Myxovirus Resistance Protein A Research Articles

Biomarkers of viral and bacterial infection in rhinovirus pneumonia.

Rhinovirus (RV) is often detected in children hospitalized with pneumonia, but the role of RV in causing pneumonia is still unclear. White blood cell count, C-reactive protein, procalcitonin, and myxovirus resistance protein A (MxA) levels were determined from blood samples in children (n = 24) hospitalized with radiologically verified pneumonia. Respiratory viruses were identified from nasal swabs by using reverse transcription polymerase chain reaction assays. Among RV-positive children, the cycle threshold value, RV subtyping by sequence analysis, and the clearance of RV by weekly nasal swabs were determined. RV-positive children with pneumonia were compared to other virus-positive children with pneumonia, and to children (n = 13) with RV-positive upper respiratory tract infection from a separate earlier study. RV was detected in 6 children and other viruses in 10 children with pneumonia (viral co-detections excluded). All RV-positive children with pneumonia had high white blood cell counts, plasma C-reactive protein or procalcitonin levels, or alveolar changes in chest radiograph strongly indicating bacterial infection. The median cycle threshold value for RV was low (23.2) indicating a high RV load, and a rapid clearance of RV was observed in all. Blood level of viral biomarker MxA was lower among RV-positive children with pneumonia (median 100 μg/L) than among other virus-positive children with pneumonia (median 495 μg/L, p = 0.034) or children with RV-positive upper respiratory tract infection (median 620 μg/L, p = 0.011). Our observations suggest a true viral-bacterial coinfection in RV-positive pneumonia. Low MxA levels in RV-associated pneumonia need further studies.

The relationship between a previous infectious disease caused by influenza, herpes simplex, or Epstein-Barr viruses as the biological threatening agents with recurrent episodes of multiple sclerosis

"Although multiple sclerosis (MS) is the most common neurological disease of young adults, afflicting hundreds of thousands of people worldwide, its pathogenesis is still only incompletely understood. There seems to be substantial heterogeneity in disease mechanisms, but in the majority of cases an autoimmune origin or at least a decisive autoimmune component is postulated. Therefore, pathogenic research focuses on different players programmed by the immune system. In this study, biomarkers such as Human myxovirus resistance protein A (MxA), Anti-EBNA antibody and Interleukin S10-12- 17 have been tested. Study of hypotheses show that: Interleukin levels in the blood of MS patients in the experimental group (patients with recurrence) is higher than controls (patients without recurrence condition). The level of anti-EBNA antibody in MS patients in other groups (patients with recurrent) and control group (patients without recurrence condition) is high. The level of the human myxovirus resistance protein A (MxA) in patients with multiple sclerosis in the experimental group (patients with recurrence) is less than the control group (patients without recurrence condition). The level of anti-EBNA antibody in MS patients in other groups (patients with recurrent) and control group (patients without recurrence condition) is high."

Increased Polymerase Activity of Zoonotic H7N9 Allows Partial Escape from MxA.

The interferon-induced myxovirus resistance protein A (MxA) is a potent restriction factor that prevents zoonotic infection from influenza A virus (IAV) subtype H7N9. Individuals expressing antivirally inactive MxA variants are highly susceptible to these infections. However, human-adapted IAVs have acquired specific mutations in the viral nucleoprotein (NP) that allow escape from MxA-mediated restriction but that have not been observed in MxA-sensitive, human H7N9 isolates. To date, it is unknown whether H7N9 can adapt to escape MxA-mediated restriction. To study this, we infected Rag2-knockout (Rag2-/-) mice with a defect in T and B cell maturation carrying a human MxA transgene (MxAtg/-Rag2-/-). In these mice, the virus could replicate for several weeks facilitating host adaptation. In MxAtg/-Rag2-/-, but not in Rag2-/- mice, the well-described mammalian adaptation E627K in the viral polymerase subunit PB2 was acquired, but no variants with MxA escape mutations in NP were detected. Utilizing reverse genetics, we could show that acquisition of PB2 E627K allowed partial evasion from MxA restriction in MxAtg/tg mice. However, pretreatment with type I interferon decreased viral replication in these mice, suggesting that PB2 E627K is not a true MxA escape mutation. Based on these results, we speculate that it might be difficult for H7N9 to acquire MxA escape mutations in the viral NP. This is consistent with previous findings showing that MxA escape mutations cause severe attenuation of IAVs of avian origin.

Diagnostic Accuracy of a Bacterial and Viral Biomarker Point-of-Care Test in the Outpatient Setting

Acute respiratory infections (ARIs) account for most outpatient visits. Discriminating bacterial vs viral etiology is a diagnostic challenge with therapeutic implications. To investigate whether FebriDx, a rapid, point-of-care immunoassay, can differentiate bacterial- from viral-associated host immune response in ARI through measurement of myxovirus resistance protein A (MxA) and C-reactive protein (CRP) from finger-stick blood. This diagnostic study enrolled adults and children who were symptomatic for ARI and individuals in a control group who were asymptomatic between October 2019 and April 2021. Included participants were a convenience sample of patients in outpatient settings (ie, emergency department, urgent care, and primary care) who were symptomatic, aged 1 year or older, and had suspected ARI and fever within 72 hours. Individuals with immunocompromised state and recent vaccine, antibiotics, stroke, surgery, major burn, or myocardial infarction were excluded. Of 1685 individuals assessed for eligibility, 259 individuals declined participation, 718 individuals were excluded, and 708 individuals were enrolled (520 patients with ARI, 170 patients without ARI, and 18 individuals who dropped out). Bacterial and viral immunoassay testing was performed using finger-stick blood. Results were read at 10 minutes, and treating clinicians and adjudicators were blinded to results. Bacterial- or viral-associated systemic host response to an ARI as determined by a predefined comparator algorithm with adjudication classified infection etiology. Among 520 participants with ARI (230 male patients [44.2%] and 290 female patients [55.8%]; mean [SD] age, 35.3 [17.7] years), 24 participants with missing laboratory information were classified as unknown (4.6%). Among 496 participants with a final diagnosis, 73 individuals (14.7%) were classified as having a bacterial-associated response, 296 individuals (59.7%) as having a viral-associated response, and 127 individuals (25.6%) as negative by the reference standard. The bacterial and viral test correctly classified 68 of 73 bacterial infections, demonstrating a sensitivity of 93.2% (95% CI, 84.9%-97.0%), specificity of 374 of 423 participants (88.4% [95% CI, 85.0%-91.1%]), positive predictive value (PPV) of 68 of 117 participants (58.1% [95% CI, 49.1%-66.7%), and negative predictive value (NPV) of 374 of 379 participants (98.7% [95% CI, 96.9%-99.4%]).The test correctly classified 208 of 296 viral infections, for a sensitivity of 70.3% (95% CI, 64.8%-75.2%), a specificity of 176 of 200 participants (88.0% [95% CI, 82.8%-91.8%]), a PPV of 208 of 232 participants (89.7% [95% CI, 85.1%-92.9%]), and an NPV of 176 of 264 participants (66.7% [95% CI, 60.8%-72.1%]). In this study, a rapid diagnostic test demonstrated diagnostic performance that may inform clinicians when assessing for bacterial or viral etiology of ARI symptoms.

Association of human myxovirus resistance protein A with severity of COVID-19

BackgroundIn this retrospective cohort study, we explored the correlation of blood human myxovirus resistance protein A (MxA) level with severity of disease in hospitalized COVID-19 patients.MethodsAll 304 patients admitted for COVID-19 in our hospital until 30th of April 2021 were included in this study. MxA was measured from peripheral blood samples in 268 cases. Patients were divided into groups based on their level of MxA on admission. We studied baseline characteristics and severity of disease on admission based on clinical parameters and inflammatory biomarker levels in each group. Severity of disease during hospitalization was determined by the applied level of respiratory support, by the usage of corticosteroids and by the duration of hospitalization.ResultsHigher MxA levels on admission were associated with a shorter duration of symptoms before admission, and with more severe disease. Adjusted Odds Ratios for any respiratory support were 9.92 (95%CI 2.11–46.58; p = 0.004) in patients with MxA between 400 μg/L and 799 μg/L (p = 0.004) and 20.08 (95%CI 4.51–89.44; p < 0.001) in patients with MxA ≥ 800 μg/L in comparison with patients with initial MxA < 400 μg/L. The usage of corticosteroids was significantly higher in the high-MxA group (77%) in comparison with the intermediate-MxA group (62%, p = 0.013) and low-MxA group (47%, p < 0.001).ConclusionsHigher initial levels of MxA were associated with more severe COVID-19. MxA may be a helpful additional biomarker to predict the severity of the disease.

Detection of group A streptococcus in children with confirmed viral pharyngitis and antiviral host response

Our aim was to study the detection of group A streptococcus (GAS) with different diagnostic methods in paediatric pharyngitis patients with and without a confirmed viral infection. In this prospective observational study, throat swabs and blood samples were collected from children (age 1–16 years) presenting to the emergency department with febrile pharyngitis. A confirmed viral infection was defined as a positive virus diagnostic test (nucleic acid amplification test [NAAT] and/or serology) together with an antiviral immune response of the host demonstrated by elevated (≥ 175 µg/L) myxovirus resistance protein A (MxA) blood concentration. Testing for GAS was performed by a throat culture, by 2 rapid antigen detection tests (StrepTop and mariPOC) and by 2 NAATs (Simplexa and Illumigene). Altogether, 83 children were recruited of whom 48 had samples available for GAS testing. Confirmed viral infection was diagnosed in 30/48 (63%) children with febrile pharyngitis. Enteroviruses 11/30 (37%), adenoviruses 9/30 (30%) and rhinoviruses 9/30 (30%) were the most common viruses detected. GAS was detected by throat culture in 5/30 (17%) with and in 6/18 (33%) patients without a confirmed viral infection. Respectively, GAS was detected in 4/30 (13%) and 6/18 (33%) by StrepTop, 13/30 (43%) and 10/18 (56%) by mariPOC, 6/30 (20%) and 9/18 (50%) by Simplexa, and 5/30 (17%) and 6/18 (30%) patients by Illumigene.Conclusion: GAS was frequently detected also in paediatric pharyngitis patients with a confirmed viral infection. The presence of antiviral host response and increased GAS detection by sensitive methods suggest incidental throat carriage of GAS in viral pharyngitis.What is Known:•The frequency and significance of GAS-virus co-detection are poorly characterised in children with pharyngitis.•Detection of a virus and the antiviral host response likely indicates symptomatic infection.What is New:•Group A streptococcus (GAS) was detected in 17–43% of the children with confirmed viral pharyngitis depending on the GAS diagnostic method.•Our results emphasize the risk of detecting and treating incidental pharyngeal carriage of GAS in children with viral pharyngitis.

The association between blood MxA mRNA and long-term disease activity in early multiple sclerosis.

BackgroundMyxovirus resistance protein A (MxA) is a protein that is upregulated by interferon-beta. Homeostatic MxA mRNA levels are potentially correlated with inflammatory disease activity in multiple sclerosis (MS) and could have an important role in MS pathology.AimTo investigate the association between myxovirus resistance protein A (MxA) mRNA levels in blood and disease activity and progression in MS over a long-term follow-up period.MethodsBaseline blood MxA mRNA levels were determined in a prospective cohort of 116 untreated patients with a clinically isolated syndrome (CIS) or early relapsing remitting MS (RRMS), and related to long-term relapses, radiological disease activity, clinical scores [Expanded Disability Status Scale (EDSS), timed-25-foot walk (T25FW), 9-hole-peg test (9HPT)], MS type, and disease modifying therapy (DMT) use.ResultsLow MxA mRNA levels were associated with the occurrence of ≥9 T2-lesions on MRI imaging and the occurrence of relapses during long-term follow-up (median 11 years, IQR 5.91–13.69 years). MxA mRNA levels were not associated with EDSS, T25FW, 9HPT, and MS subtype.ConclusionBaseline MxA mRNA levels are associated with long-term development of T2-lesions on MRI-scans in our cohort. This confirms the relevance of the endogenous interferon-beta system in the occurrence of MS disease activity.

Myxovirus resistance protein A for discriminating between viral and bacterial lower respiratory tract infections in children – The TREND study

ObjectiveDiscriminating between viral and bacterial lower respiratory tract infection (LRTI) in children is challenging, leading to an excessive use of antibiotics. Myxovirus resistance protein A (MxA) is a promising biomarker for viral infections. The primary aim of the study was to assess differences in blood MxA levels between children with viral and bacterial LRTI. Secondary aims were to assess differences in blood MxA levels between children with viral LRTI and asymptomatic controls and to assess MxA levels in relation to different respiratory viruses. MethodsChildren with LRTI were enrolled as cases at Sachs' Children and Youth Hospital, Stockholm, Sweden. Nasopharyngeal aspirates and blood samples for analysis of viral PCR, MxA, and C-reactive protein were systematically collected from all study subjects in addition to standard laboratory/radiology assessment. Aetiology was defined according to an algorithm based on laboratory and radiological findings. Asymptomatic children with minor surgical disease were enrolled as controls. ResultsMxA levels were higher in children with viral LRTI (n = 242) as compared to both bacterial (n = 5) LRTI (p <0.01, area under the curve (AUC) 0.90, 95% CI: 0.81 to 0.99), and controls (AUC 0.92, 95% CI: 0.88 to 0.95). In the subgroup of children with pneumonia diagnosis, a cutoff of MxA 430 μg/l discriminated between viral (n = 29) and bacterial (n = 4) aetiology with 93% (95% CI: 78–99%) sensitivity and 100% (95% CI: 51–100%) specificity (AUC 0.98, 95% CI: 0.94 to 1.00). The highest MxA levels were seen in cases PCR positive for influenza (median MxA 1699 μg/l, interquartile range: 732 to 2996) and respiratory syncytial virus (median MxA 1115 μg/l, interquartile range: 679 to 2489). DiscussionMxA accurately discriminated between viral and bacterial aetiology in children with LRTI, particularly in the group of children with pneumonia diagnosis, but the number of children with bacterial LRTI was low.

1034. FebriDx use in Immunocompromised Patients in a Real-World Hospital Setting during the second (COVID-19) wave in Italy

BackgroundThe diagnosis of acute respiratory infection (ARI) in patients with immunosuppression secondary to disease or medications is often unclear. Symptoms may be absent or blunted, and acute phase reactants, like procalcitonin (PCT) and C-reactive protein (CRP) may not elevate. For these patients, minor signs or symptoms could lead to hospitalization and antibiotic prescriptions to prevent complications or death. FebriDx® is a rapid, qualitative immunoassay test designed to distinguish between viral or bacterial respiratory infection through simultaneous detection of both CRP and Myxovirus resistance protein A (MxA) from a fingerstick blood sample. MethodsFebriDx was evaluated as part of a real-world prospective, observational study in hospitalized patients with symptoms of ARI and suspected COVID-19 in a single tertiary care center in Italy (August, 2020 - January, 2021). A sub analysis of patients with expected reduced host immune responses secondary to immunosuppression by disease or medication was performed. (Classified by treating clinician; patient on high dose steroids/ immunosuppressive therapy, or underlying condition like cancer or autoimmune disease). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratios were calculated for FebriDx with respect to the final diagnosis.ResultsWe included 28 patients from 200 in the study, 16 patients had a final diagnosis of bacterial infection and 12 had viral infection. FebriDx showed a sensitivity of 91.7% to accurately diagnose viral infection and 93.8% for bacterial infection (see tables). Serum CRP was not available for 4 of the patients included (14%) and elevated in the remaining patients. PCT was not available for one patient with viral infection and was elevated in 50.0%. FebriDx Performance when compared to Clinical DiagnosisConclusionFebriDx demonstrated a higher accuracy for differentiating bacterial vs. viral infection in an immunocompromised cohort than single biomarkers CRP and PCT. FebriDx demonstrated a high diagnostic accuracy to differentiate viral from bacterial infection in patients with chronic immunosuppressive conditions in a real-world setting and had better performance than standalone CRP and PCT to distinguish viral and bacterial ARI in immunocompromised patients. Disclosures Catalina Suarez-Cuervo, MD, Lumos Diagnostics (Employee)

Economic Evaluation of FebriDx®: A Novel Rapid, Point-of-Care Test for Differentiation of Viral versus Bacterial Acute Respiratory Infection in the United States

Background: Acute respiratory infections (ARIs) are commonly treated with antibiotics in outpatient settings, but many infections are caused by viruses and antibiotic treatment is therefore inappropriate. FebriDx®, a rapid point-of-care test that can differentiate viral from bacterial infections, can inform antibiotic treatment decisions. Objectives: The primary aim of this study is to conduct a literature-based US economic evaluation of a novel rapid point-of-care test, FebriDx®, that simultaneously measures two key infection biomarkers, C-reactive protein (CRP) and\ Myxovirus resistance protein A (MxA), to accurately differentiate viral from bacterial infection. Methods: A budget impact model was developed based on a review of published literature on antibiotic prescribing for ARIs in the United States. The model considers the cost of antibiotic treatment, antibiotic resistant infections, antibiotic-related adverse events, and point-of-care testing. These costs were extrapolated to estimate savings on a national level. Results: The expected national cost to treat ARIs under standard of care was US $8.25 billion, whereas the expected national cost of FebriDx point-of-care-guided ARI treatment was US $5.74 billion. Therefore, the expected national savings associated with FebriDx® rapid point-of-care testing was US $2.51 billion annually. Conclusions: FebriDx, a point of care test that can reliably aid in the differentiation of viral and bacterial infections, can reduce antibiotic misuse and, therefore, antibiotic resistant infections. This results in significant cost savings, driven primarily by the reduction in antibiotic resistant infections.

Economic Evaluation of FebriDx®: A Novel Rapid, Point-of-Care Test for Differentiation of Viral versus Bacterial Acute Respiratory Infection in the United States.

Background: Acute respiratory infections (ARIs) are commonly treated with antibiotics in outpatient settings, but many infections are caused by viruses and antibiotic treatment is therefore inappropriate. FebriDx®, a rapid point-of-care test that can differentiate viral from bacterial infections, can inform antibiotic treatment decisions.Objectives: The primary aim of this study is to conduct a literature-based US economic evaluation of a novel rapid point-of-care test, FebriDx®, that simultaneously measures two key infection biomarkers, C-reactive protein (CRP) and Myxovirus resistance protein A (MxA), to accurately differentiate viral from bacterial infection.Methods: A budget impact model was developed based on a review of published literature on antibiotic prescribing for ARIs in the United States. The model considers the cost of antibiotic treatment, antibiotic resistant infections, antibiotic-related adverse events, and point-of-care testing. These costs were extrapolated to estimate savings on a national level.Results: The expected national cost to treat ARIs under standard of care was US $8.25 billion, whereas the expected national cost of FebriDx point-of-care-guided ARI treatment was US $5.74 billion. Therefore, the expected national savings associated with FebriDx® rapid point-of-care testing was US $2.51 billion annually.Conclusions: FebriDx, a point of care test that can reliably aid in the differentiation of viral and bacterial infections, can reduce antibiotic misuse and, therefore, antibiotic resistant infections. This results in significant cost savings, driven primarily by the reduction in antibiotic resistant infections.

Myxovirus resistance protein A activates type I IFN signaling pathway to inhibit Zika virus replication

Myxovirus resistance protein A(MxA), one of the dynamin superfamily of large guanosine triphosphatase and a classical interferon stimulated gene (ISG) induced by type I interferons (IFNs), plays antiviral role in various virus infections. However, the effect of MxA on Zika virus (ZIKV) infection and its underlying mechanism remain elusive. In this study, we aimed to explore the role of MxA in ZIKV infection and its potential mechanisms. MxA overexpression was achieved by transfection with plasmid. The levels of MxA expression and ZIKV replication were assayed by both qRT-PCR and western blot. The activation status of Jak/STAT signaling pathway was evaluated at three levels: phosphorylation of STAT1 and STAT2(p-STAT1, p-STAT2) (western blot), activity of interferon sensitive response element (ISRE) (dual luciferase reporter gene assay), and the expression levels of ISGs (qRT-PCR). Our results showed that MxA overexpression inhibited ZIKV replication with no effect on virus entry. The expression levels of retinoic acid inducible gene I (RIG-I), melanoma differentiation-associated gene-5(MDA5), Toll-like receptor3(TLR3) and interferon regulatory Factor 3(IRF3), as well as IFNα and IFNβ, were increased in parallel with MxA upregulation. Interestingly, the inhibitory effect of MxA on ZIKV replication was abolished in type I IFN receptor (IFNAR) deficient cells (U5A). These data collectively supported that MxA inhibits ZIKV replication through activation of the type I IFN signaling pathway.

Updates on the Immunopathology in Idiopathic Inflammatory Myopathies.

To review recent advances in immunopathology for idiopathic inflammatory myopathies, focusing on widely available immunohistochemical analyses. Sarcoplasmic expression of myxovirus resistance protein A (MxA) is specifically observed in all types of dermatomyositis and informs that type I interferons are crucially involved in its pathogenesis. It is a more sensitive diagnostic marker than perifascicular atrophy. Diffuse tiny dots in the sarcoplasm highlighted by p62 immunostaining are characteristically seen in immune-mediated necrotizing myopathy. This feature is linked to a chaperone-assisted selective autophagy pathway. Myofiber invasion by highly differentiated T cells, a marker of which is KLRG1, is specific to inclusion body myositis and has a crucial role in its pathogenesis. The recent advances in immunopathology contribute to increased diagnostic accuracy and a better understanding of the underlying pathophysiology in different types of idiopathic inflammatory myopathies.

Skeletal Muscle and Peripheral Nerve Histopathology in COVID-19.

To explore the spectrum of skeletal muscle and nerve pathology of patients who died after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and to assess for direct viral invasion of these tissues. Psoas muscle and femoral nerve sampled from 35 consecutive autopsies of patients who died after SARS-CoV-2 infection and 10 SARS-CoV-2-negative controls were examined under light microscopy. Clinical and laboratory data were obtained by chart review. In SARS-CoV-2-positive patients, mean age at death was 67.8 years (range 43-96 years), and the duration of symptom onset to death ranged from 1 to 49 days. Four patients had neuromuscular symptoms. Peak creatine kinase was elevated in 74% (mean 959 U/L, range 29-8,413 U/L). Muscle showed type 2 atrophy in 32 patients, necrotizing myopathy in 9, and myositis in 7. Neuritis was seen in 9. Major histocompatibility complex-1 (MHC-1) expression was observed in all cases of necrotizing myopathy and myositis and in 8 additional patients. Abnormal expression of myxovirus resistance protein A (MxA) was present on capillaries in muscle in 9 patients and in nerve in 7 patients. SARS-CoV-2 immunohistochemistry was negative in muscle and nerve in all patients. In the 10 controls, muscle showed type 2 atrophy in all patients, necrotic muscle fibers in 1, MHC-1 expression in nonnecrotic/nonregenerating fibers in 3, MxA expression on capillaries in 2, and inflammatory cells in none, and nerves showed no inflammatory cells or MxA expression. Muscle and nerve tissue demonstrated inflammatory/immune-mediated damage likely related to release of cytokines. There was no evidence of direct SARS-CoV-2 invasion of these tissues. This study provides Class IV evidence that muscle and nerve biopsies document a variety of pathologic changes in patients dying of coronavirus disease 2019 (COVID-19).

Use of the FebriDx point-of-care test for the exclusion of SARS-CoV-2 diagnosis in a population with acute respiratory infection during the second (COVID-19) wave in Italy

ObjectiveEvaluate the real-world accuracy of Myxovirus resistance protein A (MxA) detected by the rapid, point-of-care FebriDx test during the second-wave pandemic in Italy in patients with acute respiratory infection (ARI) and a clinical suspicion of COVID-19. Design and methodsProspective, observational, diagnostic accuracy study whereby hospitalized patients with ARI were consecutively enrolled in a single tertiary care center in Italy from August 1, 2020 to January 31, 2021. ResultsCOVID-19 was diagnosed in 136/200 (68.0%) patients and Non-COVID-19 was diagnosed in 64/200 (32.0%) patients. COVID-19 patients were younger and had a lower Charlson comorbidity index compared to Non-COVID-19 patients (p < 0.001). Concordance between FebriDx, MxA and rt-PCR for SARS-CoV-2 (gold standard) was good (k 0.93, 95% CI 0.87–0.99). Overall sensitivity and specificity were 97.8% [95% CI 93.7–99.5] and 95.3% [95% CI 86.9%–99.0%], respectively. FebriDx demonstrated a negative predictive value of 95.3% (95% CI 86.9–99.0) for an observed disease prevalence of 68%. ConclusionsFebriDx MxA showed high diagnostic accuracy to identify COVID-19 and could be considered as a real-time triage tool to streamline the management of suspected COVID-19 patients. FebriDx also detected bacterial etiology in Non-COVID-19 patients suggesting good performance to distinguish bacterial from viral respiratory infection.

Poly(dA:dT) Suppresses HSV-2 Infection of Human Cervical Epithelial Cells Through RIG-I Activation.

Epithelial cells of the female reproductive tract (FRT) participate in the initial innate immunity against viral infections. Poly(dA:dT) is a synthetic analog of B form double-stranded (ds) DNA which can activate the interferon (IFN) signaling pathway-mediated antiviral immunity through DNA-dependent RNA Polymerase III. Here we investigated whether poly(dA:dT) could inhibit herpes simplex virus type 2 (HSV-2) infection of human cervical epithelial cells (End1/E6E7). We demonstrated that poly(dA:dT) treatment of End1/E6E7 cells could significantly inhibit HSV-2 infection. Mechanistically, poly(dA:dT) treatment of the cells induced the expression of the intracellular IFNs and the multiple antiviral IFN-stimulated genes (ISGs), including IFN-stimulated gene 15 (ISG15), IFN-stimulated gene 56 (ISG56), 2’-5’-oligoadenylate synthetase 1 (OAS1), 2’-5’-oligoadenylate synthetase 2 (OAS2), myxovirus resistance protein A (MxA), myxovirus resistance protein B (MxB), virus inhibitory protein, endoplasmic reticulum-associated, IFN-inducible (Viperin), and guanylate binding protein 5 (GBP5). Further investigation showed that the activation of RIG-I was largely responsible for poly(dA:dT)-mediated HSV-2 inhibition and IFN/ISGs induction in the cervical epithelial cells, as RIG-I knockout abolished the poly(dA:dT) actions. These observations demonstrate the importance for design and development of AT-rich dsDNA-based intervention strategies to control HSV-2 mucosal transmission in FRT.

Tick-transmitted thogotovirus gains high virulence by a single MxA escape mutation in the viral nucleoprotein.

Infections with emerging and re-emerging arboviruses are of increasing concern for global health. Tick-transmitted RNA viruses of the genus Thogotovirus in the Orthomyxoviridae family have considerable zoonotic potential, as indicated by the recent emergence of Bourbon virus in the USA. To successfully infect humans, arboviruses have to escape the restrictive power of the interferon defense system. This is exemplified by the high sensitivity of thogotoviruses to the antiviral action of the interferon-induced myxovirus resistance protein A (MxA) that inhibits the polymerase activity of incoming viral ribonucleoprotein complexes. Acquiring resistance to human MxA would be expected to enhance the zoonotic potential of these pathogens. Therefore, we screened a panel of 10 different thogotovirus isolates obtained from various parts of the world for their sensitivity to MxA. A single isolate from Nigeria, Jos virus, showed resistance to the antiviral action of MxA in cell culture and in MxA-transgenic mice, whereas the prototypic Sicilian isolate SiAr126 was fully MxA-sensitive. Further analysis identified two amino acid substitutions (G327R and R328V) in the viral nucleoprotein as determinants for MxA resistance. Importantly, when introduced into SiAr126, the R328V mutation resulted in complete MxA escape of the recombinant virus, without causing any viral fitness loss. The escape mutation abolished viral nucleoprotein recognition by MxA and allowed unhindered viral growth in MxA-expressing cells and in MxA-transgenic mice. These findings demonstrate that thogotoviruses can overcome the species barrier by escaping MxA restriction and reveal that these tick-transmitted viruses may have a greater zoonotic potential than previously suspected.

Point-of-Care Approaches for Meningitis Diagnosis in a Low-Resource Setting (Southwestern Uganda): Observational Cohort Study Protocol of the "PI-POC" Trial.

BackgroundA timely differential diagnostic is essential to identify the etiology of central nervous system (CNS) infections in children, in order to facilitate targeted treatment, manage patients, and improve clinical outcome.ObjectiveThe Pediatric Infection-Point-of-Care (PI-POC) trial is investigating novel methods to improve and strengthen the differential diagnostics of suspected childhood CNS infections in low-income health systems such as those in Southwestern Uganda. This will be achieved by evaluating (1) a novel DNA-based diagnostic assay for CNS infections, (2) a commercially available multiplex PCR-based meningitis/encephalitis (ME) panel for clinical use in a facility-limited laboratory setting, (3) proteomics profiling of blood from children with severe CNS infection as compared to outpatient controls with fever yet not severely ill, and (4) Myxovirus resistance protein A (MxA) as a biomarker in blood for viral CNS infection. Further changes in the etiology of childhood CNS infections after the introduction of the pneumococcal conjugate vaccine against Streptococcus pneumoniae will be investigated. In addition, the carriage and invasive rate of Neisseria meningitidis will be recorded and serotyped, and the expression of its major virulence factor (polysaccharide capsule) will be investigated.MethodsThe PI-POC trial is a prospective observational study of children including newborns up to 12 years of age with clinical features of CNS infection, and age-/sex-matched outpatient controls with fever yet not severely ill. Participants are recruited at 2 Pediatric clinics in Mbarara, Uganda. Cerebrospinal fluid (for cases only), blood, and nasopharyngeal (NP) swabs (for both cases and controls) sampled at both clinics are analyzed at the Epicentre Research Laboratory through gold-standard methods for CNS infection diagnosis (microscopy, biochemistry, and culture) and a commercially available ME panel for multiplex PCR analyses of the cerebrospinal fluid. An additional blood sample from cases is collected on day 3 after admission. After initial clinical analyses in Mbarara, samples will be transported to Stockholm, Sweden for (1) validation analyses of a novel nucleic acid–based POC test, (2) biomarker research, and (3) serotyping and molecular characterization of S. pneumoniae and N. meningitidis.ResultsA pilot study was performed from January to April 2019. The PI-POC trial enrollment of patients begun in April 2019 and will continue until September 2020, to include up to 300 cases and controls. Preliminary results from the PI-POC study are expected by the end of 2020.ConclusionsThe findings from the PI-POC study can potentially facilitate rapid etiological diagnosis of CNS infections in low-resource settings and allow for novel methods for determination of the severity of CNS infection in such environment.Trial RegistrationClinicalTrials.gov NCT03900091; https://clinicaltrials.gov/ct2/show/NCT03900091International Registered Report Identifier (IRRID)DERR1-10.2196/21430

Evaluation of C-reactive protein and myxovirus resistance protein A to guide the rational use of antibiotics among acute febrile adult patients in Northwest Ethiopia

ObjectivesIn low-resource settings, treatment is often given empirically without knowledge of the aetiology due to a lack of diagnostics. In the search for reliable rapid tests to guide treatment work-up, this study was performed to determine whether two biomarkers could differentiate bacterial from non-bacterial infections in acute febrile patients. MethodsAdults with acute fever were recruited at a referral hospital in Ethiopia. The QuikRead Go test was used to quantify C-reactive protein (qCRP) and the FebriDx test was used for combined qualitative detection of the bacterial CRP marker with myxovirus resistance protein A (MxA), a viral biomarker. ResultsOf the 200 patients included in this study, most presented with 2–3 days of fever, headache, and joint pain. Antibiotics were prescribed for 83.5% and antimalarials for 36.5%, while a bacterial infection was only confirmed in 5% and malaria in 11%. The median qCRP level for confirmed bacterial infections was 128 mg/l. The FebriDx and QuikRead Go test had an overall agreement of 72.0%. ConclusionsAn over-prescription of antibiotics for febrile patients was observed, even for those with low CRP levels and without a confirmed bacterial infection. The added value of the FebriDx was limited, while the combined use of rapid tests for qCRP and malaria should be considered for the management of acute febrile illness and antibiotic stewardship.

Utility of the FebriDx point-of-care test for rapid triage and identification of possible coronavirus disease 2019 (COVID-19).

ObjectivesThe Coronavirus disease 2019 (COVID‐19) pandemic is straining healthcare resources. Molecular testing turnaround time precludes having results at the point‐of‐care (POC) thereby exposing COVID‐19/Non‐COVID‐19 patients while awaiting diagnosis. We evaluated the utility of a triage strategy including FebriDx, a 10‐minute POC finger‐stick blood test that differentiates viral from bacterial acute respiratory infection through detection of Myxovirus‐resistance protein A (MxA) and C‐reactive protein (CRP), to rapidly isolate viral cases requiring confirmatory testing.MethodsThis observational, prospective, single‐center study enrolled patients presenting to/within an acute care hospital in England with suspected COVID‐19 between March and April 2020. Immunocompetent patients ≥16 years requiring hospitalisation with pneumonia or acute respiratory distress syndrome or influenza‐like illness (fever and ≥1 respiratory symptom within 7 days of enrolment, or inpatients with new respiratory symptoms, fever of unknown cause or pre‐existing respiratory condition worsening). The primary endpoint was diagnostic performance of FebriDx to identify COVID‐19 as a viral infection; secondary endpoint was SARS‐CoV‐2 molecular test diagnostic performance compared with the reference standard COVID‐19 Case Definition (molecular or antibody detection of SARS‐CoV‐2).ResultsValid results were available for 47 patients. By reference standard, 35 had viral infections (34/35 COVID‐19; 1/35 non‐COVID‐19; overall FebriDx viral sensitivity 97.1% (95%CI 83.3‐99.9)). Of the COVID‐19 cases, 34/34 were FebriDx viral positive (sensitivity 100%; 95%CI 87.4‐100); 29/34 had an initial SARS‐CoV‐2 positive molecular test (sensitivity 85.3%; 95%CI 68.2‐94.5). FebriDx was viral negative when the diagnosis was not COVID‐19 and SARS‐Cov‐2 molecular test was negative (negative predictive value (NPV) 100% (13/13; 95%CI 71.7‐100)) exceeding initial SARS‐CoV‐2 molecular test NPV 72.2% (13/19; 95%CI 46.4‐89.3). The diagnostic specificity of FebriDx and initial SARS‐CoV‐2 molecular test was 100% (13/13; 95%CI 70‐100 and 13/13; 95%CI 85.4‐100, respectively).ConclusionsFebriDx could be deployed as part of a reliable triage strategy for identifying symptomatic cases as possible COVID‐19 in the pandemic.