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1.
Open Forum Infectious Diseases ; 9(4):1-10, 2022.
Article in English | Academic Search Complete | ID: covidwho-1806558

ABSTRACT

Background Regdanvimab (CT-P59) is a monoclonal antibody with neutralizing activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We report on part 1 of a 2-part randomized, placebo-controlled, double-blind study for patients with mild-to-moderate coronavirus disease 2019 (COVID-19). Methods Outpatients with mild-to-moderate COVID-19 received a single dose of regdanvimab 40 mg/kg (n  =  100), regdanvimab 80 mg/kg (n  =  103), or placebo (n  =  104). The primary end points were time to negative conversion of SARS-CoV-2 from nasopharyngeal swab based on quantitative reverse transcription polymerase chain reaction (RT-qPCR) up to day 28 and time to clinical recovery up to day 14. Secondary end points included the proportion of patients requiring hospitalization, oxygen therapy, or mortality due to COVID-19. Results Median (95% CI) time to negative conversion of RT-qPCR was 12.8 (9.0–12.9) days with regdanvimab 40 mg/kg, 11.9 (8.9–12.9) days with regdanvimab 80 mg/kg, and 12.9 (12.7–13.9) days with placebo. Median (95% CI) time to clinical recovery was 5.3 (4.0–6.8) days with regdanvimab 40 mg/kg, 6.2 (5.5–7.9) days with regdanvimab 80 mg/kg, and 8.8 (6.8–11.6) days with placebo. The proportion (95% CI) of patients requiring hospitalization or oxygen therapy was lower with regdanvimab 40 mg/kg (4.0% [1.6%–9.8%]) and regdanvimab 80 mg/kg (4.9% [2.1%–10.9%]) vs placebo (8.7% [4.6%–15.6%]). No serious treatment-emergent adverse events or deaths occurred. Conclusions Regdanvimab showed a trend toward a minor decrease in time to negative conversion of RT-qPCR results compared with placebo and reduced the need for hospitalization and oxygen therapy in patients with mild-to-moderate COVID-19. Clinical trial registration.  NCT04602000 and EudraCT 2020-003369-20. [ FROM AUTHOR] Copyright of Open Forum Infectious Diseases is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

2.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-314172

ABSTRACT

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) 1 and often results in fatal pneumonia. 2,3 Despite the worldwide effect of the COVID-19 pandemic, the underlying mechanisms of the fatal viral pneumonia remain elusive. Here, we investigated respiratory specimens, including broncholoalveolar lavage fluids (BALFs) and bloods collected from three confirmed cases of COVID-19 patients with varying degrees of disease severity. Surprisingly, over 35% of cells from BALFs obtained from two pneumonic patients was comprised of eosinophils, while 20% was comprised of lymphocytes. Cytological analysis of sputa and tracheal aspirates from all three patients also revealed that more than 90% of total cells were eosinophils. Infiltration of CD16 + /CD24 + polymorphonuclear cells into lungs, together with elevated NKT cells in BALFs and peripheral blood samples, in patients with severe pneumonia was confirmed by flow cytometry. Moreover, rapid and profound IgE responses against the N protein of SARS-CoV-2 was only detected in plasma from a patient suffering from more severe and prolonged pneumonia. A significant reduction in oxygen demand with improved chest imaging was observed in two severe COVID-19 patients after treatment with a steroid, methylprednisolone. The present study provides evidence that acute eosinophilic pneumonia 4 is associated with COVID-19.

3.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-314171

ABSTRACT

Despite the worldwide effect of the Coronavirus disease 2019 (COVID-19) pandemic, the underlying mechanisms of fatal viral pneumonia remain elusive. Here, we conducted kinetic profiling of respiratory leukocytes and associated inflammatory mediators to show that severe COVID-19 is associated with delayed but enhanced eosinophilic inflammation when compared to mild cases. In addition, we confirmed increased Th2-biased adaptive immune responses, accompanying overt complement activation, in the severe group. Moreover, enhanced antibody responses and complement activation was associated with disease pathogenesis as evidenced by formation of immune complexes and membrane attack complexes in airways and vasculature of lung biopsies from a fatal case, as well as by enhanced hallmark gene set signatures of FcgR signaling and complement activation in myeloid cells of respiratory specimens from severe COVID-19 patients. We also observed expression of viral antigen in lung epithelial and endothelial cells without producing viruses during late stage of COVID-19, indicating abortive viral infection which may further fuel antibody responses and aggravate immune-complex-mediated inflammation. These results suggest that SARS-CoV-2 infection may drive scripted specific innate immune responses, including eosinophilic inflammation, and subsequent pulmonary pathogenesis via enhanced Th2-biased immune responses, which might be crucial drivers of severe pneumonia in COVID-19 patients.

4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-310027

ABSTRACT

CT-P59, a monoclonal antibody with potent neutralizing activity against severe acute respiratory syndrome coronavirus 2, may ameliorate symptoms and prevent hospitalization in outpatients with mild-to-moderate disease. We report findings from part one of a two-part randomized, placebo-controlled, double-blind study (NCT04602000;EudraCT: 2020-003369-20). Outpatients with mild-to-moderate COVID-19 received a single dose of CT-P59 40 mg/kg ( n= 101), CT-P59 80 mg/kg ( n= 103), or placebo ( n= 103). Median (95% confidence interval [CI]) time to conversion to negative RT-qPCR result (coprimary endpoint) was 12.8 days (9.00–12.84) with CT-P59 40 mg/kg, 11.9 days (8.94–12.91) with CT-P59 80 mg/kg, and 12.9 days (12.75–13.99) with placebo. Median (95% CI) time to clinical recovery (coprimary endpoint) was 5.4 days (3.97–6.78) with CT-P59 40 mg/kg, 6.2 days (5.53–7.85) with CT-P59 80 mg/kg, and 8.8 days (6.72–11.73) with placebo. The proportion (95% CI) of patients requiring hospitalization or oxygen therapy was lower with CT-P59 40 mg/kg (4.0% [1.6–9.7%]) and CT-P59 80 mg/kg (4.9% [2.1–10.9%]) versus placebo (8.7% [4.7–15.8%). CT-P59 was well tolerated and no serious treatment-emergent adverse events or deaths occurred. In summary, CT-P59 accelerated viral and clinical recovery from COVID-19 and was well tolerated in patients with mild-to-moderate infection.

5.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-306473

ABSTRACT

Dual-labeled PNA probe used RT-LAMP molecular rapid assay targeting SARS-CoV-2 ORF1ab and N genes was developed, and the analytical, clinical performances for detection of SARS-CoV-2 RNA extracted from clinical nasopharyngeal swab specimens were evaluated in this study. Data showed that this assay is highly specific for SARS-CoV-2, and the absolute detection limit is 1 genomic copy per microliter of viral RNA which can be considered to be comparable to gold-standard molecular diagnostic method real-time reverse transcriptase PCR. Both clinical sensitivity and specificity against a commercial real-time RT-PCR assay were determined as identical. In conclusion, the PNA RT-LAMP assay showed high analytical and clinical accuracy which are identical to real-time RT-PCR which has been routinely used for the detection of SARS-CoV-2.

6.
Arch Virol ; 167(3): 871-879, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1680885

ABSTRACT

Coronavirus disease 2019 (COVID-19) is an acute respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Other coronaviruses (CoVs) can also infect humans, although the majority cause only mild respiratory symptoms. Because early diagnosis of SARS-CoV-2 is critical for preventing further transmission events and improving clinical outcomes, it is important to be able to distinguish SARS-CoV-2 from other SARS-related CoVs in respiratory samples. Therefore, we developed and evaluated a novel reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay targeting the genes encoding the spike (S) and membrane (M) proteins to enable the rapid identification of SARS-CoV-2, including several new circulating variants and other emerging SARS-like CoVs. By analysis of in vitro-transcribed mRNA, we established multiplex RT-qPCR assays capable of detecting 5 × 10° copies/reaction. Using RNA extracted from cell culture supernatants, our multiple simultaneous SARS-CoV-2 assays had a limit of detection of 1 × 10° TCID50/mL and showed no cross-reaction with human CoVs or other respiratory viruses. We also validated our method using human clinical samples from patients with COVID-19 and healthy individuals, including nasal swab and sputum samples. This novel one-step multiplex RT-qPCR assay can be used to improve the laboratory diagnosis of human-pathogenic CoVs, including SARS-CoV-2, and may be useful for the identification of other SARS-like CoVs of zoonotic origin.


Subject(s)
COVID-19 , COVID-19/diagnosis , Clinical Laboratory Techniques , Feasibility Studies , Humans , Real-Time Polymerase Chain Reaction , SARS-CoV-2/genetics , Sensitivity and Specificity
7.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-297000

ABSTRACT

Background Clevudine, an antiviral drug for chronic hepatitis B virus infection, is expected to inhibit the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Therefore, we conducted a prospective, single-blind, proof of concept clinical study to examine the antiviral efficacy and safety of clevudine compared to placebo in Korean corona virus disease 19 (COVID-19) patients with moderate severity. Methods Adults with confirmed SARS-CoV-2 infection and symptom onset within 7 days were randomized 2:1 to 120 mg clevudine or placebo to receive one of treatments orally once-daily for 14 days. Antiviral efficacy outcomes were the proportion of patients with real-time reverse transcription polymerase chain reaction (RT-PCR) negative result for SARS-CoV-2 infection and cycle threshold (Ct) value changes from baseline. Clinical efficacy outcomes included proportion of patients who showed improvement in lung involvement by imaging tests, proportion of patients with normal body temperature, proportion of patients with normal oxygen saturation, and the changes in C-reactive protein (CRP) from baseline. Safety outcomes included changes in clinical laboratory tests, vital signs measurement, and physical examination from baseline, and incidence of adverse events. Results The proportion of patients with real-time RT-PCR negative test and Ct value changes showed no significant difference between clevudine group and placebo group. The changes in Ct value from baseline were significantly greater in clevudine group compared to placebo group in patients with hypertension, and patients who underwent randomization during the first 5 and 7 days after the onset of symptoms. All clinical efficacy outcomes had no significant difference between clevudine group and placebo group. Clevudine was well tolerated and there was no significant difference in safety profile between two treatment groups. Conclusions This is the first clinical study to compare the antiviral efficacy and safety of clevudine to placebo in Korean COVID-19 patients with moderate severity. The study has demonstrated a possible favorable outcome for the reduction of SARS-CoV-2 replication, with acceptable safety profile, when COVID-19 patients were treated with clevudine. Further large-scale clinical studies, preferably with various clinical endpoints and virus titer evaluation, are required to better understand the effectiveness of using clevudine in COVID-19 treatment. Considering recent trend in clinical development for antiviral drugs, we need to design a clinical study aiming for reducing clinical risk of COVID-19 in mild to moderate patients with at least one risk factor for serious illness.

9.
Clin Ther ; 43(10): 1706-1727, 2021 10.
Article in English | MEDLINE | ID: covidwho-1525737

ABSTRACT

PURPOSE: Neutralizing antibodies can reduce SARS-CoV-2 cellular entry, viral titers, and pathologic damage. CT-P59 (regdanvimab), a SARS-CoV-2 neutralizing monoclonal antibody, was examined in 2 randomized, double-blind, placebo-controlled, single ascending dose, Phase I studies. METHODS: In study 1.1, healthy adults were sequentially enrolled to receive CT-P59 10, 20, 40, or 80 mg/kg or placebo. In study 1.2, adult patients with mild SARS-CoV-2 infection were enrolled to receive CT-P59 20, 40, or 80 mg/kg or placebo. Primary objectives of both studies were safety and tolerability up to day 14 after infusion. Secondary end points included pharmacokinetic properties. Study 1.2 also measured virology and clinical efficacy. FINDINGS: Thirty-two individuals were randomized to study 1.1 (6 per CT-P59 dose cohort and 8 in the placebo cohort). By day 14 after infusion, adverse events (AEs) were reported in 2 individuals receiving CT-P59 20 mg/kg (headache and elevated C-reactive protein levels) and 1 receiving CT-P59 40 mg/kg (pyrexia) (all Common Terminology Criteria for Adverse Events grade 1). In study 1.2, 18 patients were randomized (5 per dose cohort and 3 in the placebo cohort). Sixteen AEs were reported in 10 patients receiving CT-P59. No AEs in either study led to study discontinuation. Greater reductions in viral titers were reported with CT-P59 than placebo in those with maximum titers >105 copies/mL. Mean time to recovery was 3.39 versus 5.25 days. IMPLICATIONS: CT-P59 exhibited a promising safety profile in healthy individuals and patients with mild SARS-CoV-2 infection, with potential antiviral and clinical efficacy in patients with mild SARS-CoV-2 infection. ClinicalTrials.gov identifier: NCT04525079 (study 1.1) and NCT04593641 (study 1.2).


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing , Carrier Proteins , Double-Blind Method , Humans , Immunoglobulin G
10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-292354

ABSTRACT

The pandemic coronavirus disease 2019 (COVID-19) is characterized as an acute respiratory infection in the majority of cases and is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, other coronaviruses (CoVs) can infect humans, although the majority only cause mild respiratory symptoms. As early diagnosis of SARS-CoV-2 is critical to prevent further transmission events and to improve clinical outcomes, it is important to be able to distinguish SARS-CoV-2 from other CoVs in respiratory samples. Therefore, we developed and evaluated a novel quantitative reverse transcription PCR (RT-qPCR) assay, targeting the spike (S) and membrane (M) genes, to enable the rapid identification of SARS-CoV-2 including several new circulating variants, and other emerging pan-SARS-like CoVs. Using RNA extracted from cell culture supernatants, our multiple simultaneous SARS-CoV-2 assays confirmed a limit of detection of 1 × 10 0 TCID 50 /ml and no cross-reaction with human coronaviruses or other respiratory viruses. We also validated our method using human clinical samples from COVID-19 patients and healthy individuals, including nasal swab and sputum samples. This novel one-step multiplex RT-qPCR assay can be used to improve the laboratory diagnosis of human-pathogenic coronaviruses, including SARS-CoV-2, and may be useful for the identification of other pan-SARS-like CoVs of zoonotic origin.

11.
Nano Converg ; 8(1): 31, 2021 Oct 18.
Article in English | MEDLINE | ID: covidwho-1477472

ABSTRACT

It is highly important to sensitively measure the abundance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on various surfaces. Here, we present a nucleic acid-based detection method consisting of a new sample preparation protocol that isolates only viruses, not the free RNA fragments already present on the surfaces of indoor human-inhabited environments, using a graphene oxide-coated microbead filter. Wet wipes (100 cm2), not cotton swabs, were used to collect viruses from environmental surfaces with large areas, and viruses were concentrated and separated with a graphene oxide-coated microbead filter. Viral RNA from virus was recovered 88.10 ± 8.03% from the surface and free RNA fragment was removed by 99.75 ± 0.19% from the final eluted solution. When we tested the developed method under laboratory conditions, a 10-fold higher viral detection sensitivity (Detection limit: 1 pfu/100 cm2) than the current commercial protocol was observed. Using our new sample preparation protocol, we also confirmed that the virus was effectively removed from surfaces after chemical disinfection; we were unable to measure the disinfection efficiency using the current commercial protocol because it cannot distinguish between viral RNA and free RNA fragments. Finally, we investigated the presence of SARS-CoV-2 and bacteria in 12 individual negative pressure wards in which patients with SARS-CoV-2 infection had been hospitalized. Bacteria (based on 16 S DNA) were found in all samples collected from patient rooms; however, SARS-CoV-2 was mainly detected in rooms shared by two patients.

12.
Sci Rep ; 11(1): 20471, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1469980

ABSTRACT

Dual-labeled PNA probe used RT-LAMP molecular rapid assay targeting SARS-CoV-2 ORF1ab and N genes was developed, and the analytical, clinical performances for detection of SARS-CoV-2 RNA extracted from clinical nasopharyngeal swab specimens were evaluated in this study. Data showed that this assay is highly specific for SARS-CoV-2, and the absolute detection limit is 1 genomic copy per microliter of viral RNA which can be considered to be comparable to gold-standard molecular diagnostic method real-time reverse transcriptase PCR. Both clinical sensitivity and specificity against a commercial real-time RT-PCR assay were determined as identical. In conclusion, the PNA RT-LAMP assay showed high analytical and clinical accuracy which are identical to real-time RT-PCR which has been routinely used for the detection of SARS-CoV-2.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , RNA, Viral/analysis , SARS-CoV-2/isolation & purification , Coronavirus Nucleocapsid Proteins/genetics , Genes, Viral , Humans , Limit of Detection , Phosphoproteins/genetics , Polyproteins/genetics , RNA, Viral/genetics , SARS-CoV-2/genetics , Sensitivity and Specificity , Viral Proteins/genetics
13.
Korean J Intern Med ; 37(1): 201-209, 2022 01.
Article in English | MEDLINE | ID: covidwho-1441243

ABSTRACT

BACKGROUND/AIMS: Coronavirus disease 2019 (COVID-19) is associated with acute respiratory syndrome. The mechanisms underlying the different degrees of pneumonia severity in patients with COVID-19 remain elusive. This study provides evidence that COVID-19 is associated with eosinophil-mediated inflammation. METHODS: We performed a retrospective case series of three patients with laboratory and radiologically confirmed COVID-19 pneumonia admitted to Chosun University Hospital. Demographic and clinical data on inflammatory cell lung infiltration and cytokine levels in patients with COVID-19 were collected. RESULTS: Cytological analysis of sputum, tracheal aspirates, and bronchoalveolar lavage fluid (BALF) samples from all three patients revealed massive infiltration of polymorphonuclear cells (PMNs), such as eosinophils and neutrophils. All sputum and BALF specimens contained high levels of eosinophil cationic proteins. The infiltration of PMNs into the lungs, together with elevated levels of natural killer T (NKT) cells in BALF and peripheral blood samples from patients with severe pneumonia in the acute phase was confirmed by flow cytometry. CONCLUSION: These results suggest that the lungs of COVID-19 patients can exhibit eosinophil-mediated inflammation, together with an elevated NKT cell response, which is associated with COVID-19 pneumonia.


Subject(s)
COVID-19 , Natural Killer T-Cells , Pulmonary Eosinophilia , Bronchoalveolar Lavage Fluid , Eosinophils , Humans , Pulmonary Eosinophilia/diagnosis , Retrospective Studies , SARS-CoV-2
14.
Clin Ther ; 43(10): 1706-1727, 2021 10.
Article in English | MEDLINE | ID: covidwho-1433085

ABSTRACT

PURPOSE: Neutralizing antibodies can reduce SARS-CoV-2 cellular entry, viral titers, and pathologic damage. CT-P59 (regdanvimab), a SARS-CoV-2 neutralizing monoclonal antibody, was examined in 2 randomized, double-blind, placebo-controlled, single ascending dose, Phase I studies. METHODS: In study 1.1, healthy adults were sequentially enrolled to receive CT-P59 10, 20, 40, or 80 mg/kg or placebo. In study 1.2, adult patients with mild SARS-CoV-2 infection were enrolled to receive CT-P59 20, 40, or 80 mg/kg or placebo. Primary objectives of both studies were safety and tolerability up to day 14 after infusion. Secondary end points included pharmacokinetic properties. Study 1.2 also measured virology and clinical efficacy. FINDINGS: Thirty-two individuals were randomized to study 1.1 (6 per CT-P59 dose cohort and 8 in the placebo cohort). By day 14 after infusion, adverse events (AEs) were reported in 2 individuals receiving CT-P59 20 mg/kg (headache and elevated C-reactive protein levels) and 1 receiving CT-P59 40 mg/kg (pyrexia) (all Common Terminology Criteria for Adverse Events grade 1). In study 1.2, 18 patients were randomized (5 per dose cohort and 3 in the placebo cohort). Sixteen AEs were reported in 10 patients receiving CT-P59. No AEs in either study led to study discontinuation. Greater reductions in viral titers were reported with CT-P59 than placebo in those with maximum titers >105 copies/mL. Mean time to recovery was 3.39 versus 5.25 days. IMPLICATIONS: CT-P59 exhibited a promising safety profile in healthy individuals and patients with mild SARS-CoV-2 infection, with potential antiviral and clinical efficacy in patients with mild SARS-CoV-2 infection. ClinicalTrials.gov identifier: NCT04525079 (study 1.1) and NCT04593641 (study 1.2).


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Humanized , Antibodies, Neutralizing , Carrier Proteins , Double-Blind Method , Humans , Immunoglobulin G
15.
Cell Rep ; 37(1): 109798, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1415262

ABSTRACT

Despite the worldwide effect of the coronavirus disease 2019 (COVID-19) pandemic, the underlying mechanisms of fatal viral pneumonia remain elusive. Here, we show that critical COVID-19 is associated with enhanced eosinophil-mediated inflammation when compared to non-critical cases. In addition, we confirm increased T helper (Th)2-biased adaptive immune responses, accompanying overt complement activation, in the critical group. Moreover, enhanced antibody responses and complement activation are associated with disease pathogenesis as evidenced by formation of immune complexes and membrane attack complexes in airways and vasculature of lung biopsies from six fatal cases, as well as by enhanced hallmark gene set signatures of Fcγ receptor (FcγR) signaling and complement activation in myeloid cells of respiratory specimens from critical COVID-19 patients. These results suggest that SARS-CoV-2 infection may drive specific innate immune responses, including eosinophil-mediated inflammation, and subsequent pulmonary pathogenesis via enhanced Th2-biased immune responses, which might be crucial drivers of critical disease in COVID-19 patients.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , Complement System Proteins/immunology , Eosinophils/immunology , Inflammation/immunology , Pneumonia, Viral/immunology , SARS-CoV-2/immunology , Adaptive Immunity , Adult , Aged , Aged, 80 and over , Antigen-Antibody Complex/metabolism , COVID-19/metabolism , COVID-19/virology , Complement Activation , Complement Membrane Attack Complex/metabolism , Eosinophils/virology , Female , Humans , Inflammation/metabolism , Inflammation/virology , Lung Injury/immunology , Lung Injury/pathology , Lung Injury/virology , Male , Middle Aged , Pneumonia, Viral/metabolism , Receptors, IgG/immunology , Receptors, IgG/metabolism , Severity of Illness Index , Signal Transduction , Th2 Cells/immunology , Viral Load , Young Adult
16.
Clin Infect Dis ; 73(3): e550-e558, 2021 08 02.
Article in English | MEDLINE | ID: covidwho-1338090

ABSTRACT

BACKGROUND: Zoonotic coronaviruses have emerged as a global threat by causing fatal respiratory infections. Given the lack of specific antiviral therapies, application of human convalescent plasma retaining neutralizing activity could be a viable therapeutic option that can bridges this gap. METHODS: We traced antibody responses and memory B cells in peripheral blood collected from 70 recovered Middle East respiratory syndrome coronavirus (MERS-CoV) patients for 3 years after the 2015 outbreak in South Korea. We also used a mouse infection model to examine whether the neutralizing activity of collected sera could provide therapeutic benefit in vivo upon lethal MERS-CoV challenge. RESULTS: Anti-spike-specific IgG responses, including neutralizing activity and antibody-secreting memory B cells, persisted for up to 3 years, especially in MERS patients who suffered from severe pneumonia. Mean antibody titers gradually decreased annually by less than 2-fold. Levels of antibody responses were significantly correlated with fever duration, viral shedding periods, and maximum viral loads observed during infection periods. In a transgenic mice model challenged with lethal doses of MERS-CoV, a significant reduction in viral loads and enhanced survival was observed when therapeutically treated with human plasma retaining a high neutralizing titer (> 1/5000). However, this failed to reduce pulmonary pathogenesis, as revealed by pathological changes in lungs and initial weight loss. CONCLUSIONS: High titers of neutralizing activity are required for suppressive effect on the viral replication but may not be sufficient to reduce inflammatory lesions upon fatal infection. Therefore, immune sera with high neutralizing activity must be carefully selected for plasma therapy of zoonotic coronavirus infection.


Subject(s)
Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Animals , Antibodies, Neutralizing , Antibodies, Viral , Coronavirus Infections/drug therapy , Humans , Mice , Republic of Korea , Spike Glycoprotein, Coronavirus
17.
Front Microbiol ; 12: 712260, 2021.
Article in English | MEDLINE | ID: covidwho-1346410

ABSTRACT

Despite a clear association of patient's age with COVID-19 severity, there has been conflicting data on the association of viral load with disease severity. Here, we investigated the association of viral load dynamics with patient's age and severity of COVID-19 using a set of respiratory specimens longitudinally collected (mean: 4.8 times/patient) from 64 patients with broad distribution of clinical severity and age during acute phase. Higher viral burden was positively associated with inflammatory responses, as assessed by IL-6, C-reactive protein, and lactate dehydrogenase levels in patients' plasma collected on the same day, primarily in the younger cohort (≤59 years old) and in mild cases of all ages, whereas these were barely detectable in elderly patients (≥60 years old) with critical disease. In addition, viral load dynamics in elderly patients were not significantly different between mild and critical cases, even though more enhanced inflammation was consistently observed in the elderly group when compared to the younger group during the acute phase of infection. The positive correlation of viral load with disease severity in younger patients may explain the increased therapeutic responsiveness to current antiviral drugs and neutralizing antibody therapies in younger patients compared to elderly patients. More careful intervention against aging-associated inflammation might be required to mitigate severe disease progression and reduce fatality in COVID-19 patients more than 60 years old.

18.
J Allergy Clin Immunol ; 148(4): 996-1006.e18, 2021 10.
Article in English | MEDLINE | ID: covidwho-1330917

ABSTRACT

BACKGROUND: Our understanding of adaptive immune responses in patients with coronavirus disease 2019 (COVID-19) is rapidly evolving, but information on the innate immune responses by natural killer (NK) cells is still insufficient. OBJECTIVE: We aimed to examine the phenotypic and functional status of NK cells and their changes during the course of mild and severe COVID-19. METHODS: We performed RNA sequencing and flow cytometric analysis of NK cells from patients with mild and severe COVID-19 at multiple time points in the course of the disease using cryopreserved PBMCs. RESULTS: In RNA-sequencing analysis, the NK cells exhibited distinctive features compared with healthy donors, with significant enrichment of proinflammatory cytokine-mediated signaling pathways. Intriguingly, we found that the unconventional CD56dimCD16neg NK-cell population expanded in cryopreserved PBMCs from patients with COVID-19 regardless of disease severity, accompanied by decreased NK-cell cytotoxicity. The NK-cell population was rapidly normalized alongside the disappearance of unconventional CD56dimCD16neg NK cells and the recovery of NK-cell cytotoxicity in patients with mild COVID-19, but this occurred slowly in patients with severe COVID-19. CONCLUSIONS: The current longitudinal study provides a deep understanding of the NK-cell biology in COVID-19.


Subject(s)
COVID-19/immunology , Killer Cells, Natural/immunology , Lymphocyte Activation , SARS-CoV-2/immunology , Adult , COVID-19/pathology , Humans , Killer Cells, Natural/pathology , Longitudinal Studies , Male , Middle Aged , Prospective Studies , RNA-Seq
19.
Clin Microbiol Infect ; 28(2): 292-296, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1312375

ABSTRACT

OBJECTIVES: We aimed to assess the longevity of spike-specific antibody responses and neutralizing activity in the plasma of recovered Middle East respiratory syndrome (MERS) patients. METHODS: We traced the antibody responses and neutralizing activity against MERS coronavirus (MERS-CoV) in peripheral blood samples collected from 70 recovered MERS patients for 5 years after the 2015 MERS outbreak in South Korea. We also measured the half-life of neutralizing antibody titres in the longitudinal specimens. RESULTS: The seropositivity rate persisted for up to 4 years (50.7-56.1%), especially in MERS patients who suffered from severe pneumonia, and then decreased (35.9%) in the fifth year. Although the spike-specific antibody responses decreased gradually, the neutralizing antibody titres decreased more rapidly (half-life: 20 months) in 19 participants without showing negative seroconversion during the study period. Only five (26.3%) participants had neutralizing antibody titres greater than 1/1000 of PRNT50, and a high neutralizing antibody titre over 1/5000 was not detected in the participants at five years after infection. DISCUSSION: The seropositivity rate of the recovered MERS patients persisted up to 4 years after infection and significantly dropped in the fifth year, whereas the neutralizing antibody titres against MERS-CoV decreased more rapidly and were significantly reduced at 4 years after infection.


Subject(s)
Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Antibodies, Neutralizing , Antibodies, Viral , Coronavirus Infections/epidemiology , Follow-Up Studies , Humans , Spike Glycoprotein, Coronavirus
20.
Infect Chemother ; 53(1): 118-127, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1200183

ABSTRACT

BACKGROUND: A pooling test is a useful tool for mass screening of coronavirus disease 2019 (COVID-19) in the pandemic era. We aimed to optimize a simple two-step pooling test by estimating the optimal pool size using experimental and mathematical validation. MATERIALS AND METHODS: Experimental pools were created by mixing one positive respiratory sample with various numbers of negative samples. We selected positive samples with cycle threshold (Ct) values greater than 32 to validate the efficiency of the pooling test assuming a high likelihood of false-negative results due to low viral loads. The positivities of the experimental pools were investigated with a single reverse-transcription polymerase chain reaction (RT-PCR) using the U-TOP™ COVID-19 Detection Kit Plus (Seasun Biomaterials, Daejeon, Korea). We used the Dorfman equation to calculate the optimal size of a pooling test mathematically. RESULTS: Viral RNA could be detected in a pool with a size up to 11, even if the Ct value of a positive sample was about 35. The Dorfman equation showed that the optimal number of samples in a pool was 11 when the prevalence was assumed to be 0.66% based on the test positivity in Daejeon, Korea from April 1, 2020 to November 10, 2020. The efficiency of the pooling test was 6.2, which can save 83.9 of 100 individual tests. CONCLUSION: Eleven samples in a pool were validated optimal experimentally assuming a prevalence of 0.66%. The pool size needs modification as the pandemic progresses; thus, the prevalence should be carefully estimated before pooling tests are conducted.

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