COVID-19 and cytokine storm syndrome: are there lessons from macrophage activation syndrome?

Liver type 1 innate lymphoid cells undergo apoptosis in murine models of macrophage activation syndrome and are dispensable for disease

Macrophage activation syndrome (MAS) exemplifies a severe cytokine storm disorder with liver inflammation. In the liver, classical natural killer (cNK) cells and liver-resident type 1 innate lymphoid cells (ILC1s) dominate the ILC population. Thus far, research has primarily focused on the corresponding role of cNK cells. Considering the liver inflammation and cytokine storm in MAS, liver-resident ILC1s represent an interesting population to explore due to their rapid cytokine production upon environmental triggers. By utilizing a Toll-like receptor (TLR)9- and TLR3:4-triggered MAS model, we showed that ILC1s highly produce IFN-γ and TNF-α. However, activated ILC1s undergo apoptosis and are strongly reduced in numbers, while cNK cells resist inflammation-induced apoptosis. Signs of mitochondrial stress suggest that this ILC1 apoptosis may be driven by inflammation-induced mitochondrial impairment. To study whether early induction of highly cytokine-producing ILC1s influences MAS development, we used Hobit KO mice due to their paucity of liver ILC1s but unaffected cNK cell numbers. Nevertheless, neither the severity of MAS features nor the total inflammatory cytokine levels were affected in these Hobit KO mice, indicating that ILC1s are dispensable for MAS pathogenesis. Collectively, our data demonstrate that ILC1s undergo apoptosis during TLR-triggering and are dispensable for MAS pathogenesis.

In Vitro Safety Study on the Use of Cold Atmospheric Plasma in the Upper Respiratory Tract

Cold atmospheric plasma (CAP) devices generate reactive oxygen and nitrogen species, have antimicrobial and antiviral properties, but also affect the molecular and cellular mechanisms of eukaryotic cells. The aim of this study is to investigate CAP treatment in the upper respiratory tract (URT) to reduce the incidence of ventilator-associated bacterial pneumonia (especially superinfections with multi-resistant pathogens) or viral infections (e.g., COVID-19). For this purpose, the surface-microdischarge-based plasma intensive care (PIC) device was developed by terraplasma medical GmbH. This study analyzes the safety aspects using in vitro assays and molecular characterization of human oral keratinocytes (hOK), human bronchial-tracheal epithelial cells (hBTE), and human lung fibroblasts (hLF). A 5 min CAP treatment with the PIC device at the "throat" and "subglottis" positions in the URT model did not show any significant differences from the untreated control (ctrl.) and the corresponding pressurized air (PA) treatment in terms of cell morphology, viability, apoptosis, DNA damage, and migration. However, pro-inflammatory cytokines (MCP-1, IL-6, and TNFα) were induced in hBTE and hOK cells and profibrotic molecules (collagen-I, FKBP10, and αSMA) in hLF at the mRNA level. The use of CAP in the oropharynx may make an important contribution to the recovery of intensive care patients. The results indicate that a 5 min CAP treatment in the URT with the PIC device does not cause any cell damage. The extent to which immune cell activation is induced and whether it has long-term effects on the organism need to be carefully examined in follow-up studies in vivo.

Identification of biomarkers for COVID-19 associated secondary hemophagocytic lymphohistiocytosis

OBJECTIVES

We aimed to define and validate novel biomarkers that could identify individuals with COVID-19 associated secondary hemophagocytic lymphohistiocytosis (sHLH) and to test whether fatalities due to COVID-19 in the presence of sHLH were associated with specific defects in the immune system.

DESIGN

In two cohorts of adult patients presenting with COVID-19 in 2020 and 2021, clinical lab values and serum proteomics were assessed. Subjects identified as having sHLH were compared to those with COVID-19 without sHLH. Eight deceased patients defined as COVID-sHLH underwent genomic sequencing in order to identify variants in immune-related genes.

SETTING

Two tertiary care hospitals in Seattle, Washington (Virginia Mason Medical Center and Harborview Medical Center).

PATIENTS

186 patients with COVID-19.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Nine percent of enrolled COVID-19 subjects met our defined criteria for sHLH. Using broad serum proteomic approaches (O-link and SomaScan), we identified three biomarkers for COVID-19 associated sHLH (soluble PD-L1, TNF-R1, and IL-18BP), supporting a role for proteins previously associated with other forms of sHLH (IL-18BP and sTNF-R1). We also identified novel biomarkers and pathways of COVID-sHLH, including sPD-L1 and the syntaxin pathway. We detected variants in several genes involved in immune responses in individuals with COVID-sHLH, including in DOCK8 and in TMPRSS15, suggesting that genetic alterations in immune-related genes may contribute to hyperinflammation and fatal outcomes in COVID-19.

CONCLUSIONS

Biomarkers of COVID-19 associated sHLH, such as soluble PD-L1, and pathways, such as the syntaxin pathway, and variants in immune genes in these individuals, suggest critical roles for the immune response in driving sHLH in the context of COVID-19.

Knee osteonecrosis after SARS-CoV-2 infection: a systematic case-based review

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for coronavirus disease 2019 (COVID-19). Patients with COVID-19 manifested symptoms mainly related to the respiratory system, but also the musculoskeletal system can be involved. COVID-19 has been described as a possible cause of knee osteonecrosis (ON). A systematic review was performed to investigate the hypothetical correlation between COVID-19 and knee ON.

Methods

Inclusion criteria were all articles reporting cases of knee ON after a diagnosis of SARS-CoV-2 infection. Considering that COVID-19 is an emerging disease, all levels of evidence studies were included.

Results

Finally, two case series and three case reports were included. We extracted data regarding demographic and clinical characteristics, details of magnetic resonance imaging (MRI), use of corticosteroids (CCS), temporal correlation between ON and COVID-19, treatment of the lesion and its outcomes. A total of seven cases of post-COVID knee ON have been described. Knee pain arose on average 11 weeks after the diagnosis of COVID-19. All patients had knee MRI showing ON. CCS were used to treat COVID-19-related symptoms in four cases. Conservative treatment was successful in five patients.

Conclusions

The correlation between COVID-19 and ON remains unclear. Probably post-COVID-19 ON has a multifactorial origin in which factors related to the patient, consequences of COVID-19 and CCS therapy add up to cause a reduction of blood supply and bone vitality until ON is triggered. A greater number of patients is needed to clarify the role of COVID-19 in the etiopathogenesis of knee ON.

Frontiers and hotspots evolution in cytokine storm: A bibliometric analysis from 2004 to 2022

Background

As a fatal disease, cytokine storm has garnered research attention in recent years. Nonetheless, as the body of related studies expands, a thorough and impartial evaluation of the current status of research on cytokine storms remains absent. Consequently, this study aimed to thoroughly explore the research landscape and evolution of cytokine storm utilizing bibliometric and knowledge graph approaches.

Methods

Research articles and reviews centered on cytokine storms were retrieved from the Web of Science Core Collection database. For bibliometric analysis, tools such as Excel 365, CiteSpace, VOSviewer, and the Bibliometrix R package were utilized.

Results

This bibliometric analysis encompassed 6647 articles published between 2004 and 2022. The quantity of pertinent articles and citation frequency exhibited a yearly upward trend, with a sharp increase starting in 2020. Network analysis of collaborations reveals that the United States holds a dominant position in this area, boasting the largest publication count and leading institutions. Frontiers in Immunology ranks as the leading journal for the largest publication count in this area. Stephan A. Grupp, a prominent researcher in this area, has authored the largest publication count and has the second-highest citation frequency. Research trends and keyword evaluations show that the connection between cytokine storm and COVID-19, as well as cytokine storm treatment, are hot topics in research. Furthermore, research on cytokine storm and COVID-19 sits at the forefront in this area.

Conclusion

This study employed bibliometric analysis to create a visual representation of cytokine storm research, revealing current trends and burgeoning topics in this area for the first time. It will provide valuable insights, helping scholars pinpoint critical research areas and potential collaborators.

Evaluation of some immunological markers in co-infection of COVID-19 with thrush candidiasis

OBJECTIVE

COVID-19 infection poses significant risks, including life-threatening consequences and fungus synchronization, making it a significant concern. This study seeks to assess the effect of concurrent infection of COVID-19 with Thrush Candida albicans on the patient's health state by measuring the proportion of immune cells and certain interleukins such as IL-8, -10, -17, and -33.

METHODS

The study involved 70 patients (30 patients with COVID-19, 17 patients with thrush candidiasis, and 23 patients with Thrush Candida albicans) and 50 healthy individuals as a control group. COVID-19 was identified using RT-PCR, while C. albicans were identified through culture media, biochemical testing, and oral swabs. Ruby equipment and ELISA kits were used for blood counts and interleukin detection.

RESULTS

COVID-19, thrush candidiasis, and Thrush Candida albicans infections occur in a wide range of age groups (4-80 years), with no significant differences between sexes (p>0.05). Immunologically, our study found that Thrush Candida albicans patients had the highest rate of neutrophils (89.6%) and basophils (2.01%), while corona patients had the highest percentage of lymphocytes (70.12%) and eosinophils (7.11%), and patients with thrush candidiasis had the highest percentage of monocytes. Thrush Candida albicans patients showed increased IL-8 (56.7 pg/mL) and IL-17 (101.1 pg/mL) concentrations, with the greatest concentration of IL-33 (200.5 pg/mL) in COVID-19, and a decrease in the level of IL-10 in patient groups compared with controls.

CONCLUSION

Patient groups showed increased neutrophils, lymphocytes, monocytes, and IL-8 levels, with a significant linear association between proinflammatory interleukins and these cells.

Sulfasalazine-induced drug reaction with eosinophilia and systemic symptoms (DRESS) coinfected with COVID-19 complicated by hemophagocytic lymphohistiocytosis: a case report

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) is characterized by a widespread maculopapular rash, lymphadenopathy, fever, and multisystem involvement. Conversely, hemophagocytic lymphohistiocytosis (HLH) is an infrequent yet critical condition presenting with fever, hepatosplenomegaly, cytopenias, coagulation abnormalities, and elevated inflammatory markers. The overlapping clinical and laboratory features between DRESS and HLH poses a significant diagnostic challenge. Secondary HLH (sHLH) typically occurs in adults triggered by viral infections, malignancies, rheumatologic diseases, or immune deficiencies. Recently, COVID-19 has also been identified as one of the triggers for sHLH. Herein, we present a case of Sulfasalazine-induced DRESS coinfected with COVID-19 that subsequently progressed into HLH. Our patient exhibited common hepatorenal and splenic involvement along with rare cholecystitis and appendicitis. However, a significant improvement was observed upon the addition of etoposide and azathioprine. We hypothesize that excessive activation of the immune system and cytokine storm due to DRESS combined with COVID-19 infection led to more extensive systemic damage resulting in HLH development. This highlights the potential for severe consequences when DRESS coincides with HLH during a COVID-19 infection.

The association between high mobility group box 1 (HMGB1) and Interleukin-18 (IL-18) serum concentrations in COVID-19 inpatients

Background

High mobility group box 1 (HMGB1) and interleukin-18 (IL-18) are involved in various non-coronavirus disease pathogenesis and are reported as potential biomarkers for coronavirus disease (COVID-19). However, their association with COVID-19 pathogenesis has not yet been explored.

Aim

This study aimed to investigate the association between HMGB1 and IL-18 concentrations in the sera of COVID-19 patients versus non-COVID-19 patients.

Material and methods

We used stored serum samples obtained from 30 COVID-19 patients and 30 non-COVID-19 patients. We collected data on age, gender, treatment status, principal diagnosis, and comorbidity from patient medical records. HMGB1 and IL-18 concentrations were analyzed in the serum by enzyme-linked immunosorbent assay (ELISA). The swab samples' RT-PCR cycle threshold (CT) values were obtained from the laboratory database.

Results

HMGB1 concentrations were increased in the COVID-19 inpatients and non-COVID-19 inpatients compared to non-COVID-19 outpatients (COVID-19 inpatients vs. non-COVID-19 outpatients: 151.33 (90.27-192.38) vs. 80.75 (54.16-128.72) ng/ml; p = 0.0316; non-COVID-19 inpatients vs. non-COVID-19 outpatients: 152.66 (104.04-288.51) vs. 80.75 (54.16-128.72) ng/ml; p = 0.0199). IL-18 concentrations were also higher in the COVID-19 inpatients and non-COVID-19 inpatients compared to non-COVID-19 outpatients (COVID-19 inpatients vs. non-COVID-19 outpatients: 620.00 (461.50-849.6) vs. 403.10 (372.70-556.90) pg/ml; p = 0.0376; non-COVID-19 inpatients vs. non-COVID-19 outpatients: 835.70 (558.30-1602.00) vs. 403.10 (372.70-556.90) pg/ml; p = 0.0026). Moreover, HMGB1 was associated with IL-18 concentrations in the sera of COVID-19 inpatients (p = 0.0337; r = 0.5500).

Conclusion

The association of HMGB1 and IL-18 in COVID-19 might indicate the potential for a dangerous cycle leading to a cytokine storm to occur.

Criteria for Cytokine Storm Syndromes

In the past two decades, there has been a great deal of work aimed to devise diagnostic guidelines, classification criteria, and diagnostic scores for cytokine storm syndromes (CSSs). The most notable effort has been the large-scale multinational study that led to the development of the 2016 classification criteria for macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (JIA). Future studies should scrutinize the validity of the proposed criteria, particularly in systemic JIA patients treated with biologics, in children with subtle or incomplete forms of MAS, and in patients with MAS complicating other rheumatologic disorders. More generic CSS criteria are also available but often lack sensitivity and specificity in a wide variety of patient populations and CSSs of different etiologies. The coronavirus disease 2019 (COVID-19)-related lung disease led to an evolution of the concept of a "cytokine storm." Emerging and unsolved challenges in the diagnosis of the different forms of CSSs highlight the need for diagnostic tools and well-established classification criteria to enable timely recognition and correct classification of patients.

Adjunctive use of oral MAF is associated with no disease progression or mortality in hospitalized patients with COVID-19 pneumonia: The single-arm COral-MAF1 prospective trial

Based on a growing body of evidence that a dysregulated innate immune response mediated by monocytes/macrophages plays a key role in the pathogenesis of COVID-19, a clinical trial was conducted to investigate the therapeutic potential and safety of oral macrophage activating factor (MAF) plus standard of care (SoC) in the treatment of hospitalized patients with COVID-19 pneumonia. Ninety-seven hospitalized patients with confirmed COVID-19 pneumonia were treated with oral MAF and a vitamin D3 supplement, in combination with SoC, in a single-arm, open label, multicentre, phase II clinical trial. The primary outcome measure was a reduction in an intensive care unit transfer rate below 13% after MAF administration. At the end of the study, an additional propensity score matching (PSM) analysis was performed to compare the MAF group with a control group treated with SoC alone. Out of 97 patients treated with MAF, none needed care in the ICU and/or intubation with mechanical ventilation or died during hospitalization. Oxygen therapy was discontinued after a median of nine days of MAF treatment. The median length of viral shedding and hospital stay was 14 days and 18 days, respectively. After PSM, statistically significant differences were found in all of the in-hospital outcomes between the two groups. No mild to serious adverse events were recorded during the study. Notwithstanding the limitations of a single-arm study, which prevented definitive conclusions, a 21-day course of MAF treatment plus SoC was found to be safe and promising in the treatment of hospitalized adult patients with COVID-19 pneumonia. Further research will be needed to confirm these preliminary findings.

MTOR gene variants are associated with severe COVID-19 outcomes: A multicenter study

BACKGROUND

The worst outcomes linked to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been attributed to the cytokine storm, which contributes significantly to the immunopathogenesis of the disease. The mammalian target of rapamycin (mTOR) pathway is essential for orchestrating innate immune cell defense including cytokine production and is dysregulated in severe Coronavirus Disease 2019 (COVID-19) individuals. The individual genetic background might play a role in the exacerbated immune response.

OBJECTIVE

In this study, we aimed to investigate the association between MTOR genetic variants and COVID-19 outcomes.

METHODS

This study enrolled groups of individuals with severe (n = 285) and mild (n = 207) COVID-19 from Brazilian states. The MTOR variants, rs1057079 and rs2536, were genotyped. A logistic regression analysis and Kaplan-Meier survival curves were performed. We applied a genotyping risk score to estimate the cumulative contribution of the risk alleles. Tumor necrosis factor (TNF) and interleukin-6 (IL-6) plasma levels were also measured.

RESULTS

The T allele of the MTOR rs1057079 variant was associated with a higher likelihood of developing the most severe form of COVID-19. In addition, higher levels of IL-6 and COVID-19 death was linked to the T allele of the rs2536 variant. These variants exhibited a cumulative risk when inherited collectively.

CONCLUSIONS

These results show a potential pathogenetic role of MTOR gene variants and may be useful for predicting severe outcomes following COVID-19 infection, resulting in a more effective allocation of health resources.

Advances in attractive therapeutic approach for macrophage activation syndrome in COVID-19

Nowadays, people have relaxed their vigilance against COVID-19 due to its declining infection numbers and attenuated virulence. However, COVID-19 still needs to be concern due to its emerging variants, the relaxation of restrictions as well as breakthrough infections. During the period of the COVID-19 infection, the imbalanced and hyper-responsive immune system plays a critical role in its pathogenesis. Macrophage Activation Syndrome (MAS) is a fatal complication of immune system disease, which is caused by the excessive activation and proliferation of macrophages and cytotoxic T cells (CTL). COVID-19-related hyperinflammation shares common clinical features with the above MAS symptoms, such as hypercytokinemia, hyperferritinemia, and coagulopathy. In MAS, immune exhaustion or defective anti-viral responses leads to the inadequate cytolytic capacity of CTL which contributes to prolonged interaction between CTL, APCs and macrophages. It is possible that the same process also occurred in COVID-19 patients, and further led to a cytokine storm confined to the lungs. It is associated with the poor prognosis of severe patients such as multiple organ failure and even death. The main difference of cytokine storm is that in COVID-19 pneumonia is mainly the specific damage of the lung, while in MAS is easy to develop into a systemic. The attractive therapeutic approach to prevent MAS in COVID-19 mainly includes antiviral, antibiotics, convalescent plasma (CP) therapy and hemadsorption, extensive immunosuppressive agents, and cytokine-targeted therapies. Here, we discuss the role of the therapeutic approaches mentioned above in the two diseases. And we found that the treatment effect of the same therapeutic approach is different.

Innate and adaptive immunity to SARS-CoV-2 and predisposing factors

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), has affected all countries worldwide. Although some symptoms are relatively mild, others are still associated with severe and even fatal clinical outcomes. Innate and adaptive immunity are important for the control of SARS-CoV-2 infections, whereas a comprehensive characterization of the innate and adaptive immune response to COVID-19 is still lacking and the mechanisms underlying immune pathogenesis and host predisposing factors are still a matter of scientific debate. Here, the specific functions and kinetics of innate and adaptive immunity involved in SARS-CoV-2 recognition and resultant pathogenesis are discussed, as well as their immune memory for vaccinations, viral-mediated immune evasion, and the current and future immunotherapeutic agents. We also highlight host factors that contribute to infection, which may deepen the understanding of viral pathogenesis and help identify targeted therapies that attenuate severe disease and infection.

Transcriptional Insights of Oxidative Stress and Extracellular Traps in Lung Tissues of Fatal COVID-19 Cases

Neutrophil extracellular traps (NETs) and oxidative stress are considered to be beneficial in the innate immune defense against pathogens. However, defective clearance of NETs in the lung of acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients could lead to severe respiratory syndrome infection, the so-called coronavirus disease 2019 (COVID-19). To elucidate the pathways that are related to NETs within the pathophysiology of COVID-19, we utilized RNA sequencing (RNA-seq) as well as immunofluorescence and immunohistochemistry methods. RNA-seq analysis provided evidence for increased oxidative stress and the activation of viral-related signaling pathways in post-mortem lungs of COVID-19 patients compared to control donors. Moreover, an excess of neutrophil infiltration and NET formation were detected in the patients' lungs, where the extracellular DNA was oxidized and co-localized with neutrophil granule protein myeloperoxidase (MPO). Interestingly, staining of the lipid peroxidation marker 4-hydroxynonenal (4-HNE) depicted high colocalization with NETs and was correlated with the neutrophil infiltration of the lung tissues, suggesting that it could serve as a suitable marker for the identification of NETs and the severity of the disease. Moreover, local inhalation therapy to reduce the excess lipid oxidation and NETs in the lungs of severely infected patients might be useful to ameliorate their clinical conditions.

Blood filtering system for COVID-19 management: novel modality of the cytokine storm therapeutics

The newly emerged coronavirus (SARS-CoV-2) is virulent, contagious, and has rapidly gained many mutations, which makes it highly infectious and swiftly transmissible around the world. SARS-CoV-2 infects people of all ages and targets all body organs and their cellular compartments, starting from the respiratory system, where it shows many deleterious effects, to other tissues and organs. Systemic infection can lead to severe cases that require intensive intervention. Multiple approaches were elaborated, approved, and successfully used in the intervention of the SARS-CoV-2 infection. These approaches range from the utilization of single and/or mixed medications to specialized supportive devices. For critically ill COVID-19 patients with acute respiratory distress syndrome, both extracorporeal membrane oxygenation (ECMO) and hemadsorption are utilized in combination or individually to support and release the etiological factors responsible for the "cytokine storm" underlying this condition. The current report discusses hemadsorption devices that can be used as part of supportive treatment for the COVID-19-associated cytokine storm.

Transcription factor Nrf2 as a potential therapeutic target for COVID-19

The coronavirus disease 2019 (COVID-19) is caused by a novel severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2). Critically ill patients with SARS-COV-2 infection frequently exhibit signs of high oxidative stress and systemic inflammation, which accounts for most of the mortality. Antiviral strategies to inhibit the pathogenic consequences of COVID-19 are urgently required. The nuclear factor erythroid 2-related transcription factor (Nrf2) is a transcription factor that is involved in antioxidant and anti-inflammatory defense in several tissues and cells. This review tries to present an overview of the role of Nrf2 in the treatment of COVID-19.

Case report: Multisystem inflammatory syndrome in children associated with COVID-19, macrophage activation syndrome, and incomplete Kawasaki disease

Background

Multisystem inflammatory syndrome in children (MIS-C), is a severe complication of coronavirus disease 2019 (COVID-19), characterized by persistent fever, systemic inflammatory response, and organ failure. MIS-C with a history of COVID-19 may share clinical features with other well-defined syndromes such as macrophage activation syndrome, Kawasaki disease, hemophagocytic syndrome and toxic shock syndrome.

Case 1

An 11-year-old male with a history of hypothyroidism and precocious puberty with positive antibody test for COVID-19 was admitted for fever, poor general condition, severe respiratory distress, refractory shock, and multiple organ failure. His laboratory examination showed elevated inflammatory parameters, and bone marrow aspirate showed hemophagocytosis.

Case 2

A 13-year-old male with a history of attention deficit hyperactivity disorder and cognitive delay presented clinical manifestations of Kawasaki disease, fever, conjunctival congestion, exanthema, and hyperemia in oral mucosa, tongue, and genitals, with refractory shock and multiple organ failure. Reverse transcriptase polymerase chain reaction (RT-PCR) and antibodies for COVID-19 were negative, inflammation parameters were elevated, and bone marrow aspirate showed hemophagocytosis. Patients required intensive care with invasive mechanical ventilation, vasopressor support, intravenous gamma globulin, systemic corticosteroids, low molecular weight heparin, antibiotics, and monoclonal antibodies and, patient 2 required renal replacement therapy.

Conclusions

Multisystemic inflammatory syndrome in children can have atypical manifestations, and identifying them early is very important for the timely treatment and prognosis of patients.

Biomarkers of cell damage, neutrophil and macrophage activation associated with in-hospital mortality in geriatric COVID-19 patients

BACKGROUND

The risk for symptomatic COVID-19 requiring hospitalization is higher in the older population. The course of the disease in hospitalised older patients may show significant variation, from mild to severe illness, ultimately leading to death in the most critical cases. The analysis of circulating biomolecules involved in mechanisms of inflammation, cell damage and innate immunity could lead to identify new biomarkers of COVID-19 severity, aimed to improve the clinical management of subjects at higher risk of severe outcomes. In a cohort of COVID-19 geriatric patients (n= 156) who required hospitalization we analysed, on-admission, a series of circulating biomarkers related to neutrophil activation (neutrophil elastase, LL-37), macrophage activation (sCD163) and cell damage (nuclear cfDNA, mithocondrial cfDNA and nuclear cfDNA integrity). The above reported biomarkers were tested for their association with in-hospital mortality and with clinical, inflammatory and routine hematological parameters. Aim of the study was to unravel prognostic parameters for risk stratification of COVID-19 patients.

RESULTS

Lower n-cfDNA integrity, higher neutrophil elastase and higher sCD163 levels were significantly associated with an increased risk of in-hospital decease. Median (IQR) values observed in discharged vs. deceased patients were: 0.50 (0.30-0.72) vs. 0.33 (0.22-0.62) for n-cfDNA integrity; 94.0 (47.7-154.0) ng/ml vs. 115.7 (84.2-212.7) ng/ml for neutrophil elastase; 614.0 (370.0-821.0) ng/ml vs. 787.0 (560.0-1304.0) ng/ml for sCD163. The analysis of survival curves in patients stratified for tertiles of each biomarker showed that patients with n-cfDNA integrity < 0.32 or sCD163 in the range 492-811 ng/ml had higher risk of in-hospital decease than, respectively, patients with higher n-cfDNA integrity or lower sCD163. These associations were further confirmed in multivariate models adjusted for age, sex and outcome-related clinical variables. In these models also high levels of neutrophil elastase (>150 ng/ml) appeared to be independent predictor of in-hospital death. An additional analysis of neutrophil elastase in patients stratified for n-cfDNA integrity levels was conducted to better describe the association of the studied parameters with the outcome.

CONCLUSIONS

On the whole, biomarkers of cell-free DNA integrity, neutrophil and macrophage activation might provide a valuable contribution to identify geriatric patients with high risk of COVID-19 in-hospital mortality.

Criteria for Hyperinflammation Developing in COVID-19: Analysis of 2 Cohorts From Different Periods of the Pandemic

OBJECTIVE

Hyperinflammation (HI) that develops in week 2 of COVID-19 contributes to a worse outcome. Because week 2 laboratory findings can be relatively mild, the available criteria for classification of hemophagocytic lymphohistiocytosis or macrophage activation syndrome are not helpful.

METHODS

Our study included a discovery cohort of patients from Turkey with symptomatic COVID-19 who were followed up while hospitalized during the initial wave and a replication cohort of hospitalized patients from a later period, all of whom required oxygen support and received glucocorticoids. Diagnosis of HI was made by an expert panel; most patients with COVID-19-associated HI (HIC) received tocilizumab or anakinra. Clinical and laboratory data from start day of treatment with tocilizumab or anakinra in HIC patients were compared with the data from day 5-6 in patients without HIC. Values maximizing the sensitivity and specificity of each parameter were calculated to determine criteria items.

RESULTS

The discovery cohort included 685 patients, and the replication cohort included 156 patients, with 150 and 61 patients receiving treatment for HI, respectively. Mortality rate in HI patients in the discovery cohort (23.3%) was higher than the rate in patients without HI (3.7%) and the rate in patients in the overall replication cohort (10.3%). The 12-item criteria that we developed for HIC showed that a score of 35 provided 85.3% sensitivity and 81.7% specificity for identification of HIC. In the replication cohort, the same criteria resulted in 90.0% sensitivity for HIC; however, lower specificity values were observed because of the inclusion of milder cases of HIC responding only to glucocorticoids.

CONCLUSION

The use of the 12-item criteria for HIC can better define patients with HIC with reasonable sensitivity and specificity and enables an earlier treatment start.

Nutritional parameters associated with prognosis in non-critically ill hospitalized COVID-19 patients: The NUTRI-COVID19 study

BACKGROUND & AIMS

To investigate the association between the parameters used in nutritional screening assessment (body mass index [BMI], unintentional weight loss [WL] and reduced food intake) and clinical outcomes in non-critically ill, hospitalized coronavirus disease 2019 (COVID-19) patients.

METHODS

This was a prospective multicenter real-life study carried out during the first pandemic wave in 11 Italian Hospitals. In total, 1391 patients were included. The primary end-point was a composite of in-hospital mortality or admission to ICU, whichever came first. The key secondary end-point was in-hospital mortality.

RESULTS

Multivariable models were based on 1183 patients with complete data. Reduced self-reported food intake before hospitalization and/or expected by physicians in the next days since admission was found to have a negative prognostic impact for both the primary and secondary end-point (P < .001 for both). No association with BMI and WL was observed. Other predictors of outcomes were age and presence of multiple comorbidities. A significant interaction between obesity and multi-morbidity (≥2) was detected. Obesity was found to be a risk factor for composite end-point (HR = 1.36 [95%CI, 1.03-1.80]; P = .031) and a protective factor against in-hospital mortality (HR = 0.32 [95%CI, 0.20-0.51]; P < .001) in patients with and without multiple comorbidities, respectively. Secondary analysis (patients, N = 829), further adjusted for high C-reactive protein (>21 mg/dL) and LDH (>430 mU/mL) levels yielded consistent findings.

CONCLUSIONS

Reduced self-reported food intake before hospitalization and/or expected by physicians in the next days since admission was associated with negative clinical outcomes in non-critically ill, hospitalized COVID-19 patients. This simple and easily obtainable parameter may be useful to identify patients at highest risk of poor prognosis, who may benefit from prompt nutritional support. The presence of comorbidities could be the key factor, which may determine the protective or harmful role of a high body mass index in COVID-19.

The SARS-CoV-2 S1 Spike Protein Promotes MAPK and NF-kB Activation in Human Lung Cells and Inflammatory Cytokine Production in Human Lung and Intestinal Epithelial Cells

The coronavirus disease 2019 (COVID-19) pandemic began in January 2020 in Wuhan, China, with a new coronavirus designated SARS-CoV-2. The principal cause of death from COVID-19 disease quickly emerged as acute respiratory distress syndrome (ARDS). A key ARDS pathogenic mechanism is the “Cytokine Storm”, which is a dramatic increase in inflammatory cytokines in the blood. In the last two years of the pandemic, a new pathology has emerged in some COVID-19 survivors, in which a variety of long-term symptoms occur, a condition called post-acute sequelae of COVID-19 (PASC) or “Long COVID”. Therefore, there is an urgent need to better understand the mechanisms of the virus. The spike protein on the surface of the virus is composed of joined S1–S2 subunits. Upon S1 binding to the ACE2 receptor on human cells, the S1 subunit is cleaved and the S2 subunit mediates the entry of the virus. The S1 protein is then released into the blood, which might be one of the pivotal triggers for the initiation and/or perpetuation of the cytokine storm. In this study, we tested the hypothesis that the S1 spike protein is sufficient to activate inflammatory signaling and cytokine production, independent of the virus. Our data support a possible role for the S1 spike protein in the activation of inflammatory signaling and cytokine production in human lung and intestinal epithelial cells in culture. These data support a potential role for the SARS-CoV-2 S1 spike protein in COVID-19 pathogenesis and PASC.

Role of Genetic Polymorphism Present in Macrophage Activation Syndrome Pathway in Post Mortem Biopsies of Patients with COVID-19

COVID-19 is a viral disease associated with an intense inflammatory response. Macrophage Activation Syndrome (MAS), the complication present in secondary hemophagocytic lymphohistiocytosis (sHLH), shares many clinical aspects observed in COVID-19 patients, and investigating the cytolytic function of the responsible cells for the first line of the immune response is important. Formalin-fixed paraffin-embedded lung tissue samples obtained by post mortem necropsy were accessed for three groups (COVID-19, H1N1, and CONTROL). Polymorphisms in MAS cytolytic pathway (PRF1; STX11; STXBP2; UNC13D and GZMB) were selected and genotyping by TaqMan^® assays (Thermo Fisher Scientific, MA, USA) using Real-Time PCR (Applied Biosystems, MA USA). Moreover, immunohistochemistry staining was performed with a monoclonal antibody against perforin, CD8+ and CD57+ proteins. Histopathological analysis showed high perforin tissue expression in the COVID-19 group; CD8+ was high in the H1N1 group and CD57+ in the CONTROL group. An association could be observed in two genes related to the cytolytic pathway (PRF1 rs885822 G/A and STXBP2 rs2303115 G/A). Furthermore, PRF1 rs350947132 was associated with increased immune tissue expression for perforin in the COVID-19 group. The genotype approach could help identify patients that are more susceptible, and for this reason, our results showed that perforin and SNPs in the PRF1 gene can be involved in this critical pathway in the context of COVID-19.

The tryptophan catabolite or kynurenine pathway in COVID-19 and critical COVID-19: a systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) is accompanied by activated immune-inflammatory pathways and oxidative stress, which both induce indoleamine-2,3-dioxygenase (IDO), a key enzyme of the tryptophan (TRP) catabolite (TRYCAT) pathway. The aim of this study was to systematically review and meta-analyze the status of the TRYCAT pathway, including the levels of TRP and kynurenine (KYN) and the activity of IDO, as measured by the ratio of KYN/TRP.

METHODS

This systematic review searched PubMed, Google Scholar, and Web of Sciences and included 14 articles that compared TRP and tryptophan catabolites (TRYCATs) in COVID-19 patients versus non-COVID-19 controls, as well as severe/critical versus mild/moderate COVID-19. The analysis was done on a total of 1269 people, including 794 COVID-19 patients and 475 controls.

RESULTS

The results show a significant (p < 0.0001) increase in the KYN/TRP ratio (standardized mean difference, SMD = 1.099, 95% confidence interval, CI: 0.714; 1.484) and KYN (SMD = 1.123, 95% CI: 0.730; 1.516) and significantly lower TRP (SMD = - 1.002, 95%CI: - 1.738; - 0.266) in COVID-19 versus controls. The KYN/TRP ratio (SMD = 0.945, 95%CI: 0.629; 1.262) and KYN (SMD = 0.806, 95%CI: 0.462; 1.149) were also significantly (p < 0.0001) higher and TRP lower (SMD = - 0.909, 95% CI: - 1.569; - 0.249) in severe/critical versus mild/moderate COVID-19. No significant difference was detected in kynurenic acid (KA) and the KA/KYN ratio between COVID-19 patients and controls.

CONCLUSIONS

Our results indicate increased activity of the IDO enzyme in COVID-19 and severe/critical patients. The TRYCAT pathway is implicated in the pathophysiology and progression of COVID-19 and may signal a worsening outcome of the disease.

What Do We Need to Know About Musculoskeletal Manifestations of COVID-19?: A Systematic Review

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COVID-19 is a disease that is challenging science, health-care systems, and humanity. An astonishingly wide spectrum of manifestations of multi-organ damage, including musculoskeletal, can be associated with SARS-CoV-2.

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In the acute phase of COVID-19, fatigue, myalgia, and arthralgia are the most common musculoskeletal symptoms.

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Post-COVID-19 syndrome is a group of signs and symptoms that are present for >12 weeks. The associated musculoskeletal manifestations are fatigue, arthralgia, myalgia, new-onset back pain, muscle weakness, and poor physical performance.

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Data on COVID-19 complications are growing due to large absolute numbers of cases and survivors in these 2 years of the pandemic. Additional musculoskeletal manifestations encountered are falls by the elderly, increased mortality after hip fracture, reduced bone mineral density and osteoporosis, acute sarcopenia, rhabdomyolysis, Guillain-Barré syndrome, muscle denervation atrophy, fibromyalgia, rheumatological disease triggering, septic arthritis, adhesive capsulitis, myositis, critical illness myopathy, onset of latent muscular dystrophy, osteonecrosis, soft-tissue abscess, urticarial vasculitis with musculoskeletal manifestations, and necrotizing autoimmune myositis.

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A wide range of signs and symptoms involving the musculoskeletal system that affect quality of life and can result in a decrease in disability-adjusted life years. This powerful and unpredictable disease highlights the importance of multimodality imaging, continuing education, and multidisciplinary team care to support preventive measures, diagnosis, and treatment.

Anakinra treatment efficacy in reduction of inflammatory biomarkers in COVID-19 patients: A meta-analysis

Introduction

Anakinra is being empirically considered for the treatment of COVID‐19 patients. The aim is to assess the efficacy of anakinra treatment on inflammatory marker reduction, including c‐reactive protein (CRP) concentrations, serum ferritin, and serum d‐dimer levels.

Methods

Adhering to PRISMA 2020 statement guidelines, a systematic search was conducted across the following databases from December 2019 until January 10, 2022: PubMed/MEDLINE, Cochrane Central, Web of Science, Scopus, and EMBASE. The following keywords were employed: Anakinra, COVID*, SARS‐CoV‐2, inflammatory, CRP, D‐dimer, Ferritin, hematological, laboratory, clinical, trials. The findings were collated and presented in a tabulated manner, and statistically analyzed using Review Manger 5.4 (Cochrane).

Results

In total, 2032 patients were included (881 in the anakinra and 1151 in the control/standard care group); 69.1% of them were males. Overall, the mean difference from admission until last follow‐up in CRP values was −9.66, where notable reductions were seen in the anakinra group (SMD = −0.46, p < 0.00001, N = 655). Serum ferritin mean values were reduced by 1467.16 in the anakinra group (SMD = −0.31, p = 0.004, N = 537). D‐dimer mean values were largely reduced by 4.04 in the anakinra group (SMD = −0.38, p = 0.0004, N = 375).

Conclusion

This study finds that anakinra is potentially a strong candidate as an anti‐inflammatory agent to reduce mortality in COVID‐19 patients, specifically in patients with elevated inflammatory biomarkers.

Infection-Triggered Hyperinflammatory Syndromes in Children

An association between infectious diseases and macrophage activation syndrome (MAS) has been reported, yet the exact role of infection in MAS development is still unclear. Here, a retrospective analysis of the clinical records of patients with rheumatic diseases complicated with MAS who were treated in a pediatric tertiary care center between 2011 and 2020 was performed. Any infection documented within the 30 days preceding the onset of MAS was reported. Out of 125 children in follow-up for systemic rheumatic diseases, 12 developed MAS, with a total of 14 episodes. One patient experienced three episodes of MAS. Clinical and/or laboratory evidence of infection preceded the onset of MAS in 12 events. Clinical features, therapeutic strategies, and patient outcomes were described. The aim of this study was to evaluate the possible role of infection as a relevant trigger for MAS development in children with rheumatic conditions. The pathogenetic pathways involved in the cross-talk between uncontrolled inflammatory activity and the immune response to infection deserve further investigation.

Implications of SARS-CoV-2 Infection in Systemic Juvenile Idiopathic Arthritis

Systemic juvenile idiopathic arthritis (sJIA) is a serious multifactorial autoinflammatory disease with a significant mortality rate due to macrophage activation syndrome (MAS). Recent research has deepened the knowledge about the pathophysiological mechanisms of sJIA-MAS, facilitating new targeted treatments, and biological disease-modifying antirheumatic drugs (bDMARDs), which significantly changed the course of the disease and prognosis. This review highlights that children are less likely to suffer severe COVID-19 infection, but at approximately 2–4 weeks, some cases of multisystem inflammatory syndrome in children (MIS-C) have been reported, with a fulminant course. Previous established treatments for cytokine storm syndrome (CSS) have guided COVID-19 therapeutics. sJIA-MAS is different from severe cases of COVID-19, a unique immune process in which a huge release of cytokines will especially flood the lungs. In this context, MIS-C should be reinterpreted as a special MAS, and long-term protection against SARS-CoV-2 infection can only be provided by the vaccine, but we do not yet have sufficient data. COVID-19 does not appear to have a substantial impact on rheumatic and musculoskeletal diseases (RMDs) activity in children treated with bDMARDs, but the clinical features, severity and outcome in these patients under various drugs are not yet easy to predict. Multicenter randomized controlled trials are still needed to determine when and by what means immunoregulatory products should be administered to patients with sJIA-MAS with a negative corticosteroid response or contraindications, to optimize their health and safety in the COVID era.

Enigma of COVID-19: is “multisystem inflammatory syndrome in adults” (MIS-A) predictable?

Background

Severe inflammation and one or more extrapulmonary organ dysfunctions have been reported and this clinical picture is defined as "multisystem inflammatory syndrome in adults" (MIS-A) in severe coronavirus disease-2019 (COVID-19). We aimed to determine the effect of LDH/lymphocyte ratio (LLR) on the development of MIS-A.

Methods

The data of 2333 patients were retrospectively analyzed.

Results

MIS-A rate was found to be 9.9% and MIS-A related mortality was 35.3%. LRR level above 0.24 was found to predict MIS-A development with 70% sensitivity and 65.2% specificity. The risk of MIS-A development was found to be 3.64 times higher in those with LRR levels above 0.24 compared to those with 0.24 and below. In patients with MIS-A, LRR level above 0.32 predicts mortality with 78% sensitivity and 70% specificity.

Conclusions

Early detection of MIS-A with high sensitivity and specificity in a practical ratio is very important in terms new studies.

COVID-19-Associated Candidiasis: Possible Patho-Mechanism, Predisposing Factors, and Prevention Strategies

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is threatening public health. A large number of affected people need to be hospitalized. Immunocompromised patients and ICU-admitted patients are predisposed to further bacterial and fungal infections, making patient outcomes more critical. Among them, COVID-19-associated candidiasis is becoming more widely recognized as a part of severe COVID-19 sequelae. While the molecular pathophysiology is not fully understood, some factors, including a compromised immune system, iron and zinc deficiencies, and nosocomial and iatrogenic transmissions, predispose COVID-19 patients to candidiasis. In this review, we discuss the existing knowledge of the virulence characteristics of Candida spp. and summarize the key concepts in the possible molecular pathogenesis. We analyze the predisposing factors that make COVID-19 patients more susceptible to candidiasis and the preventive measures which will provide valuable insights to guide the effective prevention of candidiasis in COVID-19 patients.

Macrophages: shapes and functions

Macrophages are cells of the innate immune system and represent an important component of the first-line defense against pathogens and tumor cells. Here, their diverse functions in inflammation and tumor defense are described, and the mechanisms, tools, and activation pathways and states applied are presented. The main focus is on the role and origin of reactive oxygen species (ROS), the important signal pathways TLR/NF-κB, and the M1/​​M2 polarization of macrophages.

Upregulation of type 1 conventional dendritic cells implicates antigen cross-presentation in multisystem inflammatory syndrome

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is an acute, febrile, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated syndrome, often with cardiohemodynamic dysfunction. Insight into mechanism of disease is still incomplete.

OBJECTIVE

Our objective was to analyze immunologic features of MIS-C patients compared to febrile controls (FC).

METHODS

MIS-C patients were defined by narrow criteria, including having evidence of cardiohemodynamic involvement and no macrophage activation syndrome. Samples were collected from 8 completely treatment-naive patients with MIS-C (SARS-CoV-2 serology positive), 3 patients with unclassified MIS-C-like disease (serology negative), 14 FC, and 5 MIS-C recovery (RCV). Three healthy controls (HCs) were used for comparisons of normal range. Using spectral flow cytometry, we assessed 36 parameters in antigen-presenting cells (APCs) and 29 in T cells. We used biaxial analysis and uniform manifold approximation and projection (UMAP).

RESULTS

Significant elevations in cytokines including CXCL9, M-CSF, and IL-27 were found in MIS-C compared to FC. Classic monocytes and type 2 dendritic cells (DCs) were downregulated (decreased CD86, HLA-DR) versus HCs; however, type 1 DCs (CD11c+CD141+CLEC9A+) were highly activated in MIS-C patients versus FC, expressing higher levels of CD86, CD275, and atypical conventional DC markers such as CD64, CD115, and CX3CR1. CD169 and CD38 were upregulated in multiple monocyte subtypes. CD56dim/CD57-/KLRGhi/CD161+/CD38- natural killer (NK) cells were a unique subset in MIS-C versus FC without macrophage activation syndrome.

CONCLUSION

Orchestrated by complex cytokine signaling, type 1 DC activation and NK dysregulation are key features in the pathophysiology of MIS-C. NK cell findings may suggest a relationship with macrophage activation syndrome, while type 1 DC upregulation implies a role for antigen cross-presentation.

Secondary Hemophagocytic Lymphohistiocytosis in a Post-COVID-19 Patient

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition caused by excessive immune system activation. HLH can be primary or secondary. Primary HLH is commonly seen in children with underlying genetic mutations, while secondary HLH can be seen at any age. It is usually triggered by inciting factors such as viral infections, patients with underlying rheumatological disease, or malignancies. It has very poor prognosis if left untreated, with survival of only a few months. While there have been around 100 cases of HLH reported during the acute phase of COVID-19 infection, very few post-COVID-19 HLH cases have been reported, only around 35 cases. Here we report a case of a 20-year-old Caucasian male who presented eight weeks after COVID-19 infection with extreme fatigue, fever, lab work concerning for HLH, and a high H score indicating a high probability of HLH. Early identification of HLH following COVID-19 recovery would allow for timely management of the condition.

The Treatment of COVID-19 Purgatory Syndrome With Tocilizumab and Steroids

Hyperinflammation is a key component of severe coronavirus disease 2019 (COVID-19) and is associated with poor outcomes. It is imperative to distinguish severe COVID-19 from hyperinflammatory syndromes such as multisystem inflammatory syndrome (MIS) and hemophagocytic lymphohistiocytosis. There is a subset of post-COVID-19 patients who present with some symptoms characteristic of MIS in adults (MIS-A) yet do not meet all the criteria for a diagnosis. We describe the unique case of a patient with this kind of presentation who clinically improved following tocilizumab and corticosteroid usage.

Intrinsic Antiviral Activity of Optineurin Prevents Hyperproliferation of a Primary Herpes Simplex Virus Type 2 Infection

Very little knowledge exists on virus-specific host cell intrinsic mechanisms that prevent hyperproliferation of primary HSV type 2 (HSV-2) genital infections. In this study, we provide evidence that the Nemo-related protein, optineurin (OPTN), plays a key role in restricting HSV-2 infection both in vitro and in vivo. Contrary to previous reports regarding the proviral role of OPTN during Sendai virus infection, we demonstrate that lack of OPTN in cells causes enhanced virus production. OPTN deficiency negatively affects the host autophagy response and results in a marked reduction of CCL5 induction. OPTN knockout (OPTN^-/-) mice display exacerbated genital disease and dysregulated T cell frequencies in infected tissues and lymph nodes. A human transcriptomic profile dataset provides further credence that a strong positive correlation exists between CCL5 upregulation and OPTN expression during HSV-2 genital infection. Our findings underscore a previously unknown OPTN/CCL5 nexus that restricts hyperproliferative spread of primary HSV-2 infection, which may constitute an intrinsic host defense mechanism against herpesviruses in general.

Increased Kynurenine Indicates a Fatal Course of COVID-19

(1) Background: An inefficient immune response accompanied by an overwhelming inflammatory reaction is involved in severe courses of COVID-19. Kynurenine (KYN) has important immune-modulatory functions and may contribute to a failure in controlling SARS-CoV-2. The present study aims to explore biomarkers that hint at a fatal outcome of COVID-19 early on. (2) Methods: We established a cohort of 148 hospitalized COVID-19 patients for this study. Thirty-one patients died due to a severe COVID-19 course, and 117 recovered within 90 days. We built a biobank by collecting left-over material from these patients whenever blood arrived at the central laboratory of our University hospital for analysis of routine markers. The scientific laboratory analysis comprised KYN, Tryptophan (TRP), KYN/TRP ratio, ferritin, interleukin-6 (IL-6), C-reactive protein (CRP), creatinine, N-terminal pro-natriuretic peptide (NTproBNP), troponin T (TnT), fibrinogen, D-Dimer, prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin (AT), protein C, protein S, factor XIII, lupus aPTT, angiotensin-2, vitamin D metabolites, and telomeres in all COVID-19 patients. Basic clinical characteristics and anteceding diseases including cardiovascular, oncologic, renal, hypertension, pulmonary, metabolic (diabetes, obesity) were recorded in a database together with the laboratory data. (3) Results: At the time of diagnosis of SARS-CoV-2 infection those patients who deceased within 90 days afterwards due to COVID-19, had a significantly higher age, higher KYN, KYN/TRP ratio, ferritin, creatinine, and NTproBNP values than SARS-CoV-2 patients who survived COVID-19 along the same time span. In a Kaplan-Meier analysis the variables age, KYN, ferritin, D-Dimer, TnT, NTproBNP, and creatinine showed a significant influence on survival time. Gender, however, showed no influence. In a combined Cox regression analysis KYN had the highest hazard ratio (1.188, 95% CI: 1.071-1.319) followed by age (1.041, 95% CI: 1.011-1.073). In a ROC analysis, KYN values above the cut off limit of 4.82 nmol/l (as specified by Youden index) had a sensitivity of 82% (95% CI: 66-95%) and a specificity of 72% (95% CI: 65-82%) to predict COVID-19 related death within 90 days observation time. (4) Conclusions: Kynurenine is a promising blood biomarker to predict an increased risk of mortality in SARS-CoV-2 infected people already at the time of the first positive SARS-CoV-2 verification detected in these persons.

Incidental diagnosis of a large cardiac thrombus swinging through an interatrial communication in a COVID-19 patient: Case report and literature review

Introduction

The hypercoagulability state induced by COVID-19 has been well established and various forms of subsequent thromboembolic events have been reported throughout literature including multiple cases of intracardiac thrombi, four of which in our center alone, this case being the fifth.

Case report

We report the case of a 38-year-old male with no prior cardiovascular history who -subsequently to a COVID-19 infection-developped a right atrial thrombosis associated to a pulmonary embolism, and in whom cardiography revealed an interatrial communication. Management relied upon curative doses of low molecular weight heparin (LMWH) with favourable outcome.

Discussion

In our discussion, we lay out the various physiopathological mechanisms incriminated throughout literature in the genesis of a hypercoagulability state distinctive of COVID-19, before highlighting the incidence of an interatrial communication (whether a Potent Foramen Ovale or Atrial Septal Defect) discovered in patients with COVID-19, and the potential paradoxical embolization risks they imply as well as reported cases. A mention of hemostatic parameters monitored was also warranted. Finally we discuss the guidelines in terms of prophylactic and therapeutic anticoagulation in hospitalized patients before discussing cardiac thrombosis's therapeutic options.

Conclusion

Our case highlights various key points which could change the prognosis of COVID-19 patients, whether related to the underdiagnosis of interatrial abnormalities or with regards to the diagnosis to thromboembolic events, but also the indisputable place of anticoagulation in COVID-19 management.

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Thromboembolic events complicating COVID-19 have been well described and are attributed to a hypercoagulability state distinctive of COVID-19.

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A pre-existing Potent Foramen Ovale (PFO) or Atrial septal Defect (ASD) in COVID-19 patients is unknown as only a handful of studies covered the subject.

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The association of a cardiac thrombosis with a pulmonary embolism and interatrial communication exposes patients to risks of paradoxical embolization and subsequent arterial thrombotic events.

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Prophylactic and curatrive anticoagulation is unrefutably a key pillar in the management of COVID-19.

Recent Advances of COVID-19 Modeling Based on Regenerative Medicine

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has caused a pandemic since December 2019 that originated in Wuhan, China. Soon after that, the world health organization declared Coronavirus disease-2019 a global health concern. SARS-CoV-2 is responsible for a lethal respiratory infection as well as the involvement of other organs due to its large tropism spectrum such as neurologic, cardiovascular, endocrine, gastrointestinal, and renal systems. Since the behavior of the virus is not fully understood, a new manifestation of the infection is revealed every day. In order to be able to design more efficient drugs and vaccines to treat the infection, finding out the exact mechanism of pathogenicity would be necessary. Although there have been some big steps toward understanding the relevant process, there are still some deficiencies in this field. Accordingly, regenerative medicine (RM), can offer promising opportunities in discovering the exact mechanisms and specific treatments. For instance, since it is not always possible to catch the pathophysiology mechanisms in human beings, several modeling methods have been introduced in this field that can be studied in three main groups: stem cell-based models, organoids, and animal models. Regarding stem cell-based models, induced pluripotent stem cells are the major study subjects, which are generated by reprogramming the somatic stem cells and then directing them into different adult cell populations to study their behavior toward the infection. In organoid models, different cell lines can be guided to produce a 3D structure including liver, heart, and brain-like platforms. Among animal models, mice are the most common species in this field. However, in order for mice models to be permissive to the virus, angiotensin-converting enzyme 2 receptors, the main receptor involved in the pathogenicity of the virus, should be introduced to the host cells through different methods. Here, the current known mechanism of SARS-CoV-2 infection, different suggested models, the specific response toward different manipulation as well as challenges and shortcomings in each case have been reviewed. Finally, we have tried to provide a quick summary of the present available RM-based models for SARS-CoV-2 infection, as an essential part of developing drugs, for future therapeutic goals.

An overview on tumor treating fields (TTFields) technology as a new potential subsidiary biophysical treatment for COVID-19

COVID-19 pandemic situation has affected millions of people with tens of thousands of deaths worldwide. Despite all efforts for finding drugs or vaccines, the key role for the survival of patients is still related to the immune system. Therefore, improving the efficacy and the functionality of the immune system of COVID-19 patients is very crucial. The potential new, non-invasive, FDA-approved biophysical technology that could be considered in this regard is tumor treating fields (TTFields) based on an alternating electric field has great biological effects. TTFields have significant effects in improving the functionality of dendritic cell, and cytotoxic T-cells, and these cells have a major role in defense against viral infection. Hence, applying TTFields could help COVID-19 patients against infection. Additionally, TTFields can reduce viral genomic replication, by reducing the expressions of some of the vital members of DNA replication complex genes from the minichromosome maintenance family (MCMs). These genes not only are involved in DNA replication but it has also been proven that they have a crucial role in viral replication. Also, TTFields suppress the formation of the network of tunneling nanotubes (TNTs) which is knows as filamentous (F)-actin-rich tubular structures. TNTs have a critical role in promoting the spread of viruses through improving viral entry and acting as a protective agent for viral components from immune cells and even pharmaceuticals. Moreover, TTFields enhance autophagy which leads to apoptosis of virally infected cells. Thus, it can be speculated that using TTFields may prove to be a promising approach as a subsidiary treatment of COVID-19.

Acute limb ischemia with concomitant splenic and renal infarcts: Thromboembolic events revealing COVID-19

Introduction

Since December 2019, the coronavirus 19 (COVID-19) pandemic continues to spread worldwide and has caused millions of deaths. Although the main manifestation of the disease is acute respiratory distress syndrome, hypercoagulability resulting from hypoxemia leads to venous thromboembolism and arterial thrombosis, which have a fatal prognosis for COVID-19.

Case report management

We report the case of patient admitted to our unit for management of a concomitant limb ischemia, splenic and renal infarcts associated to a COVID-19 infection with favorable outcomes after thrombectomy and therapeutic doses of heparin.

Conclusion

Systemic procoagulant manifestations related to a COVID-19 infection is a newly described phenomenon responsible of cardiovascular and neurological disorders.

Innate lymphoid cells (ILC) in SARS-CoV-2 infection

Innate Lymphoid Cells (ILCs) are a class of innate immune cells that form the first line of defense against internal or external abiotic and biotic challenges in the mammalian hosts. As they reside in both the lymphoid and non-lymphoid tissues, they are involved in clearing the pathogens through direct killing or by secretion of cytokines that modulate the adaptive immune responses. There is burgeoning evidence that these cells are important in clearing viral infections; therefore, it is critical to understand their role in the resolution or exacerbation of the disease caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2). In this review, we summarize the recent findings related to ILCs in response to SARS-CoV-2 infections.

Potential Adverse Effects of Dexamethasone Therapy on COVID-19 Patients: Review and Recommendations

In the context of the coronavirus disease 2019 (COVID-19) pandemic, the global healthcare community has raced to find effective therapeutic agents against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, dexamethasone is the first and an important therapeutic to significantly reduce the risk of death in COVID-19 patients with severe disease. Due to powerful anti-inflammatory and immunosuppressive effects, dexamethasone could attenuate SARS-CoV-2-induced uncontrolled cytokine storm, severe acute respiratory distress syndrome and lung injury. Nevertheless, dexamethasone treatment is a double-edged sword, as numerous studies have revealed that it has significant adverse impacts later in life. In this article, we reviewed the literature regarding the adverse effects of dexamethasone administration on different organ systems as well as related disease pathogenesis in an attempt to clarify the potential harms that may arise in COVID-19 patients receiving dexamethasone treatment. Overall, taking the threat of COVID­19 pandemic into account, we think it is necessary to apply dexamethasone as a pharmaceutical therapy in critical patients. However, its adverse side effects cannot be ignored. Our review will help medical professionals in the prognosis and follow-up of patients treated with dexamethasone. In addition, given that a considerable amount of uncertainty, confusion and even controversy still exist, further studies and more clinical trials are urgently needed to improve our understanding of the parameters and the effects of dexamethasone on patients with SARS-CoV-2 infection.

Interplay between Neutrophils, NETs and T-Cells in SARS-CoV-2 Infection-A Missing Piece of the Puzzle in the COVID-19 Pathogenesis?

Since the end of 2019, a new, dangerous virus has caused the deaths of more than 3 million people. Efforts to fight the disease remain multifaceted and include prophylactic strategies (vaccines), the development of antiviral drugs targeting replication, and the mitigation of the damage associated with exacerbated immune responses (e.g., interleukin-6-receptor inhibitors). However, numerous uncertainties remain, making it difficult to lower the mortality rate, especially among critically ill patients. While looking for a new means of understanding the pathomechanisms of the disease, we asked a question-is our immunity key to resolving these uncertainties? In this review, we attempt to answer this question, and summarize, interpret, and discuss the available knowledge concerning the interplay between neutrophils, neutrophil extracellular traps (NETs), and T-cells in COVID-19. These are considered to be the first line of defense against pathogens and, thus, we chose to emphasize their role in SARS-CoV-2 infection. Although immunologic alterations are the subject of constant research, they are poorly understood and often underestimated. This review provides background information for the expansion of research on the novel, immunity-oriented approach to diagnostic and treatment possibilities.

Problems of Pathogenesis and Pathogenetic Therapy of COVID-19 from the Perspective of the General Theory of Pathological Systems (General Pathological Processes)

The COVID-19 pandemic examines not only the state of actual health care but also the state of fundamental medicine in various countries. Pro-inflammatory processes extend far beyond the classical concepts of inflammation. They manifest themselves in a variety of ways, beginning with extreme physiology, then allostasis at low-grade inflammation, and finally the shockogenic phenomenon of "inflammatory systemic microcirculation". The pathogenetic core of critical situations, including COVID-19, is this phenomenon. Microcirculatory abnormalities, on the other hand, lie at the heart of a specific type of general pathological process known as systemic inflammation (SI). Systemic inflammatory response, cytokine release, cytokine storm, and thrombo-inflammatory syndrome are all terms that refer to different aspects of SI. As a result, the metabolic syndrome model does not adequately reflect the pathophysiology of persistent low-grade systemic inflammation (ChSLGI). Diseases associated with ChSLGI, on the other hand, are risk factors for a severe COVID-19 course. The review examines the role of hypoxia, metabolic dysfunction, scavenger receptors, and pattern-recognition receptors, as well as the processes of the hemophagocytic syndrome, in the systemic alteration and development of SI in COVID-19.

Coagulation and wound repair during COVID-19

While COVID-19 is best known as a respiratory infection, SARS-CoV-2 causes systemic disease manifestations including coagulopathies. Both dysregulated extracellular matrix remodeling pathways and circulating coagulation proteins are hallmarks of severe COVID-19 and often continue after the resolution of acute infection. Coagulation proteins have proven effective as biomarkers for severe disease and anticoagulants are a mainstay of COVID-19 therapeutics in hospitalized patients. While much knowledge has been gained about the role of clotting pathway activation in COVID-19, much remains to be elucidated in this complex network of signaling pathways.

Hemophagocytic lymphohistiocytosis, a new cause of death during 'post-acute COVID-19 syndrome?' A case report

'Post-acute coronavirus disease 2019 (COVID-19) syndrome' is a new term that was coined to describe a constellation of persistent symptoms and new complications following recovery from COVID-19 initial illness. Identifying post-COVID-19 complications is crucial for early diagnosis and subsequent initiation of therapies to ensure more favorable outcomes. Severe COVID-19-related hemophagocytic lymphohistiocytosis (HLH) has been previously described during the acute phase of the infection. It is characterized by hyperinflammation, multi-organ involvement, and hemophagocytosis. We report the case of a 69-year-old woman who presented, two weeks after recovery from COVID-19, with hyperosmolar state and high inflammatory markers. Bone marrow aspirate, flow cytometry, extensive viral panel and total body scan were performed. Review of bone marrow aspirate smear showed hemophagocytosis. Flow cytometry, viral panel, and total body scan were normal. The diagnosis of post COVID-19-related HLH was made. Unfortunately, the patient died despite adequate treatment. To our knowledge, this is the first case establishing a high probability of COVID-19-related HLH given its occurrence two weeks following a documented biological and clinical recovery. Awareness and early recognition of HLH features following COVID-19 recovery should prompt timely initiation of therapy.