Cutting Edge: Distinct B Cell Repertoires Characterize Patients with Mild and Severe COVID-19

• Published in: The Journal of immunology (1950) 2021-06, Vol.206 (12), p.2785-2790
• Main Authors: Hoehn, Kenneth B, Ramanathan, Palaniappan, Unterman, Avraham, Sumida, Tomokazu S, Asashima, Hiromitsu, Hafler, David A, Kaminski, Naftali, Dela Cruz, Charles S, Sealfon, Stuart C, Bukreyev, Alexander, Kleinstein, Steven H
• Format: Article
• Language: English
• Subjects: B-Lymphocytes - immunology; Cohort Studies; COVID-19 - immunology; Humans; SARS-CoV-2 - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.2100135

Protective immunity against COVID-19 likely depends on the production of SARS-CoV-2-specific plasma cells and memory B cells postinfection or postvaccination. Previous work has found that germinal center reactions are disrupted in severe COVID-19. This may adversely affect long-term immunity against reinfection. Consistent with an extrafollicular B cell response, patients with severe COVID-19 have elevated frequencies of clonally expanded, class-switched, unmutated plasmablasts. However, it is unclear whether B cell populations in individuals with mild COVID-19 are similarly skewed. In this study, we use single-cell RNA sequencing of B cells to show that in contrast to patients with severe COVID-19, subjects with mildly symptomatic COVID-19 have B cell repertoires enriched for clonally diverse, somatically hypermutated memory B cells ∼30 d after the onset of symptoms. This provides evidence that B cell responses are less disrupted in mild COVID-19 and result in the production of memory B cells.