Enhanced migration of CD27negative B-cells from SLE patients towards CXCL12 after epratuzumab incubation. To assess the migration towards CXCL12, CXCL13 and CXCR3 ligands of PBMCs from eight SLE patients, we performed transwell migration assays after epratuzumab incubation (10 μg/mL for 90 minutes). The migration of different cell types towards CXCL12 was analyzed by flow cytometry [(T-cells, CD3positive), (monocytes, CD14positive), (total B-cells CD19positive); CD27negative B-cells CD27positve B-cells] and epratuzumab incubation lead to a significantly enhanced migration of B-cells (a) (*P < 0.05). No effect of epratuzumab was observed on T-cells and on monocytes. Migration of all cell types, including B-cells, towards CXCL13 and CXCR3 ligands was unaffected by epratuzumab. (b) Studies of CD27negative and CD27positive B-cells from SLE patients revealed that the increased migration toward CXCL12 was primarily restricted to CD27negative B-cells (** P < 0.01).