The immune response to SARS-CoV-2 and COVID-19 immunopathology - Current perspectives

Determinants of post-acute COVID-19 syndrome among hospitalized severe COVID-19 patients: A 2-year follow-up study

BACKGROUND

Post-acute COVID-19 syndrome is a condition where individuals experience persistent symptoms after the acute phase of the COVID-19 infection has resolved, which lowers their quality of life and ability to return to work. This study assessed the prevalence and associated risk factors of post-acute COVID-19 syndrome (PACS) among severe COVID-19 patients who were discharged from Millennium COVID-19 Care Center, Addis Ababa, Ethiopia.

METHODS

A cross-sectional study using data collected from patient charts and a follow-up telephone interview after two years of discharge. Systematic random sampling was used to select a total of 400 patients. A structured questionnaire developed from the case report form for PACS of the World Health Organization (WHO) was used. Frequency and cross-tabulation were used for descriptive statistics. Predictor variables with a p-value <0.25 in bivariate analyses were included in the logistic regression.

RESULT

Out of the 400 patients, 20 patients were dead, 14 patients refused to give consent, and 26 patients couldn't be reached because their phones weren't working. Finally, 340 were included in the study. The majority (68.5%) were males and the mean age was 53.9 (±13.3 SD) years. More than a third (38.1%) of the patients reported the persistence of at least one symptom after hospital discharge. The most common symptoms were fatigue (27.5%) and Cough (15.3%). Older age (AOR 1.04, 95% CI 1.02-1.07), female sex (AOR 1.82, 95% CI 1.00-3.29), presence of comorbidity (AOR 2.38, 95% CI 1.35-4.19), alcohol use (AOR 3.05, 95% CI 1.49-6.26), fatigue at presentation (AOR 2.18, 95% CI 1.21-3.95), and longer hospital stay (AOR 1.06, 95% CI 1.02-1.10) were found to increase the odds of developing post-acute COVID-19 syndrome. Higher hemoglobin level was found to decrease the risk of subsequent post-acute COVID-19 syndrome (AOR 0.84, 95% CI 0.71-0.99).

CONCLUSION

The prevalence of post-acute COVID-19 syndrome is high, with a wide range of persistent symptoms experienced by patients. COVID-19 survivors with the identified risk factors are more susceptible to post-acute COVID-19 and require targeted monitoring and care in a multidisciplinary approach.

Venous thromboembolism and severe COVID-19: a Mendelian randomization trial and transcriptomic analysis

Introduction

Venous thromboembolism (VTE) is known to be intricately linked to severe COVID-19 (sCOVID-19) occurrence. Herein, we employed univariable Mendelian randomization (MR) and transcriptome analysis to predict the causal association and associated signaling networks between VTE and sCOVID-19.

Methods

Potential VTE and sCOVID-19 association was assessed using MR-Egger, weighted median, simple mode, weighted mode, and inverse variance weighted (IVW) regression. We conducted independent univariable analyses involving VTE and sCOVID-19. Using heterogeneity, pleiotropy, and the Leave-One-Out examinations, we performed sensitivity analyses. Thereafter, we performed transcriptome analysis of the GSE164805 dataset to identify differentially expressed genes (DEGs) linked to single nucleotide polymorphisms (SNPs). Lastly, we conducted immune analyses.

Results

Based on our univariable analysis, VTE was a strong indicator of sCOVID-19 development, and it was intricately linked to sCOVID-19. We further conducted sensitivity analysis to demonstrate the reliability of our results. Using differential analysis, we identified 15 major genes, namely, ACSS2, CEP250, CYP4V2, DDB2, EIF6, GBGT1, GSS, MADD, MAPK8IP1, MMP24, YBPC3, NT5DC3, PROCR, SURF6, and YIPF2, which were strongly connected to suppressive adaptive immune as well as augmented inflammatory cells. In addition, we uncovered strong associations with most differential immunologic gene sets, such as, the Major Histocompatibility Complex (MHC), immunoactivators, and immunosuppressors.

Conclusion

Herein, we demonstrated we strong association between VTE and enhanced sCOVID-19 risk. We also identified 15 DEGs which potentially contribute to the shared immunologic pathogenesis between VTE and sCOVID-19.

The glycosaminoglycan-binding chemokine fragment CXCL9(74-103) reduces inflammation and tissue damage in mouse models of coronavirus infection

Introduction

Pulmonary diseases represent a significant burden to patients and the healthcare system and are one of the leading causes of mortality worldwide. Particularly, the COVID-19 pandemic has had a profound global impact, affecting public health, economies, and daily life. While the peak of the crisis has subsided, the global number of reported COVID-19 cases remains significantly high, according to medical agencies around the world. Furthermore, despite the success of vaccines in reducing the number of deaths caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there remains a gap in the treatment of the disease, especially in addressing uncontrolled inflammation. The massive recruitment of leukocytes to lung tissue and alveoli is a hallmark factor in COVID-19, being essential for effectively responding to the pulmonary insult but also linked to inflammation and lung damage. In this context, mice models are a crucial tool, offering valuable insights into both the pathogenesis of the disease and potential therapeutic approaches.

Methods

Here, we investigated the anti-inflammatory effect of the glycosaminoglycan (GAG)-binding chemokine fragment CXCL9(74-103), a molecule that potentially decreases neutrophil transmigration by competing with chemokines for GAG-binding sites, in two models of pneumonia caused by coronavirus infection.

Results

In a murine model of betacoronavirus MHV-3 infection, the treatment with CXCL9(74-103) decreased the accumulation of total leukocytes, mainly neutrophils, to the alveolar space and improved several parameters of lung dysfunction 3 days after infection. Additionally, this treatment also reduced the lung damage. In the SARS-CoV-2 model in K18-hACE2-mice, CXCL9(74-103) significantly improved the clinical manifestations of the disease, reducing pulmonary damage and decreasing viral titers in the lungs.

Discussion

These findings indicate that CXCL9(74-103) resulted in highly favorable outcomes in controlling pneumonia caused by coronavirus, as it effectively diminishes the clinical consequences of the infections and reduces both local and systemic inflammation.

Alpha-1 adrenergic antagonists and the risk of hospitalization or death in non-hospitalized patients with COVID-19: A population-based study

BACKGROUND

Alpha-1 receptor antagonists may interfere with IL-6 signaling and could therefore be a potential treatment for COVID-19. However, the effectiveness of these drugs in mitigating the risk of clinical deterioration among non-hospitalized patients with COVID-19 is unknown.

OBJECTIVES

The aim of this study is to examine the association between alpha-1 antagonist exposure and the 30-day risk of a hospital encounter or death in nonhospitalized patients with COVID-19.

METHODS

We conducted a population-based cohort study of Ontario residents aged 35 years and older who were eligible for public drug coverage and who had a positive test for SARS-CoV-2 between January 1, 2020, and March 1, 2021. We matched each individual receiving an alpha-1 antagonist at the time of their positive test with two non-exposed individuals using propensity scores. Our outcome was a composite of a hospital admission, emergency department visit, or death, 1 to 30 days following the positive test.

RESULTS

We matched 3289 alpha-1 antagonist exposed patients to 6189 unexposed patients. Overall, there was no difference in the 30-day risk of the primary outcome among patients exposed to alpha-1 antagonists at the time of their diagnosis relative to unexposed individuals (28.8% vs. 28.0%; OR 1.00, 95% CI 0.91 to 1.11). In a secondary analysis, individuals exposed to alpha-1 antagonists had a lower risk of death in the 30 days following a COVID diagnosis (OR 0.79; 95% CI 0.66 to 0.93).

CONCLUSION

Alpha-1 antagonists did not mitigate the 30-day risk of clinical deterioration in non-hospitalized patients with COVID-19. Our findings do not support the general repurposing of alpha-1 antagonists as a treatment for such patients, although there may be subgroups of patients in whom further research is warranted.

Control of complement-induced inflammatory responses to SARS-CoV-2 infection by anti-SARS-CoV-2 antibodies

Dysregulated immune responses contribute to the excessive and uncontrolled inflammation observed in severe COVID-19. However, how immunity to SARS-CoV-2 is induced and regulated remains unclear. Here, we uncover the role of the complement system in the induction of innate and adaptive immunity to SARS-CoV-2. Complement rapidly opsonizes SARS-CoV-2 particles via the lectin pathway. Complement-opsonized SARS-CoV-2 efficiently induces type-I interferon and pro-inflammatory cytokine responses via activation of dendritic cells, which are inhibited by antibodies against the complement receptors (CR) 3 and 4. Serum from COVID-19 patients, or monoclonal antibodies against SARS-CoV-2, attenuate innate and adaptive immunity induced by complement-opsonized SARS-CoV-2. Blocking of CD32, the FcγRII antibody receptor of dendritic cells, restores complement-induced immunity. These results suggest that opsonization of SARS-CoV-2 by complement is involved in the induction of innate and adaptive immunity to SARS-CoV-2 in the acute phase of infection. Subsequent antibody responses limit inflammation and restore immune homeostasis. These findings suggest that dysregulation of the complement system and FcγRII signaling may contribute to severe COVID-19.

COVID-19 and Alzheimer's disease: Impact of lockdown and other restrictive measures during the COVID-19 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection initially results in respiratory distress symptoms but can also lead to central nervous system (CNS) and neurological manifestations, significantly impacting coronavirus disease 2019 (COVID-19) patients with neurodegenerative diseases. Additionally, strict lockdown measures introduced to curtail the spread of COVID-19 have raised concerns over the wellbeing of patients with dementia and/or Alzheimer's disease. The aim of this review was to discuss the overlapping molecular pathologies and the potential bidirectional relationship between COVID-19 and Alzheimer's dementia, as well as the impact of lockdown/restriction measures on the neuropsychiatric symptoms (NPS) of patients with Alzheimer's dementia. Furthermore, we aimed to assess the impact of lockdown measures on the NPS of caregivers, exploring its potential effects on the quality and extent of care they provide to dementia patients.We utilized the PubMed and Google Scholar databases to search for articles on COVID-19, dementia, Alzheimer's disease, lockdown, and caregivers. Our review highlights that patients with Alzheimer's disease face an increased risk of COVID-19 infection and complications. Additionally, these patients are likely to experience greater cognitive decline. It appears that these issues are primarily caused by the SARS-CoV-2 infection and appear to be further exacerbated by restrictive/lockdown measures. Moreover, lockdown measures introduced during the pandemic have negatively impacted both the NPSs of caregivers and their perception of the wellbeing of their Alzheimer's patients. Thus, additional safeguard measures, along with pharmacological and non-pharmacological approaches, are needed to protect the wellbeing of dementia patients and their caregivers in light of this and possible future pandemics.

Determinants of pressure injury development in patients with COVID-19

OBJECTIVE

Pressure injuries (PIs) often develop in critically ill patients due to immobility, and underlying comorbidities that decrease tissue perfusion and wound healing capacity. This study sought to provide epidemiological data on determinants and current managements practices of PI in patients with COVID-19.

METHOD

A US national insurance-based database consisting of patients with coronavirus or COVID-19 diagnoses was used for data collection. Patients were filtered by International Classification of Diseases (ICD) codes corresponding to coronavirus or COVID-19 diagnosis between 2019-2020. Diagnosis of PI following COVID-19 diagnosis was queried. Demographic data and comorbidity information was compared. Logistic regression analysis was used to determine predictors for both PI development and likelihood of operative debridement.

RESULTS

A total of 1,477,851 patients with COVID-19 were identified. Of these, 15,613 (1.06%) subsequently developed a PI, and 8074 (51.7%) of these patients had an intensive care unit (ICU) admission. The average and median time between diagnosis of COVID-19 and PI was 39.4 and 26 days, respectively. PI was more likely to occur in patients with COVID-19 with: diabetes (odds ratio (OR): 1.39, 95% confidence interval (CI): 1.29-1.49; p<0.001); coronary artery disease (OR: 1.11, 95% CI: 1.04-1.18, p=0.002), hypertension (OR: 1.43, 95% CI: 1.26-1.64; p<0.001); chronic kidney disease (OR: 1.18, 95% CI: 1.10-1.26; p<0.001); depression (OR: 1.45, 95% CI 1.36-1.54; p<0.001); and long-term non-steroidal anti-inflammatory drug use (OR: 1.21, 95% CI: 1.05-1.40; p=0.007). They were also more likely in critically ill patients admitted to the ICU (OR: 1.40, 95% CI: 1.31-1.48; p<0.001); and patients requiring vasopressors (OR:1.25, 95% CI: 1.13-1.38; p<0.001), intubation (OR: 1.21, 95% CI 1.07-1.39; p=0.004), or with a diagnosis of sepsis (OR: 2.38, 95% CI 2.22-2.55; p<0.001). ICU admission, sepsis, buttock and lower back PI along with increasing Charlson Comorbidity Index (CCI) (OR: 1.04, 95% CI 1.00-1.08; p=0.043) was associated with surgical debridement. The vast majority of patients with COVID-19 did not undergo operative debridement or wound coverage.

CONCLUSION

PIs are widely prevalent in patients with COVID-19, especially in those who are critically ill, yet the vast majority do not undergo operative procedures.

DECLARATION OF INTEREST

The authors have no conflicts of interest to declare.

The characteristics of BCR-CDR3 repertoire in COVID-19 patients and SARS-CoV-2 vaccinated volunteers

The global COVID-19 pandemic has caused more than 1 billion infections, and numerous SARS-CoV-2 vaccines developed rapidly have been administered over 10 billion doses. The world is continuously concerned about the cytokine storms induced by the interaction between SARS-CoV-2 and host, long COVID, breakthrough infections postvaccination, and the impact of SARS-CoV-2 variants. BCR-CDR3 repertoire serves as a molecular target for monitoring the antiviral response "trace" of B cells, evaluating the effects, mechanisms, and memory abilities of individual responses to B cells, and has been successfully applied in analyzing the infection mechanisms, vaccine improvement, and neutralizing antibodies preparation of influenza virus, HIV, MERS, and Ebola virus. Based on research on BCR-CDR3 repertoire of COVID-19 patients and volunteers who received different SARS-CoV-2 vaccines in multiple laboratories worldwide, we focus on analyzing the characteristics and changes of BCR-CDR3 repertoire, such as diversity, clonality, V&J genes usage and pairing, SHM, CSR, shared CDR3 clones, as well as the summary on BCR sequences targeting virus-specific epitopes in the preparation and application research of SARS-CoV-2 potential therapeutic monoclonal antibodies. This review provides comparative data and new research schemes for studying the possible mechanisms of differences in B cell response between SARS-CoV-2 infection or vaccination, and supplies a foundation for improving vaccines after SARS-CoV-2 mutations and potential antibody therapy for infected individuals.

Complications Rates Among Revision Total Knee Arthroplasty Patients Diagnosed With COVID-19 Postoperatively

BACKGROUND

The COVID-19 pandemic introduced a new set of challenges for the arthroplasty community, including the management of patients diagnosed with COVID-19 following revision total knee arthroplasty (rTKA) and its potential impact on postoperative recovery. This study sought to characterize the risks of postoperative COVID-19 infection among rTKA patients.

METHODS

A large national database was utilized to query 8,022 total patients who underwent rTKA between 2018 and 2021, of which 60 had a COVID diagnosis within 90 days after surgery (rTKA/COVID positive). These patients were 1:10 propensity-score matched to 600 rTKA patients who did not have a 90-day postoperative COVID diagnosis (rTKA/COVID negative) and 600 COVID positive patients who did not undergo rTKA. Controlling for potential confounders, multivariate logistic regressions were utilized to compare 90-day postoperative complications between groups.

RESULTS

Compared to rTKA/COVID negativepatients, the rTKA/COVID positive cohort had significantly higher rates of pneumonia (odds ratio [OR] = 6.1, P < .001), pulmonary embolism (PE) (OR = 32.4, P < .001), deep venous thrombosis (DVT) (OR = 32.4, P < .001), and 90-day readmissions (OR = 2.1, P = .02). Similarly, the rTKA/COVID positive cohort had significantly higher rates of pneumonia (OR = 4.3, P = .001), PE (OR = 36.8, P < .001), and DVT (OR = 36.8, P < .001) compared to COVID positive patients who did not undergo rTKA.

CONCLUSIONS

Revision total knee arthroplasty patients diagnosed with COVID-19 postoperatively had increased rates of thromboembolic events, pneumoniae, and 90-day readmissions. Risk mitigation efforts would suggest extending the prophylactic anticoagulation period for rTKA patients diagnosed with postoperative COVID-19.

Identification of the shared molecular mechanisms between major depressive disorder and COVID-19 from postmortem brain transcriptome analysis

OBJECTIVES

This study aims to investigate the molecular mechanisms underlying the interaction of major depressive disorder (MDD) and COVID-19, and on this basis, diagnostic biomarkers and potential therapeutic drugs are further explored.

METHODS

Differential gene expression analysis and weighted gene co-expression network analysis (WGCNA) were employed to identify common key genes involved in the pathogenesis of COVID-19 and MDD. Correlations with clinical features were explored. Detailed mechanisms were further investigated through protein interaction networks, GSEA, and immune cell infiltration analysis. Finally, Enrichr's Drug Signature Database and Coremine Medical were used to predict the potential drugs associated with key genes.

RESULTS

The study identified 18 genes involved in both COVID-19 and MDD. Four key genes (MBP, CYP4B1, ERMN, and SLC26A7) were selected based on clinical relevance. A multi-gene prediction model showed good diagnostic efficiency for the two diseases: AUC of 0.852 for COVID-19 and 0.915 for MDD. GO and GSEA analyses identified specific biological functions and pathways associated with key genes in COVID-19 (axon guidance, metabolism, stress response) and MDD (neuron ensheathment, biosynthesis, glutamatergic neuron differentiation). The key genes also affected immune infiltration. Potential therapeutic drugs, including small molecules and traditional Chinese medicines, targeting these genes were identified.

CONCLUSION

This study provides insights into the complex biological mechanisms underlying COVID-19 and MDD, develops an effective diagnostic model, and predicts potential therapeutic drugs, which may contribute to the prevention and treatment of these two prevalent diseases.

ACE I/D polymorphism is a risk factor for the clinical severity of COVID-19 in Brazilian male patients

BACKGROUND

The renin-angiotensin system is potentially involved in the pathogen-host interaction in the disease caused by SARS-CoV-2, since the angiotensin-converting enzyme (ACE) 2 serves as a receptor for the virus. The impact of the pandemic in specific regions and ethnic groups highlights the importance of investigating genetic factors that disrupt the balance of the system in response to SARS-CoV-2 infection, especially in genes with ethnic frequency variations. Therefore, this study aimed to evaluate the influence of the ACE I/D polymorphism on the incidence and severity of COVID-19 in a sample of the Brazilian population.

METHODS AND RESULTS

70 severe cases and 355 mild cases patients were evaluated. DNA extraction was performed using a QIAamp DNA Blood Mini kit. Genotyping of ACE I/D polymorphism was performed. Clinical outcomes were obtained from the patients' records. We found an association between the ACE I/D polymorphism and the incidence or severity of COVID-19 in male participants. Moreover, we observed a relationship between severity and increasing age and body weight and a higher frequency of II genotype individuals among those who had a cough as their symptoms in mild patients. No differences were observed in leukocyte count or other parameters related to the inflammatory response in severe patients.

CONCLUSIONS

Our data showed the influence of the ACE I/D polymorphism on severity of COVID-19 in males, as well as on the occurrence of cough in patients with mild symptoms, with a higher incidence in those carrying the I allele.

The immune inflammation factors associated with disease severity and poor prognosis in patients with COVID-19: A retrospective cohort study

Coronavirus disease 2019 (COVID-19) is associated with immune dysregulation and cytokine storm. It is essential to explore the immune response characteristics of peripheral circulation in COVID-19 patients to reveal pathogenesis and predict disease progression. In this study, the levels of total immunoglobulins (IgG, IgM, IgA), complement (C3, C4)，lymphocyte subsets (CD3+ cell，CD4+ cell，CD8+ cell, NK cell, CD19+ cell and CD45+ cell) and cytokines (IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17, IL-12p, IL-1β, TNF-α, IFN-α and IFN-γ) were retrospectively analyzed in COVID-19 patients. A total of 513 patients were enrolled in this study, cases were distributed according to clinical status as mild or moderate (n = 212), severe survivors (n = 197) and severe non-survivors (n = 104). IL-6, IL-8, IL-10 and IFN-γ were increased in severe patients compared with non-severe patients, despite decreased CD45+ cell, CD3+ cell, CD4+ cell, CD8+ cell, CD19+ cell, and NK cell. Compared with severe survivors, the levels of L-6, IL-8 and IL-10 in non-survivors increased significantly, and levels of C3, CD45+ cell, CD3+ cell，CD4+ cell，CD8+ cell, and NK cell decreased. Moreover, age, IL-8, IL-10, CD8+cells and NK cell were independent risk factors for the severity of COVID-19. Multivariable regression showed increasing odds ratio of in-hospital death associated with tumor, older age, higher IL-8 level, and decreasing odds ratio of in-hospital death associated with increased levels of CD8+cell and NK cell. Finally, patients with tumor, or high IL-6 or high IL-10 expression and lower CD8+ or lower NK levels exhibited a significantly shorter survival time. In conclusion, our study provides findings of the immunological characteristics associated with disease severity to predict the progression of COVID-19. The immune inflammation factors, such as IL-6, IL-8, IL-10, CD8+ cell and NK cell, could serve as excellent biomarkers for monitoring or predicting COVID-19 progression therapeutic to COVID-19 patients.

Performance Analysis of Serodiagnostic Tests to Characterize the Incline and Decline of the Individual Humoral Immune Response in COVID-19 Patients: Impact on Diagnostic Management

Serodiagnostic tests for antibody detection to estimate the immunoprotective status regarding SARS-CoV-2 support diagnostic management. This study aimed to investigate the performance of serological assays for COVID-19 and elaborate on test-specific characteristics. Sequential samples (n = 636) of four panels (acute COVID-19, convalescent COVID-19 (partly vaccinated post-infection), pre-pandemic, and cross-reactive) were tested for IgG by indirect immunofluorescence test (IIFT) and EUROIMMUN EUROLINE Anti-SARS-CoV-2 Profile (IgG). Neutralizing antibodies were determined by a virus neutralization test (VNT) and two surrogate neutralization tests (sVNT, GenScript cPass, and EUROIMMUN SARS-CoV-2 NeutraLISA). Analysis of the acute and convalescent panels revealed high positive (78.3% and 91.6%) and negative (91.6%) agreement between IIFT and Profile IgG. The sVNTs revealed differences in their positive (cPass: 89.4% and 97.0%, NeutraLISA: 71.5% and 72.1%) and negative agreement with VNT (cPass: 92.3% and 50.0%, NeutraLISA: 95.1% and 92.5%) at a diagnostic specificity of 100% for all tests. The cPass showed higher inhibition rates than NeutraLISA at VNT titers below 1:640. Cross-reactivities were only found by cPass (57.1%). Serodiagnostic tests, which showed substantial agreement and fast runtime, could provide alternatives for cell-based assays. The findings of this study suggest that careful interpretation of serodiagnostic results obtained at different times after SARS-CoV-2 antigen exposure is crucial to support decision-making in diagnostic management.

Mesenchymal Stem Cells Therapy for COVID-19: From Basic Research to Clinical Trial

The novel pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), a serious challenge for human health. In severe cases, patients suffer from acute respiratory distress syndrome even organ failure, usually owing to the dysregulated immune response and widespread inflammation. Considering that there is no known cure for COVID-19 despite the increased morbidity and mortality rate of COVID-19, modalities targeting immunity and inflammation may be promising therapeutics against COVID-19. Mesenchymal stem cells (MSCs) possessing immunomodulatory, anti-inflammatory, anti-apoptotic, and antiviral properties, can be of potential benefit to a subset of severe and critically ill patients with COVID-19. In the present study, we described the underlying mechanisms of MSCs therapy and provided a thorough research study on the recent clinical trials of MSCs for SARS-CoV-2 infection.

SARS-CoV-2 decreases malaria severity in co-infected rodent models

Coronavirus disease 2019 (COVID-19) and malaria, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Plasmodium parasites, respectively, share geographical distribution in regions where the latter disease is endemic, leading to the emergence of co-infections between the two pathogens. Thus far, epidemiologic studies and case reports have yielded insufficient data on the reciprocal impact of the two pathogens on either infection and related diseases. We established novel co-infection models to address this issue experimentally, employing either human angiotensin-converting enzyme 2 (hACE2)-expressing or wild-type mice, in combination with human- or mouse-infective variants of SARS-CoV-2, and the P. berghei rodent malaria parasite. We now show that a primary infection by a viral variant that causes a severe disease phenotype partially impairs a subsequent liver infection by the malaria parasite. Additionally, exposure to an attenuated viral variant modulates subsequent immune responses and provides protection from severe malaria-associated outcomes when a blood stage P. berghei infection was established. Our findings unveil a hitherto unknown host-mediated virus-parasite interaction that could have relevant implications for disease management and control in malaria-endemic regions. This work may contribute to the development of other models of concomitant infection between Plasmodium and respiratory viruses, expediting further research on co-infections that lead to complex disease presentations.

Evaluation of the Panbio™ COVID-19 IgG rapid test device performance

Background

The Panbio™ COVID-19 IgG Rapid Test Device ("Panbio™") detects IgG antibodies against the SARS-CoV-2 spike protein from viral infection or vaccination.

Objectives

To determine the diagnostic sensitivity and specificity of the Panbio™ professional use test, using fingerstick whole blood and venous plasma.

Study design

Fingerstick whole blood and venous plasma from each participant were tested with Panbio™ and compared against the SARS-CoV-2 IgG II assay on the Abbott Architect™ platform (Europe) or the equivalent AdviseDx SARS-CoV-2 IgG II Abbott Alinity i™ platform (US). 447 evaluable participants were enrolled across 6 US and 9 European clinical centers.

Results

For unvaccinated participants with PCR-confirmed infection ≥21 days post-symptom onset, the Panbio™ sensitivity with fingerstick whole blood was 92.6 % (95 % CI: 85.9, 96.7), and the specificity was 97.0 % (95 % CI: 93.1, 99.0). For venous plasma, the sensitivity was 90.0 % (95 % CI: 79.5, 96.2) for participants with PCR-confirmed infection and symptom onset 22-180 days ago; the specificity was 96.3 % (92.2, 98.6). For vaccinated participants, the sensitivity was 98.4 % (95 % CI: 91.2, 100.0) for fingerstick whole blood and 96.7 % (95 % CI: 88.7, 99.6) for venous plasma.

Conclusion

The Panbio™ test had high sensitivity and specificity for detecting IgG against the SARS-CoV-2 spike protein.

Prognostic significance of serum miR-18a-5p in severe COVID-19 Egyptian patients

BACKGROUND

The identification of miRNAs as well as characterization of miRNA-mRNA interactions in SARS-CoV-2 infection is important to understand their role in disease pathogenesis. Therefore the aim of the present study was to measure the expression levels of hsa-mir-18a-5p in the sera of severe COVID-19 Egyptian patients admitted to ICU to investigate its roles in the pathogenesis and severity of COVID-19 disease.

METHODS

A total of 180 unvaccinated severe COVID-19 patients were enrolled in our study. Besides the routine laboratory work, the expression level of hsa-mir-18a-5p was done using reverse transcription quantitative real-time PCR (RTqPCR) technique. Also, target genes of hsa-mir-18a-5p were explored by using online bioinformatics databases.

RESULTS

The expression level of hsa-mir-18a-5p decreased in nonsurvival severe COVID-19 patients (0.38 ± 0.26) when compared to the survival ones (0.84 ± 0.23). While as a prognostic tool for the prediction of bad prognosis and mortality among severe COVID-19 patients, our results showed that the serum hsa-mir-18a-5p expression level is a good sensitive and specific marker. By using bioinformatics tools, our results revealed that the decreased hsa-mir-18a-5p expression level may have a crucial role in COVID-19 pathogenesis and severity through decreased immunological responses (interpreted as lymphopenia) or increased inflammation (interpreted as increased serum levels of IL-6, CRP, LDH).

CONCLUSION

Taken together, the decreased expression level of hsa-mir-18a-5p could be a bad prognostic marker and therapeutic overexpression of hsa-mir-18a-5p could be a novel approach in the treatment of COVID-19 disease.

Post-COVID-19 depression and serum interleukin 6 levels: A systematic review and meta-analysis of COVID-19 convalescents with and without depression

OBJECTIVES

Depression is among the psychiatric sequelae of COVID-19, affecting more than 20% of the convalescents. Its underlying pathophysiology remains unclear. Interleukin 6 (IL-6), a pro-inflammatory cytokine, plays a critical role in the COVID-19-associated cytokine storm, has been implicated in depressive disorders, and may thus be involved in post-COVID-19 depression.

METHODS

PubMed, Scopus, Embase, and Web of Science were systematically searched for relevant studies assessing peripheral IL-6 levels in convalescents who developed depression after COVID-19 vs. convalescents who did not.

RESULTS

Five studies were included in our systematic review, and four entered the meta-analysis. The meta-analysis revealed that post-COVID people with de novo depression did not have statistically significant differences in IL-6 levels compared to those without depression (standardised mean difference (SMD) = 0.09, 95% confidence interval (CI) = -0.35, 0.54, p-value = 0.68).

CONCLUSIONS

Although convalescents with depression did not have significantly higher IL-6 levels than convalescents without depression, the results should be interpreted considering the limited sample size and the low power of the included studies.

Recombinant C1 inhibitor in the prevention of severe COVID-19: a randomized, open-label, multi-center phase IIa trial

Background

Conestat alfa (ConA), a recombinant human C1 inhibitor, may prevent thromboinflammation.

Methods

We conducted a randomized, open-label, multi-national clinical trial in which hospitalized adults at risk for progression to severe COVID-19 were assigned in a 2:1 ratio to receive either 3 days of ConA plus standard of care (SOC) or SOC alone. Primary and secondary endpoints were day 7 disease severity on the WHO Ordinal Scale, time to clinical improvement within 14 days, and safety, respectively.

Results

The trial was prematurely terminated because of futility after randomization of 84 patients, 56 in the ConA and 28 in the control arm. At baseline, higher WHO Ordinal Scale scores were more frequently observed in the ConA than in the control arm. On day 7, no relevant differences in the primary outcome were noted between the two arms (p = 0.11). The median time to defervescence was 3 days, and the median time to clinical improvement was 7 days in both arms (p = 0.22 and 0.56, respectively). Activation of plasma cascades and endothelial cells over time was similar in both groups. The incidence of adverse events (AEs) was higher in the intervention arm (any AE, 30% with ConA vs. 19% with SOC alone; serious AE, 27% vs. 15%; death, 11% vs. 0%). None of these were judged as being related to the study drug.

Conclusion

The study results do not support the use of ConA to prevent COVID-19 progression.

Clinical trial registration

https://clinicaltrials.gov, identifier NCT04414631.

SARS-CoV-2 Impact on Red Blood Cell Morphology

Severe COVID-19 alters the biochemical and morphological characteristics of blood cells in a wide variety of ways. To date, however, the vast majority of research has been devoted to the study of leukocytes, while erythrocyte morphological changes have received significantly less attention. The aim of this research was to identify erythrocyte morphology abnormalities that occur in COVID-19, compare the number of different poikilocyte types, and measure erythrocyte sizes to provide data on size dispersion. Red blood cells obtained from 6 control donors (800-2200 cells per donor) and 5 COVID-19 patients (800-1900 cells per patient) were examined using low-voltage scanning electron microscopy. We did not discover any forms of erythrocyte morphology abnormalities that would be specific to COVID-19. Among COVID-19 patients, we observed an increase in the number of acanthocytes (p = 0.01) and a decrease in the number of spherocytes (p = 0.03). In addition, our research demonstrates that COVID-19 causes an increase in the median (p = 0.004) and interquartile range (p = 0.009) when assessing erythrocyte size. The limitation of our study is a small number of participants.

The S1'-S3' Pocket of the SARS-CoV-2 Main Protease Is Critical for Substrate Selectivity and Can Be Targeted with Covalent Inhibitors

The main protease (Mpro ) of SARS-CoV-2 is a well-characterized target for antiviral drug discovery. To date, most antiviral drug discovery efforts have focused on the S4-S1' pocket of Mpro ; however, it is still unclear whether the S1'-S3' pocket per se can serve as a new site for drug discovery. In this study, the S1'-S3' pocket of Mpro was found to differentially recognize viral peptidyl substrates. For instance, S3' in Mpro strongly favors Phe or Trp, and S1' favors Ala. The peptidyl inhibitor D-4-77, which possesses an α-bromoacetamide warhead, was discovered to be a promising inhibitor of Mpro , with an IC50 of 0.95 μM and an antiviral EC50 of 0.49 μM. The Mpro /inhibitor co-crystal structure confirmed the binding mode of the inhibitor to the S1'-S3' pocket and revealed a covalent mechanism. In addition, D-4-77 functions as an immune protectant and suppresses SARS-CoV-2 Mpro -induced antagonism of the host NF-κB innate immune response. These findings indicate that the S1'-S3' pocket of SARS-CoV-2 Mpro is druggable, and that inhibiting SARS-CoV-2 Mpro can simultaneously protect human innate immunity and inhibit virion assembly.

Peptide delivery of a multivalent mRNA SARS-CoV-2 vaccine

Lipid nanoparticles (LNP) have been instrumental in the success of mRNA vaccines and have opened up the field to a new wave of therapeutics. However, what is ahead beyond the LNP? The approach herein used a nanoparticle containing a blend of Spike, Membrane and Envelope antigens complexed for the first time with the RALA peptide (RALA-SME). The physicochemical characteristics and functionality of RALA-SME were assessed. With >99% encapsulation, RALA-SME was administered via intradermal injection in vivo, and all three antigen-specific IgG antibodies were highly significant. The IgG2a:IgG1 ratio were all >1.2, indicating a robust TH1 response, and this was further confirmed with the T-Cell response in mice. A complete safety panel of markers from mice were all within normal range, supported by safety data in hamsters. Vaccination of Syrian Golden hamsters with RALA-SME derivatives produced functional antibodies capable of neutralising SARS-CoV-2 from both Wuhan-Hu-1 and Omicron BA.1 lineages after two doses. Antibody levels increased over the study period and provided protection from disease-specific weight loss, with inhibition of viral migration down the respiratory tract. This peptide technology enables the flexibility to interchange and add antigens as required, which is essential for the next generation of adaptable mRNA vaccines.

Streptococcus uberis induced expressions of pro-inflammatory IL-6, TNF-α, and IFN-γ in bovine mammary epithelial cells associated with inhibited autophagy and autophagy flux formation

Autophagy is a highly conserved cellular defensive mechanism that can eliminate bacterial pathogens such as Streptococcus uberis, that causes mastitis in cows. However, S. uberis induced autophagy is still unclear. In this study, we tested if certain inflammatory cytokines such as IL-6, TNF-α, and IFN-γ, critical in mastitis due to S. uberis infection, regulate autophagy activation in bovine mammary epithelial cells (bMECs). Using Western blot and laser scanning confocal microscope in bMECs challenged by S. uberis, showed that the expression of IL-6, TNF-α, IFN-γ oscillated with the expressions of autophagic Atg5, ULK1, PTEN, P62, and LC3ӀӀ/LC3Ӏ. S. uberis infection induced autophagosomes and LC3 puncta in bMECs with upregulation of Atg5, ULK1, PTEN, LC3ӀӀ/LC3Ӏ, and downregulation of P62. The levels of IL-6, TNF-α, and IFN-γ increased during autophagy flux formation to decrease during autophagy induction. Autophagy inhibition increased the expression of IL-6, TNF-α, and IFN-γ and increased S. uberis burden. This study indicates autophagy is induced during S. uberis infection and IL-6, TNF-α, and IFN-γ contribute to autophagy and autophagy flux formation.

Elevated Levels of Cytotoxicity, Cytokines, and Anti-SARS-CoV-2 Antibodies in Mild Cases of COVID-19

Current evidence shows higher production of cytokines and antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) in severe and critical cases of Coronavirus Disease 2019 (COVID-19) in comparison with patients with moderate or mild disease. A recent hypothesis proposes an important role of genotoxicity and cytotoxicity in the induction of the cytokine storm observed in some patients at later stages of the disease. Interestingly, in this study, we report significantly higher levels of interleukin (IL)-1β, IL-6, MCP-1, and IL-4 cytokines in mild COVID-19 patients versus severe cases, as well as a high frequency of karyorrhexis (median [Me] = 364 vs. 20 cells) and karyolysis (Me = 266 vs. 52 cells) in the mucosal epithelial cells of both groups of patients compared with uninfected individuals. Although we observed higher levels of anti-SARS-CoV-2 IgM and IgG antibodies in COVID-19 patients, IgM antibodies were significantly higher only in mild cases, for the N and the S viral antigens. High levels of IgG antibodies were observed in both mild and severe cases. Our results showed elevated concentrations of proinflammatory and anti-inflammatory cytokines in mild cases, which may reflect an active innate immune response and could be related to the higher IgM and IgG antibody levels found in those patients. In addition, we found that SARS-CoV-2 infection induces cytotoxic damage in the oral mucosa, highlighting the importance of studying the genotoxic and cytotoxic events induced by infection and its role in the pathophysiology of COVID-19.

Effect of vitamin D receptor gene BsmI polymorphism on hospitalization of SARS-CoV-2 positive patients

Low vitamin D levels and adverse effects have been reported in SARS-COV-2 positive patients. This study examined the effect of the vitamin D receptor gene BsmI polymorphism on SARS-COV-2 positive patients. A total of 80 SARS-COV-2 positive inpatients were included in the study, and 110 healthy individuals were included as a control group. The 25-(OH) vitamin D3, lymphocyte, and activated partial thromboplastin time levels of SARS-COV-2 positive patients were lower than those of the control group. The prothrombin time (PT), international normalized ratio (INR), D-dimer, C-reactive protein (CRP), procalcitonin, and ferritin levels of SARS-COV-2 positive patients were higher than those of the control group. A negative correlation was found between 25-(OH) vitamin D3 levels and white blood cell count, PT, INR, D-dimer, CRP, procalcitonin, and ferritin levels in SARS-COV-2 positive patients. The 25-(OH) vitamin D3 level in individuals with the BB genotype was higher than the 25-(OH) vitamin D3 level in individuals with the Bb and bb genotype. A statistically significant difference was found between the groups in terms of the genotype and allele distributions of BsmI polymorphism. When the genotypes were analyzed in terms of bb versus Bb + BB, a statistically significant difference was found between the groups. However, this finding was not found between the intensive care inpatient subgroup and the other inpatient subgroup. In conclusion, BsmI b allele and bb genotype were associated with hospitalization for SARS-COV-2 infection. This may be because individuals with b allele have low levels of vitamin D.

Acquired Hemophilia A after SARS-CoV-2 Infection: A Case Report and an Updated Systematic Review

The role of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been implicated in the pathogenesis of acquired hemophilia A (AHA). The aim of this study is to report our case and to summarize clinical studies on de novo AHA after SARS-CoV-2 infection. We performed a systematic search on the association of SARS-CoV-2 with AHA in four medical databases up to 28 May 2023. Eligible studies should include de novo AHA patients who had SARS-CoV-2 infection before or concomitant with the diagnosis of AHA. Findings were synthesized narratively. In addition, we report the case of a 62-year-old female patient, who presented to our clinic with left flank pain 2 weeks after SARS-CoV-2 infection. Clinical investigations confirmed AHA and imaging studies revealed retroperitoneal bleeding. Her hemostasis was successfully secured with bypassing agents; however, despite immunosuppressive therapy, high inhibitor titer persisted. In the systematic review, we identified only 12 relevant cases with a questionable cause-effect relationship between SARS-CoV-2 infection and AHA. Based on the qualitative analysis of the relevant publications, current clinical evidence is insufficient to support a cause-effect relationship. The analysis of data from ongoing AHA registries can serve further evidence.

Macrophage-Derived Chemokine MDC/CCL22: An Ambiguous Finding in COVID-19

Macrophage-derived chemokine (MDC/CCL22) is a chemokine of the C-C subfamily. It is involved in T-cellular maturation and migration. Our previous research shows that plasma CCL22/MDC tends to show a statistically significant depletion of concentrations in acute patients and convalescents when compared to healthy donors. In the current work, we investigate existing views on MDC/CCL22 dynamics in association with various pathologies, including respiratory diseases and, specifically, COVID-19. Additionally, we present our explanations for the observed decrease in MDC/CCL22 concentrations in COVID-19. The first hypothesis we provide implies that viral products bind to MDC/CCL22 and block its activity. Another explanation for this phenomenon is based on dendritic cells population and the inhibition of their function.

Initial immune response after exposure to Mycobacterium tuberculosis or to SARS-COV-2: similarities and differences

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) and Coronavirus disease-2019 (COVID-19), whose etiologic agent is severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), are currently the two deadliest infectious diseases in humans, which together have caused about more than 11 million deaths worldwide in the past 3 years. TB and COVID-19 share several aspects including the droplet- and aerosol-borne transmissibility, the lungs as primary target, some symptoms, and diagnostic tools. However, these two infectious diseases differ in other aspects as their incubation period, immune cells involved, persistence and the immunopathological response. In this review, we highlight the similarities and differences between TB and COVID-19 focusing on the innate and adaptive immune response induced after the exposure to Mtb and SARS-CoV-2 and the pathological pathways linking the two infections. Moreover, we provide a brief overview of the immune response in case of TB-COVID-19 co-infection highlighting the similarities and differences of each individual infection. A comprehensive understanding of the immune response involved in TB and COVID-19 is of utmost importance for the design of effective therapeutic strategies and vaccines for both diseases.

Safety, Tolerability, Bioavailability, and Biological Activity of Inhaled Interferon-α2b in Healthy Adults: The IN2COVID Phase I Randomized Trial

BACKGROUND AND OBJECTIVES

Interferons have been identified as a potential treatment alternative for coronavirus disease 2019. This study assessed the safety, tolerability, bioavailability, and biological activity of inhaled interferon-α2b (IFN)-α2b in healthy adults.

METHODS

A double-blind, randomized, phase I clinical trial was conducted with two cohorts of healthy subjects aged 18-50 years. The first cohort received 2.5 MIU of inhaled IFN-α2b twice daily for 10 days (n = 6) or placebo (n = 3); the second cohort received 5.0 MIU of inhaled IFN-α2b in a similar scheme (n = 6) or placebo (n = 3). The first two doses were administered in an emergency department, then participants completed their treatment at home. Safety was measured through vital signs, new symptoms, and laboratory tests. Tolerability was measured as participants' treatment acceptability. Bioavailability and biological activity were measured from serum IFNα concentrations and real-time quantitative polymerase chain reaction of interferon-induced genes in blood before and after treatments.

RESULTS

Exposure to inhaled IFN-α2b at 2.5-MIU or 5-MIU doses did not produce statistically significant changes in participant vital signs, or elicit new symptoms, and standard hematological and biochemical blood measurements were comparable to those recorded in individuals who received placebo. A total of 58 adverse events were observed. All were mild or moderate and did not require medical care. All participants reported very high tolerability towards a twice-daily nebulized treatment for 10 days (98.0, 97.0, and 97.0 in the placebo, 2.5-MIU, and 5-MIU groups, respectively, on a 0- to 100-mm visual analog scale). A dose-dependent mild increase in serum IFN-α concentrations and an increase in serum RNA expression of IFN-induced genes were observed 11 days after treatment (p < 0.05 for all between-group comparisons).

CONCLUSIONS

Inhaled IFN-α2b was preliminarily safe and well tolerated, and induced systemic biological activity in healthy subjects.

CLINICAL TRIAL REGISTRATION

The trial was registered in ClinicalTrials.gov (NCT04988217), 3 August, 2021.

Serum profiles of pro-inflammatory and anti-inflammatory cytokines in non-hospitalized patients with mild/moderate COVID-19 infection

This study attempted to explore pro-inflammatory and anti-inflammatory responses in patients with mild/moderate coronavirus disease 19 (COVID-19). Eight pro-inflammatory (IL-1α, IL-1β, IL-12, IL-17A, IL-17E, IL-31, IFN-γ and TNF-α) and three anti-inflammatory (IL-1Ra, IL-10 and IL-13) cytokines, as well as two chemokines (CXCL9 and CXCL10), were analyzed in the serum from ninety COVID-19 patients and healthy controls. Cytokine/chemokine levels were measured using enzyme-linked immunosorbent assay kits. Results revealed that IL-1α, IL-1β, IL-10, IL-12, IL-13, IL-17A, IL-31, IFN-γ, TNF-α and CXCL10 were significantly higher in patients than in controls, while IL-1Ra levels were significantly lower in patients. IL-17E and CXCL9 levels showed no significant differences between patients and controls. Seven cytokines/chemokines recorded an area under the curve greater than 0.8: IL-12 (0.945), IL-17A (0.926), CXCL10 (0.909), IFN-γ (0.904), IL-1α (0.869), TNF-α (0.825) and IL-10 (0.821). As indicated by the odds ratio, elevated levels of nine cytokines/chemokines were associated with an increased risk of COVID-19: IL-1α (19.04), IL-10 (5.01), IL-12 (43.66), IL-13 (4.25), IL-17A (16.62), IL-31 (7.38), IFN-γ (13.55), TNF-α (12.00) and CXCL10 (11.18). Only one positive (IL-17E with TNF-α) and six negative (IL-1β, IL-17A and IL-17E with CXCL9, IL-10 with IL-17A, and IL-1β and IL-17A with CXCL10) correlations were found between these cytokines/chemokines. In conclusion, pro-inflammatory (IL-1α, IL-1β, IL-12, IL-13, IL-17A, IL-31, IFN-γ, TNF-α and CXCL10) and anti-inflammatory (IL-10 and IL-13) cytokines/chemokines were up-regulated in the serum of patients with mild/moderate COVID-19. Their potential as biomarkers for diagnosis and prognosis is suggested and the association with COVID-19 risk is indicated to give more insight on COVID-19 immunological responses among non-hospitalized patients.

Review of Immunologic Manifestations of COVID-19 Infection and Vaccination

We herein summarize currently available and clinically relevant information regarding the human immune responses to SARS-CoV-2 infection and vaccination, in relation to COVID-19 outcomes with a focus on acute respiratory distress syndrome (ARDS) and myocarditis.

The roles of critical pro-inflammatory cytokines in the drive of cytokine storm during SARS-CoV-2 infection

In patients with severe COVID-19, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), and even mortality can result from cytokine storm, which is a hyperinflammatory medical condition caused by the excessive and uncontrolled release of pro-inflammatory cytokines. High levels of numerous crucial pro-inflammatory cytokines, such as interleukin-1 (IL-1), IL-2, IL-6, tumor necrosis factor-α, interferon (IFN)-γ, IFN-induced protein 10 kDa, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein-1, and IL-10 and so on, have been found in severe COVID-19. They participate in cascade amplification pathways of pro-inflammatory responses through complex inflammatory networks. Here, we review the involvements of these critical inflammatory cytokines in SARS-CoV-2 infection and discuss their potential roles in triggering or regulating cytokine storm, which can help to understand the pathogenesis of severe COVID-19. So far, there is rarely effective therapeutic strategy for patients with cytokine storm besides using glucocorticoids, which is proved to result in fatal side effects. Clarifying the roles of key involved cytokines in the complex inflammatory network of cytokine storm will help to develop an ideal therapeutic intervention, such as neutralizing antibody of certain cytokine or inhibitor of some inflammatory signal pathways.

Comparison and monitoring of antibody response in convalescent and healthy vaccinated individuals against RBD and PCS of SARS-CoV-2 spike protein

The prevalence of SARS-CoV-2 as a global health threat has called for population-wide vaccination to curb COVID-19. Hence, the World Health Organization (WHO) has approved several platforms of SARS-CoV-2 vaccines for emergency use. Therefore, a more comprehensive study on the immune response induced by vaccines in diverse individuals is still required. Here, we expressed a local variant of SARS-CoV-2 receptor-binding domain (RBD) and protease cleavage site (PCS), playing a vital role in binding and fusion in Rosetta (DE3). We then characterized it through SDS-PAGE analysis and western blotting. Moreover, we compared and monitored ChAdOx1 nCoV-19 vaccination-induced antibody response in convalescent and healthy vaccinated individuals after the first and second vaccine doses through serologic assay against RBD and PCS, which have not yet been compared. We investigated a cohort of 100 sera samples; based on our parameters, 25 serum samples were selected as convalescent samples and 25 serum samples as healthy samples for comparison. These findings demonstrate that most of the convalescent sera show more reactivity with PCS (80%) than with RBD (56%). Interestingly, IgG antibody response against PCS was more significant in both pre- and post-vaccination in convalescent individuals than in healthy individuals. Indeed, anti-RBD antibody titers were most significant in pre-vaccination and post-first vaccination in convalescent individuals than in healthy individuals and not in pre-vaccination and post-second vaccination. Besides monitoring IgG antibody response against COVID-19, these findings could shed light on the progress, assessment, and efficacy evaluation of SARS-CoV-2 vaccines.Communicated by Ramaswamy H. Sarma.

Th-1, Th-2, Th-9, Th-17, Th-22 type cytokine concentrations of critical COVID-19 patients after treatment with Remdesivir

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread around the world causing a pandemic known as coronavirus disease 2019 (COVID-19). Cytokine storm was directly correlated with severity of COVID-19 syndromes. We evaluated the levels of 13 cytokines in ICU hospitalized COVID-19 patients (n=29) before, and after treatment with Remdesivir as well as in healthy controls (n=29). Blood samples were obtained from ICU patients during ICU admission (before treatment) and 5 days after treatment with Remdesivir. A group of 29 age- and gender-matched healthy controls was also studied. Cytokine levels were evaluated by multiplex immunoassay method using a fluorescence labeled cytokine panel. In comparison to cytokine levels measured at ICU admission, serum levels were reduced of IL-6 (134.75 pg/mL vs. 20.73 pg/mL, P< 0.0001), TNF-α (121.67 pg/mL vs. 10.15 pg/mL, P< 0.0001) and IFN-γ (29.69 pg/mL vs. 22.27 pg/mL, P= 0.005), whereas serum level was increased of IL-4 (8.47 pg/mL vs. 12.44 pg/mL, P= 0.002) within 5 days after Remdesivir treatment. Comparing with before treatment, Remdesivir significantly reduced the levels of inflammatory (258.98 pg/mL vs. 37.43 pg/mL, P< 0.0001), Th1-type (31.24 pg/mL vs. 24.46 pg/mL, P= 0.007), and Th17-type (36.79 pg/mL vs. 26.22 pg/mL, P< 0.0001) cytokines in critical COVID-19 patients. However, after Remdesivir treatment, the concentrations of Th2-type cytokines were significantly higher than before treatment (52.69 pg/mL vs. 37.09 pg/mL, P< 0.0001). In conclusion, Remdesivir led to decrease levels of Th1-type and Th17-type cytokines and increase Th2-type cytokines in critical COVID-19 patients 5 days after treatment.

Shedding Lights on the Extracellular Vesicles as Functional Mediator and Therapeutic Decoy for COVID-19

COVID-19 is an infectious disease caused by the novel coronavirus (SARS-CoV-2) that first appeared in late 2019 and has since spread across the world. It is characterized by symptoms such as fever, cough, and shortness of breath and can lead to death in severe cases. To help contain the virus, measures such as social distancing, handwashing, and other public health measures have been implemented. Vaccine and drug candidates, such as those developed by Pfizer/BioNTech, AstraZeneca, Moderna, Novavax, and Johnson & Johnson, have been developed and are being distributed worldwide. Clinical trials for drug treatments such as remdesivir, dexamethasone, and monoclonal antibodies are underway and have shown promising results. Recently, exosomes have gained attention as a possible mediator of the COVID-19 infection. Exosomes, small vesicles with a size of around 30-200 nm, released from cells, contain viral particles and other molecules that can activate the immune system and/or facilitate viral entry into target cells. Apparently, the role of exosomes in eliciting various immune responses and causing tissue injury in COVID-19 pathogenesis has been discussed. In addition, the potential of exosomes as theranostic and therapeutic agents for the treatment of COVID-19 has been elaborated.

Immunity in SARS-CoV-2 Infection: Clarity or Mystery? A Broader Perspective in the Third Year of a Worldwide Pandemic

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its mechanisms have been thoroughly studied by researchers all over the world with the hope of finding answers that may aid the discovery of new treatment options or effective means of prevention. Still, over 2 years into the pandemic that is an immense burden on health care and economic systems, there seem to be more questions than answers. The character and multitude of immune responses elicited in coronavirus disease 2019 (COVID-19) vary from uncontrollable activation of the inflammatory system, causing extensive tissue damage and consequently leading to severe or even fatal disease, to mild or asymptomatic infections in the majority of patients, resulting in the unpredictability of the current pandemic. The aim of the study was to systematize the available data regarding the immune response to SARS-CoV-2, to provide some clarification among the abundance of the knowledge available. The review contains concise and current information on the most significant immune reactions to COVID-19, including components of both innate and adaptive immunity, with an additional focus on utilizing humoral and cellular responses as effective diagnostic tools. Moreover, the authors discussed the present state of knowledge on SARS-CoV-2 vaccines and their efficacy in cases of immunodeficiency.

COVID-19's immuno-pathology and cardiovascular diseases

The pandemic of COVID-19 in worldwide causes recent millions of morbidity and mortality in all countries and is the most important challenge in the world in recent years. Coronavirus is a single-stranded RNA virus and infection with COVID-19 leads to acute respiratory distress syndrome, lung inflammation, cytokine storm, and death. The other complications include endothelial dysfunction, activation of coagulation, thromboembolic events, and vascular disease. Cardiovascular complications such as myocardial and stroke ischemia, pulmonary thromboembolism, systemic arterial, and deep vein thrombosis were reported. In this review, we presented immuno-pathological mechanisms and the effects of COVID-19 on the cardiovascular system, heart, vessels, coagulation system, and molecular glance of immuno-inflammation to the COVID-19's pathology on the cardiovascular system.

Exploring the Role of Immune System and Inflammatory Cytokines in SARS-CoV-2 Induced Lung Disease: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative pathogen of coronavirus disease 19 (COVID-19). COVID-19 can manifest with a heterogenous spectrum of disease severity, from mild upper airways infection to severe interstitial pneumonia and devastating acute respiratory distress syndrome (ARDS). SARS-CoV-2 infection may induce an over activation of the immune system and the release of high concentrations of pro-inflammatory cytokines, leading to a "cytokine storm", a recognized pathogenetic mechanism in the genesis of SARS-CoV-2-induced lung disease. This overproduction of inflammatory cytokines has been recognized as a poor prognostic factor, since it can lead to disease progression, organ failure, ARDS and death. Moreover, the immune system shows dysregulated activity, particularly through activated macrophages and T-helper cells and in the co-occurrent exhaustion of lymphocytes. We carried out a non-systematic literature review aimed at providing an overview of the current knowledge on the pathologic mechanisms played by the immune system and the inflammation in the genesis of SARS-CoV-2-induced lung disease. An overview on potential treatments for this harmful condition and for contrasting the "cytokine storm" has also been presented. Finally, a look at the experimented experimental vaccines against SARS-CoV-2 has been included.

Coagulopathy and the humoral response against viral proteins in patients at different stages of COVID-19

BACKGROUND

Patients with severe coronavirus disease 2019 (COVID-19) often present with coagulopathies and have high titres of circulating antibodies against viral proteins.

OBJECTIVES

Herein, we evaluated the association between D-dimer and circulating immunoglobulin levels against viral proteins in patients at different clinical stages of COVID-19.

METHODS

For this, we performed a cross-sectional study involving patients of the first wave of COVID-19 clinically classified as oligosymptomatic (n = 22), severe (n = 30), cured (n = 27) and non-infected (n = 9). Next, we measured in the plasma samples the total and fraction of immunoglobulins against the nucleoprotein (NP) and the receptor-binding domain (RBD) of the spike proteins by enzyme-linked immunosorbent assay (ELISA) assays.

FINDINGS

Patients with severe disease had a coagulation disorder with high levels of D-dimer as well as circulating IgG against the NP but not the RBD compared to other groups of patients. In addition, high levels of D-dimer and IgG against the NP and RBD were associated with disease severity among the patients in this study.

MAIN CONCLUSIONS

Our data suggest that IgG against NP and RBD participates in the worsening of COVID-19. Although the humoral response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is partially understood, and more efforts are needed to clarify gaps in the knowledge of this process.

Herd Immunity to Fight Against COVID-19: A Narrative Review

The advent of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its consequent illness, coronavirus disease 2019 (COVID-19), has revealed the severe impact of new, contagious pathogens on the population throughout the globe. Here, we describe the fundamental notions of herd immunity and discuss their consequences from the perspective of COVID-19, along with the obstacles to acquiring herd immunity. SARS-CoV-2 causes COVID-19, a contagious respiratory infection. It is a major global health issue, with more than 179 million positive cases and 3.8 million deaths globally. It has impacted more than 159 countries; hence, the World Health Organization designated it a pandemic. Different vaccines have been developed against coronavirus to slow the spread of this deadly virus. Immunizing people against coronavirus is the key to getting through this infectious virus. The central concept of this review article is the effect of vaccinating a large population to achieve herd immunity and the reasons for the delay in developing herd immunity. Herd immunity can prove highly beneficial for dealing with reinfection. Moreover, it can reduce the severity of the reinfection in many people who are twice infected with COVID-19. Herd immunity can prevent people in the high-risk group such as immunocompromised individuals; those on immunosuppressants; organ transplant recipients; particular age groups such as neonates, infants, toddlers, and elderly; those with impaired immunity; those with anaphylaxis reactions; and people with chronic diseases. However, due to repeated mutations of the virus, it is evolving into new strains with more severity. Its consequences on the immune system and response to a vaccine are still a big challenge to overcome. How new variants of COVID-19 impacted herd immunity needs to be investigated. The duration required for the development of herd immunity and how long it would last is still under research, along with the number of doses needed, booster doses, and the proportion of the population to be vaccinated.

Retinoic acid-inducible gene 1 (RIG-1) and IFN-β promoter stimulator-1 (IPS-1) significantly down-regulated in the severe coronavirus disease 2019 (COVID-19)

INTRODUCTION

Retinoic acid-inducible gene 1 (RIG-1) and melanoma differentiation-associated protein 5 (MDA5) are the well-known cytoplasmic sensors that recognize microbial DNA or RNA and active down-stream molecules, including IFN-β promoter stimulator-1 (IPS-1) and receptor interacting protein 1 (RIP1). The roles played by the networked molecules on the infection with SARS-CoV-2 needs more investigations.

MATERIAL AND METHOD

In this project MDA5, RIG-1, IPS-1 and RIP1 mRNA levels were evaluated in 45 hospitalized patients suffering from coronavirus disease of 2019 (COVID-19) and 45 healthy subjects using Real Time-qPCR technique.

RESULT

The results showed significant decreased RIG-1 and IPS-1 in the SARS-CoV-2 infected patients when compared to healthy cases. MDA5 and RIP1 did not change when compared two groups. Male patients had similar expression of MDA5, RIG-1, IPS-1 and RIP1 when compared to female patients.

CONCLUSION

Based on the results, it seems that RIG-1 and its signaling molecule, IPS-1, play key roles in the peripheral blood immune cells against SARS-CoV-2 and, their down-regulation may be induced by the virus to escape from immune responses.

Effectiveness of Hyperbaric Oxygen Therapy in SARS-CoV-2 Pneumonia: The Primary Results of a Randomised Clinical Trial

Mortality in COVID-19 is mainly associated with respiratory failure, cytokine storm, and macrophage activation. Oxygenation and anti-inflammatory effects of Hyperbaric Oxygen Therapy (HBOT) suggest that it is a promising adjunct treatment for COVID-19. Repeated sessions of HBO with standard COVID-19 therapy were used to reduce the inflammation and increase oxygenation. We evaluated the safety and efficacy of HBOT in avoiding the replacement ventilation and/or ECMO and its effect on the inflammatory process. Twenty-eight moderate-to-severe COVID-19 patients were randomized into control or HBOT group. HBOT patients participated in 5 hyperbaric sessions (60 min). Before and after each session blood gas levels and vital parameters were monitored. Blood samples were collected for extended biochemical tests, blood morphology and immunological assays. There were 3 deaths in the control, no deaths in the HBOT group. No adverse events leading to discontinuation of HBOT were observed and patients receiving HBOT required lower oxygen delivery. We observed decrease in CRP, ferritin and LDH and increase in CD3 in HBOT group compared to control. This study confirmed the feasibility and safety of HBOT in patients with COVID-19 and indicated HBOT can lead to alleviation of inflammation and partial restoration of T cell responses.

Can Lactoferrin, a Natural Mammalian Milk Protein, Assist in the Battle against COVID-19?

Notwithstanding mass vaccination against specific SARS-CoV-2 variants, there is still a demand for complementary nutritional intervention strategies to fight COVID-19. The bovine milk protein lactoferrin (LF) has attracted interest of nutraceutical, food and dairy industries for its numerous properties-ranging from anti-viral and anti-microbial to immunological-making it a potential functional ingredient in a wide variety of food applications to maintain health. Importantly, bovine LF was found to exert anti-viral activities against several types of viruses, including certain SARS-CoV-2 variants. LF's potential effect on COVID-19 patients has seen a rapid increase of in vitro and in vivo studies published, resulting in a model on how LF might play a role during different phases of SARS-CoV-2 infection. Aim of this narrative review is two-fold: (1) to highlight the most relevant findings concerning LF's anti-viral, anti-microbial, iron-binding, immunomodulatory, microbiota-modulatory and intestinal barrier properties that support health of the two most affected organs in COVID-19 patients (lungs and gut), and (2) to explore the possible underlying mechanisms governing its mode of action. Thanks to its potential effects on health, bovine LF can be considered a good candidate for nutritional interventions counteracting SARS-CoV-2 infection and related COVID-19 pathogenesis.

SARS-CoV-2 Specific Humoral Immune Responses after BNT162b2 Vaccination in Hospital Healthcare Workers

BACKGROUND

COVID-19 pandemic has led to a loss of human life in millions and devastating socio-economic consequences worldwide. So far, vaccination is the most effective long-term strategy to control and prevent severe COVID-19 disease. The aim of the current study was to evaluate the humoral immune responses raised against the BNT162b2 vaccine in hospital healthcare workers.

METHODS

Total number of 173 healthcare workers enrolled in the study. Their blood samples were collected in three different time intervals after the second SARS-CoV-2 vaccination and evaluated by the ELISA method to detect anti-spike protein IgM and IgG antibodies. The baseline characteristics of all participants were collected using questionnaires and were evaluated for finding any significant data.

RESULTS

Our results demonstrated that the levels of antibodies were higher in the young group (21-30 years old) and also among male participants. Moreover, the highest levels of antibodies were detected from the group that received the third shot vaccination.

CONCLUSIONS

Our results indicate that age, gender and third-dose vaccination can affect the levels of humoral immune responses against the BNT162b2 vaccine in healthcare workers.

Antiviral Potential of Plants against COVID-19 during Outbreaks-An Update

Several human diseases are caused by viruses, including cancer, Type I diabetes, Alzheimer's disease, and hepatocellular carcinoma. In the past, people have suffered greatly from viral diseases such as polio, mumps, measles, dengue fever, SARS, MERS, AIDS, chikungunya fever, encephalitis, and influenza. Recently, COVID-19 has become a pandemic in most parts of the world. Although vaccines are available to fight the infection, their safety and clinical trial data are still questionable. Social distancing, isolation, the use of sanitizer, and personal productive strategies have been implemented to prevent the spread of the virus. Moreover, the search for a potential therapeutic molecule is ongoing. Based on experiences with outbreaks of SARS and MERS, many research studies reveal the potential of medicinal herbs/plants or chemical compounds extracted from them to counteract the effects of these viral diseases. COVID-19's current status includes a decrease in infection rates as a result of large-scale vaccination program implementation by several countries. But it is still very close and needs to boost people's natural immunity in a cost-effective way through phytomedicines because many underdeveloped countries do not have their own vaccination facilities. In this article, phytomedicines as plant parts or plant-derived metabolites that can affect the entry of a virus or its infectiousness inside hosts are described. Finally, it is concluded that the therapeutic potential of medicinal plants must be analyzed and evaluated entirely in the control of COVID-19 in cases of uncontrollable SARS infection.

Unpacking COVID-19 Systems Biology in Lung and Whole Blood with Transcriptomics and miRNA Regulators

COVID-19 is a systemic disease affecting tissues and organs, including and beyond the lung. Apart from the current pandemic context, we also have vastly inadequate knowledge of consequences of repeated exposures to SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the virus causing COVID-19, in multiple organ systems and the whole organism scales when the disease evolves from a pandemic to an endemic state. This calls for a systems biology and systems medicine approach and unpacking the effects of COVID-19 in lung as well as other tissues. We report here original findings from transcriptomics analyses and differentially expressed genes (DEGs) in lung samples from 60 patients and 27 healthy controls, and in whole blood samples from 255 patients and 103 healthy individuals. A total of 11 datasets with RNA-seq transcriptomic data were obtained from the Gene Expression Omnibus and the European Nucleotide Archive. The identified DEGs were used to construct protein interaction and functional networks and to identify related pathways and miRNAs. We found 35 DEGs common between lung and the whole blood, and importantly, 2 novel genes, namely CYP1B1 and TNFAIP6, which have not been previously implicated with COVID-19. We also identified four novel miRNA potential regulators, hsa-mir-192-5p, hsa-mir-221-3p, hsa-mir-4756-3p, and hsa-mir-10a-5p, implicated in lung or other diseases induced by coronaviruses. In summary, these findings offer new molecular leads and insights to unpack COVID-19 systems biology in a whole organism context and might inform future antiviral drug, diagnostics, and vaccine discovery efforts.

Impact of the New Coronavirus Infection on the Immune System of Children and Adolescents in the Region of the Russian Federation

The emergence of COVID-19 (SARS-CoV-2) has presented public health professionals with new challenges in the diagnosis of the disease and treatment of patients. Nowadays, the epidemiology, clinical features, prevention and treatment of the disease are studied poorly due to continuous mutation of the pathogen. One of the consequences of the new coronavirus infection could be changes in the immune system of the human population. A detailed analysis of the immunological status of different racial groups under the influence of the new coronavirus infection is currently studied insufficiently, making this work of particular relevance. There is also a reluctance among some Russian residents to be vaccinated, including the population of Perm Krai, due to a lack of research on possible deviations in cellular immunity due to SARS-CoV-2 vaccination. At the start of the third wave caused by the new coronavirus infection, only 40% of the Russian population had been vaccinated, which was insufficient to acquire collective immunity. In the autumn of 2021, a QR code measure was introduced for vaccinated residents, which resulted in exceeding the necessary barrier for acquiring collective immunity. Due to the high growth and severity of the disease, we analysed the immunograms of children and adolescents, aged from 5 months to 17 years, in Perm Krai during the pandemic years 2020-2021. The patients' immunological status results were divided into three categories. Laboratory diagnosis of the human immune system was carried out using serological and flow cytophotometric analyses. A total of 247 samples were analysed. The aim of this work was to investigate changes in the immune system of children and adolescents during the pandemic caused by the new coronavirus infection. The methodology was based on the analysis of immunograms, including biochemical studies, immune status and flow cytophotometric analysis. The immunograms were pre-sorted by IgA, IgM, IgG immunoglobulin status into four categories: absence of disease-k₁ in which IgA, IgM, IgG immunoglobulin values were within the reference interval, active disease stage-k₂ in which IgA, IgM immunoglobulins had gone beyond the reference interval, passive disease stage-k₃ characterised by IgG and IgM immunoglobulin status, and patient recovery process-k₄. In the immunograms, three immune status indicators were selected for further investigation: phagocytosis absolute value, phagocytic number and phagocytic index and five flow cytometry indices: leukocytes, lymphocytes, NK cells (CD16+CD56+), T helpers (CD3+CD4+) and CD4+/CD8+ immunoregulation index. A quantitative analysis of the deviations of these indicators from the reference intervals was performed in the three studied age groups of children and adolescents living in Perm Krai of the Russian Federation during the pandemic of 2020-2021.

Central and effector memory T cells in peripheral blood of patients with interstitial pneumonia: preliminary clues from a COVID-19 study

BACKGROUND

SARS-CoV-2 pre-existing T-cell immune reactivity can be present in some people. A general perturbation of the main peripheral lymphocyte subsets has been described in severe COVID-19 patients, but very few studies assessed the general memory T-cell homeostasis in the acute phase of COVID-19. Here, we performed a general analysis of the main memory T cell populations in the peripheral blood of patients admitted to the hospital for a confirmed or probable COVID-19 diagnosis.

METHODS

In this cross-sectional study, adult patients (aged ≥ 18 years) needing hospital admission for respiratory disease due to confirmed or probable COVID-19, were recruited before starting the therapeutic protocol for this disease. In addition to the assessment of the general lymphocyte subpopulations in the early phase of COVID-19, central memory T cells (Tm_centr cells: CD45RO+CCR7+) and effector memory T cells (Tm_eff cells: CD45RO+CCR7-) were assessed by multi-color flow cytometry, in comparison to a control group.

RESULTS

During the study period, 148 study participants were recruited. Among them, 58 patients turned out positive for SARS-CoV-2 PCR (including both patients with interstitial pneumonia [PCR+Pn+] and without this complication [PCR+Pn-]), whereas the remaining 90 patients resulted to be SARS-CoV-2 PCR negative, even though all were affected with interstitial pneumonia [PCR-Pn+]. Additionally, 28 control patients without any ongoing respiratory disease were recruited. A clear unbalance in the T memory compartment emerged from this analysis on the whole pool of T cells (CD3+ cells), showing a significant increase in Tm_centr cells and, conversely, a significant decrease in Tm_eff cells in both pneumonia groups (PCR+Pn+ and PCR-Pn+) compared to the controls; PCR+Pn- group showed trends comprised between patients with pneumonia (from one side) and the control group (from the other side). This perturbation inside the memory T cell compartment was also observed in the individual analysis of the four main T cell subpopulations, based upon the differential expression of CD4 and/or CD8 markers.

CONCLUSION

Overall, we observed both absolute and relative increases of Tm_centr cells and decrease of Tm_eff cells in patients affected with interstitial pneumonia (regardless of the positive or negative results of SARS-CoV-2 PCR), compared to controls. These results need confirmation from additional research, in order to consider this finding as a potential biological marker of interstitial lung involvement in patients affected with viral respiratory infections.