Background::There have been many studies about coronavirus disease 2019 (COVID-19), but the clinical significance of quantitative serum severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-specific IgM and IgG levels of COVID-19 patients have not been exhaustively analyzed. We aimed to investigate the time profiles of these IgM/IgG levels in COVID-19 patients and their correlations with clinical features.Methods::A multicenter clinical study was conducted from February 20 to March 5 2020. It involved 179 COVID-19 patients (108 males and 71 females) from five hospitals in Huangshi in Hubei Province, China. To detect SARS-CoV-2-specific IgM/IgG, quantitative antibody assays (two-step indirect immunoassays with direct chemiluminescence technology) based on the nucleocapsid protein (NP) and spike protein 1 (S1) were used. For normally distributed data, means were compared using the t-test, χ2-test, or exact probability method. For categorical data, medians were compared using Mann-Whitney U test. Results::The median age was 57 (44-69) years (58 [38-69] for males and 57 [49-68] for females). The median duration of positive nucleic acid test was 22.32 (17.34-27.43) days. The mortality rate was relatively low (3/179, 1.68%). Serum SARS-CoV-2-specific IgG was detected around week 1 after illness onset, gradually increased until peaking in weeks 4 and 5, and then declined. Serum IgM peaked in weeks 2 and 3, then gradually declined and returned to its normal range by week 7 in all patients. Notably, children had milder respiratory symptoms with lower SARS-CoV-2-specific IgM/IgG levels. The duration of positive nucleic acid test in the chronic obstructive pulmonary disease (COPD) group was 30.36 (18.99-34.76) days, which was significantly longer than that in the non-COPD group (21.52 [16.75-26.51] days; P= 0.025). The peak serum SARS-CoV-2-specific IgG was significantly positively correlated with the duration of positive nucleic acid test. The incidence rate of severe and critical cases in the IgM hi group (using the median IgM level of 29.95 AU/mL as the cutoff for grouping) was about 38.0% (19/50), which was twice as much as that in the IgM lo group (18.4%; 9/49). The patients with positive chest imaging and lymphocytopenia (<1 × 10 9/L) had a higher SARS-CoV-2-specific IgM level. Conclusions::Quantitative SARS-CoV-2-specific IgM and IgG levels are helpful for the diagnosis, severity classification, and management of COVID-19 patients, and they should be monitored in each stage of this disease.

COVID-19;Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2);Serum IgM;Serum IgG;Clinical significance

Bai Zhenjiang;Li Qing;Chen Qinghui;Niu Changming;Wei Yu;Huang Hanpeng;Zhao Wei;Chen Nian;Yao Xin;Zhang Qiang;Mu Chuanyong;Feng Jian;Zhu Chuanlong;Li Zhuo;Ding Ming;Feng Binhui;Jin Chaochao;Lu Xiang;Yang Yi;Wu Shuiyan;Shu Xiaochen;Hu Lifang;Qiu Haibo;Huang YingZi

Pediatric Intensive Care Unit, Children’s Hospital of Soochow University, Suzhou, Jiangsu 215025, China;Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu 210009, China;Department of Infectious Diseases, Children’s Hospital of Soochow University, Suzhou, Jiangsu 215025, China;Department of Critical Care Medicine, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210011, China;Department of Respirology, Jiangsu Province Hospital of TCM, Nanjing, Jiangsu 210046, China;Department of Respirology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212001, China;Department of Critical Care Medicine, Sir Run Hospital Nanjing Medical University, Nanjing, Jiangsu 211112, China;Department of Infectious Diseases, The Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 211103, China;Department of Respiratory and Critical Care Medicine, The Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 211103, China;Department of Respirology, Southeast University Zhongda Hospital, Nanjing, Jiangsu 210009, China;Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China;Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226019, China;Department of Emergency, Children’s Hospital of Nanjing Medical University, Nanjing, Jiangsu 210008, China;Department of Critical Care Medicine, Huangshi Central Hospital, Huangshi, Hubei 435002, China;Department of Oncology, Huangshi Hospital of TCM (Infectious Disease Hospital, Huangshi, Hubei 435002, China;Department of Geriatric Medicine, Sir Run Hospital Nanjing Medical University, Nanjing, Jiangsu 211112, China;Department of Epidemiology, School of Public Health, Medical College of Soochow University, Suzhou, Jiangsu 215031, China;Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215031, China

重症医学（英文）

[1]Bai Zhenjiang;Li Qing;Chen Qinghui;Niu Changming;Wei Yu;Huang Hanpeng;Zhao Wei;Chen Nian;Yao Xin;Zhang Qiang;Mu Chuanyong;Feng Jian;Zhu Chuanlong;Li Zhuo;Ding Ming;Feng Binhui;Jin Chaochao;Lu Xiang;Yang Yi;Wu Shuiyan;Shu Xiaochen;Hu Lifang;Qiu Haibo;Huang YingZi-.Clinical significance of serum IgM and IgG levels in COVID-19 patients in Hubei Province, China ☆)[J].重症医学（英文）,2022(01):32-38

exhaustively,Huangshi,IgM ,lymphocytopenia

Clinical,significance,serum,IgG,levels,patients,Hubei,Province,China ,Background,There,have,been,many,studies,about,coronavirus,disease,clinical,quantitative,severe,acute,respiratory,syndrome,SARS,CoV,specific,not,analyzed,We,aimed,investigate,profiles,these,their,correlations,features,Methods,multicenter,study,was,conducted,from,February,March,It,involved,females,five,hospitals,To,antibody,two,step,indirect,immunoassays,chemiluminescence,technology,nucleocapsid,protein,NP,spike,S1,were,used,For,normally,distributed,data,means,compared,using,test,exact,probability,method,categorical,medians,Mann,Whitney,Results,years,duration,nucleic,acid,days,mortality,rate,relatively,Serum,detected,around,after,illness,onset,gradually,increased,until,peaking,weeks,then,declined,peaked,returned,its,range,by,Notably,children,had,milder,symptoms,lower,chronic,obstructive,pulmonary,COPD,which,significantly,longer,than,that,positively,correlated,incidence,critical,cases,AU,cutoff,grouping,twice,much,chest,imaging,10 ,higher,Conclusions,Quantitative,helpful,diagnosis,severity,classification,management,they,should,monitored,each,stage,this,Severe

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