVID-19 patients expressed high levels of cytotoxic granules (granzyme B and perforin)and was hyperactivated as evidenced by the high proportions of CD38. Furthermore, the cytotoxic potential of natural killer (NK) cells, and the frequencies of myeloid dendritic cells and plasmacytoid dendritic cells was reduced in patients with severe and critical COVID-19; however, these dysregulations were found to be restored in convalescent phases.

Conclusion

Thus, elicitation of the hyperactive cytokine-mediated inflammatory response, dysregulation of CD8 T and NK cells, and deficiency of host myeloid and plasmacytoid DCs, may contribute to COVID-19 pathogenesis and provide insights into potential therapeutic targets and strategies.

SARS-Cov-2 and COVID-19, Basic and Clinical Aspects of the Human Pandemic: A Review

In the last two decades, we have witnessed three major epidemics of the coronavirus human disease namely, severe acute respiratory syndrome (SARS), Middle Eastern respiratory syndrome, and more recently an ongoing global pandemic of coronavirus disease 2019 (COVID-19). Iran, a country of nearly 84 million, in the Middle East, severely involved with the COVID-19 disease. A documented multidimensional approach to COVID-19 disease is therefore mandatory to provide a well-balanced platform for the concerned medical community in our county and beyond. In this review, we highlight the disease status in Iran and attempt to provide a multilateral view of the fundamental and clinical aspects of the disease including the clinical features of the confirmed cases, virology, pathogenesis, epidemiology, and laboratory methods needed for diagnosis.

Coronaviruses in humans and animals: the role of bats in viral evolution

Bats act as a natural reservoir for many viruses, including coronaviruses, and have played a crucial epidemiological role in the emergence of many viral diseases. Coronaviruses have been known for 60 years. They are usually responsible for the induction of mild respiratory signs in humans. However, since 2002, the bat-borne virus started to induce fatal epidemics according to WHO reports. In this year, the first serious human coronavirus epidemic (severe acute respiratory syndrome; SARS) occurred (China, 8098 cases, 774 deaths [9.5% of the cases] in 17 countries). The case fatality was higher in elderly patients above 60 years and reached 50% of the cases. SARS epidemic was followed 10 years later by the emergence of the middle east respiratory syndrome (MERS) in Saudi Arabia (in 2012, 2260 cases, 803 deaths [35.5% of the cases] in 27 countries). Finally, in December 2019, a new epidemic in Wuhan, China, (corona virus disease 2019, COVID-19) emerged and could spread to 217 countries infecting more than 86,255,226 cases and killing 1,863,973 people by the end of 2020. There are many reasons why bats are ideal reservoir hosts for viral diseases such as the tolerance of their immune system to the invading viruses for several months. They can actively shed the viruses, although they develop no clinical signs (will be discussed in details later in the review). Bats were directly or indirectly involved in the three previous coronavirus epidemics. The indirect transmission takes place via intermediate hosts including civet cats for SARS and dromedary camels in the case of MERS. Although bats are believed to be the source of COVID-19 pandemic, direct pieces of evidence are still lacking. Therefore, coronaviruses' role in epidemics induction and the epidemiological role of bats are discussed. The current work also presents different evidence (phylogenetic data, animal experiments, bats artificial infection studies, and computerized models of SARS-CoV2 evolution) that underline the involvement of bats in the epidemiology of the pandemic.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): a Systemic Infection

To date, seven identified coronaviruses (CoVs) have been found to infect humans; of these, three highly pathogenic variants have emerged in the 21st century. The newest member of this group, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first detected at the end of 2019 in Hubei province, China. Since then, this novel coronavirus has spread worldwide, causing a pandemic; the respiratory disease caused by the virus is called coronavirus disease 2019 (COVID-19). The clinical presentation ranges from asymptomatic to mild respiratory tract infections and influenza-like illness to severe disease with accompanying lung injury, multiorgan failure, and death. Although the lungs are believed to be the site at which SARS-CoV-2 replicates, infected patients often report other symptoms, suggesting the involvement of the gastrointestinal tract, heart, cardiovascular system, kidneys, and other organs; therefore, the following question arises: is COVID-19 a respiratory or systemic disease? This review aims to summarize existing data on the replication of SARS-CoV-2 in different tissues in both patients and ex vivo models.

SARS-CoV-2 innate effector associations and viral load in early nasopharyngeal infection

COVID‐19 causes severe disease with poor outcomes. We tested the hypothesis that early SARS‐CoV‐2 viral infection disrupts innate immune responses. These changes may be important for understanding subsequent clinical outcomes. We obtained residual nasopharyngeal swab samples from individuals who requested COVID‐19 testing for symptoms at drive‐through COVID‐19 clinical testing sites operated by the University of Utah. We applied multiplex immunoassays, real‐time polymerase chain reaction assays and quantitative proteomics to 20 virus‐positive and 20 virus‐negative samples. ACE‐2 transcripts increased with infection (OR =17.4, 95% CI [CI] =4.78–63.8) and increasing viral N1 protein transcript load (OR =1.16, CI =1.10–1.23). Transcripts for two interferons (IFN) were elevated, IFN‐λ1 (OR =71, CI =7.07–713) and IFN‐λ2 (OR =40.2, CI =3.86–419), and closely associated with viral N1 transcripts (OR =1.35, CI =1.23–1.49 and OR =1.33 CI =1.20–1.47, respectively). Only transcripts for IP‐10 were increased among systemic inflammatory cytokines that we examined (OR =131, CI =1.01–2620). We found widespread discrepancies between transcription and translation. IFN proteins were unchanged or decreased in infected samples (IFN‐γ OR =0.90 CI =0.33–0.79, IFN‐λ2,3 OR =0.60 CI =0.48–0.74) suggesting viral‐induced shut‐off of host antiviral protein responses. However, proteins for IP‐10 (OR =3.74 CI =2.07–6.77) and several interferon‐stimulated genes (ISG) increased with viral load (BST‐1 OR =25.1, CI =3.33–188; IFIT1 OR =19.5, CI =4.25–89.2; IFIT3 OR =245, CI =15–4020; MX‐1 OR =3.33, CI =1.44–7.70). Older age was associated with substantial modifications of some effects. Ambulatory symptomatic patients had an innate immune response with SARS‐CoV‐2 infection characterized by elevated IFN, proinflammatory cytokine and ISG transcripts, but there is evidence of a viral‐induced host shut‐off of antiviral responses. Our findings may characterize the disrupted immune landscape common in patients with early disease.

Severe Acute Respiratory Syndrome Coronavirus 2-Induced Immune Activation and Death of Monocyte-Derived Human Macrophages and Dendritic Cells

Studies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients and experimentally infected animals indicate a critical role for augmented expression of proinflammatory chemokines and cytokines in severe disease. Here, we demonstrate that SARS-CoV-2 infection of human monocyte-derived macrophages (MDMs) and monocyte-derived dendritic cells was abortive, but induced the production of multiple antiviral and proinflammatory cytokines (interferon-α, interferon-β, tumor necrosis factor, and interleukins 1β, 6, and 10) and a chemokine (CXCL10). Despite the lack of efficient replication in MDMs, SARS-CoV-2 induced profound interferon-mediated cell death of host cells. Macrophage activation and death were not enhanced by exposure to low levels of convalescent plasma, suggesting that antibody-dependent enhancement of infection does not contribute to cell death. Together, these results indicate that infection of macrophages and dendritic cells potentially plays a major role in coronavirus disease 2019 pathogenesis, even in the absence of productive infection.

[Neuroimmunology of COVID-19]

Zahlreiche neuroimmunologische Krankheitsbilder wie Enzephalopathien, Enzephalitiden, Myelitiden oder ADEM (akute disseminierte Enzephalomyelitis) sind nach einer Infektion mit SARS-CoV‑2 („severe acute respiratory syndrome coronavirus 2“) gehäuft aufgetreten, was für einen para- oder postinfektiösen Zusammenhang spricht. Ursächlich ist wahrscheinlich eine virusgetriggerte Überaktivierung des Immunsystems mit Hyperinflammation und Zytokin-Sturm, aber möglicherweise auch die Bildung spezifischer Autoantikörper gegen Gewebe des Zentralnervensystems, die sich vor allem im Liquor schwerkranker COVID-19(„coronavirus disease 2019“)-Patienten finden lassen. Eine direkte Schädigung durch die Invasion von SARS-CoV‑2 ins Gehirn oder Rückenmark scheint keine relevante Rolle zu spielen. Bei Patienten mit Multipler Sklerose, Myasthenie oder anderen neuroimmunologischen Krankheitsbildern wird die Anfälligkeit für eine SARS-CoV-2-Infektion sowie das Risiko eines schweren Verlaufs nicht durch die immunmodulierende Therapie bestimmt, sondern durch bekannte Risikofaktoren wie Alter, Komorbiditäten und den krankheitsbedingten Grad der Behinderung. Immuntherapien sollten bei diesen Patienten daher nicht verschoben oder pausiert werden. Inwieweit neuroimmunologische Mechanismen auch für Langzeitfolgen nach überstandener COVID-19-Erkrankung – wie Fatigue, Gedächtnis‑, Schlaf- oder Angststörungen – verantwortlich sind, werden klinische Verlaufsuntersuchungen u. a. in COVID-19-Registerstudien zeigen.

COVID-19: Immunology, Immunopathogenesis and Potential Therapies

The Coronavirus Disease-2019 (COVID-19) imposed public health emergency and affected millions of people around the globe. As of January 2021, 100 million confirmed cases of COVID-19 along with more than 2 million deaths were reported worldwide. SARS-CoV-2 infection causes excessive production of pro-inflammatory cytokines thereby leading to the development of "Cytokine Storm Syndrome." This condition results in uncontrollable inflammation that further imposes multiple-organ-failure eventually leading to death. SARS-CoV-2 induces unrestrained innate immune response and impairs adaptive immune responses thereby causing tissue damage. Thus, understanding the foremost features and evolution of innate and adaptive immunity to SARS-CoV-2 is crucial in anticipating COVID-19 outcomes and in developing effective strategies to control the viral spread. In the present review, we exhaustively discuss the sequential key immunological events that occur during SARS-CoV-2 infection and are involved in the immunopathogenesis of COVID-19. In addition to this, we also highlight various therapeutic options already in use such as immunosuppressive drugs, plasma therapy and intravenous immunoglobulins along with various novel potent therapeutic options that should be considered in managing COVID-19 infection such as traditional medicines and probiotics.

Pattern of genomic variation in SARS-CoV-2 (COVID-19) suggests restricted nonrandom changes: Analysis using Shewhart control charts

SARS-CoV-2 is a member of the Coronavirus family which recently originated from the Wuhan province of China and spread very rapidly through the world infecting more than 4 million people. In the past, other Coronaviruses have also been found to cause human infection, but not as widespread as COVID-19. Since Coronavirus sequences constantly change due to mutation and recombination, it is important to understand the pattern of changes and likely path the virus can take in the future. In this study, we have used the Shewhart control chart to identify and analyze hypervariable (hotspots) and hypovariable (coldspots) regions of the virus. Our analysis shows that SARS-CoV-2 has changed in a few regions of the genome. Analysis of SARS-CoV-1 and MERS sequences suggests that over time, mutations start accumulating in different regions and most likely SARS-CoV-2 may also follow a similar path. The results suggest a possible emergence of modified viruses over some time.

SARS-CoV-2: From the pathogenesis to potential anti-viral treatments

Introduction

The world is witnessing the spread of one of the members of Coronaviruses (CoVs) family, called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the 21st century. Considering the short time spent after its prevalence, limited information is known about the effect of the virus mechanism on different organs of the body; meanwhile the lack of specific treatment and vaccine for this virus has exposed millions of people to a big challenge.

Areas covered

The review article aims to describe the general and particular characteristics of CoVs, their classification, genome structure, host cell infection, cytokine storm, anti-viral treatments, and inhibition of COVID-19-related ER-mitochondrial stress. In addition, it refers to drugs such as Chloroquine/Hydroxychloroquine, Lopinavir/Ritonavir, darunavir, ribavirin, remdesivir, and favipiravir, which have undergone clinical trials for coronavirus disease 2019 (COVID-19) treatment. This analysis was derived from an extensive scientific literature search including Pubmed, ScienceDirect, and Google Scholar performed.

Expert opinion

The effectiveness rate and complications of these drugs can reveal new insights into the potential therapeutic goals for the disease. Moreover, lifestyle change can effectively prevent SARS-CoV-2 infection.

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.

Higher expression of monocyte chemotactic protein 1 in mild COVID-19 patients might be correlated with inhibition of Type I IFN signaling

BACKGROUND

Chemokine levels in severe coronavirus disease 2019 (COVID-19) patients have been shown to be markedly elevated. But the role of chemokines in mild COVID-19 has not yet been established. According to the epidemiological statistics, most of the COVID-19 cases in Shiyan City, China, have been mild. The purpose of this study was to evaluate the level of chemokines in mild COVID-19 patients and explore the correlation between chemokines and host immune response.

METHODS

In this study, we used an enzyme-linked immunosorbent assay to detect serum levels of chemokines in COVID-19 patients in Shiyan City. Expression of chemokine receptors and of other signaling molecules was measured by real-time polymerase chain reaction.

RESULTS

We first demonstrated that COVID-19 patients, both sever and mild cases, are characterized by higher level of chemokines. Specifically, monocyte chemotactic protein 1 (MCP-1) is expressed at higher levels both in severe and mild cases of COVID-19. The receptor of MCP-1, C-C chemokine receptor type 2, was expressed at higher levels in mild COVID-19 patients. Finally, we observed a significant negative correlation between expression levels of interferon (IFN) regulatory factor 3 (IRF3) and serum levels of MCP-1 in mild COVID-19 patients.

CONCLUSION

Higher expression of MCP-1 in mild COVID-19 patients might be correlated with inhibition of IFN signaling. The finding adds to our understanding of the immunopathological mechanisms of severe acute respiratory syndrome coronavirus 2 infection and provides potential therapeutic targets and strategies.

Epidemiology, virology, and history of Covid-19 infection

In this chapter, we will discuss the infection history and epidemiology, the viral structure of COVID 19 or SARS-CoV-2, mode of transmission, virulence, and pathogenesis of disease, and we also discuss how it was started and its relation to other coronaviruses. Then we will mention the relation to pregnancy, how it can affect pregnant female, sequelae on pregnancy course and labor, and effect on fetus and neonates.