CD164 knockdown modulates CXCL12-mediated migration of CD133⁺ subsets on fibronectin. (A) Absolute percentages of CD34⁺CD38^lo/− and CD34⁺CD38⁺ cells before migration in the original CD133⁺ cell population and in the migrated fraction. The absolute percentage of each cell subset in the overall population was not significantly different before migration, irrespective of treatment (P > .05). (B) Percentage of each CD34⁺CD38^lo/− and CD34⁺CD38⁺ cell subset within the CD133⁺ population that migrated. In untreated cells (nucleofected without siRNA) or cells nucleofected with control siRNAs, 73.4% ± 0.2% and 66.8% ± 2.6%, respectively, of the total CD133⁺CD34⁺CD38^lo/− cell subset migrated to CXCL12 (Bi). This decreased to 15.2% ± 3.6% and 24.8% ± 0.1% for cells nucleofected with CD164-2 siRNAs or treated with the 103B2 mAb, respectively (P < .05 for both). In the CD34⁺CD38⁺ subset, 56.1% ± 2.7% of untreated and 52.2% ± 2.5% of cells nucleofected with control siRNA migrated to CXCL12 (Bii). This was reduced to 23.2% ± 1.7% and 31.8% ± 1.7% of cells treated with CD164-2 siRNAs or the 103B2 mAb, respectively (P < .05 for both).