[1] Seoul Natl Univ, Dept Internal Med, Bundang Hosp, Seongnam, South Korea
[2] Catholic Univ Korea, Seoul St Marys Hosp, Catholic Blood & Marrow Transplantat Ctr, Leukemia Res Inst,Dept Hematol,Coll Med, Seoul, South Korea
[3] S Eugenio Hosp, Haematol Unit, Rome, Italy
[4] Imperial Coll London, Ctr Haematol, London, England
[5] Univ Birmingham, Med Sch, Sheffield, S Yorkshire, England
[6] Mem Sloan Kettering Canc Ctr, Myeloproliferat Neoplasms Program, Leukemia Serv, 1275 York Ave, New York, NY 10021 USA