Dynamics of CXCR4 expression in CLL. CXCR4 expression was determined in SGs 1 to 4 and in the whole population using the FACS CANTO II. (A) CXCR4 expression on the CLL CD19⁺ cells from SG1-4. (B) expression of IgM (upper histogram) or CXCR4 (lower histogram) on CD19⁺/CD5⁺ cells from case CLL2 at different time points (0, 0.5, 8, or 72 hours) in the whole population following culture in vitro. (C) Expression of CXCR4 on the CD19⁺/CD5⁺ CLL cells at early time points (0, 0.5, 2, 4, or 8 hours) following culture in vitro. Lines indicate individual cases. I.C., isotype control at time point 0.