TY - JOUR
T1 - Assessment of humoral responses in COVID-19 using various quantitative antibody tests
AU - Wakui, Masatoshi
AU - Uwamino, Yoshifumi
AU - Kurafuji, Toshinobu
AU - Noguchi, Masayo
AU - Ohno, Akemi
AU - Yokota, Hiromitsu
AU - Kikuchi, Haruhito
AU - Hasegawa, Naoki
AU - Saya, Hideyuki
AU - Murata, Mitsuru
N1 - Funding Information:
We thank the medical staffs of Keio University Hospital for their great contribution to clinical work on COVID-19. The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This study was funded by research fund for COVID-19 of Keio University School of Medicine.
Funding Information:
The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This study was funded by research fund for COVID-19 of Keio University School of Medicine.
Publisher Copyright:
© The Author(s) 2021.
PY - 2021/7
Y1 - 2021/7
N2 - Background: Quantitative antibody tests are expected to be useful in diagnostics of COVID-19 and investigation of herd immunity against SARS-CoV-2. To make it proper to perform them, understanding of the immunological aspects is critically important. The present study aimed to assess humoral responses in COVID-19 using various quantitative antibody tests. Methods: Four quantitative antibody tests that are different in targeted antigens, detectable immunoglobulin classes and avidity were used. Diagnosis was confirmed by RT-PCR for SARS-CoV-2 detection. Antibody titres of 117 samples collected from 24 COVID-19 patients and 23 non-COVID-19 patients were measured to evaluate correlations between different tests. For 24 COVID-19 patients, antibody titres measured at various time points after the onset or the RT-PCR diagnosis were subjected to assessment of humoral responses. Results: Correlations between tests were observed to some degree, although there were discrepancies putatively due to differences in measurement principle. Seronegative COVID-19 was diagnosed for some patients, in whom antibody titres were less than the cut-off value in each test throughout the time courses. IgG seroconversion without prior IgM seroconversion most frequently occurred, while predominance of IgM responses over IgG responses was observed in some severe cases. Viral burdens estimated according to threshold cycle values at the RT-PCR seemed to impact antibody responses. Conclusions: The results provide insights into the nature of humoral responses to SARS-CoV-2 and diagnostic performance of antibody tests.
AB - Background: Quantitative antibody tests are expected to be useful in diagnostics of COVID-19 and investigation of herd immunity against SARS-CoV-2. To make it proper to perform them, understanding of the immunological aspects is critically important. The present study aimed to assess humoral responses in COVID-19 using various quantitative antibody tests. Methods: Four quantitative antibody tests that are different in targeted antigens, detectable immunoglobulin classes and avidity were used. Diagnosis was confirmed by RT-PCR for SARS-CoV-2 detection. Antibody titres of 117 samples collected from 24 COVID-19 patients and 23 non-COVID-19 patients were measured to evaluate correlations between different tests. For 24 COVID-19 patients, antibody titres measured at various time points after the onset or the RT-PCR diagnosis were subjected to assessment of humoral responses. Results: Correlations between tests were observed to some degree, although there were discrepancies putatively due to differences in measurement principle. Seronegative COVID-19 was diagnosed for some patients, in whom antibody titres were less than the cut-off value in each test throughout the time courses. IgG seroconversion without prior IgM seroconversion most frequently occurred, while predominance of IgM responses over IgG responses was observed in some severe cases. Viral burdens estimated according to threshold cycle values at the RT-PCR seemed to impact antibody responses. Conclusions: The results provide insights into the nature of humoral responses to SARS-CoV-2 and diagnostic performance of antibody tests.
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U2 - 10.1177/00045632211006740
DO - 10.1177/00045632211006740
M3 - Article
C2 - 33730868
AN - SCOPUS:85104261949
VL - 58
SP - 368
EP - 376
JO - Annals of Clinical Biochemistry
JF - Annals of Clinical Biochemistry
SN - 0004-5632
IS - 4
ER -