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4.
HLA ; 100(1): 52-58, 2022 07.
Article in English | MEDLINE | ID: covidwho-1816658

ABSTRACT

The effects of COVID-19 vaccination on alloimmunization and clinical impact in transplant candidates remain largely unknown. In a 61-year-old man who had no donor-specific antibodies (DSA) and was planned to undergo ABO-incompatible kidney transplantation (ABOi KT), DSAs (anti-A24, anti-B51, and anti-Cw14) developed after COVID-19 vaccination. After desensitization therapy, antibody level was further increased, leading to flow cytometric crossmatch-positive status. Donor-specific T cell immunity using interferon-gamma ELISPOT was continuously negative, whereas SARS-CoV-2 specific T cell immunity was intact. After confirming the C1q-negative status of DSA, the patient received ABOi KT. The patient had stable graft function and suppressed alloimmunity up to 2 months after KT. COVID-19 vaccination might relate to alloimmunization in transplant candidates, and desensitization through immune monitoring can help guide transplantation.


Subject(s)
COVID-19 , Kidney Transplantation , Alleles , Antibodies , COVID-19 Vaccines , Flow Cytometry , Graft Rejection , Graft Survival , HLA Antigens , Humans , Living Donors , Male , Middle Aged , SARS-CoV-2 , Vaccination
5.
Microbiol Spectr ; 10(1): e0161421, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1691406

ABSTRACT

The antigen-based rapid diagnostic test (Ag-RDT) using saliva specimens is fast, noninvasive, and suitable for SARS-CoV-2 self-testing, unlike nasopharyngeal swab (NPS) testing. We evaluated a novel Beanguard gargle (BG)-based virus collection method that can be applied to Ag-RDT as an alternative to the current RT-PCR with an NPS for early diagnosis of COVID-19. This clinical trial comprised 102 COVID-19-positive patients hospitalized after a governmental screening process and 100 healthy individuals. Paired NPS and BG-based saliva specimens from COVID-19 patients and healthy individuals were analyzed using NPS-RT-PCR, BG-RT-PCR, and BG-Ag-RDTs, whose diagnostic performance for detecting SARS-CoV-2 was compared. BG-Ag-RDTs showed high sensitivity (97.8%) and specificity (100%) in 45 patients within 6 days of illness and detected all cases of SARS-CoV-2 Alpha and Delta variants. In 11 asymptomatic active COVID-19 cases, both BG-Ag-RDTs and BG-RT-PCR showed sensitivities and specificities of 100%. Sensitivities of BG-Ag-RDT and BG-RT-PCR toward salivary viral detection were highly concordant, with no discrimination between symptomatic (97.0%), asymptomatic (100%), or SARS-CoV-2 variant (100%) cases. The intermolecular interactions between SARS-CoV-2 spike proteins and truncated canavalin, an active ingredient from the bean extract (BE), were observed in terms of physicochemical properties. The detachment of the SARS-CoV-2 receptor-binding domain from hACE2 increased as the BE concentration increased, allowing the release of the virus from hACE2 for early diagnosis. Using BG-based saliva specimens remarkably enhances the Ag-RDT diagnostic performance as an alternative to NPS and enables noninvasive, rapid, and accurate COVID-19 self-testing and mass screening, supporting efficient COVID-19 management. IMPORTANCE An Ag-RDT is less likely to be accepted as an initial test method for early diagnosis owing to its low sensitivity. However, our self-collection method, Ag-RDT using BG-based saliva specimens, showed significantly enhanced detection sensitivity and specificity toward SARS-CoV-2 including the Alpha and Delta variants in all patients tested within 6 days of illness. The method represents an attractive alternative to nasopharyngeal swabs for the early diagnosis of symptomatic and asymptomatic COVID-19 cases. The evidence suggests that the method could have a potential for mass screening and monitoring of COVID-19 cases.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , Saliva/virology , Adult , Aged , Aged, 80 and over , COVID-19/virology , COVID-19 Nucleic Acid Testing , COVID-19 Serological Testing/instrumentation , Female , Humans , Male , Middle Aged , Nasopharynx/virology , Republic of Korea , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Sensitivity and Specificity , Young Adult
6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-314760

ABSTRACT

Background: Antigen based rapid diagnostic test (Ag-RDT) is faster and applicable for self-testing of SARS-CoV-2. Nasopharyngeal swab (NPS) is not technically feasible for self-testing due to requirement of heath professional and risk of contaminated aerosol during sample collection. Thus, saliva specimen can be appropriate for self-sampling technique required for Ag-RDT. However, the detection of virus by Ag-RDT in saliva could be less sensitive. Therefore, we aimed to evaluate novel Beanguard gargleTM (BG)-based virus collection method that can be applied to antigen-rapid detection test (Ag-RDT) as an alternative to the current RT-PCR with a nasopharyngeal swab (NPS) for early diagnosis of COVID-19. Methods: Paired BG-based saliva and NPS specimens were collected from 102 patients with COVID-19 and 100 healthy subjects. The diagnostic performance of Ag-RDT (BG-Ag-RDT) and RT-PCR (BG-RT-PCR) of BG-based saliva specimens for SARS-CoV-2 detection was compared to NPS-RT-PCR. Physical interactions between the bean extract (BE) in BG and SARS-CoV-2 were evaluated using cryo-electron microscopy (cryo-EM), isothermal titration calorimetry, and ELISA.Findings: BG-Ag-RDTs showed high sensitivity (97·8%) and specificity (100%) in all patients within 6 days of illness associated with the infection of SARS-CoV-2 along with Alpha and Delta variants. Notably, in 11 asymptomatic early-stage cases, both BG-Ag-RDTs and BG-RT-PCR showed excellent performance with sensitivity and specificity of 100%. The interaction between SARS-CoV-2 spike proteins and truncated canavalin, an active ingredient from BE, was shown by calorimetry. The ultrastructural features of SARS-CoV-2 particles coated by BE were well observed in cryo-EM, and the detachment of the receptor binding domain of SARS-CoV-2 from hACE2 was increased with increasing concentration of BE in ELISA, allowing us to apply for releasing the virus from hACE2 in the oral cavity to early diagnosis.Interpretation: BG-based saliva specimens applied to Ag-RDT can be an alternative to NPS-RT-PCR for early diagnosis of COVID-19. The method can facilitate self-testing without trained healthcare workers for mass screening, surveillance, and efficient quarantine.Funding: BIO3S, Inc., Korea Basic Science Institute, and Jeonbuk National University Hospital.Declaration of Interest: DSK received grant support for clinical study from BIO3S, Inc. DK, JK and BV were involved in developing Beanguard gargleTM. All disclosures are unrelated to present clinical study. All other authors declare no competing interests.Ethical Approval: Ethical approval for the study was granted by the Institutional Review Board of Jeonbuk National University Hospital (CUH 2021-04-036-002) and written informed consent statements were obtained from all participants.

7.
Biosens Bioelectron ; 175: 112868, 2021 Mar 01.
Article in English | MEDLINE | ID: covidwho-950132

ABSTRACT

Coronavirus disease 2019 (COVID-19) is a newly emerged human infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In a global pandemic, development of a cheap, rapid, accurate, and easy-to-use diagnostic test is necessary if we are to mount an immediate response to this emerging threat. Here, we report the development of a specific lateral flow immunoassay (LFIA)-based biosensor for COVID-19. We used phage display technology to generate four SARS-CoV-2 nucleocapsid protein (NP)-specific single-chain variable fragment-crystallizable fragment (scFv-Fc) fusion antibodies. The scFv-Fc antibodies bind specifically and with high affinity to the SARS-CoV-2 NP antigen, but not to NPs of other coronaviruses. Using these scFv-Fc antibodies, we screened three diagnostic antibody pairs for use on a cellulose nanobead (CNB)-based LFIA platform. The detection limits of the best scFv-Fc antibody pair, 12H1 as the capture probe and 12H8 as the CNB-conjugated detection probe, were 2 ng antigen protein and 2.5 × 104 pfu cultured virus. This LFIA platform detected only SARS-CoV-2 NP, not NPs from MERS-CoV, SARS-CoV, or influenza H1N1. Thus, we have successfully developed a SARS-CoV-2 NP-specific rapid diagnostic test, which is expected to be a simple and rapid diagnostic test for COVID-19.


Subject(s)
Antigens, Viral/isolation & purification , Biosensing Techniques , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , Antibodies, Viral/blood , Antigens, Viral/immunology , COVID-19/immunology , COVID-19/virology , Humans , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Single-Chain Antibodies/immunology
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