ABSTRACT
Confirming detected SARS-CoV-2-specific antibodies is necessary to reveal immune response in COVID-19 convalescent subjects as well as to conduct population studies by screening for specific antibodies to assess rate of COVID-19 prevalence. With this purpose St. Petersburg Pasteur Institute was the first in Russia to develop the ELISA kit for the quantitative determination of human IgG to the SARS-CoV-2 nucleocapsid (N-CoV-2-IgG PS). Arbitrary units (AU/ml) were used to assess the level of antibodies. The data shown in AU/ml were recalculated later to the international units (BAU/ml) in accordance with established the First WHO International Standard for anti-SARS-CoV-2 human Immunoglobulin. Comparing the data of the N-CoV-2-IgG PS calibration curve with those of the First WHO International Standard for anti-SARS- CoV-2 human Immunoglobulin revealed a complete inter-assay association (r = 0.999, R-2 = 0.997) allowing to find that 1BAU/ml = 5.97 AU/ml. The aim of the study was to characterize the "SARS-CoV-2 protein N Human IgG Quantitative ELISA Kit" (N-CoV-2-IgG PS), compare quantitative and qualitative data of ELISA kits, assess a correlation between the binding antibodies to SARS-CoV-2 N proteins and the neutralizing antibodies against SARS-CoV-2. The data of correlation analysis of the 83 COVID-19 convalescent blood plasma samples a significant relationship between the antibodies quantitative values and titers SARS-CoV-2-specific antibody (r = 0.8436, R-2 = 0.7802) as well as a moderate relationship between antibody concentration and positivity index (r = 0.6648, R-2 = 0.3307), assessed by Chaddock scale. Comparing concentration of N-protein binding antibodies with neutralizing antibody titers level uncovered data consistency obtained by quantitative and virus microneutralization assays (r = 0.7310, R-2 = 0.6527) used in parallel to analyze 80 blood plasma samples obtained from COVID-19 patients and convalescents. AUC under the ROC curve comprised 0.701 (P < 0.0001) evidencing about a satisfactory informative value for "N-CoV-2-IgG PS" compared with microneutralization assay. In addition, the efficacy of the "N-CoV-2-IgG PS" was 95%, while the positive and negative prognostic value was 97% and 87%, respectively. The data obtained confirmed a correlation between N-protein binding antibody level and neutralizing antibody titer. Checking inter-assay agreement evidenced about acceptance for informativeness and efficacy of using "N-CoV-2-IgG PS", thereby confirming an opportunity to apply the Kit to screen for SARS-CoV-2 N protein-specific IgG antibody level and assess seroprevalence in diverse population cohorts.
ABSTRACT
In our study, we aimed to evaluate the significance of specific cytokines in blood plasma as predictive markers of COVID-associated mortality. Materials and methods. In plasma samples of 29 patients with PCR-confirmed COVID-19 we measured the concentrations of 47 molecules. These molecules included: interleukins and selected pro-inflammatory cytokines (IL-1alpha, IL-1beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A/CTLA8, IL-17-E/IL-25, IL-17F, IL-18, IL-22, IL-27, IFNalpha2, IFNgamma, TNFalpha, TNFbeta/Lymphotoxin-alpha(LTA));chemokines (CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta, CCL7/MCP-3, CCL11/Eotaxin, CCL22/MDC, CXCL1/GROalpha, CXCL8/IL-8, CXCL9/MIG, CXCL10/IP-10, CX3CL1/Fractalkine);anti-inflammatory cytokines (IL-1Ra, IL-10);growth factors (EGF, FGF-2/FGF-basic, Flt-3 Ligand, G-CSF, M-CSF, GM-CSF, PDGF-AA, PDGFAB/BB, TGFalpha, VEGF-A);and sCD40L. We used multiplex analysis based on xMAP technology (Luminex, USA) using Luminex MagPix. As controls, we used plasma samples of 20 healthy individuals. Based on the results, we applied Receiver Operating Characteristic (ROC) analysis and Area Under Curve (AUC) values to compare two different predictive tests and to choose the optimal division point for disease outcome (survivors/non-survivors). To find optimal biomarker combinations, we as used cytokines concentrations as dependent variables to grow a regression tree using JMP 16 Software.Results. Out of 47 studied cytokines/chemokines/growth factors, we picked four pro-inflammatory cytokines as having high significance in evaluation of COVID-19 outcome: IL-6, IL-8, IL-15, and IL-18. Based on the results received, we assume that the highest significance in terms of predicting the outcome of acute COVID-19 belongs to IL-6 and IL-18. Conclusion. Analyzing concentrations of IL-6 and IL-18 before administering treatment may prove valuable in terms of outcome prognosis. Copyright © Arsentieva N.A. et al., 2022.
ABSTRACT
In our study, we aimed to evaluate the significance of specific cytokines in blood plasma as predictive markers of COVID-associated mortality. Materials and methods. In plasma samples of 29 patients with PCR-confirmed COVID-19 we measured the concentrations of 47 molecules. These molecules included: interleukins and selected pro-inflammatory cytokines (IL-1alpha, IL-1beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A/CTLA8, IL-17-E/IL-25, IL-17F, IL-18, IL-22, IL-27, IFNalpha2, IFNgamma, TNFalpha, TNFbeta/Lymphotoxin-alpha(LTA));chemokines (CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta, CCL7/MCP-3, CCL11/Eotaxin, CCL22/MDC, CXCL1/GROalpha, CXCL8/IL-8, CXCL9/MIG, CXCL10/IP-10, CX3CL1/Fractalkine);anti-inflammatory cytokines (IL-1Ra, IL-10);growth factors (EGF, FGF-2/FGF-basic, Flt-3 Ligand, G-CSF, M-CSF, GM-CSF, PDGF-AA, PDGFAB/BB, TGFalpha, VEGF-A);and sCD40L. We used multiplex analysis based on xMAP technology (Luminex, USA) using Luminex MagPix. As controls, we used plasma samples of 20 healthy individuals. Based on the results, we applied Receiver Operating Characteristic (ROC) analysis and Area Under Curve (AUC) values to compare two different predictive tests and to choose the optimal division point for disease outcome (survivors/non-survivors). To find optimal biomarker combinations, we as used cytokines concentrations as dependent variables to grow a regression tree using JMP 16 Software.Results. Out of 47 studied cytokines/chemokines/growth factors, we picked four pro-inflammatory cytokines as having high significance in evaluation of COVID-19 outcome: IL-6, IL-8, IL-15, and IL-18. Based on the results received, we assume that the highest significance in terms of predicting the outcome of acute COVID-19 belongs to IL-6 and IL-18. Conclusion. Analyzing concentrations of IL-6 and IL-18 before administering treatment may prove valuable in terms of outcome prognosis. Copyright © Arsentieva N.A. et al., 2022.
ABSTRACT
The Bioethics Committee of Belarus and the local ethics committee of the St. Petersburg Pasteur Institute approved the study. Selection of participants was carried out using a questionnaire method and online technology (internet, cloud server). Volunteers were randomized into seven age groups (years of age): 1–17;18–29;30–39;40–49;50–59;60–69;and 70+. Regional randomization ensured proportional representation of volunteers from each region, and no more than 30 people were included from one enterprise. In accordance with manufacturer instructions, blood plasma samples were analyzed for: IgG antibodies (Abs) to the SARS-CoV-2 nucleocapsid (Nc) using a quantitative ELISA test system;and IgG Abs to the receptor binding domain (RBD) of the SARS-CoV-2 S (spike) surface glycoprotein using a qualitative ELISA test system. Statistical processing was carried out using Excel 2010 and other software. Statistical differences were designated as significant when p < 0.05, unless otherwise indicated. Results. The level of seroprevalence, in terms of Abs to Nc among the Belarusian population, was 38.4% (95% CI 37.6–45.4). The highest Ab levels were found among individuals in older age groups (50-70+ years old). The lowest were found in children 1–17 years old and in young people 18–39 years old The distribution of seroprevalence across Belarusian regions was relatively homogeneous, with the exception of the Minsk Region, where a statistically significant decrease in the indicator was noted. In terms of profession, the largest share of seropositive individuals was found among transportation workers;the smallest was found in business. The moderate COVID-19 incidence has not led to a dramatic increase in the number of contacts. The base reproduction number (R0) was 1.3. In the Republic of Belarus, there was a moderate level of asymptomatic COVID-19 among seropositive individuals (45.3% [95% CI 44.0–46.7]). This form of infection was observed most often among children aged 1–17 years old (65.0% [95% CI 61.3–68.6]). In parallel with seroprevalence assessment, SARS-CoV-2 vaccination was carried out. We used two vaccines: Gam-COVID-Vac (also known as Sputnik V, developed by Gamaleya National Center for Epidemiology and Microbiology, Russia);and BBIBP-CorV (Sinopharm, PRC). Vaccination against SARS-CoV-2 was accompanied by an increase in the level of anti-RBD Abs (95% [95% CI 94.7–96.7]). Taking into account the vaccination of a subset of the population with BBIBP-CorV, the overall herd immunity, inferred from the analyzed indicators (presence of anti-Nc or anti-RBD Abs), was 47.1% (95% CI 46.3–48.0). Conclusion. COVID-19 in Belarus was characterized by a moderately pronounced course of the epidemic process. The threshold level of herd immunity to SARS-CoV-2 has not yet been reached, as a result of which the conditions for progression of the epidemic remain.
ABSTRACT
COVID-19, an infection caused by the new coronavirus SARS-CoV-2, is associated with a number of pathophysiological mechanisms, mobilizing a wide spectrum of biomolecules, mainly, cytokines. The purpose of this study was to evaluate levels of multiple cytokines in blood plasma from the patients with COVID-19 during acute phase of the disease, and upon complete recovery. Samples of peripheral blood plasma of 56 patients with COVID-19, 69 convalescents and 10 healthy individuals were examined. Concentrations of 46 molecules, such as IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A/CTLA8, IL-17-E/IL-25, IL-17F, IL-18, IL-22, IL-27, IFNα2, IFNγ, TNFα, TNFβ/ Lymphotoxin-α (LTA), CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CCL7/MCP-3, CCL11/Eotaxin, CCL22/MDC, CXCL1/GROα, CXCL8/IL-8, CXCL9/MIG, CXCL10/IP-10, CX3CL1/Fractalkine, IL-1ra, IL-10, EGF, FGF-2/FGF-basic, Flt3 Ligand, G-CSF, M-CSF, GM-CSF, PDGF-AA, PDGF-AB/ BB, TGF-α, VEGF-A were measured via xMAP multiplexing technology. Significantly increased levels of 18 cytokines were found in blood plasma from COVID-19 patients during acute phase of the disease (as compared to control group), i.e., IL-6, IL-7, IL-15, IL-27, TNFα, TNFβ/Lymphotoxin-α (LTA), CCL2/MCP-1, CCL7/MCP-3, CXCL1/GROα, CXCL8/IL-8, CXCL10/IP-10, CXCL9/MIG, IL-1rа, IL-10, M-CSF, GM-CSF, VEGF-A. We found a significant decrease of nearly all the mentioned cytokines in recovered patients, in comparison with those who had moderate, severe/extremely severe disease. Moreover, we revealed a significantly decreased level of 8 cytokines in plasma from convalescents, as compared with control group, i.e., IL-1α, IL-2, IL-9, IL-12 p40, IL-18, CCL22/MDC, Flt3 Ligand, TGF-α. Immune response caused by SARS-CoV-2 infection involves multiple cytokines, mostly, with pro-inflammatory effects. We have shown for the first time that the convalescence phase is characterized by significantly lower levels of cytokines which regulate cellular differentiation and hematopoiesis (in particular, lymphocytes, T-cells and NK-cells). Over acute phase of the disease, the levels of these cytokines did not change. We revealed a significant decrease of most plasma cytokines upon recovery as compared to acute phase. On the contrary, acute phase of the disease is accompanied by significant increase of both pro- and antiinflammatory cytokines in blood plasma.