Kinetics of SARS-CoV-2 Specific IgM and IgG Responses in COVID-19 Patients

Emerg Microbes Infect. 2020 Dec;9(1):940-948. doi: 10.1080/22221751.2020.1762515.

Abstract

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.

Keywords: C-reactive protein; COVID-19; IgG; IgM; SARS-CoV-2.

MeSH terms

  • Aged
  • Antibodies, Viral / blood
  • Antibodies, Viral / immunology*
  • Betacoronavirus / immunology*
  • C-Reactive Protein / analysis
  • C-Reactive Protein / immunology
  • Clinical Laboratory Techniques
  • Coronavirus Infections / blood
  • Coronavirus Infections / diagnosis
  • Coronavirus Infections / immunology*
  • Critical Care / statistics & numerical data
  • Female
  • Humans
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology*
  • Immunoglobulin M / blood
  • Immunoglobulin M / immunology*
  • Kinetics
  • Male
  • Middle Aged
  • Nucleocapsid Proteins / blood
  • Nucleocapsid Proteins / immunology*
  • Pandemics
  • Pneumonia, Viral / blood
  • Pneumonia, Viral / diagnosis
  • Pneumonia, Viral / immunology*
  • Spike Glycoprotein, Coronavirus / blood
  • Spike Glycoprotein, Coronavirus / immunology*

Substances

  • Antibodies, Viral
  • Immunoglobulin G
  • Immunoglobulin M
  • Nucleocapsid Proteins
  • Spike Glycoprotein, Coronavirus
  • nucleocapsid protein, Coronavirus
  • spike protein, SARS-CoV-2
  • C-Reactive Protein

Supplementary concepts

  • COVID-19
  • COVID-19 diagnostic testing
  • severe acute respiratory syndrome coronavirus 2

Grant support

This work was supported by the National Natural Science Foundation of China for SARS-CoV-2 (82041014), Guangzhou Health Care and Cooperative Innovation Major Project (201508020252), Zhejiang University special scientific research funding for COVID-19 prevention and control (2020XGZX001, 2020XGZX025).