COVID-19 plasma exosomes promote proinflammatory immune responses in peripheral blood mononuclear cells.

Elevated serum cytokine production in COVID-19 patients is associated with disease progression and severity. However, the stimuli that initiate cytokine production in patients remain to be fully revealed. Virus-infected cells release virus-associated exosomes, extracellular vesicles of endocytic origin, into the blood to deliver viral cargoes able to regulate immune responses. Here, we report that plasma exosomes of COVID-19 patients contain SARS-CoV-2 double stranded RNA (dsRNA) and stimulate robust production of interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), and other inflammatory cytokines and chemokines by human peripheral mononuclear cells. Exosome depletion abolished these stimulated responses. COVID-19 plasma exosomes induced proinflammatory responses in CD4+ T cells, CD8+ T cells, and CD14+ monocytes but not significantly in regulatory T cells, Th17 T cells, or central memory T cells. COVID-19 plasma exosomes protect the SARS-CoV-2 dsRNA cargo from RNase and deliver the dsRNA into recipient cells. These exosomes significantly increase expression of endosomal toll-like receptor 3 (TLR3), TLR7, TLR8, and TLR9 in peripheral T cells and monocytes. A pharmacological inhibitor of TLR3 considerably reduced cytokine and chemokine production by CD4+ and CD8+ T cells but not by CD14+ monocytes, highlighting divergent signaling pathways of immune cells in response to COVID-19 plasma exosomes. Our results identify a novel model of intercellular crosstalk following SARS-CoV-2 infection that evoke immune responses positioned to contribute to elevated cytokine production associated with COVID-19 progression, severity, and long-haul symptoms.

An efficient deep neural network framework for COVID-19 lung infection segmentation.

Since the outbreak of Coronavirus Disease 2019 (COVID-19) in 2020, it has significantly affected the global health system. The use of deep learning technology to automatically segment pneumonia lesions from Computed Tomography (CT) images can greatly reduce the workload of physicians and expand traditional diagnostic methods. However, there are still some challenges to tackle the task, including obtaining high-quality annotations and subtle differences between classes. In the present study, a novel deep neural network based on Resnet architecture is proposed to automatically segment infected areas from CT images. To reduce the annotation cost, a Vector Quantized Variational AutoEncoder (VQ-VAE) branch is added to reconstruct the input images for purpose of regularizing the shared decoder and the latent maps of the VQ-VAE are utilized to further improve the feature representation. Moreover, a novel proportions loss is presented for mitigating class imbalance and enhance the generalization ability of the model. In addition, a semi-supervised mechanism based on adversarial learning to the network has been proposed, which can utilize the information of the trusted region in unlabeled images to further regularize the network. Extensive experiments on the COVID-SemiSeg are performed to verify the superiority of the proposed method, and the results are in line with expectations.

Breakthrough SARS-CoV-2 Infection Outcomes in Vaccinated Patients with Chronic Liver Disease and Cirrhosis: A National COVID Cohort Collaborative Study (preprint)

Background and AimsThe incidence and outcomes of breakthrough SARS-CoV-2 infections in vaccinated chronic liver disease (CLD) patients have not been well-characterized in non-veteran populations. We used the National COVID Cohort Collaborative (N3C), a dataset of 10.7 million patients, of whom 0.9 million have vaccination data, to describe outcomes in vaccinated CLD patients. MethodsWe identified all CLD patients with or without cirrhosis regardless of vaccination status who had SARS-CoV-2 testing in the N3C Data Enclave as of 1/15/2022. We used Poisson regression to estimate incidence rates of breakthrough infections and Cox survival analyses to associate vaccination status with all-cause mortality at 30 days among infected CLD patients. ResultsWe isolated 278,457 total CLD patients: 43,079 (15%) vaccinated and 235,378 (85%) unvaccinated. Of the 43,079 vaccinated CLD patients, 32,838 (76%) were without cirrhosis and 10,441 (24%) were with cirrhosis. Estimated incidence rates for breakthrough infections were 5.6 and 5.1 per 1,000 person-months for 27,235 fully vaccinated CLD patients without cirrhosis and for 8,218 fully vaccinated CLD patients with cirrhosis, respectively. Of the 68,048 unvaccinated and 10,441 vaccinated CLD patients with cirrhosis in our cohort, 15% and 3.7%, respectively, developed SARS-CoV-2 infection. The combined 30-day all-cause rate of mechanical ventilation (without death) or death after SARS-CoV-2 infection for unvaccinated and vaccinated CLD patients with cirrhosis were 15.2% and 7.7%, respectively. Compared to unvaccinated patients with cirrhosis, full vaccination was associated with a 0.34-times adjusted hazard of death at 30 days. ConclusionsIn this N3C Data Enclave study, breakthrough infection rates were similar amongst CLD patients with and without cirrhosis. Full vaccination was associated with a 66% reduction in risk of all-cause mortality among CLD patients with cirrhosis after infection. These results provide an additional impetus for increasing vaccination uptake among patients with severe liver disease.

Viral mimetic poly(I:C) induces neutrophil extracellular traps via PAD4 to promote inflammation and thrombosis.

Neutrophil extracellular traps (NETs) are extracellular webs of DNA, histones and granular contents that are released by neutrophils to control infections. However, NETs that is not properly regulated can propagate inflammation and thrombosis. It was recognized that viruses can induce NETs. As a synthetic analog of viral double-stranded (ds) RNA, polyinosinic-polycytidylic acid [poly(I:C)] is known to induce inflammation and thrombosis. However, whether and how poly(I:C) modulates NETs remains unclear. Here, we have demonstrated that poly(I:C) induced extracellular DNA traps in human neutrophils in a dose-dependent manner. Further, poly(I:C) or dsRNA virus elevated the levels of myeloperoxidase-DNA complexes and citrullinated histone H3, which are specific markers of NETs, in both neutrophil supernatants and mouse plasma. Interestingly, a potent peptidylarginine deiminase 4 (PAD4) inhibitor, BB-CL-Amidine (BB-CLA) or PAD4 knockdown effectively prevented poly(I:C)-induced NETs formation and release. In addition, BB-CLA abrogated poly(I:C)-triggered neutrophil activation and infiltration, and vascular permeability in lungs. BB-CLA also attenuated poly(I:C)-induced thrombocytopenia in circulation, fibrin deposition and thrombus formation in tissues. Taken together, these results suggest that viral mimetic poly(I:C) may induce NETs-dependent inflammation and thrombosis through PAD4, and that inhibiting PAD4 may become a good strategy to protect against viral infection-caused inflammation/thrombosis-related pathological conditions of diseases.

Outcomes of SARS-CoV-2 Infection in Patients with Chronic Liver Disease and Cirrhosis: a N3C Study (preprint)

Background and AimsIn patients with chronic liver diseases (CLD) with or without cirrhosis, existing data on the risk of adverse outcomes with SARS-CoV-2 infection have been mixed or have limited generalizability. We used the National COVID Cohort Collaborative (N3C) Data Enclave, a harmonized electronic health record (EHR) dataset of 5.9 million nationally-representative, diverse, and gender-balanced patients, to describe outcomes in patients with CLD and cirrhosis with SARS-CoV-2. MethodsWe identified all chronic liver diseases patients with and without cirrhosis who had SARS-CoV-2 testing documented in the N3C Data Enclave as of data release date 5/15/2021. The primary outcome was 30-day all-cause mortality. Survival analysis methods were used to estimate cumulative incidences of death, hospitalization, and mechanical ventilation, and to calculate the associations of SARS-CoV-2 infection, presence of cirrhosis, and demographic and clinical factors to 30-day mortality. ResultsWe isolated 217,143 patients with CLD: 129,097 (59%) without cirrhosis and SARS-CoV-2 negative, 25,844 (12%) without cirrhosis and SARS-CoV-2 positive, 54,065 (25%) with cirrhosis and SARS-CoV-2 negative, and 8,137 (4%) with cirrhosis and SARS-CoV-2 positive. Among CLD patients without cirrhosis, 30-day all-cause mortality rates were 0.4% in SARS-CoV-2 negative patients and 1.8% in positive patients. Among CLD patients with cirrhosis, 30-day all-cause mortality rates were 4.0% in SARS-CoV-2 negative patients and 9.7% in positive patients. Compared to those who tested SARS-CoV-2 negative, SARS-CoV-2 positivity was associated with more than two-fold (aHR 2.43, 95% CI 2.23-2.64) hazard of death at 30 days among patients with cirrhosis. Compared to patients without cirrhosis, the presence of cirrhosis was associated with a three-fold (aHR 3.39, 95% CI 2.96-3.89) hazard of death at 30 days among patients who tested SARS-CoV-2 positive. Age (aHR 1.03 per year, 95% CI 1.03-1.04) was associated with death at 30 days among patients with cirrhosis who were SARS-CoV-2 positive. ConclusionsIn this study of nearly 220,000 CLD patients, we found SARS-CoV-2 infection in patients with cirrhosis was associated with 2.43-times mortality hazard, and the presence of cirrhosis among CLD patients infected with SARS-CoV-2 were associated with 3.39-times mortality hazard. Compared to previous studies, our use of a nationally-representative, diverse, and gender-balanced dataset enables wide generalizability of these findings.

Healthy neonate born to a SARS-CoV-2 infected woman: A case report and review of literature.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly discovered coronavirus that has generated a worldwide outbreak of infections. Many people with coronavirus disease-2019 (COVID-19) have developed severe illness, and a significant number have died. However, little is known regarding infection by the novel virus in pregnant women. We herein present a case of COVID-19 confirmed in a woman delivering a neonate who was negative for SARS-CoV-2 and related it to a review of the literature on pregnant women and human coronavirus infections. CASE SUMMARY: The patient was a 36-year-old pregnant woman in her third trimester who had developed progressive clinical symptoms when she was confirmed as infected with SARS-CoV-2. Given the potential risks for both the pregnant woman and the fetus, an emergency cesarean section was performed, and the baby and his mother were separately quarantined and cared for. As a result, the baby currently shows no signs of SARS-CoV-2 infection (his lower respiratory tract samples were negative for the virus), while the mother completely recovered from COVID-19. CONCLUSION: Although we presented a single case, the successful result is of great significance for pregnant women with SARS-CoV-2 infection and with respect to fully understanding novel coronavirus pneumonia.

Biochemical and antigenic characterization of the structural proteins and their post-translational modifications in purified SARS-CoV-2 virions of an inactivated vaccine candidate.

In the face of COVID-19 pandemic caused by the newly emerged SARS-CoV-2, an inactivated, Vero cell-based, whole virion vaccine candidate has been developed and entered into phase III clinical trials within six months. Biochemical and immunogenic characterization of structural proteins and their post-translational modifications in virions, the end-products of the vaccine candidate, would be essential for the quality control and process development of vaccine products and for studying the immunogenicity and pathogenesis of SARS-CoV-2. By using a panel of rabbit antisera against virions and five structural proteins together with a convalescent serum, the spike (S) glycoprotein was shown to be N-linked glycosylated, PNGase F-sensitive, endoglycosidase H-resistant and cleaved by Furin-like proteases into S1 and S2 subunits. The full-length S and S1/S2 subunits could form homodimers/trimers. The membrane (M) protein was partially N-linked glycosylated; the accessory protein 3a existed in three different forms, indicative of cleavage and dimerization. Furthermore, analysis of the antigenicity of these proteins and their post-translationally modified forms demonstrated that S protein induced the strongest antibody response in both convalescent and immunized animal sera. Interestingly, immunization with the inactivated vaccine did not elicit antibody response against the S2 subunit, whereas strong antibody response against both S1 and S2 subunits was detected in the convalescent serum. Moreover, vaccination stimulated stronger antibody response against S multimers than did the natural infection. This study revealed that the native S glycoprotein stimulated neutralizing antibodies, while bacterially-expressed S fragments did not. The study on S modifications would facilitate design of S-based anti-SARS-CoV-2 vaccines.

Guideline for diagnosis and treatment of spine trauma in the epidemic of COVID-19.

Outbreak of COVID-19 is ongoing all over the world. Spine trauma is one of the most common types of trauma and will probably be encountered during the fight against COVID-19 and resumption of work and production. Patients with unstable spine fractures or continuous deterioration of neurological function require emergency surgery. The COVID-19 epidemic has brought tremendous challenges to the diagnosis and treatment of such patients. To coordinate the diagnosis and treatment of infectious disease prevention and spine trauma so as to formulate a rigorous diagnosis and treatment plan and to reduce the disability and mortality of the disease, multidisciplinary collaboration is needed. This expert consensus is formulated in order to (1) prevent and control the epidemic, (2) diagnose and treat patients with spine trauma reasonably, and (3) reduce the risk of cross-infection between patients and medical personnel during the treatment.