Current Evidence of Interleukin-6 Signaling Inhibitors in Patients With COVID-19: A Systematic Review and Meta-Analysis

A Bird's-Eye View of the Pathophysiologic Role of the Human Urobiota in Health and Disease: Can We Modulate It?

For a long time, urine has been considered sterile in physiological conditions, thanks to the particular structure of the urinary tract and the production of uromodulin or Tamm-Horsfall protein (THP) by it. More recently, thanks to the development and use of new technologies, i.e., next-generation sequencing and expanded urine culture, the identification of a microbial community in the urine, the so-called urobiota, became possible. Major phyla detected in the urine are represented by Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. Particularly, the female urobiota is largely represented by Lactobacillus spp., which are very active against urinary pathogenic Escherichia (E.) coli (UPEC) strains via the generation of lactic acid and hydrogen peroxide. Gut dysbiosis accounts for recurrent urinary tract infections (UTIs), so-called gut-bladder axis syndrome with the formation of intracellular bacterial communities in the course of acute cystitis. However, other chronic urinary tract infections are caused by bacterial strains of intestinal derivation. Monomicrobial and polymicrobial infections account for the outcome of acute and chronic UTIs, even including prostatitis and chronic pelvic pain. E. coli isolates have been shown to be more invasive and resistant to antibiotics. Probiotics, fecal microbial transplantation, phage therapy, antimicrobial peptides, and immune-mediated therapies, even including vaccines for the treatment of UTIs, will be described.

A Prospective Cohort Study of COVID-19: Evaluation of the Early Role of IL-1 and IL-6 Antagonists in Improving the Outcome of the Illness and Reduction in the Risk of Death

The COVID-19 pandemic had a profound impact on global health, economies, and social systems. The crucial factor that determines the success of COVID-19 treatments is preventing the need for mechanical ventilation and intensive care admission. In the context of COVID-19, several treatments have been found to play a role in the disease's progression and severity. Interleukins (ILs) have been identified as key mediators of the cytokine storm that can occur in severe cases of COVID-19, leading to respiratory failure and other complications. For instance, IL-1 antagonist (anakinra) and IL-6 antagonist (tocilizumab) are supposed to be promising treatments as well as cortisones for COVID-19. This prospective study aims to evaluate the effectiveness of anakinra or tocilizumab in addition to cortisone in preventing the progression of mild to moderate COVID-19 cases to severe intensive care admission. Biochemical and hematological parameters, such as D-dimer, ferritin, LDH, CRP, and white blood cells (WBCs), were measured after treatment with either anakinra or tocilizumab in addition to cortisone or cortisone alone. The study also recorded the number of deaths and patients admitted to intensive care. The results indicate that anakinra significantly improved outcomes and decreased the number of intensive care admissions compared to tocilizumab or cortisone alone. Therefore, anakinra may play a vital role in controlling the progression of COVID-19, and its use in mild to moderate cases may prevent the worsening of the disease to severe stages.

Prognostic Value of Serum Interleukin-6 Level in Hypertensive Patients with COVID-19-Associated Pneumonia

Background. An interleukin-6 (IL-6) is a proinflammatory cytokine which plays an important role in COVID-19-associated hyperinflammation. Aim. This study aimed to assess the predictive ability of serum IL-6 levels for the development of severe/critical clinical conditions, a hypoxemic state requiring supplemental oxygen, and lethal outcomes in patients with COVID-19-associated pneumonia and arterial hypertension (AH). Materials and Methods. One hundred and thirty-five unvaccinated patients hospitalized for COVID-19-associated pneumonia were enrolled in the study. AH was diagnosed in 78.5% of cases. Pneumonia was confirmed radiologically. SARS-COV-2 as an etiological factor was confirmed by either PCR or ELISA. In addition to conventional laboratory tests, IL-6, ferritin, and soluble interleukin-2 levels were measured. Results. Among AH patients, the median levels of IL-6 were higher in non-survivors (95.1 [37.8 - 158.8] pg/mL) as compared to survivors (39.5 [13.6 - 81.1] pg/mL) (p=0.04). Among AH patients, the median serum level of IL-6 was 98.3 [37.8 - 158.8] pg/mL in critically ill patients, 41.7 [11.8 - 83.4] pg/mL in severely ill patients, 37.8 [13.6 - 74.4] pg/mL in moderately ill patients (p=0.051). The median serum level of IL-6 was lower at the time of discharge (6.5 [2.0 - 21.5] pg/mL) as compared to that on admission (43.2 [16.1 - 92.0] pg/mL) (p< 0.001). IL-6 level failed to predict severe/critical condition (AUC=0.59, p=0.13) and the need for supplemental oxygen (AUC=0.61, p=0.06); however, it might be used for the prediction of the lethal outcome (AUC=0.69, p=0.03). The cut-off value of IL-6 level for lethal outcome prediction of 91.0 pg/mL showed a sensitivity of 58.3% and a specificity of 78.7%. Patients with IL-6 levels > 91.0 pg/mL on admission had higher odds of lethal outcomes (OR = 4.87 [1.40 - 16.92], p=0.01). Conclusions. Serum IL-6 level on admission did not show significant predictive ability for severe/critical conditions and hypoxemic states requiring supplemental oxygen in AH patients. However, serum IL-6 levels on admission were higher in non-survivors and might be used for the prediction of lethal outcomes with a cut-off value of 91.0 pg/mL in AH patients.

The optimal anticoagulation strategy for COVID-19, prophylactic or therapeutic?: a meta-analysis, trial sequential analysis, and meta-regression of more than 27,000 participants

Background

Anticoagulants are promising regimens for treating coronavirus disease 2019 (COVID-19). However, whether prophylactic or intermediate-to-therapeutic dosage is optimal remains under active discussion.

Methods

We comprehensively searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, ClinicalTrials, and MedRxiv databases on April 26, 2022. Two independent researchers conducted literature selection and data extraction separately according to predetermined criteria. Notably, this is the first meta-analysis on COVID-19, taking serious consideration regarding the dosage overlap between the 2 comparison groups of prophylactic anticoagulation (PA) and intermediate-to-therapeutic anticoagulation (I-TA).

Results

We included 11 randomized controlled trials (RCTs) and 36 cohort studies with 27,051 COVID-19 patients. By analyzing all the RCTs, there was no significant difference in mortality between the PA and I-TA groups, which was further confirmed by trial sequential analysis (TSA) (odds ratio [OR]: 0.93; 95% confidence interval [CI]: 0.71–1.22; P = 0.61; TSA adjusted CI: 0.71–1.26). The rate of major bleeding was remarkably higher in the I-TA group than in the PA group, despite adjusting for TSA (OR: 1.73; 95% CI: 1.15–2.60; P = 0.009; TSA adjusted CI: 1.09–2.58). RCTs have supported the beneficial effect of I-TA in reducing thrombotic events. After including all studies, mortality in the I-TA group was significantly higher than in the PA group (OR: 1.38; 95% CI: 1.15–1.66; P = 0.0005). The rate of major bleeding was similar to the analysis from RCTs (OR: 2.24; 95% CI: 1.86–2.69; P < 0.00001). There was no distinct difference in the rate of thrombotic events between the 2 regimen groups. In addition, in both critical and noncritical subgroups, I-TA failed to reduce mortality but increased major bleeding rate compared with PA, as shown in meta-analysis of all studies, as well as RCTs only. Meta-regression of all studies suggested that there was no relationship between the treatment effect and the overall risk of mortality or major bleeding (P = 0.14, P = 0.09, respectively).

Conclusion

I-TA is not superior to PA for treating COVID-19 because it fails to lower the mortality rate but increases the major bleeding rate in both critical and noncritical patients.

Efficacy of tocilizumab in the treatment of COVID-19: An umbrella review

Tocilizumab is an interleukin (IL)‐6 receptor inhibitor that has been proposed as a therapeutic agent for treating coronavirus disease 2019 (COVID‐19). The aim of this umbrella review was to determine the efficacy of tocilizumab in treating COVID‐19, and to provide an overview of all systematic reviews on this topic. We systematically searched PubMed, Scopus, the Web of Science collection, the Cochrane library, Epistemonikos, and Google Scholar, as well as the medRxiv preprint server. These databases were searched up to 30 September 2021, using the following keywords: ‘SARS‐CoV‐2’, ‘COVID‐19’, ‘tocilizumab’, ‘RHPM‐1’, ‘systematic review’, and ‘meta‐analysis’. Studies were included if they were systematic reviews (with or without meta‐analysis) investigating the efficacy or safety of tocilizumab in confirmed COVID‐19 patients. The AMSTAR 2 checklist was used to assess quality of the included articles, while publication bias was examined using Egger's test. A total of 50 eligible systematic reviews were included. The pooled estimates showed significant reductions in clinical failure (risk ratio (RR) 0.75; 95% confidence interval (CI), 0.61–0.93), deaths (RR 0.78; 95%CI, 0.71–0.85) and the need for mechanical ventilation (RR 0.77; 95%CI, 0.64–0.92) for those receiving tocilizumab compared with the control group. Also, an emerging survival benefit was demonstrated for those who received tocilizumab, over those in the control group (adjusted hazard ratio (aHR) 0.52; 95%CI, 0.43–0.63). In addition, tocilizumab substantially increased the number of ventilator‐free days, compared with the control treatments (weighted mean difference (WMD) 3.38; 95%CI, 0.51–6.25). Furthermore, lymphocyte count (WMD 0.26 × 10⁹/L; 95%CI, 0.14–0.37), IL‐6 (WMD 176.99 pg/mL; 95%CI, 76.34–277.64) and D‐dimer (WMD 741.08 ng/mL; 95%CI, 109.42–1372.75) were all significantly elevated in those receiving tocilizumab. However, the level of lactate dehydrogenase (LDH) (WMD −30.88 U/L; 95%CI, −51.52, −10.24) and C‐reactive protein (CRP) (WMD ‐104.83 mg/L; 95%CI, −133.21, −76.46) were both significantly lower after treatment with tocilizumab. Tocilizumab treatment reduced the risk of intubation, mortality and the length of hospital stay, without increasing the risk of superimposed infections in COVID‐19 patients. Therefore, tocilizumab can be considered an effective therapeutic agent for treating patients with COVID‐19.

Sarilumab Administration in COVID-19 Patients: Literature Review and Considerations

Two years have passed since WHO declared a pandemic state for SARS-CoV-2 infection. COVID-19 pathogenesis consists of a first viral phase responsible for early symptoms followed by an inflammatory phase, cytokine-mediated, responsible for late-onset manifestations up to ARDS. The dysregulated immune response has an outstanding role in the progression of pulmonary damage in COVID-19. IL-6, through the induction of pro-inflammatory chemokines and cytokines, plays a key role in the development and maintenance of inflammation, acting as a pioneer of the hyperinflammatory condition and cytokine storm in severe COVID-19. Therefore, drugs targeting both IL-6 and IL-6 receptors have been evaluated in order to blunt the abnormal SARS-CoV-2-induced cytokine release. Sarilumab, a high-affinity anti-IL-6 receptor antibody, may represent a promising weapon to treat the fearsome hyperinflammatory phase by improving the outcome of patients with moderate-to-severe COVID-19 pneumonia. Further prospective and well-designed clinical studies with larger sample sizes and long-term follow-up are needed to assess the efficacy and the safety of this therapeutic approach to achieve improved outcomes in COVID-19.

Immunotherapy of COVID-19: Inside and Beyond IL-6 Signalling

Acting on the cytokine cascade is key to preventing disease progression and death in hospitalised patients with COVID-19. Among anti-cytokine therapies, interleukin (IL)-6 inhibitors have been the most used and studied since the beginning of the pandemic. Going through previous observational studies, subsequent randomised controlled trials, and meta-analyses, we focused on the baseline characteristics of the patients recruited, identifying the most favourable features in the light of positive or negative study outcomes; taking into account the biological significance and predictivity of IL-6 and other biomarkers according to specific thresholds, we ultimately attempted to delineate precise windows for therapeutic intervention. By stimulating scavenger macrophages and T-cell responsivity, IL-6 seems protective against viral replication during asymptomatic infection; still protective on early tissue damage by modulating the release of granzymes and lymphokines in mild-moderate disease; importantly pathogenic in severe disease by inducing the proinflammatory activation of immune and endothelial cells (through trans-signalling and trans-presentation); and again protective in critical disease by exerting homeostatic roles for tissue repair (through cis-signalling), while IL-1 still drives hyperinflammation. IL-6 inhibitors, particularly anti-IL-6R monoclonal antibodies (e.g., tocilizumab, sarilumab), are effective in severe disease, characterised by baseline IL-6 concentrations ranging from 35 to 90 ng/mL (reached in the circulation within 6 days of hospital admission), a ratio of partial pressure arterial oxygen (PaO2) and fraction of inspired oxygen (FiO2) between 100 and 200 mmHg, requirement of high-flow oxygen or non-invasive ventilation, C-reactive protein levels between 120 and 160 mg/L, ferritin levels between 800 and 1600 ng/mL, D-dimer levels between 750 and 3000 ng/mL, and lactate dehydrogenase levels between 350 and 500 U/L. Granulocyte-macrophage colony-stimulating factor inhibitors might have similar windows of opportunity but different age preferences compared to IL-6 inhibitors (over or under 70 years old, respectively). Janus kinase inhibitors (e.g., baricitinib) may also be effective in moderate disease, whereas IL-1 inhibitors (e.g., anakinra) may also be effective in critical disease. Correct use of biologics based on therapeutic windows is essential for successful outcomes and could inform future new trials with more appropriate recruiting criteria.

An updated overview of recent advances, challenges, and clinical considerations of IL-6 signaling blockade in severe coronavirus disease 2019 (COVID-19)

Since 2019, COVID-19 has become the most important health dilemma around the world. The dysregulated immune response which results in ARDS and cytokine storm has an outstanding role in the progression of pulmonary damage in COVID-19. IL-6, through induction of pro-inflammatory chemokines and cytokines, is the pioneer of the hyperinflammatory condition and cytokine storm in severe COVID-19. Therefore, IL-6 pathway blockade is considered an emerging approach with high efficacy to reduce lung damage in COVID-19. This article aims to review the pleiotropic roles of the IL-6 pathway in lung damage and ARDS in severe COVID-19, and the rationale for IL-6 signaling blockade at different levels, including IL-6 soluble and membrane receptor pathways, IL-6 downstream signaling (such as JAK-STAT) inhibition, and non-specific anti-inflammatory therapeutic approaches. Recent clinical data of each method, with specific concentration on tocilizumab, along with other new drugs, such as sarilumab and siltuximab, have been discussed. Challenges of IL-6 signaling inhibition, such as the risk of superinfection and hepatic injury, and possible solutions have also been explained. Moreover, to achieve the highest efficacy, ongoing clinical trials and special clinical considerations of using different IL-6 inhibitors have been discussed in detail. Special considerations, including the appropriate timing and dosage, monotherapy or combination therapy, and proper side effect managment must be noticed regarding the clinical administration of these drugs. Future studies are still necessary to improve the productivity and unknown aspects of IL-6 signaling blockade for personalized treatment of severe COVID-19.

GM-CSF Promotes Immune Response and Survival in a Mouse Model of COVID-19

COVID-19 results in increased expression of inflammatory cytokines, but inflammation-targeting clinical trials have yielded poor to mixed results. Our studies of other disorders with an inflammatory component, including Alzheimer's disease, chemobrain, Down syndrome, normal aging, and West Nile Virus infection, showed that treatment with the 'pro-inflammatory' cytokine granulocyte-macrophage colony stimulating factor (GM-CSF) in humans or mouse models alleviated clinical, behavioral, and pathological features. We proposed that human recombinant GM-CSF (sargramostim) be repurposed to promote both the innate and adaptive immune responses in COVID-19 to reduce viral load and mortality1. Here, we report the results of a placebo-controlled study of GM-CSF in human ACE2 transgenic mice inoculated intranasally with SARS-CoV2 virus, a model of COVID-19. Infection resulted in high viral titers in lungs and brains and over 85% mortality. GM-CSF treatment beginning one day after infection increased anti-viral antibody titers, lowered mean lung viral titers proportionately (p=0.0020) and increased the odds of long-term survival by up to 5.8-fold (p=0.0358), compared to placebo. These findings suggest that, as an activator of both the innate and adaptive immune systems, GM-CSF/sargramostim may be an effective COVID-19 therapy with the potential to protect from re-infection more effectively than treatment with antiviral drugs or monoclonal antibodies.

Differential Co-Expression Network Analysis Reveals Key Hub-High Traffic Genes as Potential Therapeutic Targets for COVID-19 Pandemic

Background

The recent emergence of COVID-19, rapid worldwide spread, and incomplete knowledge of molecular mechanisms underlying SARS-CoV-2 infection have limited development of therapeutic strategies. Our objective was to systematically investigate molecular regulatory mechanisms of COVID-19, using a combination of high throughput RNA-sequencing-based transcriptomics and systems biology approaches.

Methods

RNA-Seq data from peripheral blood mononuclear cells (PBMCs) of healthy persons, mild and severe 17 COVID-19 patients were analyzed to generate a gene expression matrix. Weighted gene co-expression network analysis (WGCNA) was used to identify co-expression modules in healthy samples as a reference set. For differential co-expression network analysis, module preservation and module-trait relationships approaches were used to identify key modules. Then, protein-protein interaction (PPI) networks, based on co-expressed hub genes, were constructed to identify hub genes/TFs with the highest information transfer (hub-high traffic genes) within candidate modules.

Results

Based on differential co-expression network analysis, connectivity patterns and network density, 72% (15 of 21) of modules identified in healthy samples were altered by SARS-CoV-2 infection. Therefore, SARS-CoV-2 caused systemic perturbations in host biological gene networks. In functional enrichment analysis, among 15 non-preserved modules and two significant highly-correlated modules (identified by MTRs), 9 modules were directly related to the host immune response and COVID-19 immunopathogenesis. Intriguingly, systemic investigation of SARS-CoV-2 infection identified signaling pathways and key genes/proteins associated with COVID-19's main hallmarks, e.g., cytokine storm, respiratory distress syndrome (ARDS), acute lung injury (ALI), lymphopenia, coagulation disorders, thrombosis, and pregnancy complications, as well as comorbidities associated with COVID-19, e.g., asthma, diabetic complications, cardiovascular diseases (CVDs), liver disorders and acute kidney injury (AKI). Topological analysis with betweenness centrality (BC) identified 290 hub-high traffic genes, central in both co-expression and PPI networks. We also identified several transcriptional regulatory factors, including NFKB1, HIF1A, AHR, and TP53, with important immunoregulatory roles in SARS-CoV-2 infection. Moreover, several hub-high traffic genes, including IL6, IL1B, IL10, TNF, SOCS1, SOCS3, ICAM1, PTEN, RHOA, GDI2, SUMO1, CASP1, IRAK3, HSPA5, ADRB2, PRF1, GZMB, OASL, CCL5, HSP90AA1, HSPD1, IFNG, MAPK1, RAB5A, and TNFRSF1A had the highest rates of information transfer in 9 candidate modules and central roles in COVID-19 immunopathogenesis.

Conclusion

This study provides comprehensive information on molecular mechanisms of SARS-CoV-2-host interactions and identifies several hub-high traffic genes as promising therapeutic targets for the COVID-19 pandemic.

Interleukin-6 in SARS-CoV-2 induced disease: Interactions and therapeutic applications

Interleukin-6 (IL-6) is a multi-tasking cytokine that represents high activity in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and cancer. High concentration of this pleiotropic cytokine accounts for hyperinflammation and cytokine storm, and is related to multi-organ failure in patients with SARS-CoV-2 induced disease. IL-6 promotes lymphopenia and increases C-reactive protein (CRP) in such cases. However, blockade of IL-6 is not a full-proof of complete response. Hypoxia, hypoxemia, aberrant angiogenesis and chronic inflammation are inter-related events occurring as a response to the SARS-CoV-2 stimulatory effect on high IL-6 activity. Taking both pro- and anti-inflammatory activities will make complex targeting IL-6 in patient with SARS-CoV-2 induced disease. The aim of this review was to discuss about interactions occurring within the body of patients with SARS-CoV-2 induced disease who are representing high IL-6 levels, and to determine whether IL-6 inhibition therapy is effective for such patients or not. We also address the interactions and targeted therapies in cancer patients who also have SARS-CoV-2 induced disease.

Infection risk with the use of interleukin inhibitors in hospitalized patients with COVID-19: A narrative review

INTRODUCTION

To date, only corticosteroids and interleukin-6 (IL-6) inhibitors have been shown to reduce mortality of hospitalized patients with COVID-19. In this literature review, we aimed to summarize infection risk of IL inhibitors, with or without the use of corticosteroids, used to treat hospitalized patients with COVID-19.

METHODS

A literature search was conducted using the following evidence-based medicine reviews: Cochrane Central Register of Controlled Trials; Cochrane Database of Systematic Reviews; Embase; Ovid Medline; and Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations, Daily and Versions 1946 to April 28, 2021. All relevant articles were identified using the search terms COVID-19 or SARS-coronavirus-2, infections, interleukins, inpatients, adults, and i ncidence.

RESULTS

We identified 36 studies of which 2 were meta-analyses, 5 were randomized controlled trials, 9 were prospective studies, and 20 were retrospective studies. When anakinra was compared with control, 2 studies reported an increased risk of infection, and 3 studies reported a similar or decreased incidence of infection. Canakinumab had a lower associated incidence of infection compared with placebo in one study. When sarilumab was compared with placebo, one study reported an increased risk of infection. Nine studies comparing tocilizumab with placebo reported decreased or no difference in infection risk (odds ratio [OR] for the studies ranged from 0.39-1.21). Fourteen studies comparing tocilizumab with placebo reported an increased risk of infection, ranging from 9.1% to 63.0% (OR for the studies ranged from 1.85-5.04). Infection most commonly presented as bacteremia. Of the 6 studies comparing tocilizumab and corticosteroid use with placebo, 4 reported a nonsignificant increase toward corticosteroids being associated with bacterial infections (OR ranged from 2.76-3.8), and 2 studies reported no increased association with a higher infection risk.

CONCLUSIONS

Our literature review showed mixed results with variable significance for the association of IL-6 inhibitors with risk of infections in patients with COVID-19.

An outlook on antigen-specific adoptive immunotherapy for viral infections with a focus on COVID-19

Although not a standard-of-care yet, adoptive immunotherapeutic approaches have gradually earned a place within the list of antiviral therapies for some of fatal and hard-to-treat viral diseases. To maintain robust antiviral immunity and to effectively target the viral particles and virally-infected cells, immune cells capable of recognizing the viral antigens are required. While conventional vaccination can induce these cells in vivo; another option is to prime and generate antigen-specific immune cells ex vivo. This approach has been successfully trialed for virulent opportunistic viral infections after bone marrow transplantation. Amid the crisis of SARS-CoV2 pandemic, which has been followed by the success of certain early-authorized vaccines; some institutions and companies have explored the effects of viral-specific adoptive cell transfers (ACTs) in trials, as alternative treatments. Aimed at outlining a perspective on antigen-specific adoptive immunotherapy for viral infections, this review article specifically provides an appraisal of ACT-based studies/trials on SARS-CoV2 infection.

New perspective towards therapeutic regimen against SARS-CoV-2 infection

The ongoing enormous loss of human life owing to Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has led to a global crisis ranging from the collapse of health - care systems to socio-economic instability. As SARS-CoV-2 is a novel virus, very little information is available from researchers and therefore, a rigorous effort is required to decode its pathogenicity. There are no licenced treatment options available for treating SARS-CoV-2 infections and the development of a new antiviral drug targeting coronavirus cannot happen soon. Consequently, drug repurposing is a promising solution for combating the present pandemic. In this review, we have thoroughly discussed all the proteins encoded by the SARS-CoV-2 genome; their importance in pathogenicity and their potential role in drug discovery. Also, the budding threat of co-infections by other pathogenic microbes has been highlighted. Furthermore, the advances made in the medicinal field for the treatment and prevention of this viral infection is explained. Altogether, this review will provide some insightful discussions about this infectious disease and will meet certain of the knowledge gaps which exist by presenting an exhaustive and extensive scientific report on the ongoing mission for COVID-19 drug discovery.

Efficacy of tocilizumab in COVID-19: A review of the current evidence

As cases of coronavirus 2019 (COVID-19) keep rising, reported deaths are increasing. Public health measures have been implemented with mixed efficacy. As vaccines are becoming more widely available and accessible globally, treating critically ill COVID-19 patients remains an issue with only dexamethasone found to be therapeutically effective to date. However, trials studying the efficacy of IL-6 inhibitors, namely tocilizumab have been underway with promising results. This paper is a narrative review that aims to review the current evidence provided by randomized clinical trials (RCT) for the use of tocilizumab in COVID-19. Electronic database searches were carried out in Medline, PubMed, Embase, Google Scholar, and ongoing clinical trial registries with the period set from January 1, 2020 to February 20, 2021. Prepublication manuscripts were found using the pre-print repository medRxiv. Keywords included "COVID-19,""coronavirus,""SARS-CoV-2,""sepsis,""pneumonia,""cytokine storm,""cytokine release syndrome,""IL-6 inhibitors," and "tocilizumab," as exact phrases, and a combination of subject headings according to databases syntax. Only trials with a clear and well-defined methodology, at least 100 patients recruited, and which have had results published either after peer review or in pre-print were included. In hospitalized patients with severe COVID-19, who are hypoxic and have a CRP ≥ 75 mg/L, the current evidence favors the use of a combination of tocilizumab and corticosteroids to reduce mortality, among other clinical benefits. There is also overwhelming evidence of the good safety profile of tocilizumab with only few cases of neutropenia reported with a decrease in infection rates. Tocilizumab is currently thought to work through the inhibition of IL-6 receptors (IL-6R), preventing downstream activation of pro-inflammatory reactions and cytokine release syndrome.

Exploiting the obesity-associated immune microenvironment for cancer therapeutics

Obesity causes chronic low-grade inflammation and leads to changes in the immune landscape of multiple organ systems. Given the link between chronic inflammatory conditions and cancer, it is not surprising that obesity is associated with increased risk and worse outcomes in many malignancies. Paradoxically, recent epidemiological studies have shown that high BMI is associated with increased efficacy of immune checkpoint inhibitors (ICI), and a causal relationship has been demonstrated in the preclinical setting. It has been proposed that obesity-associated immune dysregulation underlies this observation by inadvertently creating a favourable microenvironment for increased ICI efficacy. The recent success of ICIs in obese cancer patients raises the possibility that additional immune-targeted therapies may hold therapeutic value in this context. Here we review how obesity affects the immunological composition of the tumor microenvironment in ways that can be exploited for cancer immunotherapies. We discuss existing literature supporting a beneficial role for obesity during ICI therapy in cancer patients, potential opportunities for targeting the innate immune system to mitigate chronic inflammatory processes, and how to pinpoint obese patients who are most likely to benefit from immune interventions without relying solely on body mass index. Given that the incidence of obesity is expanding on an international scale, we propose that understanding obesity-associated inflammation is necessary to reduce cancer mortalities and capitalize on novel therapeutic opportunities in the era of cancer immunotherapy.

Role of IL-6-IL-27 Complex in Host Antiviral Immune Response

The IL family of cytokines participates in immune response and regulation. We previously found that soluble IL-6 receptor plays an important role in the host antiviral response. In this study, we detected the IL-6-IL-27 complex in serum and throat swab samples from patients infected with influenza A virus. A plasmid expressing the IL-6-IL-27 complex was constructed to explore its biological function. The results indicated that the IL-6-IL-27 complex has a stronger antiviral effect than the individual subunits of IL-6, IL-27A, and EBV-induced gene 3. Furthermore, the activity of the IL-6-IL-27 complex is mainly mediated by the IL-27A subunit and the IL-27 receptor α. The IL-6-IL-27 complex can positively regulate virus-triggered expression of IFN and IFN-stimulated genes by interacting with adaptor protein mitochondrial antiviral signaling protein, potentiating the ubiquitination of TNF receptor-associated factors 3 and 6 and NF-κB nuclear translocation. The secreted IL-6-IL-27 complex can induce the phosphorylation of STAT1 and STAT3 and shows antiviral activity. Our results demonstrate a previously unrecognized mechanism by which IL-6, IL-27A, and EBV-induced gene 3 form a large complex both intracellularly and extracellularly, and this complex acts in the host antiviral response.

Immune mediating molecules and pathogenesis of COVID-19-associated neurological disease

Background

Long period of SARS-CoV-2 infection has been associated with psychiatric and cognitive disorders in adolescents and children. SARS-CoV-2 remains dormant in the CNS leading to neurological complications. The wide expression of ACE2 in the brain raises concern for its involvement in SARS-CoV-2 infection. Though, the mechanistic insights about blood-brain barriers (BBB) crossing by SARS-CoV-2 and further brain infection are still not clear. Moreover, the mechanism behind dormant SARS-CoV-2 infections leading to chronic neurological disorders needs to be unveiled. There is an urgent need to find out the risk factor involved in COVID-19-associated neurological disease. Therefore, the role of immune-associated genes in the pathogenesis of COVID-19 associated neurological diseases is presented which could contribute to finding associated genetic risk factors.

Method

The search utilizing multiple databases, specifically, EMBASE, PubMed (Medline), and Google Scholar was performed. Moreover, the literature survey on the involvement of COVID-19, neuropathogenesis, and its consequences was done.

Description

Persistent inflammatory stimuli may promote the progression of neurodegenerative diseases. An increased expression level of cytokine, chemokine, and decreased expression level of immune cells has been associated with the COVID-19 patient. Cytokine storm was observed in severe COVID-19 patients. The nature of SARS-CoV-2 infection can be neuroinflammatory. Genes of immune response could be associated with neurodegenerative diseases.

Conclusion

The present review will provide a useful framework and help in understanding COVID-19-associated neuropathogenesis. Experimental studies on immune-associated genes in COVID-19 patients with neurological manifestations could be helpful to establish its neuropathogenesis.

COVID-19 in immunocompromised populations: implications for prognosis and repurposing of immunotherapies

SARS-CoV-2 is the virus responsible for the COVID-19 pandemic. COVID-19 has highly variable disease severity and a bimodal course characterized by acute respiratory viral infection followed by hyperinflammation in a subset of patients with severe disease. This immune dysregulation is characterized by lymphocytopenia, elevated levels of plasma cytokines and proliferative and exhausted T cells, among other dysfunctional cell types. Immunocompromised persons often fare worse in the context of acute respiratory infections, but preliminary data suggest this may not hold true for COVID-19. In this review, we explore the effect of SARS-CoV-2 infection on mortality in four populations with distinct forms of immunocompromise: (1) persons with hematological malignancies (HM) and hematopoietic stem cell transplant (HCT) recipients; (2) solid organ transplant recipients (SOTRs); (3) persons with rheumatological diseases; and (4) persons living with HIV (PLWH). For each population, key immunological defects are described and how these relate to the immune dysregulation in COVID-19. Next, outcomes including mortality after SARS-CoV-2 infection are described for each population, giving comparisons to the general population of age-matched and comorbidity-matched controls. In these four populations, iatrogenic or disease-related immunosuppression is not clearly associated with poor prognosis in HM, HCT, SOTR, rheumatological diseases, or HIV. However, certain individual immunosuppressants or disease states may be associated with harmful or beneficial effects, including harm from severe CD4 lymphocytopenia in PLWH and possible benefit to the calcineurin inhibitor ciclosporin in SOTRs, or tumor necrosis factor-α inhibitors in persons with rheumatic diseases. Lastly, insights gained from clinical and translational studies are explored as to the relevance for repurposing of immunosuppressive host-directed therapies for the treatment of hyperinflammation in COVID-19 in the general population.

Predicting COVID-19-Comorbidity Pathway Crosstalk-Based Targets and Drugs: Towards Personalized COVID-19 Management

It is well established that pre-existing comorbid conditions such as hypertension, diabetes, obesity, cardiovascular diseases (CVDs), chronic kidney diseases (CKDs), cancers, and chronic obstructive pulmonary disease (COPD) are associated with increased severity and fatality of COVID-19. The increased death from COVID-19 is due to the unavailability of a gold standard therapeutic and, more importantly, the lack of understanding of how the comorbid conditions and COVID-19 interact at the molecular level, so that personalized management strategies can be adopted. Here, using multi-omics data sets and bioinformatics strategy, we identified the pathway crosstalk between COVID-19 and diabetes, hypertension, CVDs, CKDs, and cancers. Further, shared pathways and hub gene-based targets for COVID-19 and its associated specific and combination of comorbid conditions are also predicted towards developing personalized management strategies. The approved drugs for most of these identified targets are also provided towards drug repurposing. Literature supports the involvement of our identified shared pathways in pathogenesis of COVID-19 and development of the specific comorbid condition of interest. Similarly, shared pathways- and hub gene-based targets are also found to have potential implementations in managing COVID-19 patients. However, the identified targets and drugs need further careful evaluation for their repurposing towards personalized treatment of COVID-19 cases having pre-existing specific comorbid conditions we have considered in this analysis. The method applied here may also be helpful in identifying common pathway components and targets in other disease-disease interactions too.

Endothelial cell, myeloid, and adaptive immune responses in SARS-CoV-2 infection

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is an emerging respiratory pathogen that has rapidly spread in human populations. Severe forms of infection associate cytokine release syndrome and acute lung injury due to hyperinflammatory responses even though virus clearance is achieved. Key components of inflammation include immune cell recruitment in infected tissues, a step which is under the control of endothelial cells. Here, we review endothelial cell responses in inflammation and infection due to SARS-CoV-2 together with phenotypic and functional alterations of monocytes, T and B lymphocytes with which they interact. We surmise that endothelial cells function as an integrative and active platform for the various cells recruited, where fine tuning of immune responses takes place and which provides opportunities for therapeutic intervention.

Coronavirus disease 2019 (COVID-19) and autoimmunity

The coronavirus 2019 pandemic (coronavirus disease, COVID-19), etiologically related to the SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus-2), has once again reawakened healthcare professionals’ interest towards new clinical and conceptual issues of human immunology and immunopathology. An unprecedented number of clinical trials and fundamental studies of epidemiology, virology, immunology and molecular biology, of the COVID-19 clinical course polymorphism and pharmacotherapy have been conducted within one year since the outbreak of 2019 pandemic, bringing together scientists of almost all biological and physicians of almost all medical specialties. Their joint efforts have resulted in elaboration of several types of vaccines against SARS-CoV-2 infection and, in general, fashioning of more rational approaches to patient management. Also important for COVID-19 management were all clinical trials of biologics and “targeted” anti-inflammatory drugs modulating intracellular cytokine signaling, which have been specifically developed for treatment immune-mediated inflammatory rheumatic disease (IMIRDs) over the past 20 years. It became obvious after a comprehensive analysis of the entire spectrum of clinical manifestations and immunopathological disorders in COVID-19 is accompanied by a wide range of extrapulmonary clinical and laboratory disorders, some of which are characteristic of IMIRDs and other autoimmune and auto-in-flammatory human diseases. All these phenomena substantiated the practice of anti-inflammatory drugs repurposing with off-label use of specific antirheumatic agents for treatment of COVID-19. This paper discusses potential use of glucocorticoids, biologics, JAK inhibitors, etc., blocking the effects of pro-inflammatory cytokines for treatment of COVID-19.

Is COVID-19 an Independent Risk Factor for Heparin-Induced Thrombocytopenia?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a viral respiratory illness initially described in Wuhan, China, and was declared a pandemic by World Health Organization (WHO) in 2020, and the disease is named coronavirus disease (COVID-19). SARS-CoV2 is known to cause fever, cough, fatigue, and acute respiratory distress syndrome. As more patients become infected, extrapulmonary manifestations came to rise and hypercoagulability is one among those. COVID-19 could predispose patients to both venous and arterial thromboembolic events which are commonly treated with unfractionated heparin or low molecular weight heparin (LMWH). The treatment of patients who develop heparin-induced thrombocytopenia (HIT) while being treated with heparin or LMWH for COVID-induced thromboembolic complications is challenging.

We describe a patient admitted to the hospital with COVID-19 pneumonia, found to have a cerebrovascular event treated with unfractionated heparin. She also received therapeutic LMWH for anticoagulation on day 1 of presentation due to atrial fibrillation. She was diagnosed with HIT and was found to have a pulmonary embolism, aortic arch mural thrombus, and arterial thrombi in the lower extremities. As more recent studies showed HIT antibodies in COVID-19 patients who are naive for heparin-based products, COVID-19 may be an independent risk factor for the development of HIT. The role of COVID-19 in the development of HIT is uncertain. High vigilance is required to diagnose and initiate treatment for HIT early in the disease course as it can be life-threatening.