CD38 expression increases CLL cell migration and cell spreading. (A) MEC1-GFP and MEC1-CD38H cells were added to VCAM-1-coated transwell filters in the absence or presence of 100 ng/mL CCL21 in the bottom chamber. The migration index was obtained by normalizing the values to the MEC1-GFP control cells. Data shown are the mean of 3 independent experiments ± SEM. (B) Peripheral blood mononuclear cells from 11 patients with CLL were added to VCAM-1-coated transwell filters; values represent the percentage of CD19⁺ migrated cells divided by the total number of CD19⁺ cells added to the filter. Horizontal bars indicate mean values of migrating cells for CD38^low (n = 6) and CD38^high (n = 5) CLL samples. (C) Representative images of fixed cells and quantification of the cell attachment area (μm²) of MEC1-GFP and MEC1-CD38H cells seeded on VCAM-1 (n ≥ 100 cells per population from 3 independent experiments). Scale bar, 10 μm. (D) MEC1-GFP and MEC1-CD38H cells were stained with Alexa Fluor 647–conjugated phalloidin and analyzed by flow cytometry. Values were obtained by normalizing the median fluorescent intensity to the MEC1-GFP control cells. Data shown are the mean of 5 independent experiments ± SEM. Horizontal bars indicate mean values ± SEM. *P < .05; **P < .01; *** P < .001 determined by 2-tailed Student t test. BF, bright field; IRM, interference reflection microscopy.