SARS-CoV-2: A comprehensive review from pathogenicity of the virus to clinical consequences

Impacts of Inflammatory Cytokines Variants on Systemic Inflammatory Profile and COVID-19 Severity

BACKGROUND

Cytokine storm is known to impact the prognosis of coronavirus disease 2019 (COVID-19), since pro-inflammatory cytokine variants are associated with cytokine storm. It is tempting to speculate that pro-inflammatory cytokines variants may impact COVID-19 outcomes by modulating cytokine storm. Here, we verified this hypothesis via a comprehensive analysis.

METHODS

PubMed, Cochrane Library, Central, CINAHL, and ClinicalTrials.gov were searched until December 15, 2023. Case-control or cohort studies that investigated the impacts of rs1800795 or rs1800629 on COVID-19 susceptibility, severity, mortality, IL-6, TNF-α, or CRP levels were included after an anonymous review by two independent reviewers and consultations of disagreement by a third independent reviewer.

RESULTS

47 studies (8305 COVID-19 individuals and 17,846 non-COVID-19 individuals) were analyzed. The rs1800629 A allele (adenine at the -308 position of the promoter was encoded by the A allele) was associated with higher levels of tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP). In contrast, the rs1800795 C allele (cytosine at the -174 position of the promoter was encoded by the C allele) was linked to higher levels of interleukin-6 (IL-6) and CRP. In addition, the A allele of rs1800629 increased the severity and mortality of COVID-19. However, the C allele of rs1800795 only increased COVID-19 susceptibility.

CONCLUSIONS

rs1800629 and rs1800795 variants of pro-inflammatory cytokines have significant impacts on systemic inflammatory profile and COVID-19 clinical outcomes. rs1800629 may serve as a genetic marker for severe COVID-19.

Immunomodulatory effects of cannabinoids against viral infections: a review of its potential use in SARS-CoV2 infection

The COVID-19 pandemic is a global health crisis affecting millions of people worldwide. Along with vaccine development, there is also a priority to discover new drugs and treatments. One approach involves modulating the immune system to manage inflammation and cytokine storms. Patients with a high severity of complications exhibit a high level of inflammatory cytokines, particularly IL-6, in the airways and other infected tissues. Several studies have reported the function of the endocannabinoid system in regulating inflammation and different immune responses. Cannabinoids are a class of natural chemicals found in the Cannabis plant. Recently, the anti-inflammatory properties of cannabinoids and their mediatory immunosuppression mechanisms through the endocannabinoid system have engrossed scientists in the health field for infectious conditions. Research suggests that the immune system can regulate cytokine activation through cannabinoid receptors, particularly with Cannabidiol (CBD), the second most prevalent compound in cannabis. While CBD has been deemed safe by the World Health Organization and shows no signs of abuse potential, excessive CBD use may lead to respiratory depression. CBD shows promise in reducing immune cell recruitment and cytokine storms in organs affected by SARS-CoV2. However, before clinical use, it's crucial to evaluate cannabinoid-based medications' active ingredient concentrations and potential interactions with other drugs, along with associated side effects. Indication-based dosing, consistent formulations, and ensuring purity and potency are essential. This review highlights cannabinoids' effects on COVID-19 management and prognosis, drawing from preclinical and clinical studies.

Exploring immune evasion of SARS-CoV-2 variants using a pseudotyped system

In the United States, coronavirus disease 2019 (COVID-19) cases have consistently been linked to the prevailing variant XBB.1.5 of SARS-CoV-2 since late 2022. A system has been developed for producing and infecting cells with a pseudovirus (PsV) of SARS-CoV-2 to investigate the infection in a Biosafety Level 2 (BSL-2) laboratory. This system utilizes a lentiviral vector carrying ZsGreen1 and Firefly luciferase (Fluc) dual reporter genes, facilitating the analysis of experimental results. In addition, we have created a panel of PsV variants that depict both previous and presently circulating mutations found in circulating SARS-CoV-2 strains. A series of PsVs includes the prototype SARS-CoV-2, Delta B.1.617.2, BA.5, XBB.1, and XBB.1.5. To facilitate the study of infections caused by different variants of SARS-CoV-2 PsV, we have developed a HEK-293T cell line expressing mCherry and human angiotensin converting enzyme 2 (ACE2). To validate whether different SARS-CoV-2 PsV variants can be used for neutralization assays, we employed serum from rats immunized with the PF-D-Trimer protein vaccine to investigate its inhibitory effect on the infectivity of various SARS-CoV-2 PsV variants. According to our observations, the XBB variant, particularly XBB.1.5, exhibits stronger immune evasion capabilities than the prototype SARS-CoV-2, Delta B.1.617.2, and BA.5 PsV variants. Hence, utilizing the neutralization test, this study has the capability to forecast the effectiveness in preventing future SARS-CoV-2 variants infections.

Microfluidics-Based Nanobiosensors for Healthcare Monitoring

Efficient healthcare management demands prompt decision-making based on fast diagnostics tools, astute data analysis, and informatics analysis. The rapid detection of analytes at the point of care is ensured using microfluidics in synergy with nanotechnology and biotechnology. The nanobiosensors use nanotechnology for testing, rapid disease diagnosis, monitoring, and management. In essence, nanobiosensors detect biomolecules through bioreceptors by modulating the physicochemical signals generating an optical and electrical signal as an outcome of the binding of a biomolecule with the help of a transducer. The nanobiosensors are sensitive and selective and play a significant role in the early identification of diseases. This article reviews the detection method used with the microfluidics platform for nanobiosensors and illustrates the benefits of combining microfluidics and nanobiosensing techniques by various examples. The fundamental aspects, and their application are discussed to illustrate the advancement in the development of microfluidics-based nanobiosensors and the current trends of these nano-sized sensors for point-of-care diagnosis of various diseases and their function in healthcare monitoring.

Synthesis and studies of new purines/pyrimidine derivatives as multi-targeted agents involving various receptor sites in the immune system

Pro-inflammation, which is developed due to the increased production of cytokines, mainly interleukin-6 (IL-6), during the working of immune system pathways, becomes a major concern these days for many researchers. So, it is desired to design, screen, and synthesize new molecules with multi-parametric features showing their efficacy for Toll-like receptors (TLRs) and inhibiting the disease-causing receptor sites like viral infections, cancers, etc. along with controlling inflammation, fever, and other side effects during such pathways. Further, looking at the literature, curcumin a multi-targeted agent is showing its efficiency toward various receptor sites involved in many diseases as mentioned above. This fascinated us to build up new molecules which behave like curcumin with minimum side effects. In silico studies, involving ADMET studies, toxicological data, and docking analyses, of newly synthesized compounds (3-5) along with tautomers of curcumin i.e., (1-2), and some reported compounds like 9 and 10 have been studied in detail. Great emphasis has been made on analyzing binding energies, protein-ligand structural interactions, stabilization of newly synthesized molecules against various selected receptor sites using such computational tools. Compound 3 is the most efficient multifunctional agent, which has shown its potential toward most of the receptor sites in docking analysis. It has also responded well in Molecular dynamics (MD) simulation toward 5ZLN, 4RJ3, 4YO9, 4YOJ, and 1I1R sites. Finally, studies were extended to understand in vitro anti-inflammatory activity for particularly compound 3 in comparison to diclofenac and curcumin, which signifies the efficiency of compound 3.

Clinical Trials of Mesenchymal Stem Cells for the Treatment of COVID 19

Mesenchymal Stem Cells (MSCs) are being investigated as a treatment for a novel viral disease owing to their immunomodulatory, anti-inflammatory, tissue repair and regeneration characteristics, however, the exact processes are unknown. MSC therapy was found to be effective in lowering immune system overactivation and increasing endogenous healing after SARS-CoV-2 infection by improving the pulmonary microenvironment. Many studies on mesenchymal stem cells have been undertaken concurrently, and we may help speed up the effectiveness of these studies by collecting and statistically analyzing data from them. Based on clinical trial information found on clinicaltrials. gov and on 16 November 2020, which includes 63 clinical trials in the field of patient treatment with COVID-19 using MSCs, according to the trend of increasing studies in this field, and with the help of meta-analysis studies, it is possible to hope that the promise of MSCs will one day be realized. The potential therapeutic applications of MSCs for COVID-19 are investigated in this study.

SARS-CoV-2 excretion kinetics in nasopharyngeal and stool samples from the pediatric population

Background

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for serious respiratory infections in humans. Even in the absence of respiratory symptoms, gastrointestinal (GI) signs were commonly reported in adults and children. Thus, oral-fecal transmission was suspected as a possible route of infection. The objective of this study was to describe RNA shedding in nasopharyngeal and stool samples obtained from asymptomatic and symptomatic children and to investigate virus viability.

Methods

This study included 179 stool and 191 nasopharyngeal samples obtained from 71 children, which included symptomatic (n = 64) and asymptomatic (n = 7) ones. They were collected every 7 days from the onset of the infection until negativation. Viral RNA was detected by real-time RT-PCR, targeting the N and ORF1 genes. Whole-genome sequencing was performed for positive cases. Viral isolation was assessed on Vero cells, followed by molecular detection confirmation.

Results

All cases included in this study (n = 71) were positive in their nasopharyngeal samples. SARS-CoV-2 RNA was detected in 36 stool samples obtained from 15 out of 71 (21.1%) children; 13 were symptomatic and two were asymptomatic. Excretion periods varied from 7 to 21 days and 7 to 14 days in nasopharyngeal and fecal samples, respectively. Four variants were detected: Alpha (n = 3), B.1.160 (n = 3), Delta (n = 7), and Omicron (n = 1). Inoculation of stool samples on cell culture showed no specific cytopathic effect. All cell culture supernatants were negative for RT-qPCR.

Conclusion

Our study demonstrated nasopharyngeal and fecal shedding of SARS-CoV-2 RNA by children up to 21 and 14 days, respectively. Fecal shedding was recorded in symptomatic and asymptomatic children. Nevertheless, SARS-CoV-2 was not isolated from positive stool samples.

Lack of Evidence for a Role of ACE-2 Polymorphisms as a Bedside Clinical Prognostic Marker of COVID-19

The novel SARS-CoV-2 coronavirus causes a severe respiratory syndrome referred to as coronavirus disease (COVID-19). The angiotensin-converting enzyme 2 (ACE-2) plays an important role as a cellular receptor for SARS-CoV-2 and is largely expressed in lungs, kidneys, heart and the gastrointestinal tract along with being shed in plasma. The ACE-2 gene and protein show a high level of genetic polymorphism, including simple nucleotide variation, transcriptional variation, post-transcriptional changes, and putative protein mutations that could interfere with the binding or entry of SARS-CoV-2 and affect tissue damage in lungs or other organs. Genetic polymorphisms can impact SARS-CoV-2 viral entry and COVID-19 severity. This single-center study evaluated the possible role of the main ACE-2 polymorphisms (rs143936283, rs2285666, rs41303171, rs35803318, and rs2106809) as potential prognostic markers in SARS-CoV-2-infected individuals. Frozen whole blood was used for DNA isolation and genomic DNA samples were sheared using the Covaris LE220 Focused-ultrasonicator for targeting a peak size of 410 bp. Whole-genome sequencing libraries were generated from fragmented DNA using the Illumina TruSeq DNA PCR-Free HT Library Preparation Kit and sequenced on an Illumina NovaSeq 6000. We did not identify any correlation between ACE-2 polymorphisms and COVID-19 prognosis, suggesting that the interpretation and clinical use of ACE-2 genetic polymorphisms in real-world clinical settings requires further experimental and clinical validation.

The investigation of host genetic variants of toll-like receptor 7 and 8 in COVID-19

Toll-like receptors (TLRs) recognize infectious agents and play an important role in the innate immune system. Studies have suggested that TLR single nucleotide polymorphisms (SNPs) are associated with poor antiviral responses against SARS-CoV-2. Therefore, we aimed to investigate the relationship of TLR7 and TLR8 (SNPs) with COVID-19 disease prognosis. A total of 120 COVID-19 patients, 40 outpatients, 40 clinical ward patients and 40 intensive care unit (ICU) patients were included in the study. TLR7 (rs179009), TLR8-129 C/G (rs3764879) and TLR8 Met1Val (rs3764880) SNPs were genotyped using the PCR-RFLP method. In female patients, individuals carrying AG genotype and G allele for TLR8 Met1Val SNP were found at a higher frequency in patients hospitalized in the ICU than in patients followed in the clinical ward (p < 0.05). In terms of the other two SNPs, no significant difference was found between the groups in females. Furthermore, in male patients, A allele of TLR7 rs179009 SNP was at a higher frequency in patients who have at least one comorbidity than in patients who have no comorbidity (p < 0.05). Our results suggest that TLR8 Met1Val SNP is important in the COVID-19 disease severity in females. Furthermore, TLR7 rs179009 SNP is important in male patients in the presence of comorbid diseases.

Using a novel two-stage strategy to characterize the spatial distribution of associations between temperature and COVID-19: A case study in the continental United States

BACKGROUND

Numerous studies have studied the association between daily average temperature (DAT) and daily COVID-19 confirmed cases, which show considerable heterogeneity, even opposite results, among different regions. Such heterogeneity suggests that characterizing the association on a large area scale would ignore the local variation, even obtain false results in some local regions. So, characterizing the spatial distribution of heterogeneous DAT-COVID-19 associations and exploring the causes plays an important role on making temperature-related region-specific intervention measures and early-warning systems.

METHODS

Aiming to characterize the spatial distribution of associations between DAT and COVID-19 confirmed cases in the continental United States, we proposed a novel two-stage strategy. In the first stage, we used the common stratified distributed lag nonlinear model to obtain the rough state-specific associations. In the second stage, conditional autoregression was used to spatially smooth the rough estimations. Furtherly, based on the idea, two modified strategies were used to investigate the time-varying associations and the modification effects derived from the vaccination campaign.

RESULTS

Around one-third of states exhibit no significant association between DAT and daily confirmed COVID-19 cases. Most of the remaining states present a low risk at low DAT and a high risk at high DAT, but several states present opposite associations. The average association curve presents a 'S' shape with positive association between -8 - 18 °C and keeping flat out of the range. An increased vaccination coverage rate will increase the risk when DAT < 12 °C, but slightly affect the risk when DAT > 12 °C.

CONCLUSION

A considerable spatial heterogeneity of DAT-COVID-19 associations exists in America and the average association curve presents a 'S' shape. The vaccination campaign significantly modifies the association when DAT is low, but only make a slight modification when DAT is high.

Antibody Therapy for COVID-19: Categories, Pros, and Cons

COVID-19 is a life-threatening respiratory disease triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has been considered a pandemic viral infection since December 2019. The investigation of the effective prophylaxis or therapeutic strategies for emergency management of the current condition has become a priority for medical research centers and pharmaceutical companies. This article provides a comprehensive review of antibody therapy and its different categories with their advantages and disadvantages for COVID-19 over the last few years of the current pandemic. Antibodies can be generated by active immunization, including natural infection with a pathogen and vaccination, or by the passive immunization method such as convalescent plasma therapy (CPT) and antibody synthesis in laboratories. Each of these ways has its characteristics. Arming the immune system with antibodies is the main aim of antiviral therapeutic procedures toward SARS-CoV-2. Collecting and discussing various aspects of available data in this field can give researchers a better perspective for the production of antibody-based products or selection of the most appropriate approach of antibody therapies to improve different cases of COVID-19. Moreover, it can help them control similar viral pandemics that may happen in the future appropriately.

Evaluation of the Costs and Outcomes of COVID-19 Therapeutic Regimens in Hospitalized Patients in Shiraz

COVID-19 patients in critical conditions are hospitalized and treated with various protocols including antiviral drugs, which have been updated repeatedly. This study was aimed to analyze the demographics, costs, and outcomes of drug regimens in COVID-19 patients hospitalized in "Ali Asghar" hospital, affiliated with Shiraz University of Medical Sciences, from March 2019 to December 2020 as a retrospective study, approved by the ethics committee of Shiraz University of Medical Sciences (IR.SUMS.REC.1399.1003) on Dec. 28, 2020. Using hospital information system (HIS) data, 2174 patients receiving favipiravir, remdesivir, interferon-β, and Kaletra^® were analyzed. Descriptive, univariate, and regression analyses were used. The costs and consequences of different drug regimens were significantly different (P value < 0.05); the highest and lowest costs belonged to remdesivir and Kaletra^®, respectively. The highest and lowest mean length of stay and mortality were related to remdesivir and favipiravir, respectively. Mortality did not differ significantly with various regimens. Length of stay was significantly shorter with favipiravir and Kaletra^® than interferon-β. Remdesivir had significantly the highest cost. Age presented a significantly positive relationship with mortality and length of stay. Besides, ICU admission significantly increased mortality, length of stay, and costs. Underlying diseases and low blood oxygen saturation contributed to mortality. COVID-19 correlation with age and underlying diseases is accordant with the published data. Given the highest costs and broad usage of remdesivir, besides controversies regarding its outcomes and side effects, a stricter evaluation of remdesivir benefits seems essential. Totally, COVID-19 therapeutic protocols should be selected carefully to optimize costs and outcomes.

Toll-like Receptor Mediation in SARS-CoV-2: A Therapeutic Approach

The innate immune system facilitates defense mechanisms against pathogen invasion and cell damage. Toll-like receptors (TLRs) assist in the activation of the innate immune system by binding to pathogenic ligands. This leads to the generation of intracellular signaling cascades including the biosynthesis of molecular mediators. TLRs on cell membranes are adept at recognizing viral components. Viruses can modulate the innate immune response with the help of proteins and RNAs that downregulate or upregulate the expression of various TLRs. In the case of COVID-19, molecular modulators such as type 1 interferons interfere with signaling pathways in the host cells, leading to an inflammatory response. Coronaviruses are responsible for an enhanced immune signature of inflammatory chemokines and cytokines. TLRs have been employed as therapeutic agents in viral infections as numerous antiviral Food and Drug Administration-approved drugs are TLR agonists. This review highlights the therapeutic approaches associated with SARS-CoV-2 and the TLRs involved in COVID-19 infection.

SARS-CoV-2 infection in pediatric population before and during the Delta (B.1.617.2) and Omicron (B.1.1.529) variants era

BACKGROUND

COVID-19, the coronavirus disease that emerged in December 2019, caused drastic damage worldwide. At the beginning of the pandemic, available data suggested that the infection occurs more frequently in adults than in infants. In this review, we aim to provide an overview of SARS-CoV-2 infection in children before and after B.1.617.2 Delta and B.1.1.529 Omicron variants emergence in terms of prevalence, transmission dynamics, clinical manifestations, complications and risk factors.

METHODS

Our method is based on the literature search on PubMed, Science Direct and Google Scholar. From January 2020 to July 2022, a total of 229 references, relevant for the purpose of this review, were considered.

RESULTS

The incidence of SARS-CoV-2 infection in infants was underestimated. Up to the first half of May, most of the infected children presented asymptomatic or mild manifestations. The prevalence of COVID-19 varied from country to another: the highest was reported in the United States (22.5%). COVID-19 can progress and become more severe, especially with the presence of underlying health conditions. It can also progress into Kawasaki or Multisystem Inflammatory Syndrome (MIS) manifestations, as a consequence of exacerbating immune response. With the emergence of the B.1.617.2 Delta and B.1.1.529 Omicron variants, it seems that these variants affect a large proportion of the younger population with the appearance of clinical manifestations similar to those presented by adults with important hospitalization rates.

CONCLUSION

The pediatric population constitutes a vulnerable group that requires particular attention, especially with the emergence of more virulent variants. The increase of symptomatic SARS-CoV-2 infection and hospitalization rate among children highlights the need to extend vaccination to the pediatric population.

An Update on the Mutual Impact between SARS-CoV-2 Infection and Gut Microbiota

The gut microbiota is essential for good health. It has also been demonstrated that the gut microbiota can regulate immune responses against respiratory tract infections. Since the outbreak of the COVID-19 pandemic, accumulating evidence suggests that there is a link between the severity of COVID-19 and the alteration of one's gut microbiota. The composition of gut microbiota can be profoundly affected by COVID-19 and vice versa. Here, we summarize the observations of the mutual impact between SARS-CoV-2 infection and gut microbiota composition. We discuss the consequences and mechanisms of the bi-directional interaction. Moreover, we also discuss the immune cross-reactivity between SARS-CoV-2 and commensal bacteria, which represents a previously overlooked connection between COVID-19 and commensal gut bacteria. Finally, we summarize the progress in managing COVID-19 by utilizing microbial interventions.

Prevalence of the Clinical Symptoms and PCR Test Results on Patients With COVID-19 in South of Tehran

Background:

The first human case of COVID-19 was reported on 19 February 2020 in Iran, since then the number of infected cases has dramatically increased to about 1.800 million and about 62 000 deaths, also elderly people have accounted for the largest frequency of mortality.

Objective:

This study aims to evaluate the prevalence of Covid-19 RT-PCR positive among Iranian patients and to evaluate the most important clinical symptoms of identified patients based on age, gender, and their background diseases to be used as an aid for early diagnosis.

Methods:

During 9 months, swab samples of 11 034 patients’ nasopharynx and oropharynx secretions were obtained and were referred to the laboratory for Covid-19 RT-PCR test. In addition, the history of signs and symptoms from patients was recorded.

Results:

In total, 11 034 Covid-19 RT-PCR tests that performed, 3358 samples had positive results (30.4%). Headache was the most commonly reported, which was found in 42.5% of our cases. Fever was the second most common symptom among the patients studied, with a prevalence rate of 36.2%.

Conclusion:

In this study, almost 30% of symptomatic patients had positive Covid-19 RT-PCR test results. Headache was the most common symptom; also diarrhea and nausea were the least common symptoms among patients under this study.

mRNA expression of toll-like receptors 3, 7, 8, and 9 in the nasopharyngeal epithelial cells of coronavirus disease 2019 patients

Background

The etiopathogenesis of coronavirus disease 2019 (COVID-19) stem partially from the abnormal activation of the innate and adaptive immune systems. Here in the current investigation, the mRNA expression levels of toll-like receptors (TLRs) were evaluated in the nasopharyngeal epithelial cells from COVID-19 patients.

Methods

Epithelial cells were obtained using nasopharyngeal swab samples from 90 COVID-19 patients and 50 controls. COVID-19 cases were classified into those without symptoms, with symptoms but not hospitalized, and with symptoms and hospitalized. To determine the mRNA expression levels of TLRs, first RNA was extracted and cDNA was synthesized, and finally Real-time PCR was exerted.

Results

It was seen that the transcript levels of TLR3, TLR7, TLR8, and TLR9 were overexpressed in the COVID-19 patients with clinical symptoms needing hospitalization as well as in those with clinical symptoms without needing for hospitalization compared to controls. Upregulation of TLRs was associated with clinical presentations of the patients.

Conclusions

Modulation of TLR3, TLR7, TLR8, TLR9 in the epithelial cells of COVID-19 cases may estimate the disease severity and requirement for hospitalization.

BCG-Based Vaccines Elicit Antigen-Specific Adaptive and Trained Immunity against SARS-CoV-2 and Andes orthohantavirus

Background:Mycobacterium bovis Bacillus Calmette-Guérin (BCG) is a live attenuated vaccine mainly administered to newborns and used for over 100 years to prevent the disease caused by Mycobacterium tuberculosis (M. tb). This vaccine can induce immune response polarization towards a Th1 profile, which is desired for counteracting M. tb, other mycobacteria, and unrelated intracellular pathogens. The vaccine BCG has been used as a vector to express recombinant proteins and has been shown to protect against several diseases, particularly respiratory viruses. Methods: BCG was used to develop recombinant vaccines expressing either the Nucleoprotein from SARS-CoV-2 or Andes orthohantavirus. Mice were immunized with these vaccines with the aim of evaluating the safety and immunogenicity parameters. Results: Immunization with two doses of 1 × 10⁸ CFU or one dose of 1 × 10⁵ CFU of these BCGs was safe in mice. A statistically significant cellular immune response was induced by both formulations, characterized as the activation of CD4⁺ and CD8⁺ T cells. Stimulation with unrelated antigens resulted in increased expression of activation markers by T cells and secretion of IL-2 and IFN-γ, while increased secretion of IL-6 was found for both recombinant vaccines; all of these parameters related to a trained immunity profile. The humoral immune response elicited by both vaccines was modest, but further exposure to antigens could increase this response. Conclusions: The BCG vaccine is a promising platform for developing vaccines against different pathogens, inducing a marked antigen-specific immune response.

Mesenchymal stromal cell delivery as a potential therapeutic strategy against COVID-19: Promising evidence from in vitro results

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) pandemic, which was initiated in December 2019. COVID-19 is characterized by a low mortality rate (< 6%); however, this percentage is higher in elderly people and patients with underlying disorders. COVID-19 is characterized by mild to severe outcomes. Currently, several therapeutic strategies are evaluated, such as the use of anti-viral drugs, prophylactic treatment, monoclonal antibodies, and vaccination. Advanced cellular therapies are also investigated, thus representing an additional therapeutic tool for clinicians. Mesenchymal stromal cells (MSCs), which are known for their immunoregulatory properties, may halt the induced cytokine release syndrome mediated by SARS-CoV-2, and can be considered as a potential stem cell therapy.

AIM

To evaluate the immunoregulatory properties of MSCs, upon stimulation with COVID-19 patient serum.

METHODS

MSCs derived from the human Wharton’s Jelly (WJ) tissue and bone marrow (BM) were isolated, cryopreserved, expanded, and defined according to the criteria outlined by the International Society for Cellular Therapies. Then, WJ and BM-MSCs were stimulated with a culture medium containing 15% COVID-19 patient serum, 1% penicillin-streptomycin, and 1% L-glutamine for 48 h. The quantification of interleukin (IL)-1 receptor a (Ra), IL-6, IL-10, IL-13, transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF)-a, fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), and indoleamine-2,3-dioxygenase (IDO) was performed using commercial ELISA kits. The expression of HLA-G1, G5, and G7 was evaluated in unstimulated and stimulated WJ and BM-MSCs. Finally, the interactions between MSCs and patients’ macrophages were established using co-culture experiments.

RESULTS

Thawed WJ and BM-MSCs exhibited a spindle-shaped morphology, successfully differentiated to “osteocytes”, “adipocytes”, and “chondrocytes”, and in flow cytometric analysis were characterized by positivity for CD73, CD90, and CD105 (> 95%) and negativity for CD34, CD45, and HLA-DR (< 2%). Moreover, stimulated WJ and BM-MSCs were characterized by increased cytoplasmic granulation, in comparison to unstimulated cells. The HLA-G isoforms (G1, G5, and G7) were successfully expressed by the unstimulated and stimulated WJ-MSCs. On the other hand, only weak expression of HLA-G1 was identified in BM-MSCs. Stimulated MSCs secreted high levels of IL-1Ra, IL-6, IL-10, IL-13, TGF-β1, FGF, VEGF, PDGF, and IDO in comparison to unstimulated cells (P < 0.05) after 12 and 24 h. Finally, macrophages derived from COVID-19 patients successfully adapted the M2 phenotype after co-culturing with stimulated WJ and BM-MSCs.

CONCLUSION

WJ and BM-MSCs successfully produced high levels of immunoregulatory agents, which may efficiently modulate the over-activated immune responses of critically ill COVID-19 patients.

Aortic dissection and Covid-19; a comprehensive systematic review

Coronavirus disease 19 (Covid-19) has been declared as a pandemic disease since March 2020; causing wide array of signs and symptoms, many of which result in increased mortality rates worldwide. Although it was initially known as an acute respiratory disease, Covid-19 is accompanied with several extrapulmonary manifestations, of which the cardiovascular ones are of major importance. Among other cardiovascular complications of Covid-19, aortic dissection has been a significant yet underrated problem. The pathophysiology of aortic dissection consists of various inflammatory pathways, that could be influenced by Covid-19 infection. We herein have reviewed articles inclusive of aortic dissection concurrent with Covid-19 infection in a systematic manner, along with the probable similarities in pathophysiology of aortic dissection with Covid-19 infection.

Comparison of Perinatal, Newborn, and Audiometry Results of COVID-19 Pregnant Women

OBJECTIVE

There are studies on the perinatal outcomes of COVID-19, but the audiometric effects of the maternal immune system against COVID-19 in the newborn are not clear. In this study, we aimed to investigate the relationship between the perinatal outcomes of COVID-19 positive pregnant women and the audiological outcomes of newborns.

MATERIALS AND METHODS

This retrospective, single-center cohort study was conducted with 65 polymerase chain reaction (PCR) positive pregnant women and newborns and 66 normal pregnant women and newborns who were admitted between January 2020-December 2021. Pregnancy data, perinatal outcomes, and newborn hearing test results of pregnant women and newborns were recorded and compared.

RESULTS

A total of 131 patients were enrolled in the study. The number of normal pregnant women was 66 (50.4%) and the number of pregnant women who had COVID-19 disease was 65 (49.6%). In general, gestational week, age, parity, biochemical parameters, duration of hospital stay, week of delivery, fetal weight, and apgar scores were compared between pregnant women with COVID-19 and normal. White blood cell (WBC), neutrophil, aspartate aminotransferase (AST), and C-reactive protein (CRP) parameters were found to be significantly higher, and lymphocyte and neutrophil/lymphocyte (N/L) ratios were significantly lower (p < 0.05). There was no statistically significant difference between the two groups (χ ²=0.001; p = 1,000). The normal delivery status, the normal delivery rate in patients with COVID-19 was found to be statistically significantly higher than the cesarean section delivery status (p = 0.012). In the statistical comparison between the COVID-19 and normal pregnant groups in the cesarean section group, the gestational week, delivery week, and apgar1 scores of the pregnant women with COVID-19 were found to be significantly higher. There was no statistically significant difference between the distributions of the rate of infants with hearing impairment in the comparison with hearing tests in pregnant women with COVID-19 (n=1) and normal pregnant women (n=1) (χ ²=0.001; p = 1,000).

CONCLUSION

Although the negative effects of COVID-19 on pregnancy outcomes are rare, it was determined that there was no increased audiological risk factor, and the most important predictor of COVID-19 was lymphopenia.

Clinical Features and Outcomes of COVID-19 Patients with Acute Kidney Injury and Acute Kidney Injury on Chronic Kidney Disease

COVID-19 emerged in Wuhan in December 2019 and soon became a worldwide pandemic. We collected and analyzed the data from 1077 patients with COVID-19 who were admitted to the west campus of Wuhan Union Hospital from January 16 to April 16, 2020. Sixty (5.6%) of the 1077 COVID-19 patients were diagnosed with acute kidney injury (AKI) during hospitalization, and 18 of them (30%) had AKI on chronic kidney disease (AKI/CKD). COVID-19 patients with AKI had a worse prognosis, with higher intensive care unit (ICU) admission (28.3%) and fatality (65%) rates than patients without AKI (3.4% and 10.7%, respectively). Among the COVID-19 patients, AKI was more likely to occur in male patients, the elderly, patients with more severe disease states and those with comorbidities (such as hypertension, diabetes, coronary heart disease (CHD), chronic obstructive pulmonary disease (COPD) and CKD). COVID-19 patients with AKI were more likely to develop respiratory failure, gastrointestinal bleeding, acute liver injury, acute myocardial injury, heart failure, acute respiratory distress syndrome (ARDS), cerebrovascular accident, and disseminated intravascular coagulation (DIC) than those without AKI. Compared with patients without AKI, COVID-19 patients with AKI had lower platelet counts, lymphocyte counts, albumin levels and serum calcium levels but had elevated leukocyte counts, neutrophil counts and serum potassium levels. Inflammatory indicators, such as C-reactive protein (CRP), interleukin-6 (IL-6), and procalcitonin (PCT), were significantly higher in patients with AKI than in those without AKI. COVID-19 patients with AKI also exhibited a longer prothrombin time (PT), a longer activated partial thromboplastin time (APTT), and a higher D-dimer level than those without AKI. Survival analysis revealed that COVID-19 patients with AKI had a reduced survival rate compared with those without AKI. Furthermore, COVID-19 patients with AKI/CKD had a lower survival rate than those with AKI or CKD only. Multiple logistic regression indicated that the predictors of AKI in COVID-19 patients included complications, such as respiratory failure and acute myocardial injury, and higher creatinine and PCT levels during hospitalization.

Autoimmune complications of COVID-19

Coronavirus disease 2019 (COVID-19) is still propagating a year after the start of the pandemic. Besides the complications patients face during the COVID-19 disease period, there is an accumulating body of evidence concerning the late-onset complications of COVID-19, of which autoimmune manifestations have attracted remarkable attention from the first months of the pandemic. Autoimmune hemolytic anemia, immune thrombocytopenic purpura, autoimmune thyroid diseases, Kawasaki disease, Guillain-Barre syndrome, and the detection of autoantibodies are the cues to the discovery of the potential of COVID-19 in inducing autoimmunity. Clarification of the pathophysiology of COVID-19 injuries to the host, whether it is direct viral injury or autoimmunity, could help to develop appropriate treatment.

Innate and Adaptive Immunity Imbalance With Severe COVID-19 Pneumonia in Children and Adults

Introduction: Little is known about the laboratory and radiological characteristics and clinical significance of peripheral immune alterations in patients with coronavirus disease 2019 (COVID-19). This study aims to clarify these aspects in children and adults with COVID-19. Methods: In this consecutive pilot study, COVID-19 patients with the confirmed pneumonia and real-time RT-PCR were recruited prospectively in June 2020. The clinical, chest CT, and laboratory features, such as lymphocyte subpopulations, were analyzed for each individual. Results: Forty confirmed COVID-19 patients, 11 severe children, 12 severe adults, and 17 critical adult patients, besides 20 healthy pediatrics and 14 healthy adults as controls, were enrolled prospectively. Adult patients, especially critical ones, had a much higher prevalence of laboratory and chest CT abnormalities. Data regarding immune cell subsets in children patients, compared with matched controls, had higher CD3+ CD8+ T cells (p = 0.004) and lower CD4+/CD8+ ratio (p = 0.042), while adult patients, compared with matched controls, had lower CD14+ monocytes (p = 0.032). Adult patients were also categorized as experiencing critical or severe illness on admission and, compared with severe patients, had lower total lymphocytes (p < 0.047), CD3+ T-lymphocytes (p < 0.002), and CD3+ CD8+ T cells (p = 0.001) and, on the other hand, had higher CD3+ CD4+ T cells (p = 0.012) and CD4+/CD8+ ratio (p = 0.003). Non survived adults, compared with survived patients, had significantly lower CD3+ T-lymphocyte (p = 0.005). Conclusion: Unlike adult patients, who compared with matched controls and had more comorbidities, higher frequency of severe clinical symptoms, laboratory abnormalities, and immune cells alteration, clinical manifestations of COVID-19 in children (compared with matched controls) were relatively mild, and fewer clinical complications were seen either, perhaps because of a milder inflammatory response following their peripheral innate and adaptive immune cell alteration pattern.

Antiviral Immunity in SARS-CoV-2 Infection: From Protective to Deleterious Responses

After two previous episodes, in 2002 and 2012, when two highly pathogenic coronaviruses (SARS, MERS) with a zoonotic origin emerged in humans and caused fatal respiratory illness, we are today experiencing the COVID-19 pandemic produced by SARS-CoV-2. The main question of the year 2021 is if naturally- or artificially-acquired active immunity will be effective against the evolving SARS-CoV-2 variants. This review starts with the presentation of the two compartments of antiviral immunity-humoral and cellular, innate and adaptive-underlining how the involved cellular and molecular actors are intrinsically connected in the development of the immune response in SARS-CoV-2 infection. Then, the SARS-CoV-2 immunopathology, as well as the derived diagnosis and therapeutic approaches, will be discussed.

Drugs and liver injury: a not to be overlooked binomial in COVID-19

SARS-CoV-2 infection (COVID-19) results predominantly in pulmonary involvement but a direct, virus-induced liver damage may also occur, whose mechanisms are being actively investigated. Accordingly, it appears of utmost importance to monitor liver function and carefully evaluate hepatic safety of the various drugs administered during COVID-19. In this respect, many drugs, biological agents and novel molecules, whose efficacy in COVID-19 is under scrutiny, have also been shown to potentially cause or worsen liver damage. In this article, we review safety data of established as well as promising agents for COVID-19.

The role of type I interferon in the treatment of COVID-19

Although significant research has been done to find effective drugs against coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), no definite effective drug exists. Thus, research has now shifted towards immunomodulatory agents other than antivirals. In this review, we aim to describe the latest findings on the role of type I interferon (IFN)‐mediated innate antiviral response against SARS‐CoV‐2 and discuss the use of IFNs as a medication for COVID‐19. A growing body of evidence has indicated a promoting active but delayed IFNs response to SARS‐CoV‐2 and Middle East respiratory syndrome coronavirus in infected bronchial epithelial cells. Studies have demonstrated that IFNs' administration before the viral peak and the inflammatory phase of disease could offer a highly protective effect. However, IFNs' treatment during the inflammatory and severe stages of the disease causes immunopathology and long‐lasting harm for patients. Therefore, it is critical to note the best time window for IFNs' administration. Further investigation of the clinical effectiveness of interferon for patients with mild to severe COVID‐19 and its optimal timing and route of administration can be beneficial in finding a safe and effective antiviral therapy for the COVID‐19 disease.

1‐IFNs have many antiviral actions including; the activation of cytotoxic T‐cell responses, the inhibition of the viral mRNA translation, the degradation of the viral RNA, RNA editing and modulating the synthesis of Nitric Oxide.

2‐IFNS are two‐edged immunomodulatory agents; as they can provide a protective effect if administered in the early phases of the disease before the viral peak, whereas a harming effect is observed when administered in the inflammatory phase.

3‐More human trials are needed to find the best time window for administrating type I IFN for patients with various COVID‐19 modalities.

Association between meteorological factors and daily new cases of COVID-19 in 188 countries: A time series analysis

By 31 December 2020, Coronavirus disease 2019 (COVID-19) had been prevalent worldwide for one year, and most countries had experienced a complete seasonal cycle. The role of the climate and environment are essential factors to consider in transmission. We explored the association between global meteorological conditions (including mean temperature, wind speed, relative humidity and diurnal temperature range) and new cases of COVID-19 in the whole past year. We assessed the relative risk of meteorological factors to the onset of COVID-19 by using generalized additive models (GAM) and further analyzed the hysteresis effects of meteorological factors using the Distributed Lag Nonlinear Model (DLNM). Our findings revealed that the mean temperature, wind speed and relative humidity were negatively correlated with daily new cases of COVID-19, and the diurnal temperature range was positively correlated with daily new cases of COVID-19. These relationships were more apparent when the temperature and relative humidity were lower than their average value (21.07°Cand 66.83%). The wind speed and diurnal temperature range were higher than the average value(3.07 m/s and 9.53 °C). The maximum RR of mean temperature was 1.30 under -23°C at lag ten days, the minimum RR of wind speed was 0.29 under 12m/s at lag 24 days, the maximum RR of range of temperature was 2.21 under 28 °C at lag 24 days, the maximum RR of relative humidity was 1.35 under 4% at lag 0 days. After a subgroup analysis of the countries included in the study, the results were still robust. As the Northern Hemisphere enters winter, the risk of global covid-19 remains high. Some countries have ushered in a new round of COVID-19 epidemic. Thus, active measures must be taken to control the source of infection, block transmission and prevent further spread of COVID-19 in winter.

Exergames to Prevent the Secondary Functional Deterioration of Older Adults during Hospitalization and Isolation Periods during the COVID-19 Pandemic

The COVID-19 pandemic is having an intense impact on the functional capacity of older adults, making them more vulnerable to frailty and dependency. The development of preventive and rehabilitative measures which counteract the consequences of confinement or hospitalization is an urgent need. Exergaming can promote physical activity, prevent falls, and maintain functional and cognitive capacity. However, although the use of exergames in health programs for the elderly is promising, their widespread use should not be considered without the supervision of a social health professional. Therefore, the objective of this work was to evaluate and analyze three video game consoles (Nintendo Wii®, Xbox-Kinect® and Play Station 4®) and 26 commercial exergames with the aim of identifying their usefulness for the prevention of functional deterioration. Three occupational therapists analyzed the data independently, and subsequently agreed on the results. The examination of the commercial consoles met three criteria: components, interaction channels and the type of the exergame. Each exergame was analyzed taking into account its ability to train postural control, balance, upper limb functionality and cognitive function. The results of the evaluation showed that exergames contain game activities that can be part of the rehabilitative treatment aimed at the prevention of the functional impairment of older people affected by COVID.

A systematic review of pregnant women with COVID-19 and their neonates

BACKGROUND

In December 2019, a novel coronavirus disease (COVID-19) emerged in Wuhan, China, with an incredible contagion rate. However, the vertical transmission of COVID-19 is uncertain.

OBJECTIVES

This is a systematic review of published studies concerning pregnant women with confirmed COVID-19 and their neonates.

SEARCH STRATEGY

We carried out a systematic search in multiple databases, including PubMed, Web of Science, Google Scholar, Scopus, and WHO COVID-19 database using the following keywords: (Coronavirus) OR (novel coronavirus) OR (COVID-19) OR (COVID19) OR (COVID 19) OR (SARS-CoV2) OR (2019-nCoV)) and ((pregnancy) OR (pregnant) OR (vertical transmission) OR (neonate) OR (newborn) OR (placenta) OR (fetus) OR (Fetal)). The search took place in April 2020.

SELECTION CRITERIA

Original articles published in English were eligible if they included pregnant patients infected with COVID-19 and their newborns.

DATA COLLECTION AND ANALYSES

The outcomes of interest consisted of clinical manifestations of COVID-19 in pregnant patients with COVID-19 and also the effect of COVID-19 on neonatal and pregnancy outcomes.

MAIN RESULTS

37 articles involving 364 pregnant women with COVID-19 and 302 neonates were included. The vast majority of pregnant patients were in their third trimester of pregnancy, and only 45 cases were in the first or second trimester (12.4%). Most mothers described mild to moderate manifestations of COVID-19. Of 364 pregnant women, 25 were asymptomatic at the time of admission. The most common symptoms were fever (62.4%) and cough (45.3%). Two maternal deaths occurred. Some pregnant patients (12.1%) had a negative SARS-CoV-2 test but displayed clinical manifestations and abnormalities in computed tomography (CT) scan related to COVID-19. Twenty-two (6.0%) pregnant patients developed severe pneumonia. Two maternal deaths occurred from severe pneumonia and multiple organ dysfunction. Studies included a total of 302 neonates from mothers with COVID-19. Of the studies that provided data on the timing of birth, there were 65 (23.6%) preterm neonates. One baby was born dead from a mother who also died from COVID-19. Of the babies born alive from mothers with COVID-19, five newborns faced critical conditions, and two later died. A total of 219 neonates underwent nasopharyngeal specimen collection for SARS-CoV-2, of which 11 tested positive (5%). Seventeen studies examined samples of the placenta, breast milk, umbilical cord, and amniotic fluid, and all tested negative except one amniotic fluid sample.

CONCLUSIONS

A systematic review of published studies confirm that the course of COVID-19 in pregnant women resembles that of other populations. However, there is not sufficient evidence to establish an idea that COVID-19 would not complicate pregnancy.

Interferon therapy in patients with SARS, MERS, and COVID-19: A systematic review and meta-analysis of clinical studies

Concern regarding coronavirus (CoV) outbreaks has stayed relevant to global health in the last decades. Emerging COVID-19 infection, caused by the novel SARS-CoV2, is now a pandemic, bringing a substantial burden to human health. Interferon (IFN), combined with other antivirals and various treatments, has been used to treat and prevent MERS-CoV, SARS-CoV, and SARS-CoV2 infections. We aimed to assess the clinical efficacy of IFN-based treatments and combinational therapy with antivirals, corticosteroids, traditional medicine, and other treatments. Major healthcare databases and grey literature were investigated. A three-stage screening was utilized, and included studies were checked against the protocol eligibility criteria. Risk of bias assessment and data extraction were performed, followed by narrative data synthesis. Fifty-five distinct studies of SARS-CoV2, MERS-CoV, and SARS-CoV were spotted. Our narrative synthesis showed a possible benefit in the use of IFN. A good quality cohort showed lower CRP levels in Arbidol (ARB) + IFN group vs. IFN only group. Another study reported a significantly shorter chest X-ray (CXR) resolution in IFN-Alfacon-1 + corticosteroid group compared with the corticosteroid only group in SARS-CoV patients. In a COVID-19 trial, total adverse drug events (ADEs) were much lower in the Favipiravir (FPV) + IFN-α group compared with the LPV/RTV arm (P = 0.001). Also, nausea in patients receiving FPV + IFN-α regimen was significantly lower (P = 0.03). Quantitative analysis of mortality did not show a conclusive effect for IFN/RBV treatment in six moderately heterogeneous MERS-CoV studies (log OR = −0.05, 95% CI: (−0.71,0.62), I² = 44.71%). A meta-analysis of three COVID-19 studies did not show a conclusive nor meaningful relation between receiving IFN and COVID-19 severity (log OR = −0.44, 95% CI: (−1.13,0.25), I² = 31.42%). A lack of high-quality cohorts and controlled trials was observed. Evidence suggests the potential efficacy of several combination IFN therapies such as lower ADEs, quicker resolution of CXR, or a decrease in inflammatory cytokines; Still, these options must possibly be further explored before being recommended in public guidelines. For all major CoVs, our results may indicate a lack of a definitive effect of IFN treatment on mortality. We recommend such therapeutics be administered with extreme caution until further investigation uncovers high-quality evidence in favor of IFN or combination therapy with IFN.

Storm at the Time of Corona: A Glimpse at the Current Understanding and Therapeutic Opportunities of the SARS-CoV-2 Cytokine Storm

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may lead to severe disease in some cases, leading to acute respiratory distress syndrome, multi-organ failure, and death. This severe phenotype seems to be associated with a cytokine storm and immune dysregulation. Increased pro-inflammatory cytokines and CD14+CD16+ inflammatory monocytes, lymphopenia, and decreased levels of regulatory T cells are some of the immunological features that are seen in patients with SARS-CoV-2. As the outcome of SARS-CoV-2 is influenced by both viral virulence and dysregulated inflammatory response, a combination therapy approach using antiviral drugs plus anti-inflammatory treatments, such as corticosteroids, monoclonal antibodies against the IL-6 and IL-1β pathways, and JAK inhibitors are under clinical trials.

Purification and characterization of the receptor-binding domain of SARS-CoV-2 spike protein from Escherichia coli

SARS-CoV-2 is responsible for a disruptive worldwide viral pandemic, and renders a severe respiratory disease known as COVID-19. Spike protein of SARS-CoV-2 mediates viral entry into host cells by binding ACE2 through the receptor-binding domain (RBD). RBD is an important target for development of virus inhibitors, neutralizing antibodies, and vaccines. RBD expressed in mammalian cells suffers from low expression yield and high cost. E. coli is a popular host for protein expression, which has the advantage of easy scalability with low cost. However, RBD expressed by E. coli (RBD-1) lacks the glycosylation, and its antigenic epitopes may not be sufficiently exposed. In the present study, RBD-1 was expressed by E. coli and purified by a Ni Sepharose Fast Flow column. RBD-1 was structurally characterized and compared with RBD expressed by the HEK293 cells (RBD-2). The secondary structure and tertiary structure of RBD-1 were largely maintained without glycosylation. In particular, the major β-sheet content of RBD-1 was almost unaltered. RBD-1 could strongly bind ACE2 with a dissociation constant (KD) of 2.98 × 10-8 M. Thus, RBD-1 was expected to apply in the vaccine development, screening drugs and virus test kit.

Clinical and Laboratory Predictors of Severity, Criticality, and Mortality in COVID-19: A Multisystem Disease

Coronavirus disease 2019 (COVID-19) pandemic continues devastating effects on healthcare systems. Such a crisis calls for an urgent need to develop a risk stratification tool. The present chapter aimed to identify laboratory and clinical correlates of adverse outcomes in patients with COVID-19. To this end, we conducted a systematic evaluation of studies that investigated laboratory abnormalities in patients with COVID-19 and compared i. patients with a severe form of disease and patients with a non-severe form of the disease, ii. patients who were in critical condition and patients who were not in critical condition, and iii. patients who survived and patients who died. We included 54 studies in the data synthesis. Compared to patients with a non-severe form of COVID-19, patients who had a severe form of disease revealed higher values for white blood cells (WBC), polymorphonuclear leukocytes (PMN), total bilirubin, alanine aminotransferase (ALT), creatinine, troponin, procalcitonin, lactate dehydrogenase (LDH), and D-dimer. By contrast, platelet count, lymphocyte count, and albumin levels were decreased in patients with a severe form of COVID-19. Also, patients with a severe phenotype of disease were more likely to have diabetes, chronic heart disease, chronic obstructive pulmonary disease (COPD), cerebrovascular disease, hypertension, chronic kidney disease (CKD), and malignancy. Compared to patients who survived, patients who died had higher WBC, PMN, total bilirubin, ALT, procalcitonin, IL-6, creatinine, PT, lymphocyte count, platelet count, and albumin. Also, non-survivors revealed a higher prevalence of diabetes, chronic heart disease, COPD, cerebrovascular disease, and CKD. Meta-analyses identified several laboratory parameters that might help the prediction of severe, critical, and lethal phenotypes of COVID-19. These parameters correlate with the immune system function, inflammation, coagulation, and liver and kidney function.

Geriatrics and COVID-19

Since December 2019, a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has begun to infect people. The virus first occurred in Wuhan, China, but the whole world is now struggling with the pandemic. Over 13 million confirmed cases and 571,000 deaths have been reported so far, and this number is growing. Older people, who constitute a notable proportion of the world population, are at an increased risk of infection because of altered immunity and chronic comorbidities. Thus, appropriate health care is necessary to control fatalities and spread of the disease in this specific population. The chapter provides an overview of diagnostic methods, laboratory and imaging findings, clinical features, and management of COVID-19 in aged people. Possible mechanisms behind the behavior of SARS-CoV-2 in the elderly include immunosenescence and related impaired antiviral immunity, mature immunity and related hyper-inflammatory responses, comorbidities and their effects on the functioning of critical organs/systems, and the altered expression of angiotensin-converting enzyme 2 (ACE2) that acts as an entry receptor for SARS-CoV-2. This evidence defines the herding behavior of COVID-19 in relation to ACE2 under the influence of immune dysregulation. Then, identifying the immunogenetic factors that affect the disease susceptibility and severity and as well as key inflammatory pathways that have the potential to serve as therapeutic targets needs to remain an active area of research.

Introduction on Coronavirus Disease (COVID-19) Pandemic: The Global Challenge

By driving the ongoing pandemic of coronavirus disease 2019 (COVID-19), coronaviruses have become a significant change in twenty-first-century medicine, healthcare systems, education, and the global economy. This chapter rapidly reviews the origin, immunopathogenesis, epidemiology, diagnosis, clinical manifestations, and potential therapeutics of COVID-19. It would also explore the effects of the introduction of a single virus, the so-called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), on the public health preparedness planning.

Clinical Manifestations of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the third coronavirus causing an outbreak in the twenty-first century. It is related to a contagious coronavirus disease (COVID-19), which its high pace of spreading allowed it to lie to the whole world and be turned into a pandemic only a few months after the identification of the first case. Currently, the reverse transcription-polymerase chain reaction (RT-PCR) test of throat swap is the gold standard of diagnosis; however, several studies have reported false-negative results with non-ideal sensitivity. Because this pandemic constitutes a significant burden on global healthcare systems and due to the high transmission rate of the virus, an accurate diagnosis algorithm is needed to reduce the missing case number. A comprehensive clinical examination and taking a history of all systems (not just limited to the respiratory system) combined with hematologic laboratory tests and chest imaging can lead to a sensitive diagnosis, severity assessment, and RT-PCT test interpretation. This chapter focuses on clinical characteristics, hematologic laboratory, and chest imaging features in COVID-19.

COVID-19 in Patients with Cancer

With more than 5 million cases and 333,212 deaths, COVID-19 (or SARS-CoV-2) continues to spread. General symptoms of this disease are similar to that of many other viral respiratory diseases, including fever, cough, dyspnea, and fatigue, with a chance of progression to more severe complications. However, the virus does not affect all people equally, and cases with comorbidities such as malignancies, cardiovascular diseases, respiratory diseases, and kidney diseases are at higher risk of developing severe events, including requiring intensive ventilation, intensive care unit (ICU) admission, and death. Patients with cancer are more likely to be infected with COVID-19, which is possibly due to their immunological dysfunction or frequent clinic visits. Also, there is a higher chance that these patients experience severe events because of the medication they receive. In this chapter, we will review the main clinical manifestations of COVID-19 in patients with cancer. Recommendations and challenges for managing resources, organizing cancer centers, treatment of COVID-19-infected cancer patients, and performing cancer research during this pandemic will also be discussed.

Prevention of COVID-19: Preventive Strategies for General Population, Healthcare Setting, and Various Professions

The disease 2019 (COVID-19) made a public health emergency in early 2020. Despite attempts for the development of therapeutic modalities, there is no effective treatment yet. Therefore, preventive measures in various settings could help reduce the burden of disease. In this chapter, the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19, non-pharmaceutical approaches at individual and population level, chemoprevention, immunoprevention, preventive measures in different healthcare settings and other professions, special considerations in high-risk groups, and the role of organizations to hamper the psychosocial effects will be discussed.

Neurologic Manifestations of COVID-19

Neurological manifestations of novel coronavirus disease (COVID-19) are reported to occur in as much as 37% of the affected patients. These manifestations range from headache and dizziness to altered mental status and consciousness, anosmia, ageusia, sensory disturbances, and stroke. The mechanisms by which the neurological symptoms arise are not yet determined but may either proceed as an indirect consequence of systemic hyperinflammation or result from the direct invasion of the virus to neural and glial cells. The neural invasion can explain both the retrograde pathway of encephalitis and the early manifestation of anosmia by invading the olfactory bulb. Moreover, in the case of attacking the brain stem, it may take part in the early apnea manifestation reported by patients. Additionally, neurotropism of the virus could be the cause of acute hemorrhagic encephalitis. Hyperinflammation can have acute and prolonged effects in the nervous system, such as acute demyelination and predisposition to multiple sclerosis. Moreover, the pro-inflammatory state contributes to hypercoagulation, which in turn could result in cerebrovascular injuries in COVID-19 patients. This chapter would discuss that the neurologic manifestations of the COVID-19 are to be looked at as a multifactorial entangled phenomenon.

Coronavirus: Pure Infectious Disease or Genetic Predisposition

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes novel coronavirus disease (COVID-19), is the seventh pathogenic coronavirus recently discovered in December 2019 in Wuhan, China. To date, our knowledge about its effect on the human host remains limited. It is well known that host genetic factors account for the individual differences in the susceptibility to infectious diseases. The genetic susceptibility factors to COVID-19 and its severity are associated with several unanswered questions. However, the experience gained from an earlier strain of coronavirus, SARS-CoV-1, which shows 78% genetic similarity to SARS-CoV-2 and uses the same receptor to bind to host cells, could provide some clues. It, therefore, seems possible to assemble new evidence in order to solve a potential genetic predisposition puzzle for COVID-19. In this chapter, the puzzle pieces, including virus entry receptors, immune response, and inflammation-related genes, as well as the probable genetic predisposition models to COVID-19, are discussed.

Nutrition and Immunity in COVID-19

Nutrition can strongly influence infection trajectories by either boosting or suppressing the immune system. During the recently emerged pandemic of coronavirus disease 2019 (COVID-19), individuals who possess diets high in fat, refined carbohydrates, and sugars have shown to be highly prone to the disease and associated adverse outcomes. Both micronutrients and macronutrients provide benefits at different stages of the infection. Thus, using appropriate nutritional recommendations and interventions is necessary to combat the infection in patients with COVID-19 in both outpatient and inpatient settings.

The Epidemiologic Aspects of COVID-19 Outbreak: Spreading Beyond Expectations

The coronavirus disease 2019 (COVID-19) outbreak started in late 2019 in Wuhan, Hubei Province of China, and quickly spread to the surrounding regions and neighboring countries. A novel coronavirus, the so-called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was found to be responsible for this outbreak potentially originating from pangolins. In China, the outbreak lasted for 1 month until it seemed to be controlled after affecting over 81,000 individuals and causing deaths in over 4200 patients. Subsequently, and after affecting over 118,000 individuals and causing over 4200 deaths, the condition was officially announced as a pandemic by the World Health Organization (WHO). In the meantime, the epidemic curve took a downtrend in China, the original epicenter of the pandemic, but started to rise in other countries with a steep slope. Among over 215 affected countries, the USA, European countries (Italy, Germany, Spain, France, the UK), Iran, and South Korea had the highest frequencies in the matters of infected patients and deaths. Importantly, different countries took different policies when encountered with an outbreak, especially in the matter of accuracy of the report and timing of the action. A part of the delays in reporting was expected, including the lag in the chain of reporting, the shortcomings of tests, missed patients, and inadequate testing facilities. However, there were also political and nontechnical reasons that caused the reporting to be inaccurate. Surveillance seems to be less of a reason for the observed in poor management, and it mostly originated from human decision-making failures and political issues. Besides, the culture of populations and their trust in their governments played an important role on how they reacted to the COVID-19 pandemic and acquired policies. Finally, the characteristics of the world today indicate the danger of probable upcoming outbreaks, and policymakers should utilize the existing opportunities, particularly the advancements in technology and media, to prevent or adequately manage them.

How COVID-19 Has Globalized: Unknown Origin, Rapid Transmission, and the Immune System Nourishment

The novel coronavirus disease (COVID-19) profoundly influences T-cell immunity. The counts of total T cells and T-cell subsets, especially CD4+ and CD8+ T cells, are decreased in patients with COVID-19. Also, the function of these cells becomes less effective as the expression of immune inhibitory receptors, such as Tim3 and PD-1, increases over time during the disease. Kinetic analyses show that the T-cell profile changes dynamically, so does the COVID-19 stages. As COVID-19 continues to deteriorate and progresses to severe/critical condition, the lymphocyte count steadily decreases. Therefore, the ability of COVID-19 to escape the immune system might lie in its power to profoundly diminish T-cell effective function, which is necessary for the establishment of a robust antiviral immunity. Also, COVID-19 is associated with increased numbers of monocytes and macrophages, and as the disease progresses from a mild form to a severe/critical condition, the macrophage population becomes denser. Monitoring the expression of cytokines associated with macrophage activation, mainly interleukin (IL)-6 and IL-10, indicates that the course of COVID-19 consists of two stages and the transition between disease stages occurs by the end of the first week after onset of symptoms. At the initial stage, the immune military recognizes the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as nonself and thus fires macrophages at the lungs against the virus. The first flame can control disease progression effectively. However, a trained immunocompetent system would maintain the fire of macrophages over an extended time. It lies in its immune memory in tissue-resident macrophages, especially alveolar macrophages, making a professionally trained immune system more likely to be feared by COVID-19 than an untrained immune system. In this manner, the trained immunocompetent system commits such a failure that causes the lungs to come down rapidly. The fact that younger age groups, including neonates and children, are less susceptible to COVID-19 than older age groups reflects that the natural affinities of the immune system that has not been trained thoroughly would be standard in combatting against COVID-19 whereas the higher affinities of the trained immune system for rapid activation of immune responses might raise faults - the lungs come down.

How Prevalent Is Cancer in Confirmed Cases with Coronaviruses and Severe Acute Respiratory Syndromes?

Novel coronavirus disease 2019 (COVID-19) has posed a crucial hazard to global health. The new species share similarities with the two previously emerged entities: severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS) that have caused outbreaks in 2002 and 2012, respectively. Interestingly, all of these coronaviruses can cause potentially fatal respiratory syndromes, though behave differently in patients with cancer compared to patients without cancer. Accordingly, the present chapter aims to, through a systematic investigation, estimate the prevalence of cancer among COVID-19, SARS, and MERS confirmed cases. Our analysis based on data from 78 studies with SARS, MERS, and COVID-19 confirmed cases showed that the prevalence of cancer (4.94%) stands at fourth place after hypertension (20.8%), diabetes (11.39%), and cardiovascular diseases (7.46%). According to the findings of the present study, comorbidities are significantly more common in patients with MERS compared to patients with COVID-19 and SARS, and this was the cancer case as well. Further studies need to address whether or not patients with coronaviruses and cancer are different from patients with coronaviruses without cancer in terms of clinical manifestations, laboratory findings, outcomes, and men to women ratio.

Mesenchymal Stem Cells and COVID-19: Cure, Prevention, and Vaccination

COVID-19 disease has been a global health problem since late 2019. There are many concerns about the rapid spread of this disease, and yet, there is no approved treatment for COVID-19. Several biological interventions have been under study recently to investigate efficient treatment for this viral disease. Besides, many efforts have been made to find a safe way to prevent and vaccinate people against COVID-19 disease. In severe cases, patients suffer from acute respiratory distress syndrome usually associated with an increased level of inflammatory cytokines, called a cytokine storm. It seems that reequilibrating the hyperinflammatory response of the host immune system and regeneration of damaged cells could be the main way to manage the disease. Mesenchymal stem cells (MSCs) have been recently under investigation in this regard, and the achieved clinical outcomes show promising evidence for stem cell-based therapy of COVID-19. MSCs are known for their potential for immunomodulation, defense against virus infection, and tissue regeneration. MSCs are a newly emerged platform for designing vaccines and show promising evidence in this area. In the present study, we provided a thorough research study on the most recent clinical studies based on stem cells in the treatment of COVID-19 while introducing stem cell exclusivities for use as an immune disorder or lung cell therapy and its potential application for protection and vaccination against COVID-19.

The role of autophagy in controlling SARS-CoV-2 infection: An overview on virophagy-mediated molecular drug targets

Autophagy-dependent cell death is a prominent mechanism that majorly contributes to homeostasis by maintaining the turnover of organelles under stressful conditions. Several viruses, including coronaviruses (CoVs), take advantage of cellular autophagy to facilitate their own replication. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a beta-coronavirus (β-CoVs) that mediates its replication through a dependent or independent ATG5 pathway using specific double-membrane vesicles that can be considered as similar to autophagosomes. With due attention to several mutations in NSP6, a nonstructural protein with a positive regulatory effect on autophagosome formation, a potential correlation between SARS-CoV-2 pathogenesis mechanisms and autophagy can be expected. Certain medications, albeit limited in number, have been indicated to negatively regulate autophagy flux, potentially in a way similar to the inhibitory effect of β-CoVs on the process of autophagy. However, there is no conclusive evidence to support their direct antagonizing effect on CoVs. Off-target accumulation of a major fraction of FDA-approved autophagy modulating drugs may result in adverse effects. Therefore, medications that have modulatory effects on autophagy could be considered as potential lead compounds for the development of new treatments against this virus. This review discusses the role of autophagy/virophagy in controlling SARS-CoV-2, focusing on the potential therapeutic implications.

Altered immunoemotional regulatory system in COVID-19: From the origins to opportunities

The emergence of the novel coronavirus (SARS-CoV-2) and the worldwide spread of the coronavirus disease (COVID-19) have led to social regulations that caused substantial changes in manners of daily life. The subsequent loneliness and concerns of the pandemic during social distancing, quarantine, and lockdown are psychosocial stressors that negatively affect the immune system. These effects occur through mechanisms controlled by the sympathetic nervous system (SNS) and the hypothalamic-pituitary-adrenocortical (HPA) axis that alter immune regulation, namely the conserved transcriptional response to adversity (CTRA), which promotes inflammation and diminishes antiviral responses, leading to inadequate protection against viral disease. Unhealthy eating habits, physical inactivity, sleep disturbances, and mental health consequences of COVID-19 add on to the pathological effects of loneliness, making immunity against this ferocious virus an even tougher fight. Therefore, social isolation, with its unintended consequences, has inherently paradoxical effects on immunity in relation to viral disease. Though this paradox can present a challenge, its acknowledgment can serve as an opportunity to address the associated issues and find ways to mitigate the adverse effects. In this review, we aim to explore, in detail, the pathological effects of the new social norms on immunity and present suggested methods to improve our physical, psychological, and healthcare abilities to fight viral infection in the context of the COVID-19 pandemic.

Effects of Coronavirus Disease 2019 (COVID-19) on Peripheral Blood Lymphocytes and Their Subsets in Children: Imbalanced CD4+/CD8+ T Cell Ratio and Disease Severity

Introduction: While pathogenesis in COVID-19 is not fully known and the effects between SARS-CoV-2 and the immune system are complicated, it is known that lymphopenia, hyper-inflammatory responses, and cytokines play an important role in the pathology of COVID-19. While some hematological abnormalities have been described among the laboratory features of COVID-19, there have not been studies reported on lymphocyte subset analyses in children. The aim of this study was to describe lymphocyte subsets in pediatric patients with mild/moderate or severe COVID-19. Methods: The subjects in the study were children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia confirmed with the real-time RT-PCR. The subjects were admitted to the Children's Medical Center, affiliated with the Tehran University of Medical Sciences, between March 7th and June 10th of 2020. The complete blood counts and lymphocyte subpopulations were analyzed for each patient. Results: The study included 55 hospitalized patients with confirmed SARS-CoV-2 infection (34 patients (62%) with an observed mild/moderate case of the disease and 21 patients (38%) with severedisease). Lymphocyte counts were found to be lower in patients with a severe case (mean ± SD 1.6 ± 0.9 in the severe group vs. 2.3 ± 2.2 in the mild group). Compared to the group with mild/moderate pneumonia, children with severe pneumonia had an increased count of CD8+ T cell and a lower percentage of CD4+ T cell. However, the differences between the groups were negligible. Interestingly, the severe group had a lower CD4+/CD8+ T cell ratio compared to the mild group (1.1 ± 0.47 vs. 1.4 ± 0.8, p-value: 0.063). CD4+/CD8+ T cell ratio <2, 1.5, and 1 was found in 48 (87%), 40 (73%), and 19 cases (35%). All of the seven cases in which the subject passed (13%) had CD4+/CD8+ T cell ratio of <2, 86% had CD4+/CD8+ T cell ratio of <1.5, and 29% had CD4+/CD8+ T cell ratio of <1. Conclusion: The CD4+/CD8+ T cell ratio was lower in patients with severe COVID-19 compared to those with mild/moderate form of disease. However, although a decline in CD4+/CD8+ ratio may serve as a useful metric in analyzing of the derangement in immune responses in patients with severe COVID-19, further study with larger sample sizes is highly recommended.