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Background: Better understanding of host inflammatory changes that precede development of severe COVID-19 could improve delivery of available antiviral and immunomodulatory therapies, and provide insights for the development of new therapies. Method(s): In plasma from individuals with COVID-19, sampled <=10 days from symptom onset from the All-Ireland Infectious Diseases Cohort study, we measured 61 biomarkers, including markers of innate immune and T cell activation, coagulation, tissue repair, lung injury, and immune regulation. We used principal component analysis (PCA) and k-means clustering to derive biomarker clusters, and univariate and multivariate ordinal logistic regression to explore association between cluster membership and maximal disease severity, adjusting for risk factors for severe COVID-19, including age, sex, ethnicity, BMI, hypertension and diabetes. Result(s): From March 2020-April 2021, we included 312 individuals, (median (IQR) age 62 (48-77) years, 7 (4-9) days from symptom onset, 54% male) in the analysis. PCA and clustering derived 4 clusters. Compared to cluster 1, clusters 2-4 were significantly older and of higher BMI but there were no significant differences in sex or ethnicity. Cluster 1 had low levels of inflammation, cluster 2 had higher levels of markers of tissue repair and endothelial activation (EGF, VEGF, PDGF, TGFalpha, serpin E1 and p-selectin). Cluster 3 and 4 were both characterised by higher overall inflammation, but compared to cluster 4, cluster 3 had downregulation of growth factors, markers of endothelial activation, and immune regulation (IL10, PDL1), but higher alveolar epithelial injury markers (RAGE, ST2). In univariate analysis, compared to cluster 1, cluster 3 had the highest odds of severe disease (OR (95% CI) 9.02 (4.62-18.31), followed by cluster 4: 5.59 (2.75-11.72) then cluster 2: 4.5 (2.38-8.81), all p < 0.05). Cluster 3 remained most strongly associated with severe disease in fully adjusted analyses;cluster 3: OR(95% CI) 5.99 (2.69-13.35), cluster 2: 3.14 (1.54-6.42), cluster 4: 3.13 (1.36-7.19), all p< 0.05). Conclusion(s): Distinct early inflammatory profiles predicted maximal disease severity independent of known risk factors for severe COVID-19. A cluster characterised by downregulation of growth factor and endothelial markers and early evidence of alveolar injury was associated with highest risk of developing severe COVID19. Whether this reflects a dysregulated inflammatory response that could improve targeted treatment requires further study. Heatmap of biomarker derived clusters and forest plot of association between clusters and disease severity. A: Heatmap demonstrating differences in biomarkers between clusters B: Forest plot demonstrating odds ratio of specific clusters for progressing to moderate or severe disease (reference Cluster 1), calculated using ordinal logistic regression. Odds ratio (95% CI) presented as unadjusted and fully adjusted (for age, sex, ethnicity, BMI, hypertension, diabetes, immunosuppression, smoking and baseline anticoagulant use). Maximal disease severity graded per the WHO severity scale.
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Background: A considerable proportion of patients do not fully recover from COVID-19 infection and report symptoms that persist beyond the initial phase of infection: This condition is defined long-COVID-19 syndrome (LCS). LCS can involve lungs as well as several extrapulmonary organs, including the cardiovascular system. The risk and 1-year burden of cardiovascular diseases (CVD) is increased in COVID-19 survivors, even in subjects at low risk of CVD. Recently, we documented that acute COVID- 19 infection induces altered platelet activation state characterized by a prothrombotic phenotype and by the formation of platelet-leukocyte aggregates (PLA), that may be involved in the pulmonary microthrombi found in autoptic specimens. No data are yet available on the contribution of platelet activation to residual pulmonary impairment and procoagulant potential in LCS patients. Purpose(s): To study platelet activation status, microvesicle (MV) profile, platelet thrombin generation capacity (pTGC) in LCS patients enrolled at 6 months after resolution of the acute phase (6mo-FU), compared to acute COVID-19 infection patients. Method(s): 6mo-FU COVID-19 patients (n=24) with established LCS were enrolled at Centro Cardiologico Monzino. Residual pulmonary impairment was assessed by Cardiopulmonary Exercise Testing (CPET) and 64-rows- CT scan evaluation. Platelet activation (P-selectin, Tissue Factor [TF] and PLA) and MV profile were assessed by flow cytometry;pTGC by calibrated automated thrombogram. 46 patients enrolled during acute COVID-19 infection and 46 healthy subjects (HS) were used for comparison. Result(s): Dispnea in LCS patients was confirmed by CPET showing compromised alveolus-capillary membrane diffusion and residual pulmonary impairment. TF+-platelet and -MV levels were 3-fold (1.5% [1.2-2.9] vs 2.4% [1.6-5.7]) and 2-fold (217/mul [137-275] vs 435/mul [275-633]) lower at 6mo-FU compared to acute phase, being comparable to HS. pTGC behaved similarly. At 6mo-FU, the MV profile, in terms of total number and cell origin, returned to physiological levels. Conversely, although lower than that measured in acute phase, a 2.5-fold higher platelet P-selectin expression (6.9% [3-13.5] vs 11.7% [5.2-18.9]) and PLA formation (35.5% [27.4- 46.8] vs 67.7% [45.7-85.3]) was observed at 6mo-FU compared to HS. Interestingly, a significant correlation between PLA formation and residual pulmonary impairment was observed (r=-0.423;p=0.02). Conclusion(s): These data strengthen the hypothesis that the presence of PLA in the bloodstream, and thus also in the pulmonary microcirculation, may contribute to support pulmonary dysfunction still observed in LCS patients.
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The pathogenesis of severe coronavirus infection COVID-19 is associated with activation of immune system, cytokine storm, impaired blood clotting, microvascular thrombosis, organ ischemia and multiple organ dysfunction syndrome. The role of various lymphocyte subpopulations in COVID-19 is still debated. The aim of our study was to analyze the subpopulational profile of peripheral blood lymphocytes in COVID-19 patients as compared with healthy donors. The study included 20 COVID-19 patients (11 males and 9 females,) and 26 healthy donors. Average age of the patients was 52 and 56 years, respectively. Clinical examinations were performed by standard laboratory methods. Peripheral blood lymphocytes were isolated in the Ficoll gradient. The cells were stained with antibodies to specific antigens of main lymphocyte populations, endothelial cells, and apoptotic cell markers. The analysis was performed by flow cytometry. The results showed that all patients had elevated C-reactive protein (14- to 35-fold), ferritin (1.2- to 13-fold), D-dimers (1.2- to 90-fold). 55% of men had a decrease in the absolute number of lymphocytes, in women this index was at the low normal limit. Cytometric analysis showed that, among peripheral blood lymphocytes, the proportion of functional cells expressing the CD45 marker ranged from 2 to 12% in 70% of patients, as compared with 80-99% among the donors. The proportion of CD45+ lymphocytes significantly correlated with the level of hemoglobin, but not with the levels of inflammatory biochemical markers. Among the functional lymphocytes of patients, there was a decrease in the proportion of CD3+, CD4+, CD8+T cells, increased proportion of natural killer CD56+ and the apoptotic (AnnexinV+) cell contents, but the proportion of CD19 and HLA-DR+B cells was not changed. Analysis of the lymphocyte (LC) subpopulations that did not express CD45 marker showed that this fraction contained different lymphocyte subsets with reduced expression of CD4, CD8, CD19, CD56 etc. in the blood of patients and donors. Higher percentage of endothelial cells expressing CD62P marker made the difference between patients and donors. Laboratory determination of lymphocyte subsets in blood samples of COVID-19 patients does not reflect the real severity pattern of the disease, thus requiring studies of the CD45-expressing functional cell populations.Copyright © Svirshchevskaya E.V. et al., 2023 The article can be used under the Creative Commons Attribution 4.0 License.
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Objectives: The aim of this study was to explore the association of the plasma levels of coagulation proteins with venous thromboembolic events (VTE) in COVID-19 and identify candidate early markers of VTE. Background(s): Coagulopathy and thromboembolism are known complications of SARS-CoV-2 infection. The mechanisms of COVID-19-associated hematologic complications involve endothelial cell and platelet dysfunction and immunothrombosis and have been intensively studied. Yet, a full understanding of the pathogenesis and factors that lead to COVID-19 associated coagulopathy is lacking. Previous studies investigated only small numbers of coagulation proteins together, and they were limited in their ability to adjust for confounders. Method(s): This study was a post-hoc analysis of a previously published dataset (Filbin et al., 2021). We included in our analysis 305 subjects with confirmed SARS-CoV-2 infection who presented to an urban Emergency Department with acute respiratory distress during the first COVID-19 surge in 2020;13 (4.2%) were subsequently diagnosed with venous thromboembolism during hospitalization. Serial samples were obtained on days 0, 3, and 7 and assays were performed on two highly-multiplexed proteomic platforms, that in combination cover 1472 + 4776 proteins. We included 31 coagulation proteins in our analysis. Result(s): Nine coagulation proteins were differentially expressed in patients with thromboembolic events. In multivariable models, day 0 levels of P-selectin, a cell adhesion molecule on the surface of activated endothelial cells, displayed the strongest association with the diagnosis of VTE, independent of disease severity and other confounders (p=0.0025). P-selectin together with D-dimer upon hospital presentation provided better discriminative ability for VTE diagnosis than D-dimer alone (AUROC = 0.834 vs. 0.783). Conclusion(s): Our results suggest that plasma P-selectin is a potential early biomarker for the risk stratification of VTE in COVID-19 disease. Our findings support the importance of endothelial activation in the mechanistic pathway of venous thromboembolism in COVID-19.Copyright © 2023
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Purpose: Release and circulation of pro-inflammatory cytokines or “cytokine storm,” a pathophysiologic component of severe COVID-19, is associated with thrombosis and clot embolization. Compromised patients often require extracorporeal oxygenation and mechanical circulatory support (MCS), imparting blood flow disturbances and exogenous shear stress, further amplifying thrombotic potential. Central in these processes is the platelet. The dynamic interaction of MCS flow/shear and inflammatory cytokines and their propensity for altering platelet function remains unknown. We hypothesized that platelet function is modified in an MCS + pro-inflammatory cytokine environment. We examined platelet aggregation as a function of time, exposing platelets to COVID-19-associated cytokines under MCS flow in vitro. Methods: An Impella5.5® was affixed in a closed loop and positioned with outflow cannula in a 1-inch tube region, maintained at differential 60mmHg pressure. Alternatively, a CentriMag® was affixed in series with a similar closed loop. Porcine PRP, obtained via centrifugation of fresh, ACD-A anticoagulated whole blood was used as circulating fluid. A cytokine “COVID cocktail” of porcine IL-6 (4.5 ng/mL), IL-1β (0.5 ng/mL), IL-8 (2.7 ng/mL), and TNFα (1 ng/mL) was added to PRP and circulated at 5 L/ min. After 5, 60 and 240min of circulation, platelet samples were taken and measured for aggregation with ADP (20uM), and expression of activation markers (CD62P, AnnV) via flow cytometry. Samples were measured in duplicate from N ≥ 2 pigs per experiment. Results: The addition of COVID Cocktail cytokines led to an increase in overall aggregability of platelets over time. In contrast, the addition of shear via MCS devices led to a decrease in platelet aggregability despite Cytokine addition (Fig 1). Notably, platelet aggregability was more greatly reduced with CentriMag (85% reduction) than with Impella (65% reduction). There was no significant difference in platelet activation (AnnV binding, CD62P exposure) between CentriMag and Impella 5.5 in the cytokine environment. (Figure Presented).
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Background: Rheumatoid arthritis (RA) is the most common systemic autoimmune disease that primarily affects joints but is also often characterized by extra-articular involvement1. Cardiovascular diseases are the most important causes of sudden death in these patients, which present a risk of developing cardiovascular events increased by 48%2. The causes of increased cardiovascular risk are several and not completely understood, but recent evidence supports the key role of endothelial dysfunction in pathogenesis. In this complex scenario, it is known that IL-6 receptors are present at the endothelial level and can be activated leading to endothelial dysfunction. SARS-Cov-2 is a coronavirus responsible for the disease called 'coronavirus disease 2019' (CoViD-19) characterized by clinical manifestations ranging from a flu-like syndrome up to severe lung damage associated with systemic hyper cytokine syndrome that can lead to multiple organ failure and death. Therefore, both RA and Covid-19 are associated with an increased pro-thrombotic and cardiovascular risk and IL-6 might be crucial in the patho-physiological mechanisms of both diseases. Objectives: The main hypothesis of this study was to evaluate the possible role of IL-6 as a promoter of endothelial dysfunction in RA and CoViD-19. Methods: In vitro experiments were conducted on the endothelial cell line EA. hy926. Cells were treated for 24 h with fetal bovine serum (FBS), a pool of RA patients' sera or a pool of CoViD-19 patients' sera. The expression levels of adhesion molecules (V-CAM1/CD-106, I-CAM/CD-54, p-selectine/CD-62, tissue factor/CD-142) and apoptosis were analyzed using cytofuorimetric technique. In addition, the autophagy level, using the autophagy markers p62 and LC3II, were evaluated through a western-blot analysis. The same experiments were conducted co-treating cells with the same pool of sera in addition to tocilizumab (TCZ), an anti-IL-6 drug, to verify the reversibility of the process and test the role of the aforementioned cytokine. Data are reported as interquartile median values. The Kruskal Wallis test was used for unpaired samples and the Mann-Whitney test for paired samples. P<0.05 values were considered statistically signifcant. Results: EA. hy926 cells, when treated with both RA and CoViD-19 patients' sera, showed increased levels of activation molecules and apoptosis compared to FBS treated cells. In addition, we observed increased levels of both p62 and LC3 proteins after both rheumatoid arthritis and CoViD-19 patients' sera treatment. All these fndings were reversible in the presence of TCZ. The results are presented in Figure 1. Conclusion: Our data showed that treatment with RA and CoViD-19 patients' sera increase the activation and death of endothelial cells in vitro. The increased level of cells death is possibly due to a block of autophagy. The reversibility of the process after blocking IL-6 with TCZ co-treatment confrms the hypothesis that IL-6 can play a key role in the pathogenesis of endothelial damage in patients with RA and CoViD-19.
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Background: Inflammation and neutrophils play a central role in severe Covid-19 disease. In previous data, we showed that the FLARE score, combining both tumor and Covid-19-induced proinflammatory status (proinflamstatus), predicts early mortality in cancer patients (pts) with Covid-19 infection. We aimed to assess the impact of this score in a larger cohort and characterize the immunophenotype (IF) of circulating neutrophils. Methods: Multicenter retrospective cohort (RC) of pts with cancer and Covid-19 infection across 14 international centers. Circulating inflammatory markers were collected at two timepoints: baseline (-15 to -45d before Covid-19 diagnosis) and Covid-19 diagnosis. Tumor-induced proinflam-status was defined by high dNLR (neutrophils/(leucocytes-neutrophils)> 3) at baseline. Covid-19-induced proinflam-status was defined by +100% increase of dNLR between both timepoints. We built the FLARE score combining both Tumor and Infection-induced inflammation: T+/I+ (poor), if both proinflam-status;T+/I- (T-only), if inflammation only due to tumor;T-/I+ (I-only), if inflammation only due to Covid;T-/I- (favorable), if no proinflam-status. The IF of circulating neutrophils by flow cytometry was determined in a unicenter prospective cohort (PC) of pts with cancer during Covid-19 infection and in healthy volunteers (HV). Primary endpoint was 30-day mortality. Results: 524 pts were enrolled in the RC with a median follow- up of 84d (95%CI 78-90). Median age was 69 (range 35-98), 52% were male and 78% had baseline PS <1.Thoracic cancers were the most common (26%). 70% had active disease, 51% advanced stage and 57% were under systemic therapy. dNLR was high in 25% at baseline vs 55% at Covid-19 diagnosis. The median dNLR increase between both timepoints was +70% (IQR: 0-349%);42% had +100% increase of dNLR. Pts distribution and mortality across FLARE groups is resumed in the Table. Overall mortality rate was 26%. In multivariate analysis, including gender, stage and PS, the FLARE poor group was independently associated with 30-day mortality [OR 5.27;1.37-20.3]. 44 pts were enrolled in the PC. Median circulating neutrophils were higher in pts with cancer (n=10, 56.7% [IQR: 39-78.4%]) vs HV (n=6, 35.8% [IQR: 25.6-21%]), and particularly higher in pts with cancer and severe Covid-19 infection (n=7, 88.6% [IQR: 80.9-94%] (p=0.003). A more comprehensive characterization of the IF of circulating neutrophils, including Lox1/CD62/CD64, will be presented at ASCO. Conclusions: The FLARE score, combining tumor and Covid-19-induced proinflam-status, can identify the population at higher risk for mortality. A better characterization of circulating neutrophils may help improve the prediction of Covid-19 outcomes in pts with cancer. (Table Presented).
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Objectives: The development of effective targeted therapy and drug-design approaches against the SARS-CoV-2 is a universal health priority. Therefore, it is important to assess possible therapeutic strategies against SARS-CoV-2 via its most interaction targets. The present study aimed to perform a systematic review on clinical and experimental investigations regarding SARS-COV-2 interaction targets for human cell entry. Methods: A systematic search using relevant MeSH terms and keywords was performed in PubMed, Scopus, Embase, and Web of Science (ISI) databases up to July 2021. Two reviewers independently assessed the eligibility of the studies, extracted the data, and evaluated the methodological quality of the included studies. Additionally, a narrative synthesis was done as a qualitative method for data gathering and synthesis of each outcome measure. Results: A total of 5610 studies were identified, and 128 articles were included in the systematic review. Based on the results, spike antigen was the only interaction protein from SARS-CoV-2. However, the interaction proteins from humans varied including different spike receptors and several cleavage enzymes. The most common interactions of the spike protein of SARS-CoV-2 for cell entry were ACE2 (entry receptor) and TMPRSS2 (for spike priming). A lot of published studies have mainly focused on the ACE2 receptor followed by the TMPRSS family and furin. Based on the results, ACE2 polymorphisms as well as spike RBD mutations affected the SARS-CoV-2 binding affinity. Conclusion: The included studies shed more light on SARS-CoV-2 cellular entry mechanisms and detailed interactions, which could enhance the understanding of SARS-CoV-2 pathogenesis and the development of new and comprehensive therapeutic approaches.
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Background: Platelet transfusions are an essential treatment for attenuating bleeding but are often ineffective in cases of intractable haemorrhage. Although anucleate, mature platelets synthesize protein de novo, making them amenable to mRNA gene therapy;however, there remains to be an effective transfection technique. Advancements in lipid nanoparticle technology has enabled leading COVID vaccines and is an efficient method to deliver nucleic acids into target cells. Recently, we developed a LNP approach to successfully express exogenous protein in platelets [unpublished data], a first step towards demonstrating that donor platelet coagulability can be engineered. However, the effects of LNP treatment on platelet function has yet to be investigated. Aims: To determine whether LNP-treated donor platelets are functionally similar, or better, in vitro, than platelets currently transfused clinically as a next step to establish LNP engineered platelets as a new cell therapy. Methods: The hemostatic profiles of LNP-treated and clinical donor platelets were assessed using an adapted rotational thromboelastometry model of dilutional coagulopathy. LNP-treated platelets were also stimulated with conventional platelet agonists to test if responsiveness is similar, or better than clinical platelets using flow cytometry. Results: LNP-treated platelets have a comparable hemostatic profile to clinically transfused platelets and significantly improved clotting dynamics when spiked into hemodiluted whole blood in an in vitro transfusion simulation. LNP-treated platelets also respond comparably, and in some cases more potently to agonist simulation compared to untreated platelets as indicated by similar p-selectin surface presentation. Summary/Conclusions: LNPs are an effective way to deliver exogenous nucleic acids into platelets;they do not significantly change platelet coagulability or responsiveness to agonists. LNP platelet engineering is a promising new approach to load platelets with procoagulant protein to enhance their function.
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Introduction: The main factors associated with disease severity in Covid-19 are age, sex, body weight, hypertension, and diabetes. Biomarkers of hemostatic activation have been shown to be independent predictors of disease severity in different populations. Aim: To evaluate whether biomarkers of hemostatic activation were associated with clinical outcomes in patients admitted to a field hospital set up to provide initial care to patients in the early symptomatic phase of Covid-19. Methods: Data and samples were obtained from June to September 2020. Laboratory evaluation included complete blood counts, PT, aPTT, fibrinogen, D-dimer, factor VIII activity, Von Willebrand Factor (VWF) (activity and antigen), C reactive protein (CRP) and P-selectin (ELISA). Patients were segregated by outcome, with clinical worsening defined as need for ICU, mechanical ventilation, pulmonary embolism, deep vein thrombosis or death. Results and discussion: In total 209 were enrolled in the study, of which 24 presented clinical deterioration (11.5%). In both groups there was more male patients. In the group of clinical worsening the mean age was 58.1 and improvement was 53.6 years old. Concerning smoking, 3.2% of patients that improved smoke. Regarding pulmonar infiltrate, it was verified in 50% in the group that worsening versus 41% in clinical improvement. No differences could be observed between patient subgroups regarding the presence of fever (63.2% vs. 62.5%), dry cough (75.1% vs. 87.5%) and dyspnea (65.9% vs. 54.2%) at admission. As main comorbidities, the groups presented chronic obstructive pulmonary disease (2.2% vs 8.3%), asthma (3.2% vs 4.2%), chronic heart failure (1.1% vs 8.3%), arterial hypertension (46% vs 41.7%) and diabetes (28.1% vs 33.3%) in comparing improved with clinical deterioration patients. In general, it was verified a significant decrease in platelet number (p = 0.0426), and an increase in the parameters of aPTT (0.0084), CRP (p = 0.0450), vWF antigen (p = 0.0022) and ristocetin cofactor (p = 0.0032). Conclusion: Our results demonstrate that hemostasis activation is associated with clinical deterioration even at the early phases of Covid-19. The Ethics Research Committee of the University of Campinas approved all of the experimental procedures, and all individuals signed the informed consent form.
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Background Sickle cell disease (SCD) is a hemoglobinopathy which manifests clinically as hemolytic anemia and recurrent episodes of pain caused by vaso-occlusion, among other symptoms. Vaso-occlusive crises (VOCs) account for an overwhelming majority of visits to the emergency room (ER) and hospitalizations for patients with SCD (Shah et al. PLoS One 2019). Upregulation of P-selectin, a cellular adhesion protein expressed on activated platelets and endothelial cells, contributes to the pathophysiology of VOCs. Crizanlizumab is a monoclonal antibody administered intravenously that inhibits the interaction of P-selectin with its ligand;it was approved by the Food and Drug Administration (FDA) as a treatment for SCD patients in 2019. In the Phase II SUSTAIN trial, crizanlizumab therapy resulted in a significantly lower rate of sickle cell-related pain crises than placebo (Ataga et al. N Engl J Med 2017). Due to their high-risk status for COVID-19, the pandemic has posed significant challenges for SCD patients to readily access healthcare, including novel therapies such as crizanlizumab. This study aimed to investigate the utility of telemedicine in facilitating access to crizanlizumab as well as compare acute medical care utilization for patients on crizanlizumab six months before initiating therapy and up to six months after their final dose in 2020. Methods All patients (≥18 years of age as of January 1, 2020) with SCD who received crizanlizumab between January 1, 2020 and December 31, 2020 at Rush University Medical Center (RUMC) were included in the final analysis. Demographic features as well as the type of visit when the patient and healthcare provider discussed crizanlizumab treatment was documented. Paired t-tests and Wilcoxon matched-pairs signed rank tests were utilized to compare acute medical care utilization - defined by the number of ER visits, urgent care visits, and hospitalizations - six months prior to initiating therapy and six months after completing the specified therapy regimen for 2020. Simple linear regression models and multiple regression models were conducted to control for sex, BMI, age, insurance, duration of treatment, and type of visit. Results A total of ten patients were included in the final analysis. Five (50%) patients first agreed to proceed with crizanlizumab therapy during a telehealth video visit with their provider, one (10%) made the decision during a telehealth phone visit, and the other four (40%) did so during a traditional office visit. 9 (90%) patients were still on crizanlizumab after June 1, 2020, the date that RUMC urgent care started seeing patients with SCD. The mean number of visits to the ER in the period before initiating therapy was 2.8 (SD=4.26) compared to 2.5 (SD=2.76) after last dose in 2020, however this finding did not achieve statistical significance (p>0.9999). Visits to the urgent care clinic, on average, increased significantly from 1.7 (SD=2.87) in the six months before initiating therapy to 8.2 (SD=11.02) in the six months after ending therapy for 2020 (p=0.0234). The mean number of hospitalizations in the period before initiating therapy was 6.6 (SD=5.19) compared to 4.6 (SD=3.44) in the period after last dose in 2020, however this was also not statistically significant (p=0.2309). None of the covariates had a significant effect on differences in acute care utilization in the period before and after therapy in 2020. Conclusion This study suggests that administration of crizanlizumab therapy did reduce hospitalization and ED visits, but the results could not achieve statistical significance due to our small sample size and short study duration. The number of urgent care visits for these patients, however, did differ significantly from the period before initiating therapy to the six months after the last dose in 2020. This finding can be attributed to the fact that due to the COVID-19 pandemic, urgent care services were made increasingly available to SCD patients beginning on June 1, 2020 to avoid admissions to the ER and hospital. Additionally, our study suggests that during the COVID-19 pandemic, telemedicine played an important role in providing health services to patients with SCD, and it could continue to improve care accessibility for SCD patients after the pandemic. Continued collection and analysis of real-world data is needed to further understand the effect of crizanlizumab therapy on utilization of acute medical care. [Formula presented] Disclosures: Jain: DOVA: Other: advisory board;Sanofi: Other: advisory board;Argenx: Other: advisory board;Novartis: Speakers Bureau;GBT: Speakers Bureau.
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Background: In some patients, SARS-CoV-2 infection induces cytokine storm, hypercoagulability and endothelial cell activation leading to worsening of COVID-19, intubation and death. Prompt identification of patients at risk of intubation or death is un unmet need. Objective: To derive a prognostic score for the risk of intubation or death in patients with critical COVID-19 by assessing biomarkers of hypercoagulability, endothelial cell activation and inflammation and a large panel of clinical analytes. Methods: We conducted a prospective, observational monocentric study enrolling 118 patients with COVID-19 admitted in the intensive care unit. At the 1st day of ICU admission all patients were assessed for the following biomarkers : protein C, protein S, antithrombin, D-Dimer, fibrin monomers, factors VIIa, V, XII, XII, VIII, von Willebrand antigen, fibrinogen, procoagulant phospholipid dependent clotting time, TFPI, thrombomodulin, P-selectin, heparinase, microparticles exposing tissue factor, IL-6, complement C3a, C5a, thrombin generation, prothrombin time, activated partial thromboplastin time, hemogram, platelet count) and clinical predictors. The clinical outcomes were intubation and mortality during hospitalization in ICU. Results: The intubation and mortality rate were 70 % and 18% respectively. Multivariate analysis led to the derivation of the COMPASS- COVID19-ICU score composed of P-Selectin, D-Dimer, free TFPI, TF activity, IL-6 and FXII, age and duration of hospitalization. The score predicted the risk of intubation or death with high sensitivity and specificity (0.90 and 0.92, respectively). Conclusions and Relevance: Critical COVID-19 is related with severe endothelial cell activation and hypercoagulability orchestrated in the context of inflammation. The COMPASS-COVID19-ICU score is an accurate predictive model for the evaluation of the risk of mechanical ventilation and death in patients with critical COVID-19. The assessment with the COMPASS- COVID-19-ICU score is feasible in tertiary hospitals. In this context it could be placed in the diagnostic procedure of personalized medical management and prompt therapeutic intervention. Disclosures: Terpos: Novartis: Honoraria;Janssen: Consultancy, Honoraria, Research Funding;Genesis: Consultancy, Honoraria, Research Funding;Celgene: Consultancy, Honoraria, Research Funding;BMS: Honoraria;Amgen: Consultancy, Honoraria, Research Funding;Takeda: Consultancy, Honoraria, Research Funding;Sanofi: Consultancy, Honoraria, Research Funding;GSK: Honoraria, Research Funding. Dimopoulos: Amgen: Honoraria;BMS: Honoraria;Takeda: Honoraria;Beigene: Honoraria;Janssen: Honoraria.
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Background: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a severe prothrombotic complication of adenoviral vaccines including ChAdOx1 nCoV-19 (AstraZeneca) vaccine. The putative mechanism involves formation of pathological anti-PF4 antibodies that activate platelets via the FcγRIIa receptor to drive thrombosis and the associated thrombocytopenia. Functional assays are important in the VITT diagnostic pathway as not all detectable PF4 antibodies are pathogenic. Detection of procoagulant platelets (platelets supporting thrombin generation) in presence of PF4 has been proposed as a diagnostic assay for VITT (Althaus et al). Procoagulant platelets are not typically generated in response to low level agonist stimulation;however, combination of ligand binding of G-protein coupled receptors (GPCR) (eg. PAR1) and ITAM linked receptors (eg. GPVI, CLEC2 and FcγRIIa) synergistically induce procoagulant platelet formation. Here, we describe an alternative flow cytometric assay to diagnose VITT. We hypothesized that priming of platelets with a PAR1 agonist at a level sufficient to release PF4, but insufficient to generate a significant procoagulant response in donor platelets, would provide a platform in which procoagulant response would be dependent on presence of FcγRIIa dependent procoagulant antibodies in patient plasma, without requirement for additional PF4. Methods: Our previously established flow cytometry-based procoagulant platelet assay (using cell death marker GSAO and P-selectin) was modified to incorporate exogenous patient plasma and performed on whole blood from healthy donors screened for FcγRIIa responsiveness (aggregation response to anti-CD9 antibody, ALB6), primed with 5 μM SFLLRN. The assay was performed on Australian patients referred for confirmatory VITT testing with probable VITT (confirmed thrombosis within 4-42 days of ChAdOx1 nCov-19 vaccination, D-Dimer > 5x ULN, platelets < 150 x 10 9/L or falling platelet count) after screening on PF4/heparin ELISA (Asserachrom HPIA IgG Assay, Stago Diagnostics). Procoagulant response was also measured in presence of 0.5 U/mL and 100 U/mL heparin, monoclonal FcγRIIa blocking antibody, IV.3, and intravenous immunoglobulin, IVIg. Some plasmas were incubated with ChAdOx1 nCoV-19 or SARS-CoV-2 spike protein. Flow cytometry positive patients were also tested by serotonin release assay (SRA) and multiplate aggregometry. Clinical correlation was obtained. Results: Citrated plasma from 49 unique patients with suspected VITT are reported. Plasma from ELISA+ve patients with clinical picture consistent with VITT (n=31), significantly increased the procoagulant platelet proportions in healthy donors in presence of 5 μM SFLLRN (p<0.0001, Figure 1A). This increase was not seen with plasma from healthy donors (n=14);or individuals exposed to ChAdOx1 nCov-19 vaccine without VITT: thrombocytopenic thrombosis patients who were ELISA-ve and SRA-ve (n=14);or low-level ELISA+ve patients without thrombocytopenia who were negative by either multiplate or SRA (n=4). The procoagulant platelet response induced by VITT positive plasma was reduced with low dose heparin (0.5 U/mL, p<0.01) except for 3 patients who showed a heparin-enhancing effect (Figure 1B). High dose heparin (100 U/mL, p<0.0001), IV.3 (10 µg/mL, p<0.0001) or IVIg (10 mg/mL, p<0.0001) abolished the procoagulant response (Figures 1C-D). The in vitro effect of IVIg was predictive of the in vivo response to IVIg therapy (Figure 1E). Addition of SARS-CoV-2 spike protein had no effect on the procoagulant platelet response. ChAdOx1 nCov-19 had an inconsistent effect on procoagulant platelet formation in presence of VITT plasma. Use of donors without a robust aggregation response to ALB6 resulted in false negative results. Conclusion: Induction of FcγRIIa dependent procoagulant response by patient plasma, suppressible by high dose heparin and IVIg, is highly indicative of VITT in the correct clinical circumstance. This assay modification of priming donor platelets from known FcγRIIa responsive donors ith a GPCR agonist to potentiate the ITAM signaling from platelet activating immune complexes, results in a sensitive and specific assay. This may represent a functional platform that can be adopted into diagnostic laboratories to identify patients with platelet-activating antibodies and potentially predict treatment responses. [Formula presented] Disclosures: No relevant conflicts of interest to declare.
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Background: the pathogenesis of severe COVID-19 involves the deregulated activation of different compartments of immunothrombosis, which are otherwise important for pathogen eradication and tissue repair. Coagulation activation, angiogenesis and alterations of endothelial barrier (EB) are elements of immunothrombosis that have been shown to be involved in the pathogenesis of COVID-19. Angiopoietins (Ang) 1 and 2 and their receptor Tie2 and VEGF-A are well-known pro-angiogenic mediators that, during inflammation also mediate EB disruption. Recently, it has also been demonstrated that the Ang/Tie2 pathway is involved in coagulation activation. Here we explored whether increased levels of angiogenesis/EB regulators (which have been previously associated with disease severity in COVID-19) are also associated with both EB disruption and coagulation activation in this condition. Methods: the study population consisted of 30 patients with COVID-19 confirmed by RT-PCR and presenting typical CT findings admitted due to hypoxemia. Thirty sex- and age-matched healthy individuals were recruited at the same time, from the same geographic region. Patients were part of a clinical trial (REBEC: U1111-1250-1843) but samples were obtained before any study intervention, within 24 hours from diagnosis confirmation. Circulating levels of angiogenesis/EB regulation mediators and coagulation biomarkers were measured by commercial assays (immunological or functional). Monolayers of endothelial cells from umbilical veins (HUVECs) or lung (HULECs) were used for measurement of EB integrity using an impedance sensor system (ECIS, Electric Cell-substrate Impedance Sensing System). Cells were stimulated with serum from patients or healthy individuals and EB integrity was continuously monitored for 36 hours. Clinical outcomes were obtained from the digital medical records. Results: mean length of hospital stay (LOS) was 12.9 ± 9.8 days. Twelve patients (40%) required intensive care (ICU) and 28/30 patients survived. Mean D-dimer was 3,609 ± 14,440 ng/mL. Circulating levels of Ang1, Ang2, sTie2 and VEGF-A were all significantly increased in patients compared to healthy individuals (Ang1: 463.2 ± 194.6 vs 237.4 ± 104.9 pg/mL, p<0.0001;Ang2: 1,926 (1,275 - 3,134) vs 1,215 (9 - 1,440 pg/mL), p<0.0001;Tie2: 10,753 ± 2,377 vs 8,603 ± 1,851 pg/mL, p<0.0001 and VEGF-A: 94.7 (73.4 - 116.0) vs 45.9 (39.7 - 57.0 pg/mL), p<0.0001.). In contrast, soluble VE-cadherin levels were decreased in patients compared to healthy individuals (1,234 ± 318 vs 1,539 ± 363 ng/mL, P=0.001). Serum from COVID-19 patients induced decreases of EB integrity in monolayers of both HUVECs and HULECs as early as 15 minutes, lasting up to 5 hours after stimulation (figure 1). The magnitude of EB disruption was correlated with clinically relevant outcomes such as time of ICU stay and LOS (figure 1). Interestingly, levels of Ang1, Ang2 and soluble VE-cadherin levels were also significantly correlated with the magnitude of EB disruption, as well as with biomarkers of coagulation activation such as fibrinogen, Von Willebrand Factor antigen levels, PAI-1, P-selectin and urokinase receptor (uPAR). Conclusions: Ang-1/Ang-2 mediated Tie2 signaling has been shown to be important for the fine regulation of barrier integrity and coagulation activation at the endothelial level, which are two critical elements of immunothrombosis. Our results provide evidence supporting that the interplay between these processes can play a role in the mechanisms driving COVID-19 severity, and suggest that targeting the Ang/Tie2 and VEGF-A pathways could be attractive strategies to modulate not only changes of the alveolar-capillary barrier, but also of coagulation activation in COVID-19. Figure 1. In (a), endothelial barrier (EB) integrity of HUVEC monolayers upon stimulation by serum from COVID-19 patients and healthy individuals (n=27-30 per group). The lower the normalized resistance, the higher the magnitude of EB disruption. Significant differences (* to ****) are evident from 15 min to 5 hours (An va corrected for multiple comparisons). In the lower panels, the correlation of EB disruption with clinically relevant outcomes such as length of hospital stay (b) and days of intensive care (c) are shown. Negative correlations (Spearman test) indicate that the magnitude of EB disruption is associated with worse outcomes. [Formula presented] Disclosures: No relevant conflicts of interest to declare.
ABSTRACT
Background: ChAdOx1 nCoV-19 (AstraZeneca) and Ad26.COV2.S (Janssen Johnson & Johnson) vaccines against COVID-19 have been associated with thrombotic thrombocytopenic reactions referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT) characterized by the presence of platelet-activating, anti-PF4 antibodies. While VITT shares key clinical features with a similar but separate entity, Heparin-induced thrombocytopenia (HIT), there appear to be important differences: 1) VITT patients have extremely high thrombosis rates and are very strongly positive in PF4-polyanion ELISAs, and 2) Many patients with VITT frequently present with refractoriness to therapy or have disease recurrence that suggests distinct antibody characteristics due to a strong autoimmune anti-PF4 response. Aims: The goal of this study was to characterize anti-PF4 antibodies in VITT. Methods: Five VITT patients were studied, one after ChAdOx1 nCoV-19 vaccination and four after Ad26.COV2. Reactivity of VITT anti-PF4 antibodies to uncomplexed PF4, PF4-Polyvinyl sulfonate (PVS), and PF4-heparin targets was evaluated, and the platelet-activating ability of these antibodies was examined in the PF4-dependent P-selectin Expression assay (PEA). Anti-PF4 antibodies were isolated from patient blood samples using PF4-treated heparin sepharose beads, and isolated antibodies were subject to mass spectrometric evaluation (Liquid Chromatography Electrospray Ionization Quadrupole time-of-flight mass spectrometry [LC-ESI-QTOF MS]). Results: Antibodies from all VITT patients recognized both uncomplexed and complexed PF4 (Fig. 1A). Interestingly, recognition of PF4 by VITT antibodies was lower if PF4 targets were complexed with polyanions, PVS, or heparin (Fig. 1A). These results contrasted with those obtained in a “classical” HIT patient which showed reactivity to PF4/polyanion complexes, but not to uncomplexed PF4 (Fig 1A). All samples activated platelets in the PEA (data not shown). Mass spectrometric evaluation of anti-PF4 antibodies isolated from VITT patients demonstrated monoclonal anti-PF4 antibodies in three patients, and bi- and tri-clonal antibodies in one patient each (a representative monoclonal antibody anti-PF4 antibody is shown in Fig 1B). Consistent with current dogma, polyclonal anti-PF4/polyanion antibodies were seen in “classical” HIT (Fig 1C). Evaluation of anti-PF4 antibodies in spontaneous HIT, a type of autoimmune HIT seen in pro-inflammatory milieus such as orthopedic surgery and infectious prodromes also demonstrated monoclonal anti-PF4 antibodies (Fig 1D). Eluates from control heparin-sepharose beads did not reveal any immunoglobulins (data not shown). Conclusion: Although development of platelet-activating anti-PF4 antibodies and the thrombotic thrombocytopenia syndrome seen after ChAdOx1 nCoV-19 and Ad26.COV2.S vaccination resembles HIT, these findings demonstrate that clonally restricted anti-PF4 antibodies mediate VITT while polyclonal anti-PF4 antibodies mediate HIT. In addition, we noted clonally-restricted anti-PF4 antibodies in another condition that does not require proximate heparin exposure, spontaneous (“autoimmune”) HIT. In VITT, the strong immune response after vaccine administration may result in the activation of a single or few pre-existing anti-PF4 reactive clones, and development of clonally restricted anti-PF4 antibodies with a similar pathophysiology to Spontaneous HIT. It is also likely that high levels of monoclonal/oligoclonal anti-PF4 antibodies cause the severe thrombotic phenotypes seen in VITT and Spontaneous HIT. The high mortality rate and reports of disease refractoriness to therapy in VITT may warrant consideration of additional therapeutic modalities like rituximab and therapeutic plasma exchange in select cases. Figure Legends: (A): VITT (Patient 1-ChAdOx1 nCoV-19;Patients 2-5, Ad26.COV2.S) patient samples were tested in ELISA against uncomplexed PF4 (white), and PF4 in complex with polyvinyl sulfonate (light grey), or unfractionated heparin (dark gray). (B-D) Mass spectrometric evalua ion of anti-PF4 antibodies isolated from VITT (B), HIT (C) and spontaneous HIT patient sera (D). “Relative Intensity” refers to abundance of the Ig light chain relative to the polyclonal background. Numbers above Ig light chain peaks depict mass/charge ratios. NC- Normal control. [Formula presented] Disclosures: Murray: Mayo Clinic: Other: Has received patents for the Mass-Fix technology which has been licensed to the Binding Site with potential royalties. Padmanabhan: Veralox Therapeutics: Membership on an entity's Board of Directors or advisory committees.
ABSTRACT
Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause severe vascular complications associated with endothelial dysfunction and systemic inflammation. COVID19-specific IgG are detectable within a week of infection. Long COVID-19 has been described in patients continuing to exhibit symptoms after the virus is no longer detectable in the respiratory secretions, including fatigue, dyspnea, headache, and brain fog. The recent FAIR Health study reviewed a total of 1,959,982 COVID-19 patients for the prevalence of long COVID symptoms and reported that 23.2% had at least one post-COVID symptom [1]. The underlying biologic mechanisms of long COVID remain unclear, thus treatments are limited to symptomatic relief and supportive care. Many long COVID symptoms are consistent with systemic inflammation and impaired oxygen delivery observed in individuals with sickle cell disease (SCD), in turn associated with elevated blood cell adhesion and decreased red blood cell (RBC) stability. The aim of this study was to determine if deleterious changes in in blood cell properties related to adhesion and membrane stability under stress can be associated with the symptoms of long COVID-19. In this work we evaluated 7 SCD patients that were diagnosed with SARS-Cov-2 and tracked their recovery using semiquantitative IgG and blood cell function assays. Methods: Blood samples were collected by the Foundation for Sickle Cell Disease (SCD) Research from SCD (homozygous SS, n=6) patients coming for regular or urgent clinic visit with SARS-CoV-2 serological and blood cell functions tests performed per the standard of care. Semiquantitative IgG assay was performed using DXi-80 (Beckman Coulter). Flow adhesion of whole blood to VCAM-1 (FA-WB-VCAM)and P-Selectin (FA-WB-Psel) substrates were determined by counting the cells that remain adherent in a microfluidics channel after perfusion with whole blood 1:1 diluted with HBSS buffer and washed by reversed flow at 1 dyne/cm 2. Red blood cell mechanical fragility (RBC MF) was measured as hemolysis induced by an oscillating cylindrical magnet with periodic non-invasive probing of cell-free hemoglobin fraction. Six individuals with SCD recovering from SARS-Cov-2 with biomarker data available both before and for more than 3 months after the infection (179±62 days) were included in the study. Results: IgG levels varied from less than 0.1 to 37, with positive values being defined as IgG > 1. The median estimated half-life of IgG decline was 53 days ranging from 25 to 90 days (the last, for the hospitalized patient). Averaged for IgG positive (IgG+) and IgG negative (IgG-) conditions, combining pre- and post-infection IgG- conditions, values of patient hemoglobin (Hb), FA-WB-VCAM, FA-WB-Psel, and RBC MF cell properties lacked statistical significance (under both a paired t-test and population statistics). Hb levels remained essentially unchanged regardless of the time from infection or IgG status. However, FA-WB-VCAM, FA-WB-Psel, and RBC MF were all significantly elevated after SARS-Cov-2 seroconversion and remained elevated despite declining IgG levels (e.g., Fig. 1). These increases in biomarker values were statistically significant for both FA-WB-VCAM and RBC MF, and were approaching significance for FA-WB-Psel (p<0065). These increases were highly patient-specific with potential return to pe-infection values observed in some cases at about 5-6 months after the infection. A qualitative review of the medical records indicated a new subjective report of fatigue in 5 of 6 patients. Longer observations are required to determine if abnormal blood cell adhesive properties and RBC membrane instability are mechanisms of long-COVID-19 pathophysiology. Conclusions: Whole blood adhesion to both p-selectin and VCAM-1 as well as RBC membrane stability can be significantly impaired in convalescent SARS-Cov-2 patients suggesting an association with long COVID-19. New and emerging treatments that modify whole blood adhesive properties and RBC membrane stability should be investigated for t eir potential to accelerated recovery from long COVID-19. Health F. A Detailed Study of Patients with Long-Haul COVID: An Analysis of Private Healthcare Claims;White Paper. June 15, 2021 Disclosures: Tarasev: Functional Fluidics: Current holder of stock options in a privately-held company. Ferranti: Functional Fluidics: Current holder of stock options in a privately-held company. Allen: Functional Fluidics: Current Employment. Gao: Functional Fluidics: Current Employment. Topping: Functional Fluidics: Current Employment. Ferranti: Functional Fluidics: Current Employment. Makinde-Odesola: Functional Fluidics: Other: conduct research for academic program. Hines: Functional Fluidics: Current holder of stock options in a privately-held company.
ABSTRACT
Background: The coronavirus disease 2019 (COVID-19) has spread around the world with high cardiovascular complications and mortality. Patients with heart pathology and diabetes mellitus were at greatest risk. An accurate and timely laboratory diagnosis is a vital step to help manage cardiovascular disease during this pandemic. Purpose: To conduct a prospective analysis of complete blood count parameters, inflammatory response, endothelial dysfunction of arterial wall and hemostasis in groups of patients undergoing COVID-19 associated pneumonia with and without type 2 diabetes mellitus (DM2);to highlight indicators of long-term adverse cardiovascular events. Methods: The study was carried out within register on one-year cardiac follow-up of patients after COVID-19-associated pneumonia. Patients (n=380) were identified in the period from April to July 2020 according to the data of medical information system of monoinfectious hospital. At the moment, data of the first 65 patients with cardiovascular pathology are obtained. Group 1 included 53 patients without DM2 (mean age 47.83±15.86 years), group 2 consisted of 12 patients with DM2 (61.71±9.12 years). Baseline parameters of complete blood count, biochemistry and hemostasis were assessed on the day of hospitalization. In-depth analysis of laboratory parameters was carried out in 3 months. Results: In group 1 significant decrease of coagulogram parameters: INR (p=0.004), fibrinogen, APTT, thrombocrit, large platelets level (p<0.0001), CRP level, liver enzymes (p<0.0001), leukocytes (p=0.015), erythrocytes (p=0.006) and increase in hematocrit (p<0.0001) were registered in 3 months compared to baseline data. In group 2 positive dynamics of CRP (p=0.018), platelets (p=0046), APTT (p=0.043) and erythrocytes (p=0.028) were revealed, while CRP concentration remained higher than reference values in 3 months. In group 2 in-depth analysis of biomarkers revealed values exceeding normal levels: hs-CRP (4.72±3.33 mg/L), homocysteine (13.17±7.95 μmol/L), myeloperoxidase (47.6±38.51), NT-proBNP (154.56±127.30 mg/ml), P-selectin (141.29±124.71) TgFb1 (6549.86±1987.87 pg/ml). Correlation analysis detected positive association of homocysteine level with platelets level (p=0.002. R=0.998), myeloperoxidase with fibrinogen (p=0.012. R=0.865). Conclusion: Three months after COVID-19 elevated levels of inflammatory markers (CRP, hs-CRP, homocysteine), endothelial dysfunction and thrombophilia (large platelets, P-selectin, TgFb1) are indicators of prolonged arterial inflammatory syndrome and increased predisposition to coagulopathy with thrombosis determining a very high risk of developing adverse cardiovascular events in patients with DM2.
ABSTRACT
Background: Septic shock generates an important inflammatory reaction, endothelial activation and a procoagulant state leading to microvascular thrombosis and subsequent organ impairment [1]. Similarly, a severe inflammatory reaction and a coagulopathy with pulmonary micro-thrombosis eventually leading to acute lung injury, is a typical feature of critical form of Coronavirus disease 2019 (Covid-19) [2]. Our aim was to compare coagulation, platelet activation and plateletsneutrophils interplay between control, septic shock and critical Covid-19 patients. Methods/Materials: A total of 118 patients were included in our prospective, monocentric, observational study between February 2019 and June 2020. Septic shock (n=48) and Covid-19 (n=22) patients were consecutively included at admission in our ICU department. Control patients (n=48) with matched gender and co-morbidities were recruited at central lab consultation. Results: Septic shock patients had worse severity scores due to multiple organ failure (assessed by APACHE II and SOFA score) whereas Covid-19 patients had more severe respiratory failure and a longer ICU length-ofstay (Table 1). At the time of inclusion, CRP and lymphocyte count were comparable between septic shock and Covid-19 patients. White cell count ad neutrophil count was higher for septic shock patients. Analysis of coagulation showed a prolonged INR, TT and aPTT in septic shock although only INR was prolonged in Covid-19. Thrombin antithrombin complex (TATc) formation was similar in both pathologies, whereas consumption of antithrombin III (ATIII) and D-dimers formation was more pronounced in septic shock. Platelet count was lower in septic shock and platelet activation, assessed via plasmatic levels of soluble P-selectin (sCD62P) and Trem-like transcript 1 (sTLT-1), was more important in septic shock. Neutrophil activation and NETosis, evaluated by levels of circulating myeloperoxidase (MPO) and citrullinated histone 3 (H3-Cit), was similarly increased in both groups (Figure 1). Conclusions: This study confirmed an activation of coagulation cascade, platelet activation and NETosis in both septic shock and critical Covid-19, compared with control patients. Importantly, the extent of these changes was similar or less pronounced in critical COVID-19 compared with septic shock.