[1] Childrens Hosp Boston, Div Hematol Oncol, Boston, MA USA
[2] Univ Cincinnati, Dept Pathol & Lab Med, Cincinnati, OH USA
[3] Univ London Imperial Coll Sci Technol & Med, Div Cell & Mol Biol, London, England
[4] Massachusetts Gen Hosp, Ctr Regenerat Med, Boston, MA 02114 USA
[5] Harvard Univ, Sch Med, Childrens Hosp Boston, Boston, MA USA
[6] Harvard Stem Cell Inst, Boston, MA USA