CLL clonal SGs revealed by bead-immobilized anti-sIgM separation. PBMCs were incubated either with goat F(ab’)2 anti-human IgM coated beads (A) or isotype control coated beads (B). CLL SGs were identified within the CD19+ tumor population according to different SSC in the FACS Calibur. A representative case (CLL4) is shown.