The Role of Cytokines including Interleukin-6 in COVID-19 induced Pneumonia and Macrophage Activation Syndrome-Like Disease

Immunity and Coagulation in COVID-19

Discovered in late 2019, the SARS-CoV-2 coronavirus has caused the largest pandemic of the 21st century, claiming more than seven million lives. In most cases, the COVID-19 disease caused by the SARS-CoV-2 virus is relatively mild and affects only the upper respiratory tract; it most often manifests itself with fever, chills, cough, and sore throat, but also has less-common mild symptoms. In most cases, patients do not require hospitalization, and fully recover. However, in some cases, infection with the SARS-CoV-2 virus leads to the development of a severe form of COVID-19, which is characterized by the development of life-threatening complications affecting not only the lungs, but also other organs and systems. In particular, various forms of thrombotic complications are common among patients with a severe form of COVID-19. The mechanisms for the development of thrombotic complications in COVID-19 remain unclear. Accumulated data indicate that the pathogenesis of severe COVID-19 is based on disruptions in the functioning of various innate immune systems. The key role in the primary response to a viral infection is assigned to two systems. These are the pattern recognition receptors, primarily members of the toll-like receptor (TLR) family, and the complement system. Both systems are the first to engage in the fight against the virus and launch a whole range of mechanisms aimed at its rapid elimination. Normally, their joint activity leads to the destruction of the pathogen and recovery. However, disruptions in the functioning of these innate immune systems in COVID-19 can cause the development of an excessive inflammatory response that is dangerous for the body. In turn, excessive inflammation entails activation of and damage to the vascular endothelium, as well as the development of the hypercoagulable state observed in patients seriously ill with COVID-19. Activation of the endothelium and hypercoagulation lead to the development of thrombosis and, as a result, damage to organs and tissues. Immune-mediated thrombotic complications are termed "immunothrombosis". In this review, we discuss in detail the features of immunothrombosis associated with SARS-CoV-2 infection and its potential underlying mechanisms.

Changes in the Repertoire of tRNA-Derived Fragments in Different Blood Cell Populations

tRNA-derived fragments function as markers in addition to playing the key role of signalling molecules in a number of disorders. It is known that the repertoire of these molecules differs greatly in different cell types and varies depending on the physiological condition. The aim of our research was to compare the pattern of tRF expression in the main blood cell types and to determine how the composition of these molecules changes during COVID-19-induced cytokine storms. Erythrocytes, monocytes, lymphocytes, neutrophils, basophils and eosinophils from control donors and patients with severe COVID-19 were obtained by fluorescence sorting. We extracted RNA from FACS-sorted cells and performed NGS of short RNAs. The composition of tRNA-derived fragments was analysed by applying a semi-custom bioinformatic pipeline. In this study, we assessed the length and type distribution of tRFs and reported the 150 most prevalent tRF sequences across all cell types. Additionally, we demonstrated a significant (p < 0.05, fold change >16) change in the pattern of tRFs in erythrocytes (21 downregulated, 12 upregulated), monocytes (53 downregulated, 38 upregulated) and lymphocytes (49 upregulated) in patients with severe COVID-19. Thus, different blood cell types exhibit a significant variety of tRFs and react to the cytokine storm by dramatically changing their differential expression patterns. We suppose that the observed phenomenon occurs due to the regulation of nucleotide modifications and alterations in activity of various Rnases.

Multifarious Aspect of Cytokines as an Immuno-Therapeutic for Various Diseases

Cytokines are known to be a group of growing small proteins that are majorly responsible for the transmission of signals and communication between hematopoietic cells, the cells of the human immune system, and other types of cells. Cytokines play a dominant role in different types of disorders and in perpetuating the inflammation-related disorders. The production of cytokines is a natural process inside the body of a human being against any foreign invasion or due to some pathogenic state to maintain the homeostasis. Cytokines respond in two ways; in some cases, the production and development of cytokines as a therapeutic discovery or intervention will enhance the treatment process and support the reaction given by the body against any pathogenic activity, and in some cases, overproduction of these cytokines responds in the opposite way and behaves as antagonists toward a typical therapeutic drug and its treatment. Overall, 41 articles were reviewed, and it was found that cytokines have proved to be a therapeutic approach among various diseases and can be utilized as a good candidate or a better choice for cancer therapeutics in future development.

Trends in Sudden Unexpected Deaths in an Australian Population: Impact of the COVID-19 Pandemic

BACKGROUND AND AIM

SARS-CoV-2 infection is associated with increased cardiovascular (CV) morbidity and mortality, manifesting as increased adverse outcomes in the first 30 days, extending to 12 months. This study aimed to investigate trends in sudden unexpected deaths between 2018 and 2022, with a focus on CV deaths.

METHOD

A retrospective analysis was performed on autopsy reports (n=9,330) obtained from New South Wales Coroners Court, Australia, specifically targeting cases of unexplained deaths that occurred between 2018 and 2022. Statistical analysis was conducted using chi-square tests and a post hoc analysis with Bonferroni correction, as well as analysis of variance with multiple comparisons.

RESULTS

There were 349 (18.3%) CV deaths in 2018, 346 (18.0%) in 2019, 338 (17.5%) in 2020, 395 (21.9%) in 2021, and (23.4%) 413 in 2022 (p=0.0002). Among CV deaths, the number of deaths from sudden arrhythmic death syndrome were 25 (7.2%) in 2018, 26 (7.5%) in 2019, 18 (5.3%) in 2020, 52 (13.2%) in 2021, and 80 (19.4%) in 2022 (p=0.0001). Atherosclerosis was the most common cause of death among all CV categories; there were 196 (56.2%) atherosclerosis deaths in 2018, 207 (59.8%) in 2019, 192 (56.8%) in 2020, 221 (56.0%) in 2021, and 197 (47.7%) in 2022 (p=0.43). The average age of death from sudden arrhythmic death syndrome (42.8±19.1 years) across 2018-2022 was younger than atherosclerosis (56.2±12.4 years) and total groups (53.1±15.1 years) (p<0.001). Males comprised 76% of all CV deaths from 2018 to 2022 (p<0.0001).

CONCLUSIONS

Compared with pre-pandemic data, a noteworthy increase in CV deaths was observed in occurrence with the escalation in COVID-19 cases in Australia. This may be attributed to direct or indirect factors, such as lifestyle modifications, disrupted access to routine cardiac care, or COVID-19 infection-triggered CV deaths.

Hemophagocytosis of the Hilar Pulmonary Lymph Nodes Is a More Sensitive Indicator of the Severity of COVID-19 Disease than Bone Marrow Hemophagocytosis

In systemic hyper-inflammation, as in severe COVID-19 disease, there are pronounced disorders of the hematological and lymphatic systems with prognostically relevant hemophagocytosis of the bone marrow. The current work aimed to address the importance of hemophagocytosis in the lymph nodes of patients with severe COVID-19 disease. From 28 patients who died of severe COVID-19 infection, samples of the vertebral bone marrow and lymph nodes from the cervical, hilar, para-aortic, mesenteric and inguinal locations were morphologically and immunohistologically (CD163, CD68, CD61, CD71, CD3, CD20, CD138) examined for the possible presence of hemophagocytosis. In the single-center study at the University Hospital Jena, a total of 191 hemophagocytes were found in the bone marrow and a total of 780 hemophagocytes in the lymph nodes in a standardized area of 21,924 mm2 per tissue sample. With 370 hemophagocytes, hilar lymph nodes were most frequently affected (370/780; 47.44%; 95%-CI: [43.94, 50.95]), followed by cervical lymph nodes (206/780; 26.41%; 95%-CI: [23.41, 29.59]), para-aortic lymph nodes (125/780; 16.03%; 95%-CI: [13.58, 18.73]) and inguinal/mesenteric lymph nodes (79/780; 10.13%; 95%-CI: [8.155, 12.4]). Based on the standard area (21,924 mm2), the difference in the number of hemophagocytes in the bone marrow and in the hilar lymph nodes was statistically significant (p < 0.05), while this did not apply to the lymph nodes from the other locations. In fatal COVID-19 disease, hemophagocytosis is particularly found in the hilar lymph nodes and is therefore a better indicator of the severity of the disease than hemophagocytosis in the bone marrow. The findings provide some evidence for the concept of compartmentalized human host responses to life-threatening infections.

The Interplay of HIV and Long COVID in Sub-Saharan Africa: Mechanisms of Endothelial Dysfunction

PURPOSE OF REVIEW

Long COVID affects approximately 5 million people in Africa. This disease is characterized by persistent symptoms or new onset of symptoms after an acute SARS-CoV-2 infection. Specifically, the most common symptoms include a range of cardiovascular problems such as chest pain, orthostatic intolerance, tachycardia, syncope, and uncontrolled hypertension. Importantly, these conditions appear to have endothelial dysfunction as the common denominator, which is often due to impaired nitric oxide (NO) mechanisms. This review discusses the role of mechanisms contributing to endothelial dysfunction in Long COVID, particularly in people living with HIV.

RECENT FINDINGS

Recent studies have reported that increased inflammation and oxidative stress, frequently observed in Long COVID, may contribute to NO dysfunction, ultimately leading to decreased vascular reactivity. These mechanisms have also been reported in people living with HIV. In regions like Africa, where HIV infection is still a major public health challenge with a prevalence of approximately 26 million people in 2022. Specifically, endothelial dysfunction has been reported as a major mechanism that appears to contribute to cardiovascular diseases and the intersection with Long COVID mechanisms is of particular concern. Further, it is well established that this population is more likely to develop Long COVID following infection with SARS-CoV-2. Therefore, concomitant infection with SARS-CoV-2 may lead to accelerated cardiovascular disease. We outline the details of the worsening health problems caused by Long COVID, which exacerbate pre-existing conditions such as endothelial dysfunction. The overlapping mechanisms of HIV and SARS-CoV-2, particularly the prolonged inflammatory response and chronic hypoxia, may increase susceptibility to Long COVID. Addressing these overlapping health issues is critical as it provides clinical entry points for interventions that could improve and enhance outcomes and quality of life for those affected by both HIV and Long COVID in the region.

Syndrome of inappropriate antidiuresis/hyponatremia in COVID-19

Hyponatremia is the most frequent electrolyte alteration among hospitalized patients and it has been reported in 20-40% of patients with SARS-CoV-2 (COVID-19) infection. Multiple causes of hyponatremia have been hypothesized in these patients. The syndrome of inappropriate antidiuresis (SIAD) has been considered one of the main reasons leading to hyponatremia in this condition. SIAD can be secondary to cytokines release, in particular IL-6. Positive pressure ventilation can be another cause of hyponatremia due to SIAD. Other possible etiologies of hyponatremia in COVID-19 patients can be related to secondary hypocortisolism, nausea, vomiting, heart and kidney damage. Similar to many other clinical conditions, there is strong evidence that hyponatremia is associated with a worse prognosis also in patients with COVID-19 infection. In particular, hyponatremia has been identified as an independent risk of ICU transfer, need of non-invasive ventilation and death. Hyponatremia in COVID-19 patients is in principle acute and symptomatic and should be treated as such, according to the published guidelines. Therefore, patients should be initially treated with i.v. hypertonic saline (3% NaCl) infusion and serum [Na+] should be frequently monitored, in order to remain within a safe rate of correction. There is evidence showing that serum [Na+] correction is associated with a better outcome in different pathologies, including COVID-19 infection.

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.

Autopsy findings from patients diagnosed with COVID-19 demonstrate unique morphological patterns in bone marrow and lymph node

AIMS

The identification of haemophagocytosis in bone marrow (BM) is recurrently identified in patients with severe COVID-19. These initial COVID-19 autopsy studies have afforded valuable insight into the pathophysiology of this disease; however, only a limited number of case series have focused on lymphoid or haematopoietic tissues.

METHODS

BM and lymph node (LN) specimens were obtained from adult autopsies performed between 1 April 2020 and 1 June 2020, for which the decedent had tested positive for SARS-CoV-2. Tissue sections (H&E, CD3, CD20, CD21, CD138, CD163, MUM1, kappa/lambda light chains in situ hybridisation) were examined by two haematopathologists, who recorded morphological features in a blinded fashion. Haemophagocytic lymphohistiocytosis (HLH) was assessed based on HLH 2004 criteria.

RESULTS

The BM demonstrated a haemophagocytic pattern in 9 out of 25 patients (36%). The HLH pattern was associated with longer hospitalisation, BM plasmacytosis, LN follicular hyperplasia and lower aspartate aminotransferase (AST), as well as ferritin at demise. LN examination showed increased plasmacytoid cells in 20 of 25 patients (80%). This pattern was associated with a low absolute monocyte count at diagnosis, lower white cell count and lower absolute neutrophil count at demise, and lower ferritin and AST at demise.

CONCLUSIONS

Autopsy results demonstrate distinct morphological patterns in BM, with or without haemophagocytic macrophages, and in LN, with or without increased plasmacytoid cells. Since only a minority of patients met diagnostic criteria for HLH, the observed BM haemophagocytic macrophages may be more indicative of an overall inflammatory state.

Changes in Circulating Adipokine Levels in COVID-19 Patients

Objective: The COVID-19 pandemic has posed significant global health challenges. Despite extensive research efforts, the inflammatory response triggered by SARS-CoV-2 remains to be further explored and understood. Our study aims to examine the changes in serum concentrations of pro-inflammatory adipokines-visfatin and leptin-in COVID-19 patients in relation to a healthy control group. Patients/Materials/Subjects and Methods: The study consisted of forty COVID-19 patients and twenty-four healthy patients in the control group. Two serum samples were collected: upon admission and on the seventh day of hospitalization. Concentrations of visfatin and leptin in the serum, alongside routine biochemical parameters, were measured using enzyme immunoassay or enzyme-linked immunosorbent assay kits. The Shapiro-Wilk test was used to assess normality. Differences between independent groups were compared using the Mann-Whitney U test and Kruskal-Wallis ANOVA. Correlations were evaluated with Spearman's rank correlation coefficient. Results: Our findings revealed significantly lower visfatin levels in COVID-19 patients compared to the control group upon admission (4.29 ng/mL, (3.0-6.88 ng/mL) vs. 37.16 ng/mL (24.74-50.12 ng/mL), p < 0.001 for visfatin 1 and 52.05 ng/mL, (31.2-69.66 ng/mL) vs. 37.16 ng/mL (24.74-50.12 ng/mL), p = 0.048 for visfatin 2). The visfatin level of COVID-19 patients returned to the normal levels, established in the control group. However, there was no significant difference in leptin levels between the two groups (p = 0.270 for leptin 1 and p = 0.129 for leptin 2). There was a positive correlation between BMI and leptin concentration (r = 0.66 and p = 0.00). Moreover, it was discovered that COVID-19 independently reduces visfatin levels during the first day of illness. Conclusions: The results of our research suggest that the onset of COVID-19 infection is correlated to visfatin levels. Association with leptin levels remains inconclusive. Further research is imperative to elucidate the intricate role of visfatin and leptin in SARS-CoV-2 infection and their potential as biomarkers for COVID-19 severity and prognosis.

Alterations in hematologic, coagulation, and inflammatory markers based on fever status in hospitalized COVID-19 patients: A retrospective study

Background

Laboratory markers like lymphopenia, thrombocytopenia, elevated D-dimer, and C-reactive protein (CRP) predict worse outcomes in coronavirus disease 2019 (COVID-19). However, a comprehensive analysis of hematologic and coagulation parameter alterations based on fever status is lacking.

Methods

This retrospective study analyzed 300 COVID-19 patients hospitalized from March to December 2020. Demographic, clinical, and laboratory data were extracted from electronic medical records. Patients were stratified into fever (n = 200) and no fever (n = 100) groups. Hematologic, coagulation, and inflammatory markers were compared between groups using appropriate statistical tests. Multivariate regression identified independent predictors of fever.

Results

Fever was associated with leukocytosis, neutrophilia, lymphopenia, thrombocytopenia, elevated CRP, D-dimer, procalcitonin, interleukin-6, neutrophil to lymphocyte ratio (NLR), and ferritin compared to no fever (all P < 0.05). D-dimer (r = 0.42), CRP (r = 0.52), NLR (r = 0.48), and interleukin-6 (r = 0.46) demonstrated the strongest correlation with fever (P < 0.001). High D-dimer >1000 ng/mL (adjusted odds ratio 2.7), CRP >100 mg/L (3.1), lymphopenia <1.0 × 109/L (2.8), NLR >4 (2.9), and thrombocytopenia <150 × 109/L (2.7) were significant independent predictors of fever status (P < 0.005). These parameters had moderate sensitivity (40-60%) and high specificity (74-88%) for discriminating febrile patients with AUC of 0.85.

Conclusions

Marked alterations in hematologic, coagulation, and inflammatory markers occur in COVID-19 based on fever. Routine laboratory parameters can facilitate diagnosis and risk stratification.

Cerebral microbleeds in patients with COVID-19: is there an inevitable connection?

The COVID-19 pandemic has underscored the critical interplay between systemic infections and neurological complications, notably cerebral microbleeds. This comprehensive review meticulously aggregates and analyses current evidence on cerebral microbleeds' prevalence, pathophysiological underpinnings and clinical implications within COVID-19 cohorts. Our findings reveal a pronounced correlation between cerebral microbleeds and increased severity of COVID-19, emphasizing the role of direct viral effects, inflammatory responses and coagulation disturbances. The documented association between cerebral microbleeds and elevated risks of morbidity and mortality necessitates enhanced neurological surveillance in managing COVID-19 patients. Although variability in study methodologies presents challenges, the cumulative evidence substantiates cerebral microbleeds as a critical illness manifestation rather than mere coincidence. This review calls for harmonization in research methodologies to refine our understanding and guide targeted interventions. Prioritizing the detection and study of neurological outcomes, such as cerebral microbleeds, is imperative for bolstering pandemic response strategies and mitigating the long-term neurological impact on survivors.

Immunobiology of COVID-19: Mechanistic and therapeutic insights from animal models

The distribution of the immune system throughout the body complicates in vitro assessments of coronavirus disease 2019 (COVID-19) immunobiology, often resulting in a lack of reproducibility when extrapolated to the whole organism. Consequently, developing animal models is imperative for a comprehensive understanding of the pathology and immunology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This review summarizes current progress related to COVID-19 animal models, including non-human primates (NHPs), mice, and hamsters, with a focus on their roles in exploring the mechanisms of immunopathology, immune protection, and long-term effects of SARS-CoV-2 infection, as well as their application in immunoprevention and immunotherapy of SARS-CoV-2 infection. Differences among these animal models and their specific applications are also highlighted, as no single model can fully encapsulate all aspects of COVID-19. To effectively address the challenges posed by COVID-19, it is essential to select appropriate animal models that can accurately replicate both fatal and non-fatal infections with varying courses and severities. Optimizing animal model libraries and associated research tools is key to resolving the global COVID-19 pandemic, serving as a robust resource for future emerging infectious diseases.

The transcriptome of MHV-infected RAW264.7 cells offers an alternative model for macrophage innate immunity research

BACKGROUND

Macrophages are the primary innate immune cells encountered by the invading coronaviruses, and their abilities to initiate inflammatory reactions, to maintain the immunity homeostasis by differential polarization, to train the innate immune system by epigenic modification have been reported in laboratory animal research.

METHODS

In the current in vitro research, murine macrophage RAW 264.7 cell were infected by mouse hepatitis virus, a coronavirus existed in mouse. At 3-, 6-, 12-, 24-, and 48-h post infection (hpi.), the attached cells were washed with PBS and harvested in Trizol reagent. Then The harvest is subjected to transcriptome sequencing.

RESULTS

The transcriptome analysis showed the immediate (3 hpi.) up regulation of DEGs related to inflammation, like Il1b and Il6. DEGs related to M2 differential polarization, like Irf4 showed up regulation at 24 hpi., the late term after viral infection. In addition, DEGs related to metabolism and histone modification, like Ezh2 were detected, which might correlate with the trained immunity of macrophages.

CONCLUSIONS

The current in vitro viral infection study showed the key innated immunity character of macrophages, which suggested the replacement value of viral infection cells model, to reduce the animal usage in preclinical research.

Prognosis of COVID-19 severity using DERGA, a novel machine learning algorithm

It is important to determine the risk for admission to the intensive care unit (ICU) in patients with COVID-19 presenting at the emergency department. Using artificial neural networks, we propose a new Data Ensemble Refinement Greedy Algorithm (DERGA) based on 15 easily accessible hematological indices. A database of 1596 patients with COVID-19 was used; it was divided into 1257 training datasets (80 % of the database) for training the algorithms and 339 testing datasets (20 % of the database) to check the reliability of the algorithms. The optimal combination of hematological indicators that gives the best prediction consists of only four hematological indicators as follows: neutrophil-to-lymphocyte ratio (NLR), lactate dehydrogenase, ferritin, and albumin. The best prediction corresponds to a particularly high accuracy of 97.12 %. In conclusion, our novel approach provides a robust model based only on basic hematological parameters for predicting the risk for ICU admission and optimize COVID-19 patient management in the clinical practice.

An antibody to IL-1 receptor 7 protects mice from LPS-induced tissue and systemic inflammation

Introduction

Interleukin-18 (IL-18), a pro-inflammatory cytokine belonging to the IL-1 Family, is a key mediator ofautoinflammatory diseases associated with the development of macrophage activation syndrome (MAS).High levels of IL-18 correlate with MAS and COVID-19 severity and mortality, particularly in COVID-19patients with MAS. As an inflammation inducer, IL-18 binds its receptor IL-1 Receptor 5 (IL-1R5), leadingto the recruitment of the co-receptor, IL-1 Receptor 7 (IL-1R7). This heterotrimeric complex subsequentlyinitiates downstream signaling, resulting in local and systemic inflammation.

Methods

We reported earlier the development of a novel humanized monoclonal anti-human IL-1R7 antibody whichspecifically blocks the activity of human IL-18 and its inflammatory signaling in human cell and wholeblood cultures. In the current study, we further explored the strategy of blocking IL-1R7 inhyperinflammation in vivo using animal models.

Results

We first identified an anti-mouse IL-1R7 antibody that significantly suppressed mouse IL-18 andlipopolysaccharide (LPS)-induced IFNg production in mouse splenocyte and peritoneal cell cultures. Whenapplied in vivo, the antibody reduced Propionibacterium acnes and LPS-induced liver injury and protectedmice from tissue and systemic hyperinflammation. Importantly, anti-IL-1R7 significantly inhibited plasma,liver cell and spleen cell IFNg production. Also, anti-IL-1R7 downregulated plasma TNFa, IL-6, IL-1b,MIP-2 production and the production of the liver enzyme ALT. In parallel, anti-IL-1R7 suppressed LPSinducedinflammatory cell infiltration in lungs and inhibited the subsequent IFNg production andinflammation in mice when assessed using an acute lung injury model.

Discussion

Altogether, our data suggest that blocking IL-1R7 represents a potential therapeutic strategy to specificallymodulate IL-18-mediated hyperinflammation, warranting further investigation of its clinical application intreating IL-18-mediated diseases, including MAS and COVID-19.

Macrophage Activation Syndrome in Viral Sepsis

Macrophage activation syndrome (MAS) is a life-threatening systemic hyperinflammatory syndrome triggered by various infections, particularly viral infections, autoimmune disorders, and malignancy. The condition is characterized by an increased production of proinflammatory cytokines resulting in a cytokine storm and has been associated with poor clinical outcomes. During the COVID-19 pandemic, patients with severe manifestations developed features similar to those of MAS, although these characteristics remained well defined within the lung. Additionally, other viral infections including EBV, the herpes family of viruses, hepatitis viruses, influenza, HIV, and hemorrhagic fevers can be complicated by MAS. The diagnosis and management of the condition remain challenging due to the lack of consensus on specific guidelines, especially among the adult population. Currently, therapeutic options primarily rely on medications that are typically used to treat primary hemophagocytic lymphohistiocytosis, such as corticosteroids and etoposide. In addition, cytokine-targeted therapies present promising treatment options. The objective of this review is to discuss the emergence of MAS in the context of viral infections including, but not limited to, its occurrence in COVID-19.

CT semi-quantitative score used as risk factor for hyponatremia in patients with COVID-19: a cross-sectional study

Purpose

Chest computed tomography (CT) is used to determine the severity of COVID-19 pneumonia, and pneumonia is associated with hyponatremia. This study aims to explore the predictive value of the semi-quantitative CT visual score for hyponatremia in patients with COVID-19 to provide a reference for clinical practice.

Methods

In this cross-sectional study, 343 patients with RT-PCR confirmed COVID-19, all patients underwent CT, and the severity of lung lesions was scored by radiologists using the semi-quantitative CT visual score. The risk factors of hyponatremia in COVID-19 patients were analyzed and combined with laboratory tests. The thyroid function changes caused by SARS-CoV-2 infection and their interaction with hyponatremia were also analyzed.

Results

In patients with SARS-CoV-2 infection, the total severity score (TSS) of hyponatremia was higher [M(range), 3.5(2.5-5.5) vs 3.0(2.0-4.5) scores, P=0.001], implying that patients with hyponatremia had more severe lung lesions. The risk factors of hyponatremia in the multivariate regression model included age, vomiting, neutrophils, platelet, and total severity score. SARS-CoV-2 infection impacted thyroid function, and patients with hyponatremia showed a lower free triiodothyronine (3.1 ± 0.9 vs 3.7 ± 0.9, P=0.001) and thyroid stimulating hormone level [1.4(0.8-2.4) vs 2.2(1.2-3.4), P=0.038].

Conclusion

Semi-quantitative CT score can be used as a risk factor for hyponatremia in patients with COVID-19. There is a weak positive correlation between serum sodium and free triiodothyronine in patients with SARS-CoV-2 infection.

SARS-CoV-2: pathogenesis, therapeutics, variants, and vaccines

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in December 2019 with staggering economic fallout and human suffering. The unique structure of SARS-CoV-2 and its underlying pathogenic mechanism were responsible for the global pandemic. In addition to the direct damage caused by the virus, SARS-CoV-2 triggers an abnormal immune response leading to a cytokine storm, culminating in acute respiratory distress syndrome and other fatal diseases that pose a significant challenge to clinicians. Therefore, potential treatments should focus not only on eliminating the virus but also on alleviating or controlling acute immune/inflammatory responses. Current management strategies for COVID-19 include preventative measures and supportive care, while the role of the host immune/inflammatory response in disease progression has largely been overlooked. Understanding the interaction between SARS-CoV-2 and its receptors, as well as the underlying pathogenesis, has proven to be helpful for disease prevention, early recognition of disease progression, vaccine development, and interventions aimed at reducing immunopathology have been shown to reduce adverse clinical outcomes and improve prognosis. Moreover, several key mutations in the SARS-CoV-2 genome sequence result in an enhanced binding affinity to the host cell receptor, or produce immune escape, leading to either increased virus transmissibility or virulence of variants that carry these mutations. This review characterizes the structural features of SARS-CoV-2, its variants, and their interaction with the immune system, emphasizing the role of dysfunctional immune responses and cytokine storm in disease progression. Additionally, potential therapeutic options are reviewed, providing critical insights into disease management, exploring effective approaches to deal with the public health crises caused by SARS-CoV-2.

Clinical Characteristics and Outcomes of Pediatric COVID-19 Pneumonia Treated with Favipiravir in a Tertiary Care Center

The COVID-19 pandemic, caused by SARS-CoV-2, has posed significant health challenges worldwide. While children generally experience less severe illness compared to adults, pneumonia remains a substantial risk, particularly for those under five years old. This study examines the clinical characteristics and treatment outcomes of pediatric COVID-19 pneumonia patients treated with favipiravir in Thailand, aiming to identify associated factors for pneumonia. A retrospective review was performed on pediatric patients aged 1 month to 18 years hospitalized with COVID-19 at Srinagarind Hospital, Khon Kaen University, from 13 January 2020 to 15 November 2021. Data on demographics, clinical symptoms, treatment, and outcomes were collected, and logistic regression analysis was used to identify factors associated with pneumonia. Among 349 hospitalized children, the median age was 8 years, with 51.9% being male. Symptoms included a fever (100%), a cough (74.2%), and a rash (24.9%). COVID-19 pneumonia was diagnosed in 54.7% of the children. Favipiravir was administered as the standard treatment, showing mild adverse effects, including a rash (4.3%) and nausea (2.8%). Monocytosis was significantly associated with COVID-19 pneumonia (aOR 30.85, 95% CI: 9.03-105.41, p < 0.001), with an ROC curve area of 0.77 (95% CI: 0.71-0.83). Pediatric COVID-19 patients typically exhibit mild-to-moderate symptoms, with pneumonia being common in the early pandemic phase. Monocytosis is a significant factor associated with COVID-19 pneumonia. Favipiravir demonstrated mild adverse effects. Further studies are needed to validate these findings across different settings and phases of the pandemic.

Predictive biomarkers of COVID-19 prognosis identified in Bangladesh patients and validated in Japanese cohorts

Despite high vaccination rates globally, countries are still grappling with new COVID infections, and patients diagnosed as mild dying at home during outpatient treatment. Hence, this study aim to identify, then validate, biomarkers that could predict if newly infected COVID-19 patients would subsequently require hospitalization or could recover safely with medication as outpatients. Serum cytokine/chemokine data from 129 COVID-19 patients within 7 days after the onset of symptoms in Bangladesh were used as training data. The majority of patients were infected with the Omicron variant and over 88% were vaccinated. Patients were divided into those with mild symptoms who recovered, and those who deteriorated to moderate or severe illness. Using the Lasso method, 15 predictive markers were identified and used to classify patients into these two groups. The biomarkers were then validated in a cohort of 194 Covid patients in Japan with a predictive accuracy that exceeded 80% for patients infected with Delta and Omicron variants, and 70% for Wuhan and Alpha variants. In an environment of widespread vaccination, these biomarkers could help medical practitioners determine if newly infected COVID-19 patients will improve and can be managed on an out-patient basis, or if they will deteriorate and require hospitalization.

Long COVID Definition, Symptoms, Risk Factors, Epidemiology and Autoimmunity: A Narrative Review

The virus called SARS-CoV-2 emerged in 2019 and quickly spread worldwide, causing COVID-19. It has greatly impacted on everyday life, healthcare systems, and the global economy. In order to save as many lives as possible, precautions such as social distancing, quarantine, and testing policies were implemented, and effective vaccines were developed. A growing amount of data collected worldwide allowed the characterization of this new disease, which turned out to be more complex than other common respiratory tract infections. An increasing number of convalescents presented with a variety of nonspecific symptoms emerging after the acute infection. This possible new global health problem was identified and labelled as long COVID. Since then, a great effort has been made by clinicians and the scientific community to understand the underlying mechanisms and to develop preventive measures and effective treatment. The role of autoimmunity induced by SARS-CoV-2 infection in the development of long COVID is discussed in this review. We aim to deliver a description of several conditions with an autoimmune background observed in COVID-19 convalescents, including Guillain-Barré syndrome, antiphospholipid syndrome and related thrombosis, and Kawasaki disease highlighting a relationship between SARS-CoV-2 infection and the development of autoimmunity. However, further studies are required to determine its true clinical significance.

Understanding long COVID myocarditis: A comprehensive review

Infectious diseases are a cause of major concern in this twenty-first century. There have been reports of various outbreaks like severe acute respiratory syndrome (SARS) in 2003, swine flu in 2009, Zika virus disease in 2015, and Middle East Respiratory Syndrome (MERS) in 2012, since the start of this millennium. In addition to these outbreaks, the latest infectious disease to result in an outbreak is the SARS-CoV-2 infection. A viral infection recognized as a respiratory illness at the time of emergence, SARS-CoV-2 has wreaked havoc worldwide because of its long-lasting implications like heart failure, sepsis, organ failure, etc., and its significant impact on the global economy. Besides the acute illness, it also leads to symptoms months later which is called long COVID or post-COVID-19 condition. Due to its ever-increasing prevalence, it has been a significant challenge to treat the affected individuals and manage the complications as well. Myocarditis, a long-term complication of coronavirus disease 2019 (COVID-19) is an inflammatory condition involving the myocardium of the heart, which could even be fatal in the long term in cases of progression to ventricular dysfunction and heart failure. Thus, it is imperative to diagnose early and treat this condition in the affected individuals. At present, there are numerous studies which are in progress, investigating patients with COVID-19-related myocarditis and the treatment strategies. This review focuses primarily on myocarditis, a life-threatening complication of COVID-19 illness, and endeavors to elucidate the pathogenesis, biomarkers, and management of long COVID myocarditis along with pipeline drugs in detail.

Pathology of COVID-19 Lung Disease

The pathology of severe COVID-19 lung injury is predominantly diffuse alveolar damage, with other reported patterns including acute fibrinous organizing pneumonia, organizing pneumonia, and bronchiolitis. Lung injury was caused by primary viral injury, exaggerated immune responses, and superinfection with bacteria and fungi. Although fatality rates have decreased from the early phases of the pandemic, persistent pulmonary dysfunction occurs and its pathogenesis remains to be fully elucidated.

Does sex modify the effect of pre-pandemic body mass index on the risk of Long COVID? Evidence from the longitudinal analysis of the Survey of Health, Ageing and Retirement in Europe

BACKGROUND

Research on Long COVID risk factors is ongoing. High body mass index (BMI) may increase Long COVID risk, yet no evidence has been established regarding sex differences in the relationship between BMI and the risk of Long COVID. Investigating the nature of this relationship was the main objective of this study.

METHODS

A population-based prospective study involving a sample of respondents aged 50 years and older (n = 4004) from 27 European countries that participated in the 2020 and 2021 Survey of Health, Ageing and Retirement in Europe's (SHARE) Corona Surveys and in Waves 7 and 8 of the main SHARE survey. Logistic regression models were estimated to produce unadjusted and adjusted estimates of the sex differences in the relationship between BMI and Long COVID.

RESULTS

Linear relationship for females, with probability of Long COVID increasing with BMI (68% at BMI = 18, 93% at BMI = 45). Non-linear relationship for males, with probability of Long COVID of 27% at BMI = 18, 68% at BMI = 33, and 40% at BMI = 45. Relationships remained significant after adjusting for known Long COVID risk factors (age and COVID-19 hospitalization), presence of chronic diseases, and respondents' place of residence.

CONCLUSION

Sex differences appear to play an important role in the relationship between BMI and risk of Long COVID. Overall, females were more likely to have Long COVID, regardless of their BMI. Males at the higher end of the BMI spectrum had a lower risk of Long COVID as opposed to their female counterparts. Sex-specific research is recommended for better understanding of Long COVID risk factors.

Vascular endothelial-derived SPARCL1 exacerbates viral pneumonia through pro-inflammatory macrophage activation

Inflammation induced by lung infection is a double-edged sword, moderating both anti-viral and immune pathogenesis effects; the mechanism of the latter is not fully understood. Previous studies suggest the vasculature is involved in tissue injury. Here, we report that expression of Sparcl1, a secreted matricellular protein, is upregulated in pulmonary capillary endothelial cells (EC) during influenza-induced lung injury. Endothelial overexpression of SPARCL1 promotes detrimental lung inflammation, with SPARCL1 inducing 'M1-like' macrophages and related pro-inflammatory cytokines, while SPARCL1 deletion alleviates these effects. Mechanistically, SPARCL1 functions through TLR4 on macrophages in vitro, while TLR4 inhibition in vivo ameliorates excessive inflammation caused by endothelial Sparcl1 overexpression. Finally, SPARCL1 expression is increased in lung ECs from COVID-19 patients when compared with healthy donors, while fatal COVID-19 correlates with higher circulating SPARCL1 protein levels in the plasma. Our results thus implicate SPARCL1 as a potential prognosis biomarker for deadly COVID-19 pneumonia and as a therapeutic target for taming hyperinflammation in pneumonia.

HIGH THROUGHPUT QUANTITATION OF HUMAN NEUTROPHIL RECRUITMENT AND FUNCTIONAL RESPONSES IN AN AIR-BLOOD BARRIER ARRAY

Dysregulated neutrophil recruitment drives many pulmonary diseases, but most preclinical screening methods are unsuited to evaluate pulmonary neutrophilia, limiting progress towards therapeutics. Namely, high throughput therapeutic screening systems typically exclude critical neutrophilic pathophysiology, including blood-to-lung recruitment, dysfunctional activation, and resulting impacts on the air-blood barrier. To meet the conflicting demands of physiological complexity and high throughput, we developed an assay of 96-well Leukocyte recruitment in an Air-Blood Barrier Array (L-ABBA-96) that enables in vivo -like neutrophil recruitment compatible with downstream phenotyping by automated flow cytometry. We modeled acute respiratory distress syndrome (ARDS) with neutrophil recruitment to 20 ng/mL epithelial-side interleukin 8 (IL-8) and found a dose dependent reduction in recruitment with physiologic doses of baricitinib, a JAK1/2 inhibitor recently FDA-approved for severe COVID-19 ARDS. Additionally, neutrophil recruitment to patient-derived cystic fibrosis sputum supernatant induced disease-mimetic recruitment and activation of healthy donor neutrophils and upregulated endothelial e-selectin. Compared to 24-well assays, the L-ABBA-96 reduces required patient sample volumes by 25 times per well and quadruples throughput per plate. Compared to microfluidic assays, the L-ABBA-96 recruits two orders of magnitude more neutrophils per well, enabling downstream flow cytometry and other standard biochemical assays. This novel pairing of high-throughput in vitro modeling of organ-level lung function with parallel high-throughput leukocyte phenotyping substantially advances opportunities for pathophysiological studies, personalized medicine, and drug testing applications.

The causal relationship between COVID-19 and ten esophageal diseases: a study utilizing Mendelian randomization

Background

Clinical signs of dysphagia, pancreatic achalasia, and esophagitis have been reported in patients with COVID-19. However, the causal relationship between COVID-19 and esophageal diseases is not clear. Therefore, we utilized Mendelian randomization to explore the potential association between COVID-19 and esophageal diseases.

Methods

The summary statistics for a Genome-wide association study (GWAS) were obtained from The COVID-19 Host Genetics Initiative, encompassing four types of COVID-19 as exposure: severe COVID-19, hospitalized COVID-19 versus ambulatory COVID-19, hospitalized COVID-19 versus uninfected, and confirmed COVID-19. Additionally, summary statistics for ten esophageal diseases as outcomes were sourced from the GWAS Catalog and FinnGen databases. Univariate Mendelian randomization (MR) analysis was utilized to thoroughly investigate and validate the potential causal association between COVID-19 and various esophageal conditions, including esophageal varices, Barrett's esophagus, esophagitis, esophageal obstruction, esophageal ulcer, esophageal perforation, gastroesophageal reflux, congenital esophageal malformations, benign esophageal tumors, and esophageal adenocarcinoma.

Results

An inverse variance-weighted (IVW) model was utilized for univariate Mendelian randomization (MR) analysis, which revealed that genetic liability in patients with confirmed COVID-19 was associated with esophageal obstruction (OR [95% CI]: 0.5275458 [0.2822400-0.9860563]; p-value = 0.0450699). Furthermore, a suggestive causal association was found between genetic liability and a reduced risk of benign esophageal tumors (OR [95% CI]: 0.2715453 [0.09368493-0.7870724]; p-value = 0.0163510), but with a suggestively increased risk of congenital esophageal malformations (OR [95% CI]: 6.959561 [1.1955828-40.51204]; p-value = 0.03086835). Additionally, genetic liability in hospitalized COVID-19 patients, compared to non-hospitalized COVID-19 patients, was suggestively associated with an increased risk of esophagitis (OR [95% CI]: 1.443859 [1.0890568-1.914252]; p-value = 0.01068201). The reliability of these causal findings is supported by Cochran's Q statistic and the MR-Egger intercept test.

Conclusion

The results of this study suggest the existence of a causal relationship between COVID-19 and esophageal diseases, highlighting differing risk effects of COVID-19 on distinct esophageal conditions.

Occurrence of COVID-19 in cystic fibrosis patients: a review

Cystic fibrosis (CF) is a genetic ailment caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This autosomal recessive disorder is characterized by diverse pathobiological abnormalities, such as the disorder of CFTR channels in mucosal surfaces, caused by inadequate clearance of mucus and sputum, in addition to the malfunctioning of mucous organs. However, the primary motive of mortality in CF patients is pulmonary failure, which is attributed to the colonization of opportunistic microorganisms, formation of resistant biofilms, and a subsequent decline in lung characteristics. In December 2019, the World Health Organization (WHO) declared the outbreak of the radical coronavirus disease 2019 (COVID-19) as a worldwide public health crisis, which unexpectedly spread not only within China but also globally. Given that the respiration system is the primary target of the COVID-19 virus, it is crucial to investigate the impact of COVID-19 on the pathogenesis and mortality of CF patients, mainly in the context of acute respiratory distress syndrome (ARDS). Therefore, the goal of this review is to comprehensively review the present literature on the relationship between cystic fibrosis, COVID-19 contamination, and development of ARDS. Several investigations performed during the early stages of the virus outbreak have discovered unexpected findings regarding the occurrence and effectiveness of COVID-19 in individuals with CF. Contrary to initial expectancies, the rate of infection and the effectiveness of the virus in CF patients are lower than those in the overall population. This finding may be attributed to different factors, including the presence of thick mucus, social avoidance, using remedies that include azithromycin, the fairly younger age of CF patients, decreased presence of ACE-2 receptors, and the effect of CFTR channel disorder on the replication cycle and infectivity of the virus. However, it is important to notice that certain situations, which include undergoing a transplant, can also doubtlessly boost the susceptibility of CF patients to COVID-19. Furthermore, with an increase in age in CF patients, it is vital to take into account the prevalence of the SARS-CoV-2 virus in this population. Therefore, ordinary surveillance of CF patients is vital to evaluate and save the population from the capability of transmission of the virus given the various factors that contribute to the spread of the SARS-CoV-2 outbreak in this precise organization.

Pulmonary embolism impacts clinical outcomes of intubated patients with acute respiratory distress syndrome related to COVID-19

BACKGROUND

Pulmonary embolism (PE) in critically ill patients with acute respiratory distress syndrome (ARDS) caused by COVID-19 is a major complication which might impact survival. We aimed to determine the prevalence of PE and assess its impact of PE on clinical outcomes in intubated patients with ARDS due to COVID-19.

METHODS

All intubated patients with ARDS due to COVID-19 admitted to the intensive care unit (ICU) of Geneva University Hospitals between March 9, 2020, and May 31, 2022, were included. A retrospective analysis was conducted on the occurrence of PE and its association with clinical outcomes. The primary outcome was ventilator-free days during the first 28 days after ICU admission. Linear regressions were performed to investigate the association between PE and outcomes.

RESULTS

Among the 370 intubated patients with ARDS related to COVID-19, 58 (15.7%) presented with PE. Patients with PE had significantly fewer ventilator-free days than patients without PE (median (IQR) of 3 (0-11) days versus 12 (0-19) days; p < 0.001). Mortality did not differ significantly between groups (12/58 [20.7%] of patients with PE versus 71/312 [22.8%] of patients without PE; p = 0.72). Duration of IMV, and ICU and hospital LOS were significantly longer among patients with PE. The need for ECMO support was similar among both groups.

CONCLUSIONS

The occurrence of PE in patients with ARDS due to COVID-19 had a significant impact on clinical outcomes. They had fewer ventilator-free days, longer duration of IMV, and longer ICU and hospital lengths of stay. However, pulmonary embolism was not associated with higher mortality.

ETHICS APPROVAL

Ethical committee of Geneva (BASEC #: 2020-00917).

Inflammasome-Related Genetic Polymorphisms as Severity Biomarkers of COVID-19

The most critical forms of coronavirus disease 2019 (COVID-19) are associated with excessive activation of the inflammasome. Despite the COVID-19 impact on public health, we still do not fully understand the mechanisms by which the inflammatory response influences disease prognosis. Accordingly, we aimed to elucidate the role of polymorphisms in the key genes of the formation and signaling of the inflammasome as biomarkers of COVID-19 severity. For this purpose, a large and well-defined cohort of 377 COVID-19 patients with mild (n = 72), moderate (n = 84), severe (n = 100), and critical (n = 121) infections were included. A total of 24 polymorphisms located in inflammasome-related genes (NLRP3, NLRC4, NLRP1, CARD8, CASP1, IL1B, IL18, NFKB1, ATG16L1, and MIF) were genotyped in all of the patients and in the 192 healthy controls (HCs) (who were without COVID-19 at the time of and before the study) by RT-qPCR. Our results showed that patients with mild, moderate, severe, and critical COVID-19 presented similar allelic and genotypic distribution in all the variants studied. No statistically significant differences in the haplotypic distribution of NLRP3, NLRC4, NLRP1, CARD8, CASP1, IL1B, and ATG16L1 were observed between COVID-19 patients, who were stratified by disease severity. Each stratified group of patients presented a similar genetic distribution to the HCs. In conclusion, our results suggest that the inflammasome polymorphisms studied are not associated with the worsening of COVID-19.

Point-of-care lung ultrasound predicts hyperferritinemia and hospitalization, but not elevated troponin in SARS-CoV-2 viral pneumonitis in children

SARS-CoV-2 often causes viral pneumonitis, hyperferritinemia, elevations in D-dimer, lactate dehydrogenase (LDH), transaminases, troponin, CRP, and other inflammatory markers. Lung ultrasound is increasingly used to diagnose and stratify viral pneumonitis severity. We retrospectively reviewed 427 visits in patients aged 14 days to 21 years who had had a point-of-care lung ultrasound in our pediatric emergency department from 30/November/2019 to 14/August/2021. Lung ultrasounds were categorized using a 6-point ordinal scale. Lung ultrasound abnormalities predicted increased hospitalization with a threshold effect. Increasingly abnormal laboratory values were associated with decreased discharge from the ED and increased admission to the ward and ICU. Among patients SARS-CoV-2 positive patients ferritin, LDH, and transaminases, but not CRP or troponin were significantly associated with abnormalities on lung ultrasound and also with threshold effects. This effect was not demonstrated in SARS-CoV-2 negative patients. D-Dimer, CRP, and troponin were sometimes elevated even when the lung ultrasound was normal.

Association of soluble PD-L1 and NLR combination with 1-Year mortality in patients with COVID-19

PURPOSE

Understanding the relationship between patient immune characteristics, disease severity, and mortality represents a critical step in the fight against COVID-19. Elevated levels of programmed death ligand-1 (PD-L1) and Neutrophil-lymphocyte ratio (NLR) are linked to increased severity of acute COVID-19 in patients. This study aimed to investigate the association of the combination of sPD-L1 and NLR with 1-year Mortality in patients with COVID-19.

METHODS

A prospective study was conducted involving patients with COVID-19 in Karaganda, Kazakhstan. The level of sPD-L1 in the blood serum was evaluated by ELISA. The effect of biomarkers on the development of mortality was analyzed with multivariate regression.

RESULTS

The risk of mortality within one year HR was 2.46 if the plasma sPD-L1 value of more than 277.13 pg/ml, and for NLR more than 2.46 HR was 2.87. The model of combining sPD-L1 and NLR resulted in an improvement in the predictive accuracy of the Hazard Ratio 7.6 (95 % CI: 3.02-19.11).

CONCLUSION

The combination of two immune-mediated markers (sPD-L1 and NLR), which reflect the systemic inflammatory balance of activation and exhaustion, can complement each other and improve the assessment of the risk of death in patients with COVID-19.

Cardiac injury progression in children with multisystem inflammatory syndrome associated with SARS-CoV-2 infection: a review

The symptoms and signs of infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are milder in children than in adults. However, in April 2020, British pediatricians first reported that coronavirus disease 2019 (COVID-19) may present as multisystem inflammatory syndrome in children and adolescents (MIS-C), similar to that observed in Kawasaki disease. MIS-C can be associated with multiple systemic injuries and even death in children. In addition to digestive system involvement, cardiac injury is prominent. This article reviews the pathogenesis, clinical manifestations, and treatment of cardiac injury caused by MIS-C, which may help clinicians in early diagnosis and timely commencement of treatment.

Comparable safety and non-inferior immunogenicity of the SARS-CoV-2 mRNA vaccine candidate PTX-COVID19-B and BNT162b2 in a phase 2 randomized, observer-blinded study

In the aftermath of the COVID-19 pandemic, the evolution of the SARS-CoV-2 into a seasonal pathogen along with the emergence of new variants, underscores the need for dynamic and adaptable responses, emphasizing the importance of sustained vaccination strategies. This observer-blind, double-dummy, randomized immunobridging phase 2 study (NCT05175742) aimed to compare the immunogenicity induced by two doses of 40 μg PTX-COVID19-B vaccine candidate administered 28 days apart, with the response induced by two doses of 30 µg Pfizer-BioNTech COVID-19 vaccine (BNT162b2), administered 21 days apart, in Nucleocapsid-protein seronegative adults 18-64 years of age. Both vaccines were administrated via intramuscular injection in the deltoid muscle. Two weeks after the second dose, the neutralizing antibody (NAb) geometric mean titer ratio and seroconversion rate met the non-inferiority criteria, successfully achieving the primary immunogenicity endpoints of the study. PTX-COVID19-B demonstrated similar safety and tolerability profile to BNT162b2 vaccine. The lowest NAb response was observed in subjects with low-to-undetectable NAb at baseline or no reported breakthrough infection. Conversely, participants who experienced breakthrough infections during the study exhibited higher NAb titers. This study also shows induction of cell-mediated immune (CMI) responses by PTX-COVID19-B. In conclusion, the vaccine candidate PTX-COVID19-B demonstrated favourable safety profile along with immunogenicity similar to the active comparator BNT162b2 vaccine.

Global Perspective on COVID-19 Therapies, Cardiovascular Outcomes, and Implications for Long COVID: A State-of-the-Art Review

The COVID-19 pandemic has resulted in many therapies, of which many are repurposed and used for other diseases in the last decade such in Influenza and Ebola. We intend to provide a robust foundation for cardiovascular outcomes of the therapies to better understand the rationale for the clinical trials that were conducted during the COVID-19 pandemic, and to gain more clarity on the steps moving forward should the repurposing provide clinical benefit in pandemic situations. With this state-of-the-art review, we aim to improve the understanding of the cardiovascular involvement of the therapies prior to, during, and after the COVID-19 pandemic to provide meaningful findings to the cardiovascular specialists and clinical trials for therapies, moving on from the period of pandemic urgency.

Cardiac arrhythmia in COVID-19 patients

The coronavirus disease 2019 (COVID-19) was first introduced in December 2019, which is known as severe acute respiratory syndrome caused by coronavirus-2 (SARS-CoV-2) that is a serious and life-threatening disease. Although pneumonia is the most common manifestation of COVID-19 and was initially introduced as a respiratory infection, in fact, the infection of COVID-19 is a subset of complications and damage to various organs. There are several reports of cardiac involvement with COVID-19. A wide range of cardiac complications may occur following COVID-19 infection, including systolic heart failure, myocarditis, pericarditis, atrial and ventricular arrhythmias, and thromboembolic events. There are various hypotheses about the pathophysiology of cardiovascular involvement by this virus. At the top of these hypotheses is the release of cytokines to the heart. Although there are other assumptions, considering that one of the causes of death in patients with COVID-19 is arrhythmia. It is necessary to know correctly about its pathophysiology and etiology. Therefore, in this study, we have reviewed the articles of recent years in the field of pathophysiology and etiology of arrhythmia in patients with COVID-19 infection. The purpose of this study was to provide a basis for a correct and more comprehensive understanding of the pathogenesis of arrhythmia in patients with COVID-19 infection.

Pharmacological induction of autophagy reduces inflammation in macrophages by degrading immunoproteasome subunits

Defective autophagy is linked to proinflammatory diseases. However, the mechanisms by which autophagy limits inflammation remain elusive. Here, we found that the pan-FGFR inhibitor LY2874455 efficiently activated autophagy and suppressed expression of proinflammatory factors in macrophages stimulated by lipopolysaccharide (LPS). Multiplex proteomic profiling identified the immunoproteasome, which is a specific isoform of the 20s constitutive proteasome, as a substrate that is degraded by selective autophagy. SQSTM1/p62 was found to be a selective autophagy-related receptor that mediated this degradation. Autophagy deficiency or p62 knockdown blocked the effects of LY2874455, leading to the accumulation of immunoproteasomes and increases in inflammatory reactions. Expression of proinflammatory factors in autophagy-deficient macrophages could be reversed by immunoproteasome inhibitors, confirming the pivotal role of immunoproteasome turnover in the autophagy-mediated suppression on the expression of proinflammatory factors. In mice, LY2874455 protected against LPS-induced acute lung injury and dextran sulfate sodium (DSS)-induced colitis and caused low levels of proinflammatory cytokines and immunoproteasomes. These findings suggested that selective autophagy of the immunoproteasome was a key regulator of signaling via the innate immune system.

Lymphopenia associated with survivin and its downstream pathway in COVID-19 serving as a potential route in COVID-19 pathogenesis

PURPOSE

Starting in 2019, coronavirus disease 2019 (COVID-19) caused an epidemic that was growing rapidly and has harmed millions of people globally. It has been demonstrated that survivin regulates lymphocyte survival, a main route involved in COVID-19 pathogenesis. Survivin belongs to the inhibitor of apoptosis protein (IAP) family, and its primary functions comprise regulating mitosis and inhibiting apoptosis. Since lower survivin expression has been shown to increase the sensitivity of lymphocytes to apoptotic induction, we looked into the function of survivin and its corresponding pathways in COVID-19 pathogenesis.

MATERIALS AND METHODS

The expression of survivin, X-linked inhibitor of apoptosis protein (XIAP), caspases 3, 7, 9, and poly (ADP-ribose) polymerase (PARP) was evaluated at both mRNA and protein levels in peripheral blood mononuclear cells (PBMCs) derived from healthy donors and patients with severe and moderate COVID-19 by qRT-PCR and Western blotting, respectively. Then, we enforced apoptosis to COVID-19 patient-derived lymphocytes, and the percent was assessed by flow cytometry.

RESULTS

Survivin and XIAP were less expressed in PBMCs derived from COVID-19 patients as apoptosis inhibitors than PARP, cleaved-PARP, caspase 9, and cleaved caspases 3 and 7, according to the results of real-time PCR and Western blot analysis. Additionally, according to the flow cytometry results, the down-regulation of survivin served as a potential factor in the lymphocyte depletion observed in patients with COVID-19.

CONCLUSION

The role of survivin and its related pathway was first discovered in the development of COVID-19 and may serve as a potential prognostic and therapeutic target.

Mystery of COVID 19: Focusing on important ncRNAs and effective signaling pathways

This article provides a thorough investigation of the essential role of non-coding RNAs (ncRNAs) in the context of COVID-19, emphasizing their impact on the complex molecular dynamics of the viral infection. By conducting a systematic review of existing literature, we identify key ncRNAs involved in different stages of the viral life cycle, modulation of host immune response, and disease progression. The importance of microRNAs, long non-coding RNAs, and other ncRNA types emerges as influential factors in shaping the interaction between the host and the virus. Additionally, the study delves into the effective signaling pathways linked to COVID-19 pathogenesis, uncovering intricate molecular cascades that govern viral entry, replication, and host cell response. This exploration encompasses established pathways such as IL-6/JAK/STAT signaling, highlighting their interplay within the context of COVID-19. By synthesizing this knowledge, our aim is not only to enhance our understanding of the molecular complexities of COVID-19 but also to reveal potential therapeutic targets. Through elucidating the interaction between ncRNAs and signaling pathways, our article seeks to contribute to ongoing efforts in developing targeted interventions against COVID-19, ultimately advancing our ability to address this global health crisis.

A multicentre, double-blind, placebo-controlled randomized trial of Mycobacterium w in critically ill patients with COVID-19 (ARMY-2)

BACKGROUND

Mycobacterium w (Mw), an immunomodulator, resulted in better clinical status in severe coronavirus infectious disease 19 (COVID-19) but no survival benefit in a previous study. Herein, we investigate whether Mw could improve clinical outcomes and survival in COVID-19.

MATERIALS AND METHODS

In a multicentric, randomized, double-blind, parallel-group, placebo-controlled trial, we randomized hospitalized subjects with severe COVID-19 to receive either 0.3 mL/day of Mw intradermally or a matching placebo for three consecutive days. The primary outcome was 28-day mortality. The co-primary outcome was the distribution of clinical status assessed on a seven-point ordinal scale ranging from discharged (category 1) to death (category 7) on study days 14, 21, and 28. The key secondary outcomes were the change in sequential organ failure assessment (SOFA) score on days 7 and 14 compared to the baseline, treatment-emergent adverse events, and others.

RESULTS

We included 273 subjects (136 Mw, 137 placebo). The use of Mw did not improve 28-day survival (Mw vs. placebo, 18 [13.2%] vs. 12 [8.8%], P = 0.259) or the clinical status on days 14 (odds ratio [OR], 1.33; 95% confidence intervals [CI], 0.79-2.3), 21 (OR, 1.49; 95% CI, 0.83-2.7) or 28 (OR, 1.49; 95% CI, 0.79-2.8) between the two study arms. There was no difference in the delta SOFA score or other secondary outcomes between the two groups. We observed higher injection site reactions with Mw.

CONCLUSION

Mw did not reduce 28-day mortality or improve clinical status on days 14, 21 and 28 compared to placebo in patients with severe COVID-19. [Trial identifier: CTRI/2020/04/024846].

Antibodies against SARS-CoV-2 non-structural protein 3 cross-react with human muscle cells and neuroglial cells

Coronavirus Disease 2019 (COVID-19) vaccines protect the public and limit viral spread. However, inactivated viral vaccines use the whole virus particle, which contains many non-capsid proteins that may cause adverse immune responses. A report has found that the ADP-ribose-binding domains of SARS-CoV-2 non-structural protein 3 (NSP3) and human poly(ADP-ribose) polymerase family member 14 (PARP14) share a significant degree of homology. Here, we further show that antibodies against 2019 novel SARS-like coronavirus (SARS-CoV-2) NSP3 can bind human PARP14 protein. However, when G159R + G162R mutations were introduced into NSP3, the antibody titer against human PARP14 decreased 14-fold. Antibodies against SARS-CoV-2 NSP3 can cross-react with human skeletal muscle cells and astrocytes, but not human embryonic kidney 293T cells. However, when G159R + G162R mutations were introduced into NSP3, the cross-reaction was largely inhibited. The results imply that COVID-19 patients with high antibody titers against NSP3 may have high risks of muscular and/or neurological complications. And the possible strategies to improve the safety of inactivated viral vaccines are also discussed.

Muscle Dysfunction and Functional Status in COVID-19 Patients during Illness and after Hospital Discharge

BACKGROUND

COVID-19 pneumonia is associated with SIRS and hypercatabolism. The aim of this study was to determine muscle loss during the acute phase of COVID-19 pneumonia and evaluate long-term sequelae in discharged patients.

METHODS

A total of 16 patients with COVID-19 pneumonia and respiratory insufficiency were included in the study. Selected parameters (weight, BMI, LBM = lean body mass, albumin, CRP, NLR = neutrophil-to-lymphocyte ratio, ultrasound measured thickness of rectus femoris muscle = US RF and rectus femoris + vastus intermedius = US RF + VI, handgrip strength, quality of life = EQ-5D questionnaire, and activities of daily living = Barthel's ADLs) were recorded on admission, discharge, and 1, 3, and 6 months after discharge.

RESULTS

The most significant changes were between hospital admission and discharge: US RF and RF + VI (-1.28 ± 1.97 mm, p = 0.046; -1.76 ± 2.94 mm, p = 0.05), EQ-5D score (14.6 ± 19.2, p = 0.02), and ADLs (17.1 ± 22.6; p = 0.02). There was a significant positive correlation between US RF + VI and handgrip strength (p = 0.014) and a negative correlation between weight and Barthel index (p = 0.012). There was an association between muscle function with an EQ-5D score and ADLs during outpatient check-ups, most noticeably between handgrip strength, US RF+VI, and ADLs (p = 0.08; p = 0.1, respectively). Conclusions: In patients with COVID-19 pneumonia, there is a significant reduction of health-related quality of life, impaired even 6 months after hospital discharge, influenced mainly by muscle loss. During the hospital stay, there was a significant muscle mass reduction. Ultrasound measurement of thigh muscle thickness may be a useful method to monitor muscle loss.

COVID-19 in patients with anemia and haematological malignancies: risk factors, clinical guidelines, and emerging therapeutic approaches

Extensive research in countries with high sociodemographic indices (SDIs) to date has shown that coronavirus disease 2019 (COVID-19) may be directly associated with more severe outcomes among patients living with haematological disorders and malignancies (HDMs). Because individuals with moderate to severe immunodeficiency are likely to undergo persistent infections, shed virus particles for prolonged periods, and lack an inflammatory or abortive phase, this represents an overall risk of morbidity and mortality from COVID-19. In cases suffering from HDMs, further investigation is needed to achieve a better understanding of triviruses and a group of related variants in patients with anemia and HDMs, as well as their treatment through vaccines, drugs, and other methods. Against this background, the present study aimed to delineate the relationship between HDMs and the novel COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides, effective treatment options for HDM cases were further explored to address this epidemic and its variants. Therefore, learning about how COVID-19 manifests in these patients, along with exploiting the most appropriate treatments, may lead to the development of treatment and care strategies by clinicians and researchers to help patients recover faster. Video Abstract.

Precision treatment of viral pneumonia through macrophage-targeted lipid nanoparticle delivery

Macrophages are integral components of the innate immune system, playing a dual role in host defense during infection and pathophysiological states. Macrophages contribute to immune responses and aid in combatting various infections, yet their production of abundant proinflammatory cytokines can lead to uncontrolled inflammation and worsened tissue damage. Therefore, reducing macrophage-derived proinflammatory cytokine release represents a promising approach for treating various acute and chronic inflammatory disorders. However, limited macrophage-specific delivery vehicles have hindered the development of macrophage-targeted therapies. In this study, we screened a pool of 112 lipid nanoparticles (LNPs) to identify an optimal LNP formulation for efficient siRNA delivery. Subsequently, by conjugating the macrophage-specific antibody F4/80 to the LNP surface, we constructed MacLNP, an enhanced LNP formulation designed for targeted macrophage delivery. In both in vitro and in vivo experiments, MacLNP demonstrated a significant enhancement in targeting macrophages. Specifically, delivery of siRNA targeting TAK1, a critical kinase upstream of multiple inflammatory pathways, effectively suppressed the phosphorylation/activation of NF-kB. LNP-mediated inhibition of NF-kB, a key upstream regulator in the classic inflammatory signaling pathway, in the murine macrophage cell line RAW264.7 significantly reduced the release of proinflammatory cytokines after stimulation with the viral RNA mimic Poly(I:C). Finally, intranasal administration of MacLNP-encapsulated TAK1 siRNA markedly ameliorated lung injury induced by influenza infection. In conclusion, our findings validate the potential of targeted macrophage interventions in attenuating inflammatory responses, reinforcing the potential of LNP-mediated macrophage targeting to treat pulmonary inflammatory disorders.

The Role of the Nuclear Factor-Kappa B (NF-κB) Pathway in SARS-CoV-2 Infection

COVID-19 is a global health threat caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is associated with a significant increase in morbidity and mortality. The present review discusses nuclear factor-kappa B (NF-κB) activation and its potential therapeutical role in treating COVID-19. COVID-19 pathogenesis, the major NF-κB pathways, and the involvement of NF-κB in SARS-CoV-2 have been detailed. Specifically, NF-κB activation and its impact on managing COVID-19 has been discussed. As a central player in the immune and inflammatory responses, modulating NF-κB activation could offer a strategic avenue for managing SARS-CoV-2 infection. Understanding the NF-κB pathway's role could aid in developing treatments against SARS-CoV-2. Further investigations into the intricacies of NF-κB activation are required to reveal effective therapeutic strategies for managing and combating the SARS-CoV-2 infection and COVID-19.

The association between tocilizumab and the secondary bloodstream infection maybe nonsignificant in hospitalized patients with SARS-CoV-2 infection: A cohort study

BACKGROUND

Immunomodulatory agents, such as tocilizumab (TCZ), exert promising effects against SARS-CoV-2 infection. However, growing evidence indicates that using TCZ may carry higher risks of secondary bloodstream infection (sBSI). This study determined whether TCZ is associated with an increased risk of sBSI.

METHODS

We retrospectively collected the demographic and clinical data of hospitalized patients with SARS-CoV-2 infection from two Taiwanese hospitals. The time-to-incident sBSI in the TCZ users and nonusers was compared using the log-rank test. A multivariate Cox proportional hazards model was performed to identify independent risk factors for sBSI.

RESULTS

Between May 1 and August 31, 2021, among 453 patients enrolled, 12 (2.65 %) developed sBSI. These patients were in hospital for longer duration (44.2 ± 31.4 vs. 17.6 ± 14.3 days, p = 0.014). Despite sBSI being more prevalent among the TCZ users (7.1 % vs. 1.6 %, p = 0.005), Kaplan-Meier survival analysis and multivariate Cox proportional hazards model both revealed no significant difference in risks of sBSI between the TCZ users and nonusers [adjusted HR (aHR) = 1.32 (95 % confidence interval (CI) = 0.29-6.05), p = 0.724]. Female sex [aHR = 7.00 (95 % CI = 1.45-33.92), p = 0.016], heavy drinking [aHR = 5.39 (95 % CI = 1.01-28.89), p = 0.049], and mechanical ventilation [aHR = 5.65 (95 % CI = 1.67-19.30), p = 0.006] were independently associated with a higher sBSI risk.

CONCLUSION

This real-world evidence indicates that in hospitalized patients with SARS-CoV-2 infection, TCZ does not significantly increase the risk of sBSI.

Regulation of Inflammation by IRAK-M Pathway Can Be Associated with nAchRalpha7 Activation and COVID-19

In spite of the vaccine development and its importance, the SARS-CoV-2 pandemic is still impacting the world. It is known that the COVID-19 severity is related to the cytokine storm phenomenon, being inflammation a common disease feature. The nicotinic cholinergic system has been widely associated with COVID-19 since it plays a protective role in inflammation via nicotinic receptor alpha 7 (nAchRalpha7). In addition, SARS-CoV-2 spike protein (Spro) subunits can interact with nAchRalpha7. Moreover, Spro causes toll-like receptor (TLR) activation, leading to pro- and anti-inflammatory pathways. The increase and maturation of the IL-1 receptor-associated kinase (IRAK) family are mediated by activation of membrane receptors, such as TLRs. IRAK-M, a member of this family, is responsible for negatively regulating the activity of other active IRAKs. In addition, IRAK-M can regulate microglia phenotype by specific protein expression. Furthermore, there exists an antagonist influence of SARS-CoV-2 Spro and the cholinergic system action on the IRAK-M pathway and microglia phenotype. We discuss the overexpression and suppression of IRAK-M in inflammatory cell response to inflammation in SARS-CoV-2 infection when the cholinergic system is constantly activated via nAchRalpha7.

Characteristics of COVID-19 and Impact of Disease Activity in Patients with Adult-Onset Still's Disease

INTRODUCTION

This study aimed to characterize the morbidity, hospitalization, and mortality rates among patients with adult-onset Still's disease (AOSD) affected by coronavirus disease 2019 (COVID-19) and explore the impact of COVID-19 on the disease activity of AOSD.

METHODS

Data on the clinical and demographic characteristics, COVID-19-related symptoms, and outcomes were retrospectively collected. Patients were stratified according to COVID-19 severity and associations between risk factors and outcomes were analyzed using multivariate logistic regression. The disease activity of patients with AOSD flares after COVID-19 was described.

RESULTS

A total of 188 patients with AOSD were followed up, of whom 75.5% (n = 142) had a confirmed or highly suspected COVID-19. Patients on medium or high-dose oral glucocorticoids or Janus kinase (JAK) inhibitors were at increased risk of developing moderate to severe COVID-19. Six patients suffered flares of AOSD following COVID-19 in a short period; however, the relapse rate was not statistically increased compared with patients without COVID-19.

CONCLUSION

Patients with AOSD receiving medium or high-dose glucocorticoid therapy or JAK inhibitors had worse COVID-19 outcomes. Further work is needed to explore risk factors affecting COVID-19 outcomes and the impact of COVID-19 on disease activity in AOSD.

Improved survival in COVID-19 related sepsis and ARDS treated with a unique "triple therapy" including therapeutic plasma exchange: A single center retrospective analysis

BACKGROUND

Throughout the COVID-19 pandemic, the mortality of critically ill patients remained high. Our group developed a treatment regimen targeting sepsis and ARDS which we labeled "triple therapy" consisting of (1) corticosteroids, (2) therapeutic plasma exchange (TPE), and (3) timely intubation with lung protective ventilation. Our propensity analysis assesses the impact of triple therapy on survival in COVID-19 patients with sepsis and ARDS.

METHODS

Retrospective propensity analysis comparing triple therapy to no triple therapy in adult critically ill COVID-19 patients admitted to the Intensive Care Unit at Lexington Medical Center from 1 March 2020 through 31 October 2021.

RESULTS

Eight hundred and fifty-one patients were admitted with COVID-19 and 53 clinical and laboratory variables were analyzed. Multivariable analysis revealed that triple therapy was associated with increased survival (OR: 1.91; P = .008). Two propensity score-adjusted models demonstrated an increased likelihood of survival in patients receiving triple therapy. Patients with thrombocytopenia were among those most likely to experience increased survival if they received early triple therapy. Decreased survival was observed with endotracheal intubation ≥7 days from hospital admission (P < .001) and there was a trend toward decreased survival if TPE was initiated ≥6 days from hospital admission (P = .091).

CONCLUSION

Our analysis shows that early triple therapy, defined as high-dose methylprednisolone, TPE, and timely invasive mechanical ventilation within the first 96 hours of admission, may improve survival in critically ill septic patients with ARDS secondary to COVID-19 infection. Further studies are needed to define specific phenotypes and characteristics that will identify those patients most likely to benefit.