Acute phase of COVID-19 is associated with elevated plasmablasts in the blood

• Published in: Bratislavské lékarské listy Vol. 123; no. 4; pp. 244 - 247
• Main Authors: Beran, Ondrej, Matuskova, Katerina, Bartovska, Zofia, Bartos, Oldrich, Holub, Michal
• Format: Journal Article
• Language: English
• Published: Slovakia 2022
• Subjects: Antibodies, Viral; COVID-19; Humans; Immunoglobulin G; SARS-CoV-2; COVID-19; B-lymphocytes; immunoglobulin A immunoglobulin G
• ISSN: 0006-9248
• DOI: 10.4149/BLL_2022_039

The study was aimed at the characterization of humoral immunity in acute SARS-CoV-2 infection.
Humoral immunity plays a central role in the protection from infection due to SARS-CoV-2, causative agent of coronavirus diseases 2019 (COVID-19).
In 24 adult patients hospitalized with COVID-19, the functional subsets of circulating B-lymphocytes and SARS-CoV-2 specific IgA and IgG antibodies were analyzed using a flow cytometry and immunoassays, respectively.
Circulating plasmablasts and memory B-lymphocytes were significantly elevated and regulatory B-lymphocytes significantly decreased in the patients in comparison with 11 age- and sex-matched SARS-CoV-2 seronegative healthy adults. Next, circulating plasmablasts correlated negatively with the levels of SARS-CoV-2 specific IgG antibodies, which were detectable in 9 out of 15 tested patients. In addition, SARS-CoV-2 specific IgA antibodies were detectable in 13 of 15 tested patients and did not demonstrate correlation with any B-lymphocyte subset.
Severe course of COVID-19 is associated with significant changes of phenotypes of circulating B-lymphocytes and elevated circulating plasmablasts correlate with decreased SARS-CoV-2-specific IgG antibodies (Tab. 2, Fig. 3, Ref. 14).