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Frontiers in Immunology 2020To ultimately combat the emerging COVID-19 pandemic, it is desired to develop an effective and safe vaccine against this highly contagious disease caused by the...
To ultimately combat the emerging COVID-19 pandemic, it is desired to develop an effective and safe vaccine against this highly contagious disease caused by the SARS-CoV-2 coronavirus. Our literature and clinical trial survey showed that the whole virus, as well as the spike (S) protein, nucleocapsid (N) protein, and membrane (M) protein, have been tested for vaccine development against SARS and MERS. However, these vaccine candidates might lack the induction of complete protection and have safety concerns. We then applied the Vaxign and the newly developed machine learning-based Vaxign-ML reverse vaccinology tools to predict COVID-19 vaccine candidates. Our Vaxign analysis found that the SARS-CoV-2 N protein sequence is conserved with SARS-CoV and MERS-CoV but not from the other four human coronaviruses causing mild symptoms. By investigating the entire proteome of SARS-CoV-2, six proteins, including the S protein and five non-structural proteins (nsp3, 3CL-pro, and nsp8-10), were predicted to be adhesins, which are crucial to the viral adhering and host invasion. The S, nsp3, and nsp8 proteins were also predicted by Vaxign-ML to induce high protective antigenicity. Besides the commonly used S protein, the nsp3 protein has not been tested in any coronavirus vaccine studies and was selected for further investigation. The nsp3 was found to be more conserved among SARS-CoV-2, SARS-CoV, and MERS-CoV than among 15 coronaviruses infecting human and other animals. The protein was also predicted to contain promiscuous MHC-I and MHC-II T-cell epitopes, and the predicted linear B-cell epitopes were found to be localized on the surface of the protein. Our predicted vaccine targets have the potential for effective and safe COVID-19 vaccine development. We also propose that an "Sp/Nsp cocktail vaccine" containing a structural protein(s) (Sp) and a non-structural protein(s) (Nsp) would stimulate effective complementary immune responses.
Topics: Animals; Betacoronavirus; COVID-19; COVID-19 Vaccines; Coronavirus Infections; Epitopes, B-Lymphocyte; Humans; Immunogenicity, Vaccine; Machine Learning; Middle East Respiratory Syndrome Coronavirus; Pandemics; Pneumonia, Viral; SARS-CoV-2; Viral Proteins; Viral Vaccines
PubMed: 32719684
DOI: 10.3389/fimmu.2020.01581 -
Cureus Apr 2020Cerebral venous sinus thrombosis (CVST) is a rare condition characterized by elevated intracranial pressure due to impaired cerebral venous drainage, potentially... (Review)
Review
Cerebral venous sinus thrombosis (CVST) is a rare condition characterized by elevated intracranial pressure due to impaired cerebral venous drainage, potentially leading to life-threatening consequences. We searched the PubMed electronic database for 'cerebral venous sinus thrombosis' and 'prothrombotic' cases reported in adults (19+ years) and conducted a systematic review for the published literature in the English language pooled with a case from our institution. Data were analyzed regarding patient demographics, risk factors, clinical features, treatment modalities, and outcomes when available. Thirty cases of CVST were identified (29 case reports, of whom two were described in a case series, and the one case from our institution). The patients' mean age was 39 years (range: 19 - 65). The male: female ratio was 1.14:1. The majority (73.3%) had at least one preexisting risk factor, with prescription drug use being the most common risk factor (33.3%) shared among all patients. Most patients (83.3%) presented with at least two symptoms. The most common presenting symptoms were headache (70%), gastrointestinal disturbance (50%), and seizures (40%). Focal deficits (36.7%), vision disturbances (30%), and altered consciousness (20%) were the remaining presenting complaints. Twelve cases (40%) commented on papilledema, with 10 (83.3%) having papilledema present. Anticoagulation abnormalities were examined in 26 cases (86.7%), out of which four cases (15.4%) had isolated protein S (PS) deficiency, three cases (11.5%) had isolated antithrombin III (ATIII) deficiency, and one case (3.8%) had isolated protein C (PC) deficiency. The most common initial imaging modality (22 cases, 73.3%), and most commonly used overall (23 cases, 76.7%), was computed tomography (CT). Magnetic resonance imaging (MRI) was the second most common imaging modality for initial use (five cases, 16.7%), diagnosis or confirmation of CVST (eight cases, 26.7%), and overall (21 cases, 70%). Heparin treatment was involved in the treatment of 18 cases (60%), and warfarin treatment was used in 10 cases (33.3%). Heparin-warfarin combination treatment was utilized in eight cases (26.7%). Most patients survived (28 cases, 93.3%), while the two remaining patients died secondary to brain death from the CVST (6.7%). The findings from this study highlight the clinical characteristics of CVST. Therefore, this study aims to increase awareness of this rare entity. Physicians should maintain a high index of suspicion in order to diagnose patients presenting in the proper clinical context, given this case shares various forms of presentations with other common clinical conditions but requires long-term anticoagulation.
PubMed: 32411555
DOI: 10.7759/cureus.7654 -
Journal of the American Heart... Oct 2019Background Inherited thrombophilias are well-established predisposing factors for venous thromboembolism, but their role in arterial thrombosis, such as arterial... (Meta-Analysis)
Meta-Analysis
Background Inherited thrombophilias are well-established predisposing factors for venous thromboembolism, but their role in arterial thrombosis, such as arterial ischemic stroke, remains uncertain. We aimed to evaluate the association between inherited thrombophilia (factor V Leiden, prothrombin G20210A mutation, protein C deficiency, protein S deficiency, and antithrombin deficiency) and risk of arterial ischemic stroke in adults. Methods and Results We searched PubMed, EMBASE, and Cochrane Library Databases from inception to December 31, 2018. We included case-control or cohort studies of adults reporting the prevalence of inherited thrombophilias in those with arterial ischemic stroke and subjects without arterial ischemic stroke. Two reviewers (T.C., E.D.) independently searched the literature and extracted data. Pooled odds ratios (ORs) and 95% CIs were calculated using random-effects model. We identified 68 eligible studies, which collectively enrolled 11 916 stroke patients and 96 057 controls. The number of studies reporting factor V Leiden, prothrombin G20210A mutation, protein C deficiency, protein S deficiency, and antithrombin deficiency were 56, 45, 15, 17, and 12, respectively. Compared with controls, patients with arterial ischemic stroke were significantly more likely to have the following inherited thrombophilias: factor V Leiden (OR, 1.25; 95% CI, 1.08-1.44; I=0%), prothrombin G20210A mutation (OR, 1.48; 95% CI, 1.22-1.80; I=0%), protein C deficiency (OR, 2.13; 95% CI, 1.16-3.90; I=0%), and protein S deficiency (OR, 2.26; 95% CI, 1.34-3.80; I=8.8%). Statistical significance was not reached for antithrombin deficiency (OR, 1.25; 95% CI, 0.58-2.67; I=8.8%). Conclusions Inherited thrombophilias (factor V Leiden, prothrombin G20210A mutation, protein C deficiency, and protein S deficiency) are associated with an increased risk of arterial ischemic stroke in adults. The implications of these findings with respect to clinical management of patients with ischemic stroke require further investigation.
Topics: Adult; Aged; Blood Coagulation; Blood Coagulation Disorders, Inherited; Brain Ischemia; Female; Genetic Predisposition to Disease; Humans; Male; Middle Aged; Phenotype; Prognosis; Risk Assessment; Risk Factors; Stroke; Thrombophilia
PubMed: 31549567
DOI: 10.1161/JAHA.119.012877 -
Thrombosis Research Mar 2018Despite high rates of venous thromboembolism (VTE) among patients with hematologic malignancies, few tools exist to assist providers in identifying those patients at... (Review)
Review
INTRODUCTION
Despite high rates of venous thromboembolism (VTE) among patients with hematologic malignancies, few tools exist to assist providers in identifying those patients at highest risk for this potentially fatal complication. Laboratory biomarkers, such as d-dimer, have demonstrated utility in some clinical settings to distinguish patients at increased risk.
MATERIALS AND METHODS
We performed a systematic review of the literature utilizing search terms including "biomarker", "venous thromboembolism", "hematologic malignancy", "lymphoma", "myeloma" and "leukemia" in the Medline database. A total of 25 studies investigating laboratory biomarkers of increased thrombotic risk in the setting of hematologic malignancy were identified and included in this review.
RESULTS AND CONCLUSIONS
The most studied biomarkers, d-dimer and fibrinogen, demonstrated some degree of efficacy in identifying high-risk patients at levels >4.0 mg/L or <1.0 g/L respectively. Additional markers which demonstrated promise included thrombin generation, mean platelet volume, soluble VEGF, soluble P-selectin and extracellular vesicles. Other biomarkers reviewed, which did not consistently demonstrate significant associations with VTE included prothrombin fragments F1 + 2, factor VIII, protein C, protein S, von Willebrand antigen and activity, antithrombin, thrombin antithrombin complex, antiphospholopid antibody, plasminogen activator inhibitor, tissue factor pathway inhibitor and several variants associated with known hypercoagulable states (factor V Leiden, prothrombin gene variant, methylenetetrahydrofolate reductase variant). Data to support any of the biomarkers discussed here in routine clinical decision-making are currently lacking, but additional investigation in clinical studies, ideally in combination with clinical factors known to be associated with increased thrombotic risk, is warranted.
Topics: Biomarkers; Female; Hematologic Neoplasms; Humans; Male; Risk Factors; Venous Thromboembolism
PubMed: 29407626
DOI: 10.1016/j.thromres.2018.01.037 -
BMJ (Clinical Research Ed.) Oct 2017To provide evidence to support updated guidelines for the management of pregnant women with hereditary thrombophilia in order to reduce the risk of a first venous... (Meta-Analysis)
Meta-Analysis Review
To provide evidence to support updated guidelines for the management of pregnant women with hereditary thrombophilia in order to reduce the risk of a first venous thromboembolism (VTE) in pregnancy. Systematic review and bayesian meta-analysis. Embase, Medline, Web of Science, Cochrane Library, and Google Scholar from inception through 14 November 2016. Observational studies that reported on pregnancies without the use of anticoagulants and the outcome of first VTE for women with thrombophilia were eligible for inclusion. VTE was considered established if it was confirmed by objective means, or when the patient had received a full course of a full dose anticoagulant treatment without objective testing. 36 studies were included in the meta-analysis. All thrombophilias increased the risk for pregnancy associated VTE (probabilities ≥91%). Regarding absolute risks of pregnancy associated VTE, high risk thrombophilias were antithrombin deficiency (antepartum: 7.3%, 95% credible interval 1.8% to 15.6%; post partum: 11.1%, 3.7% to 21.0%), protein C deficiency (antepartum: 3.2%, 0.6% to 8.2%; post partum: 5.4%, 0.9% to 13.8%), protein S deficiency (antepartum: 0.9%, 0.0% to 3.7%; post partum: 4.2%; 0.7% to 9.4%), and homozygous factor V Leiden (antepartum: 2.8%, 0.0% to 8.6%; post partum: 2.8%, 0.0% to 8.8%). Absolute combined antepartum and postpartum risks for women with heterozygous factor V Leiden, heterozygous prothrombin G20210A mutations, or compound heterozygous factor V Leiden and prothrombin G20210A mutations were all below 3%. Women with antithrombin, protein C, or protein S deficiency or with homozygous factor V Leiden should be considered for antepartum or postpartum thrombosis prophylaxis, or both. Women with heterozygous factor V Leiden, heterozygous prothrombin G20210A mutation, or compound heterozygous factor V Leiden and prothrombin G20210A mutation should generally not be prescribed thrombosis prophylaxis on the basis of thrombophilia and family history alone. These data should be considered in future guidelines on pregnancy associated VTE risk.
Topics: Bayes Theorem; Evidence-Based Medicine; Female; Humans; Practice Guidelines as Topic; Pregnancy; Pregnancy Complications, Hematologic; Risk Factors; Thrombolytic Therapy; Thrombophilia; Venous Thrombosis
PubMed: 29074563
DOI: 10.1136/bmj.j4452 -
The American Journal of Clinical... Jun 2017: Considerable attention has recently focused on dietary protein's role in the mature skeleton, prompted partly by an interest in nonpharmacologic approaches to maintain... (Meta-Analysis)
Meta-Analysis Review
: Considerable attention has recently focused on dietary protein's role in the mature skeleton, prompted partly by an interest in nonpharmacologic approaches to maintain skeletal health in adult life. The aim was to conduct a systematic review and meta-analysis evaluating the effects of dietary protein intake alone and with calcium with or without vitamin D (Ca±D) on bone health measures in adults. Searches across 5 databases were conducted through October 2016 including randomized controlled trials (RCTs) and prospective cohort studies examining ) the effects of "high versus low" protein intake or ) dietary protein's synergistic effect with Ca±D intake on bone health outcomes. Two investigators independently conducted abstract and full-text screenings, data extractions, and risk of bias (ROB) assessments. Strength of evidence was rated by group consensus. Random-effects meta-analyses for outcomes with ≥4 RCTs were performed. Sixteen RCTs and 20 prospective cohort studies were included in the systematic review. Overall ROB was medium. Moderate evidence suggested that higher protein intake may have a protective effect on lumbar spine (LS) bone mineral density (BMD) compared with lower protein intake (net percentage change: 0.52%; 95% CI: 0.06%, 0.97%, : 0%; = 5) but no effect on total hip (TH), femoral neck (FN), or total body BMD or bone biomarkers. Limited evidence did not support an effect of protein with Ca±D on LS BMD, TH BMD, or forearm fractures; there was insufficient evidence for FN BMD and overall fractures. Current evidence shows no adverse effects of higher protein intakes. Although there were positive trends on BMD at most bone sites, only the LS showed moderate evidence to support benefits of higher protein intake. Studies were heterogeneous, and confounding could not be excluded. High-quality, long-term studies are needed to clarify dietary protein's role in bone health. This trial was registered at www.crd.york.ac.uk as CRD42015017751.
Topics: Bone Density; Bone Density Conservation Agents; Calcium; Calcium, Dietary; Dietary Proteins; Female; Fractures, Bone; Humans; Lumbar Vertebrae; Male; Osteoporosis; Vitamin D
PubMed: 28404575
DOI: 10.3945/ajcn.116.145110 -
Thrombosis and Haemostasis Jun 2017Data on paediatric pulmonary embolism (PE) are scarce. We sought to systematically review the current literature on childhood PE and conducted a search on paediatric PE... (Review)
Review
Data on paediatric pulmonary embolism (PE) are scarce. We sought to systematically review the current literature on childhood PE and conducted a search on paediatric PE via PubMed (1946-2013) and Embase (1980-2013). There was significant heterogeneity in reported data. Two patterns were noted: classic thromboembolic PE (TE-PE) and in situ pulmonary artery thrombosis (ISPAT). Mean age of presentation for TE-PE was 14.86 years, and 51 % of cases were males. The commonest method for diagnosis of TE-PE was contrast CT with angiography (74 % of patients). The diagnosis of TE-PE was often delayed. Although 85 % of children with TE-PE had an elevated D-dimer at presentation, it was non-discriminatory for the diagnosis. In paediatric TE-PE, the prevalence of central venous catheters was 23 %, immobilisation 38 %, systemic infection 31 % and obesity 13 %, elevated Factor VIII or von Willebrand factor levels 27 %, Protein C deficiency 17 %, Factor V Leiden 14 % and Protein S deficiency 7 %. In patients with TE-PE, pharmacologic thrombolysis was used in 29 %; unfractionated heparin was the most common initial anticoagulant treatment in 64 % and low-molecular-weight heparins the most common follow-up treatment in 83 %. Duration of anticoagulant therapy was variable and death was reported in 26 % of TE-PE patients. In contrast to TE-PE, patients with ISPAT were not investigated systematically for presence of thrombophilia, had more surgical interventions as the initial management and were often treated with anti-platelet medications. This review summarises important data and identifies gaps in the knowledge of paediatric PE, which may help to design future studies.
Topics: Adolescent; Angiography; Anticoagulants; Comorbidity; Female; Heparin; Humans; Male; Pneumoradiography; Prevalence; Pulmonary Artery; Pulmonary Embolism; Survival Analysis; Thromboembolism; Thrombosis
PubMed: 28331932
DOI: 10.1160/TH16-07-0529 -
Revue Neurologique Apr 2017High altitude may be a factor associated with cerebral venous thrombosis (CVT). As our knowledge of CVT at high altitude is limited, it was decided to pool such... (Review)
Review
BACKGROUND AND OBJECTIVE
High altitude may be a factor associated with cerebral venous thrombosis (CVT). As our knowledge of CVT at high altitude is limited, it was decided to pool such information from the available case studies to determine whether high altitude can predispose to CVT.
METHODS
A systematic review of the literature was performed for cases reporting CVT at high altitude. Searches of the PubMed database (up to July 2016) were performed for publications, using 'cerebral venous thrombosis' and 'high altitude' as keywords. Cross-referencing was also done to complete the search.
RESULTS
Ultimately, 13 articles were included in our systematic review. The population consisted of 17 patients, predominately male (14/17), with a mean age of 32 (range: 19-47) years. Altitude range was 3000-8200m. Nine patients stayed at high altitude for>2 weeks; the duration of high altitude stay was unknown for the remainder. A hypercoagulable state was found in nine patients: secondary polycythemia in five; protein C deficiency in one; protein S deficiency in one; and factor V Leiden mutations in two. No comorbidities were found in any of these patients.
CONCLUSION
Long-term stays at high altitude in association with a hypercoagulable state - in particular, congenital or acquired thrombophilia - appears to predispose to CVT. The association of CVT with a single exposure to high altitude seems low, but the risk cannot as yet be specifically estimated.
Topics: Adult; Altitude; Blood Coagulation Disorders; Female; Humans; Intracranial Thrombosis; Male; Middle Aged; Neuroimaging; Venous Thrombosis; Young Adult
PubMed: 28038774
DOI: 10.1016/j.neurol.2016.11.004 -
The Cochrane Database of Systematic... Nov 2016Among pediatric patients, newborns are at highest risk of developing thromboembolism. Neonatal thromboembolic (TE) events may consist of both venous and arterial... (Review)
Review
BACKGROUND
Among pediatric patients, newborns are at highest risk of developing thromboembolism. Neonatal thromboembolic (TE) events may consist of both venous and arterial thromboses and often iatrogenic complications (eg, central catheterization). Treatment guidelines for pediatric patients with TE events most often are extrapolated from the literature regarding adults. Options for the management of neonatal TE events include expectant management; nitroglycerin ointment; thrombolytic therapy or anticoagulant therapy, or a combination of the two; and surgery. Since the 1990s, low molecular weight heparin (LMWH) has become the neonatal anticoagulant of choice. Reasons for its appeal include predictable dose response, no need for venous access, and limited monitoring requirements. The overall major complication rate is around 5%. Whether preterm infants are at increased risk is unclear. No data are available on the frequency of osteoporosis, heparin-induced thrombocytopenia (HIT), or other hypersensitivity reactions in children and neonates exposed to LMWH.
OBJECTIVES
To assess whether heparin treatment (both unfractionated heparin [UFH] and LMWH) reduces mortality and morbidity rates in preterm and term newborn infants with diagnosed thrombosis. The intervention is compared with placebo or no treatment. Also, to assess the safety of heparin therapy (both UFH and LMWH) for potential harms.Subgroup analyses were planned to examine gestational age, birth weight, mode of thrombus diagnosis, presence of a central line, positive family history for genetic disorders (thrombophilia, deficiency of protein S and protein C, methylenetetrahydrofolate reductase [MTHFR] mutation), route of heparin administration, type of heparin used, and location of thrombus (see "Subgroup analysis and investigation of heterogeneity").
SEARCH METHODS
We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 4), MEDLINE via PubMed (1966 to May 9, 2016), Embase (1980 to May 9, 2016), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to May 9, 2016). We searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.
SELECTION CRITERIA
Randomized, quasi-randomized, and cluster-randomized controlled trials comparing heparin versus placebo or no treatment in preterm and term neonates with a diagnosis of thrombosis.
DATA COLLECTION AND ANALYSIS
We used the standard methods of the Cochrane Neonatal Review Group. Two review authors independently assessed studies identified by the search strategy for inclusion.
MAIN RESULTS
Our search strategy yielded 1160 references. Two review authors independently assessed all references for inclusion. We found no completed studies and no ongoing trials for inclusion.
AUTHORS' CONCLUSIONS
We found no studies that met our inclusion criteria and no evidence from randomized controlled trials to recommend or refute the use of heparin for treatment of neonates with thrombosis.
Topics: Anticoagulants; Heparin; Heparin, Low-Molecular-Weight; Humans; Infant, Newborn; Thrombosis
PubMed: 27820879
DOI: 10.1002/14651858.CD012185.pub2 -
Journal of Thrombosis and Haemostasis :... Jul 2016Essentials We performed a meta-analysis on thrombosis risk in thrombophilic oral contraceptive (COC)-users. The results support discouraging COC-use in women with a... (Meta-Analysis)
Meta-Analysis Review
UNLABELLED
Essentials We performed a meta-analysis on thrombosis risk in thrombophilic oral contraceptive (COC)-users. The results support discouraging COC-use in women with a natural anticoagulant deficiency. Contrary, additive risk of factor V Leiden (FVL) or prothrombin-G20210A (PT) mutation is modest. Women with a FVL/PT-mutation as single risk factor can use COCs if alternatives are not tolerated.
SUMMARY
Background Combined oral contraceptives (COCs) are associated with an increased risk of venous thromboembolism (VTE), which is shown to be more pronounced in women with hereditary thrombophilia. Currently, WHO recommendations state that COC-use in women with hereditary thrombophilias (antithrombin deficiency, protein C deficiency, protein S deficiency, factor V Leiden and prothrombin-G20210A mutation) is associated with an unacceptable health risk. Objective To perform a meta-analysis evaluating the additional risk of VTE in COC-users with thrombophilia. Methods The MEDLINE and EMBASE databases were searched on 10 February 2015 for potential eligible studies. A distinction was made between 'mild' (factor V Leiden and prothrombin-G20210A mutation) and 'severe' thrombophilia (antithrombin deficiency, protein C deficiency, protein S deficiency, double heterozygosity or homozygosity of factor V Leiden and prothrombin-G20210A mutation). Results We identified 12 case-control and three cohort studies. In COC-users, mild and severe thrombophilia increased the risk of VTE almost 6-fold (rate ratio [RR], 5.89; 95% confidence interval [CI], 4.21-8.23) and 7-fold (RR, 7.15; 95% CI, 2.93-17.45), respectively. The cohort studies showed that absolute VTE risk was far higher in COC-users with severe thrombophilia than in those with mild thrombophilia (4.3 to 4.6 vs. 0.49 to 2.0 per 100 pill-years, respectively), and these differences in absolute risks were also noted in non-affected women (0.48 to 0.7 vs. 0.19 to 0.0), but with the caveat that absolute risks were estimated in relatives of thrombophilic patients with VTE (i.e. with a positive family history). Conclusion These results support discouraging COC-use in women with severe hereditary thrombophilia. By contrast, additive VTE risk of mild thrombophilia is modest. When no other risk factors are present, (e.g. family history) COCs can be offered to these women when reliable alternative contraceptives are not tolerated.
Topics: Adolescent; Adult; Aged; Anticoagulants; Case-Control Studies; Cohort Studies; Contraceptives, Oral, Combined; Factor V; Female; Heterozygote; Humans; Middle Aged; Mutation; Protein C Deficiency; Protein S Deficiency; Prothrombin; Risk Factors; Thrombophilia; Venous Thromboembolism; Young Adult
PubMed: 27121914
DOI: 10.1111/jth.13349