Differentiation of peripheral blood B cells into polyclonal plasmablastic cells.

(A) Percentages of CD20⁻/CD38⁺⁺ cells were evaluated on purified PB B cells, on unseparated cells obtained after the 2-step culture, and on sorted cells. Viable cells were gated by size and granulometry. (B) Giemsa staining of sorted CD20⁻/CD38⁺⁺ cells showing their plasma cell morphology and a mitosis figure (arrow). Original magnification, × 1000. (C) Unseparated cells were stained with anti-κ (brown) and anti-λ (red) light chain. Original magnification, × 400. (D) Percentages of CD20⁻/CD38⁺⁺ cells in the S-phase were determined using PI staining. They ranged from 24% to 36% in 5 separate experiments.