[1] Harvard Univ, Stem Cell & Regenerat Biol, Cambridge, MA 02138 USA
[2] Massachusetts Gen Hosp, Ctr Regenerat Med, Boston, MA 02114 USA
[3] Harvard Stem Cell Inst, Cambridge, MA USA
[4] Massachusetts Gen Hosp, Ctr Canc, Ctr Transplantat Sci, Boston, MA USA