Profile of specific antibodies to SARS-CoV-2: The first report

Abstract

•Profile of specific antibodies to virus in blood can assist diagnosis and reflect disease course.•The preliminary study explored the dynamic profile of IgM and IgG.•Serum IgM to SARS-COV-2 last more than a month indicating the prolonged virus replication in infected patients. A novel coronavirus (COVID-19) epidemic threatens the world.1Tang J.W. TAMbyah P.A. Hui D.S. Emergence of a novel coronavirus causing respiratory illness from Wuhan, China.J. Infect. 2020; (https://doi.org/)https://doi.org/10.1016/j.jinf.2020.01.014Abstract Full Text Full Text PDF Scopus (113) Google Scholar,2Zunyou W. Jennifer M.G. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in china: Summary of a report of 72,314 cases from the Chinese center for disease control and prevention.JAMA. 2020; (Published online February 24)https://doi.org/10.1001/jama.2020.2648Crossref Scopus (12455) Google Scholar Before this study, some studies reported cases of viral detection by RT-PCR at different timepoints throughout the disease course.3Zou L. Ruan F. Huang M. et al.SARS-CoV-2 viral load in upper respiratory specimens of infected patients.N Engl. J. Med. 2020; (Published online February 19)https://doi.org/10.1056/NEJMc2001737Crossref Scopus (3423) Google Scholar,4Pan Y. Zhang D.T. Yang P. et al.Viral load of SARS-CoV-2 in clinical samples.Lancet Infect Dis. 2020; (Published Online February 24)https://doi.org/10.1016/S1473-3099(20)30113-4Abstract Full Text Full Text PDF Scopus (1162) Google Scholar However, these reports monitored SARS-CoV-2 in the acute phase of infection. Currently no study reported the profile of specific antibodies to SARS-CoV-2 infection. Profile of specific antibodies in patients’ blood can assist diagnosis and reflect the disease course. Here, we first studied the profile of IgM and IgG for SARS-CoV-2 from 34 COVID-19 patients. A total of 34 hospitalized patients (admission date from Feb 1st to Feb 29th, 2020) with confirmed SARS-CoV-2 infection were included in this study. All enrolled patients were confirmed diagnosed of COVID-19 according to the diagnosis and treatment guideline for SARS-CoV-2 from Chinese National Health Committee (Version 5) and the interim guidance from Centers for Disease Control and Prevention.5Interim infection prevention and control recommendations for patients with confirmed coronavirus disease 2019 (COVID-19) or persons under investigation for COVID-19 in healthcare settings. (Update: February 21, 2020). https://www.cdc.gov/coronavirus/2019-ncov/hcp/infection-control.html.Google Scholar,6China National Health Commission Diagnosis and treatment of 2019-nCoV pneumonia in China; 2020. (Version 5) In Chinese. Published February 8Accessed March 3, 2020 http://www.nhc.gov.cn/yzygj/s7653p/202002/d4b895337e19445f8d728fcaf1e3e13a/files/ab6bec7f93e64e7f998d802991203cd6.pdfGoogle Scholar Blood samples were obtained at different date after onset of symptoms to detect the specific antibodies to SARS-CoV-2. IgM and IgG were analyzed by chemiluminescent immunoassay according to the manufacturer's protocol (Shenzhen Yahuilong Biotechnology Co., Ltd). All data (test dates and results of IgM and IgG) were collected up to the final follow-up date (March 3rd, 2020). Details of demographic characteristics and test dates and results of IgM and IgG were list in Table 1. Except for two patients (2 days and 3 days after symptoms onset), all included patients had IgM and IgG tests after 2 weeks from symptoms onset. We categorized patients by weeks according to the date of antibodies test after symptoms onset. In week 3 after symptoms onset, all patients were tested positive for IgM and IgG, with the mean value of 322.80AU/ml and 112.40AU/ml (Reference:<10AU/ml) respectively. In week 4, all the results were still positive for IgM and IgG. IgM declined while IgG continued to go up, with the mean value of 147.92AU/ml and 157.01AU/ml respectively. In week 5, however, all patients were positive for IgG, while 2 patients (16.7%) got negative results for IgM. IgM level kept going down to 78.03AU/ml and IgG continued up to 163.56AU/ml. At the end of observation (7 weeks), 2 patients (33.3%) got negative results for IgM, while all patients positive for IgG, with the mean value of 21.83AU/ml and 167.16AU/ml respectively. (Fig. 1)Table 1Characteristics of demographic and specific antibodies in COVID-19 patients (N = 34).PatientsAgeGenderIgM AU/mlIgG AU/mlTest days, after onsetWeekMean IgM AU/mlSEMMean IgG AU/mlSEMPatient182Female3.562.48212.241.331.960.53Patient287Female0.911.433Patient359Female122.73163.85143322.80127.65112.4021.43Patient472Male924187.414Patient532Female111.78110.1716Patient663Male207.3955.4317Patient769Male401.1978.7117Patient864Male169.7278.8221Patient965Female104.77187.94224147.9294.50157.0112.40Patient1039Male16.63152.8823Patient1152Male89.31179.1823Patient1249Male41.55128.7524Patient1335Male62.5103.8927Patient1431Male11.26193.8328Patient1558Female709.39152.572