IgM and IgG Immunoreactivity of SARS-CoV-2 Recombinant M Protein.
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ABSTRACT:
SUBMITTER: Lopandic Z
PROVIDER: S-EPMC8125631 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The COVID-19 pandemic, caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread worldwide. Serological testing for SARS-CoV-2-specific antibodies plays an important role in understanding and controlling the pandemic, notably through epidemiological surveillance. Well-validated and highly specific SARS-CoV-2 serological assays are urgently needed. We describe here the analytical and clinical performance of Vidas SARS-CoV-2 IgM and Vidas SARS-CoV-2 IgG, two CE-marked, emergency use authorization (EUA)-authorized, automated, qualitative assays for the detection of SARS-CoV-2-specific IgM and IgG, respectively. Both assays showed high within-run and within-laboratory precision (coefficients of variation < 11.0%) and very low cross-reactivity toward sera of patients with a past common coronavirus or respiratory virus infection. Clinical specificity determined on up to 989 prepandemic healthy donors was ≥99% with a narrow 95% confidence interval for both IgM and IgG assays. Clinical sensitivity was determined on up to 232 samples from 130 reverse transcriptase PCR (RT-PCR)-confirmed SARS-CoV-2 patients. The positive percent agreement (PPA) with SARS-CoV-2 PCR reached 100% at ≥16 days (Vidas SARS-CoV-2 IgM) and ≥32 days (Vidas SARS-CoV-2 IgG) of symptom onset. Combined IgM/IgG test results improved the PPA compared to each test alone. SARS-CoV-2 IgG seroconversion followed closely that of SARS-CoV-2 IgM and remained stable over time, while SARS-CoV-2 IgM levels rapidly declined. Interestingly, SARS-CoV-2-specific IgM and IgG responses were significantly higher in COVID-19 hospitalized versus nonhospitalized patients. Altogether, the Vidas SARS-CoV-2 IgM and IgG assays are highly specific and sensitive serological tests suitable for the reliable detection of past acute SARS-CoV-2 infections.
| S-EPMC8092742 | biostudies-literature
Project description:Differentiating COVID-19 from other causes of viral pneumonia, like herpes simplex (HSV), can be complicated by shared clinical and laboratory features. Viral pneumonia is mostly diagnosed based on molecular or serological techniques. Serological immunoassay interferences, often attributed to concurrent appearance of heterologous (viral) immunoglobulins, is well-known, but has not been studied in COVID-19 patients. Following false positive HSV immunoglobulin M (IgM) results in our index patient, 25 other COVID-19 patients were tested for HSV-1/2 IgM with the chemiluminescent Liaison assay and Euroimmun enzyme-linked immunosorbent assay. Forty-five percent of COVID-19 patients tested positive for HSV IgM with Liaison. No HSV indices were positive with Euroimmun enzyme-linked immunosorbent assay, suggesting immunoassay interference. Significant correlation between HSV IgM and SARS-CoV-2 IgM/IgG positivity was found. Adding 0.5% polyvinylpyrrolidone, inhibiting non-specific solid-phase adsorption, abolished interference in 22% of false positive cases, suggesting interference caused by solid-phase reactive IgM. Hence, serologic immunoassay results should be interpreted with caution in COVID-19 patients.
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Project description:The emerging COVID-19 caused by SARS-CoV-2 infection poses severe challenges to global public health. Serum antibody testing is becoming one of the critical methods for the diagnosis of COVID-19 patients. We investigated IgM and IgG responses against SARS-CoV-2 nucleocapsid (N) and spike (S) protein after symptom onset in the intensive care unit (ICU) and non-ICU patients. 130 blood samples from 38 COVID-19 patients were collected. The levels of IgM and IgG specific to N and S protein were detected by ELISA. A series of blood samples were collected along the disease course from the same patient, including 11 ICU patients and 27 non-ICU patients for longitudinal analysis. N and S specific IgM and IgG (N-IgM, N-IgG, S-IgM, S-IgG) in non-ICU patients increased after symptom onset. N-IgM and S-IgM in some non-ICU patients reached a peak in the second week, while N-IgG and S-IgG continued to increase in the third week. The combined detection of N and S specific IgM and IgG could identify up to 75% of SARS-CoV-2 infected patients in the first week. S-IgG was significantly higher in non-ICU patients than in ICU patients in the third week. In contrast, N-IgG was significantly higher in ICU patients than in non-ICU patients. The increase of S-IgG positively correlated with the decrease of C-reactive protein (CRP) in non-ICU patients. N and S specific IgM and IgG increased gradually after symptom onset and can be used for detection of SARS-CoV-2 infection. Analysis of the dynamics of S-IgG may help to predict prognosis.
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Project description:We still know very little about how the human immune system responds to SARS-CoV-2. Here we construct a SARS-CoV-2 proteome microarray containing 18 out of the 28 predicted proteins and apply it to the characterization of the IgG and IgM antibodies responses in the sera from 29 convalescent patients. We find that all these patients had IgG and IgM antibodies that specifically bind SARS-CoV-2 proteins, particularly the N protein and S1 protein. Besides these proteins, significant antibody responses to ORF9b and NSP5 are also identified. We show that the S1 specific IgG signal positively correlates with age and the level of lactate dehydrogenase (LDH) and negatively correlates with lymphocyte percentage. Overall, this study presents a systemic view of the SARS-CoV-2 specific IgG and IgM responses and provides insights to aid the development of effective diagnostic, therapeutic and vaccination strategies.
| S-EPMC7360742 | biostudies-literature
Project description:The serological testing of anti-SARS-CoV-2 immunoglobulin G (IgG) and/or IgM is widely used in the diagnosis of COVID-19. However, its diagnostic efficacy remains unclear. In this study, we searched for diagnostic studies from the Web of Science, PubMed, Embase, CNKI, and Wanfang databases to calculate the pooled diagnostic accuracy measures using bivariate random-effects model meta-analysis. As a result, 22 from a total of 1613 articles, including 2282 patients with SARS-CoV-2 and 1485 healthy persons or patients without SARS-CoV-2, were selected for a meta-analysis. Pooled sensitivity, specificity, and area under curve of the summary receiver operator curve (SROC) were: (a) 0.85 (95% confidence interval [CI]: 0.79-0.90), 0.99 (95% CI: 0.98-1.00), and 0.99 (95% CI: 0.97-0.99) for anti-SARS-CoV-2 IgG and (b) 0.74 (95% CI: 0.65-0.81), 0.99 (95% CI: 0.97-1.00), and 0.95 (95% CI: 0.93-0.97) for IgM. A subgroup analysis among detection methods indicated the sensitivity of IgG and IgM using enzyme-linked immunosorbent assay were slightly lower than those using gold immunochromatography assay (GICA) and chemiluminescence immunoassay (P > .05). These results showed that the detection of anti-SARS-CoV-2 IgG and IgM had high diagnostic efficiency to assist the diagnosis of SARS-CoV-2 infection. And, GICA might be used as the preferred method for its accuracy and simplicity.
| S-EPMC7361902 | biostudies-literature
Project description:ObjectiveTo explore the clinical value of serum IgM and IgG to SARS-CoV-2 in COVID-19.Methods105 COVID-19 patients were enrolled as the disease group. 197 non-COVID-19 patients served as the control group. Magnetic chemiluminescent immunoassay (MCLIA) was used to detect the IgM and IgG.ResultsThe peak of positive rates of SARS-CoV-2 IgM was about 1 week earlier than that of IgG. It reached to peak within 15-21 days and then began a slowly decline. The positive rates of IgG were increased with the disease course and reached the peak between 22 and 39 days. The differences in sensitivity of the three detection modes (IgM, IgG, and IgM + IgG) were statistically significant. The largest group of test cases (illness onset 15-21 days) showed that the positive rate of IgG was higher than IgM. Also, the sensitivity of IgM combined with IgG was higher than IgM or IgG. IgM and IgG were monitored dynamically for 16 patients with COVID-19, the results showed that serological transformation of IgM was carried out simultaneously with IgG in seven patients, which was earlier than IgG in four patients and later than IgG in five patients.ConclusionThe detection of SARS-CoV-2 IgM and IgG is very important to determine the course of COVID-19. Nucleic acid detection combined with serum antibody of SARS-CoV-2 may be the best laboratory indicator for the diagnosis of SARS-CoV-2 infection and the phrase and predication for prognosis of COVID-19.
| S-EPMC7843265 | biostudies-literature
Project description:To tackle the COVID-19 outbreak, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is an unmet need for highly accurate diagnostic tests at all stages of infection with rapid results and high specificity. Here, we present a label-free nanoplasmonic biosensor-based, multiplex screening test for COVID-19 that can quantitatively detect 10 different biomarkers (6 viral nucleic acid genes, 2 spike protein subunits, and 2 antibodies) with a limit of detection in the aM range, all within one biosensor platform. Our newly developed nanoplasmonic biosensors demonstrate high specificity, which is of the upmost importance to avoid false responses. As a proof of concept, we show that our detection approach has the potential to quantify both IgG and IgM antibodies directly from COVID-19-positive patient plasma samples in a single instrument run, demonstrating the high-throughput capability of our detection approach. Most importantly, our assay provides receiving operating characteristics, areas under the curve of 0.997 and 0.999 for IgG and IgM, respectively. The calculated p-value determined through the Mann-Whitney nonparametric test is <0.0001 for both antibodies when the test of COVID-19-positive patients (n = 80) is compared with that of healthy individuals (n = 72). Additionally, the screening test provides a calculated sensitivity (true positive rate) of 100% (80/80), a specificity (true negative rate) >96% (77/80), a positive predictive value of 98% at 5% prevalence, and a negative predictive value of 100% at 5% prevalence. We believe that our very sensitive, multiplex, high-throughput testing approach has potential applications in COVID-19 diagnostics, particularly in determining virus progression and infection severity for clinicians for an appropriate treatment, and will also prove to be a very effective diagnostic test when applied to diseases beyond the COVID-19 pandemic.
| S-EPMC8230954 | biostudies-literature
Project description:The clinical and public health utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing requires a better understanding of the dynamics of the humoral response to infection. To track seroconversion of IgG and IgM antibodies in patients with SARS-CoV-2 infection and its association with patient and clinical factors and outcomes. Residual patient specimens were analyzed on the Abbott ARCHITECT i2000 instrument using the Abbott SARS-CoV-2 IgG assay and prototype SARS-CoV-2 IgM assay. Age, sex, comorbidities, symptom onset date, mortality, and specimen collection date were obtained from electronic medical records. Three hundred fifty-nine longitudinal samples were collected from 89 hospitalized patients 0 to 82 days postsymptom onset. Of all, 51.7% of the patients developed IgG and IgM antibodies simultaneously; 32.8% seroconverted for IgM before IgG. On average, patients seroconverted for IgG by 8 days and for IgM by 7 days postsymptom onset. All patients achieved IgG seropositivity by 19 days and IgM seropositivity by 17 days. Median time to IgG and IgM seroconversion was prolonged and initial levels of IgG were lower in immunocompromised patients and patients <65 years of age compared to immune competent patients and those ?65 years of age. Immunocompromised patients also had persistently lower levels of IgM that peaked on day 17.6 and decreased thereafter compared to immune competent patients. IgM seroconversion in patients who died reached significantly higher levels later after symptom onset than in those who recovered. SARS-CoV-2 infected patients have similar time to seroconversion for IgG and IgM. However, differences in immune status and age alter time to seroconversion. These results may help guide serologic testing application in COVID-19 management.
| S-EPMC7759125 | biostudies-literature
Project description:BackgroundClinical laboratory testing has been an essential part of COVID-19 management. Serology can provide valuable information regarding a patient's exposure to virus, and may have a larger role to play as vaccines becomes available. Limited data is available on the serological response in pediatric patients. Here we investigate the use of one manufacturer's commercial assays for detecting IgM and IgG in an exclusively pediatric population.MethodsAbbott SARS-CoV-2 IgM and IgG assays were performed on an Abbott ARCHITECT i1000. For specificity studies, we tested 78 patient specimens collected before the COVID-19 pandemic, and 66 specimens from patients who tested negative for SARS-CoV-2 nucleic acid amplification test (NAAT) during the COVID-19 pandemic. For sensitivity we tested 181 specimens from 41 patients with a positive NAAT result. Precision data was acquired for 20 days.ResultsFor IgM, the highest qualitative positive agreement with molecular results was observed to be 15-30 days after a positive NAAT result or after symptom onset. For IgG, the highest positive agreement was 31-60 days after a positive NAAT result or 61-90 days after the start of symptoms. IgM started to decline 30 days after NAAT results and faded by 90 days. IgG started to decrease 60 days after a positive NAAT result.ConclusionThe Abbott IgM and IgG assays have negative agreements of 98.7-100% relative to NAAT results. The IgM and IgG levels assayed by these methods start to decline months after positive molecular results and onset of symptoms in a pediatric population.
| S-EPMC7893289 | biostudies-literature
Project description:BackgroundSeldom performance evaluation and diagnosis comparison studies were reported for different chemiluminescent immunoassay (CLIA) kits approved under an emergency approval program for SARS-CoV-2 infection.MethodsA total of 100 and 105 serum separately from non-infected populations and COVID-19 patients were detected with SARS-CoV-2 IgM and IgG kits. The characteristics including precision, functional sensitivity, linearity, and accuracy were evaluated for Axceed, iFlash, and Maglumi CLIA kits.ResultsMaglumi and iFlash had the best analytical sensitivity for IgM and IgG, respectively. Axceed kits had a linearity response in the detected concentration. The clinical sensitivity of Axceed, iFlash, and Maglumi was 68.0%, 64.9%, and 63.9% with a specificity of 99.0%, 96.0%, and 100% for IgM, 85.6%, 97.9%, and 94.8% with a specificity of 97.0% for IgG. ROC analysis indicated all kits had a diagnostic power greater than 0.9. Notably, either IgM or IgG kits obtained a poor agreement (Kappa value from 0.397 to 0.713) with others. Among 38 recovered patients, 94.7% had an effective immune response, and both seropositive IgM and IgG accounted for the biggest proportion (medium, 42 days onset), then followed by the single seropositive IgG (medium, 50 days onset) in Ab profile.ConclusionThe performance of CLIA kits satisfied the diagnosis of SARS-CoV-2 infection. Both positive of IgG and IgM contributes to improve the specificity, and a positive one will enhance the sensitivity.
| S-EPMC7843253 | biostudies-literature