Immune dysfunction leads to mortality and organ injury in patients with COVID-19 in China: insights from ERS-COVID-19 study

Immune cells are associated with mortality: the Health and Retirement Study

Introduction

Age-related immunosenescence is characterized by changes in immune cell subsets and is associated with mortality. However, since immunosenescence is associated with other concurrent age-related changes such as inflammation and multi-organ dysfunction, it is unclear whether the association between age-related immunosenescence and mortality is independent of other concurrent age-related changes. To address these limitations, we evaluated the independent association between immune cell subsets and mortality after adjustment for age-related inflammation and biologic age.

Methods

Data for this study was obtained from the 2016 interview of the Health and Retirement Study (N=6802). Cox proportional hazards regression models were used to estimate the association between 25 immune cell subsets (11 T-cell subsets, 4 B-cell subsets, 3 monocyte subsets, 3 natural killer cell subsets, 3 dendritic cell subsets, and neutrophils) and 4-year mortality adjusting for covariates such as the Klemera-Doubal algorithm biological age, chronological age, gender, race/ethnicity, BMI, smoking status, comorbidity index, CMV seropositivity, and inflammatory latent variable comprising C-reactive protein, and 4 cytokines (interleukin-10, interleukin-1 receptor antagonist, interleukin-6, and soluble tumor necrosis factor).

Results

Four hundred and seventy-six participants died during the study period with an overall median follow up time of 2.5 years. After controlling for covariates and adjustment for sample-weights, total T cells [HR: 0.86, p=0.004], NK CD56LO cells [HR: 0.88, p=0.005], and neutrophils [HR: 1.22, p=0.004] were significantly associated with mortality.

Conclusions

These findings support the idea that an aging immune system is associated with short-term mortality independent of age-related inflammation or other age-related measures of physiological dysfunction. If replicated in other external cohorts, these findings could identify novel targets for both monitoring and intervention to reduce the age-related mortality.

A brief overview of SARS-CoV-2 infection and its management strategies: a recent update

The COVID-19 pandemic has become a global health crisis, inflicting substantial morbidity and mortality worldwide. A diverse range of symptoms, including fever, cough, dyspnea, and fatigue, characterizes COVID-19. A cytokine surge can exacerbate the disease's severity. This phenomenon involves an increased immune response, marked by the excessive release of inflammatory cytokines like IL-6, IL-8, TNF-α, and IFNγ, leading to tissue damage and organ dysfunction. Efforts to reduce the cytokine surge and its associated complications have garnered significant attention. Standardized management protocols have incorporated treatment strategies, with corticosteroids, chloroquine, and intravenous immunoglobulin taking the forefront. The recent therapeutic intervention has also assisted in novel strategies like repurposing existing medications and the utilization of in vitro drug screening methods to choose effective molecules against viral infections. Beyond acute management, the significance of comprehensive post-COVID-19 management strategies, like remedial measures including nutritional guidance, multidisciplinary care, and follow-up, has become increasingly evident. As the understanding of COVID-19 pathogenesis deepens, it is becoming increasingly evident that a tailored approach to therapy is imperative. This review focuses on effective treatment measures aimed at mitigating COVID-19 severity and highlights the significance of comprehensive COVID-19 management strategies that show promise in the battle against COVID-19.

Potential impact of combined influenza and pneumococcal vaccines on the severity of respiratory illness in COVID-19 infection among type 2 diabetic patients

To retrospectively assess the impact of regular yearly administration of recombinant influenza and single administration of pneumococcal conjugate vaccines on the occurrence of serious respiratory infection including COVID-19 in patients with type 2 diabetes mellitus. Hundred patients with type 2 diabetes mellitus were given Vaxigrip and Prevnar13^® vaccines and were evaluated by comprehensive clinical review, airflow screening questionnaire, and routine laboratory investigations with follow-up during the COVID-19 pandemic and compared to a control group of diabetic patients with the same inclusion criteria (n = 100). After Vaxigrip and Prevnar13, there is a significant improvement in respiratory symptoms and a decrease in the airflow screening questionnaire (p = 0.0001) with a significant improvement in inflammatory parameters as neutrophil-lymphocyte ratio, ESR, CRP, and platelet count. Four patients had mild COVID-19 (4%), mainly gastrointestinal with no complications. Twenty-one out of 32 (65.6%) patients in the control group had severe COVID-19. The hazard ratios of significant respiratory tract infection and death due to COVID-19 were 2.29 and 10.24 in the non-vaccinated control (p = 0.001).The severity of COVID-19 in diabetes correlated with HBA1C (p = 0.007), combined Vaxigrip and Prevnar13 vaccination (p = 0.0001), serum creatinine (p = 0.001), neutrophil-lymphocyte ratio (p = 0.001), and thrombocytopenia (p = 0.003). The present study suggested that the combination of Prevnar13 and Vaxigrip may be related to decreased occurrence of serious respiratory infections including COVID-19. Further randomized control trials may be needed to establish a direct causation between the two and clarify these associations.

Aging, inflammaging and immunosenescence as risk factors of severe COVID-19

Coronavirus disease 2019 (COVID-19) is a respiratory infectious disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 is characterized by having a heterogeneous disease course, ranging from asymptomatic and mild symptoms to more severe and critical cases. In most cases the severity of COVID-19 is related to host factors, especially deregulation of the immune response in patients. Even if COVID-19 indiscriminately affects individuals of different age group, ethnicity and economic status; most severe cases and disproportional mortality occur in elderly individuals. This point out that aging is one risk factor for unfavourable clinical outcomes among COVID-19 patients. The biology of aging is a complex process; Aging can alter the structure and function of cells, tissues, and organs resulting in impaired response to stress. Alongside with other systems, the immune system is also affected with the aging process. Immunosenescence is an age associated change in the immune system that affects the overall response to immunological challenges in the elderly. Similarly, apart from the normal inflammatory process, aging is associated with a low grade, sterile, chronic inflammation which is termed as inflammaging. We hypothesized that inflammaging and immunosenescence could play an important role in SARS-CoV-2 pathogenesis and poor recovery from COVID-19 in elderly individuals. This review summarizes the changes in the immune system with age and how these changes play part in the pathogenesis of SARS-CoV-2 and clinical outcome of COVID-19 which could add to the understanding of age associated targeted immunotherapy in the elderly.

Leukocyte metabolism in obese type 2 diabetic individuals associated with COVID-19 severity

Recent studies show that the metabolic characteristics of different leukocytes, such as, lymphocytes, neutrophils, and macrophages, undergo changes both in the face of infection with SARS-CoV-2 and in obesity and type 2 diabetes mellitus (DM2) condition. Thus, the objective of this review is to establish a correlation between the metabolic changes caused in leukocytes in DM2 and obesity that may favor a worse prognosis during SARS-Cov-2 infection. Chronic inflammation and hyperglycemia, specific and usual characteristics of obesity and DM2, contributes for the SARS-CoV-2 replication and metabolic disturbances in different leukocytes, favoring the proinflammatory response of these cells. Thus, obesity and DM2 are important risk factors for pro-inflammatory response and metabolic dysregulation that can favor the occurrence of the cytokine storm, implicated in the severity and high mortality risk of the COVID-19 in these patients.

Coronavirus Host Genomics Study: South Africa (COVIGen-SA)

Host genetic factors are known to modify the susceptibility, severity, and outcomes of COVID-19 and vary across populations. However, continental Africans are yet to be adequately represented in such studies despite the importance of genetic factors in understanding Africa's response to the pandemic. We describe the development of a research resource for coronavirus host genomics studies in South Africa known as COVIGen-SA-a multicollaborator strategic partnership designed to provide harmonised demographic, clinical, and genetic information specific to Black South Africans with COVID-19. Over 2,000 participants have been recruited to date. Preliminary results on 1,354 SARS-CoV-2 positive participants from four participating studies showed that 64.7% were female, 333 had severe disease, and 329 were people living with HIV. Through this resource, we aim to provide insights into host genetic factors relevant to African-ancestry populations, using both genome-wide association testing and targeted sequencing of important genomic loci. This project will promote and enhance partnerships, build skills, and develop resources needed to address the COVID-19 burden and associated risk factors in South African communities.

IL-6 drives T cell death to participate in lymphopenia in COVID-19

Lymphopenia is a common observation in patients with COVID-19. To explore the cause of T cell lymphopenia in the disease, laboratory results of 64 hospitalized COVID-19 patients were retrospectively analyzed and six patients were randomly selected to trace their changes of T lymphocytes and plasma concentration of IL-6 for the course of disease. Results confirmed that the T-cell lymphopenia, especially CD4⁺ T cell reduction in COVID-19 patients, was a reliable indicator of severity and hospitalization in infected patients. And CD4⁺ T cell count below 200 cells/μL predicts critical illness in COVID-19 patients. In vitro assay supported that exposure to key contributors (IL-1β, IL-6, TNF-α and IFN-γ) of COVID-19 cytokine storm caused substantial death of activated T cells. Among these contributors, IL-6 level was found to probably reversely correlate with T cell counts in patients. And IL-6 alone was potent to induce T cell reduction by gasderminE-mediated pyroptosis, inferring IL-6 took a part in affecting the function and status of T cells in COVID-19 patients. Intervention of IL-6 mediated T cell pryprotosis may effectively delay disease progression, maintain normal immune status at an early stage of infection.

Dysregulation of immunity in COVID-19 and SLE

The immune response plays a crucial role in preventing diseases, such as infections. There are two types of immune responses, specific and innate immunity, each of which consists of two components: cellular immunity and humoral immunity. Dysfunction in any immune system component increases the risk of developing certain diseases. Systemic lupus erythematosus (SLE), an autoimmune disease in the human body, develops an immune response against its own components. In these patients, due to underlying immune system disorders and receipt of immunosuppressive drugs, the susceptibility to infections is higher than in the general population and is the single largest cause of mortality in this group. COVID-19 infection, which first appeared in late 2019, has caused several concerns in patients with SLE. However, there is no strong proof of additional risk of developing COVID-19 in patients with SLE, and in some cases, studies have shown less severity of the disease in these individuals. This review paper discusses the immune disorders in SLE and COVID-19.

The Role of Lymphocyte Subsets, PD-1, and FAS (CD95) in COVID-19 Cancer Patients

Lymphocytes are the main orchestrators that regulate the immune response in SARS-COV-2 infection. The exhaustion of T lymphocytes is a contributing factor to lymphopenia, which is responsible for the COVID-19 adverse outcome. However, it is still not demonstrated on a large scale, including cancer patients. Peripheral blood samples were obtained from 83 SARS-CoV2 infected cancer patients, and 29 COVID-19 infected noncancer patients compared to 28 age-matched healthy controls. Lymphocyte subsets were assessed for CD3, CD4, CD8, CD56, PD-1, and CD95 using flow cytometry. The data were correlated to the patients' clinical features, COVID-19 severity and outcomes. Lymphopenia, and decreased CD4⁺ T cells and CD8⁺ T cells were significantly observed in COVID-19 cancer and noncancer patients compared to the control group (p < 0.001, for all). There was a significantly increased expression of CD95 and PD-1 on the NK cells, CD4⁺ T cells, and CD8⁺ T cells in COVID-19 cancer and noncancer patients in comparison to the control group. The increased expression of CD95 on CD8⁺ T cells, as well as the increased expression of PD-1 on CD8⁺ T cells and NK cells are significantly associated with the severity of COVID-19 infection in cancer patients. The increased expression of CD95 and PD-1 on the CD4⁺ T cells, CD8⁺ T cells, and NK cells was observed significantly in nonsurviving patients and those who were admitted to the intensive care unit in COVID-19 cancer and noncancer patients. The increased expression of PD-1 and CD95 could be possible prognostic factors for COVID-19 severity and adverse outcomes in COVID-19 cancer and noncancer patients.

Mechanism of COVID-19 Causing ARDS: Exploring the Possibility of Preventing and Treating SARS-CoV-2

Novel coronavirus pneumonia (COVID-19) is spreading worldwide, causing great harm and stress to humans. Since patients with novel coronavirus (SARS-CoV-2) have a high probability of developing acute respiratory distress syndrome (ARDS) in severe cases, the pathways through which SARS-CoV-2 causes lung injury have become a major concern in the scientific field. In this paper, we investigate the relationship between SARS-CoV-2 and lung injury and explore the possible mechanisms of COVID-19 in ARDS from the perspectives of angiotensin-converting enzyme 2 protein, cytokine storm, activation of the immune response, triggering of Fas/FasL signaling pathway to promote apoptosis, JAK/STAT pathway, NF-κB pathway, type I interferon, vitamin D, and explore the possibility of prevention and treatment of COVID-19. To explore the possibility of SARS-CoV-2, and to provide new ideas to stop the development of ARDS in COVID-19 patients.

Therapeutic monoclonal antibodies for COVID-19 management: an update

BACKGROUND

The first case of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral disease in the world was announced on 31^st December 2019 in Wuhan, China. Since then, this virus has affected more than 440 million people, and today the world is facing different mutant strains of the virus, leading to increased morbidity rates, fatality rates, and surfacing re-infections. Various therapies, such as prophylactic treatments, repurposed drug treatments, convalescent plasma, and polyclonal antibody therapy have been developed to help combat the coronavirus disease 2019 (COVID-19).

AREA COVERED

This review article provides insights into the basic aspects of monoclonal antibodies (mAbs) for the therapy of COVID-19, as well as its advancement in terms of clinical trial and current approval status.

EXPERT OPINION

Monoclonal antibodies represents the most effective and viable therapy and/or prophylaxis option against COVID-19, and have shown a reduction of the viral load, as well as lowering hospitalizations and death rates. In different countries, various mAbs are undergoing different phases of clinical trials, with a few of them having entered phases III and IV. Due to the soaring number of cases worldwide, the FDA has given emergency approval for the mAb combinations bamlanivimab with etesevimab and casirivimab with imdevimab.

Off-the-shelf CAR natural killer cells secreting IL-15 target spike in treating COVID-19

Engineered natural killer (NK) cells represent a promising option for immune therapy option due to their immediate availability in allogeneic settings. Severe acute diseases, such as COVID-19, require targeted and immediate intervention. Here we show engineering of NK cells to express (1) soluble interleukin-15 (sIL15) for enhancing their survival and (2) a chimeric antigen receptor (CAR) consisting of an extracellular domain of ACE2, targeting the spike protein of SARS-CoV-2. These CAR NK cells (mACE2-CAR_sIL15 NK cells) bind to VSV-SARS-CoV-2 chimeric viral particles as well as the recombinant SARS-CoV-2 spike protein subunit S1 leading to enhanced NK cell production of TNF-α and IFN-γ and increased in vitro and in vivo cytotoxicity against cells expressing the spike protein. Administration of mACE2-CAR_sIL15 NK cells maintains body weight, reduces viral load, and prolongs survival of transgenic mice expressing human ACE2 upon infection with live SARS-CoV-2. These experiments, and the capacity of mACE2-CAR_sIL15 NK cells to retain their activity following cryopreservation, demonstrate their potential as an allogeneic off-the-shelf therapy for COVID-19 patients who are faced with limited treatment options.

Severe COVID-19 requires immediate and targeted intervention that is efficient against SARS-CoV-2 and its variants. Authors show here the therapeutic potential of engineered natural killer cells that simultaneously express a chimeric antigen receptor targeting the spike protein of SARS-CoV-2, and IL-15, a cytokine that enhances the function and survival of their own.

Surviving the Storm: Cytokine Biosignature in SARS-CoV-2 Severity Prediction

Simple Summary

The world has been stricken mentally, physically, and economically by the COVID-19 virus. However, while SARS-CoV-2 viral infection results in mild flu-like symptoms in most patients, a number of those infected develop severe illness. These patients require hospitalization and intensive care. The severe disease can spiral downwards with eventual severe damage to the lungs and failure of multiple organs, leading to the individual’s demise. It is necessary to identify those who are developing a severe form of illness to provide early management. Therefore, it is crucial to learn about the mechanisms and chemical mediators that lead to critical conditions in SARS-CoV-2 infection. This paper reviews studies regarding the individual chemical mediators, pathways, and means that contribute to worsening health conditions in SARS-CoV-2 infection.

Abstract

A significant part of the world population has been affected by the devastating SARS-CoV-2 infection. It has deleterious effects on mental and physical health and global economic conditions. Evidence suggests that the pathogenesis of SARS-CoV-2 infection may result in immunopathology such as neutrophilia, lymphopenia, decreased response of type I interferon, monocyte, and macrophage dysregulation. Even though most individuals infected with the SARS-CoV-2 virus suffer mild symptoms similar to flu, severe illness develops in some cases, including dysfunction of multiple organs. Excessive production of different inflammatory cytokines leads to a cytokine storm in COVID-19 infection. The large quantities of inflammatory cytokines trigger several inflammation pathways through tissue cell and immune cell receptors. Such mechanisms eventually lead to complications such as acute respiratory distress syndrome, intravascular coagulation, capillary leak syndrome, failure of multiple organs, and, in severe cases, death. Thus, to devise an effective management plan for SARS-CoV-2 infection, it is necessary to comprehend the start and pathways of signaling for the SARS-CoV-2 infection-induced cytokine storm. This article discusses the current findings of SARS-CoV-2 related to immunopathology, the different paths of signaling and other cytokines that result in a cytokine storm, and biomarkers that can act as early signs of warning for severe illness. A detailed understanding of the cytokine storm may aid in the development of effective means for controlling the disease’s immunopathology. In addition, noting the biomarkers and pathophysiology of severe SARS-CoV-2 infection as early warning signs can help prevent severe complications.

COVID-19 Vaccines: Current and Future Perspectives

Currently available vaccines against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are highly effective but not able to keep the coronavirus disease 2019 (COVID-19) pandemic completely under control. Alternative R&D strategies are required to induce a long-lasting immunological response and to reduce adverse events as well as to favor rapid development and large-scale production. Several technological platforms have been used to develop COVID-19 vaccines, including inactivated viruses, recombinant proteins, DNA- and RNA-based vaccines, virus-vectored vaccines, and virus-like particles. In general, mRNA vaccines, protein-based vaccines, and vectored vaccines have shown a high level of protection against COVID-19. However, the mutation-prone nature of the spike (S) protein affects long-lasting vaccine protection and its effectiveness, and vaccinated people can become infected with new variants, also showing high virus levels. In addition, adverse effects may occur, some of them related to the interaction of the S protein with the angiotensin-converting enzyme 2 (ACE-2). Thus, there are some concerns that need to be addressed and challenges regarding logistic problems, such as strict storage at low temperatures for some vaccines. In this review, we discuss the limits of vaccines developed against COVID-19 and possible innovative approaches.

Repurposing Multiple-Molecule Drugs for COVID-19-Associated Acute Respiratory Distress Syndrome and Non-Viral Acute Respiratory Distress Syndrome via a Systems Biology Approach and a DNN-DTI Model Based on Five Drug Design Specifications

The coronavirus disease 2019 (COVID-19) epidemic is currently raging around the world at a rapid speed. Among COVID-19 patients, SARS-CoV-2-associated acute respiratory distress syndrome (ARDS) is the main contribution to the high ratio of morbidity and mortality. However, clinical manifestations between SARS-CoV-2-associated ARDS and non-SARS-CoV-2-associated ARDS are quite common, and their therapeutic treatments are limited because the intricated pathophysiology having been not fully understood. In this study, to investigate the pathogenic mechanism of SARS-CoV-2-associated ARDS and non-SARS-CoV-2-associated ARDS, first, we constructed a candidate host-pathogen interspecies genome-wide genetic and epigenetic network (HPI-GWGEN) via database mining. With the help of host-pathogen RNA sequencing (RNA-Seq) data, real HPI-GWGEN of COVID-19-associated ARDS and non-viral ARDS were obtained by system modeling, system identification, and Akaike information criterion (AIC) model order selection method to delete the false positives in candidate HPI-GWGEN. For the convenience of mitigation, the principal network projection (PNP) approach is utilized to extract core HPI-GWGEN, and then the corresponding core signaling pathways of COVID-19-associated ARDS and non-viral ARDS are annotated via their core HPI-GWGEN by KEGG pathways. In order to design multiple-molecule drugs of COVID-19-associated ARDS and non-viral ARDS, we identified essential biomarkers as drug targets of pathogenesis by comparing the core signal pathways between COVID-19-associated ARDS and non-viral ARDS. The deep neural network of the drug–target interaction (DNN-DTI) model could be trained by drug–target interaction databases in advance to predict candidate drugs for the identified biomarkers. We further narrowed down these predicted drug candidates to repurpose potential multiple-molecule drugs by the filters of drug design specifications, including regulation ability, sensitivity, excretion, toxicity, and drug-likeness. Taken together, we not only enlighten the etiologic mechanisms under COVID-19-associated ARDS and non-viral ARDS but also provide novel therapeutic options for COVID-19-associated ARDS and non-viral ARDS.

Systems analysis of immune responses to attenuated P. falciparum malaria sporozoite vaccination reveals excessive inflammatory signatures correlating with impaired immunity

Immunization with radiation-attenuated sporozoites (RAS) can confer sterilizing protection against malaria, although the mechanisms behind this protection are incompletely understood. We performed a systems biology analysis of samples from the Immunization by Mosquito with Radiation Attenuated Sporozoites (IMRAS) trial, which comprised P. falciparum RAS-immunized (PfRAS), malaria-naive participants whose protection from malaria infection was subsequently assessed by controlled human malaria infection (CHMI). Blood samples collected after initial PfRAS immunization were analyzed to compare immune responses between protected and non-protected volunteers leveraging integrative analysis of whole blood RNA-seq, high parameter flow cytometry, and single cell CITEseq of PBMCs. This analysis revealed differences in early innate immune responses indicating divergent paths associated with protection. In particular, elevated levels of inflammatory responses early after the initial immunization were detrimental for the development of protective adaptive immunity. Specifically, non-classical monocytes and early type I interferon responses induced within 1 day of PfRAS vaccination correlated with impaired immunity. Non-protected individuals also showed an increase in Th2 polarized T cell responses whereas we observed a trend towards increased Th1 and T-bet+ CD8 T cell responses in protected individuals. Temporal differences in genes associated with natural killer cells suggest an important role in immune regulation by these cells. These findings give insight into the immune responses that confer protection against malaria and may guide further malaria vaccine development.

Trial registration: ClinicalTrials.gov NCT01994525.

Malaria remains a serious global health problem, causing hundreds of thousands of deaths every year. An effective malaria vaccine would be an important tool to fight this disease. Previous work has shown that irradiated sporozoites, the form of the malaria parasite injected into humans by mosquitos, are not capable of progressing to a symptomatic blood stage malaria infection, and act as a protective vaccine against future malaria exposure. However the mechanisms that produce this protection are unknown. In this work, we studied individuals vaccinated with irradiated sporozoites before being exposed to live malaria parasites. Roughly half of these individual were protected against malaria. By analyzing blood samples taken at multiple points after the first vaccination using RNA sequencing and flow cytometry we identified immune responses that differed between protected and non-protected study participants. Notably, we observed a rapid increase in inflammation and interferon-associated genes in non-protected individual. We also observed protection-associated changes in T cell and NK cell associated pathways. Our study provides novel insights into immune responses associated with effective malaria vaccination, and can point the way to improved design of whole-sporozoite malaria vaccine approaches.

Meta-Analysis and Systematic Review of the Thermal Stress Response: Gallus gallus domesticus Show Low Immune Responses During Heat Stress

Heat stress, which affects broiler growth performance and immunity, is a major concern in the poultry industry. This meta-analysis aimed to demonstrate the significant effect of heat stress on broiler mass gain and immunoglobulin levels, which regulates the mortality rate of broilers. A total of 2,585 studies were downloaded from PubMed, Web of Science, and Google Scholar from January 1, 2015, to September 1, 2021. Eventually, 28 studies were selected based on specific criteria. The results for body mass gain, total mass of immune organs (thymus, spleen, and bursa of Fabricius), immunoglobulin (IgA, IgG, and IgM) levels, and mortality rate were analyzed using odds ratio or the random-effects model (REM) at a confidence interval (CI) of 95%. Compared to the control, heat stress significantly decreased body mass gain (10 trials: REM = 1.35, 95% CI: 1.21, 1.50). Compared to that in the control, heat stress significantly increased immunoglobulin levels: IgA (7 trials: REM = 1.69, 95% CI: 0.90, 3.16), IgG (6 trials: REM = 1.24, 95% CI: 0.85, 1.81), IgM (8 trials: REM = 0.69, 95% CI: 0.44, 1.08), and heat stress also increased the broiler mortality rate (6 trials: REM = 0.06, 95% CI: 0.01, 0.27). However, there were no significant changes in the immune organs between the control and heat-stressed groups. In conclusion, heat stress remarkably alters the mass gain and immunoglobulin levels of broilers, which may be a cause of the high mortality rate.

Characteristics of peripheral white blood cells in COVID-19 patients revealed by a retrospective cohort study

Background

Peripheral hematological changes in severe COVID-19 patients may reflect the immune response during SARS-CoV-2 infection. Characteristics of peripheral white blood cells as early signals were needed to be investigated for clarifying its associations with the fatal outcomes in COVID-19 patients.

Methods

A retrospective cohort study was performed and the hospitalized COVID-19 patients were recruited in wards of Sino-French New City Branch of Tongji Hospital in Wuhan, Hubei province, China. Characteristics of peripheral white blood cells in survivors and non-survivors were analyzed. Comparison among patients with different level of eosinophils was performed.

Results

Of 198 patients included in this study, 185 were discharged and 13 died. Levels of eosinophils, lymphocytes and basophils in non-survivors were significantly lower than those in survivors. Death rate in low eosinophils group was higher and no patient died in normal eosinophils group (16.7% vs 0, P < 0.001). The proportion of patients in low eosinophils group who used glucocorticoids was higher than in normal eosinophils group, but glucocorticoids usage was not an indicator for death in subgroup analysis in low eosinophils patients. Moreover, positive correlation was found between the counts of lymphocytes and eosinophils in patients with glucocorticoids use but not in patients without the treatment.

Conclusions

Hematological changes differed between survivors and non-survivors with COVID-19. Lymphopenia and eosinopenia could be predictors for poor prognosis of COVID-19 patients. Initial counts of eosinophils may guide us in usage of glucocorticoids for COVID-19 treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06899-7.

Immune response variables and viral mutations impact on COVID-19 reinfection and relapse

The possibility of human reinfection with SARS-CoV-2, the coronavirus responsible for COVID-19, has not previously been thoroughly investigated. Although it is generally believed that virus-specific antibodies protect against COVID-19 pathogenesis, their duration of function and temporal activity remain unknown. Contrary to media reports that people retain protective antibody responses for a few months, science does not exclude reinfection and disease relapse shortly after initiating all immune responses during the primary onset of COVID-19. Despite production of antiviral antibodies, activated CD4+/CD8+ lymphocytes, and long-lived memory B cells, susceptibility to reinfection in humans for extended periods cannot be precluded due to repeated exposures to coronavirus or potential reactivation of the virus due to incomplete virus clearance. However, the mechanism of reinfection remains unknown. The biological characteristics of SARS-CoV-2, such as emergence of multiple mutations in the virus RNA molecules, transmissibility, rates of infection, reactivation and reinfection, can all affect the trajectory of the virus spread. Innate and adaptive immune response variables, differences in underlying diseases, and comorbidities, particularly in high risk individuals, can influence the dynamics of the virus infection. In this article, immune parameters and viral mutations pertaining to reinfection and disease relapse are reviewed and scientific gaps are discussed.

Can prognostic nutritional index and systemic immune-inflammatory index predict disease severity in COVID-19?

BACKGROUND

Prognostic nutritional index (PNI) and systemic immune-inflammatory index (SII) are inflammation-based novel markers that predict the prognosis in various patient populations. We have investigated the relationship between the disease severity in COVID-19, and the PNI and SII scores in the present study.

MATERIALS AND METHODS

This cross-sectional retrospective study included 118 hospitalised patients with a confirmed diagnosis of COVID-19. The patients were divided into two groups as those who were hospitalised at the intensive care unit (ICU) and those who had been internalised at the clinic (non-ICU).

RESULTS

Of the 118 patients, 50.8% were male. The mean age was 57.7 ± 17.5 years in non-ICU patients and 70.3 ± 11.7 years in ICU patients and the difference was statistically significant (P < .001). The lymphocyte count and the albumin levels were significantly lower in ICU patients (P < .001, P < .001, respectively). The PNI score was significantly lower in ICU patients compared with non-ICU patients (P < .001). The SII score was found to be significantly higher in ICU patients compared with non-ICU patients (P < .001). The value of PNI and SII scores in prediction of the disease severity in COVID-19 was evaluated with the ROC analysis (PNI: AUC = 0.796, 95%CI: 0.715-0.877, P < .001; SII: AUC =0.689, 95% CI: 0.559-0.819, P=.004). When the cut-off value was taken as ≤36.7 for the PNI score, it was found to have 73.4% sensitivity and 70.8% specificity for predicting of the disease severity and ICU admission probability was 4.4 times higher. When the cut-off value was taken as ≥813.6 for SII score, it was found to have 70.8% sensitivity and 66.0% specificity for predicting of the disease severity and ICU admission probability was six times higher.

CONCLUSION

The PNI and the SII scores are independent predictors of the prognosis and the disease severity in COVID-19 patients who require hospitalisation at the ICU.

Imbalanced Immune Response of T-Cell and B-Cell Subsets in Patients with Moderate and Severe COVID-19

BACKGROUND

The immunological changes associated with COVID-19 are largely unknown.

METHODS

Patients with COVID-19 showing moderate (n = 18; SpO2 > 93%, respiratory rate > 22 per minute, CRP > 10 mg/L) and severe (n = 23; SpO₂ < 93%, respiratory rate >30 per minute, PaO₂/FiO₂ ≤ 300 mmHg, permanent oxygen therapy, qSOFA > 2) infection, and 37 healthy donors (HD) were enrolled. Circulating T- and B-cell subsets were analyzed by flow cytometry.

RESULTS

CD4+Th cells were skewed toward Th2-like phenotypes within CD45RA+CD62L- (CM) and CD45RA-CD62L- (EM) cells in patients with severe COVID-19, while CM CCR6+ Th17-like cells were decreased if compared with HD. Within CM Th17-like cells "classical" Th17-like cells were increased and Th17.1-like cells were decreased in severe COVID-19 cases. Circulating CM follicular Th-like (Tfh) cells were decreased in all COVID-19 patients, and Tfh17-like cells represented the most predominant subset in severe COVID-19 cases. Both groups of patients showed increased levels of IgD-CD38++ B cells, while the levels of IgD+CD38- and IgD-CD38- were decreased. The frequency of IgD+CD27+ and IgD-CD27+ B cells was significantly reduced in severe COVID-19 cases.

CONCLUSIONS

We showed an imbalance within almost all circulating memory Th subsets during acute COVID-19 and showed that altered Tfh polarization led to a dysregulated humoral immune response.

Case series of COVID-19 patients from the Qinghai-Tibetan Plateau Area in China

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a serious infection caused by the new coronavirus severe acute respiratory syndrome coronavirus 2. The disease was first identified in December 2019 and has caused significant morbidity and mortality worldwide.

AIM

To explore the clinical characteristics and treatments for COVID-19 in the Qinghai-Tibetan Plateau Area in China.

METHODS

We retrospectively analyzed the blood cell counts (neutrophils and lymphocytes), blood gas analysis, and thoracic computed tomography changes of patients from Qinghai Province before, during, and after treatment (January 23, 2020 to February 21, 2020). In addition, we summarized and analyzed the information of critical patients. All data were analyzed using SPSS 17.0 (SPSS Inc., Chicago, IL, United States). The quantitative and count variables are represented as the mean ± SD and n (%), respectively.

RESULTS

The main symptoms and signs of patients with COVID-19 were fever, dry cough, cough with phlegm, difficulty breathing, and respiratory distress with a respiration rate ≥ 30 times/min, finger oxygen saturation ≤ 93% in the resting state, and oxygenation index less than 200 but greater than 100 (after altitude correction). Eighteen patients with COVID-19, of whom three were critical, and the others were in a mild condition, were included. The main manifestations included fever, dry cough, and fatigue. Three patients developed difficulty breathing and had a fever. They were eventually cured and discharged. Adjuvant examinations showed one case with reduced white cell count (6%) (< 4 × 109/L), six with reduced count of lymphocytes (33%) (< 0.8 × 109/L), and one with abnormal blood glucose level. All 18 patients were discharged, and no death occurred.

CONCLUSION

Our findings provide critical insight into assessing the clinical diagnosis and treatment for COVID-19 in the Tibetan plateau area.

Immunological parameters associated with the severity of COVID-19 pneumonia in kidney transplant recipients

Purpose

An outbreak of a novel respiratory disease due to coronavirus species was emerged in 2019 and named as Coronavirus Disease-2019 (COVID-19). Clinical and immunological factors affecting the course of COVID-19 in kidney transplant recipients (KTR) are not well-known.

Methods

In this prospective observational study, we presented 20 KTR with COVID-19 pnemonia and examined the factors predicting the severity of COVID-19. A total of 10 KTR without COVID-19 was used as control group. Lymphocyte subsets were determined by flow cytometry. In 13/20 patients, immunophenotyping was repeated 1 week later.

Results

Mean age of the patients was 50 ± 9 years. Patients were classified as mild–moderate (oxygen saturation: SO₂ > 90%) and severe disease groups (SO₂ ≤ 90%). Serum albumin and hemoglobin were lower and CRP, fibrinogen and peak d-dimer were higher in severe group. Peak CRP was inversely associated with nadir SO₂ (r =  − 0.68, p = 0.001). Neutrophil/lymphocyte ratio was higher in severe group (p = 0.01). CD3 + and CD4 + cells were lower and NK cell percentage (CD16 + 56 +) was higher in severe group. Percentage of spontaneously activated CD8 cells (CD8 + CD69 +) was higher in severe group. In comparison of KTR with and without COVID-19, CD8 + cells were lower but NK cell percentage was higher in KTR with COVID-19.

Conclusion

In this pilot study, increased NK cells, activated CD8 + cells and decreased CD3 + and CD4 + cells were associated with severity of COVID-19 in KTR. Peripheral immunophenotyping of lymphocyte subtypes may provide prognostic information about the clinical course of COVID-19 in KTR.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-021-02947-y.

Evidence of Long-Lasting Humoral and Cellular Immunity against SARS-CoV-2 Even in Elderly COVID-19 Convalescents Showing a Mild to Moderate Disease Progression

We here evaluate the humoral and cellular immune response against SARS-CoV-2 in 41 COVID-19 convalescents. As previous studies mostly included younger individuals, one advantage of our study is the comparatively high mean age of the convalescents included in the cohort considered (54 ± 8.4 years). While anti-SARS-CoV-2 antibodies were still detectable in 95% of convalescents up to 8 months post infection, an antibody-decay over time was generally observed in most donors. Using a multiplex assay, our data additionally reveal that most convalescents exhibit a broad humoral immunity against different viral epitopes. We demonstrate by flow cytometry that convalescent donors show a significantly elevated number of natural killer cells when compared to healthy controls, while no differences were found concerning other leucocyte subpopulations. We detected a specific long-lasting cellular immune response in convalescents by stimulating immune cells with SARS-CoV-2-specific peptides, covering domains of the viral spike, membrane and nucleocapsid protein, and measuring interferon-γ (IFN-γ) release thereafter. We modified a commercially available ELISA assay for IFN-γ determination in whole-blood specimens of COVID-19 convalescents. One advantage of this assay is that it does not require special equipment and can, thus, be performed in any standard laboratory. In conclusion, our study adds knowledge regarding the persistence of immunity of convalescents suffering from mild to moderate COVID-19. Moreover, our study provides a set of simple methods to characterize and confirm experienced COVID-19.

Impaired immune response mediated by prostaglandin E2 promotes severe COVID-19 disease

The SARS-CoV-2 coronavirus has led to a pandemic with millions of people affected. The present study finds that risk-factors for severe COVID-19 disease courses, i.e. male sex, older age and sedentary life style are associated with higher prostaglandin E2 (PGE2) serum levels in blood samples from unaffected subjects. In COVID-19 patients, PGE2 blood levels are markedly elevated and correlate positively with disease severity. SARS-CoV-2 induces PGE2 generation and secretion in infected lung epithelial cells by upregulating cyclo-oxygenase (COX)-2 and reducing the PG-degrading enzyme 15-hydroxyprostaglandin-dehydrogenase. Also living human precision cut lung slices (PCLS) infected with SARS-CoV-2 display upregulated COX-2. Regular exercise in aged individuals lowers PGE2 serum levels, which leads to increased Paired-Box-Protein-Pax-5 (PAX5) expression, a master regulator of B-cell survival, proliferation and differentiation also towards long lived memory B-cells, in human pre-B-cell lines. Moreover, PGE2 levels in serum of COVID-19 patients lowers the expression of PAX5 in human pre-B-cell lines. The PGE2 inhibitor Taxifolin reduces SARS-CoV-2-induced PGE2 production. In conclusion, SARS-CoV-2, male sex, old age, and sedentary life style increase PGE2 levels, which may reduce the early anti-viral defense as well as the development of immunity promoting severe disease courses and multiple infections. Regular exercise and Taxifolin treatment may reduce these risks and prevent severe disease courses.

Community- versus hospital-acquired acute kidney injury in hospitalised COVID-19 patients

Background

Acute kidney injury (AKI) is a recognised complication of coronavirus disease 2019 (COVID-19), yet the reported incidence varies widely and the associated risk factors are poorly understood.

Methods

Data was collected on all adult patients who returned a positive COVID-19 swab while hospitalised at a large UK teaching hospital between 1st March 2020 and 3rd June 2020. Patients were stratified into community- and hospital-acquired AKI based on the timing of AKI onset.

Results

Out of the 448 eligible patients with COVID-19, 118 (26.3 %) recorded an AKI during their admission. Significant independent risk factors for community-acquired AKI were chronic kidney disease (CKD), diabetes, clinical frailty score and admission C-reactive protein (CRP), systolic blood pressure and respiratory rate. Similar risk factors were significant for hospital-acquired AKI including CKD and trough systolic blood pressure, peak heart rate, peak CRP and trough lymphocytes during admission. In addition, invasive mechanical ventilation was the most significant risk factor for hospital-acquired AKI (adjusted odds ratio 9.1, p < 0.0001) while atrial fibrillation conferred a protective effect (adjusted odds ratio 0.29, p < 0.0209). Mortality was significantly higher for patients who had an AKI compared to those who didn’t have an AKI (54.3 % vs. 29.4 % respectively, p < 0.0001). On Cox regression, hospital-acquired AKI was significantly associated with mortality (adjusted hazard ratio 4.64, p < 0.0001) while community-acquired AKI was not.

Conclusions

AKI occurred in over a quarter of our hospitalised COVID-19 patients. Community- and hospital-acquired AKI have many shared risk factors which appear to converge on a pre-renal mechanism of injury. Hospital- but not community acquired AKI was a significant risk factor for death.

The signal pathways and treatment of cytokine storm in COVID-19

The Coronavirus Disease 2019 (COVID-19) pandemic has become a global crisis and is more devastating than any other previous infectious disease. It has affected a significant proportion of the global population both physically and mentally, and destroyed businesses and societies. Current evidence suggested that immunopathology may be responsible for COVID-19 pathogenesis, including lymphopenia, neutrophilia, dysregulation of monocytes and macrophages, reduced or delayed type I interferon (IFN-I) response, antibody-dependent enhancement, and especially, cytokine storm (CS). The CS is characterized by hyperproduction of an array of pro-inflammatory cytokines and is closely associated with poor prognosis. These excessively secreted pro-inflammatory cytokines initiate different inflammatory signaling pathways via their receptors on immune and tissue cells, resulting in complicated medical symptoms including fever, capillary leak syndrome, disseminated intravascular coagulation, acute respiratory distress syndrome, and multiorgan failure, ultimately leading to death in the most severe cases. Therefore, it is clinically important to understand the initiation and signaling pathways of CS to develop more effective treatment strategies for COVID-19. Herein, we discuss the latest developments in the immunopathological characteristics of COVID-19 and focus on CS including the current research status of the different cytokines involved. We also discuss the induction, function, downstream signaling, and existing and potential interventions for targeting these cytokines or related signal pathways. We believe that a comprehensive understanding of CS in COVID-19 will help to develop better strategies to effectively control immunopathology in this disease and other infectious and inflammatory diseases.

Promising role of curcumin against viral diseases emphasizing COVID-19 management: A review on the mechanistic insights with reference to host-pathogen interaction and immunomodulation

Curcumin has already acknowledged immense interest from both medical and scientific research because of its multifaceted activity. To date, the promising effects of curcumin were perceived against numerous inflammatory diseases. Besides, curcumin's role as a medicine has been studied in many virus infections like influenza, HIV, etc. There is a need to analyze the cellular mechanisms of curcumin including host-pathogen interaction and immunomodulatory effects, to explore the role of curcumin against COVID-19. With this background, our study suggests that curcumin can prevent COVID-19 infections by inhibiting the pathogen entry, viral genome replication and steps in the endosomal pathway along with inhibition of T-cell signalling by impairing the autophagy-mediated antigen-presenting pathway. This review explicit the possible mechanisms behind curcumin-induced cellular immunity and a therapeutive dosage of curcumin suggesting a preventive strategy against COVID-19.

Ambient air pollution and low temperature associated with case fatality of COVID-19: A nationwide retrospective cohort study in China

The evidence for the effects of environmental factors on COVID-19 case fatality remains controversial, and it is crucial to understand the role of preventable environmental factors in driving COVID-19 fatality. We thus conducted a nationwide cohort study to estimate the effects of environmental factors (temperature, particulate matter [PM_2.5, PM₁₀], sulfur dioxide [SO₂], nitrogen dioxide [NO₂], and ozone [O₃]) on COVID-19 case fatality. A total of 71,808 confirmed COVID-19 cases were identified and followed up for their vital status through April 25, 2020. Exposures to ambient air pollution and temperature were estimated by linking the city- and county-level monitoring data to the residential community of each participant. For each participant, two windows were defined: the period from symptom onset to diagnosis (exposure window I) and the period from diagnosis date to date of death/recovery or end of the study period (exposure window II). Cox proportional hazards models were used to estimate the associations between these environmental factors and COVID-19 case fatality. COVID-19 case fatality increased in association with environmental factors for the two exposure windows. For example, each 10 μg/m³ increase in PM_2.5, PM₁₀, O₃, and NO₂ in window I was associated with a hazard ratio of 1.11 (95% CI 1.09, 1.13), 1.10 (95% CI 1.08, 1.13), 1.09 (95 CI 1.03, 1.14), and 1.27 (95% CI 1.19, 1.35) for COVID-19 fatality, respectively. A significant effect was also observed for low temperature, with a hazard ratio of 1.03 (95% CI 1.01, 1.04) for COVID-19 case fatality per 1°C decrease. Subgroup analysis indicated that these effects were stronger in the elderly, as well as in those with mild symptoms and living in Wuhan or Hubei. Overall, the sensitivity analyses also yielded consistent estimates. Short-term exposure to ambient air pollution and low temperature during the illness would play a nonnegligible part in causing case fatality due to COVID-19. Reduced exposures to high concentrations of PM_2.5, PM₁₀, O₃, SO₂, and NO₂ and low temperature would help improve the prognosis and reduce public health burden.

Incidence of PTSD and generalized anxiety symptoms during the first wave of COVID-19 outbreak: an exploratory study of a large sample of the Italian population

BACKGROUND

During the COVID-19 pandemic, between March and May 2020, in Italy, people were asked to shelter in place and most had to put their life on hold, while news of the spread of the virus constantly were broadcasted. The change in habits and the potential exposure to a dangerous virus can be categorized as a catastrophic event, which are usually traumatic and therefore have psychological consequences for the people involved.

OBJECTIVE

Assuming the COVID-19 pandemic as a possible traumatic event, this study aims to explore the contingent behavioural and psychological impact of COVID-19 spread and related lockdown on the Italian general population, through measuring anxiety and post-traumatic stress symptoms .

METHODS

An ad hoc-survey was set up for the this exploratory research, including the standardized Italian versions of the Impact of Event Scale Revised (IES-R) and the Generalized Anxiety Scale (GAD-7), and ad hoc items concerning behavioural reactions due to the pandemic spread and related mass quarantine. Participants were recruited across convenient web-based and mobile app channels using a snowball sampling technique. Data was collected from March 25th to May 1st, 2020.

PARTICIPANTS

One-thousand one hundred and ninety-five individuals (851 women and 342 men) completed 60% or more of the survey and were considered for analyses. Mean age was 40 years (s.d. = 14.948). Participants resided in 78 Italian provinces (out of 107 territorial divisions), with 25.7% residing in the Milan province and 9.2% from the Monza and Brianza provinces, closest to the epicentre of the Italian outbreak.

RESULTS

During the worst months of the first wave of the Pandemic, the Italian population suffered high level of distress (GAD-7 m = 6.89, s.d. = 5.08; IER-R mean score = 27.86, s.d. 17.46), respectively indicating mild presence of anxiety symptoms, and high levels of PTSD symptoms. Gender seems to be a discriminating variable with women scoring significantly higher than man, both for anxiety symptoms (H (1) = 82.91, p < .001) and all dimensions of PTSD symptoms (intrusion H (1) = 71.23, p < .001, avoidance H (1) = 61.28, p < .001), and hyperarousal (H (1) = 67.348, p < .001). People from Generations Y and Z show to be at higher risk of developing PTSD (V = .746, F (3,1041) =1017.19, p = .001) and GAD symptoms (F (3,1041) = 5.113, p = .002) than older generations.

CONCLUSIONS

Gender and generation appeared to be the most consistent risk factor for higher levels of generalized anxiety and PTSD symptoms in the current pandemic. Other variables - such as information seeking behaviours, parental and marriage status, chronic conditions - yielded less consistent evidence. Results indicate the need of including psychological interventions as a standard tool during the emergency management of a catastrophic events such as a pandemic.

Enriched Opportunistic Pathogens Revealed by Metagenomic Sequencing Hint Potential Linkages between Pharyngeal Microbiota and COVID-19

As a respiratory tract virus, SARS-CoV-2 infected people through contacting with the upper respiratory tract first. Previous studies indicated that microbiota could modulate immune response against pathogen infection. In the present study, we performed metagenomic sequencing of pharyngeal swabs from eleven patients with COVID-19 and eleven Non-COVID-19 patients who had similar symptoms such as fever and cough. Through metagenomic analysis of the above two groups and a healthy group from the public data, there are 6502 species identified in the samples. Specifically, the Pielou index indicated a lower evenness of the microbiota in the COVID-19 group than that in the Non-COVID-19 group. Combined with the linear discriminant analysis (LDA) and the generalized linear model, eighty-one bacterial species were found with increased abundance in the COVID-19 group, where 51 species were enriched more than 8 folds. The top three enriched genera were Streptococcus, Prevotella and Campylobacter containing some opportunistic pathogens. More interestingly, through experiments, we found that two Streptococcus strains, S. suis and S. agalactiae, could stimulate the expression of ACE2 of Vero cells in vitro, which may promote SARS-CoV-2 infection. Therefore, these enriched pathogens in the pharynxes of COVID-19 patients may involve in the virus-host interactions to affect SARS-CoV-2 infection and cause potential secondary bacterial infections through changing the expression of the viral receptor ACE2 and/or modulate the host’s immune system.

Metabolomics reveals sex-specific metabolic shifts and predicts the duration from positive to negative in non-severe COVID-19 patients during recovery process

Metabolic profiling in COVID-19 patients has been associated with disease severity, but there is no report on sex-specific metabolic changes in discharged survivors. Herein we used an integrated approach of LC-MS-and GC-MS-based untargeted metabolomics to analyze plasma metabolic characteristics in men and women with non-severe COVID-19 at both acute period and 30 days after discharge. The results demonstrate that metabolic alterations in plasma of COVID-19 patients during the recovery and rehabilitation process were presented in a sex specific manner. Overall, the levels of most metabolites were increased in COVID-19 patients after the cure relative to acute period. The major plasma metabolic changes were identified including fatty acids in men and glycerophosphocholines and carbohydrates in women. In addition, we found that women had shorter length of hospitalization than men and metabolic characteristics may contribute to predict the duration from positive to negative in non-severe COVID-19 patients. Collectively, this study shed light on sex-specific metabolic shifts in non-severe COVID-19 patients during the recovery process, suggesting a sex bias in prognostic and therapeutic evaluations based on metabolic profiling.

Nanotechnology to the Rescue: Treatment Perspective for the Immune Dysregulation Observed in COVID-19

The study of the use of nanotechnology for drug delivery has been extensive. Nanomedical approaches for therapeutics; drug delivery in particular is superior to conventional methods in that it allows for controlled targeted delivery and release, higher stability, extended circulation time, minimal side-effects, and improved pharmacokinetic clearance (of the drug) form the body, to name a few. The magnitude of COVID-19, the current ongoing pandemic has been severe; it has caused widespread the loss of human life. In individuals with severe COVID-19, immune dysregulation and a rampant state of hyperinflammation is observed. This kind of an immunopathological response is detrimental and results in rapid disease progression, development of secondary infections, sepsis and can be fatal. Several studies have pin-pointed the reason for this immune dysregulation; deviations in the signaling pathways involved in the mediation and control of immune responses. In severe COVID-19 patients, many signaling cascades including JAK/STAT, NF-κB, MAPK/ERK, TGF beta, VEGF, and Notch signaling were found to be either upregulated or inactivated. Targeting these aberrant signaling pathways in conjunction with antiviral therapy will effectuate mitigation of the hyperinflammation, hypercytokinemia, and promote faster recovery. The science of the use of nanocarriers as delivery agents to modulate these signaling pathways is not new; it has already been explored for other inflammatory diseases and in particular, cancer therapy. Numerous studies have evaluated the efficacy and potential of nanomedical approaches to modulate these signaling pathways and have been met with positive results. A treatment regime, that includes nanotherapeutics and antiviral therapies will prove effective and holds great promise for the successful treatment of COVID-19. In this article, we review different nanomedical approaches already studied for targeting aberrant signaling pathways, the host immune response to SARS-CoV-2, immunopathology and the dysregulated signaling pathways observed in severe COVID-19 and the current treatment methods in use for targeting signaling cascades in COVID-19. We then conclude by suggesting that the use of nanomedical drug delivery systems for targeting signaling pathways can be extended to effectively target the aberrant signaling pathways in COVID-19 for best treatment results.

Extreme phenotypes approach to investigate host genetics and COVID-19 outcomes

COVID-19 comprises clinical outcomes of SARS-CoV-2 infection and is highly heterogeneous, ranging from asymptomatic individuals to deceased young adults without comorbidities. There is growing evidence that host genetics play an important role in COVID-19 severity, including inborn errors of immunity, age-related inflammation and immunosenescence. Here we present a brief review on the known order of events from infection to severe system-wide disturbance due to COVID-19 and summarize potential candidate genes and pathways. Finally, we propose a strategy of subject's ascertainment based on phenotypic extremes to take part in genomic studies and elucidate intrinsic risk factors involved in COVID-19 severe outcomes.

Early changes in laboratory parameters are predictors of mortality and ICU admission in patients with COVID-19: a systematic review and meta-analysis

Despite the growing knowledge of the clinicopathological features of COVID-19, the correlation between early changes in the laboratory parameters and the clinical outcomes of patients is not entirely understood. In this study, we aimed to assess the prognostic value of early laboratory parameters in COVID-19. We conducted a systematic review and meta-analysis based on the available literature in five databases. The last search was on July 26, 2020, with key terms related to COVID-19. Eligible studies contained original data of at least ten infected patients and reported on baseline laboratory parameters of patients. We calculated weighted mean differences (WMDs) for continuous outcomes and odds ratios (ORs) with 95% confidence intervals. 93 and 78 studies were included in quantitative and qualitative syntheses, respectively. Higher baseline total white blood cell count (WBC), C-reactive protein (CRP), lactate-dehydrogenase (LDH), creatine kinase (CK), D-dimer and lower absolute lymphocyte count (ALC) (WMDALC = - 0.35 × 109/L [CI - 0.43, - 0.27], p < 0.001, I2 = 94.2%; < 0.8 × 109/L, ORALC = 3.74 [CI 1.77, 7.92], p = 0.001, I2 = 65.5%) were all associated with higher mortality rate. On admission WBC, ALC, D-dimer, CRP, LDH, and CK changes could serve as alarming prognostic factors. The correct interpretation of laboratory abnormalities can guide therapeutic decisions, especially in early identification of potentially critical cases. This meta-analysis should help to allocate resources and save lives by enabling timely intervention.

Polysaccharides obtained from natural edible sources and their role in modulating the immune system: Biologically active potential that can be exploited against COVID-19

BACKGROUND

The global crisis caused by the outbreak of severe acute respiratory syndrome caused by the SARS-CoV-2 virus, better known as COVID-19, brought the need to improve the population's immunity. The foods rich in polysaccharides with immunomodulation properties are among the most highly rated to be used as immune response modulators. Thus, the use of polysaccharides obtained from food offers an innovative strategy to prevent serious side effects of viral infections.

SCOPE AND APPROACH

This review revisits the current studies on the pathophysiology of SARS-CoV-2, its characteristics, target cell interactions, and the possibility of using polysaccharides from functional foods as activators of the immune response. Several natural foods are explored for the possibility of being used to obtain polysaccharides with immunomodulatory potential. And finally, we address expectations for the use of polysaccharides in the development of potential therapies and vaccines.

KEY FINDINGS AND CONCLUSIONS

The negative consequences of the SARS-CoV-2 pandemic across the world are unprecedented, thousands of lives lost, increasing inequalities, and incalculable economic losses. On the other hand, great scientific advances have been made regarding the understanding of the disease and forms of treatment. Polysaccharides, due to their characteristics, have the potential to be used as potential drugs with the ability to modulate the immune response. In addition, they can be used safely, as they have no toxic effects, are biocompatible and biodegradable. Finally, these biopolymers can still be used in the development of new therapies and vaccines.

Calming the Storm: Natural Immunosuppressants as Adjuvants to Target the Cytokine Storm in COVID-19

The COVID-19 pandemic has caused a global health crisis, with no specific antiviral to treat the infection and the absence of a suitable vaccine to prevent it. While some individuals contracting the SARS-CoV-2 infection exhibit a well coordinated immune response and recover, others display a dysfunctional immune response leading to serious complications including ARDS, sepsis, MOF; associated with morbidity and mortality. Studies revealed that in patients with a dysfunctional immune response, there is a massive cytokine and chemokine release, referred to as the ‘cytokine storm’. As a result, such patients exhibit higher levels of pro-inflammatory/modulatory cytokines and chemokines like TNFα, INFγ, IL-1β, IL-2, IL-4, IL-6, IL-7, IL-9, IL-10, IL-12, IL-13, IL-17, G-CSF, GM-CSF, MCSF, HGF and chemokines CXCL8, MCP1, IP10, MIP1α and MIP1β. Targeting this cytokine storm is a novel, promising treatment strategy to alleviate this excess influx of cytokines observed at the site of infection and their subsequent disastrous consequences. Natural immunosuppressant compounds, derived from plant sources like curcumin, luteolin, piperine, resveratrol are known to inhibit the production and release of pro-inflammatory cytokines and chemokines. This inhibitory effect is mediated by altering signal pathways like NF-κB, JAK/STAT, MAPK/ERK that are involved in the production and release of cytokines and chemokines. The use of these natural immunosuppressants as adjuvants to ameliorate the cytokine storm; in combination with antiviral agents and other treatment drugs currently in use presents a novel, synergistic approach for the treatment and effective cure of COVID-19. This review briefly describes the immunopathogenesis of the cytokine storm observed in SARS-CoV-2 infection and details some natural immunosuppressants that can be used as adjuvants in treating COVID-19 disease.

Peripheral Inflammatory Cytokines and Lymphocyte Subset Features of Deceased COVID-19 Patients

OBJECTIVE

To compare the difference of inflammatory cytokines and lymphocyte subsets between deceased patients and survivors with COVID-19.

METHODS

This retrospective study included 254 confirmed patients from 10 January to 11 March, 2020, at Tongji Hospital of Wuhan, China. Laboratory and immunologic features were collected and analyzed, and the main outcomes focused on inflammatory cytokines and lymphocyte subsets.

RESULTS

A trend of markedly higher levels of inflammatory cytokines as well as lower lymphocyte subset levels in deceased patients was observed compared with survivors. ROC curve analyses indicated that inflammatory cytokines and the decrease levels of T cell, Th (helper T cells) cell, Ts (suppressor T cells) cell, B cell, and NK cell along with Th/Ts ratio increase could be used to predict the death of COVID-19. Multivariate analyses showed that higher levels of IL-6, IL-8, and IL-10 remained significantly correlated with shorter survival time and that the amount of Ts cells was negatively associated with the possibility of death in COVID-19 patients. In conclusion, SARS-CoV-2 would cause lymphopenia and result in decreased lymphocyte subset cells, particularly in Ts cell counts, which further induces hyperinflammatory response and cytokine storm. IL-6, IL-8, IL-10, and Ts cell might be independent predictors for the poor outcome of COVID-19.

[Cardiovascular diseases and COVID-19 : Pathophysiology, complications and treatment]

COVID-19 („coronavirus disease 2019“) ist eine Herausforderung für unser Gesundheitssystem und gleichzeitig eine der herausragenden Katalysatoren erfolgreicher translationaler Forschung. COVID-19 ist nicht nur eine simple Viruserkrankung des Bronchialsystems, sondern eine pandemisch auftretende, hyperinflammatorische Multiorganerkrankung. Das Herz-Kreislauf-System spielt dabei eine kausale Rolle, da SARS-CoV‑2 („severe acute respiratory syndrome coronavirus 2“) Wirtszellen über ACE(„angiotensin-converting enzyme“)-2, ein Enzym des Renin-Angiotensin-Systems, befällt. Darüber hinaus spielen kardiovaskuläre Komorbiditäten und Risikofaktoren wie Bluthochdruck, Diabetes und Adipositas eine wichtige Rolle für die Schwere der Krankheitsverläufe. Zusätzliche Risikofaktoren wie Geschlecht, Alter, Genetik und Luftverschmutzung modulieren sowohl die Schwere der SARS-CoV-2-Infektion als auch kardiovaskuläre Erkrankungen. Als Folge von COVID-19 kommt es zu vermehrten Thrombosen, Herzinfarkten, Herzmuskelentzündungen und Vaskulitiden, die das kardiovaskuläre System direkt schädigen und wesentlich zur Morbidität und Mortalität beitragen. Erkenntnisse aus zahlreichen Studien zu Krankheitsverläufen von SARS-CoV-2-infizierten Patienten haben zu besseren Therapiemöglichkeiten geführt, die nun in der zweiten Welle zum Teil standardisiert und insbesondere auch an Komplikationen des kardiovaskulären Systems angepasst wurden und werden. In diesem Review geben wir einen kurzen Überblick über die Pathophysiologie des SARS-CoV-2-Virus allgemein sowie auch spezifisch auf das kardiovaskuläre System. Daraus folgend, fassen wir die aktuellen Therapieansätze und deren pathophysiologische Grundlagen (Stand November 2020) zusammen.

Prognostic value of liver biochemical parameters for COVID-19 mortality

INTRODUCTION

Coronavirus disease 2019 (COVID-19) has brought great challenges to global public health. However, a comprehensive analysis of the relationship between liver biochemical parameters and COVID-19 mortality is quite limited.

METHODS

We searched the following electronic databases: PubMed, Embase, Cochrane Library, Web of Science, Scopus, Wanfang and China National Knowledge Infrastructure database until May 5, 2020. STATA software was used for the statistical analyses.

RESULTS

A total of 25 studies involving 5971 COVID-19 patients were included in our analysis. Compared with non-survivors, survivors had lower levels of aspartate aminotransferase (AST) (weighted mean difference [WMD]=-16.71U/L, 95%CI=[-21.03,-12.40], P<0.001), alanine transaminase (ALT) (WMD=-5.20U/L, 95%CI=[-8.00,-2.41], P<0.001), total bilirubin (TBIL) (WMD=4.40μmol/L, 95%CI=[-5.11,-3.70], P<0.001) and lactic dehydrogenase (LDH) (WMD=-252.44U/L, 95%CI=[-289.57,-215.30], P<0.001), and higher albumin (ALB) level (WMD=4.47g/L, 95%CI=[3.47,5.47], P<0.001). Besides, survivors had lower proportions of these abnormally increased parameters (AST: OR=0.25, 95%CI=[0.15,0.41], P<0.001; ALT: OR=0.49, 95%CI=[0.37,0.64], P<0.001; TBIL: (OR=0.20, 95%CI=[0.12,0.34], P<0.001; LDH, OR=0.09, 95%CI=[0.06,0.14], P<0.001), and lower proportion of abnormally decreased ALB (OR=0.16, 95%CI=[0.07,0.38], P<0.001). Meta-analysis based on standard mean difference and sensitivity analysis did not change the conclusions. Egger test did not detect the presence of publication bias.

CONCLUSIONS

Liver biochemical parameters were strongly correlated with COVID-19 mortality. Measurement of these liver biochemical parameters might assist clinicians to evaluate the prognosis of COVID-19.

Peripheral Blood Immune Profiling of Convalescent Plasma Donors Reveals Alterations in Specific Immune Subpopulations Even at 2 Months Post SARS-CoV-2 Infection

Immune profiling of patients with COVID-19 has shown that SARS-CoV-2 causes severe lymphocyte deficiencies (e.g., lymphopenia, decreased numbers, and exhaustion of T cells) and increased levels of pro-inflammatory monocytes. Peripheral blood (PB) samples from convalescent plasma (CP) donors, COVID-19 patients, and control subjects were analyzed by multiparametric flow cytometry, allowing the identification of a wide panel of immune cells, comprising lymphocytes (T, B, natural killer (NK) and NKT cells), monocytes, granulocytes, and their subsets. Compared to active COVID-19 patients, our results revealed that the immune profile of recovered donors was restored for most subpopulations. Nevertheless, even 2 months after recovery, CP donors still had reduced levels of CD4+ T and B cells, as well as granulocytes. CP donors with non-detectable levels of anti-SARS-CoV-2-specific antibodies in their serum were characterized by higher Th9 and Th17 cells, which were possibly expanded at the expense of Th2 humoral immunity. The most noticeable alterations were identified in previously hospitalized CP donors, who presented the lowest levels of CD8+ regulatory T cells, the highest levels of CD56+CD16- NKT cells, and a promotion of a Th17-type phenotype, which might be associated with a prolonged pro-inflammatory response. A longer follow-up of CP donors will eventually reveal the time needed for full recovery of their immune system competence.

Systemic Inflammatory Response Syndrome After Surgery: Mechanisms and Protection

The immune system is an evolutionary hallmark of higher organisms that defends the host against invading pathogens and exogenous infections. This defense includes the recruitment of immune cells to the site of infection and the initiation of an inflammatory response to contain and eliminate pathogens. However, an inflammatory response may also be triggered by noninfectious stimuli such as major surgery, and, in case of an overshooting, still not comprehensively understood reaction, lead to tissue destruction and organ dysfunction. Unfortunately, in some cases, the immune system may not effectively distinguish between stimuli elicited by major surgery, which ideally should only require a modest inflammatory response, and those elicited by trauma or pathogenic infection. Surgical procedures thus represent a potential trigger for systemic inflammation that causes the secretion of proinflammatory cytokines, endothelial dysfunction, glycocalyx damage, activation of neutrophils, and ultimately tissue and multisystem organ destruction. In this review, we discuss and summarize currently available mechanistic knowledge on surgery-associated systemic inflammation, demarcation toward other inflammatory complications, and possible therapeutic options. These options depend on uncovering the underlying mechanisms and could include pharmacologic agents, remote ischemic preconditioning protocols, cytokine blockade or clearance, and optimization of surgical procedures, anesthetic regimens, and perioperative inflammatory diagnostic assessment. Currently, a large gap between basic science and clinically confirmed data exists due to a limited evidence base of translational studies. We thus summarize important steps toward the understanding of the precise time- and space-regulated processes in systemic perioperative inflammation.

Host-pathogen interaction in COVID-19: Pathogenesis, potential therapeutics and vaccination strategies

The current coronavirus pandemic, COVID-19, is the third outbreak of disease caused by the coronavirus family, after Severe Acute Respiratory Syndrome and Middle East Respiratory Syndrome. It is an acute infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This severe disease is characterised by acute respiratory distress syndrome, septic shock, metabolic acidosis, coagulation dysfunction, and multiple organ dysfunction syndromes. Currently, no drugs or vaccines exist against the disease and the only course of treatment is symptom management involving mechanical ventilation, immune suppressants, and repurposed drugs. The severe form of the disease has a relatively high mortality rate. The last six months have seen an explosion of information related to the host receptors, virus transmission, virus structure-function relationships, pathophysiology, co-morbidities, immune response, treatment and the most promising vaccines. This review takes a critically comprehensive look at various aspects of the host-pathogen interaction in COVID-19. We examine the genomic aspects of SARS-CoV-2, modulation of innate and adaptive immunity, complement-triggered microangiopathy, and host transmission modalities. We also examine its pathophysiological impact during pregnancy, in addition to emphasizing various gaps in our knowledge. The lessons learnt from various clinical trials involving repurposed drugs have been summarised. We also highlight the rationale and likely success of the most promising vaccine candidates.

Angiotensin-converting enzyme 2: A protective factor in regulating disease virulence of SARS-COV-2

Novel SARS-CoV-2 named due to its close homology with severe acute respiratory syndrome coronavirus (SARS-CoV) is the etiologic agent for the ongoing pandemic outbreak causing loss of life and severe economic burden globally. The virus is believed to be evolved in a recombined form of bat and animal coronavirus with the capacity to infect human host using the ACE2 receptors as an entry point. Though the disease pathogenesis is not elucidated completely, the virus-mediated host response retains a similar pattern to that of previous SARS-CoV. Based on the available trend it is assumed that pediatric groups are less susceptible to the coronavirus. Understanding the possible mechanism that protects the children from hyper-inflammatory or disease severity could lead to better treatment modalities. In the present review, we have discussed the significance of age and sex-dependent pattern of ACE2 receptor expression and ACE2 variants in the immune protective mechanism of the disease virulence. We have also added a brief note on the importance of sex hormones in the pathogenesis of ACE2 mediated SARS-CoV2 infection.

A systematic review and meta-analysis: the effect of active cancer treatment on severity of COVID-19

Background

The COVID-19 pandemic hit all over the world, and cancer patients are more vulnerable for COVID-19. The mortality rate may increase up to 25% in solid malignancies. In parallel to increased mortality rates among cancer patients, safety concerns regarding cancer treatment has increased over time. However, there were contradictory results for the cancer treatment during pandemic. In this study, we assessed the effect of cancer treatment on the severity of COVID-19.

Methods

The MEDLINE database was searched on September 01, 2020. Primary end-points were severe disease and death in the cancer patients treated within the last 30 days before COVID-19 diagnosis. Quality of included studies was assessed by Newcastle–Ottawa scale. The generic inverse-variance method was used to calculate odds ratios (ORs) for each outcome.

Results

Sixteen studies were included for this meta-analysis. Chemotherapy within the last thirty days before COVID-19 diagnosis increased the risk of death in cancer patients after adjusting for confounding variables (OR: 1.85; 95% confidence interval: 1.26–2.71). However, severe COVID-19 risk did not increase. Furthermore, targeted therapies, immunotherapy, surgery and radiotherapy did not increase the severe disease and death risk in cancer patients with COVID-19.

Conclusion

Chemotherapy increased the risk of death from COVID-19 in cancer patients. However, there was no safety concern for immunotherapy, targeted therapies, surgery and radiotherapy.

Pathophysiology and potential future therapeutic targets using preclinical models of COVID-19

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) gains entry into the lung epithelial cells by binding to the surface protein angiotensin-converting enzyme 2. Severe SARS-CoV-2 infection, also known as coronavirus disease 2019 (COVID-19), can lead to death due to acute respiratory distress syndrome mediated by inflammatory immune cells and cytokines. In this review, we discuss the molecular and biochemical bases of the interaction between SARS-CoV-2 and human cells, and in doing so we highlight knowledge gaps currently precluding development of new effective therapies. In particular, discovery of novel treatment targets in COVID-19 will start from understanding pathologic changes based on a large number of autopsy lung tissue samples. Pathogenetic roles of potential molecular targets identified in human lung tissues must be validated in established animal models. Overall, this stepwise approach will enable appropriate selection of candidate therapeutic modalities targeting SARS-CoV2 and the host inflammatory response.

Complex Immunometabolic Profiling Reveals the Activation of Cellular Immunity and Biliary Lesions in Patients with Severe COVID-19

This study aimed to assess the key laboratory features displayed by coronavirus disease 2019 (COVID-19) inpatients that are associated with mild, moderate, severe, and fatal courses of the disease, and through a longitudinal follow-up, to understand the dynamics of the COVID-19 pathophysiology. All severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive patients admitted to the University Hospital in Motol between March and June 2020 were included in this study. A severe course of COVID-19 was associated with an elevation of proinflammatory markers; an efflux of immature granulocytes into peripheral blood; the activation of CD8 T cells, which infiltrated the lungs; transient liver disease. In particular, the elevation of serum gamma-glutamyl transferase (GGT) and histological signs of cholestasis were highly specific for patients with a severe form of the disease. In contrast, patients with a fatal course of COVID-19 failed to upregulate markers of inflammation, showed discoordination of the immune response, and progressed toward acute kidney failure. COVID-19 is a disease with a multi-organ affinity that is characterized by the activation of innate and cellular adaptive immunity. Biliary lesions with an elevation of GGT and the organ infiltration of interleukin 6 (IL-6)-producing cells are the defining characteristics for patients with the fulminant disease.

Natural Killer Cell Dysfunction and Its Role in COVID-19

When facing an acute viral infection, our immune systems need to function with finite precision to enable the elimination of the pathogen, whilst protecting our bodies from immune-related damage. In many instances however this "perfect balance" is not achieved, factors such as ageing, cancer, autoimmunity and cardiovascular disease all skew the immune response which is then further distorted by viral infection. In SARS-CoV-2, although the vast majority of COVID-19 cases are mild, as of 24 August 2020, over 800,000 people have died, many from the severe inflammatory cytokine release resulting in extreme clinical manifestations such as acute respiratory distress syndrome (ARDS) and hemophagocytic lymphohistiocytosis (HLH). Severe complications are more common in elderly patients and patients with cardiovascular diseases. Natural killer (NK) cells play a critical role in modulating the immune response and in both of these patient groups, NK cell effector functions are blunted. Preliminary studies in COVID-19 patients with severe disease suggests a reduction in NK cell number and function, resulting in decreased clearance of infected and activated cells, and unchecked elevation of tissue-damaging inflammation markers. SARS-CoV-2 infection skews the immune response towards an overwhelmingly inflammatory phenotype. Restoration of NK cell effector functions has the potential to correct the delicate immune balance required to effectively overcome SARS-CoV-2 infection.