ABSTRACT
The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays a key role in viral infectivity. It is also the major antigen stimulating the host's protective immune response, specifically, the production of neutralizing antibodies. Recently, a new variant of SARS-CoV-2 possessing multiple mutations in the S protein, designated P.1, emerged in Brazil. Here, we characterized a P.1 variant isolated in Japan by using Syrian hamsters, a well-established small animal model for the study of SARS-CoV-2 disease (COVID-19). In hamsters, the variant showed replicative abilities and pathogenicity similar to those of early and contemporary strains (i.e., SARS-CoV-2 bearing aspartic acid [D] or glycine [G] at position 614 of the S protein). Sera and/or plasma from convalescent patients and BNT162b2 messenger RNA vaccinees showed comparable neutralization titers across the P.1 variant, S-614D, and S-614G strains. In contrast, the S-614D and S-614G strains were less well recognized than the P.1 variant by serum from a P.1-infected patient. Prior infection with S-614D or S-614G strains efficiently prevented the replication of the P.1 variant in the lower respiratory tract of hamsters upon reinfection. In addition, passive transfer of neutralizing antibodies to hamsters infected with the P.1 variant or the S-614G strain led to reduced virus replication in the lower respiratory tract. However, the effect was less pronounced against the P.1 variant than the S-614G strain. These findings suggest that the P.1 variant may be somewhat antigenically different from the early and contemporary strains of SARS-CoV-2.
Subject(s)
COVID-19/virology , SARS-CoV-2/physiology , SARS-CoV-2/pathogenicity , Virus Replication , Animals , Antibodies, Neutralizing , COVID-19/diagnostic imaging , COVID-19/pathology , Cricetinae , Humans , Immunogenicity, Vaccine , Lung/pathology , Mesocricetus , Mice , Spike Glycoprotein, Coronavirus/genetics , X-Ray MicrotomographyABSTRACT
BACKGROUND: Patients with obstructive sleep apnea syndrome (OSAS) experience excessive daytime sleepiness and insomnia and they are at risk of developing cardiovascular disease and stroke. Continuous positive airway pressure therapy could improve symptoms and decrease these risks; however, adherence is problematic. Although the oral appliance is another therapeutic option, patient satisfaction is limited and the effect of the nasal airway stent - a new device - remains unclear. OBJECTIVES: The aim of this study was to evaluate the effect of NAS therapy in patients with mild-to-moderate OSAS in a prospective, single-arm, interventional pilot study. METHOD: Patients with mild/moderate sleep apnea (n = 71; Apnea-Hypopnea Index [AHI], 5-20 events/h on polysomnography) were recruited. Sleep-associated events were measured using a portable device (WatchPAT200) pre- and immediately post-treatment and at 1 month follow-up. AHI (including supine and non-supine AHI), Oxygen Desaturation Index (ODI), Respiratory Disturbance Index (RDI), percutaneous oxygen saturation, heart rate, and snore volume were evaluated. Symptoms were assessed using the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, and Hospital Anxiety and Depression Scale. RESULTS: NAS use significantly improved AHI, supine AHI, RD, ODI, and snore volume compared to pre-intervention (r = 0.44, 0.48, 0.3, 0.42, and 0.34; p < 0.001, p < 0.001, p = 0.011, p < 0.001, and p = 0.048, respectively). Additionally, 25 and 10% of patients showed complete and partial response for AHI, respectively; these improvements remained significant 1 month later. Pittsburgh Sleep Quality Index scores improved from 6.0 to 5.3 (r = 0.46, p = 0.022). CONCLUSIONS: NAS therapy reduced severity and snoring in patients with mild-to-moderate OSAS. Approximately 30% of patients did not tolerate NAS due to side effects.
Subject(s)
Airway Management , Sleep Apnea, Obstructive , Snoring , Stents , Airway Management/adverse effects , Airway Management/instrumentation , Airway Management/methods , Disorders of Excessive Somnolence/diagnosis , Disorders of Excessive Somnolence/etiology , Disorders of Excessive Somnolence/therapy , Female , Heart Rate Determination/methods , Humans , Male , Middle Aged , Outcome Assessment, Health Care , Oxygen Consumption , Pilot Projects , Polysomnography/methods , Sleep Apnea, Obstructive/complications , Sleep Apnea, Obstructive/diagnosis , Sleep Apnea, Obstructive/physiopathology , Sleep Apnea, Obstructive/therapy , Sleep Initiation and Maintenance Disorders/diagnosis , Sleep Initiation and Maintenance Disorders/etiology , Sleep Initiation and Maintenance Disorders/therapy , Sleep Quality , Snoring/diagnosis , Snoring/etiology , Snoring/therapy , Treatment OutcomeABSTRACT
BACKGROUND: Some patients with severe asthma also have fungal sensitization and are considered to have severe asthma with fungal sensitization. However, there is limited information on the clinical features of SAFS. OBJECTIVE: To investigate the clinical characteristics of severe asthma with fungal sensitization. METHODS: The present study enrolled 124 patients with severe asthma. We evaluated clinical aspects, such as various serum cytokines, fractional exhaled nitric oxide, pulmonary function, and serum immunoglobulin E (IgE). Fungal sensitization was assessed by determining serum levels of IgE specific to fungal allergens (Aspergillus, Alternaria, Candida, Cladosporium, Penicillium, and Trichophyton species and Schizophyllum commune). The protocol was registered at a clinical trial registry (www.umin.ac.jp/ctr/index-j.htm; UMIN 000002980). RESULTS: Thirty-six patients (29%) showed sensitization to at least 1 fungal allergen. The most common species were Candida (16%), Aspergillus (11%), and Trichophyton (11%). The rate of early-onset asthma (<16 years of age) was higher in patients with fungal sensitization than in those without fungal sensitization (45% vs 25%; P = .02). Interleukin-33 levels were higher in patients with fungal sensitization than in those without fungal sensitization. Of patients with atopic asthma, Asthma Control Test scores were worse in patients with multiple fungal sensitizations than in patients with a single fungal sensitization or those without fungal sensitization. CONCLUSION: Severe asthma with fungal sensitization is characterized by early onset of disease and high serum levels of interleukin-33. Multiple fungal sensitizations are associated with poor asthma control. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR; www.umin.ac.jp/ctr/index-j.htm): UMIN 000002980.
Subject(s)
Allergens/immunology , Antigens, Fungal/immunology , Asthma/epidemiology , Adult , Aged , Aged, 80 and over , Asthma/blood , Asthma/metabolism , Asthma/physiopathology , Cytokines/blood , Female , Forced Expiratory Volume , Fungi/immunology , Humans , Immunoglobulin E/blood , Immunoglobulin E/immunology , Male , Middle Aged , Nitric Oxide/metabolism , Severity of Illness Index , Young AdultABSTRACT
Quantification of cytokine secretion has facilitated advances in the field of immunology, yet the dynamic and varied secretion profiles of individual cells, particularly those obtained from limited human samples, remain obscure. Herein, we introduce a technology for quantitative live-cell imaging of secretion activity (qLCI-S) that enables high-throughput and dual-color monitoring of secretion activity at the single-cell level over several days, followed by transcriptome analysis of individual cells based on their phenotype. The efficacy of qLCI-S was demonstrated by visualizing the characteristic temporal pattern of cytokine secretion of group 2 innate lymphoid cells, which constitute less than 0.01% of human peripheral blood mononuclear cells, and by revealing minor subpopulations with enhanced cytokine production. The underlying mechanism of this feature was linked to the gene expression of stimuli receptors. This technology paves the way for exploring gene expression signatures linked to the spatiotemporal dynamic nature of various secretory functions.
ABSTRACT
BACKGROUND: Allergic bronchopulmonary mycosis (ABPM) is an allergic disease caused by type I and type III hypersensitivity to environmental fungi. Schizophyllum commune, a basidiomycete fungus, is one of the most common fungi that causes non-Aspergillus ABPM. OBJECTIVE: Herein, we attempted to clarify the clinical characteristics of ABPM caused by S. commune (ABPM-Sc) compared with those of allergic bronchopulmonary aspergillosis (ABPA). METHODS: Patients with ABPM-Sc or ABPA were recruited from a nationwide survey in Japan, a multicenter cohort, and a fungal database at the Medical Mycology Research Center of Chiba University. The definition of culture-positive ABPM-Sc/ABPA is as follows: (1) fulfills five or more of the 10 diagnostic criteria for ABPM proposed by Asano et al., and (2) positive culture of S. commune/Aspergillus spp. in sputum, bronchial lavage fluid, or mucus plugs in the bronchi. RESULTS: Thirty patients with ABPM-Sc and 46 with ABPA were recruited. Patients with ABPM-Sc exhibited less severe asthma and presented with better pulmonary function than those with ABPA (p = 0.008-0.03). Central bronchiectasis was more common in ABPM-Sc than that in ABPA, whereas peripheral lung lesions, including infiltrates/ground-glass opacities or fibrotic/cystic changes, were less frequent in ABPM-Sc. Aspergillus fumigatus-specific immunoglobulin (Ig)E was negative in 10 patients (34%) with ABPM-Sc, who demonstrated a lower prevalence of asthma and levels of total serum IgE than those with ABPM-Sc positive for A. fumigatus-specific IgE or ABPA. CONCLUSIONS: Clinical characteristics of ABPM-Sc, especially those negative for A. fumigatus-specific IgE, differed from those of ABPA.
ABSTRACT
Group 2 innate lymphoid cells (ILC2s) produce large amounts of type 2 cytokines including interleukin-5 (IL-5) and IL-13 in response to various stimuli, causing allergic and eosinophilic diseases. However, the cell-intrinsic regulatory mechanisms of human ILC2s remain unclear. Here, we analyze human ILC2s derived from different tissues and pathological conditions and identify ANXA1, encoding annexin A1, as a commonly highly expressed gene in non-activated ILC2s. The expression of ANXA1 decreases when ILC2s activate, but it increases autonomously as the activation subsides. Lentiviral vector-based gene transfer experiments show that ANXA1 suppresses the activation of human ILC2s. Mechanistically, ANXA1 regulates the expression of the metallothionein family genes, including MT2A, which modulate intracellular zinc homeostasis. Furthermore, increased intracellular zinc levels play an essential role in the activation of human ILC2s by promoting the mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways and GATA3 expression. Thus, the ANXA1/MT2A/zinc pathway is identified as a cell-intrinsic metalloregulatory mechanism for human ILC2s.
Subject(s)
Annexin A1 , Immunity, Innate , Humans , Lymphocytes/metabolism , Zinc/metabolism , Cytokines/metabolismABSTRACT
SARS-CoV-2 has gradually acquired amino acid substitutions in its S protein that reduce the potency of neutralizing antibodies, leading to decreased vaccine efficacy. Here, we attempted to obtain mutant viruses by passaging SARS-CoV-2 in the presence of plasma samples from convalescent patients or vaccinees to determine which amino acid substitutions affect the antigenicity of SARS-CoV-2. Several amino acid substitutions in the S2 region, as well as the N-terminal domain (NTD) and receptor-binding domain (RBD), affected the neutralization potency of plasma samples collected from vaccinees, indicating that amino acid substitutions in the S2 region as well as those in the NTD and RBD affect neutralization by vaccine-induced antibodies. Furthermore, the neutralizing potency of vaccinee plasma samples against mutant viruses we obtained or circulating viruses differed among individuals. These findings suggest that genetic backgrounds of vaccinees influence the recognition of neutralizing epitopes.
ABSTRACT
The detailed mechanisms of COVID-19 infection pathology remain poorly understood. To improve our understanding of SARS-CoV-2 pathology, we performed a multi-omics and correlative analysis of an immunologically naïve SARS-CoV-2 clinical cohort from blood plasma of uninfected controls, mild, and severe infections. Consistent with previous observations, severe patient populations showed an elevation of pulmonary surfactant levels. Intriguingly, mild patients showed a statistically significant elevation in the carnosine dipeptidase modifying enzyme (CNDP1). Mild and severe patient populations showed a strong elevation in the metabolite L-cystine (oxidized form of the amino acid cysteine) and enzymes with roles in glutathione metabolism. Neutrophil extracellular traps (NETs) were observed in both mild and severe populations, and NET formation was higher in severe vs. mild samples. Our correlative analysis suggests a potential protective role for CNDP1 in suppressing PSPB release from the pulmonary space whereas NET formation correlates with increased PSPB levels and disease severity. In our discussion we put forward a possible model where NET formation drives pulmonary occlusions and CNDP1 promotes antioxidation, pleiotropic immune responses, and vasodilation by accelerating histamine synthesis.
ABSTRACT
We conducted a subgroup analysis of a study on the long-term effects of COVID-19 (long COVID) in Japan to assess the effect of vaccination on long COVID symptoms. We assessed the clinical course of 111 patients with long COVID at the time of vaccination. The follow-up period was one year from the onset of COVID-19 or until the administration of the third vaccine dose. Of the 111 patients, 15 (13.5%) reported improvement, four (3.6%) reported deterioration, and 92 (82.9%) reported no change in their long COVID symptoms after vaccination. The most common long COVID symptoms before vaccination were alopecia, dyspnea, muscle weakness, fatigue, and headache among participants whose symptoms improved. Reduced dyspnea and alopecia were the most frequently reported improvements in symptoms after vaccination. Some symptoms persisted, including sleep disturbance, myalgia, and hypersensitivity. Vaccination did not appear to have a clinically important effect on patients with long COVID symptoms.
ABSTRACT
Background: To determine the effectiveness of baricitinib in patients with coronavirus disease 2019 (COVID-19), investigate whether baricitinib prevents the need for invasive mechanical ventilation and identify patient subgroups that would benefit from baricitinib. Methods: This observational matched-cohort study was conducted by the Japan COVID-19 Task Force, a nationwide multicenter consortium. Patients with COVID-19 aged ≥18 years were identified from 70 hospitals in Japan. Among patients with confirmed COVID-19 from February 2020 to September 2021, those receiving baricitinib were propensity-score matched with controls. Results: Among 3309 patients, 144 propensity score-matched pairs were identified. Thirteen (9.0%) patients in the baricitinib group and 27 (18.8%) in the control group required invasive mechanical ventilation during the disease course (odds ratio, 0.43). Although the baricitinib group had more severe disease, there were no significant differences in the intensive care unit admission rates (odds ratio, 1.16) and mortality rates (odds ratio, 0.74) between groups. In subgroup analyses, baricitinib was associated with a significant reduction in the need for invasive mechanical ventilation in patients requiring oxygen support (odds ratio, 0.28), with rapid shadow spread on chest radiography (odds ratio, 0.11), or treated with remdesivir (odds ratio, 0.27), systemic corticosteroids (odds ratio, 0.31), or anticoagulants (odds ratio, 0.17). Conclusions: Baricitinib is effective at preventing the need for invasive mechanical ventilation in patients with COVID-19.
ABSTRACT
Background: Group 2 innate lymphoid cells (ILC2s) produce type 2 cytokines by stimulation with epithelial cell-derived cytokines and are implicated in the pathogenesis of various allergic diseases, including asthma. However, differences in the molecular characteristics of ILC2s between patients with asthma and healthy subjects remain unclear. Objective: We sought to evaluate differences in cytokine production capacity and gene expression profile of ILC2s in the peripheral blood of patients with asthma and healthy subjects. Methods: We evaluated ILC2s derived from 15 patients with asthma and 7 healthy subjects using flow cytometry, live-cell imaging of secretion activity analysis, and RNA-sequencing. Results: ILC2s were sorted as CD45+Lineage-CRTH2+CD127+CD161+ cells from the peripheral blood of patients with asthma and healthy subjects, and the number of ILC2s was decreased in patients with asthma (851 ± 1134 vs 2679 ± 3009 cells/20 mL blood; P = .0066). However, patient-derived ILC2s were activated to produce more IL-5 and IL-13 in response to stimulation with IL-2, IL-33, and thymic stromal lymphopoietin compared with healthy subject-derived ILC2s (P = .0032 and P = .0085, respectively). Furthermore, RNA-sequencing analysis revealed that patient-derived ILC2s had different gene expression profiles, such as increased expression in cell growth-related genes (CDKN1b, CCNG2, CCND2, CCN1), prostaglandin E receptor (PTGER2), and IL-4 receptor. In addition, a gene set of the IL-4 receptor signaling pathway was significantly upregulated in ILC2s in patients with asthma (P = .042). Conclusions: Our results suggest that circulating ILC2s in patients with asthma are preactivated via the IL-4 receptor signaling pathway and produce IL-5 and IL-13 vigorously by stimulation.
ABSTRACT
Limited knowledge exists on immune markers associated with disease severity or recovery in patients with coronavirus disease 2019 (COVID-19). Here, we elucidated longitudinal evolution of SARS-CoV-2 antibody repertoire in patients with acute COVID-19. Differential kinetics was observed for immunoglobulin M (IgM)/IgG/IgA epitope diversity, antibody binding, and affinity maturation in "severe" versus "mild" COVID-19 patients. IgG profile demonstrated immunodominant antigenic sequences encompassing fusion peptide and receptor binding domain (RBD) in patients with mild COVID-19 who recovered early compared with "fatal" COVID-19 patients. In patients with severe COVID-19, high-titer IgA were observed, primarily against RBD, especially in patients who succumbed to SARS-CoV-2 infection. The patients with mild COVID-19 showed marked increase in antibody affinity maturation to prefusion SARS-CoV-2 spike that associated with faster recovery from COVID-19. This study revealed antibody markers associated with disease severity and resolution of clinical disease that could inform development and evaluation of effective immune-based countermeasures against COVID-19.
Subject(s)
Antibodies, Viral/blood , Antibodies, Viral/immunology , Antigens, Viral/immunology , Biomarkers/blood , COVID-19/immunology , COVID-19/pathology , SARS-CoV-2/physiology , Severity of Illness Index , Antibody Affinity/immunology , Antibody Formation/immunology , COVID-19/blood , COVID-19/virology , Cytokines/blood , HEK293 Cells , Hospitalization , Humans , Immunoglobulin Class Switching , Kinetics , Neutralization Tests , Protein Binding , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Viral LoadABSTRACT
BACKGROUND: To develop an effective vaccine against a novel viral pathogen, it is important to understand the longitudinal antibody responses against its first infection. Here we performed a longitudinal study of antibody responses against SARS-CoV-2 in symptomatic patients. METHODS: Sequential blood samples were collected from 39 individuals at various timepoints between 0 and 154 days after onset. IgG or IgM titers to the receptor binding domain (RBD) of the S protein, the ectodomain of the S protein, and the N protein were determined by using an ELISA. Neutralizing antibody titers were measured by using a plaque reduction assay. FINDINGS: The IgG titers to the RBD of the S protein, the ectodomain of the S protein, and the N protein peaked at about 20 days after onset, gradually decreased thereafter, and were maintained for several months after onset. Extrapolation modeling analysis suggested that the IgG antibodies were maintained for this amount of time because the rate of reduction slowed after 30 days post-onset. IgM titers to the RBD decreased rapidly and disappeared in some individuals after 90 days post-onset. All patients, except one, possessed neutralizing antibodies against authentic SARS-CoV-2, which they retained at 90 days after onset. The highest antibody titers in patients with severe infections were higher than those in patients with mild or moderate infections, but the decrease in antibody titer in the severe infection cohort was more remarkable than that in the mild or moderate infection cohort. INTERPRETATION: Although the number of patients is limited, our results show that the antibody response against the first SARS-CoV-2 infection in symptomatic patients is typical of that observed in an acute viral infection. FUNDING: The Japan Agency for Medical Research and Development and the National Institutes of Allergy and Infectious Diseases.
ABSTRACT
INTRODUCTION: The rapid spread of COVID-19 posed a global burden. Substantial number of people died of the disease in the acute phase of infection. In addition, a significant proportion of patients have been reported to suffer from post-acute phase symptoms, sequelae of COVID-19, which may negatively influence the quality of daily living and/or socioeconomic circumstances of the patients. However, no previous study has comprehensively and objectively assessed the quality of life of patients by using existing international scales. Further, evidence of socioeconomic consequences among patients with COVID-19 is scarce. To address the multidimensional issues from sequelae of COVID-19, evidence from comprehensive surveys beyond clinical perspectives is critical that investigates health, and social determinants of disease progression as well as socioeconomic consequences at a large scale. METHODS AND ANALYSIS: In this study, we plan to conduct a nationwide and comprehensive survey for the sequelae of COVID-19 in a total of 1000 patients diagnosed at 27 hospitals throughout Japan. This study will evaluate not only the health-related status of patients from clinical perspectives but also the Health-related Quality of Life (HRQoL) scores, socioeconomic status and consequences to discuss the sequelae of the disease and the related risk factors. The primary endpoint is the frequency of long-term complications of COVID-19 infection. The secondary endpoints are risk factors for progression to sequelae of COVID-19 infection. The study will provide robust and important evidence as a resource to tackle the issues from the sequelae of COVID-19 from the multi-dimensional perspectives. ETHICS AND DISSEMINATION: This trial was approved by the Keio University School of Medicine Ethics Committee (20200243, UMIN000042299). The results of this study will be reported at a society meeting or published in a peer-reviewed journal.
Subject(s)
COVID-19 , Cohort Studies , Disease Progression , Humans , Japan/epidemiology , Multicenter Studies as Topic , Quality of Life , SARS-CoV-2ABSTRACT
A number of preclinical studies have indicated the therapeutic potential of endothelial progenitor cells for vascular regeneration in ischemic diseases. A phase I/IIa clinical trial of transplantation of autologous CD34(+) cells, the endothelial and hematopoietic progenitor-enriched fraction, was performed in no-option patients with atherosclerotic peripheral artery disease or Buerger's disease with critical limb ischemia (CLI). CD34(+) cells were isolated from the G-CSF-mobilized apheresis product using a magnetic cell sorting system. CD34(+) cells (10(5)/kg, n = 6; 5 x 10(5)/kg, n = 8; or 10(6)/kg, n = 3) were injected i.m. into the leg with more severe ischemia. The Efficacy Score, representing changes in the toe brachial pressure index (TBPI), Wong-Baker FACES pain rating scale, and total walking distance 12 weeks after cell transplantation, the primary endpoint, was positive, indicating improvement in limb ischemia in all patients, although no significant dose-response relationship was observed. During the 12-week observation after cell therapy, the Wong-Baker FACES pain rating scale, TBPI, transcutaneous partial oxygen pressure, total or pain-free walking distance, and ulcer size serially improved in all patients. No death or major amputation occurred, and severe adverse events were rare, although mild to moderate events relating to G-CSF and leukapheresis were frequent during the 12-week follow-up. In conclusion, the outcomes of this prospective clinical study indicate the safety and feasibility of CD34(+) cell therapy in patients with CLI. Favorable trends in efficacy parameters encourage a randomized and controlled trial in the future.
Subject(s)
Antigens, CD34/metabolism , Cell- and Tissue-Based Therapy/methods , Granulocyte Colony-Stimulating Factor/metabolism , Ischemia/therapy , Leg/pathology , Stem Cells/cytology , Adult , Aged , Aged, 80 and over , Cell- and Tissue-Based Therapy/adverse effects , Female , Humans , Injections, Intramuscular , Male , Stem Cell Transplantation , Stem Cells/metabolism , Transplantation, Autologous , Treatment OutcomeABSTRACT
BACKGROUND: Inhaled medicines are key drugs for the treatment of asthma or chronic obstructive pulmonary disease. However, the variety of inhaler devices and complicated inhalation procedures have created confusion among patients, affecting their correct understanding of inhalation. Recent studies reported that up to 80% of patients made technical errors in inhalation and emphasized the necessity for patient education. OBJECTIVE: We aimed to assess the importance of inhalation-related instructions and to find clinical factors associated with improvements in the inhalation technique. METHODS: We conducted a retrospective, single-center study at a regional core hospital in Japan. Physicians and community pharmacists constructed an interactive instruction system and shared a common inhalation procedure manual. Patients who received instructions for the inhalation technique at least 3 times were recruited. RESULTS: A total of 125 patients were analyzed in this study. The median age was 73 years (interquartile range, 67-80 years). At the second visit, 67 patients (53.6%) failed to correctly perform the technique despite being guided at the first visit. At the third visit, 48.8% of patients made some errors. After excluding 40 patients who were not subjected to analysis, the remaining 85 were divided into "improvement" and "no-improvement" groups. The total improvement rate was 57.6%. The median time interval between consecutive instructions in the "improvement" groups was 84 days, whereas that in the "no-improvement" group was 128 days (p < 0.05, U test). No significant difference in the age, sex, or primary disease was seen between these groups. CONCLUSION: Repetitive instructions at shorter intervals may be helpful for patients to develop and maintain an improved inhalation technique.
ABSTRACT
Reverse transcription-quantitative PCR (RT-qPCR)-based tests are widely used to diagnose coronavirus disease 2019 (COVID-19). As a result that these tests cannot be done in local clinics where RT-qPCR testing capability is lacking, rapid antigen tests (RATs) for COVID-19 based on lateral flow immunoassays are used for rapid diagnosis. However, their sensitivity compared with each other and with RT-qPCR and infectious virus isolation has not been examined. Here, we compared the sensitivity among four RATs by using severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolates and several types of COVID-19 patient specimens and compared their sensitivity with that of RT-qPCR and infectious virus isolation. Although the RATs read the samples containing large amounts of virus as positive, even the most sensitive RAT read the samples containing small amounts of virus as negative. Moreover, all RATs tested failed to detect viral antigens in several specimens from which the virus was isolated. The current RATs will likely miss some COVID-19 patients who are shedding infectious SARS-CoV-2.
Subject(s)
Antigens, Viral/analysis , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Point-of-Care Systems , SARS-CoV-2/isolation & purification , False Negative Reactions , Humans , Immunoassay , Real-Time Polymerase Chain Reaction , SARS-CoV-2/immunology , Sensitivity and Specificity , Specimen HandlingABSTRACT
For single-cell experiments, it is important to accurately count the number of viable cells in a nanoliter well. We used a deep learning-based convolutional neural network (CNN) on a large amount of digital data obtained as microscopic images. The training set consisted of 103 019 samples, each representing a microscopic grayscale image. After extensive training, the CNN was able to classify the samples into four categories, i.e., 0, 1, 2, and more than 2 cells per well, with an accuracy of 98.3% when compared to determination by two trained technicians. By analyzing the samples for which judgments were discordant, we found that the judgment by technicians was relatively correct although cell counting was often difficult by the images of discordant samples. Based on the results, the system was further enhanced by introducing a new algorithm in which the highest outputs from CNN were used, increasing the accuracy to higher than 99%. Our system was able to classify the data even from wells with a different shape. No other tested machine learning algorithm showed a performance higher than that of our system. The presented CNN system is expected to be useful for various single-cell experiments, and for high-throughput and high-content screening.