Immunogenetic Association Underlying Severe COVID-19

Interaction Between Genetic Susceptibility and COVID-19 Pathogenesis in Pediatric Multisystem Inflammatory Disorders: The Role of Immune Responses

Numerous studies have highlighted the emergence of coronavirus disease (COVID-19) symptoms reminiscent of Kawasaki disease in children, including fever, heightened multisystem inflammation, and multiorgan involvement, posing a life-threatening complication. Consequently, extensive research endeavors in pediatric have aimed to elucidate the intricate relationship between COVID-19 infection and the immune system. COVID-19 profoundly impacts immune cells, culminating in a cytokine storm that particularly inflicts damage on the pulmonary system. The gravity and vulnerability to COVID-19 are closely intertwined with the vigor of the immune response. In this context, the human leukocyte antigen (HLA) molecule assumes pivotal significance in shaping immune responses. Genetic scrutiny of HLA has unveiled the presence of at least one deleterious allele in children afflicted with multisystem inflammatory syndrome in children (MIS-C). Furthermore, research has demonstrated that COVID-19 exploits the angiotensin-converting enzyme 2 (ACE-2) receptor, transmembrane serine protease type 2, and various other genes to gain entry into host cells, with individuals harboring ACE-2 polymorphisms being at higher risk. Pediatric studies have employed diverse genetic methodologies, such as genome-wide association studies (GWAS) and whole exome sequencing, to scrutinize target genes. These investigations have pinpointed two specific genomic loci linked to the severity and susceptibility of COVID-19, with the HLA locus emerging as a notable risk factor. In this comprehensive review article, we endeavor to assess the available evidence and consolidate data, offering insights into current clinical practices and delineating avenues for future research. Our objective is to advance early diagnosis, stabilization, and appropriate management strategies to mitigate genetic susceptibility's impact on the incidence of COVID-19 in pediatric patients with multisystem inflammation.

Healthcare Workers' Assessment of a Visual Triage System (VTS)

Overcrowding and extended waiting times in the emergency department (ED) can pose a significant risk of COVID-19 transmission from patients to healthy individuals. In 2017, the Saudi Ministry of Health (MOH) introduced a visual triage system (VTS) with scoring to notify healthcare workers (HCWs) in EDs about the Middle East respiratory syndrome coronavirus (MERS-CoV) infection risk. During the COVID-19 pandemic, the MOH employed a VTS to classify patients according to their potential risk of COVID-19 infection upon their admission to the ED. Suspected patients were then directed along specific pathways to reduce their contact with healthy individuals. This study assessed HCWs' satisfaction with the VTS in the ED of two major government hospitals within the Riyadh region. Additionally, it assessed HCWs' perceptions of VTS effectiveness. This study used a cross-sectional, observational design and relied on surveys for data collection. A total of 127 participants completed the survey, of which 87 (68.5%) were based in the EDs of the two hospitals. Among the ED participants, 18.1% expressed satisfaction with the VTS, 46.4% were neutral, and 33.1% reported dissatisfaction. ED participants provided feedback on the system's effectiveness, with 24.1% finding it effective, 66.7% considering it somewhat effective, and 9.2% deeming it ineffective. Of the total (127) study participants (70.1%) reported that the HCWs required better training to effectively implement the VTS infection control plans for suspected cases. Fewer than half of the participants (35.4%) deemed the time spent by VTS personnel to identify COVID-19 cases to be reasonable, whereas 22% found it too short and 27.6% considered it too long. Of the total 127 participants, 63% reported that language differences between patients and HCWs constituted barriers to the effective application of the VTS. Our study findings indicated that most ED participants had a neutral outlook on their satisfaction with the VTS and a neutral perspective on the effectiveness of VTS, viewing it as only somewhat effective. Reported weaknesses and key obstacles to the successful implementation of the VTS included language barriers. and insufficient training for HCWs, and unclear VTS pathways. The reported strengths of the VTS included its effectiveness in reducing crowds and identification of COVID-19 patients.

Effects of Epitranscriptomic RNA Modifications on the Catalytic Activity of the SARS-CoV-2 Replication Complex

SARS-CoV-2 causes individualized symptoms. Many reasons have been given. We propose that an individual's epitranscriptomic system could be responsible as well. The viral RNA genome can be subject to epitranscriptomic modifications, which can be different for different individuals, and thus epitranscriptomics can affect many events including RNA replication differently. In this context, we studied the effects of modifications including pseudouridine (Ψ), 5-methylcytosine (m5 C), N6-methyladenosine (m6 A), N1-methyladenosine (m1 A) and N3-methylcytosine (m3 C) on the activity of SARS-CoV-2 replication complex (SC2RC). We found that Ψ, m5 C, m6 A and m3 C had little effect, whereas m1 A inhibited the enzyme. Both m1 A and m3 C disrupt canonical base pairing, but they had different effects. The fact that m1 A inhibits SC2RC implies that the modification can be difficult to detect. This fact also implies that individuals with upregulated m1 A including cancer, obesity and diabetes patients might have milder symptoms. However, this contradicts clinical observations. Relevant discussions are provided.

Molecular Understanding of ACE-2 and HLA-Conferred Differential Susceptibility to COVID-19: Host-Directed Insights Opening New Windows in COVID-19 Therapeutics

The genetic variants of HLAs (human leukocyte antigens) play a crucial role in the virus–host interaction and pathology of COVID-19. The genetic variants of HLAs not only influence T cell immune responses but also B cell immune responses by presenting a variety of peptide fragments of invading pathogens. Peptide cocktail vaccines produced by using various conserved HLA-A2 epitopes provoke substantial specific CD8+ T cell responses in experimental animals. The HLA profiles vary among individuals and trigger different T cell-mediated immune responses in COVID-19 infections. Those with HLA-C*01 and HLA-B*44 are highly susceptible to the disease. However, HLA-A*02:01, HLA-DR*03:01, and HLA-Cw*15:02 alleles show resistance to SARS infection. Understanding the genetic association of HLA with COVID-19 susceptibility and severity is important because it can help in studying the transmission of COVID-19 and its physiopathogenesis. The HLA-C*01 and B*44 allele pathways can be studied to gain insight into disease transmission and physiopathogenesis. Therefore, integrating HLA testing is suggested in the ongoing pandemic, which will help in the rapid identification of highly susceptible populations worldwide and possibly acclimate vaccine development. Therefore, understanding the correlation between HLA and SARS-CoV-2 is critical in opening new insights into COVID-19 therapeutics, based on previous studies conducted.

Severe COVID-19 versus multisystem inflammatory syndrome: comparing two critical outcomes of SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with diverse host response immunodynamics and variable inflammatory manifestations. Several immune-modulating risk factors can contribute to a more severe coronavirus disease 2019 (COVID-19) course with increased morbidity and mortality. The comparatively rare post-infectious multisystem inflammatory syndrome (MIS) can develop in formerly healthy individuals, with accelerated progression to life-threatening illness. A common trajectory of immune dysregulation forms a continuum of the COVID-19 spectrum and MIS; however, severity of COVID-19 or the development of MIS is dependent on distinct aetiological factors that produce variable host inflammatory responses to infection with different spatiotemporal manifestations, a comprehensive understanding of which is necessary to set better targeted therapeutic and preventative strategies for both.

Severe COVID-19 Illness and α1-Antitrypsin Deficiency: COVID-AATD Study

BACKGROUND

Epidemiologic studies have reported that the geographical distribution of the prevalence of allelic variants of serine protein inhibitor-A1 (SERPINA1) and severe cases of COVID-19 were similar.

METHODS

A multicenter, cross-sectional, observational study to evaluate the frequency of alpha-1 antitrypsin deficiency (AATD) in patients with COVID-19 and whether it was associated with having suffered severe COVID-19.

RESULTS

2022 patients who had laboratory-confirmed SARS-CoV-2 infection. Mutations associated with AATD were more frequent in severe COVID versus non-severe (23% vs. 18.8%, p = 0.022). The frequency of Pi*Z was 37.8/1000 in severe COVID versus 17.5/1000 in non-severe, p = 0.001. Having an A1AT level below 116 was more frequent in severe COVID versus non-severe (29.5% vs. 23.1, p = 0.003). Factors associated with a higher likelihood of severe COVID-19 were being male, older, smoking, age-associated comorbidities, and having an A1AT level below 116 mg/dL [OR 1.398, p = 0.003], and a variant of the SERPINA1 gene that could affect A1AT protein [OR 1.294, p = 0.022].

CONCLUSIONS

These observations suggest that patients with AATD should be considered at a higher risk of developing severe COVID-19. Further studies are needed on the role of A1AT in the prognosis of SARS-CoV-2 infection and its possible therapeutic role.

The causal relationship between circulating cytokines and critically ill COVID-19: A bidirectional Mendelian randomization analysis

Background

In this study, we performed a bidirectional mendelian randomization analysis on circulating cytokines and critically ill COVID-19.

Methods

Both the exposure and outcome data were obtained from public genome wide association study (GWAS) database. We extracted independent instrumental variables from exposure at genome level significance (P < 5 × 10⁻⁸). Wald ratio or inverse variance weighted (IVW) method were used for estimating the causal relationships between circulating cytokines and critically ill COVID-19.

Results

Only IL5 (cytokines to critically ill COVID-19 direction) and bNGF, IL8 (critically ill COVID-19 to cytokines direction) showed suggestive causal relations. However, these associations lost significance after FDR correction. Another validation data set of critically ill COVID-19 did not confirm these associations, either.

Conclusions

Our Mendelian randomization did not find causal relationships between analyzable circulating cytokines and critically ill COVID-19.

Association Between Genetic Predictors for C-Reactive Protein and Venous Thromboembolism With Severe Adverse Coronavirus Disease 2019 Outcomes

To assess if genetic predictors for C-reactive protein and risk of venous thromboembolism are associated with severe outcomes among individuals who tested positive for severe acute respiratory syndrome coronavirus 2.

DESIGN

Retrospective cohort study.

SETTING

U.K. Biobank.

PATIENTS OR SUBJECTS

U.K. Biobank participants with European ancestry who were recorded to have a positive polymerase chain reaction test result for severe acute respiratory syndrome coronavirus 2 between March 16, 2020, and August 14, 2020.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND MAIN RESULTS

We constructed separate genetic risk scores for C-reactive protein and venous thromboembolism consisting of 56 and 37 genetic variants that have been significantly associated with venous thromboembolism and C-reactive protein, respectively. Among 1,126 individuals who were diagnosed with coronavirus disease 2019, 48% had a coronavirus disease 2019-related hospitalization, 16% received critical care support, 10% had critical respiratory support, and 21% died from coronavirus disease 2019. Genetic predisposition to high C-reactive protein concentrations was marginally associated with a lower risk of death from coronavirus disease 2019 (odds ratio, 0.85; 95% CI, 0.73-1.00; p = 0.05). No other associations were significant.

CONCLUSIONS

Our results do not support associations between polygenic risk for elevated blood C-reactive protein concentrations or venous thromboembolism and severe coronavirus disease 2019 health outcomes. Thus, considering genetic predisposition associated with C-reactive protein concentrations or venous thromboembolism risk is not meaningful for predicting severe coronavirus disease 2019 health outcomes.

Prevalence and predictors of Post-Acute COVID-19 Syndrome (PACS) after hospital discharge: A cohort study with 4 months median follow-up

BACKGROUND

Post-acute COVID-19 syndrome (PACS) is an emerging healthcare burden. The risk factors associated with PACS remain largely unclear. The aim of this study was to evaluate the frequency of new or persistent symptoms in COVID-19 patients post hospital discharge and identify associated risk factors.

METHODS

Our prospective cohort comprised of PCR-confirmed COVID-19 patients admitted to King Fahad Medical City, Riyadh, Saudi Arabia between May and July 2020. The patients were interviewed through phone calls by trained physicians from 6 weeks up to 6 months post hospital discharge. Multivariate Cox proportional hazards and logistic regression models were used to examine for predictors associated with persistence of symptoms and non-return to baseline health.

RESULTS

222 COVID-19 patients responded to follow-up phone interviews after a median of 122 days post discharge. The majority of patients were men (77%) with mean age of 52.47 (± 13.95) years. 56.3% of patients complained of persistent symptoms; 66 (29.7%) experiencing them for >21 days and 64 (28.8%) reporting not having returned to their baseline health. Furthermore, 39 patients (17.6%) reported visiting an emergency room post discharge for COVID-19-related symptoms while 16 (7.2%) had required re-hospitalization. Shortness of breath (40.1%), cough (27.5%) and fatigue (29.7%) were the most frequently reported symptoms at follow-up. After multivariable adjustments, female gender, pre-existing hypertension and length of hospital stay were associated with an increased risk of new or persistent symptoms. Age, pre-existing lung disease and emergency room visits increased the likelihood of not fully recovering from acute COVID-19. Patients who were treated with interferon β-1b based triple antiviral therapy during hospital stay were less likely to experience new or persistent symptoms and more likely to return to their baseline health.

CONCLUSIONS

COVID-19 survivors continued to suffer from dyspnea, cough and fatigue at 4 months post hospital discharge. Several risk factors could predict which patients are more likely to experience PACS and may benefit from individualized follow-up and rehabilitation programs.

Functional convalescent plasma antibodies and pre-infusion titers shape the early severe COVID-19 immune response

Transfer of convalescent plasma (CP) had been proposed early during the SARS-CoV-2 pandemic as an accessible therapy, yet trial results worldwide have been mixed, potentially due to the heterogeneous nature of CP. Here we perform deep profiling of SARS-CoV-2-specific antibody titer, Fc-receptor binding, and Fc-mediated functional assays in CP units, as well as in plasma from hospitalized COVID-19 patients before and after CP administration. The profiling results show that, although all recipients exhibit expanded SARS-CoV-2-specific humoral immune responses, CP units contain more functional antibodies than recipient plasma. Meanwhile, CP functional profiles influence the evolution of recipient humoral immunity in conjuncture with the recipient's pre-existing SARS-CoV2-specific antibody titers: CP-derived SARS-CoV-2 nucleocapsid-specific antibody functions are associated with muted humoral immune evolution in patients with high titer anti-spike IgG. Our data thus provide insights into the unexpected impact of CP-derived functional anti-spike and anti-nucleocapsid antibodies on the evolution of SARS-CoV-2-specific response following severe infection.

Perforin, COVID-19 and a possible pathogenic auto-inflammatory feedback loop

During COVID‐19 infection, reduced function of natural killer (NK) cells can lead to both compromised viral clearance and dysregulation of the immune response. Such dysregulation leads to overproduction of cytokines, a raised neutrophil/lymphocyte ratio and monocytosis. This in turn increases IL‐6 expression, which promotes scar and thrombus formation. Excess IL‐6 also leads to a further reduction in NK function through downregulation of perforin expression, therefore forming a pathogenic auto‐inflammatory feedback loop. The perforin/granzyme system of cytotoxicity is the main mechanism through which NK cells and cytotoxic T lymphocytes eliminate virally infected host cells, as well as being central to their role in regulating immune responses to microbial infection. Here, we present epidemiological evidence suggesting an association between perforin expression and resistance to COVID‐19. In addition, we outline the manner in which a pathogenic auto‐inflammatory feedback loop could operate and the relationship of this loop to genes associated with severe COVID‐19. Such an auto‐inflammatory loop may be amenable to synergistic multimodal therapy.

Immunometabolic Dysregulation at the Intersection of Obesity and COVID-19

Obesity prevails worldwide to an increasing effect. For example, up to 42% of American adults are considered obese. Obese individuals are prone to a variety of complications of metabolic disorders including diabetes mellitus, hypertension, cardiovascular disease, and chronic kidney disease. Recent meta-analyses of clinical studies in patient cohorts in the ongoing coronavirus-disease 2019 (COVID-19) pandemic indicate that the presence of obesity and relevant disorders is linked to a more severe prognosis of COVID-19. Given the significance of obesity in COVID-19 progression, we provide a review of host metabolic and immune responses in the immunometabolic dysregulation exaggerated by obesity and the viral infection that develops into a severe course of COVID-19. Moreover, sequela studies of individuals 6 months after having COVID-19 show a higher risk of metabolic comorbidities including obesity, diabetes, and kidney disease. These collectively implicate an inter-systemic dimension to understanding the association between obesity and COVID-19 and suggest an interdisciplinary intervention for relief of obesity-COVID-19 complications beyond the phase of acute infection.

Correlation between α1-Antitrypsin Deficiency and SARS-CoV-2 Infection: Epidemiological Data and Pathogenetic Hypotheses

The most common hereditary disorder in adults, α1-antitrypsin deficiency (AATD), is characterized by reduced plasma levels or the abnormal functioning of α1-antitrypsin (AAT), a major human blood serine protease inhibitor, which is encoded by the SERine Protein INhibitor-A1 (SERPINA1) gene and produced in the liver. Recently, it has been hypothesized that the geographic differences in COVID-19 infection and fatality rates may be partially explained by ethnic differences in SERPINA1 allele frequencies. In our review, we examined epidemiological data on the correlation between the distribution of AATD, SARS-CoV-2 infection, and COVID-19 mortality rates. Moreover, we described shared pathogenetic pathways that may provide a theoretical basis for our epidemiological findings. We also considered the potential use of AAT augmentation therapy in patients with COVID-19.

The unfolding palette of COVID-19 multisystemic syndrome and its neurological manifestations

Although our current knowledge of the pathophysiology of COVID-19 is still fragmentary, the information so far accrued on the tropism and life cycle of its etiological agent SARS-CoV-2, together with the emerging clinical data, suffice to indicate that the severe acute pulmonary syndrome is the main, but not the only manifestation of COVID-19. Necropsy studies are increasingly revealing underlying endothelial vasculopathies in the form of micro-haemorrhages and micro-thrombi. Intertwined with defective antiviral responses, dysregulated coagulation mechanisms, abnormal hyper-inflammatory reactions and responses, COVID-19 is disclosing a wide pathophysiological palette. An additional property in categorising the disease is the combination of tissue (e.g. neuro- and vasculo-tropism) with organ tropism, whereby the virus preferentially attacks certain organs with highly developed capillary beds, such as the lungs, gastrointestinal tract, kidney and brain. These multiple clinical presentations confirm that the acute respiratory syndrome as described initially is increasingly unfolding as a more complex nosological entity, a multiorgan syndrome of systemic breadth. The neurological manifestations of COVID-19, the focus of this review, reflect this manifold nature of the disease.

An integrative multiomics analysis identifies putative causal genes for COVID-19 severity

Purpose

It is critical to identify putative causal targets for SARS coronavirus 2, which may guide drug repurposing options to reduce the public health burden of COVID-19.

Methods

We applied complementary methods and multiphased design to pinpoint the most likely causal genes for COVID-19 severity. First, we applied cross-methylome omnibus (CMO) test and leveraged data from the COVID-19 Host Genetics Initiative (HGI) comparing 9,986 hospitalized COVID-19 patients and 1,877,672 population controls. Second, we evaluated associations using the complementary S-PrediXcan method and leveraging blood and lung tissue gene expression prediction models. Third, we assessed associations of the identified genes with another COVID-19 phenotype, comparing very severe respiratory confirmed COVID versus population controls. Finally, we applied a fine-mapping method, fine-mapping of gene sets (FOGS), to prioritize putative causal genes.

Results

Through analyses of the COVID-19 HGI using complementary CMO and S-PrediXcan methods along with fine-mapping, XCR1, CCR2, SACM1L, OAS3, NSF, WNT3, NAPSA, and IFNAR2 are identified as putative causal genes for COVID-19 severity.

Conclusion

We identified eight genes at five genomic loci as putative causal genes for COVID-19 severity.

COVID-19 and Malignancy: Exploration of the possible genetic and epigenetic interlinks and overview of the vaccination scenario

BACKGROUND

Malignancy is one of the prime global causes of mortality. Cancer Patients suffering from SARS-CoV-2 have demonstrated higher rates of severe complications exacerbating towards death. Possible genetic and epigenetic alterations may exist in cancer patients which have the potential to contribute towards their increased vulnerability towards COVID-19.

METHOD

An exhaustive literature search using 'COVID-19', 'SARS-CoV-2', 'Cancer', 'Malignancy', 'Relationships', Interlinks', 'Genetic', 'Epigenetic', 'Epidemiological studies', 'Clinical Studies', 'Vaccination', 'Vaccine scenario' were conducted in PubMed and EMBASE till 2nd June 2021.

RESULT

In this narrative review, 17 epidemiological studies were listed which focused on clinical parameters of several malignancy patient cohorts who contracted COVID-19. Besides, genetic and epigenetic alterations seen among cancer patients are also discussed which may plausibly increase the vulnerability of cancer patients to SARS-CoV-2 infection. Also, global vaccination scenario among malignant patients along with the necessity to prioritize them in the vaccination campaigns are also elaborated.

CONCLUSION

Genetic and epigenetic modifications present in ACE2, TMPRSS2, IL-6 and several cytokines require more in-depth research to elucidate the shared mechanisms of malignancy and SARS-CoV-2.

Combination of (interferon beta-1b, lopinavir/ritonavir and ribavirin) versus favipiravir in hospitalized patients with non-critical COVID-19: A cohort study

Objectives

Our study aims at comparing the efficacy and safety of IFN-based therapy (lopinavir/ritonavir, ribavirin, and interferon β-1b) vs. favipiravir (FPV) in a cohort of hospitalized patients with non-critical COVID-19.

Methods

Single center observational study comparing IFN-based therapy (interferon β-1b, ribavirin, and lopinavir/ritonavir) vs. FPV in non-critical hospitalized COVID-19 patients. Allocation to either treatment group was non-random but based on changes to national treatment protocols rather than physicians’ selection (quasi-experimental). We examined the association between IFN-based therapy and 28-day mortality using Cox regression model with treatment as a time-dependent covariate.

Results

The study cohort included 222 patients, of whom 68 (28%) received IFN-based therapy. Antiviral therapy was started at a median of 5 days (3–6 days) from symptoms onset in the IFN group vs. 6 days (4–7 days) for the FPV group, P <0.0001. IFN-based therapy was associated with a lower 28-day mortality as compared to FPV (6 (9%) vs. 18 (12%)), adjusted hazard ratio [aHR] (95% Cl) = 0.27 (0.08–0.88)). No difference in hospitalization duration between the 2 groups, 9 (7–14) days vs. 9 (7–13) days, P = 0.732 was found. IFN treated group required less use of systemic corticosteroids (57%) as compared to FPV (77%), P = 0.005 after adjusting for disease severity and other confounders. Patients in the IFN treated group were more likely to have nausea and diarrhea as compared to FPV group (13%) vs. (3%), P = 0.013 and (18%) vs. (3%), P<0.0001, respectively.

Conclusion

Early IFN-based triple therapy was associated with lower 28-days mortality as compared to FPV.

Therapeutic strategies to fight COVID-19: Which is the status artis?

COVID‐19 is a complex disease, and many difficulties are faced today especially in the proper choice of pharmacological treatments. The role of antiviral agents for COVID‐19 is still being investigated and evidence for immunomodulatory and anti‐inflammatory drugs is quite conflicting, whereas the use of corticosteroids is supported by robust evidence. The use of heparins in hospitalized critically ill patients is preferred over other anticoagulants. There are conflicting data on the use of convalescent plasma and vitamin D. According to the World Health Organization (WHO), many vaccines are in Phase III clinical trials, and some of them have already received marketing approval in European countries and in the United States. In conclusion, drug repurposing has represented the main approach recently used in the treatment of patients with COVID‐19. At this moment, analysis of efficacy and safety data of drugs and vaccines used in real‐life context is strongly needed.

Do gene-environment interactions play a role in COVID-19 distribution? The case of Alpha-1 Antitrypsin, air pollution and COVID-19

Background

Gene-environment interactions are relevant for several respiratory diseases. This communication raises the hypothesis that the severity of COVID-19, a complex disease where the individual response to the infection may play a significant role, could partly result from a gene-environment interaction between air-pollution and Alpha-1 Antitrypsin (AAT) genes.

Methods

To evaluate the impact of the AAT and air pollution interaction on COVID-19, we introduced an AAT*air pollution global risk score summing together, in each country, an air pollution score (ozone, nitrogen dioxide and fine particulate matter) and an AAT score (which sums the ranked frequency of MZ, SZ, MS). We compared this global score with the ranking of European countries in terms of death number per million persons.

Results

The ranking of the AAT*air pollution global risk score matched the ranking of the countries in terms of the observed COVID-19 deaths per 1M inhabitants, namely in the case of the first European countries: Belgium, UK, Spain, Italy, Sweden, France. We observed parallelism between the number of COVID deaths and the AAT*air pollution global risk in Europe. AAT anti-protease, immune-modulating and coagulation-modulating activities may explain this finding, although very speculatively.

Conclusions

Even if further studies taking into account genetic background, population density, temporal dynamics of individual epidemics, access to healthcare, social disparities and immunological response to SARS-CoV2 are needed, our preliminary observation urges to open a discussion on gene-environment interactions in COVID-19.

Functional Antibodies in COVID-19 Convalescent Plasma

In the absence of an effective vaccine or monoclonal therapeutic, transfer of convalescent plasma (CCP) was proposed early in the SARS-CoV-2 pandemic as an easily accessible therapy. However, despite the global excitement around this historically valuable therapeutic approach, results from CCP trials have been mixed and highly debated. Unlike other therapeutic interventions, CCP represents a heterogeneous drug. Each CCP unit is unique and collected from an individual recovered COVID-19 patient, making the interpretation of therapeutic benefit more complicated. While the prevailing view in the field would suggest that it is administration of neutralizing antibodies via CCP that centrally provides therapeutic benefit to newly infected COVID-19 patients, many hospitalized COVID-19 patients already possess neutralizing antibodies. Importantly, the therapeutic benefit of antibodies can extend far beyond their simple ability to bind and block infection, especially related to their ability to interact with the innate immune system. In our work we deeply profiled the SARS-CoV-2-specific Fc-response in CCP donors, along with the recipients prior to and after CCP transfer, revealing striking SARS-CoV-2 specific Fc-heterogeneity across CCP units and their recipients. However, CCP units possessed more functional antibodies than acute COVID-19 patients, that shaped the evolution of COVID-19 patient humoral profiles via distinct immunomodulatory effects that varied by pre-existing SARS-CoV-2 Spike (S)-specific IgG titers in the patients. Our analysis identified surprising influence of both S and Nucleocapsid (N) specific antibody functions not only in direct antiviral activity but also in anti-inflammatory effects. These findings offer insights for more comprehensive interpretation of correlates of immunity in ongoing large scale CCP trials and for the design of next generation therapeutic design.

The Role of Immunogenetics in COVID-19

Coronavirus disease 2019 (COVID-19) is induced by SARS-CoV-2 and may arise as a variety of clinical manifestations, ranging from an asymptomatic condition to a life-threatening disease associated with cytokine storm, multiorgan and respiratory failure. The molecular mechanism behind such variability is still under investigation. Several pieces of experimental evidence suggest that genetic variants influencing the onset, maintenance and resolution of the immune response may be fundamental in predicting the evolution of the disease. The identification of genetic variants behind immune system reactivity and function in COVID-19 may help in the elaboration of personalized therapeutic strategies. In the frenetic look for universally shared treatment plans, those genetic variants that are common to other diseases/models may also help in addressing future research in terms of drug repurposing. In this paper, we discuss the most recent updates about the role of immunogenetics in determining the susceptibility to and the history of SARS-CoV-2 infection. We propose a narrative review of available data, speculating about lessons that we have learnt from other viral infections and immunosenescence, and discussing what kind of aspects of research should be deepened in order to improve our knowledge of how host genetic variability impacts the outcome for COVID-19 patients.

Epigenetic underpinnings of inflammation: Connecting the dots between pulmonary diseases, lung cancer and COVID-19

Inflammation is an essential component of several respiratory diseases, such as chronic obstructive pulmonary disease (COPD), asthma and acute respiratory distress syndrome (ARDS). It is central to lung cancer, the leading cancer in terms of associated mortality that has affected millions of individuals worldwide. Inflammation and pulmonary manifestations are also the major causes of COVID-19 related deaths. Acute hyperinflammation plays an important role in the COVID-19 disease progression and severity, and development of protective immunity against the virus is greatly sought. Further, the severity of COVID-19 is greatly enhanced in lung cancer patients, probably due to the genes such as ACE2, TMPRSS2, PAI-1 and furin that are commonly involved in cancer progression as well as SAR-CoV-2 infection. The importance of inflammation in pulmonary manifestations, cancer and COVID-19 calls for a closer look at the underlying processes, particularly the associated increase in IL-6 and other cytokines, the dysregulation of immune cells and the coagulation pathway. Towards this end, several reports have identified epigenetic regulation of inflammation at different levels. Expression of several key inflammation-related cytokines, chemokines and other genes is affected by methylation and acetylation while non-coding RNAs, including microRNAs as well as long non-coding RNAs, also affect the overall inflammatory responses. Select miRNAs can regulate inflammation in COVID-19 infection, lung cancer as well as other inflammatory lung diseases, and can serve as epigenetic links that can be therapeutically targeted. Furthermore, epigenetic changes also mediate the environmental factors-induced inflammation. Therefore, a better understanding of epigenetic regulation of inflammation can potentially help develop novel strategies to prevent, diagnose and treat chronic pulmonary diseases, lung cancer and COVID-19.

COVID-19-associated acute respiratory distress syndrome (CARDS): Current knowledge on pathophysiology and ICU treatment - A narrative review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces coronavirus-19 disease (COVID-19) and is a major health concern. Following two SARS-CoV-2 pandemic “waves,” intensive care unit (ICU) specialists are treating a large number of COVID19-associated acute respiratory distress syndrome (ARDS) patients. From a pathophysiological perspective, prominent mechanisms of COVID19-associated ARDS (CARDS) include severe pulmonary infiltration/edema and inflammation leading to impaired alveolar homeostasis, alteration of pulmonary physiology resulting in pulmonary fibrosis, endothelial inflammation (endotheliitis), vascular thrombosis, and immune cell activation.

Although the syndrome ARDS serves as an umbrella term, distinct, i.e., CARDS-specific pathomechanisms and comorbidities can be noted (e.g., virus-induced endotheliitis associated with thromboembolism) and some aspects of CARDS can be considered ARDS “atypical.” Importantly, specific evidence-based medical interventions for CARDS (with the potential exception of corticosteroid use) are currently unavailable, limiting treatment efforts to mostly supportive ICU care.

In this article, we will discuss the underlying pulmonary pathophysiology and the clinical management of CARDS. In addition, we will outline current and potential future treatment approaches.

Dysregulated Interferon Response Underlying Severe COVID-19

Innate immune interferons (IFNs), including type I and III IFNs, constitute critical antiviral mechanisms. Recent studies reveal that IFN dysregulation is key to determine COVID-19 pathogenesis. Effective IFN stimulation or prophylactic administration of IFNs at the early stage prior to severe COVID-19 may elicit an autonomous antiviral state, restrict the virus infection, and prevent COVID-19 progression. Inborn genetic flaws and autoreactive antibodies that block IFN response have been significantly associated with about 14% of patients with life-threatening COVID-19 pneumonia. In most severe COVID-19 patients without genetic errors in IFN-relevant gene loci, IFN dysregulation is progressively worsened and associated with the situation of pro-inflammation and immunopathy, which is prone to autoimmunity. In addition, the high correlation of severe COVID-19 with seniority, males, and individuals with pre-existing comorbidities will be plausibly explained by the coincidence of IFN aberrance in these situations. Collectively, current studies call for a better understanding of the IFN response regarding the spatiotemporal determination and subtype-specificity against SARS-CoV-2 infections, which are warranted to devise IFN-related prophylactics and therapies.

SARS-CoV-2 meta-interactome suggests disease-specific, autoimmune pathophysiologies and therapeutic targets

Background: Severe coronavirus disease 2019 (COVID-19) is associated with multiple comorbidities and is characterized by an auto-aggressive inflammatory state leading to massive collateral damage. To identify preventive and therapeutic strategies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it is important to ascertain the molecular interactions between virus and host, and how they translate into disease pathophysiology. Methods: We matched virus-human protein interactions of human coronaviruses and other respiratory viruses with lists of genes associated with autoimmune diseases and comorbidities associated to worse COVID-19 course. We then selected the genes included in the statistically significant intersection between SARS-CoV-2 network and disease associated gene sets, identifying a meta-interactome. We analyzed the meta-interactome genes expression in samples derived from lungs of infected humans, and their regulation by IFN-β. Finally, we performed a drug repurposing screening to target the network's most critical nodes. Results: We found a significant enrichment of SARS-CoV-2 interactors in immunological pathways and a strong association with autoimmunity and three prognostically relevant conditions (type 2 diabetes, coronary artery diseases, asthma), that present more independent physiopathological subnetworks. We observed a reduced expression of meta-interactome genes in human lungs after SARS-CoV-2 infection, and a regulatory potential of type I interferons. We also underscored multiple repurposable drugs to tailor the therapeutic strategies. Conclusions: Our data underscored a plausible genetic background that may contribute to the distinct observed pathophysiologies of severe COVID-19. Also, these results may help identify the most promising therapeutic targets and treatments for this condition.