scholarly journals Preexisting vs. de novo antibodies against SARS-CoV-2 in individuals without or with virus infection: impact on antibody therapy, vaccine research and serological testing

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kar Muthumani ◽  
Ziyang Xu ◽  
Moonsup Jeong ◽  
Joel N. Maslow ◽  
Vaniambadi S. Kalyanaraman ◽  
...  
Keyword(s):  
Immune Responses ◽  
De Novo ◽  
Antibody Therapy ◽  
Serological Testing ◽  
Healthy Individuals ◽  
Rt Pcr ◽  
Vaccine Research ◽  
Serological Tests ◽  
Nucleocapsid Proteins ◽  
Pcr Method

AbstractThe causative agent of the ongoing pandemic in the world is SARS-CoV-2. The research on SARS-CoV-2 has progressed with lightning speed on various fronts, including clinical research and treatment, virology, epidemiology, drug development, and vaccine research. Recent studies reported that sera from healthy individuals, who were confirmed negative for SARS-CoV-2 by RT-PCR method, tested positive for antibodies against spike and nucleocapsid proteins of SARS-CoV-2. Further, such antibodies also exhibited neutralizing activity against the virus. These observations have prompted us to prepare a commentary on this topic. While the preexisting antibodies are likely to protect against SARS-CoV-2 infection, they may also complicate serological testing results. Another unknown is the influence of preexisting antibodies on immune responses in individuals receiving vaccines against  SARS-CoV-2. The commentary identifies the potential limitations with the serological tests based on spike and nucleocapsid proteins as these tests may overestimate the seroprevalence due to cross-reactive antibodies. The inclusion of tests specific to SARS-CoV-2 (such as RBD of spike protein) could overcome these limitations.

scholarly journals COVID-19 serological testing for Healthcare Workers in Lombardy, Italy

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
G Del Castillo ◽  
A Castrofino ◽  
F Grosso ◽  
A Barone ◽  
L Crottogini ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Geographical Area ◽  
Healthcare Facility ◽  
Nasopharyngeal Swab ◽  
Infection Prevalence ◽  
Serological Testing ◽  
Prevention Policy ◽  
Rt Pcr ◽  
Serological Tests ◽  
Screening Process

Abstract Issue COVID-19 pandemic began in Italy on February 20th, 2020. Since the beginning of the emergency Healthcare Workers' (HCWs) involvement was prominent, mainly due to direct assistance to COVID-19 patients. Therefore, we implemented a prevention policy for HCW screening through serological and RT-PCR testing. Description of the problem HCW screening for SARS-CoV-2 infection is essential for prevention and control of the pandemic. Lombardy's Healthcare authorities settled a screening process for HCWs divided into three steps: 1) body temperature assessment at the beginning and the end of work shift, if fever > 37.5 °C was present the HCW was sent back home and a nasopharyngeal swab was performed; 2) progressive recruitment for serological testing; 3) on those positive to IgG a nasopharyngeal swab was performed and tested for viral RNA by RT-PCR. Results Among 79185 HCW tested, 9589 (12%) were positive on serological IgG testing. Of the 9589 positive a nasopharyngeal swab was performed on 6884. Of these 358 (5%) tested positive and the remaining 6526 (95%) negative to RT-PCR. We calculated a Positive Predictive Value of 5.2%. The rate of positive serological tests for each Healthcare facility varied between 0% and 78%. Five percent of all facilities, belonging to Brescia, Bergamo and Cremona area, reported a positivity rate higher than 40% in HCWs. A second cluster (18% of all facilities), involving the same geographical area, reported a rate between 20% and 40%, whereas the remaining facilities (76%) of the region a rate <20%. Lessons Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs especially in a high infection prevalence setting. Key messages Serological IgG testing can be, if followed by immediate nasopharyngeal swab testing, a valid screening intervention on asymptomatic HCWs. Infection prevention in HCW may benefit from a screening campaign especially in high prevalence settings.

scholarly journals A Low-Cost SARS-CoV-2 rRBD ELISA to Detect Serostatus in Ecuadorian Population with COVID-19

2021 ◽  
Vol 104 (4) ◽  
pp. 1513-1515 ◽  
Author(s):  
Ángel Guevara ◽  
Sandra Vivero ◽  
Victoria Nipaz ◽  
Victor Guaraca ◽  
Josefina Coloma
Keyword(s):  
Immune Responses ◽  
Predictive Value ◽  
Intestinal Parasites ◽  
Low Cost ◽  
Laboratory Diagnosis ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Serological Tests ◽  
Simple Alternative ◽  
Sensitivity Specificity

ABSTRACTLaboratory diagnosis of the COVID-19 relies on RT-PCR to amplify specific fragments of SARS-CoV-2 genome. However, serological tests are required to determine the immune response elicited after infection. Here, we analyzed convalescent sera collected from positive individuals by RT-PCR to SARS-CoV-2 (n = 78), Zika (n = 20), dengue (n = 20), chikungunya (n = 54), intestinal parasites (n = 11), and HIV (n = 1), from different areas of Ecuador, with an in-house ELISA using a SARS-CoV-2 receptor binding domain recombinant (rRBD) antigen to detect IgG antibodies elicited by SARS-CoV-2 infection. Of the 78 samples positive for SARS-CoV-2 by RT-PCR, 73 showed high absorbance value compared with the cutoff and five were negative. All tested sera from other infections showed no reactivity. Sensitivity, specificity, positive predictive value, and negative predictive value were 93.6%, 100%, 100%, and 95.4%, respectively. This in-house anti-IgG rRBD ELISA offers an economic and simple alternative to determine IgG immune responses after SARS-CoV-2 infection.

scholarly journals The Consistency between Covid-19 RT-PCR and IgM/IgG Quick tests results

2021 ◽  
Vol 26 (2) ◽  
pp. 2560-2565
Author(s):  
IRINA-ANCA EREMIA ◽  
◽  
ADRIANA BIDICĂ ◽  
REMUS-IULIAN NICA ◽  
EUGEN RADU ◽  
...  
Keyword(s):  
Abdominal Pain ◽  
Retrospective Study ◽  
Signs And Symptoms ◽  
High Volume ◽  
Serological Testing ◽  
Rt Pcr ◽  
Serological Tests ◽  
Emergency Hospital ◽  
Serologic Tests

The aim of this retrospective study was to analyze the results of tests for SARSCoV-2 performed during 07.04.2020- 20.06.2020 in the Department of the Emergency from Bucharest University Emergency Hospital. We detected 173 men and 133 women that were tested with both RT-PCR and serologic tests. The results were concordant for 287 samples (93,8%) that were collected from subjects for whom the diagnosis of COVID-19 was subsequently confirmed (10) or infirmed (277). We found that the most frequent signs and symptoms of patients with COVID-19 were at the respiratory (e.g. dyspnea), neurological (e.g. vertigo, cephalgia) and gastrointestinal (e.g. abdominal pain, vomiting, high volume of the abdomen) systems. There was no situation with positive RT-PCR and IgG and negative IgM results. In our study the RT-PCR and quick serological tests were concordant in 93,8% of cases. The combination of RT-PCR and serological testing can enhance the accuracy of COVID-19 diagnosis.

scholarly journals Optimising triage procedures for patients with cancer needing active anticancer treatment in the COVID-19 era

ESMO Open ◽  
2020 ◽  
Vol 5 (5) ◽  
pp. e000885
Author(s):  
Grazia Arpino ◽  
Carmine De Angelis ◽  
Pietro De Placido ◽  
Erica Pietroluongo ◽  
Luigi Formisano ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Asymptomatic Patient ◽  
Serological Test ◽  
University Hospital ◽  
Serological Testing ◽  
Rt Pcr ◽  
Serological Tests ◽  
Patients With Cancer ◽  
Anticancer Treatment ◽  
Active Cancer

BackgroundImmunosuppression induced by anticancer therapy in a COVID-19-positive asymptomatic patient with cancer may have a devastating effect and, eventually, be lethal. To identify asymptomatic cases among patients receiving active cancer treatment, the Federico II University Hospital in Naples performs rapid serological tests in addition to hospital standard clinical triage for COVID-19 infection.MethodsFrom 6 to 17 April 2020, all candidates for chemotherapy, radiotherapy or target/immunotherapy, if negative at the standard clinical triage on the day scheduled for anticancer treatment, received a rapid serological test on peripheral blood for COVID-19 IgM and IgG detection. In case of COVID-19 IgM and/or IgG positivity, patients underwent a real-time PCR (RT-PCR) SARS-CoV-2 test to confirm infection, and active cancer treatment was delayed.ResultsOverall 466 patients, negative for COVID-19 symptoms, underwent serological testing in addition to standard clinical triage. The average age was 61 years (range 25–88 years). Most patients (190, 40.8%) had breast cancer, and chemotherapy with or without immunotherapy was administered in 323 (69.3%) patients. Overall 433 (92.9%) patients were IgG-negative and IgM-negative, and 33 (7.1%) were IgM-positive and/or IgG-positive. Among the latter patients, 18 (3.9%), 11 (2.4%) and 4 (0.9%) were IgM-negative/IgG-positive, IgM-positive/IgG-negative and IgM-positive/IgG-positive, respectively. All 33 patients with a positive serological test, tested negative for RT-PCR SARS-CoV-2 test. No patient in our cohort developed symptoms suggestive of active COVID-19 infection.ConclusionRapid serological testing at hospital admission failed to detect active asymptomatic COVID-19 infection. Moreover, it entailed additional economic and human resources, delayed therapy administrationand increased hospital accesses.

scholarly journals Clinical validation and performance evaluation of the automated Vitros Total Anti-SARS-CoV-2 Antibodies assay for screening of serostatus in COVID-19

2020 ◽  
Author(s):  
Emily Garnett ◽  
Joanna Jung ◽  
Estella Tam ◽  
Deepthi Rajapakshe ◽  
Stephen Cheney ◽  
...  
Keyword(s):  
Viral Infections ◽  
Acute Infection ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Medical Professional ◽  
List Type ◽  
Serological Testing ◽  
Rt Pcr ◽  
Serological Tests ◽  
Few Data

AbstractObjectivesEvaluation of serostatus against SARS-CoV-2 has emerged as an important tool in identification of exposure to COVID-19. We report on the validation of the Vitros Anti-SARS-CoV-2 Total (CoV2T) assay for qualitative serological testing of SARS-CoV-2 antibodies.MethodsWe performed validation studies according to COLA guidelines, using samples previously tested for SARS-CoV-2 by RT-PCR. We evaluated precision, analytical interferences, and cross-reactivity with other viral infections. We also evaluated concordance with molecular and other serological testing, and evaluated seroconversion.ResultsThe Vitros CoV2T assay exhibited acceptable precision, was resistant to analytical interference, and did not exhibit cross-reactivity with samples positive for other respiratory viruses. The CoV2T assay exhibited 100% negative predictive agreement (56/56) and 71% positive predictive agreement (56/79) with RT-PCR across all patient samples, and was concordant with other serological assays. Concordance with RT-PCR was 97% > 7 days after symptom onset.ConclusionsThe Vitros CoV2T assay was successfully validated in our laboratory. We anticipate it will be a useful tool in screening for exposure to SARS-CoV-2, however, the use of the CoV2T and other serological assays in clinical management of COVID-19 patients is yet unknown, and must be evaluated in future studies.Key pointsWhat issue or core problem does the study address?Multiple serological assays for detection of anti-SARS-CoV-2 antibodies have received FDA Emergency Use Authorizations, but few data have been published on the performance of these assays.What would one take-home point for the working medical professional be?The Vitros Anti-SARS-CoV-2 Total assay is a total antibody test to be used as a serological screen for exposure to COVID-19. This assay performs well, and is comparable to other serological tests.What is the most significant or most interesting finding of the study?We confirmed that the Vitros Anti-SARS-CoV-2 Total assay, like other serological tests, is not suitable for diagnosis of acute infection, as it is not sensitive to infection <7 days post-onset.

Genexpressionsmuster von fibrinolytischen Faktoren des Urokinase-Plasmin-Systems bei Dermatoliposklerose

Phlebologie ◽  
1999 ◽  
Vol 28 (01) ◽  
pp. 1-6 ◽  
Author(s):  
Ch. Stetter ◽  
E. Schöpf ◽  
J. Norgauer ◽  
W. Vanscheidt ◽  
Y. Herouy
Keyword(s):  
Mrna Expression ◽  
De Novo ◽  
Ulcus Cruris ◽  
Ulcus Cruris Venosum ◽  
Rt Pcr ◽  
Fand Sich ◽  
Pai 1

ZusammenfassungDie Dermatoliposklerose (DLS) entwickelt sich als Folge einer progredienten primären Varikosis oder eines postthrombotischen Syndroms (PTS). Trotz bestehender Hinweise auf eine veränderte intravasale fibrinolytische Aktivität bei der chronisch-venösen Insuffizienz (CVI), wurden bisher fibrinolytische Faktoren im perivaskulären Gewebe nicht untersucht. Kürzlich zeigten wir, daß bei Dermatoliposklerose Matrix-Metalloproteinasen exprimiert und aktiviert werden. Da spezifische fibrinolytische Faktoren wichtige Haupteffektoren der Matrix-Metalloproteinasenaktivierung sind, untersuchten wir kürzlich die Genexpression der Plasminogenaktivatoren vom Urokinasetyp (uPA) und vom Gewebetyp (tPA), des Urokinase-Rezeptor (uPA-R) sowie der Plasminogenaktivator-Inhibitoren (PAI-1 und PAI-2) in Gewebsbiopsien von Patienten mit Dermatoliposklerose. Zum Nachweis verwandten wir dabei die Technik der reversen Transkription und Polymerase-Kettenreaktion (RT-PCR). Es fand sich in allen Hautproben (n = 21) eine signifikant erhöhte mRNA-Expression von uPA und uPA-R im Vergleich zu gesunder Haut (n = 12). Dagegen konnte kein signifikanter Unterschied für mRNA-Transkripte von tPA, PAI-1 und PAI-2 nachgewiesen werden. Die Dermatoliposklerose zeichnet sich somit durch erhöhte transkriptionelle Expression von uPA und uPA-R aus. Eine gesteigerte De-novo-Synthese von uPA und uPA-R könnte daher bei der Aktivierung von Matrix-Metalloproteinasen und entsprechend in der Pathogenese des Ulcus cruris venosum eine zentrale Rolle spielen.

scholarly journals Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in COVID-19 patients and healthy individuals

2021 ◽  
pp. eabd6990
Author(s):  
Sang Il Kim ◽  
Jinsung Noh ◽  
Sujeong Kim ◽  
Younggeun Choi ◽  
Duck Kyun Yoo ◽  
...  
Keyword(s):  
B Cells ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Binding Domain ◽  
Host Cells ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Healthy Individuals

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 out of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were comprised of immunoglobulin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobulin heavy joining (IGHJ)6 genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different immunoglobulin heavy variable chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in six out of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

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