Altered fibrin clot structure contributes to thrombosis risk in severe COVID-19

The high incidence of thrombotic events suggests a possible role of the contact system pathway in COVID-19 pathology. Here, we demonstrate altered levels of factor XII (FXII) and its activation products in two independent cohorts of critically ill COVID-19 patients in comparison to patients suffering from severe acute respiratory distress syndrome due to influenza virus (ARDS-influenza). Compatible with this data, we report rapid consumption of FXII in COVID-19, but not in ARDS-influenza, plasma. Interestingly, the kaolin clotting time was not prolonged in COVID-19 as compared to ARDS-influenza. Using confocal and electron microscopy, we show that increased FXII activation rate, in conjunction with elevated fibrinogen levels, triggers formation of fibrinolysis-resistant, compact clots with thin fibers and small pores in COVID-19. Accordingly, we observed clot lysis in 30% of COVID-19 patients and 84% of ARDS-influenza subjects. Analysis of lung tissue sections revealed wide-spread extra- and intra-vascular compact fibrin deposits in COVID-19. Together, our results indicate that elevated fibrinogen levels and increased FXII activation rate promote thrombosis and thrombolysis resistance via enhanced thrombus formation and stability in COVID-19.

Endothelial dysfunction determines severe COVID-19 in combination with dysregulated lymphocyte responses and cytokine networks

The systemic processes involved in the manifestation of life-threatening COVID-19 and in disease recovery are still incompletely understood, despite investigations focusing on the dysregulation of immune responses after SARS-CoV-2 infection. To define hallmarks of severe COVID-19 and disease recovery in convalescent patients, we combined analyses of immune cells and cytokine/chemokine networks with endothelial activation and injury. ICU patients displayed an altered immune signature with prolonged lymphopenia but expansion of granulocytes and plasmablasts along with activated and terminally differentiated T and NK cells and high levels of SARS-CoV-2-specific antibodies. Core signature of seven plasma proteins revealed a highly inflammatory microenvironment in addition to endothelial injury in severe COVID-19. Changes within this signature were associated with either disease progression or recovery. In summary, our data suggest that besides a strong inflammatory response, severe COVID-19 is driven by endothelial activation and barrier disruption, whereby recovery depends on the regeneration of the endothelial integrity.

Scent dog identification of SARS-CoV-2 infections, similar across different body fluids

BackgroundThe main strategy to contain the current SARS-CoV-2 pandemic remains to implement a comprehensive testing, tracing and quarantining strategy until vaccination of the population is adequate. MethodsTen dogs were trained to detect SARS-CoV-2 infections in beta-propiolactone inactivated saliva samples. The subsequent cognitive transfer performance for the recognition of non-inactivated samples were tested on saliva, urine, and sweat in a randomised, double-blind controlled study. ResultsDogs were tested on a total of 5242 randomised sample presentations. Dogs detected non-inactivated saliva samples with a diagnostic sensitivity of 84% and specificity of 95%. In a subsequent experiment to compare the scent recognition between the three non-inactivated body fluids, diagnostic sensitivity and specificity were 95% and 98% for urine, 91% and 94% for sweat, 82%, and 96% for saliva respectively. ConclusionsThe scent cognitive transfer performance between inactivated and non-inactivated samples as well as between different sample materials indicates that global, specific SARS-CoV-2-associated volatile compounds are released across different body secretions, independently from the patients symptoms. FundingThe project was funded as a special research project of the German Armed Forces. The funding source DZIF-Fasttrack 1.921 provided us with means for biosampling.

Changes in utilization and outcomes of mechanical ventilation of COVID-19 during the course of the pandemic in Germany in 2020: an observational study of 7,490 patients

RationaleThe role of non-invasive ventilation (NIV) in severe COVID-19 remains a matter of debate. ObjectivesTo determine the utilization and outcome of NIV in COVID-19 in an unbiased cohort. MethodsObservational study of confirmed COVID-19 cases of claims data of the Local Health Care Funds comparing patients with non-invasive and invasive mechanical ventilation (IMV) between spring versus autumn period 2020. Measurements and Main ResultsNationwide cohort of 7490 cases (median/IQR age 70/60-79 years, 66% male) 3851 (51%) patients primarily received IMV without NIV, 1614 (22%) patients received NIV without subsequent intubation, and 1247 (17%) patients had NIV failure (NIV-F), defined by subsequent endotracheal intubation. The proportion of patients who received invasive MV decreased from 74% to 39% during the second period. Accordingly, the proportion of patients with NIV exclusively increased from 10% to 28%, and those failing NIV increased from 9% to 21%. Median length of hospital stay decreased from 26 to 22 days, and duration of MV decreased from 11.6 to 7.6 days. The NIV failure rate decreased from 49% to 42%. Overall mortality remained unchanged (51% versus 53%). Mortality was 39% with NIV-only, 52% with IMV and 66% with NIV-F with mortality rates steadily increasing from 58% in early NIV-F (day 1) to 75% in late NIV-F (>4 days). ConclusionUtilization of NIV rapidly increased during the autumn period, which was associated with a reduced duration of MV, but not with overall mortality. High NIV-F rates are associated with increased mortality, particularly in late NIV-F. FundingInstitutional support and physical resources were provided by the University Witten/Herdecke and Kliniken der Stadt Koln and the Federal Association of the Local Health Care Funds. At a Glance CommentaryO_ST_ABSScientific Knowledge on the SubjectC_ST_ABSCurrent management of ventilatory support in COVID-19 patients with respiratory failure is heterogeneous. Despite increasing use of non-invasive ventilation (NIV), defining intubation criteria still remains a matter of uncertainty and discussion, especially with regard to the balance between the NIV benefits and the risk of NIV failure. In addition, robust data concerning the influence of the duration and failure of NIV on intubation and mortality rates are still missing, although the time span between initiation of NIV and subsequent intubation in case of respiratory failure progression is suggested to influence patient outcome. What This Study Adds to the FieldThis is the first large observational study describing differences of ventilatory strategies between the spring and autumn period of the SARS-CoV-2 pandemic in Germany and provides the in-hospital mortality rate of 7,490 patients who received mechanical ventilation. The increased utilization of NIV from 10% (first period) to 29% (second period) was associated with overall reduced durations of mechanical ventilation and length of hospital stay, but overall mortality remained comparably high and reached 51%, 53% respectively. Patients succeeding with NIV had lower mortality rates than those getting intubated without preceding NIV attempts, but those failing NIV had higher mortality rates, respectively, and this became even more predominant in late NIV failure. The present observational study shows the increasing role of NIV in the concert of ICU medicine related to COVID-19, but also clearly addresses its risks in addition to its benefits, both impacting on mortality.

Current evidence for COVID-19 therapies: a systematic literature review

Effective therapeutic interventions for the treatment and prevention of COVID-19 are urgently needed. A systematic review was conducted to identify clinical trials of pharmacological interventions for COVID-19 published between 1 December 2019 and 14 October 2020. Data regarding efficacy of interventions, in terms of mortality, hospitalisation and need for ventilation, were extracted from identified studies and synthesised qualitatively. In total, 42 clinical trials were included. Interventions assessed included antiviral, mucolytic, anti-malarial, anti-inflammatory and immunomodulatory therapies. Some reductions in mortality, hospitalisation and need for ventilation were seen with interferons and remdesivir, particularly when administered early, and with the mucolytic drug, bromhexine. Most studies of lopinavir/ritonavir and hydroxychloroquine did not show significant efficacy over standard care/placebo. Dexamethasone significantly reduced mortality, hospitalisation and need for ventilation versus standard care, particularly in patients with severe disease. Evidence for other classes of interventions was limited. Many trials had a moderate-to-high risk of bias, particularly in terms of blinding; most were short-term; and some included low patient numbers. This review highlights the need for well-designed clinical trials of therapeutic interventions for COVID-19 to increase the quality of available evidence. It also emphasises the importance of tailoring interventions to disease stage and severity for maximum efficacy.

Reappearance of Effector T Cells Predicts Successful Recovery from COVID-19

BackgroundElucidating the role of T cell responses in COVID-19 is of utmost importance to understand the clearance of SARS-CoV-2 infection. Methods30 hospitalized COVID-19 patients and 60 age- and gender-matched healthy controls (HC) participated in this study. We used two comprehensive 11-color flow cytometric panels conforming to Good Laboratory Practice and approved for clinical diagnostics. FindingsAbsolute numbers of lymphocyte subsets were differentially decreased in COVID-19 patients according to clinical severity. In severe disease (SD) patients, all lymphocyte subsets were reduced, whilst in mild disease (MD) NK, NKT and {gamma}{delta} T cells were at the level of HC. Additionally, we provide evidence of T cell activation in MD but not SD, when compared to HC. Follow up samples revealed a marked increase in effector T cells and memory subsets in convalescing but not in non-convalescing patients. InterpretationOur data suggest that activation and expansion of innate and adaptive lymphocytes play a major role in COVID-19. Additionally, recovery is associated with formation of T cell memory as suggested by the missing formation of effector and central memory T cells in SD but not in MD. Understanding T cell-responses in the context of clinical severity might serve as foundation to overcome the lack of effective anti-viral immune response in severely affected COVID-19 patients and can offer prognostic value as biomarker for disease outcome and control. FundingFunded by German Research Foundation, Excellence Strategy - EXC 2155 "RESIST"-Project ID39087428, and DFG-SFB900/3-Project ID158989968, grants SFB900-B3 to R.F., SFB900-B8 to I P. and C.K.

Home spirometry as early detector of azithromycin refractory bronchiolitis obliterans syndrome in lung transplant recipients.

BACKGROUND: To evaluate the utility of home spirometry (HS) versus office spirometry (OS) in assessing treatment response to azithromycin in bronchiolitis obliterans syndrome (BOS). METHODS: 239 Lung transplant recipients were retrospectively studied. ΔFEV1 ± 10% from FEV1 at azithromycin initiation for ≥7 consecutive days in HS or ≥2 measures in OS were taken as cut-off for response or progression. RESULTS: Based upon HS, 161/239 (67%) patients were progressive despite macrolide, 19 of who exhibited transient improvement in FEV1 (11%). Time to progression was 29 (13-96) days earlier with HS than in OS. Forty-six (19%) recipients responded in HS after median 81 (22-343) days, whilst 22% remained stable. Concordance in azithromycin treatment response between OS and HS was observed in 210 of 239 patients (88%). Response or stabilization conferred significant improvement in survival (p = 0.005). Transient azithromycin responders demonstrated improved survival when compared to azithromycin refractory patients (p = 0.034). CONCLUSIONS: HS identified azithromycin refractory patients significantly earlier than OS, possibly facilitating aggressive treatment escalation that may improve long-term outcome. Treatment response to azithromycin should be assessed 4 weeks after initiation. Responders demonstrated best survival, with even transient response conferring benefit. Macrolide-refractory BOS carried the worst prognosis.

Augmentation therapy with alpha1-antitrypsin: novel perspectives.

SERPINA1, α-antitrypsin (AAT) is an acute phase protein, a member of the serpin (serine protease inhibitor) super family and one of the most abundant protease inhibitors in the circulation. The clinical importance of AAT is emphasized in persons with inherited AAT deficiency who exhibit high risk of developing early onset pulmonary emphysema, neonatal hepatitis, liver cirrhosis, which may appear at any age, and in rare cases panniculitis and vasculitis. The most common and severe AAT deficiency is associated with the Z (Glu342 to Lys) mutation. It is also well established that Z AAT deficiency results from the polymerization and accumulation of the misfolded AAT protein. Consequently, low levels of circulating Z AAT are assumed to be inadequate to neutralize elastolytic activity and to prevent lung tissue damage. Novel studies, however, are expanding the link between AAT and human diseases. Associations are shown between reduced AAT levels and HIV type 1 infection, hepatitis C infection, diabetes mellitus, vasculitis, panniculitis and other diseases. Given the importance of the protease/antiprotease imbalance in causing emphysema, augmentation of circulating AAT is used as a specific therapy for patients with AAT deficiency-related emphysema but not for those with liver diseases. According to the novel findings, therapy with AAT possesses antiinflammatory and immuno-modulatory effects across a broad spectrum of experimental models of systemic and local inflammation. Hence, in this article we will discuss putative new directions for the clinical use of therapy with AAT.