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1.
Clin Chem Lab Med ; 2022 Mar 17.
Article in English | MEDLINE | ID: covidwho-1753223

ABSTRACT

OBJECTIVES: Evaluating anti-SARS-CoV-2 antibody levels is a current priority to drive immunization, as well as to predict when a vaccine booster dose may be required and for which priority groups. The aim of our study was to investigate the kinetics of anti-SARS-CoV-2 Spike S1 protein IgG (anti-S1 IgG) antibodies and neutralizing antibodies (NAbs) in an Italian cohort of healthcare workers (HCWs), following the Pfizer/BNT162b2 mRNA vaccine, over a period of up to six months after the second dose. METHODS: We enrolled 57 HCWs, without clinical history of COVID-19 infection. Fluoroenzyme-immunoassay was used for the quantitative anti-S1 IgG antibodies at different time points T1 (one month), T3 (three months) and T6 (six months) following the second vaccine shot. Simultaneously, a commercial surrogate virus neutralization test (sVNT) was used for the determination of NAbs, expressed as inhibition percentage (% IH). RESULTS: Median values of anti-S1 IgG antibodies decreased from T1 (1,452 BAU/mL) to T6 (104 BAU/mL) with a percent variation of 92.8% while the sVNT showed a percent variation of 34.3% for the same time frame. The decline in anti-S1 IgG antibodies from T1 to T6 was not accompanied by a loss of the neutralizing capacity of antibodies. In fact at T6 a neutralization percentage <20% IH was observed only in 3.51% of HCWs. CONCLUSIONS: Our findings reveal that the decrease of anti-S1 IgG levels do not correspond in parallel to a decrease of NAbs over time, which highlights the necessity of using both assays to assess vaccination effectiveness.

2.
Frontiers in medicine ; 9, 2022.
Article in English | EuropePMC | ID: covidwho-1738050

ABSTRACT

Background A few studies on vaccination in patients with rheumatic diseases, including arthritis, connective tissue diseases, vasculitis, and psoriatic arthropathy (PsA), demonstrated reduced production of neutralizing antibodies to SARS-CoV-2 Spike RBD (receptor-binding domain contained in the N-terminal of the S1 globular head region) when compared to the general population. Objective The aim of our study was to observe whether different therapies for PsA [methotrexate, anti-TNF antibodies, soluble TNF receptor (etanercept) or IL-17 inhibitors] have a different impact on SARS-CoV-2 vaccination in a homogeneous population of patients. Methods We enrolled 110 PsA patients in remission, assessed with Disease Activity in PSoriatic Arthritis (DAPSA). Of these: 63 were in treatment with anti-TNF-α therapy (26 etanercept, 15 certolizumab, 5 golimumab, 17 adalimumab);37 with anti-IL17 secukinumab;10 with methotrexate. All patients underwent vaccination for SARS-CoV-2 with mRNA BNT162b2 vaccine. Assessment of absolute and percentage lymphocyte subsets and anti-SARS-CoV-2 Spike RBD IgG antibody value 3 weeks after the second vaccine dose were performed. In addition, the serum antibody levels of 96 healthy healthcare workers (HCW) were analyzed. Results The mean disease activity assessed with DAPSA score was 2.96 (SD = 0.60) with no significant differences between patients under different medications (p = 0.779). Median levels of neutralizing antibodies to SARS-CoV-2 Spike RBD were 928.00 binding antibody unit (BAU)/mL [IQR 329.25, 1632.0];1068.00 BAU/ml [IQR 475.00, 1632.00] in patients taking MTX, 846.00 BAU/ml [IQR 125.00, 1632.00] in patients taking etanercept, 908.00 BAU/mL [IQR 396.00, 1632.00] in patients taking anti-IL17 and 1148.00 BAU/ml [IQR 327.00, 1632.00] in patients taking TNF-α inhibitors, without statistically significant differences between these groups. Mean serum antibody level of HCW group was 1562.00 BAU/ml [IQR 975.00, 1632.00], being significantly higher than in the patient group (p = 0.000816). Absolute and percentage count of lymphocyte subsets were not statistically different between the subgroups under different treatments and when compared with HCW. Conclusions As for other rheumatic diseases on immunomodulatory treatment, our data showed a reduced humoral response in PsA patients compared to the control group. However, antibody response did not significantly differ between groups treated with different medications.

3.
Front Biosci (Landmark Ed) ; 27(2): 74, 2022 02 21.
Article in English | MEDLINE | ID: covidwho-1716430

ABSTRACT

BACKGROUND: Several commercial surrogate Virus Neutralization Tests (sVNTs) have been developed in the last year. Neutralizing anti-SARS-CoV-2 antibodies through interaction with Spike protein Receptor Binding Domain (S-RBD) can block the virus from entering and infecting host cells. However, there is a lack of information about the functional activity of SARS-CoV-2 antibodies that may be associated with protective responses. For these reasons, to counteract viral infection, the conventional virus neutralization test (VNT) is still considered the gold standard. The aim of this study was to contribute more and detailed information about sVNTs' performance, by determining in vitro the anti-SARS-CoV-2 neutralizing antibody concentration using four different commercial assays and then comparing the obtained data to VNT. METHODS: Eighty-eight samples were tested using two chemiluminescence assays (Snibe and Mindray) and two ELISA assays (Euroimmun and Diesse). The antibody titers were subsequently detected and quantified by VNT. RESULTS: The overall agreement between each sVNT and VNT was 95.45% for Euroimmun and 98.86% for Diesse, Mindray and Snibe. Additionally, we investigated whether the sVNTs were closer to the gold standard than traditional anti-SARS-CoV-2 antibody assays S-RBD or S1 based, finding a higher agreement mean value for sVNTs (98.01 ± 1.705% vs 95.45 ± 1.921%; p < 0.05). Furthermore, Spearman's statistical analysis for the correlation of sVNT versus VNT showed r = 0.666 for Mindray; r = 0.696 for Diesse; r = 0.779 for Mindray and r = 0.810 for Euroimmun. CONCLUSIONS: Our data revealed a good agreement between VNT and sVNTs. Despite the VNT still remains the gold standard, the sVNT might be a valuable tool for screening wider populations.


Subject(s)
Antibodies, Neutralizing , COVID-19 , Antibodies, Viral , COVID-19/diagnosis , Humans , Neutralization Tests , SARS-CoV-2
5.
Int Immunopharmacol ; 100: 108095, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1377734

ABSTRACT

BACKGROUND AND AIMS: SARS-CoV-2 antibody assays are relevant in managing the COVID-19 pandemic, providing valuable data on the immunization status of the population. However, current serology tests are highly variable, due to their different characteristics and to the lack of reference materials. The aim of the World Health Organization (WHO) first International Standard (IS) for anti-SARS-CoV-2 immunoglobulin is to harmonize humoral immune response assessment after natural infection or vaccination, and recommend reporting the results for binding activity in Binding Antibody Units (BAU). MATERIALS AND METHODS: This study analyzed six commercial quantitative anti-SARS-CoV-2 S-protein assays in a head-to-head comparison, using the manufacturers' conversion factors for the WHO IS to obtain BAU/mL values. RESULTS: Our data showed good alignment up to 1000 BAU/mL, then began to disperse, exhibiting some discrepancies. Moreover, correlations among methods varied with Cohen's Kappa ranging from 0.580 to 1.00, with the lowest agreement values for kits using different target antigens or different antibody isotypes, making it clear that the laboratory report should include this information. Values expressed as BAU/ml showed a reduced between-assays variability compared to AU/ml (median coefficients of variation 0.38 and 0.68, respectively; p < 0.001). CONCLUSION: On the basis of these data at present anti-SARS CoV-2 serological assays' results are not interchangeable, and, more importantly, individual immune monitoring should be performed with the same method.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/standards , COVID-19/diagnosis , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Female , Humans , Immunoglobulin G/blood , Male , Middle Aged , World Health Organization
8.
J Med Virol ; 93(3): 1436-1442, 2021 03.
Article in English | MEDLINE | ID: covidwho-1196450

ABSTRACT

During coronavirus disease 2019 (COVID-19) pandemic, the early diagnosis of patients is a priority. Serological assays, in particular immunoglobulin (Ig)M and IgG anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have today several applications but the interpretation of their results remains an open challenge. Given the emerging role of the IgA isotype in the COVID-19 diagnostics, we aimed to identify the SARS-CoV-2 IgA antibodies in a COVID-19 population seronegative for IgM. A total of 30 patients hospitalized in San Giovanni di Dio Hospital (Florence, Italy) for COVID-19, seronegative for IgM antibodies, have been studied for anti-SARS-CoV-2 antibodies. They all had a positive oro/nasopharyngeal swab reverse transcription-polymerase chain reaction result. Assays used were a chemiluminescent assay measuring SARS-CoV-2 specific IgM and IgG (S + N) and an ELISA, measuring specific IgG (S1) and IgA antibodies against SARS-CoV-2. Among the 30 patients, eight were positive for IgA, seven were positive for IgG (N + S), and two for IgG (S1), at the first point (5-7 days from the onset of symptoms). The IgA antibodies mean values at the second (9-13 days) and third (21-25 days) time points were even more than twice as high as IgG assays. The agreement between the two IgG assays was moderate (Cohen's K = 0.59; SE = 0.13). The inclusion of the IgA antibodies determination among serological tests of the COVID-19 diagnostic is recommended. IgA antibodies may help to close the serological gap of the COVID-19. Variations among anti-SARS-CoV-2 IgG assays should be considered in the interpretation of results.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19/diagnosis , Immunoglobulin A/blood , SARS-CoV-2/immunology , Adult , Aged , COVID-19/immunology , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoassay , Immunoglobulin G/blood , Immunoglobulin M/blood , Luminescent Measurements , Male , Middle Aged , Sensitivity and Specificity
10.
Riv. Ital. Med. Labor. ; 1(16): 7-17, 20200301.
Article in Italian | WHO COVID, ELSEVIER | ID: covidwho-659439

ABSTRACT

COVID-19 infection (SARS-CoV-2) is a viral disease first encountered in Wuhan, China, in December 2019, then rapidly spreading around the world. During this current public health emergency of international concern, screening and diagnosing patients quickly in order to aid containment is a priority. Most of our knowledge on diagnostics comes from previous studies on SARSCoV. Since SARS-CoV-2 belongs to the same large family of viruses as those that cause the MERS and SARS outbreak, we could assume that its antibody generation process should be similar. The high contagiousness and the characteristics of high lethality of the epidemic require efficient diagnostics, able to quickly identify the sources of the infection. The identification of patients with active SARS-CoV-2 infection is currently based on the amplification of a viral genome sequence using molecular biology techniques (real-time polymerase chain reaction), which can be subsequently confirmed by gene sequencing. However, the variability linked to the execution of the swab and the limitations of the test (complexity, biosecurity levels, costs and long response times) makes molecular diagnostics unsuitable for use in the field. Consequently, new tools such as serological tests capable of tracking the virus through each phase of the disease are in great demand. Serological antibody tests are already being developed and have already been introduced to the market. To date, however, there is no robust scientific evidence on the clinical-diagnostic reliability of these tests which therefore, at the moment, cannot replace the molecular test. The few studies in the literature are of limited thickness, sometimes discordant with each other and conducted on a small scale mainly on the Chinese population. In the absence of specific references, there is an open debate on the best use of these serological tests and on the ideal moment of their execution. In this review we describe the main characteristics of the SARS-CoV-2 virus, the diagnostic molecular strategies available today, and the first experimental data on the determination of antibodies directed towards SARS-CoV-2.

11.
J Med Virol ; 92(9): 1671-1675, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-116658

ABSTRACT

A pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading throughout the world. Though molecular diagnostic tests are the gold standard for COVID-19, serological testing is emerging as a potential surveillance tool, in addition to its complementary role in COVID-19 diagnostics. Indubitably quantitative serological testing provides greater advantages than qualitative tests but today there is still little known about serological diagnostics and what the most appropriate role quantitative tests might play. Sixty-one COVID-19 patients and 64 patients from a control group were tested by iFlash1800 CLIA analyzer for anti-SARS CoV-2 antibodies IgM and IgG. All COVID-19 patients were hospitalized in San Giovanni di Dio Hospital (Florence, Italy) and had a positive oro/nasopharyngeal swab reverse-transcription polymerase chain reaction result. The highest sensitivity with a very good specificity performance was reached at a cutoff value of 10.0 AU/mL for IgM and of 7.1 for IgG antibodies, hence near to the manufacturer's cutoff values of 10 AU/mL for both isotypes. The receiver operating characteristic curves showed area under the curve values of 0.918 and 0.980 for anti-SARS CoV-2 antibodies IgM and IgG, respectively. iFlash1800 CLIA analyzer has shown highly accurate results for the anti-SARS-CoV-2 antibodies profile and can be considered an excellent tool for COVID-19 diagnostics.


Subject(s)
Antibodies, Viral/immunology , COVID-19/diagnosis , COVID-19/immunology , Immunoassay , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Luminescent Measurements , SARS-CoV-2/immunology , Aged , Aged, 80 and over , Antibodies, Viral/blood , Automation, Laboratory , COVID-19/virology , Female , Humans , Immunoassay/methods , Immunoassay/standards , Immunoglobulin G/blood , Immunoglobulin M/blood , Luminescent Measurements/methods , Luminescent Measurements/standards , Male , Middle Aged , ROC Curve , Reproducibility of Results , Sensitivity and Specificity
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