Effect of the CM of bone marrow plasma cells on (A) HUVEC proliferation, (B) HUVEC chemotaxis, and (C) human monocyte chemotaxis. In (A), low-density cultures of HUVEC (2.5 × 103 cells per well) were exposed on days 0, 2, and 4 with complete medium (positive control), starvation medium (negative control), and negative control medium supplemented 1:1 (vol/vol) with plasma cell CM. HUVEC were counted on day 6. Each dot represents the mean of four determinations for each CM or control. In (B), Kaposi cell CM (positive control), DMEM.1% BSA (negative control), and plasma cell CM were added to the lower compartment, and 1.2 × 105 HUVEC were placed in the upper compartment. Cells that migrated to the lower surface of a gelatin-coated filter separating the compartments were counted after 6 hours. Each dot is the mean of three determinations for each CM or control. In (C), a formylpeptide solution (positive control), RPMI-1640.1% BSA (negative control), and plasma cell CM were added to the lower compartment, and 2 × 105human monocytes were placed in the upper compartment. Cells that migrated to the lower surface of a polycarbonate filter were counted after 2 hours. Each dot is the mean of six determinations for each CM or control. In all assays, reproducibility was ≤±10% of the mean value of each CM. For all assays, the cutoff corresponds to the mean plus 3 SD of the negative control medium. The number of CM tested for each group of patients is given in brackets. The mean ± 1 SD is given for each group.
