The many faces of the anti-COVID immune response

Longitudinal transcriptional analysis of peripheral blood leukocytes in COVID-19 convalescent donors

BACKGROUND

SARS-CoV2 can induce a strong host immune response. Many studies have evaluated antibody response following SARS-CoV2 infections. This study investigated the immune response and T cell receptor diversity in people who had recovered from SARS-CoV2 infection (COVID-19).

METHODS

Using the nCounter platform, we compared transcriptomic profiles of 162 COVID-19 convalescent donors (CCD) and 40 healthy donors (HD). 69 of the 162 CCDs had two or more time points sampled.

RESULTS

After eliminating the effects of demographic factors, we found extensive differential gene expression up to 241 days into the convalescent period. The differentially expressed genes were involved in several pathways, including virus-host interaction, interleukin and JAK-STAT signaling, T-cell co-stimulation, and immune exhaustion. A subset of 21 CCD samples was found to be highly "perturbed," characterized by overexpression of PLAU, IL1B, NFKB1, PLEK, LCP2, IRF3, MTOR, IL18BP, RACK1, TGFB1, and others. In addition, one of the clusters, P1 (n = 8) CCD samples, showed enhanced TCR diversity in 7 VJ pairs (TRAV9.1_TCRVA_014.1, TRBV6.8_TCRVB_016.1, TRAV7_TCRVA_008.1, TRGV9_ENST00000444775.1, TRAV18_TCRVA_026.1, TRGV4_ENST00000390345.1, TRAV11_TCRVA_017.1). Multiplexed cytokine analysis revealed anomalies in SCF, SCGF-b, and MCP-1 expression in this subset.

CONCLUSIONS

Persistent alterations in inflammatory pathways and T-cell activation/exhaustion markers for months after active infection may help shed light on the pathophysiology of a prolonged post-viral syndrome observed following recovery from COVID-19 infection. Future studies may inform the ability to identify druggable targets involving these pathways to mitigate the long-term effects of COVID-19 infection.

TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT04360278 Registered April 24, 2020.

CT-based pathological lung opacities volume as a predictor of critical illness and inflammatory response severity in patients with COVID-19

Objective

The aim of the study was to assess the impact of CT-based lung pathological opacities volume on critical illness and inflammatory response severity of patients with COVID-19.

Methods

A retrospective, single center, single arm study was performed over a 30-day period. In total, 138 patients (85.2%) met inclusion criteria. All patients were evaluated with non-contrast enhanced chest CT scan at hospital admission. CT-based lung segmentation was performed to calculate pathological lung opacities volume (LOV). At baseline, complete blood count (CBC) and inflammation response biomarkers were obtained. The primary endpoint of the study was the occurrence of critical illness, as defined as, the need of mechanical ventilation and/or ICU admission. Mann-Whitney U test was performed for univariate analysis. Logistic regression analysis was performed to determine independent predictors of critical illness. Spearman analysis was performed to assess the correlation between inflammatory response biomarkers serum concentrations and LOV.

Results

Median LOV was 28.64% (interquartile range [IQR], 6.33-47.22%). Correlation analysis demonstrated that LOV was correlated with higher levels of D-dimer (r = 0.51, p < 0.01), procalcitonin (r = 0.47, p < 0.01) and IL6 (r = 0.48, p < 0.01). Critical illness occurred in 51 patients (37%). Univariate analysis demonstrated that inflammatory response biomarkers and LOV were associated with critical illness (p < 0.05). However, multivariate analysis demonstrated that only D-dimer and LOV were independent predictors of critical illness. Furthermore, a ROC analysis demonstrated that a LOV equal or greater than 60% had a sensitivity of 82.1% and specificity of 70.2% to determine critical illness with an odds ratio of 19.4 (95% CI, 4.2-88.9).

Conclusion

Critical illness may occur in up to 37% of the patients with COVID-19. Among patients with critical illness, higher levels of inflammatory response biomarkers with larger LOVs were observed. Furthermore, multivariate analysis demonstrated that pathological lung opacities volume was an independent predictor of critical illness. In fact, patients with a pathological lung opacities volume equal or greater than 60% had 19.4-fold increased risk of critical illness.

SARS-CoV-2 induces "cytokine storm" hyperinflammatory responses in RA patients through pyroptosis

Background

The coronavirus disease (COVID-19) is a pandemic disease that threatens worldwide public health, and rheumatoid arthritis (RA) is the most common autoimmune disease. COVID-19 and RA are each strong risk factors for the other, but their molecular mechanisms are unclear. This study aims to investigate the biomarkers between COVID-19 and RA from the mechanism of pyroptosis and find effective disease-targeting drugs.

Methods

We obtained the common gene shared by COVID-19, RA (GSE55235), and pyroptosis using bioinformatics analysis and then did the principal component analysis(PCA). The Co-genes were evaluated by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and ClueGO for functional enrichment, the protein-protein interaction (PPI) network was built by STRING, and the k-means machine learning algorithm was employed for cluster analysis. Modular analysis utilizing Cytoscape to identify hub genes, functional enrichment analysis with Metascape and GeneMANIA, and NetworkAnalyst for gene-drug prediction. Network pharmacology analysis was performed to identify target drug-related genes intersecting with COVID-19, RA, and pyroptosis to acquire Co-hub genes and construct transcription factor (TF)-hub genes and miRNA-hub genes networks by NetworkAnalyst. The Co-hub genes were validated using GSE55457 and GSE93272 to acquire the Key gene, and their efficacy was assessed using receiver operating curves (ROC); SPEED2 was then used to determine the upstream pathway. Immune cell infiltration was analyzed using CIBERSORT and validated by the HPA database. Molecular docking, molecular dynamics simulation, and molecular mechanics-generalized born surface area (MM-GBSA) were used to explore and validate drug-gene relationships through computer-aided drug design.

Results

COVID-19, RA, and pyroptosis-related genes were enriched in pyroptosis and pro-inflammatory pathways(the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome complex, death-inducing signaling complex, regulation of interleukin production), natural immune pathways (Network map of SARS-CoV-2 signaling pathway, activation of NLRP3 inflammasome by SARS-CoV-2) and COVID-19-and RA-related cytokine storm pathways (IL, nuclear factor-kappa B (NF-κB), TNF signaling pathway and regulation of cytokine-mediated signaling). Of these, CASP1 is the most involved pathway and is closely related to minocycline. YY1, hsa-mir-429, and hsa-mir-34a-5p play an important role in the expression of CASP1. Monocytes are high-caspase-1-expressing sentinel cells. Minocycline can generate a highly stable state for biochemical activity by docking closely with the active region of caspase-1.

Conclusions

Caspase-1 is a common biomarker for COVID-19, RA, and pyroptosis, and it may be an important mediator of the excessive inflammatory response induced by SARS-CoV-2 in RA patients through pyroptosis. Minocycline may counteract cytokine storm inflammation in patients with COVID-19 combined with RA by inhibiting caspase-1 expression.

SARS-CoV-2 in brief: from virus to prevention

The recent outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), ahighly transmissible virus with a likely animal origin, has posed major and unprecedentedchallenges to millions of lives across the affected nations of the world. This outbreak firstoccurred in China, and despite massive regional and global attempts shortly thereafter, itspread to other countries and caused millions of deaths worldwide. This review presents keyinformation about the characteristics of SARS-CoV-2 and its associated disease (namely,coronavirus disease 2019) and briefly discusses the origin of the virus. Herein, we also brieflysummarize the strategies used against viral spread and transmission.

Characteristics of COVID-19 (Delta Variant)/HIV Co-infection: A Cross-sectional Study in Henan Province, China

Background

Since the end of July 2021, SARS-CoV-2 (Delta variant) invaded Henan Province, China, causing a rapid COVID-19 spread in the province. Among them, the clinical features of COVID-19 (Delta Variant)/HIV co-infection have attracted our attention.

Methods

We included 12 COVID-19 patients living with HIV (human immunodeficiency virus) from July 30, 2021 to September 17, 2021 in Henan Province, China. Demographic, clinical, laboratory, and computed tomography (CT) imaging data were dynamically collected from first nucleic acid positive to hospital discharge. Laboratory findings included SARS-CoV-2 viral load, HIV viral load, IgM, IgG, cytokines, lymphocyte subpopulation, ferritin, etc. Statistical analyses were performed using IBM SPSS version 26·0 and GraphPad Prism version 9·0.

Results

It was founded that the low Ct value persisted for about 21 days, and the viral shedding time (turn negative time) of the patients was 32·36 ± 2·643 days. Furthermore, chest CT imaging revealed that lesions were obviously and rapidly absorbed. It was surprising that IgM levels were statistically higher in patients taking azvudine or convalescent plasma than in patients not taking these drugs (P < 0·001, P = 0·0002, respectively). IgG levels were significantly higher in patients treated with the combined medication of BRII/196 and BRII/198 than in those not treated with these drugs (P = 0·0029). IgM was significantly higher in those with low HIV viral load than those with high HIV viral load (P < 0·001). In addition, as treatment progressed and patients' condition improved, IL-17a showed a decreasing trend.

Conclusions

Based on this study, we found that HIV infection might not exacerbate COVID-19 severity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44231-022-00018-z.

Role of neuroinflammation mediated potential alterations in adult neurogenesis as a factor for neuropsychiatric symptoms in Post-Acute COVID-19 syndrome-A narrative review

Persistence of symptoms beyond the initial 3 to 4 weeks after infection is defined as post-acute COVID-19 syndrome (PACS). A wide range of neuropsychiatric symptoms like anxiety, depression, post-traumatic stress disorder, sleep disorders and cognitive disturbances have been observed in PACS. The review was conducted based on PRISMA-S guidelines for literature search strategy for systematic reviews. A cytokine storm in COVID-19 may cause a breach in the blood brain barrier leading to cytokine and SARS-CoV-2 entry into the brain. This triggers an immune response in the brain by activating microglia, astrocytes, and other immune cells leading to neuroinflammation. Various inflammatory biomarkers like inflammatory cytokines, chemokines, acute phase proteins and adhesion molecules have been implicated in psychiatric disorders and play a major role in the precipitation of neuropsychiatric symptoms. Impaired adult neurogenesis has been linked with a variety of disorders like depression, anxiety, cognitive decline, and dementia. Persistence of neuroinflammation was observed in COVID-19 survivors 3 months after recovery. Chronic neuroinflammation alters adult neurogenesis with pro-inflammatory cytokines supressing anti-inflammatory cytokines and chemokines favouring adult neurogenesis. Based on the prevalence of neuropsychiatric symptoms/disorders in PACS, there is more possibility for a potential impairment in adult neurogenesis in COVID-19 survivors. This narrative review aims to discuss the various neuroinflammatory processes during PACS and its effect on adult neurogenesis.

Neutrophil Extracellular Traps, Local IL-8 Expression, and Cytotoxic T-Lymphocyte Response in the Lungs of Patients With Fatal COVID-19

BACKGROUND

Excessive inflammation is pathogenic in the pneumonitis associated with severe COVID-19. Neutrophils are among the most abundantly present leukocytes in the inflammatory infiltrates and may form neutrophil extracellular traps (NETs) under the local influence of cytokines. NETs constitute a defense mechanism against bacteria, but have also been shown to mediate tissue damage in a number of diseases.

RESEARCH QUESTION

Could NETs and their tissue-damaging properties inherent to neutrophil-associated functions play a role in the respiratory failure seen in patients with severe COVID-19, and how does this relate to the SARS-CoV-2 viral loads, IL-8 (CXCL8) chemokine expression, and cytotoxic T-lymphocyte infiltrates?

STUDY DESIGN AND METHODS

Sixteen lung biopsy samples obtained immediately after death were analyzed methodically as exploratory and validation cohorts. NETs were analyzed quantitatively by multiplexed immunofluorescence and were correlated with local levels of IL-8 messenger RNA (mRNA) and the density of CD8+ T-cell infiltration. SARS-CoV-2 presence in tissue was quantified by reverse-transcriptase polymerase chain reaction and immunohistochemistry analysis.

RESULTS

NETs were found in the lung interstitium and surrounding the bronchiolar epithelium with interindividual and spatial heterogeneity. NET density did not correlate with SARS-CoV-2 tissue viral load. NETs were associated with local IL-8 mRNA levels. NETs were also detected in pulmonary thrombi and in only one of eight liver tissues. NET focal presence correlated negatively with CD8+ T-cell infiltration in the lungs.

INTERPRETATION

Abundant neutrophils undergoing NETosis are found in the lungs of patients with fatal COVID-19, but no correlation was found with viral loads. The strong association between NETs and IL-8 points to this chemokine as a potentially causative factor. The function of cytotoxic T-lymphocytes in the immune responses against SARS-CoV-2 may be interfered with by the presence of NETs.

Are Antisense Long Non-Coding RNA Related to COVID-19?

Fighting external pathogens relies on the tight regulation of the gene expression of the immune system. Ferroptosis, which is a distinct form of programmed cell death driven by iron, is involved in the enhancement of follicular helper T cell function during infection. The regulation of RNA is a key step in final gene expression. The present study aimed to identify the expression level of antisense lncRNAs (A2M-AS1, DBH-AS1, FLVCR1-DT, and NCBP2AS2-1) and FLVCR1 in COVID-19 patients and its relation to the severity of the disease. COVID-19 patients as well as age and gender-matched healthy controls were enrolled in this study. The expression level of the antisense lncRNAs was measured by RT-PCR. Results revealed the decreased expression of A2M-AS1 and FLVCR1 in COVID-19 patients. Additionally, they showed the increased expression of DBH-AS1, FLVCR1-DT, and NCBP2AS2. Both FLVCR1-DT and NCBP2AS2 showed a positive correlation with interleukin-6 (IL-6). DBH-AS1 and FLVCR1-DT had a significant association with mortality, complications, and mechanical ventilation. A significant negative correlation was found between A2M-AS1 and NCBP2AS2-1 and between FLVCR1 and FLVCR1-DT. The study confirmed that the expression level of the antisense lncRNAs was deregulated in COVID-19 patients and correlated with the severity of COVID-19, and that it may have possible roles in the pathogenesis of this disease.

From Cytokine Storm to Cytokine Breeze: Did Lessons Learned from Immunopathogenesis Improve Immunomodulatory Treatment of Moderate-to-Severe COVID-19?

Complex immune response to infection has been highlighted, more than ever, during the COVID-19 pandemic. This review explores the immunomodulatory treatment of moderate-to-severe forms of this viral sepsis in the context of specific immunopathogenesis. Our objective is to analyze in detail the existing strategies for the use of immunomodulators in COVID-19. Immunomodulating therapy is very challenging; there are still underpowered or, in other ways, insufficient studies with inconclusive or conflicting results regarding a rationale for adding a second immunomodulatory drug to dexamethasone. Bearing in mind that a "cytokine storm" is not present in the majority of COVID-19 patients, it is to be expected that the path to the adequate choice of a second immunomodulatory drug is paved with uncertainty. Anakinra, a recombinant human IL-1 receptor antagonist, is a good choice in this setting. Yet, the latest update of the COVID-19 Treatment Guidelines Panel (31 May 2022) claims that there is insufficient evidence to recommend either for or against the use of anakinra for the treatment of COVID-19. EMA's human medicines committee recommended extending the indication of anakinra to include treatment of COVID-19 in adult patients only recently (17 December 2021). It is obvious that this is still a work in progress, with few ongoing clinical trials. With over 6 million deaths from COVID-19, this is the right time to speed up this process. Our conclusion is that, during the course of COVID-19, the immune response is changing from the early phase to the late phase in individual patients, so immunomodulating therapy should be guided by individual responses at different time points.

SARS-CoV-2 and HIV-1: So Different yet so Alike. Immune Response at the Cellular and Molecular Level

In the past half century, humanity has experienced two devastating pandemics; the HIV-1 pandemic and the recent pandemic caused by SARS-CoV-2. Both emerged as zoonotic pathogens. Interestingly, SARS-CoV-2 has rapidly migrated all over the world in less than two years, much as HIV-1 did almost 40 years ago. Despite these two RNA viruses being different in their mode of transmission as well as the symptoms they generate, recent evidence suggests that they cause similar immune responses. In this mini review, we compare the molecular basis for CD4+ T cell lymphopenia and other effects on the immune system induced by SARS-CoV-2 and HIV-1 infections. We considered features of the host immune response that are shared with HIV-1 and could account for the lymphopenia and other immune effects observed in COVID-19. The information provided herein, may cast the virus-induced lymphopenia and cytokine storm associated with the acute SARS-CoV-2 infection and pathogenesis in a different light for further research on host immune responses. It can also provide opportunities for the identification of novel therapeutic targets for COVID-19. Furthermore, we provide some basic information to enable a comparative framework for considering the overlapping sets of immune responses caused by HIV-1 and SARS-CoV-2.

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.

Prostaglandins and non-steroidal anti-inflammatory drugs in Covid-19

In response to different viral infections, including SARS-CoV-2 infection, pro-inflammatory, anti-inflammatory cytokines, and bioactive lipids are released from infected and immune cells. One of the most critical bioactive lipids is prostaglandins (PGs) which favor perseverance of inflammation leading to chronic inflammation as PGs act as cytokine amplifiers. PGs trigger the release of pro-inflammatory cytokines, activate Th cells, recruit immune cells, and increase the expression of pro-inflammatory genes. Therefore, PGs may induce acute and chronic inflammations in various inflammatory disorders and viral infections like SARS-CoV-2. PGs are mainly inhibited by non-steroidal anti-inflammatory drugs (NSAIDs) by blocking cyclooxygenase enzymes (COXs), which involve PG synthesis. NSAIDs reduce inflammation by selective or non-selective blocking activity of COX2 or COX1/2, respectively. In the Covid-19 era, there is a tremendous controversy regarding the use of NSAIDs in the management of SARS-CoV-2 infection. As well, the possible role of PGs in the pathogenesis of SARS-CoV-2 infection is not well-defined. Thus, the objective of the present study is to review the potential role of PGs and NSAIDs in Covid-19 in a narrative review regarding the preponderance of assorted views.

A Case Report on Multisystem Inflammatory Syndrome After COVID-19 Infection in a 12-Year-Old Child

Several new diagnostic and management challenges have evolved as a result of limited knowledge about the incidence of multisystem inflammatory syndrome in children (MISC) and its natural history which is caused by coronavirus disease 2019 (COVID-19) infection. There are no data on the long-term outcomes of the illness and MISC. A 12-year-old female child with no significant history was rushed to a emergency room with complaints of rashes all over her body for the past seven days, fever for the past five days, and altered sensorium for the last one day. The child tested negative for COVID-19 at first and then was found to be antibody positive for COVID-19. The child showed symptoms of the multisystem inflammatory syndrome, which involved the main alteration in liver functioning. This case is suggestive of how the COVID-19 virus causes alteration in liver functioning and its inflammation, including inflammation of other organs, which is called MISC.

Hesperetin from Root Extract of Clerodendrum petasites S. Moore Inhibits SARS-CoV-2 Spike Protein S1 Subunit-Induced NLRP3 Inflammasome in A549 Lung Cells via Modulation of the Akt/MAPK/AP-1 Pathway

Inhibition of inflammatory responses from the spike glycoprotein of SARS-CoV-2 (Spike) by targeting NLRP3 inflammasome has recently been developed as an alternative form of supportive therapy besides the traditional anti-viral approaches. Clerodendrum petasites S. Moore (C. petasites) is a Thai traditional medicinal plant possessing antipyretic and anti-inflammatory activities. In this study, C. petasites ethanolic root extract (CpEE) underwent solvent-partitioned extraction to obtain the ethyl acetate fraction of C. petasites (CpEA). Subsequently, C. petasites extracts were determined for the flavonoid contents and anti-inflammatory properties against spike induction in the A549 lung cells. According to the HPLC results, CpEA significantly contained higher amounts of hesperidin and hesperetin flavonoids than CpEE (p < 0.05). A549 cells were then pre-treated with either C. petasites extracts or its active flavonoids and were primed with 100 ng/mL of spike S1 subunit (Spike S1) and determined for the anti-inflammatory properties. The results indicate that CpEA (compared with CpEE) and hesperetin (compared with hesperidin) exhibited greater anti-inflammatory properties upon Spike S1 induction through a significant reduction in IL-6, IL-1β, and IL-18 cytokine releases in A549 cells culture supernatant (p < 0.05). Additionally, CpEA and hesperetin significantly inhibited the Spike S1-induced inflammatory gene expressions (NLRP3, IL-1β, and IL-18, p < 0.05). Mechanistically, CpEA and hesperetin attenuated inflammasome machinery protein expressions (NLRP3, ASC, and Caspase-1), as well as inactivated the Akt/MAPK/AP-1 pathway. Overall, our findings could provide scientific-based evidence to support the use of C. petasites and hesperetin in the development of supportive therapies for the prevention of COVID-19-related chronic inflammation.

SARS-CoV-2 Virus in Cancer Patients: A New Unknown in an Unsolved Equation

INTRODUCTION

Cancer patients are more susceptible to infections, and infection can be more severe than in patients without cancer diagnosis. We conducted this retrospective study in patients admitted for SARS-CoV-2 infection in order to find differences in inflammatory markers and mortality in cancer patients compared to others.

METHODS

We reviewed the electronic records of patients admitted for SARS-CoV-2 infection confirmed by PCR from March to September 2020. Data on socio-demographics, comorbidities, inflammatory makers, and cancer-related features were analyzed.

RESULTS

2,772 patients were admitted for SARS-CoV-2, to the Hospital Universitario Ramón y Cajal in Madrid during this period. Of these, 2,527 (91%) had no history of neoplastic disease, 164 (5.9%) patients had a prior history of cancer but were not undergoing oncological treatment at the time of infection, and 81 (2.9%) were in active treatment. Mortality in patients without a history of cancer was 19.5%, 28.6% for patients with a prior history of cancer, and 34% in patients with active cancer treatment. Patients in active oncology treatment with the highest mortality rate were those diagnosed with lung cancer (OR 5.6 95% CI: 2.2-14.1). In the multivariate study, active oncological treatment (OR 2.259 95% CI: 1.35-3.77) and chemotherapy treatment (OR 3.624 95% CI: 1.17-11.17), were statistically significant factors for the risk of death for the whole group and for the group with active oncological treatment, respectively.

CONCLUSION

Cancer patients on active systemic treatment have an increased risk of mortality after SARS-CoV-2 infection, especially with lung cancer or chemotherapy treatment.

Redox regulation of the immune response

The immune-inflammatory response is associated with increased nitro-oxidative stress. The aim of this mechanistic review is to examine: (a) the role of redox-sensitive transcription factors and enzymes, ROS/RNS production, and the activity of cellular antioxidants in the activation and performance of macrophages, dendritic cells, neutrophils, T-cells, B-cells, and natural killer cells; (b) the involvement of high-density lipoprotein (HDL), apolipoprotein A1 (ApoA1), paraoxonase-1 (PON1), and oxidized phospholipids in regulating the immune response; and (c) the detrimental effects of hypernitrosylation and chronic nitro-oxidative stress on the immune response. The redox changes during immune-inflammatory responses are orchestrated by the actions of nuclear factor-κB, HIF1α, the mechanistic target of rapamycin, the phosphatidylinositol 3-kinase/protein kinase B signaling pathway, mitogen-activated protein kinases, 5' AMP-activated protein kinase, and peroxisome proliferator-activated receptor. The performance and survival of individual immune cells is under redox control and depends on intracellular and extracellular levels of ROS/RNS. They are heavily influenced by cellular antioxidants including the glutathione and thioredoxin systems, nuclear factor erythroid 2-related factor 2, and the HDL/ApoA1/PON1 complex. Chronic nitro-oxidative stress and hypernitrosylation inhibit the activity of those antioxidant systems, the tricarboxylic acid cycle, mitochondrial functions, and the metabolism of immune cells. In conclusion, redox-associated mechanisms modulate metabolic reprogramming of immune cells, macrophage and T helper cell polarization, phagocytosis, production of pro- versus anti-inflammatory cytokines, immune training and tolerance, chemotaxis, pathogen sensing, antiviral and antibacterial effects, Toll-like receptor activity, and endotoxin tolerance.

Humanized mice for investigating SARS-CoV-2 lung infection and associated human immune responses

There is an urgent need for animal models of coronavirus disease 2019 to study immunopathogenesis and test therapeutic intervenes. In this study, we showed that NOD/SCID IL2rg^-/- (NSG) mice engrafted with human lung (HL) tissue (NSG-L mice) could be infected efficiently by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and that live virus capable of infecting Vero cells was found in the HL grafts and multiple organs from infected NSG-L mice. RNA-Sequencing identified a series of differentially expressed genes, which are enriched in viral defense responses, chemotaxis, IFN stimulation and pulmonary fibrosis, between HL grafts from infected and control NSG-L mice. Furthermore, when infected with SARS-CoV-2, humanized mice with both human immune system (HIS) and autologous HL grafts (HISL mice) had bodyweight loss and hemorrhage and immune cell infiltration in HL grafts, which were not observed in immunodeficient NSG-L mice, indicating the development of anti-viral immune responses in these mice. In support of this possibility, the infected HISL mice showed bodyweight recovery and lack of detectable live virus at the later time. These results demonstrate that NSG-L and HISL mice are susceptible to SARS-CoV-2 infection, offering a useful in vivo model for studying SARS-CoV-2 infection and the associated immune response and immunopathology, and testing anti-SARS-CoV-2 therapies.

SARS-CoV-2 infection in multiple sclerosis patients: interaction with treatments, adjuvant therapies, and vaccines against COVID-19

The SARS-CoV-2 pandemic has raised particular concern for people with Multiple Sclerosis, as these people are believed to be at increased risk of infection, especially those being treated with disease-modifying therapies. Therefore, the objective of this review was to describe how COVID-19 affects people who suffer from Multiple Sclerosis, evaluating the risk they have of suffering an infection by this virus, according to the therapy to which they are subjected as well as the immune response of these patients both to infection and vaccines and the neurological consequences that the virus can have in the long term. The results regarding the increased risk of infection due to treatment are contradictory. B-cell depletion therapies may cause patients to have a lower probability of generating a detectable neutralizing antibody titer. However, more studies are needed to help understand how this virus works, paying special attention to long COVID and the neurological symptoms that it causes.

Immune modulation as a consequence of SARS-CoV-2 infection

Erroneous immune responses in COVID-19 could have detrimental effects, which makes investigation of immune network underlying COVID-19 pathogenesis a requisite. This study aimed to investigate COVID-19 related alterations within the frame of innate and adaptive immunity. Thirty-four patients clinically diagnosed with mild, moderate and severe COVID-19 disease were enrolled in this study. Decreased ILC1 and increased ILC2 subsets were detected in mild and moderate patients compared to healthy controls. NK cell subsets and cytotoxic capacity of NK cells were decreased in severe patients. Moreover, CD3+ T cells were reduced in severe patients and a negative correlation was found between CD3+ T cells and D-dimer levels. Likewise, moderate and severe patients showed diminished CD3+CD8+ T cells. Unlike T and NK cells, plasmablast and plasma cells were elevated in patients and IgG and IgA levels were particularly increased in severe patients. Severe patients also showed elevated serum levels of pro-inflammatory cytokines such as TNF-α, IL-6 and IL-8, reduced intracellular IFN-γ and increased intracellular IL-10 levels. Our findings emphasize that SARS-CoV-2 infection significantly alters immune responses and innate and acquired immunity are differentially modulated in line with the clinical severity of the disease. Elevation of IL-10 levels in NK cells and reduction of CD3+ and CD8+ T cells in severe patients might be considered as a protective response against the harmful effect of cytokine storm seen in COVID-19.

On virus and nanomaterials - Lessons learned from the innate immune system - ACE activation in the invertebrate model Enchytraeus crypticus

Current human research on COVID-19 - SARS-CoV-2 (Severe Acute Respiratory Syndrome-Corona Virus) showed that ACE2 (Angiotensin Converting Enzyme 2) is a functional receptor to which the spike proteins attach. Invertebrates have been exposed to a wide array of threats for millennia and their immune system has evolved to deal with these efficiently. The annelid Enchytraeus crypticus, a standard ecotoxicological species, is an invertebrate species where extensive mechanisms of response studies are available, covering all levels from gene to population responses. Nanomaterials (NMs) are often perceived as invaders (e.g. virus) and can enter the cell covered by a corona, triggering similar responses. We created a database on E. crypticus ACE gene expression, aiming to analyse the potential knowledge transfer between invertebrates and vertebrates. Total exposure experiments sum 87 stress conditions for 18 different nanomaterials (NMs). ACE expression following TiO2 NM exposure was clearly different from other NMs showing a clear (6-7 fold) ACE down-regulation, not observed for any other NMs. Other NMs, notably Ag NMs, and to some extent Cu NMs, caused ACE up-regulation (up to 4 fold). The extensive knowledge from response to NMs can support the immuno-research community, especially to develop therapies for virus that trigger the innate immune system.

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.

COVID-19 and the Immune Response: A Multi-Phasic Approach to the Treatment of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a viral agent that causes Coronavirus disease 2019 (COVID-19), a disease that causes flu-like symptoms that, when exacerbated, can have life-threatening consequences. COVID-19 has been linked to persistent symptoms, sequelae, and medical complications that can last months after the initial infection. This systematic review aims to elucidate the innate and adaptive immune mechanisms involved and identify potential characteristics of COVID-19 pathology that may increase symptom duration. We also describe he three different stages of COVID-19—viral replication, immune hyperactivation, and post-acute sequelae—as well as each phase’s corresponding immune response. Finally, we use this multiphasic approach to describe different treatment approaches for each of the three stages—antivirals, immunosuppressants and monoclonal antibodies, and continued immunosuppressants—to fully curate the treatment to the stage of disease.

The Role of Inflammasomes in COVID-19: Potential Therapeutic Targets

The coronavirus 2019 disease (COVID-19) pandemic has caused massive morbidity and mortality worldwide. In severe cases, it is mainly associated with acute pneumonia, cytokine storm, and multi-organ dysfunction. Inflammasomes play a primary role in various pathological processes such as infection, injury, and cancer. However, their role in COVID-19-related complications has not been explored. In addition, the role of underlying medical conditions on COVID-19 disease severity remains unclear. Therefore, this review expounds on the mechanisms of inflammasomes following COVID-19 infection and provides recent evidence on the potential double-edged sword effect of inflammasomes during COVID-19 pathogenesis. The assembly and activation of inflammasomes are critical for inducing effective antiviral immune responses and disease resolution. However, uncontrolled activation of inflammasomes causes excessive production of proinflammatory cytokines (cytokine storm), increased risk of acute respiratory distress syndrome, and death. Therefore, discoveries in the role of the inflammasome in mediating organ injury are key to identifying therapeutic targets and treatment modifications to prevent or reduce COVID-19-related complications.

Immunomodulatory mechanisms of abatacept: A therapeutic strategy for COVID-19

Coronavirus disease 2019 (COVID-19) caused by coronavirus-2 (SARS-CoV-2) infection has rapidly spread throughout the world and become a major threat to human beings. Cytokine storm is a major cause of death in severe patients. Abatacept can suppress cytokines used as antirheumatic drugs in clinical applications. This study analyzed the molecular mechanisms of abatacept treatment for COVID-19. Differentially expressed genes (DEGs) were identified by analyzing expression profiling of abatacept treatment for rheumatoid arthritis (RA) patients and SARS-CoV-2 infection patients. We found that 59 DEGs were upregulated in COVID-19 patients and downregulated following abatacept treatment. Gene set enrichment analysis (GSEA) and Gene Ontology (GO) analysis showed that immune and inflammatory responses were potential regulatory mechanisms. Moreover, we verified 8 targeting genes and identified 15 potential drug candidates for the treatment of COVID-19. Our study illustrated that abatacept could be a promising property for preventing severe COVID-19, and we predicted alternative potential drugs for the treatment of SARS-CoV-2 infection.

Proteomic Profile of Procoagulant Extracellular Vesicles Reflects Complement System Activation and Platelet Hyperreactivity of Patients with Severe COVID-19

Background

Extracellular vesicles (EVs) are a valuable source of biomarkers and display the pathophysiological status of various diseases. In COVID-19, EVs have been explored in several studies for their ability to reflect molecular changes caused by SARS-CoV-2. Here we provide insights into the roles of EVs in pathological processes associated with the progression and severity of COVID-19.

Methods

In this study, we used a label-free shotgun proteomic approach to identify and quantify alterations in EV protein abundance in severe COVID-19 patients. We isolated plasma extracellular vesicles from healthy donors and patients with severe COVID-19 by size exclusion chromatography (SEC). Then, flow cytometry was performed to assess the origin of EVs and to investigate the presence of circulating procoagulant EVs in COVID-19 patients. A total protein extraction was performed, and samples were analyzed by nLC-MS/MS in a Q-Exactive HF-X. Finally, computational analysis was applied to signify biological processes related to disease pathogenesis.

Results

We report significant changes in the proteome of EVs from patients with severe COVID-19. Flow cytometry experiments indicated an increase in total circulating EVs and with tissue factor (TF) dependent procoagulant activity. Differentially expressed proteins in the disease groups were associated with complement and coagulation cascades, platelet degranulation, and acute inflammatory response.

Conclusions

The proteomic data reinforce the changes in the proteome of extracellular vesicles from patients infected with SARS-CoV-2 and suggest a role for EVs in severe COVID-19.

Exploring the management approaches of cytokines including viral infection and neuroinflammation for neurological disorders

Considerable evidence supports that cytokines are important mediators of pathophysiologic processes within the central nervous system (CNS). Numerous studies have documented the increased production of various cytokines in the human CNS in various neurological and neuropsychiatric disorders. Deciphering cytokine actions in the intact CNS has important implications for our understanding of the pathogenesis and treatment of these disorders. The purpose of this study is to discuss the recent research on treating cytokine storm and amyloids, including stroke, Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's condition, Multi-sclerosis (MS), Amyotrophic Lateral Sclerosis (ALS). Neuroinflammation observed in neurological disorders has a pivotal role in exacerbating Aβ burden and tau hyperphosphorylation, suggesting that stimulating cytokines in response to an undesirable external response could be a checkpoint for treating neurological disorders. Furthermore, the pro-inflammatory cytokines help our immune system through a neuroprotective mechanism in clearing viral infection by recruiting mononuclear cells. This study reveals that cytokine applications may play a vital role in providing novel regulation and methods for the therapeutic approach to neurological disorders and the causes of the deregulation, which is responsible for neuroinflammation and viral infection. However, it needs to be further investigated to clarify better the mechanisms of cytokine release in response to various stimuli, which could be the central point for treating neurological disorders.

Evaluation of Perioperative Complications and Mortality in Covid-19 Patients Who Had Emergency Surgery

Objective: The risk for adverse outcomes in COVID-19 patients necessitates further scrutiny in Covid 19 patients in providing appropriate surgical indications and perioperative surgical safety precautions. In this study, we aimed to contribute to elective surgery resumption about infection with early and late postoperative complications and mortality in patients with RT-PCR (+) and clinically suspicious COVID-19 who underwent emergency surgery in our hospital. Methods: A total of 86 patients who have been operated on in our institution for emergency surgery over the age of 18 who were diagnosed with SARS-CoV-2 infection seven days before or 30 days after surgery were enrolled in the study. In this retrospective study, the primary outcome has been established as mortality factors and survival within postoperative 30 days. Results: Regarding the primary outcome as 30-day survival, every 1-year increase in age increased the risk of death by two folds. Patients with one or more comorbidities have an increased risk of death 13 times and those with two or more have an increased risk of death 23 times. Patients in intensive care units increase the risk of death by 8.5 times compared to those who are not hospitalized. On the contrary, an increase in hemoglobin level was shown to reduce the risk of death by 0.8 times. Conclusion: The need for intensive care and mortality is high, especially after emergency surgery, in patients with COVID19 symptoms and more than one comorbidity. Surgical indications of such patients should be well investigated.

Tocilizumab effectiveness in mechanically ventilated COVID-19 patients (T-MVC-19 Study): a multicenter real-world evidence

BACKGROUND

This study aimed to evaluate the effectiveness of tocilizumab in mechanically ventilated patients with coronavirus disease 2019 (COVID-19).

RESEARCH DESIGN AND METHODS

This retrospective multicenter study included adults (≥18 years) diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by real-time polymerase chain reaction (RT-PCR) from nasopharyngeal swab, and requiring invasive mechanical ventilation during admission. Survival analyses with inverse propensity score treatment weighting (IPTW) and propensity score matching (PSM) were conducted. To account for immortal bias, we used Cox proportional modeling with time-dependent covariance. Competing risk analysis was performed for the extubation endpoint.

RESULTS

A total of 556 (tocilizumab = 193, control = 363) patients were included. Males constituted the majority of the participants (69.2% in tocilizumab arm,74.1% in control arm). Tocilizumab was not associated with a reduction in mortality with hazard ratio [(HR) = 0.82,95% confidence interval (95%CI): 0.62-1.10] in the Inverse propensity score weighting (IPTW) analysis and (HR = 0.86,95% CI: 0.64-1.16) in the PSM analysis. However, tocilizumab was associated with an increased rate of extubation (33.6%) compared to the control arm (11.9%); subdistributional hazards (SHR) = 3.1, 95% CI: 1.86-5.16).

CONCLUSIONS

Although tocilizumab was not found to be effective in reducing mortality, extubation rate while on mechanical ventilation was higher among tocilizumab treated group.

Antibody Responses to SARS-CoV-2 After Infection or Vaccination in Children and Young Adults With Inflammatory Bowel Disease

BACKGROUND

Characterization of neutralization antibodies to SARS-CoV-2 infection or vaccination in children and young adults with inflammatory bowel disease (IBD) receiving biologic therapies is crucial.

METHODS

We performed a prospective longitudinal cohort study evaluating SARS-CoV-2 spike protein receptor binding domain (S-RBD) IgG positivity along with consistent clinical symptoms in patients with IBD receiving infliximab or vedolizumab. Serum was also obtained following immunization with approved vaccines. The IgG antibody to the spike protein binding domain of SARS-CoV-2 was assayed with a fluorescent bead-based immunoassay that takes advantage of the high dynamic range of fluorescent molecules using flow cytometry. A sensitive and high-throughput neutralization assay that incorporates SARS-CoV-2 spike protein onto a lentivirus and measures pseudoviral entry into ACE2-angiotensin converting enzyme 2 (ACE2) expressing human embryonic kidney 293 (HEK-293) cells was used.

RESULTS

There were 436 patients enrolled (mean age, 17 years, range 2-26 years; 58% male; 71% Crohn's disease, 29% ulcerative colitis, IBD-unspecified). Forty-four (10%) of enrolled subjects had SARS-CoV-2 S-RBD IgG antibodies. Compared to non-IBD adults (ambulatory) and hospitalized pediatric patients with PCR documented SARS-CoV-2 infection, S-RBD IgG antibody levels were significantly lower in the IBD cohort and by 6 months post infection most patients lacked neutralizing antibody. Following vaccination (n = 33), patients had a 15-fold higher S-RBD antibody response in comparison with natural infection, and all developed neutralizing antibodies to both wild type and variant SARS-CoV-2.

CONCLUSIONS

The lower and less durable SARS-CoV-2 S-RBD IgG response to natural infection in IBD patients receiving biologics puts them at risk of reinfection. The robust response to immunization is likely protective.

Hallmarks of Severe COVID-19 Pathogenesis: A Pas de Deux Between Viral and Host Factors

Two years into Coronavirus Disease 2019 (COVID-19) pandemic, a comprehensive characterization of the pathogenesis of severe and critical forms of COVID-19 is still missing. While a deep dysregulation of both the magnitude and functionality of innate and adaptive immune responses have been described in severe COVID-19, the mechanisms underlying such dysregulations are still a matter of scientific debate, in turn hampering the identification of new therapies and of subgroups of patients that would most benefit from individual clinical interventions. Here we review the current understanding of viral and host factors that contribute to immune dysregulation associated with COVID-19 severity in the attempt to unfold and broaden the comprehension of COVID-19 pathogenesis and to define correlates of protection to further inform strategies of targeted therapeutic interventions.

Case fatality rate of the adult in-patients with COVID-19 and digestive system tumors: A systematic review and meta-analysis

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, endoscopic screening for gastrointestinal tumors was suspended or delayed in most countries. Thus, our study aimed to quantify the impact of COVID-19 on the clinical outcomes of patients with digestive system tumors through a systematic review and meta-analysis.

METHODS

We systematically searched the PubMed, Web of Science, Cochrane Library, and Embase databases as of March 7, 2021 to identify the case fatality rate (CFR) of COVID-19 patients diagnosed with digestive system tumors. A random-effects model was used for meta-analysis, I2 was used to assess heterogeneity, and funnel plot was used to assess publication bias.

RESULTS

A total of 13 studies were included, involving 2943 tumor patients with COVID-19, of which 871 were digestive system tumors, and the CFR was 24% (95% CI, 18%-30%; I2 = 55.7%). The mortality rate of colorectal cancer was 21% (95% CI, 14%-27%; I2 = 0.0%), gastric cancer was 25% (95% CI, 6%-45%; I2 = 0.0%), and hepatobiliary cancer was 29%. In general, there was no significant difference in the CFR of digestive system tumors.

CONCLUSION

The combined CFR of digestive system tumors and COVID-19 patients was 24%, which is much higher than that of the general population. Under the premise of fully complying with the international guidelines to limit the spread of COVID-19, we call for the resumption of endoscopic screening programs and selective surgery as soon as possible.

REGISTRATION INFORMATION

PROSPERO registration no. CRD42021248194.

A comprehensive review about immune responses and exhaustion during coronavirus disease (COVID-19)

Coronavirus disease (COVID-19) is a viral infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The infection was reported in Wuhan, China, in late December 2019 and has become a major global concern due to severe respiratory infections and high transmission rates. Evidence suggests that the strong interaction between SARS-CoV-2 and patients' immune systems leads to various clinical symptoms of COVID-19. Although the adaptive immune responses are essential for eliminating SARS-CoV-2, the innate immune system may, in some cases, cause the infection to progress. The cytotoxic CD8+ T cells in adaptive immune responses demonstrated functional exhaustion through upregulation of exhaustion markers. In this regard, humoral immune responses play an essential role in combat SARS-CoV-2 because SARS-CoV-2 restricts antigen presentation through downregulation of MHC class I and II molecules that lead to the inhibition of T cell-mediated immune response responses. This review summarizes the exact pathogenesis of SARS-CoV-2 and the alteration of the immune response during SARS-CoV-2 infection. In addition, we've explained the exhaustion of the immune system during SARS-CoV-2 and the potential immunomodulation approach to overcome this phenomenon. Video Abstract.

The Impact of Colchicine on COVID-19 patients: A Clinical Trial Study

Background

Severe acute respiratory syndrome due to COVID-19 infection has evolved into a global pandemic. This study has been designed to evaluate colchicine as an anti-inflammatory agent among COVID-19 patients regarding the disease course, duration of hospitalisation, and its morbidity and mortality rate.

Methods

This prospective randomised and double-blind clinical trial study included 100 COVID-19 hospitalized patients with moderate symptoms from May 21 to June 20, 2020. They were randomised in a 1:1 allocation to placebo and colchicine groups plus recommended standard guideline and protocol of health system. Colchicine 1 mg has been taken daily for 6 days. All data including associated symptoms, co-existed disease and duration of hospitalisation evaluated initially, and then 2 weeks after discharge; moreover, their mortality and morbidity, re-admission, and deteriorations of symptoms were assessed during this period.

Results

59% were female with median age 56 years old. There was no significant difference between them in terms of age and sex. Two groups did not show significant difference about underlying diseases and various clinical and para clinical findings evaluation. However, there were significant difference in colchicine group regarding for shorter duration of fever (P<0.05) and hospitalisation (P<0.05). Although in colchicine group dyspnoea improved more rapidly than the placebo group, it was not meaningful.

Conclusion

Colchicine can be effective in amelioration of systemic symptoms and duration of hospitalisation probably by inhibition of inflammatory biomarkers in COVID-19 patients.

Differential Functional Responses of Neutrophil Subsets in Severe COVID-19 Patients

Neutrophils play a significant role in determining disease severity following SARS-CoV-2 infection. Gene and protein expression defines several neutrophil clusters in COVID-19, including the emergence of low density neutrophils (LDN) that are associated with severe disease. The functional capabilities of these neutrophil clusters and correlation with gene and protein expression are unknown. To define host defense and immunosuppressive functions of normal density neutrophils (NDN) and LDN from COVID-19 patients, we recruited 64 patients with severe COVID-19 and 26 healthy donors (HD). Phagocytosis, respiratory burst activity, degranulation, neutrophil extracellular trap (NET) formation, and T-cell suppression in those neutrophil subsets were measured. NDN from severe/critical COVID-19 patients showed evidence of priming with enhanced phagocytosis, respiratory burst activity, and degranulation of secretory vesicles and gelatinase and specific granules, while NET formation was similar to HD NDN. COVID LDN response was impaired except for enhanced NET formation. A subset of COVID LDN with intermediate CD16 expression (CD16^Int LDN) promoted T cell proliferation to a level similar to HD NDN, while COVID NDN and the CD16^Hi LDN failed to stimulate T-cell activation. All 3 COVID-19 neutrophil populations suppressed stimulation of IFN-γ production, compared to HD NDN. We conclude that NDN and LDN from COVID-19 patients possess complementary functional capabilities that may act cooperatively to determine disease severity. We predict that global neutrophil responses that induce COVID-19 ARDS will vary depending on the proportion of neutrophil subsets.

COVID-19 and Preexisting Comorbidities: Risks, Synergies, and Clinical Outcomes

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its associated symptoms, named coronavirus disease 2019 (COVID-19), have rapidly spread worldwide, resulting in the declaration of a pandemic. When several countries began enacting quarantine and lockdown policies, the pandemic as it is now known truly began. While most patients have minimal symptoms, approximately 20% of verified subjects are suffering from serious medical consequences. Co-existing diseases, such as cardiovascular disease, cancer, diabetes, and others, have been shown to make patients more vulnerable to severe outcomes from COVID-19 by modulating host-viral interactions and immune responses, causing severe infection and mortality. In this review, we outline the putative signaling pathways at the interface of COVID-19 and several diseases, emphasizing the clinical and molecular implications of concurring diseases in COVID-19 clinical outcomes. As evidence is limited on co-existing diseases and COVID-19, most findings are preliminary, and further research is required for optimal management of patients with comorbidities.

Tailored treatment strategies for cancer patients during COVID-19 pandemic

The global pandemic of respiratory disease caused by the novel human coronavirus (SARS-CoV-2) has caused indefinite global distress, uncertainty, and disturbance. This pandemic has had direct and indirect impacts for the healthcare systems across the world, but certain subgroups of patients have been particularly affected. Among these groups are patients with cancer, who as a result of their immunosuppressed status either from the disease itself or as a consequence of treatment, are at increased risk of severe COVID-19 infection and complications. The pandemic has also led to limited resources as medical services have been primarily directed to emergency care. In this context, physicians and healthcare providers have had to balance the importance of continuing treatment of cancer patients with the risk of virus infection. In this review, we outline the treatment strategies for cancer patients during this pandemic, focusing on tailored treatment in this challenging situation of varying risks and benefits.

<em>In vitro</em> and <em>in vivo</em> pharmacodynamic activity of the new compound XC221GI in models of the viral inflammation of the respiratory tract

The viruses most commonly affecting the human respiratory tract include rhinoviruses, respiratory syncytial virus (RSV), influenza viruses, and coronaviruses (CoVs). The virus infection of the epithelial cells of the respiratory tract triggers an inflammation accompanied by the release of pro-inflammatory cytokines and chemokines including IL6, IL8(CXCL8), IL1β, and tumor necrosis factor α (TNFα). A subsequent acute inflammatory response in the lungs is accompanied by an increase in the production of cytokines and chemokines − CXCR3 receptor ligands – that are key players of acute inflammatory response that induce an influx of neutrophils and T cells into the lungs.

We studied the pharmacodynamic activity of the new compound XC221GI to suppress the IL6 and IL8 of an experimental RSV infection in vitro in human lung carcinoma cells A549 and in vivo in the lungs of cotton rats. We also studied the effect of XC221GI on the production of the chemokines CXCL10, CXCL9, and CXCL11 in mouse bronchoalveolar lavage as well as on the influx of neutrophils into the mouse lungs after the intranasal administration of interferon γ (IFNγ).

The obtained results demonstrate the anti-inflammatory activity of XC221GI, which suppresses the production of excessive levels of the key inflammatory markers IL6, IL8, CXCL10, CXCL9, and CXCL11 as well as the influx of neutrophils into the lungs thereby reducing lung pathology. These data confirm the effectiveness of XC221GI as a means of preventive anti-inflammatory therapy during a viral infection of the respiratory tract.

SARS-CoV-2 (COVID-19)-specific T cell and B cell responses in convalescent rheumatoid arthritis: Monozygotic twins pair case observation

Rheumatoid arthritis (RA) patients present higher risk of SARS-CoV-2 infection (COVID-19), and proper management of the disease in this population requires a better understanding of how the immune system controls the virus. We analyzed the T cell and B cell phenotypes, and their repertoire in a pair of monozygotic twins with RA mismatched for COVID-19 infection. Twin- was not infected, while Twin+ was infected and effectively controlled the infection. We found no significant changes on the αβ T cell composition, while γδ T cells and B cells presented considerable expansion of memory population in Twin+ and robust T/B cell responses to several SARS-CoV-2 peptides. T cell receptor β/γ-chain and immunoglobulin heavy chain next-generation sequencing depicted a remarkable higher diversity in Twin+ compared with Twin-, despite no significant changes being found in variable/joining family usage. Repertoire overlap analyses showed that, although being identical twins, very few clones were shared between them, indicating that COVID-19 may lead to deep changes on the immune cell repertoire in RA patients. Altogether, our results indicate that RA patients may develop robust and persistent COVID-19-specific T/B cell responses; γδ T cells and B cells may play a key role in the management of COVID-19 in RA, and the infection may lead to a profound reshaping of immune cell receptor specificities.

Is the epithelial barrier hypothesis the key to understanding the higher incidence and excess mortality during COVID-19 pandemic? The case of Northern Italy

The high incidence and increased mortality of COVID-19 make Italy among the most impacted countries by SARS-CoV-2 outbreak. In the beginning of the pandemic, Northern regions accounted for 40% of cases and 45% of deaths from COVID-19 in Italy. Several factors have been suggested to explain the higher incidence and excess mortality from COVID-19 in these regions. It is noticed that Northern Italian regions, and particularly the cities in Po Valley, are the areas with the highest air pollution due to commercial vehicle traffic, industry and a stagnant meteorological condition, with one of the highest levels in Italy and Europe of fine particulate matter 2.5 micron or smaller in size (PM2.5). PM2.5, the major environmental pollutant deriving mainly by factory and automobile exhaust emissions and coal combustion, increases the expression of angiotensin-converting enzyme 2, the epithelial cell entry receptor for SARS-CoV-2, and thus increase the susceptibility to this virus. The epithelial barrier hypothesis proposes that many diverse diseases may rise from the disruption of epithelial barrier of skin, respiratory tract and gastrointestinal system, including allergic diseases, metabolic and autoimmune diseases, and chronic neuropsychiatric conditions. There is evidence of a close correlation between air pollution and airway epithelial barrier dysfunction. Air pollution, causing lung epithelial barrier dysfunction, may contribute to local chronic inflammation, microbiome dysbiosis and impaired antiviral immune response against SARS-CoV-2, all of which contribute to the high incidence and excess mortality from COVID-19. In addition, air pollution and epithelial barrier dysfunction contribute also to the higher prevalence of several comorbidities of COVID-19, such as diabetes, chronic obstructive pulmonary disease and obesity, which have been identified as risk factors for mortality of COVID-19. In this article, on the basis of epidemiological and environmental monitoring data in Northern Italy, it is suggested that epithelial barrier hypothesis may help to understand the excess burden and mortality from COVID-19.

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

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

Persistent Lung Injury and Prothrombotic State in Long COVID

Lung injury may persist during the recovery period of COVID-19 as shown through imaging, six-minute walk, and lung function tests. The pathophysiological mechanisms leading to long COVID have not been adequately explained. Our aim is to investigate the basis of pulmonary susceptibility during sequelae and the possibility that prothrombotic states may influence long-term pulmonary symptoms of COVID-19. The patient’s lungs remain vulnerable during the recovery stage due to persistent shedding of the virus, the inflammatory environment, the prothrombotic state, and injury and subsequent repair of the blood-air barrier. The transformation of inflammation to proliferation and fibrosis, hypoxia-involved vascular remodeling, vascular endothelial cell damage, phosphatidylserine-involved hypercoagulability, and continuous changes in serological markers all contribute to post-discharge lung injury. Considering the important role of microthrombus and arteriovenous thrombus in the process of pulmonary functional lesions to organic lesions, we further study the possibility that prothrombotic states, including pulmonary vascular endothelial cell activation and hypercoagulability, may affect long-term pulmonary symptoms in long COVID. Early use of combined anticoagulant and antiplatelet therapy is a promising approach to reduce the incidence of pulmonary sequelae. Essentially, early treatment can block the occurrence of thrombotic events. Because impeded pulmonary circulation causes large pressure imbalances over the alveolar membrane leading to the infiltration of plasma into the alveolar cavity, inhibition of thrombotic events can prevent pulmonary hypertension, formation of lung hyaline membranes, and lung consolidation.

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

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

JAK inhibitors and COVID-19

During SARS-CoV-2 infection, the innate immune response can be inhibited or delayed, and the subsequent persistent viral replication can induce emergency signals that may culminate in a cytokine storm contributing to the severe evolution of COVID-19. Cytokines are key regulators of the immune response and virus clearance, and, as such, are linked to the—possibly altered—response to the SARS-CoV-2. They act via a family of more than 40 transmembrane receptors that are coupled to one or several of the 4 Janus kinases (JAKs) coded by the human genome, namely JAK1, JAK2, JAK3, and TYK2. Once activated, JAKs act on pathways for either survival, proliferation, differentiation, immune regulation or, in the case of type I interferons, antiviral and antiproliferative effects. Studies of graft-versus-host and systemic rheumatic diseases indicated that JAK inhibitors (JAKi) exert immunosuppressive effects that are non-redundant with those of corticotherapy. Therefore, they hold the potential to cut-off pathological reactions in COVID-19. Significant clinical experience already exists with several JAKi in COVID-19, such as baricitinib, ruxolitinib, tofacitinib, and nezulcitinib, which were suggested by a meta-analysis (Patoulias et al.) to exert a benefit in terms of risk reduction concerning major outcomes when added to standard of care in patients with COVID-19. Yet, only baricitinib is recommended in first line for severe COVID-19 treatment by the WHO, as it is the only JAKi that has proven efficient to reduce mortality in individual randomized clinical trials (RCT), especially the Adaptive COVID-19 Treatment Trial (ACTT-2) and COV-BARRIER phase 3 trials. As for secondary effects of JAKi treatment, the main caution with baricitinib consists in the induced immunosuppression as long-term side effects should not be an issue in patients treated for COVID-19.

We discuss whether a class effect of JAKi may be emerging in COVID-19 treatment, although at the moment the convincing data are for baricitinib only. Given the key role of JAK1 in both type I IFN action and signaling by cytokines involved in pathogenic effects, establishing the precise timing of treatment will be very important in future trials, along with the control of viral replication by associating antiviral molecules.

Distinct Expression Patterns of Interleukin-22 Receptor 1 on Blood Hematopoietic Cells in SARS-CoV-2 Infection

The new pandemic virus SARS-CoV-2 is characterized by uncontrolled hyper-inflammation in severe cases. As the IL-22/IL-22R1 axis was reported to be involved in inflammation during viral infections, we characterized the expression of IL-22 receptor1, IL-22 and IL-22 binding protein in COVID-19 patients. Blood samples were collected from 19 non-severe and 14 severe patients on the day they presented (D0), at D14, and six months later, and from 6 non-infected controls. The IL-22R1 expression was characterized by flow cytometry. Results were related to HLA-DR expression of myeloid cells, to plasma concentrations of different cytokines and chemokines and NK cells and T lymphocytes functions characterized by their IFN-γ, IL-22, IL-17A, granzyme B and perforin content. The numbers of IL-22R1⁺ classical, intermediate, and non-classical monocytes and the proportions of IL-22R1⁺ plasmacytoid DC (pDC), myeloid DC1 and DC2 (mDC1, mDC2) were higher in patients than controls at D0. The proportions of IL-22R1⁺ classical and intermediate monocytes, and pDC and mDC2 remained high for six months. High proportions of IL-22R1⁺ non-classical monocytes and mDC2 displayed HLA-DR^high expression and were thus activated. Multivariate analysis for all IL-22R1⁺ myeloid cells discriminated the severity of the disease (AUC=0.9023). However, correlation analysis between IL-22R1⁺ cell subsets and plasma chemokine concentrations suggested pro-inflammatory effects of some subsets and protective effects of others. The numbers of IL-22R1⁺ classical monocytes and pDC were positively correlated with pro-inflammatory chemokines MCP-1 and IP-10 in severe infections, whereas IL-22R1⁺ intermediate monocytes were negatively correlated with IL-6, IFN-α and CRP in non-severe infections. Moreover, in the absence of in vitro stimulation, NK and CD4⁺ T cells produced IFN-γ and IL-22, and CD4⁺ and CD8⁺ T cells produced IL-17A. CD4⁺ T lymphocytes also expressed IL-22R1, the density of its expression defining two different functional subsets. In conclusion, we provide the first evidence that SARS-CoV-2 infection is characterized by an abnormal expression of IL22R1 on blood myeloid cells and CD4⁺ T lymphocytes. Our results suggest that the involvement of the IL-22R1/IL-22 axis could be protective at the beginning of SARS-CoV-2 infection but could shift to a detrimental response over time.

Chronic cerebral aspects of long COVID, post-stroke syndromes and similar states share their pathogenesis and perispinal etanercept treatment logic

The chronic neurological aspects of traumatic brain injury, post-stroke syndromes, long COVID-19, persistent Lyme disease, and influenza encephalopathy having close pathophysiological parallels that warrant being investigated in an integrated manner. A mechanism, common to all, for this persistence of the range of symptoms common to these conditions is described. While TNF maintains cerebral homeostasis, its excessive production through either pathogen-associated molecular patterns or damage-associated molecular patterns activity associates with the persistence of the symptoms common across both infectious and non-infectious conditions. The case is made that this shared chronicity arises from a positive feedback loop causing the persistence of the activation of microglia by the TNF that these cells generate. Lowering this excess TNF is the logical way to reducing this persistent, TNF-maintained, microglial activation. While too large to negotiate the blood-brain barrier effectively, the specific anti-TNF biological, etanercept, shows promise when administered by the perispinal route, which allows it to bypass this obstruction.

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

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

Will Host Genetics Affect the Response to SARS-CoV-2 Vaccines? Historical Precedents

Recent progress in genomics and bioinformatics technologies have allowed for the emergence of immunogenomics field. This intersection of immunology and genetics has broadened our understanding of how the immune system responds to infection and vaccination. While the immunogenetic basis of the huge clinical variability in response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is currently being extensively studied, the host genetic determinants of SARS-CoV-2 vaccines remain largely unknown. Previous reports evidenced that vaccines may not protect all populations or individuals equally, due to multiple host- and vaccine-specific factors. Several studies on vaccine response to measles, rubella, hepatitis B, smallpox, and influenza highlighted the contribution of genetic mutations or polymorphisms in modulating the innate and adaptive immunity following vaccination. Specifically, genetic variants in genes encoding virus receptors, antigen presentation, cytokine production, or related to immune cells activation and differentiation could influence how an individual responds to vaccination. Although such knowledge could be utilized to generate personalized vaccine strategies to optimize the vaccine response, studies in this filed are still scarce. Here, we briefly summarize the scientific literature related to the immunogenetic determinants of vaccine-induced immunity, highlighting the possible role of host genetics in response to SARS-CoV-2 vaccines as well.

The Expansion of Myeloid-Derived Suppressor Cells Correlates With the Severity of Pneumonia in Kidney Transplant Patients

Background

Pneumonia is one of the most frequent but serious infectious complications post kidney transplantation. Severe pneumonia induces sustained immunosuppression, but few parameters concerning immune status are used to assess the severity of pneumonia. Myeloid-derived suppressor cells (MDSCs) are induced under infection and have the strong immunosuppressive capacity, but the correlation between MDSCs and pneumonia in kidney transplant recipients (KTRs) is unknown.

Methods

Peripheral blood MDSCs were longitudinally detected in 58 KTRs diagnosed with pneumonia using flow cytometry and in 29 stable KTRs as a control. The effectors of MDSCs were detected in the plasma. Spearman's rank correlation analysis was performed to determine the correlation between MDSCs and the severity of pneumonia as well as lymphopenia.

Results

The frequency of MDSCs and effectors, including arginase-1, S100A8/A9, and S100A12, were significantly increased in the pneumonia group compared with the stable group. CD11b⁺CD14⁺HLA-DR^low/−CD15⁻ monocytic-MDSCs (M-MDSCs) were higher in the pneumonia group but showed no significant difference between the severe and non-severe pneumonia subgroups. CD11b⁺CD14⁻CD15⁺ low-density granulocytic-MDSCs (G-MDSCs) were specifically increased in the severe pneumonia subgroup and correlated with the severity of pneumonia as well as lymphopenia. During the study period of 2 weeks, the frequencies of MDSCs and G-MDSCs were persistently increased in the severe pneumonia subgroup.

Conclusions

MDSCs and G-MDSCs were persistently increased in KTRs with pneumonia. G-MDSCs were correlated with the severity of pneumonia and could thus be an indicator concerning immune status for assessing pneumonia severity.

Immune mechanisms in cancer patients that lead to poor outcomes of SARS-CoV-2 infection

Patients with cancers have been severely affected by the COVID-19 pandemic. This is highlighted by the adverse outcomes in cancer patients with COVID-19 as well as by the impact of the COVID-19 pandemic on cancer care. Patients with cancer constitute a heterogeneous population that exhibits distinct mechanisms of immune dysfunction, associated with distinct systemic features of hot (T-cell-inflamed/infiltrated) and cold (Non-T-cell-inflamed and/or infiltrated) tumors. The former show hyper immune activated cells and a highly inflammatory environment while, contrastingly, the latter show the profile of a senescent and/or quiescent immune system. Thus, the evolution of SARS-CoV-2 infection in different types of cancers can show distinct trajectories which could lead to a variety of clinical and pathophysiological outcomes. The altered immunological environment including cytokines that characterizes hot and cold tumors will lead to different mechanisms of immune dysfunction, which will result in downstream effects on the course of SARS-CoV-2 infection. This review will focus on defining the known contributions of soluble pro- and anti-inflammatory mediators on immune function including altered T-cells and B-cells responses and as well on how these factors modulate the expression of SARS-CoV-2 receptor ACE2, TMPRSS2 expression, and lymph node fibrosis in cancer patients. We will propose immune mechanisms that underlie the distinct courses of SARS-CoV-2 infection in cancer patients and impact on the success of immune based therapies that have significantly improved cancer outcomes. Better understanding of the immune mechanisms prevalent in cancer patients that are associated to the outcomes of SARS-CoV-2 infection will help to identify the high-risk cancer patients and develop immune-based approaches to prevent significant adverse outcomes by targeting these pathways.