BMP-6 induces cell death in human memory B cells and Ramos cells
Next, we wanted to establish whether BMP-6 also could affect the viability of normal B cells. Cell viability was determined by propidium iodide (PI) staining after culture with or without BMP-6 for 48 hours. Interestingly, BMP-6 showed a small, but reproducible mean increase of cell death from 17 to 23% (n = 5; p </= 0,003) in anti-IgM stimulated CD27+ memory B cells. Furthermore, Ramos cells showed a mean increase in cell death from 20 to 50% (n = 3, p < 0,001, figure 3) after BMP-6 treatment. In contrast, cell death of total CD19+ cells (n = 6; p </= 0,32; data not shown) or CD27-IgG- naive B cells was not significantly affected (n = 5; p </= 0,65, figure 2). 
