Fig. 6. Decreased early transitional and follicular B cells in the peripheral blood of patients with severe COVID-19.

Quantitation of (A) total CD19+ B cells and (B) naïve, early transitional (T1/2), and follicular (FO) B cell subsets in the peripheral blood of patients with COVID-19 at states of convalescence (n=19), moderate disease (n=5), and severe disease (n=12) as defined by the clinical criteria listed in Table S2 as compared to healthy controls (n=4). Quantitation shown by B cell level for each individual patient with mean, standard deviation, and significance by one-way ANOVA of log % B cell value indicated (*P < 0.05, ***P < 0.001, ****P < 0.0001). Representative dot plots shown (B) with full B cell flow cytometry gating strategy outlined in Fig. S6. (C) Quantitation of naïve and FO B cell frequencies in the peripheral blood of patients with severe COVID-19 subdivided by intermediate (int, < 200 mg/L) versus high (hi, > 200 mg/L) maximum C-reactive protein (CRP) level and shown as box and whiskers plot with significance by Student’s t-test of log % B cell value indicated (*P < 0.05). (D) Association of FO B cell frequency in the peripheral blood of hospitalized COVID-19 patients (moderate and severe disease) with maximum CRP level, symptom duration at blood draw, and total length of hospital stay by linear regression with individual patients, 95% confidence bands, R² and P values shown.