RESUMEN
Excessive inflammatory responses contribute to the pathogenesis and lethality of highly pathogenic human coronaviruses, but the underlying mechanism remains unclear. In this study, the N proteins of highly pathogenic human coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV), middle east respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were found to bind MASP-2, a key serine protease in the lectin pathway of complement activation, resulting in excessive complement activation by potentiating MBL-dependent MASP-2 activation, and the deposition of MASP-2, C4b, activated C3 and C5b-9. Aggravated inflammatory lung injury was observed in mice infected with adenovirus expressing the N protein. Complement hyperactivation was also observed in SARS-CoV-2-infected patients. Either blocking the N protein:MASP-2 interaction, MASP-2 depletion or suppressing complement activation can significantly alleviate N protein-induced complement hyperactivation and lung injury in vitro and in vivo. Altogether, these data suggested that complement suppression may represent a novel therapeutic approach for pneumonia induced by these highly pathogenic coronaviruses.
Asunto(s)
COVID-19 , Lesión Pulmonar , Animales , COVID-19/genética , Lectina de Unión a Manosa de la Vía del Complemento/genética , Proteínas de la Nucleocápside de Coronavirus , Humanos , Inflamación/genética , Serina Proteasas Asociadas a la Proteína de Unión a la Manosa/genética , Serina Proteasas Asociadas a la Proteína de Unión a la Manosa/metabolismo , Ratones , SARS-CoV-2RESUMEN
Objective: To investigate the effect of sampling positions in nucleic acid test for COVID-19 on test results.
RESUMEN
Objective: To retrospectively analyze a family cluster of coronavirus disease 2019(COVID-19) with unknown cause in Jinan City.
Asunto(s)
COVID-19/diagnóstico , Coinfección/microbiología , Nasofaringe/microbiología , Esputo/microbiología , Transcriptoma/genética , Bacterias/aislamiento & purificación , COVID-19/virología , China , Coinfección/diagnóstico , Hongos/aislamiento & purificación , Humanos , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación , Virus/aislamiento & purificaciónRESUMEN
The early detection and differential diagnosis of respiratory infections increase the chances for successful control of COVID-19 disease. The nucleic acid RT-PCR test is regarded as the current standard for molecular diagnosis. However, the maximal specificity confirmation target ORF1ab gene is considered to be less sensitive than other targets in clinical application. In addition, recent evidence indicated that the initial missed diagnosis of asymptomatic patients with SARS-CoV-2 and discharged patients with "re-examination positive" might be due to low viral load, and the ability of rapid mutation of SARS-CoV-2 also increases the rate of false-negative results. Moreover, the mixed sample nucleic acid detection is helpful in seeking out the early community transmission of SARS-CoV-2 rapidly, but the detection kit needs ultra-high detection sensitivity. Herein, the lowest detection concentration of different nucleic acid detection kits was evaluated and compared to provide direct evidence for the selection of kits for mixed sample detection or make recommendations for the selection of validation kit, which is of great significance for the prevention and control of the current epidemic and the discharge criteria of low viral load patients.
Asunto(s)
Límite de Detección , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , SARS-CoV-2/aislamiento & purificación , Adolescente , Adulto , Niño , Reacciones Falso Negativas , Femenino , Humanos , Masculino , Persona de Mediana Edad , SARS-CoV-2/genética , Adulto JovenRESUMEN
BACKGROUND: Real-time reverse transcription-PCR (rRT-PCR) has been the most effective and widely implemented diagnostic technology since the beginning of the COVID-19 pandemic. However, fuzzy rRT-PCR readouts with high Ct values are frequently encountered, resulting in uncertainty in diagnosis. METHODS: A Specific Enhancer for PCR-amplified Nucleic Acid (SENA) was developed based on the Cas12a trans-cleavage activity, which is specifically triggered by the rRT-PCR amplicons of the SARS-CoV-2 Orf1ab (O) and N fragments. SENA was first characterized to determine its sensitivity and specificity, using a systematic titration experiment with pure SARS-CoV-2 RNA standards, and was then verified in several hospitals, employing a couple of commercial rRT-PCR kits and testing various clinical specimens under different scenarios. FINDINGS: The ratio (10 min/5 min) of fluorescence change (FC) with mixed SENA reaction (mix-FCratio) was defined for quantitative analysis of target O and N genes, and the Limit of Detection (LoD) of mix-FCratio with 95% confidence interval was 1.2≤1.6≤2.1. Totally, 295 clinical specimens were analyzed, among which 21 uncertain rRT-PCR cases as well as 4 false negative and 2 false positive samples were characterized by SENA and further verified by next-generation sequencing (NGS). The cut-off values for mix-FCratio were determined as 1.145 for positive and 1.068 for negative. INTERPRETATION: SENA increases both the sensitivity and the specificity of rRT-PCR, solving the uncertainty problem in COVID-19 diagnosis and thus providing a simple and low-cost companion diagnosis for combating the pandemic. FUNDING: Detailed funding information is available at the end of the manuscript.