Surface expression of CD44, β7-integrin, and CD62L on CD19+ B cells was preferentially reduced by milatuzumab on CD27- naïve B cells. (A) Surface expression of CD44 after incubation of peripheral blood mononuclear cells for 90 minutes at 37°C in 5% CO2 with or without milatuzumab (n = 7) or IgG1/IVIG (n = 7). Milatuzumab led to a significant reduction of the expression of CD44 on CD19+ B cells, especially on CD27- naïve B cells (Wilcoxon test). (B) Expression of β7-integrin was significantly reduced (Wilcoxon test) on CD19+ B cells, mainly confined to CD27- naïve B cells after milatuzumab incubation (n = 8), but not influenced by IgG1/IVIG (n = 7). (C) Milatuzumab (n = 9) significantly reduced the expression of CD62L (Wilcoxon test) on CD19+ B cells, especially on CD27- naïve B cells, whereas IgG1/IVIG (n = 8) did not modify this expression. The expression of the surface molecules CD44, β7-integrin, and CD62L on CD27+ memory B cells was not influenced by milatuzumab. *P ≤ 0.05; **P ≤ 0.01. IVIG, intravenous immunoglobulin; ns, not significant.