B cells from other LPDs display variable PC differentiation in vitro. B cells derived from the bone marrow (BM), peripheral blood (PB), or spleen of patients with various LPDs were stimulated with CD40L and F(ab′)2 anti-IgG/IgM (A) or 1 μg/mL R848 and F(ab′)2 anti-IgG/IgM (B). Each scatter plot displays the percentage of live cells expressing the stated CD marker, as determined at each time point via flow cytometry. Data from comparable intervals were grouped together. Each independent differentiation is represented by a different color. (C) The fold change in cell number at each time point was determined by manual counts for day 3 and day 6 and by flow cytometry thereafter. The cell number at each point was normalized to the number of “input” cells for that specific patient obtained at day 0.