[1] Univ Hosp Essen, Inst Expt Cellular Therapy, Essen, Germany
[2] Escuela Nacl Antropol & Hist, Lab Genet Mol, Mexico City, DF, Mexico
[3] Max Planck Inst Sci Human Hist, Dept Archaeogenet, Jena, Germany
[4] Univ Costa Rica, Escuela Med, San Jose, Costa Rica
[5] Royal Free Hosp, Anthony Nolan Res Inst, London, England
[6] Hosp San Juan Dios, Lab Clin, Div Banco Celulas Madre, San Jose, Costa Rica
[7] Univ Nacl Autonoma Nicaragua, Dept Ciencias Morfol, Leon, Nicaragua, Spain
[8] Anthony Nolan Res Inst, London, England
[9] UCL Canc Inst, London, England
[10] Med Coll Wisconsin, Ctr Int Blood & Marrow Transplant Res, Milwaukee, WI 53226 USA