Fig. 3

Expansion of plasmablasts in contrast to reduced CD4 + and CD8 + T cells in hospitalized COVID-19 patients. Human B cells were sub-grouped as follows: total B cells (CD3⁻CD19⁺), innate-like B cells (CD3CD19⁺CD21⁺CD38⁺), memory B cells (CD3CD19 + CD27⁺CD38⁻), regulatory-like cells (CD3⁻CD19⁺CD38^bright), and plasmablasts (CD3CD19 + CD27⁺CD38⁺). Data are shown as mean ± SE and scatter plots. Statistically significant differences are indicated: * p < 0.05, ** p < 0.001 and **** p < 0.0001 (Kruskal-Wallis, Dunn’s multiple comparison test)