Epratuzumab leads to decreased surface expression of the adhesion molecules CD62L and β7 integrin on CD27negative B-cells. Comparison of the surface expression of CD62L on PBMCs from SLE patients with (grey histogram) and without (white histogram) epratuzumab incubation (a). Monocytes (CD14positive) showed a moderate but non-significant reduction of CD62L, whereas this expression was not influenced on T-cells (CD3positive) by epratuzumab. Notably, epratuzumab led to a significant reduction of the CD62L surface expression on B-cells (P <0.01). These comparative studies of CD27negative B-cells versus CD27positive B-cells demonstrated that the reduction of CD62L was confined to CD27negative B-cells (b) (P <0.01). Similarly, the surface expression of β7 integrin (c) was significantly reduced by epratuzumab on CD27negative B-cells but not on CD27positive B-cells (** P < 0.01; ns not significant, n = 9).