Abstract
ObjectivesOur objective was to determine the antibody and cytokine profiles in different COVID-19 patients.MethodsCOVID-19 patients with different clinical classifications were enrolled in this study. The level of IgG antibodies, IgA, IgM, IgE, and IgG subclasses targeting N and S proteins were tested using ELISA. Neutralizing antibody titers were determined by using a toxin neutralization assay (TNA) with live SARS-CoV-2. The concentrations of 8 cytokines, including IL-2, IL-4, IL-6, IL-10, CCL2, CXCL10, IFN-γ, and TNF-α, were measured using the Protein Sample Ella-Simple ELISA system. The differences in antibodies and cytokines between severe and moderate patients were compared by t-tests or Mann-Whitney tests.ResultsA total of 79 COVID-19 patients, including 49 moderate patients and 30 severe patients, were enrolled. Compared with those in moderate patients, neutralizing antibody and IgG-S antibody titers in severe patients were significantly higher. The concentration of IgG-N antibody was significantly higher than that of IgG-S antibody in COVID-19 patients. There was a significant difference in the distribution of IgG subclass antibodies between moderate patients and severe patients. The positive ratio of anti-S protein IgG3 is significantly more than anti-N protein IgG3, while the anti-S protein IgG4 positive rate is significantly less than the anti-N protein IgG4 positive rate. IL-2 was lower in COVID-19 patients than in healthy individuals, while IL-4, IL-6, CCL2, IFN-γ, and TNF-α were higher in COVID-19 patients than in healthy individuals. IL-6 was significantly higher in severe patients than in moderate patients. The antibody level of anti-S protein was positively correlated with the titer of neutralizing antibody, but there was no relationship between cytokines and neutralizing antibody.ConclusionsOur findings show the severe COVID-19 patients’ antibody levels were stronger than those of moderate patients, and a cytokine storm is associated with COVID-19 severity. There was a difference in immunoglobulin type between anti-S protein antibodies and anti-N protein antibodies in COVID-19 patients. And clarified the value of the profile in critical prevention.
Highlights
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide for more than a year
The materials for indirect chemical luminescence analysis (CLIA) to measure IgG antibodies against SARS-CoV-2 spike protein and nucleoprotein were provided by Beijing KEWEI Clinical Diagnostic Reagent Inc
The plate was placed on an ELISA reader to acquire a relative light unit (RLU)
Summary
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide for more than a year. As of March 2021, SARS-CoV-2 has infected more than 100 million people worldwide, resulting in more than 2 million deaths, and the global epidemic situation of SARS-CoV-2 remains serious. Individuals infected by SARS-CoV-2 have different clinical symptoms. Most individuals have moderate symptoms, such as fever, respiratory tract symptoms, and imaging features of pneumonia. 14% of people have severe symptoms [1], such as respiratory distress and respiratory rate ≥30 times/min, mean oxygen saturation ≤93% at resting-state, or arterial blood oxygen partial pressure (PaO2)/oxygen concentration (FiO2) ≤300 mmHg (1 mmHg = 0.133 kPa) and progressive aggravation of clinical symptoms. Considering that the case-fatality rate of critical COVID-19 patients is as high as 2.3% [1,2,3], it is important to clarify the internal mechanism of severe illness
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
